JP7228957B2 - Optical film with adhesive layer, in-cell type liquid crystal panel and liquid crystal display device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an optical film with an adhesive layer, an in-cell liquid crystal panel, and a liquid crystal display device.

Optical films such as polarizing plates and retardation films, which are components of liquid crystal display devices, are usually bonded to liquid crystal panel components such as liquid crystal cells via adhesives. In a typical embodiment, the optical film is handled in the form of a pressure-sensitive adhesive layer-attached optical film having a pressure-sensitive adhesive layer on at least one surface thereof in the manufacturing process of a liquid crystal display device. With such an optical film with an adhesive layer, a liquid crystal panel can be constructed simply by removing the release liner that protects the adhesive layer and attaching the exposed adhesive surface to an adherend. It is advantageous in terms of sex. On the other hand, static electricity is generated when the release liner is removed as described above. Such static electricity affects the alignment of the liquid crystal in the liquid crystal cell, and causes, for example, display unevenness of the liquid crystal (hereinafter also referred to as "static unevenness"). Therefore, measures such as providing an antistatic layer in an optical film having a pressure-sensitive adhesive layer or including a conductive agent in the pressure-sensitive adhesive layer have been taken.

As for the countermeasure against static electricity as described above, the method of simply increasing the conductivity cannot be adopted depending on the device configuration. For example, an improvement in conductivity may adversely affect the touch sensor sensitivity in a touch panel-equipped liquid crystal display device that has already been put into practical use. The capacitive method used in touch panel LCD devices is an input device that detects and drives changes in capacitance caused by finger contact with the touch panel. However, if the electric field is disturbed due to the presence of the antistatic layer, the sensitivity of the touch panel is lowered. Against this background, the touch panel mounted type is designed to have conductivity that can achieve both prevention of static electricity unevenness and touch sensor sensitivity. Patent document 1 is mentioned as a prior art document which discloses this kind of prior art. Specifically, Patent Document 1 relates to a so-called in-cell liquid crystal panel in which electrodes related to a touch sensor are arranged inside a liquid crystal cell (that is, inside transparent substrates sandwiching a liquid crystal layer). Patent Document 2 discloses an optical film with a pressure-sensitive adhesive layer, in which an anchor layer containing a conductive polymer is arranged between the optical film and the pressure-sensitive adhesive layer.

WO2017/057097 JP 2015-87539 A

For example, in the touch panel type liquid crystal display device as described above, there is a demand to improve the conductivity of the liquid crystal panel and prevent the occurrence of electrostatic unevenness to a high degree while maintaining good touch sensor sensitivity. In particular, in the in-cell type liquid crystal panel, unlike the on-cell type, a conductive layer such as an ITO layer is not provided on the surface of the panel. A configuration in which an antistatic anchor layer is provided between layers to increase the conductivity of the entire panel is preferable (Patent Document 1). In such a configuration, if the amount of the conductive agent (typically an ionic compound) in the adhesive layer is increased, further improvement in conductivity can be expected while maintaining good touch sensor sensitivity. However, it has been found that increasing the amount of the ionic compound in the pressure-sensitive adhesive layer reduces the adhesion (that is, anchoring property) between the antistatic anchor layer and the pressure-sensitive adhesive layer.

The present invention relates to improvements in an optical film with a pressure-sensitive adhesive layer created in view of the above circumstances, and an optical film with a pressure-sensitive adhesive layer that has good conductivity and excellent anchoring properties of the pressure-sensitive adhesive layer. intended to provide Another object of the present invention is to provide an in-cell type liquid crystal panel and a liquid crystal display device which have good touch sensor sensitivity and improved antistatic property by including the optical film with an adhesive layer. It is to be.

According to the present specification, an optical film with a pressure-sensitive adhesive layer comprising an optical film, an antistatic layer provided on at least one surface of the optical film, and a pressure-sensitive adhesive layer disposed on the antistatic layer provided. In this pressure-sensitive adhesive layer-attached optical film, the pressure-sensitive adhesive layer contains polymer A as a base polymer and an ionic compound. Also, the content of the ionic compound in the adhesive layer is 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer. Meanwhile, the antistatic layer includes a conductive polymer and a polymer B. The polymer A has a functional group a, and the polymer B has a functional group b that interacts with the functional group a. The polymer B contains 10 mol % or less of polyether units in its molecule.

According to the above configuration, since the antistatic layer contains a conductive polymer and the adhesive layer contains an ionic compound, the conductivity of the laminated film is increased by the two layers of the antistatic layer and the adhesive layer, and good conductivity is obtained. is obtained. For example, when the optical film with a pressure-sensitive adhesive layer is used for a liquid crystal panel, the occurrence of static electricity unevenness is highly prevented. In addition, the conductivity of this laminated film can be adjusted by adjusting the composition of the two layers, the antistatic layer and the adhesive layer. Good touch sensor sensitivity can be maintained while preventing the occurrence of Furthermore, since the polymer A in the adhesive layer and the polymer B in the antistatic layer have interacting functional groups a and b, respectively, the antistatic layer and the adhesive layer are easily adhered. Here, the interaction between two functional groups refers to the action of different molecules bonding or attracting each other, such as covalent bond, dipole-dipole interaction, hydrogen bond, van der Waals force, and the like.

In addition, in the above configuration, the pressure-sensitive adhesive layer contains 5 to 20 parts by weight of an ionic compound with respect to 100 parts by weight of the base polymer from the viewpoint of improving conductivity, but this may cause a decrease in anchoring properties. . Specifically, as a result of analysis and examination by TOF-SIMS (time-of-flight secondary ion mass spectrometry) on the cross section of the laminate of the optical film with the pressure-sensitive adhesive layer, the present inventors found that the antistatic layer contained When the polymer B has a predetermined amount or more of polyether units in addition to the functional group b, the ionic compound contained in the pressure-sensitive adhesive layer is attracted to the antistatic layer and migrates to the interface with the antistatic layer. , and obtained the knowledge that this phenomenon correlates with the decrease in anchoring ability. Therefore, in the above configuration, the polymer B contained in the antistatic layer has a polyether unit content of not more than a predetermined amount. This can prevent the migration of the ionic compound to the antistatic layer side due to the polyether unit of the polymer B, and suppress the deterioration of the anchoring property. This reduction in anchoring ability can be suppressed without reducing the amount of the ionic compound in the pressure-sensitive adhesive layer, so it is compatible with the improvement in conductivity.
In short, according to the above configuration, an optical film with a pressure-sensitive adhesive layer having good conductivity and excellent anchoring properties of the pressure-sensitive adhesive layer is realized. When the optical film with a pressure-sensitive adhesive layer having this structure is used for, for example, a liquid crystal panel, it is possible to improve the antistatic property. Moreover, when applied to a touch sensor mounted type, good touch sensor sensitivity can be exhibited. Furthermore, the excellent anchoring property of the pressure-sensitive adhesive layer brings about improvements in processability and reworkability when manufacturing an optical structure (for example, a liquid crystal panel, and eventually a liquid crystal display device) to which the optical film with the pressure-sensitive adhesive layer is applied. This also leads to the fact that the structure to which the pressure-sensitive adhesive layer-attached optical film is adhered has excellent durability.

In a preferred embodiment of the technology disclosed herein (including optical films with pressure-sensitive adhesive layers, liquid crystal panels, liquid crystal panels with touch sensors, in-cell liquid crystal panels, and liquid crystal display devices; the same shall apply hereinafter), the functional group a and one of the functional groups b is at least one selected from the group consisting of a carboxy group, an acid anhydride group, a hydroxyl group and a thiol group, and the other is selected from the group consisting of an oxazoline group and an isocyanate group. At least one. From the above functional group species, one functional group species is selected, and the other functional group species is selected so that the functional group a and the functional group b interact with each other. Based on the interaction of the functional groups, excellent anchoring properties are likely to be obtained.

In a preferred embodiment of the technology disclosed herein, both the antistatic layer and the pressure-sensitive adhesive layer have surface resistance values within the range of 1×10 ⁸ to 1×10 ¹⁰ Ω/□. By setting the surface resistance value of the antistatic layer and the pressure-sensitive adhesive layer to 1×10 ¹⁰ Ω/□ or less, the occurrence of static electricity unevenness can be highly prevented in, for example, liquid crystal panel applications due to their conductivity. Further, by setting the surface resistance value of each layer to 1×10 ⁸ Ω/□ or more, for example, in a touch sensor-equipped liquid crystal panel, good touch sensor sensitivity is preferably ensured.

In one preferred aspect of the technology disclosed herein, said ionic compound is selected from alkali metal salts and organic cation-anion salts. Among others, the ionic compound is more preferably an ionic liquid (eg, organic cation-anion salt) having a melting point of 40° C. or less. By using the ionic compound of the above kind, the deterioration of the anchoring property of the pressure-sensitive adhesive layer can be preferably suppressed while the conductivity of the pressure-sensitive adhesive layer is obtained.

In a preferred aspect of the technology disclosed here, the conductive polymer is a thiophene-based polymer. By using a thiophene-based polymer as the conductive polymer, the antistatic layer can preferably obtain conductivity suitable for use in liquid crystal panels (for example, touch panel-mounted liquid crystal panels).

In a preferred embodiment of the technology disclosed here, the polymer A is an acrylic polymer. By using an acrylic polymer as the base polymer of the pressure-sensitive adhesive layer, the optical film arranged on the back surface can be adhered and fixed to an adherend such as a liquid crystal cell.

In a preferred embodiment of the technology disclosed here, the polymer B is an oxazoline group-containing polymer. By using an oxazoline group-containing polymer as the polymer B contained in the antistatic layer, the adhesion with the adhesive layer is preferably improved, and the effect of making the polyether unit in the polymer B 10 mol% or less is preferable. demonstrated.

Further, according to this specification, there is provided an in-cell liquid crystal panel comprising a liquid crystal cell and any one of the pressure-sensitive adhesive layer-attached optical films disclosed herein. In this liquid crystal panel, the liquid crystal cell includes: a liquid crystal layer containing liquid crystal molecules; a touch sensing electrode portion disposed between the first transparent substrate and the second transparent substrate; In addition, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached optical film is attached to the surface of the first transparent substrate. In the in-cell type, which does not have a conductive layer on the panel surface, it is essential to improve conductivity by means of an optical film with a pressure-sensitive adhesive layer. By using the optical film with a pressure-sensitive adhesive layer disclosed herein in an in-cell type liquid crystal panel, it is possible to obtain antistatic property due to its high conductivity while maintaining good touch sensor sensitivity.
In this specification, the "touch sensing electrode portion" is a concept including at least one (preferably both) of the detection electrode and the drive electrode involved in touch sensing, and the detection electrode and the drive electrode are integrally formed. It also includes integrated electrodes.

Further, according to this specification, there is provided a liquid crystal display device comprising any one of the in-cell liquid crystal panels disclosed herein. The in-cell type liquid crystal panel is highly suppressed in occurrence of static electricity unevenness and has good touch sensor sensitivity. Furthermore, since the adhesive layer has excellent anchoring properties, it is also excellent in workability and durability. Therefore, by using the in-cell type liquid crystal panel disclosed herein, a high-quality liquid crystal display device that is less likely to cause defects can be provided.

1 is a schematic cross-sectional view showing an optical film with a pressure-sensitive adhesive layer according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing a semi-in-cell liquid crystal panel according to one embodiment; FIG. 1 is a schematic cross-sectional view showing an on-cell liquid crystal panel according to one embodiment; FIG. FIG. 4 is a graph schematically showing TOF-SIMS analysis results for a configuration using polymer B with polyether units exceeding 10 mol %. FIG. 4 is a graph schematically showing TOF-SIMS analysis results for a structure using a polymer B having a polyether unit content of 10 mol % or less.

Preferred embodiments of the present invention are described below. Matters other than the matters specifically mentioned in the present specification, which are necessary for the implementation of the present invention, are based on the teaching of the implementation of the invention described in the present specification and the common general knowledge at the time of filing. can be understood by those skilled in the art. The present invention can be implemented based on the contents disclosed in this specification and common general technical knowledge in the field.
In the drawings below, members and portions having the same function are denoted by the same reference numerals, and redundant description may be omitted or simplified. Moreover, the embodiments described in the drawings are schematics for the purpose of clearly explaining the present invention and are not intended to accurately represent the size or scale of the products and parts actually provided.

<Configuration>
FIG. 1 schematically shows a structural example of the pressure-sensitive adhesive layer-attached optical film disclosed herein. This adhesive layer-attached optical film 10 has an optical film 11, an antistatic layer 13, and an adhesive layer 12 in this order. Specifically, the antistatic layer 13 is provided on one surface (first surface) 11A of the optical film 11, and one surface of the antistatic layer 13 (the surface opposite to the optical film 11 side) An adhesive layer 12 is arranged thereon. Moreover, the optical film 10 with an adhesive layer may have a surface treatment layer 14 on the other surface (also referred to as the second surface or back surface) 11B of the optical film 11 . The optical film 10 with a pressure-sensitive adhesive layer is used by attaching the pressure-sensitive adhesive surface 12A of the pressure-sensitive adhesive layer 12 to the surface of an adherend (object to be protected, for example, an optical component such as a transparent substrate on the viewing side of a liquid crystal cell). In the optical film 10 with a pressure-sensitive adhesive layer before use (that is, before sticking to an adherend), the pressure-sensitive adhesive surface (sticking surface to the adherend) 12A of the pressure-sensitive adhesive layer 12 is the release surface at least on the pressure-sensitive adhesive layer 12 side. It may be in the form of being protected by a release liner (not shown). A surface protective film (not shown) may be provided on the back surface of the optical film 10 with an adhesive layer (the outer surface of the surface treatment layer 14, or the back surface of the optical film 11 when the surface treatment layer 14 is not provided). can.

<Optical film>
The optical film disclosed herein includes a polarizing film (also referred to as a polarizing plate), a retardation film (also referred to as a retardation plate, including a wavelength plate), which is used as an optical member in an image display device such as a liquid crystal display device. It may be called an optical compensation film, brightness enhancement film, light diffusion film, reflection film, anti-transmission film, or the like. An optical film according to a preferred embodiment is a polarizing film and a retardation film. One of these can constitute an optical film alone, and two or more of them can be combined (typically laminated) to be used as an optical film. Such an optical film may be, for example, a laminate of a polarizing layer made of a polarizing film and another optical layer such as a retardation layer film. A polarizing film will be described below as a preferred example of the optical film, but the technology disclosed herein is not intended to be limited to this.

A polarizing film used as a preferred example of the optical film disclosed herein usually comprises a polarizer and a transparent protective film disposed on at least one surface (preferably both surfaces) of the polarizer. . The polarizer is not particularly limited, and for example, a hydrophilic polymer film that is uniaxially stretched after being adsorbed with a dichroic substance such as iodine or a dichroic dye is used. Hydrophilic polymer films include polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene/vinyl acetate copolymer films. As a polarizer, a polyene-based oriented film such as dehydrated PVA or dehydrochlorinated polyvinyl chloride can be used. Among them, a polarizer composed of a PVA-based film and a dichroic substance such as iodine is preferable.

The thickness of the polarizer is not particularly limited and is generally about 80 μm or less. In addition, from the viewpoint of thinning, a thin polarizer having a thickness of about 10 μm or less (preferably about 1 to 7 μm) can be used. A thin polarizer has little unevenness in thickness and is excellent in visibility, and is also excellent in durability because it has little dimensional change. Using a thin polarizer also leads to thinning of the polarizing film.

As a material constituting the transparent protective film, for example, a thermoplastic resin which is excellent in transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, etc. is preferably used. Specific examples of such thermoplastic resins include cellulose resins such as triacetyl cellulose (TAC), polyester resins, polyethersulfone resins, polysulfone resins, polycarbonate resins, polyamide resins, polyimide resins, polyolefin resins, (meth)acrylic resins, Examples include resins, cycloolefin resins (typically norbornene resins), polyarylate resins, polystyrene resins, PVA resins, and mixtures of two or more of these. In a preferred embodiment, a transparent protective film made of a thermoplastic resin such as TAC is placed on one side of the polarizer, and a cycloolefin resin (typically norbornene resin) or ( A configuration in which a transparent protective film made of meth)acrylic resin is arranged may be employed. In another preferred embodiment, a transparent protective film made of a thermoplastic resin such as TAC is disposed on one surface of the polarizer, and a transparent protective film made of (meth)acrylic, urethane, or the like is disposed on the other surface of the polarizer. Thermosetting resins such as acrylic urethane, epoxy, and silicone or ultraviolet curable resins can be used. These transparent protective films can be laminated on the polarizer via a PVA-based adhesive or the like. The transparent protective film may contain one or more of any suitable additives depending on the purpose.

The adhesive used for bonding the polarizer and the transparent protective film is not particularly limited as long as it is optically transparent, and various forms such as water-based, solvent-based, hot-melt, radical-curing, and cationic-curing types are used. be able to. Among them, a water-based adhesive or a radical curing adhesive is preferable.

Moreover, a surface treatment layer may be provided on the back surface of the optical film (that is, the surface opposite to the side on which the antistatic layer is provided). The surface treatment layer can be provided on the above transparent protective film used for the optical film, or can be provided on the optical film separately from the transparent protective film.

A suitable example of the surface treatment layer is a hard coat layer. As a material for forming the hard coat layer, for example, a thermoplastic resin, or a material that is cured by heat or radiation can be used. Materials used include radiation-curable resins such as thermosetting resins, ultraviolet-curable resins, and electron-beam-curable resins. Among them, an ultraviolet curable resin is preferable. Ultraviolet curable resins are excellent in workability because they can efficiently form a cured resin layer by curing treatment using ultraviolet irradiation. As the curable resin, one or more of polyester-based, acrylic-based, urethane-based, amide-based, silicone-based, epoxy-based, and melamine-based resins can be used. It can be in the form of containing. Radiation-curable resins (typically UV-curable resins) are particularly preferred because they do not require heat (which can cause substrate damage) and are excellent in processing speed.

Other examples of the surface treatment layer include an antiglare treatment layer and an antireflection layer for the purpose of improving visibility. An antiglare treatment layer or an antireflection layer may be provided on the hard coat layer. The constituent material of the antiglare treatment layer is not particularly limited, and for example, a radiation-curable resin, a thermosetting resin, a thermoplastic resin, or the like can be used. Titanium oxide, zirconium oxide, silicon oxide, magnesium fluoride, etc. may be used as the antireflection layer. The antireflection layer may have a multi-layer structure consisting of multiple layers. Other examples of surface treatment layers include anti-sticking layers.

When the technology disclosed herein is carried out in a manner including a surface-treated layer, the surface-treated layer may contain an antistatic agent to impart electrical conductivity. As the antistatic agent, a conductive agent described later can be used without particular limitation.

The thickness of the optical film disclosed herein (the total thickness thereof when composed of a plurality of layers) is not particularly limited, and is, for example, about 1 μm or more, usually about 10 μm or more, and about 20 μm. The above is appropriate. For example, when a transparent protective film is provided, the thickness of the optical film is preferably about 30 μm or more, more preferably about 50 μm or more, and even more preferably about 70 μm or more from the viewpoint of protection. The upper limit of the optical film is not particularly limited, and is, for example, about 1 mm or less, usually about 500 μm or less, and about 300 μm or less is suitable. From the viewpoint of optical properties and thickness reduction, the thickness is preferably about 150 μm or less, more preferably about 120 μm or less, and even more preferably about 100 μm or less.

<Adhesive layer>
The pressure-sensitive adhesive constituting the pressure-sensitive adhesive layer disclosed herein is not particularly limited as long as the polymer A as the base polymer constituting the pressure-sensitive adhesive layer has a functional group a. It may be a pressure-sensitive adhesive layer containing one or more selected from various pressure-sensitive adhesives such as silicone-based, vinyl alkyl ether-based, vinylpyrrolidone-based, acrylamide-based, and cellulose-based adhesives. Therefore, the polymer A as the base polymer constituting the pressure-sensitive adhesive layer includes acrylic polymers, rubber polymers, urethane polymers, silicone polymers, vinyl alkyl ether polymers, vinylpyrrolidone polymers, acrylamide polymers, and cellulose polymers. etc. Among them, acrylic pressure-sensitive adhesives are preferable from the viewpoints of transparency, appropriate wettability, adhesive properties such as cohesiveness and adhesiveness, weather resistance, heat resistance, and the like. Hereinafter, the technology disclosed herein will be described in more detail, taking as a main example a configuration in which the pressure-sensitive adhesive layer is an acrylic pressure-sensitive adhesive layer, but the intention is to limit the pressure-sensitive adhesive layer to that made of an acrylic pressure-sensitive adhesive. isn't it.

(Acrylic adhesive)
The acrylic pressure-sensitive adhesive employed in a preferred embodiment is a pressure-sensitive adhesive having an acrylic polymer as a base polymer (the main component among the polymer components contained in the pressure-sensitive adhesive, i.e., a component contained in an amount of more than 50% by weight). Say. The term "acrylic polymer" refers to a monomer having at least one (meth)acryloyl group in one molecule (hereinafter sometimes referred to as "acrylic monomer") as the main constituent monomer component (monomer , that is, a component that accounts for 50% by weight or more of the total amount of monomers constituting the acrylic polymer). The above-mentioned "(meth)acryloyl group" is meant to comprehensively refer to acryloyl groups and methacryloyl groups. Similarly, "(meth)acrylate" is meant to collectively refer to acrylates and methacrylates.

(acrylic polymer)
The acrylic polymer, which is the base polymer of the acrylic pressure-sensitive adhesive, is typically a polymer containing alkyl (meth)acrylate as a main constituent monomer component. As the alkyl (meth)acrylate, for example, a compound represented by the following formula (1) can be preferably used.
_CH2 =C( ^R1 ) ^COOR2 (1)
Here, R ¹ in the above formula (1) is a hydrogen atom or a methyl group. R ² is an alkyl group having 1 to 20 carbon atoms (meaning that it includes a chain alkyl group and an alicyclic alkyl group). Since it is easy to obtain a pressure-sensitive adhesive with excellent adhesive properties, R ² is a chain alkyl having 1 to 18 carbon atoms (hereinafter, such a carbon atom number range may be referred to as C _1-18 .) Alkyl (meth)acrylates which are groups (meaning including linear alkyl groups and branched alkyl groups) are preferred, and alkyl (meth)acrylates having a C _1-14 chain alkyl group are more preferred. Specific examples of the C _1-14 chain alkyl group include methyl group, ethyl group, propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group, t-butyl group, n-pentyl group, isoamyl group, neopentyl group, n-hexyl group, n-heptyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, n-nonyl group, isononyl group, n-decyl group, isodecyl group, n-undecyl group, n-dodecyl group, n-tridecyl group, n-tetradecyl group and the like. Alicyclic alkyl groups that can be selected as R ² include a cyclohexyl group, an isobornyl group, and the like.

In a preferred embodiment, about 50% by weight or more, more preferably about 60% by weight or more, for example about 70% by weight or more, of the total amount of monomers used for synthesizing the acrylic polymer (hereinafter also referred to as "all raw material monomers"). is a chain alkyl (meth)acrylate in which R ² in the above formula (1) is C _1-18 (more preferably C _1-14 , still more preferably C _4-10 chain (meth)alkyl acrylate, such as n one or both of butyl acrylate (BA) and 2-ethylhexyl acrylate (2EHA)). An acrylic polymer obtained from such a monomer composition is preferred because it facilitates the formation of a pressure-sensitive adhesive exhibiting adhesive properties suitable for the applications disclosed herein. The proportion of C _1-18 (for example, C _1-14 , typically preferably C _4-10 ) chain alkyl (meth)acrylate in the total amount of the above monomers is determined by introduction of functional group a, phase difference adjustment, From the viewpoint of refractive index adjustment, it is suitable to be approximately 95% by weight or less, preferably approximately 90% by weight or less, more preferably 85% by weight or less (for example, 80% by weight or less).

From the viewpoints of adhesive properties, durability, adjustment of retardation, adjustment of refractive index, etc., it is preferable to use (meth)acrylate having an aromatic ring structure as a monomer used for synthesizing the acrylic polymer. Examples of aromatic ring structures of (meth)acrylates having an aromatic ring structure include benzene ring, naphthalene ring, thiophene ring, pyridine ring, pyrrole ring, and furan ring. Among them, (meth)acrylates having a benzene ring or a naphthalene ring are preferred. As the (meth)acrylate having an aromatic ring structure, various aryl(meth)acrylates, arylalkyl(meth)acrylates, aryloxyalkyl(meth)acrylates, and the like can be used.

Specific examples of (meth)acrylates having an aromatic ring structure include phenyl (meth)acrylate, o-phenylphenol (meth)acrylate, phenoxy (meth)acrylate, phenoxyethyl (meth)acrylate, and phenoxypropyl (meth)acrylate. Acrylate, benzyl (meth)acrylate, phenoxyethylene glycol (meth)acrylate, phenoxydiethylene glycol (meth)acrylate, ethylene oxide-modified nonylphenol (meth)acrylate, ethylene oxide-modified cresol (meth)acrylate, phenol ethylene oxide-modified (meth)acrylate, Phenoxy-2-hydroxypropyl (meth)acrylate, methoxybenzyl (meth)acrylate, chlorobenzyl (meth)acrylate, cresyl (meth)acrylate, polystyryl (meth)acrylate, hydroxyethylated β-naphthol acrylate, 2-naphthoxyethyl (meth)acrylate ) acrylate, 2-(4-methoxy-1-naphthoxy)ethyl (meth)acrylate, thiophenyl (meth)acrylate, pyridyl (meth)acrylate, pyrrolyl (meth)acrylate, polystyryl (meth)acrylate and the like. Those having a biphenyl ring such as biphenyl (meth)acrylate can also be used. These can be used individually by 1 type or in combination of 2 or more types. Among them, phenoxyethyl (meth)acrylate and benzyl (meth)acrylate are more preferable.

When using a (meth)acrylate having an aromatic ring structure, its content is appropriately set based on adhesive properties, optical properties, and the like. The (meth)acrylate having an aromatic ring structure is suitably about 5% by weight or more of the total amount of monomers used in the synthesis of the acrylic polymer, and the effect of the (meth)acrylate having an aromatic ring structure ( From the viewpoint of improving durability, improving liquid crystal display unevenness, etc.), the content is preferably about 10% by weight or more, more preferably about 15% by weight or more (for example, about 20% by weight or more). The upper limit of the amount of (meth)acrylate having an aromatic ring structure is appropriately about 30% by weight or less. Preferably less than about 25% by weight (eg less than 22% by weight).

The functional group a of the base polymer, polymer A (typically an acrylic polymer), is typically introduced into the polymer A molecule by copolymerizing a monomer having the functional group a. The above functional group a interacts with a functional group b contained in the antistatic layer, which will be described later, to enhance the adhesion between the antistatic layer and the pressure-sensitive adhesive layer. In addition, it can become a cross-linking point in the pressure-sensitive adhesive layer and improve the cohesive strength and heat resistance of the pressure-sensitive adhesive. It is also possible to adjust the glass transition temperature (Tg) of the polymer A and adjust the adhesive property by using an appropriate amount of the functional group a-containing monomer. The form of introduction of the functional group a is not limited to the copolymerization of the monomer containing the functional group a. It can also be introduced by adding

The functional group a is not particularly limited as long as it interacts with the functional group b. Functional group a can be selected from, for example, one of the group consisting of a carboxy group, an acid anhydride group, a hydroxyl group and a thiol group, or the group consisting of an oxazoline group and an isocyanate group. As the functional group a, one type may be employed alone, or two or more types may be used. Among them, the functional group a is preferably at least one functional group selected from the group consisting of a carboxy group, an acid anhydride group, a hydroxyl group and a thiol group. Preferable examples of functional group a-containing monomers to be copolymerized in polymer A (typically acrylic polymer) are carboxy group-containing monomers, acid anhydride group-containing monomers, and hydroxyl group-containing monomers. A thiol group can be introduced by adding a compound containing a thiol group to polymer A at an appropriate timing after polymerization of polymer A using an appropriate chemical reaction.

Carboxy group-containing monomers include ethylenically unsaturated monocarboxylic acids such as acrylic acid (AA), methacrylic acid (MAA), carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate; itaconic acid, maleic acid, fumaric acid , crotonic acid, isocrotonic acid, and ethylenically unsaturated dicarboxylic acids such as citraconic acid;
Acid anhydride group-containing monomers include acid anhydrides such as maleic anhydride, itaconic anhydride, and the ethylenically unsaturated dicarboxylic acids described above.
Hydroxyl group-containing monomers include 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate. , 2-hydroxyhexyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate, (4 - hydroxyalkyl (meth)acrylates such as hydroxymethylcyclohexyl)methyl (meth)acrylate; alkylene glycol (meth)acrylates such as polyethylene glycol mono(meth)acrylate and polypropylene glycol mono(meth)acrylate; vinyl alcohol, unsaturated alcohols such as allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, diethylene glycol monovinyl ether;
These functional group-containing monomers may be used singly or in combination of two or more.

Functional group-containing monomers other than those described above may be copolymerized with the acrylic polymer in the technique disclosed herein. Such a monomer can be used, for example, for the purpose of adjusting the Tg of the acrylic polymer, adjusting the adhesion performance, and the like. For example, monomers capable of improving the cohesive strength and heat resistance of the adhesive include sulfonic acid group-containing monomers, phosphoric acid group-containing monomers, cyano group-containing monomers, and the like. In addition, as a monomer that introduces a functional group that can be a cross-linking base point into the acrylic polymer or that can contribute to the improvement of adhesion to an adherend such as glass, an amide group-containing monomer, an amino group-containing monomer, and an imide group-containing monomer can be used. , epoxy group-containing monomers, nitrogen atom-containing ring-containing monomers, keto group-containing monomers, isocyanate group-containing monomers, alkoxysilyl group-containing monomers, and the like. Among them, amide group-containing monomers, amino group-containing monomers, and monomers having a nitrogen atom-containing ring, as exemplified below, are preferably used.

Amido group-containing monomers: for example, (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N-butyl(meth)acrylamide, N-methylol(meth)acrylamide, N-methylolpropane(meth)acrylamide, N- methoxymethyl(meth)acrylamide, N-butoxymethyl(meth)acrylamide;
Amino group-containing monomers: for example aminoethyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, t-butylaminoethyl (meth)acrylate.
Monomers having a nitrogen atom-containing ring: such as N-vinyl-2-pyrrolidone, N-methylvinylpyrrolidone, N-vinylpyridine, N-vinylpiperidone, N-vinylpyrimidine, N-vinylpiperazine, N-vinylpyrazine, N-vinyl pyrrole, N-vinylimidazole, N-vinyloxazole, N-vinylmorpholine, N-vinylcaprolactam, N-(meth)acryloylmorpholine, N-(meth)acryloylpyrrolidone;

The content of the functional group-containing monomer is not particularly limited, and is usually about 40% by weight or less, and about 30% by weight of the total amount of monomers used to synthesize the base polymer (typically acrylic polymer). The following is suitable, and from the viewpoint of adhesion properties, etc., it is preferably about 20% by weight or less, more preferably about 15% by weight or less, and still more preferably 10% by weight or less (for example, 5% by weight or less). The lower limit of the content of the functional group-containing monomer in the total amount of monomers used to synthesize the base polymer is usually about 0.001% by weight or more, and about 0.01% by weight or more is suitable. From the viewpoint of preferably exerting the effect of monomer copolymerization, the amount is preferably about 0.1% by weight or more, more preferably about 0.5% by weight or more, and even more preferably about 1% by weight or more.

In addition, the content of the functional group a-containing monomer is not particularly limited, and from the viewpoint of adhesive properties, etc., it should be about 20% by weight or less of the total amount of monomers used to synthesize the base polymer (typically acrylic polymer). preferably about 15% by weight or less, more preferably about 10% by weight or less (for example, about 5% by weight or less). The lower limit of the content of the functional group a-containing monomer in the total amount of monomers used for the synthesis of the base polymer is usually about 0.001% by weight or more, and about 0.01% by weight or more is suitable. From the viewpoint of preferably exhibiting the anchoring property improvement effect based on a, the content is preferably about 0.1% by weight or more, more preferably about 0.5% by weight or more, and even more preferably about 1% by weight or more.

In a preferred embodiment, at least one (preferably both) of a carboxy group-containing monomer and a hydroxyl group-containing monomer is used as the monomer component of the base polymer (typically an acrylic polymer). When a carboxy group-containing monomer is used as the monomer component of the acrylic polymer, the amount of the carboxy group-containing monomer in the total amount of monomers used in the synthesis of the base polymer is usually About 0.001% by weight or more, suitably about 0.01% by weight or more, preferably about 0.1% by weight or more, more preferably about 0.2% by weight or more, for example 1% by weight or more or 3% by weight or more. The upper limit of the amount of the carboxy group-containing monomer used is appropriately set so as to obtain the desired adhesion properties, and is suitably about 10% by weight or less, preferably about 8% of the total amount of the monomers used to synthesize the base polymer. % by weight or less, more preferably about 6% by weight or less, for example, about 3% by weight or less, or about 1% by weight or less.

When a hydroxyl group-containing monomer is used as a monomer component of a base polymer (typically an acrylic polymer), the amount of the hydroxyl group-containing monomer in the total amount of monomers used to synthesize the base polymer will affect the cohesiveness, anchoring properties, etc. of the adhesive. From the viewpoint of , it is usually about 0.001% by weight or more, suitably about 0.01% by weight or more, preferably about 0.1% by weight or more. The upper limit of the amount of the hydroxyl group-containing monomer used is appropriately set so as to obtain the desired adhesive properties, and is suitably about 5% by weight or less, preferably about 3% by weight, of the total amount of the monomers used to synthesize the base polymer. % or less, more preferably about 1% by weight or less (for example, about 0.5% by weight or less).

Other copolymerizable monomers that can be used in addition to the functional group-containing monomers include vinyl ester monomers such as vinyl acetate and vinyl propionate; vinyl compounds; non-aromatic ring-containing (meth)acrylates such as cyclohexyl (meth)acrylate, t-butylcyclohexyl (meth)acrylate, cyclopentyl (meth)acrylate and isobornyl (meth)acrylate; ethylene, propylene, isoprene, butadiene, Olefin-based monomers such as isobutylene; chlorine-containing monomers such as vinyl chloride and vinylidene chloride; alkoxy group-containing monomers such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; vinyl ether-based monomers such as methyl vinyl ether, ethyl vinyl ether, and isobutyl vinyl ether monomer; and the like. These can be used individually by 1 type or in combination of 2 or more types. When such other copolymerizable monomers are used, the amount used is not particularly limited, and is usually about 30% by weight of the total amount of monomers used to synthesize the base polymer (typically an acrylic polymer). or less (for example, 0 to 30% by weight), preferably about 10% by weight or less (for example, about 3% by weight or less). The technology disclosed herein can also be practiced in a mode in which the monomer components used for synthesizing the base polymer do not substantially contain the above-mentioned other copolymerizable monomers.

Other examples of copolymerizable monomers that can constitute the base polymer (typically an acrylic polymer) include polyfunctional monomers. Specific examples of polyfunctional monomers include 1,6-hexanediol di(meth)acrylate, ethylene glycol di(meth)acrylate, pentaerythritol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, dipentaerythritol hexa Examples include compounds having two or more (meth)acryloyl groups in one molecule, such as (meth)acrylate and methylenebisacrylamide. A polyfunctional monomer can be used individually by 1 type or in combination of 2 or more types. When such a polyfunctional monomer is used, the amount used is not particularly limited, and is usually about 2% by weight or less (more preferably about 1% by weight or less) of the total amount of monomers used to synthesize the base polymer. It is appropriate to

The initiator used for polymerization can be appropriately selected from known or commonly used polymerization initiators. For example, an azo polymerization initiator such as 2,2'-azobisisobutyronitrile can be preferably used. Other examples of polymerization initiators include peroxide-based initiators (persulfates such as potassium persulfate, benzoyl peroxide, hydrogen peroxide, etc.); substituted ethane-based initiators such as phenyl-substituted ethane; compounds; and the like. Still other examples of polymerization initiators include redox initiators based on combinations of peroxides and reducing agents. Examples of such redox initiators include a combination of peroxide and ascorbic acid (a combination of aqueous hydrogen peroxide and ascorbic acid, etc.), a combination of a peroxide and an iron (II) salt (aqueous hydrogen peroxide, etc.). and an iron (II) salt), a combination of a persulfate and sodium hydrogen sulfite, and the like.

Such polymerization initiators can be used singly or in combination of two or more. The amount of the polymerization initiator to be used may be a normal amount. A range can be selected.

A method for obtaining a base polymer (typically an acrylic polymer) having such a monomer composition is not particularly limited, and various polymerization methods such as solution polymerization, emulsion polymerization, bulk polymerization and suspension polymerization are used. obtain. A solution polymerization method can be preferably employed from the viewpoint of transparency, adhesion performance, and the like. As a method of supplying monomers during polymerization, a batch charging method of supplying all the monomer raw materials at once, a continuous supply (dropping) method, a divided supply (dropping) method, or the like can be appropriately adopted. The polymerization temperature can be appropriately selected depending on the type of monomer and solvent used, the type of polymerization initiator, etc., and may be, for example, about 20° C. to 170° C. (typically 40° C. to 140° C.). can. Moreover, the base polymer to be synthesized may be a random copolymer, a block copolymer, a graft copolymer, or the like. From the standpoint of productivity and the like, random copolymers are usually preferred.

Solvents (polymerization solvents) used for solution polymerization according to a preferred embodiment include, for example, aromatic compounds (typically aromatic hydrocarbons) such as toluene and xylene; acetic esters such as ethyl acetate; hexane and the like. Halogenated alkanes such as 1,2-dichloroethane; Lower alcohols such as isopropyl alcohol (e.g., monohydric alcohols having 1 to 4 carbon atoms); tert-butyl methyl Any one solvent selected from ethers such as ether; ketones such as methyl ethyl ketone; and the like, or a mixed solvent of two or more solvents can be used.

The base polymer (acrylic polymer) in the technique disclosed herein has a standard polystyrene equivalent weight average molecular weight (Mw) obtained by GPC (gel permeation chromatography) of about 10×10 ⁴ or more. From the viewpoint of durability, heat resistance, etc., it is preferably about 50×10 ⁴ or more, more preferably about 80×10 ⁴ or more, and even more preferably about 120×10 ⁴ or more. In addition, the above Mw is suitably about 500×10 ⁴ or less, preferably about 300×10 ⁴ or less, more preferably about 250×10 ⁴ from the viewpoint of coatability when forming the pressure-sensitive adhesive layer. Below, more preferably about 200×10 ⁴ or less.

Specifically, the above Mw can be measured under the following conditions using a GPC measuring device, trade name "HLC-8120GPC" (manufactured by Tosoh Corporation).
[Measurement conditions of GPC]
Sample concentration: 0.2% by weight (tetrahydrofuran solution)
Sample injection volume: 100 μL
Eluent: Tetrahydrofuran (THF)
Flow rate (flow rate): 0.8 mL/min Column temperature (measurement temperature): 40°C
Column: manufactured by Tosoh Corporation, G7000H _XL + GMH _XL + GMH _XL
Column size: 7.8 mmφ x 30 cm each, total 90 cm
Detector: differential refractometer (RI)
Standard sample: Polystyrene

(Ionic compound)
The adhesive layer disclosed herein is characterized by containing an ionic compound. The ionic compound improves the conductivity of the pressure-sensitive adhesive layer as a conductive component. For example, one or more selected from alkali metal salts, organic cation-anion salts and the like are preferably used. Organic cation-anion salts are more preferred from the viewpoint of anchoring properties.

(alkali metal salt)
As alkali metal salts, organic salts and inorganic salts of alkali metals can be used. Lithium, sodium, and potassium ions are examples of alkali metal ions that constitute the cation portion of the alkali metal salt. Among these alkali metal ions, lithium ions are preferred.

The anion portion of the alkali metal salt may be composed of an organic substance or may be composed of an inorganic substance. Examples of the anion part constituting ^the organic salt include CH ₃ COO ⁻ , CF ₃ COO − , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , C ₄ F ₉ SO ₃ ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ )(CF ₃ CO)N ⁻ , (FSO ₂ ) ₂ N ⁻ , ⁻ O ₃ S(CF ₂ ) ₃ SO ₃ ⁻ , PF ₆ ⁻ , CO ₃ ^2- and the following general formulas (1) to (4):
(1) (C _n F _2n+1 SO ₂ ) ₂ N ⁻ (where n is an integer of 1 to 10);
(2) CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ (where m is an integer of 1 to 10);
(3) ^— O ₃ S(CF ₂ ) _l SO ₃ ^— (where l is an integer of 1 to 10);
(4) (C _p F _2p+1 SO ₂ )N ⁻ (C _q F _2q+1 SO ₂ ) (where p and q are integers of 1 to 10); Ionic compounds in which the anion part contains a fluorine atom are preferably used because of their good ion dissociation properties. Examples of inorganic anion moieties include Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , AsF ₆ ⁻ , SbF ₆ ⁻ , NbF ₆ ⁻ , TaF ₆ ⁻ , (CN) ₂ N ⁻ and the like are used. As the anion moiety, (perfluoroalkylsulfonyl)imides such as (CF ₃ SO ₂ ) ₂ N ^- and (C ₂ F ₅ SO ₂ ) ₂ N ^- are preferred, and represented by (CF ₃ SO ₂ ) ₂ N ^- (Trifluoromethanesulfonyl)imide is particularly preferred.

Specific examples of alkali metal organic salts include sodium acetate, sodium alginate, sodium ligninsulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, Li(CF ₃ SO ₂ ) _{2N ,} Li( _{C2F5SO2 ) 2N} , Li _{( C4F9SO2 ) 2N ,} Li( _{CF3SO2 ) 3C} , _KO3S ( _CF2 ) _3SO3K , _{LiO3S ( CF2} ) _3SO3K etc. are mentioned. Among _them , _LiCF3SO3 , Li( _{CF3SO2 ) 2N , Li} ( _{C2F5SO2 ) 2N} , Li( _C4F9SO2 ) _2N , _Li ( _{CF3SO2 ) 3} C and the like are preferred, and fluorine-containing lithium imide salts such as Li(CF ₃ SO ₂ ) ₂ N, Li(C ₂ F ₅ SO ₂ ) ₂ N, and Li(C ₄ F ₉ SO ₂ ) ₂ N are more preferred, and ( Perfluoroalkylsulfonyl)imide lithium salts are particularly preferred.
Inorganic salts of alkali metals include lithium perchlorate and lithium iodide.
One of the alkali metal salts may be used alone, or two or more may be used in combination.

(organic cation-anion salt)
The term “organic cation-anion salt” used in the technology disclosed herein refers to an organic salt, the cation component of which is composed of an organic substance, the anion component of which may be an organic substance, It may be inorganic.

Specific examples of the cation components constituting the organic cation-anion salt include pyridinium cations, piperidinium cations, pyrrolidinium cations, cations having a pyrroline skeleton, cations having a pyrrole skeleton, imidazolium cations, tetrahydropyrimidinium cations, cation, dihydropyrimidinium cation, pyrazolium cation, pyrazolinium cation, tetraalkylammonium cation, trialkylsulfonium cation, tetraalkylphosphonium cation, and the like.

The anion component of the organic cation-anion salt includes, for example, Cl ⁻ , Br ⁻ , I ⁻ , AlCl ₄ ⁻ , Al ₂ Cl ₇ ⁻ , BF ₄ ⁻ , PF ₆ ⁻ , ClO ₄ ⁻ , NO ₃ ⁻ , CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₃ C ⁻ , AsF ₆ ⁻ , SbF ₆ − , NbF ₆ ^{− ,} TaF ₆ ⁻ , (CN) ₂ N ⁻ , C ₄ F ₉ SO ₃ ⁻ , C ₃ F ₇ COO ⁻ , (CF ₃ SO ₂ )(CF ₃ CO)N ⁻ , (FSO ₂ ) ₂ N ⁻ , ⁻ O ₃ S(CF ₂ ) ₃ SO ₃ ^- and the following general formulas (1) to (4):
(1) (C _n F _2n+1 SO ₂ ) ₂ N ⁻ (where n is an integer of 1 to 10);
(2) CF ₂ (C _m F _2m SO ₂ ) ₂ N ⁻ (where m is an integer of 1 to 10);
(3) ^— O ₃ S(CF ₂ ) _l SO ₃ ^— (where l is an integer of 1 to 10);
(4) (C _p F _2p+1 SO ₂ )N ⁻ (C _q F _2q+1 SO ₂ ) (where p and q are integers of 1 to 10); An ionic compound containing a fluorine atom as an anion component is preferably used because of its good ion dissociation. The number of carbon atoms in the perfluoroalkyl group of the anion component is preferably 1 to 3, more preferably 1 or 2. These ionic compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

(Other ionic compounds)
In addition to the alkali metal salts and organic cation-anion salts described above, inorganic salts such as ammonium chloride, aluminum chloride, copper chloride, ferrous chloride, ferric chloride, and ammonium sulfate may also be used as the ionic compound. can. The ionic compounds disclosed herein also include what are commonly referred to as ionic surfactants. Ionic surfactants include quaternary ammonium salts, phosphonium salts, sulfonium salts, pyridinium salts, cationic surfactants having cationic functional groups such as amino groups; carboxylic acids, sulfonates, sulfates, phosphates, phosphites, etc. Zwitterionic surfactants such as sulfobetaine and its derivatives, alkylbetaine and its derivatives, imidazoline and its derivatives, alkylimidazolium betaine and its derivatives; . The organic cation-anion salts may be used singly or in combination of two or more.

Ionic compounds include ionic solids and ionic liquids, and ionic liquids are preferably used. Ionic liquids tend to move in the adhesive layer and are easily dispersed uniformly in the layer, but they are unevenly distributed due to chemical action and the like, and can affect the required properties (typically anchoring properties) of the adhesive. When an ionic liquid is used as the ionic compound, the effects of the technology disclosed herein tend to be exhibited favorably. When the polymer A is an acrylic polymer, it is particularly preferred to use an ionic liquid as the ionic compound.

The term "ionic liquid" refers to a molten salt that exhibits a liquid state at 40°C or lower. Ionic liquids can be easily added to, dispersed in, or dissolved in pressure-sensitive adhesives in the temperature range in which they exhibit a liquid state, compared to solid salts. Furthermore, since the ionic liquid has no vapor pressure (non-volatile), it does not disappear over time, and has the characteristic that antistatic properties can be continuously obtained. The ionic liquid used in the technology disclosed herein is preferably a molten salt that is liquid at room temperature (25° C.) or lower. Among the ionic compounds described above, organic cation-anion salts (ionic liquids of organic cation-anion salts) that are liquid at 40°C or lower are preferred, and organic cation-anion salts that are liquid at room temperature (25°C) or lower. (Organic cation-anion salt ionic liquid) is more preferred.

The content of the ionic compound in the adhesive layer is 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer (polymer A, eg acrylic polymer). By setting the content of the ionic compound to 5 parts by weight or more, the conductivity of the pressure-sensitive adhesive layer is improved. Also, by setting the content of the ionic compound to 20 parts by weight or less, deterioration in heat durability can be suppressed. Considering the balance of conductivity and the like, the content of the ionic compound can be, for example, approximately 5 parts by weight or more with respect to 100 parts by weight of the base polymer. The upper limit of the content of the ionic compound is preferably about 17 parts by weight or less, and may be, for example, about 15 parts by weight or less with respect to 100 parts by weight of the base polymer. It may be 10 parts by weight or less.

(Adhesive composition)
In the technology disclosed herein, the form of the pressure-sensitive adhesive composition used for forming the pressure-sensitive adhesive layer is not particularly limited. For example, an adhesive composition containing an adhesive component in an organic solvent (solvent-type adhesive composition), an adhesive composition in which an adhesive component is dispersed in an aqueous solvent (water-dispersed adhesive composition, typically water-based emulsion type pressure-sensitive adhesive composition), solvent-free pressure-sensitive adhesive composition (e.g., pressure-sensitive adhesive composition of the type that is cured by irradiation with active energy rays such as ultraviolet rays and electron beams, hot-melt pressure-sensitive adhesive composition things), etc. The technique disclosed herein can be preferably implemented in a mode provided with an adhesive layer formed from a solvent-type adhesive composition. The organic solvent contained in the solvent-based pressure-sensitive adhesive composition may be, for example, a single solvent consisting of any one of toluene, xylene, ethyl acetate, hexane, cyclohexane, methylcyclohexane, heptane and isopropyl alcohol. It may be a mixed solvent containing as a main component.

In the technique disclosed herein, the adhesive composition (preferably a solvent-based adhesive composition) used for forming the adhesive layer includes polymer A as a base polymer contained in the composition (typically It is possible to preferably employ those configured so that the acrylic polymer) can be appropriately crosslinked. As a specific cross-linking means, a cross-linking base point is introduced into the base polymer by copolymerizing a monomer having an appropriate functional group (hydroxyl group, carboxyl group, etc.), and a cross-linked structure is formed by reacting with the functional group. A method of adding a compound (cross-linking agent) capable of forming a cross-linking agent to the base polymer and reacting it can be preferably employed.

Examples of cross-linking agents include isocyanate-based cross-linking agents, epoxy-based cross-linking agents, oxazoline-based cross-linking agents, aziridine-based cross-linking agents, melamine-based cross-linking agents, carbodiimide-based cross-linking agents, hydrazine-based cross-linking agents, amine-based cross-linking agents, and imine-based cross-linking agents. agents, peroxide-based cross-linking agents (eg, benzoyl peroxide), metal chelate-based cross-linking agents (typically polyfunctional metal chelates), metal alkoxide-based cross-linking agents, metal salt-based cross-linking agents, and the like. A crosslinking agent can be used individually by 1 type or in combination of 2 or more types. Among them, isocyanate-based cross-linking agents, epoxy-based cross-linking agents, peroxide-based cross-linking agents, and metal chelate-based cross-linking agents are preferable. For example, when an acrylic polymer is used as the base polymer, an isocyanate-based cross-linking agent or a peroxide-based cross-linking agent is preferable, and a combined use of an isocyanate-based cross-linking agent and a peroxide-based cross-linking agent is more preferable.

The amount of the cross-linking agent to be used can be appropriately selected depending on the composition and structure (molecular weight, etc.) of the base polymer (for example, acrylic polymer), the application of the pressure-sensitive adhesive layer-attached optical film, and the like. Normally, the amount of the cross-linking agent used relative to 100 parts by weight of the base polymer is suitably about 0.01 parts by weight or more, and from the viewpoint of increasing the cohesive strength of the pressure-sensitive adhesive, preferably about 0.02 parts by weight or more. , and more preferably about 0.03 parts by weight or more (for example, 0.1 parts by weight or more). The upper limit of the amount of the cross-linking agent used is usually about 10 parts by weight or less per 100 parts by weight of the base polymer, and from the viewpoint of wettability to the adherend, etc., preferably about 5 parts by weight. Below, more preferably about 3 parts by weight or less, still more preferably about 1 part by weight or less.

Various additives can be added to the pressure-sensitive adhesive composition as necessary. Examples of such additives include surface lubricants, leveling agents, plasticizers, softeners, fillers, antioxidants, preservatives, light stabilizers, ultraviolet absorbers, polymerization inhibitors, cross-linking accelerators, silane coupling agents, agents and the like. In addition to the ionic compound, the pressure-sensitive adhesive layer may or may not optionally contain a conductive component other than the ionic compound. In addition, a known or commonly used tackifying resin or release control agent may be blended in a pressure-sensitive adhesive composition having an acrylic polymer as a base polymer. Furthermore, the pressure-sensitive adhesive layer disclosed herein may or may not contain an alkylene oxide compound such as polypropylene glycol for the purpose of adjusting removability and hygroscopicity. Furthermore, when synthesizing the adhesive polymer by emulsion polymerization, an emulsifier or a chain transfer agent (also referred to as a molecular weight modifier or polymerization degree modifier) is preferably used. The content of these optional additives can be appropriately determined according to the purpose of use. The amount of the optional additive used is usually about 5 parts by weight or less, preferably about 3 parts by weight or less (for example, about 1 part by weight or less) per 100 parts by weight of the base polymer.

(Method for forming adhesive layer)
The pressure-sensitive adhesive layer in the technology disclosed herein is formed by, for example, a method of directly applying the above-described pressure-sensitive adhesive composition onto an antistatic layer provided on an optical film and drying or curing (direct method). can do. Alternatively, the pressure-sensitive adhesive composition is applied to the surface (release surface) of the release liner and dried or cured to form a pressure-sensitive adhesive layer on the surface. It may be formed by a method (transfer method) in which the pressure-sensitive adhesive layer is transferred by attaching it to the surface of the prevention layer. Various methods such as a roll coating method, a gravure coating method, and the like can be appropriately employed for applying (typically applying) the pressure-sensitive adhesive composition. Drying of the pressure-sensitive adhesive composition can be performed under heating, if necessary. Ultraviolet rays, laser rays, α rays, β rays, γ rays, X rays, electron beams, and the like can be appropriately employed as means for curing the pressure-sensitive adhesive composition.

(Surface resistance value of adhesive layer)
The surface resistance value of the pressure-sensitive adhesive layer is suitably about 1×10 ¹² Ω/□ or less from the viewpoint of antistatic properties. When a pressure-sensitive adhesive layer having a surface resistance value limited to a predetermined value or less is applied to a liquid crystal panel (for example, an in-cell type liquid crystal panel), the occurrence of static electricity unevenness is favorably prevented due to its conductivity. From the viewpoint of touch sensor sensitivity and durability, the lower limit of the surface resistance value is preferably about 1×10 ⁸ Ω/□ or more. From the above point of view, for example, when applied to an on-cell type liquid crystal cell to be described later, the surface resistance value is preferably about 1×10 ¹⁰ Ω/□ to 1×10 ¹² Ω/□. Further, when applied to a semi-in-cell type liquid crystal cell described later, the surface resistance value is preferably about 1×10 ⁹ Ω/□ to 1×10 ¹² Ω/□. Furthermore, when applied to an in-cell liquid crystal cell described later, the surface resistance value is preferably about 1×10 ⁸ Ω/square to 1×10 ¹⁰ Ω/square. It is more preferably 1×10 ⁹ Ω/□ to 1×10 ¹⁰ Ω/□.

The surface resistance value of the pressure-sensitive adhesive layer was measured with respect to the surface of the pressure-sensitive adhesive layer formed on the release liner in an atmosphere of 23°C and 50% RH, according to JIS K 6911, with an applied voltage of 250 V and an applied time of 10 seconds. measured under the conditions of As the resistivity meter, a commercially available resistivity meter (for example, trade name “Hiresta UP MCP-HT450” manufactured by Mitsubishi Chemical Analytic Co., Ltd.) can be used. A similar method is adopted in the examples described later.

(Thickness of adhesive layer)
Although not particularly limited, the thickness of the pressure-sensitive adhesive layer can be, for example, about 1 μm or more, and usually about 3 μm or more is suitable. From the viewpoint of antistatic properties, durability, and ensuring a contact area with the conduction path when the conduction path is provided on the side surface, the thickness of the pressure-sensitive adhesive layer is preferably about 5 μm or more, more preferably about 7 μm or more, and further Preferably, it is about 10 μm or more. The thickness can be, for example, about 100 μm or less, and is usually preferably about 50 μm or less (eg, about 35 μm or less).

<Antistatic layer>
The antistatic layer disclosed herein comprises a conductive polymer and polymer B. Polymer B may typically function as a binder in the antistatic layer. The antistatic layer is disposed between the optical film and the pressure-sensitive adhesive layer, and not only functions as an anchor layer that enhances the adhesion of the pressure-sensitive adhesive layer to the optical film, but also has a predetermined electrical conductivity. It plays a role of increasing the conductivity of the layered optical film.

(Conductive polymer)
The technology disclosed herein uses a conductive polymer as the antistatic agent contained in the antistatic layer. By using a conductive polymer, an antistatic layer excellent in optical properties, appearance, antistatic effect, and stability of the antistatic effect during heating or humidification can be preferably obtained. Conductive polymers include polymers such as polyaniline, polythiophene, polypyrrole, polyquinoxaline, polyethyleneimine, and polyallylamine. Such conductive polymers may be used singly or in combination of two or more. Among them, polyaniline (aniline-based polymer) and polythiophene (thiophene-based polymer) are preferable.

Polythiophene and polyaniline are examples of conductive polymers that can be preferably employed in the technology disclosed herein. As used herein, polythiophene refers to a polymer of unsubstituted or substituted thiophene. One preferred example of the substituted thiophene polymer in the technology disclosed herein is poly(3,4-ethylenedioxythiophene).

As the conductive polymer, organic solvent-soluble, water-soluble, or water-dispersible polymers can be used without particular limitation. In one preferred embodiment, the conductive polymer is used in the form of an aqueous solution or dispersion to form the antistatic layer. As a result, the coating liquid composed of the antistatic layer-forming composition can be in the form of an aqueous solution or an aqueous dispersion, so that the risk of deterioration of the optical film due to the organic solvent can be avoided. Conductive polymers such as polyaniline and polythiophene are preferably used because they are easily formed into aqueous solutions or aqueous dispersions. Among them, polythiophene is more preferable. The aqueous solution or aqueous dispersion may contain an aqueous solvent in addition to water. For example, methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, n-amyl alcohol, isoamyl alcohol, sec-amyl alcohol, tert-amyl alcohol, 1-ethyl-1 One or more alcohols such as -propanol, 2-methyl-1-butanol, n-hexanol and cyclohexanol can be used in the form of a mixed solvent (aqueous solvent) with water.

The aqueous solution or aqueous dispersion of the conductive polymer is, for example, a conductive polymer having a hydrophilic functional group (can be synthesized by a method such as copolymerizing a monomer having a hydrophilic functional group in the molecule) in water. It can be prepared by dissolving or dispersing. Examples of the hydrophilic functional groups include sulfo group, amino group, amide group, imino group, hydroxyl group, mercapto group, hydrazino group, carboxy group, quaternary ammonium group, sulfate ester group (--O--SO ₃ H), phosphorus An acid ester group (eg, —O—PO(OH) ₂ ) is exemplified. Such hydrophilic functional groups may form salts. Examples of commercially available polythiophene aqueous solutions include the product name "Denatron" series manufactured by Nagase Chemtech. Further, as a commercially available product of polyaniline sulfonic acid aqueous solution, Mitsubishi Rayon Co., Ltd. trade name "aqua-PASS" is exemplified.

In a preferred embodiment of the technology disclosed herein, a polythiophene aqueous solution is used for preparing the composition for forming an antistatic layer. The use of an aqueous polythiophene solution containing polystyrene sulfonate (PSS) (which may be in the form of polythiophene to which PSS is added as a dopant) is preferred. Such aqueous solutions may contain polythiophene:PSS in a weight ratio of 1:1 to 1:10. The total content of polythiophene and PSS in the aqueous solution can be, for example, about 1 to 5% by weight.

In the antistatic layer-forming composition prepared using a liquid containing a conductive polymer such as polythiophene (typically an aqueous solution), the content of the conductive polymer is about 0.005% by weight or more is suitable, preferably about 0.01% by weight or more. The upper limit of the content of the conductive polymer in the antistatic layer-forming composition is, for example, about 5% by weight or less, preferably about 3% by weight or less, more preferably about 1% by weight or less, and even more preferably about 1% by weight or less. It is 0.7% by weight or less. In the antistatic layer obtained using the antistatic layer-forming composition, the content of the conductive polymer is suitably about 1% by weight or more, preferably about 3% by weight or more, from the viewpoint of antistatic. More preferably about 5% by weight or more, still more preferably about 7% by weight or more, and particularly preferably about 10% by weight or more. The upper limit of the content of the conductive polymer in the antistatic layer is preferably about 90% by weight or less.

(Polymer B)
The antistatic layer disclosed herein is also characterized by comprising Polymer B. Polymer B may be defined as a polymer different from the conductive polymer. By including the polymer B together with the above conductive polymer, the antistatic layer can achieve film formability, adhesion to the optical film, and the like. Moreover, the polymer B contained in the antistatic layer has a functional group b that interacts with the functional group a of the polymer A contained as the base polymer in the pressure-sensitive adhesive layer. This improves the adhesion between the antistatic layer and the adhesive layer.

Polymer B is also characterized by having 10 mol % or less of polyether units in its molecule. This suppresses the deterioration of the anchoring ability of the pressure-sensitive adhesive layer to the antistatic layer. From TOF-SIMS analysis, when polymer B in the antistatic layer has a predetermined amount or more of polyether units, the ionic compound contained in the adhesive layer migrates to the interface with the antistatic layer; in the antistatic layer It has been confirmed that the ionic compound in the pressure-sensitive adhesive layer does not move when the polyether unit of the polymer B is less than a predetermined value, and the polyether unit of the polymer B reduces the anchoring property. Conceivable. It is believed that by limiting the amount of polyether units in the polymer B having the functional group b to a predetermined amount or less, the decrease in anchoring ability can be effectively suppressed. Since this effect can be achieved without reducing the amount of the ionic compound in the pressure-sensitive adhesive layer, it is compatible with the improvement of antistatic properties. Although this point is not particularly limitedly interpreted, for example, the following considerations are possible. That is, the polyether units of the polymer B in the antistatic layer exist in a state of being incorporated in the molecule by copolymerization or the like, and are not free in the layer. Polymer B improves adhesion with the adhesive layer due to the presence of the functional group b at or near the interface with the adhesive layer in the antistatic layer, while those having polyether units thereby improve adhesion. It is thought that it attracts ionic compounds in the agent layer and causes a decrease in anchoring properties. Here, when the polyether unit is separated from the polymer B having the functional group b, it does not hinder the adhesion improvement by the functional group b (Examples 6 and 7 described later). In such a form, the polyether unit-containing compound migrates across the interface into the adhesive layer, or the ionic compound in the adhesive layer crosses the interface and converts the polyether unit-containing compound into the adhesive layer. It is thought that these compounds are not unevenly distributed near the interface between the pressure-sensitive adhesive layer and the antistatic layer.

The polyether unit in the polymer B molecule is preferably about 5 mol % or less, more preferably about 3 mol % or less, still more preferably about 1 mol % or less (for example, 0.1 mol % or less) from the viewpoint of suppressing deterioration of anchoring properties. The technique disclosed herein can be preferably carried out in a mode in which the polymer B contains substantially no polyether units in the molecule. Here, "the polymer B does not substantially contain polyether units in the molecule" means that the polyether unit in the polymer B molecule is 0.1 mol % or less. The above polyether units are introduced into polymer B, for example, by polymerizing or copolymerizing monomers having polyether units. Therefore, in the synthesis of polymer B, by limiting the amount of monomers having polyether units, it is possible to obtain polymer B in which the amount of polyether units in the molecule is limited.

The mol% of the polyether units in the polymer B is the molar ratio [mol%] of the polyether units in the polymer B when the repeating unit constituting the polymer B is regarded as one molecule. In other words, the above mol % of polyether units is the ratio of the number of polyether units as repeating units to the total number of repeating units constituting polymer B.

Moreover, the polymer B contained in the antistatic layer has a functional group b that interacts with the functional group a of the polymer A contained in the pressure-sensitive adhesive layer. The functional group b is not particularly limited as long as it interacts with the functional group a. The functional group b can be selected from, for example, one of the group consisting of a carboxy group, an acid anhydride group, a hydroxyl group and a thiol group, or the group consisting of an oxazoline group and an isocyanate group. As the functional group b, one type may be employed alone, or two or more types may be used. Among them, the functional group b is preferably at least one functional group selected from the group consisting of oxazoline groups and isocyanate groups. An oxazoline group is particularly preferred from the viewpoint of film formability. In addition, the oxazoline group as the functional group b reacts with the functional group a of the polymer A in the pressure-sensitive adhesive layer at a relatively low temperature to easily improve the anchoring property. The functional group b is typically introduced into the polymer B by polymerizing or copolymerizing a monomer containing the functional group b.

When functional group b (e.g. oxazoline group) in polymer B (e.g. oxazoline group-containing polymer) is introduced into polymer B by polymerizing or copolymerizing a functional group b-containing monomer (e.g. oxazoline group-containing monomer), The ratio of the functional group b-containing monomer to the total amount of monomers used for synthesis of polymer B (which may be a copolymerization ratio) [mol%] is not particularly limited, and is, for example, about 10 mol% or more, usually about 30 mol%. It is appropriate to be above. In a preferred embodiment, from the viewpoint of improving the anchoring property of the pressure-sensitive adhesive layer, the ratio [mol%] of the functional group b-containing monomer to the total amount of monomers used in the synthesis of the polymer B is approximately 50 mol% or more, more preferably approximately 70 mol. % or more, more preferably about 80 mol % or more, for example about 90 mol % or more. Polymer B may be substantially a homopolymer of monomers containing functional group b. The ratio (copolymerization ratio) [mol%] of the functional group b-containing monomer may be less than about 95 mol%, or may be less than about 90 mol%, with emphasis on other properties of polymer B (for example, properties as a binder). . In another aspect, the ratio [mol%] of the functional group b-containing monomer may be less than 70 mol%, or less than about 50 mol% (for example, less than 40 mol%).

Polymer B used in the antistatic layer is not particularly limited as long as it contains 10 mol % or less of the above polyether unit and has the above functional group b, and various polymers can be used. Specific examples of polymer B include oxazoline group-containing polymers, urethane-based polymers, acrylic polymers, polyester-based polymers, amide-based polymers, cellulose-based polymers, vinyl alcohol-based polymers, epoxy group-containing polymers, vinylpyrrolidone-based polymers, and styrene-based polymers. A polymer etc. are mentioned. These may be used individually by 1 type, and may be used in combination of 2 or more type. Among them, oxazoline group-containing polymers, urethane-based polymers, acrylic polymers and polyester-based polymers are preferred, and oxazoline group-containing polymers are particularly preferred.

In a preferred embodiment, polymer B is an oxazoline group-containing polymer. The oxazoline group-containing polymer can be used singly or in combination of two or more. Oxazoline group-containing polymers that are soluble or dispersible in water are preferred. The oxazoline group may be any of a 2-oxazoline group, a 3-oxazoline group and a 4-oxazoline group, and for example, those having a 2-oxazoline group are preferably used.

Examples of the oxazoline group-containing polymer include those containing a (meth)acrylic skeleton or styrene skeleton as a main chain and having an oxazoline group in the side chain of the main chain. An oxazoline group-containing polymer according to a preferred embodiment may be an oxazoline group-containing (meth)acrylic polymer that includes a main chain composed of a (meth)acrylic skeleton and has oxazoline groups in the side chains of the main chain. Such an oxazoline group-containing polymer may have a polyoxyalkylene group or other functional groups in addition to the oxazoline group, as long as the polyether unit content is limited to 10 mol % or less.

The molecular weight of the oxazoline group-containing polymer can be appropriately set based on the purpose, required properties, and the like. The upper limit of the molecular weight of the oxazoline group-containing polymer is suitably about 100×10 ⁴ or less, preferably about 50×10 ⁴ or less, more preferably about 10×10 ⁴ or less, from the viewpoint of coatability and the like. , more preferably about 5×10 ⁴ or less. The above Mn is a value converted to standard polystyrene based on GPC.

The content of polymer B (preferably oxazoline group-containing polymer) in the antistatic layer is suitably about 3% by weight or more. From the viewpoint of anchoring properties, the content of polymer B is preferably about 5% by weight or more, more preferably about 8% by weight or more, and even more preferably about 10% by weight or more. The upper limit of the content of the polymer B is usually about 99% by weight or less, suitably about 90% by weight or less, preferably about 80% by weight, in consideration of the action of other components such as the conductive polymer. % or less, more preferably about 70% by weight or less, and even more preferably about 60% by weight or less.

The antistatic layer in the technology disclosed herein may contain a conductive component other than the conductive polymer. Examples of such a conductive component include the ionic compound contained in the pressure-sensitive adhesive layer, and other conductive components that may be contained in the pressure-sensitive adhesive layer and that do not correspond to conductive polymers. These can be used individually by 1 type or in combination of 2 or more types. In the technology disclosed herein, the content of conductive components other than the conductive polymer in the antistatic layer can be set within a range that does not impair the effects of the invention. Its content in the antistatic layer is usually about 5% by weight or less, preferably about 3% by weight or less (for example, about 1% by weight or less, typically 0.3% by weight or less). be. The technique disclosed herein can be preferably carried out in a mode in which the antistatic layer does not substantially contain conductive components other than the conductive polymer.

The antistatic layer may also optionally comprise a polymer C different from the conductive polymer, polymer B. Polymer C is, for example, a component that functions as a binder in the antistatic layer and does not have the above functional group b, or polymer C does not have functional group b and is an oxazoline group-containing polymer, urethane-based One or two of polymers, acrylic polymers, polyester polymers, polyether polymers, cellulose polymers, vinyl alcohol polymers, epoxy group-containing polymers, vinylpyrrolidone polymers, styrene polymers, polyethylene glycol, pentaerythritol, etc. It can be more than Preferred examples of polymer C include urethane-based polymers (typically polyurethane). The content of polymer C in the antistatic layer can be set within a range that does not impair the effects of the invention.

Additives can be added to the antistatic layer as needed. Additives include leveling agents, antifoaming agents, thickeners, antioxidants, and the like. The proportion of these additives in the antistatic layer is usually about 50% by weight or less, preferably about 30% by weight or less (for example, about 10% by weight or less).

(Method for forming antistatic layer)
The antistatic layer is formed by applying a liquid composition (coating material for forming an antistatic layer) in which the resin component and optional additives are dispersed or dissolved in an appropriate solvent to a film substrate (optical film). It can be preferably formed by a method including applying. For example, a method of applying the above coating material to the first surface of the film base material, drying it, and optionally performing a curing treatment (heat treatment, ultraviolet treatment, etc.) can be preferably employed. The solid content concentration (NV) of the coating material can be, for example, 5% by weight or less (typically 0.05 to 5% by weight), and usually 1% by weight or less (typically 0.10% by weight). ~1% by weight). When forming a thin antistatic layer, the NV of the coating material is preferably 0.05 to 0.50% by weight (eg, 0.10 to 0.30% by weight). By using such a low NV coating material, a more uniform antistatic layer can be formed.

(Surface resistance value of antistatic layer)
The surface resistance value of the antistatic layer is suitably about 1×10 ¹² Ω/□ or less from the viewpoint of antistatic properties. When an antistatic layer whose surface resistance value is limited to a predetermined value or less is applied to a liquid crystal panel (for example, an in-cell type liquid crystal panel), the occurrence of static electricity unevenness is prevented based on the conductivity of the antistatic layer in addition to the adhesive layer. be. From the viewpoint of touch sensor sensitivity, the lower limit of the surface resistance value is preferably about 1×10 ⁸ Ω/□ or more. From the above point of view, for example, when applied to an on-cell type liquid crystal cell to be described later, the surface resistance value is preferably about 1×10 ¹⁰ Ω/□ to 1×10 ¹² Ω/□. Further, when applied to a semi-in-cell type liquid crystal cell described later, the surface resistance value is preferably about 1×10 ⁹ Ω/□ to 1×10 ¹² Ω/□. Furthermore, when applied to an in-cell liquid crystal cell described later, the surface resistance value is preferably about 1×10 ⁸ Ω/square to 1×10 ¹⁰ Ω/square. It is more preferably 1×10 ⁸ Ω/□ to 1×10 ⁹ Ω/□.

The surface resistance value of the antistatic layer is applied to the surface of the optical film with the antistatic layer before the adhesive layer is formed, in an atmosphere of 23 ° C. and 50% RH, according to JIS K 6911, with an applied voltage of 10 V and an applied time. Measured under the condition of 10 seconds. The resistivity meter used is the same as that for measuring the surface resistance of the pressure-sensitive adhesive layer. A similar method is adopted in the examples described later.

(Thickness of antistatic layer)
The thickness of the antistatic layer in the technology disclosed herein can be appropriately set according to required properties such as antistatic properties and anchoring properties. The thickness of the antistatic layer is usually about 10 nm or more, and more than 10 nm is suitable. From the viewpoint of improving antistatic properties and obtaining a uniform thickness, the thickness of the antistatic layer is preferably 12 nm or more, more preferably 14 nm or more, still more preferably 15 nm or more, and particularly preferably 20 nm or more (typically 25 nm or more). above, for example, 30 nm or above). Moreover, it is suitable that the thickness of the antistatic layer is about 500 nm or less. By controlling the thickness of the antistatic layer to about 500 nm or less, good optical properties (total light transmittance, etc.) can be easily obtained. From such a viewpoint, the thickness of the antistatic layer is preferably about 100 nm or less, more preferably about 50 nm or less.

<Release liner>
For the optical film with a pressure-sensitive adhesive layer disclosed herein, if necessary, a release liner is attached to the pressure-sensitive adhesive surface for the purpose of protecting the pressure-sensitive adhesive surface (the surface of the pressure-sensitive adhesive layer that is attached to the adherend). It can be provided in a laminated form (in the form of a release liner and an optical film with an adhesive layer). As the substrate constituting the release liner, paper, synthetic resin film, etc. can be used. A synthetic resin film is preferably used because of its excellent surface smoothness. For example, various resin films (for example, polyester film) can be preferably used as the substrate of the release liner. The thickness of the release liner can be, for example, about 5 to 200 μm, and usually about 10 to 100 μm is preferable. The surface of the release liner to be bonded to the pressure-sensitive adhesive layer is coated with a known release agent (e.g., silicone-based, fluorine-based, long-chain alkyl-based, fatty acid amide-based, etc.) or silica powder. Alternatively, antifouling treatment may be applied.

<Other layers, etc.>
In the optical film with an adhesive layer disclosed herein, in addition to the above layers (optical film, adhesive layer, antistatic layer, optional surface treatment layer), easy adhesion between the optical film and the antistatic layer A layer may be provided, and various adhesion-facilitating treatments such as corona treatment and plasma treatment may be applied.

<Application>
When the optical film with an adhesive layer disclosed herein is used as a liquid crystal panel material, the occurrence of static electricity unevenness in the liquid crystal panel can be prevented based on the conductivity of the adhesive layer containing a predetermined amount of ionic compound and the antistatic layer. Highly preventable. Therefore, it is preferably used as an optical film with a pressure-sensitive adhesive layer for liquid crystal cells, liquid crystal panels, and liquid crystal display devices. For example, the optical film with a pressure-sensitive adhesive layer disclosed herein is preferably used for a liquid crystal cell called an in-cell liquid crystal cell, a semi-in-cell liquid crystal cell, an on-cell liquid crystal cell, and a liquid crystal panel comprising the liquid crystal cell, which will be described later. . Moreover, when the optical film with an adhesive layer is used in a touch panel type display device, good touch sensor sensitivity can be maintained. Therefore, it is suitable also as an optical film with an adhesive layer for touch panels. By utilizing the prevention of electrostatic unevenness and the sensitivity of the touch sensor as described above, the optical film with an adhesive layer disclosed herein can be used as a liquid crystal panel with a touch sensor (also referred to as a liquid crystal panel with a touch sensing function), As a result, it is particularly preferably used for a touch panel type liquid crystal display device (also referred to as a liquid crystal display device with a touch sensing function). By applying the technology disclosed herein to the above uses, excellent workability and durability can be obtained based on the improved anchoring property of the pressure-sensitive adhesive layer.

Liquid crystal panels having various structures can be employed as the touch sensor mounted liquid crystal panel as described above. For example, the optical film with a pressure-sensitive adhesive layer disclosed herein is preferably used for a liquid crystal panel called an in-cell type liquid crystal panel or an on-cell type liquid crystal panel. Briefly speaking, an in-cell liquid crystal panel is a liquid crystal cell comprising a liquid crystal layer and two transparent substrates sandwiching the liquid crystal layer. It has the structure provided with the touch sensing electrode part in connection with a touch sensing function. A complete in-cell liquid crystal panel is one in which both the detection electrodes and drive electrodes involved in the touch sensing function are arranged within the liquid crystal cell. A semi-in-cell liquid crystal panel is one in which only one of the detection electrode and the drive electrode is arranged inside the liquid crystal cell, and the other electrode is arranged outside the liquid crystal cell (typically on the outer surface of the transparent substrate). An on-cell type liquid crystal panel is one in which a touch sensor function is arranged on the outer surface of the transparent substrate of the liquid crystal cell. The effect of improving conductivity by the optical film with a pressure-sensitive adhesive layer disclosed herein can be preferably exhibited in an in-cell type that does not have a conductive layer such as an ITO layer on the panel surface. In addition, the effect of the technology disclosed herein (prevention of static electricity unevenness and good touch sensor sensitivity) can be preferably exhibited in an in-cell liquid crystal panel. Therefore, the optical film with a pressure-sensitive adhesive layer disclosed herein is particularly preferably used for an in-cell liquid crystal panel. The optical film with a pressure-sensitive adhesive layer disclosed herein has a configuration in which a touch panel is arranged outside the optical film (for example, a configuration in which a touch panel is provided outside a liquid crystal panel such as an IPS system), or a liquid crystal having such a configuration. It can be used for a display device.

<Structure of liquid crystal panel>
Preferred applications of the pressure-sensitive adhesive layer-attached optical film disclosed herein include, for example, in-cell liquid crystal panels as shown in FIGS. 2 to 6 are schematic cross-sectional views showing configuration examples of in-cell liquid crystal panels. The in-cell liquid crystal panel 100 shown in FIG. 2 includes a liquid crystal cell (in-cell liquid crystal cell) 120 and an optical film 110 with an adhesive layer arranged on the viewing side of the liquid crystal cell 120 . As the optical film 110 with an adhesive layer, the optical film with an adhesive layer disclosed herein is used.

The liquid crystal cell 120 includes a liquid crystal layer 125 containing liquid crystal molecules, and a first transparent substrate 141 and a second transparent substrate 142 arranged to sandwich the liquid crystal layer 125 . Also, the liquid crystal cell 120 includes a touch sensing electrode part 130 between the first transparent substrate 141 and the second transparent substrate 142 . The touch sensing electrode unit 130 has detection electrodes 131 and drive electrodes 132 . Here, the detection electrode is a touch detection (reception) electrode, and functions as a capacitance sensor. The detection electrodes are also called touch sensor electrodes.

In the touch sensing electrode unit 130, when the liquid crystal cell 120 is viewed as a plane, the detection electrodes 131 and the drive electrodes 132 are formed independently in stripes in the X-axis direction and the Y-axis direction of the plane, Both form patterns that intersect each other at right angles. The pattern that the touch sensor electrode 130 can form is not limited to this, and the detection electrode 131 and the drive electrode 132 can be formed to have various patterns as described later.

In the in-cell liquid crystal panel 100, the adhesive layer-attached optical film 110 arranged on the viewing side of the liquid crystal cell 120 has the adhesive layer 112 attached on the outer surface of the first transparent substrate 141 of the liquid crystal cell 120. there is In other words, the optical film 110 with an adhesive layer is arranged and fixed on the outer surface of the first transparent substrate 141 without interposing a conductive layer. Hereinafter, for the purpose of distinguishing from the optical film with an adhesive layer disposed on the side opposite to the viewing side in the liquid crystal panel, the optical film and the adhesive layer, the optical film 110 with an adhesive layer, the optical film 111 and the adhesive layer 112 may be referred to as a first pressure-sensitive adhesive layer-attached optical film, a first optical film, and a first pressure-sensitive adhesive layer, respectively. The optical film 111 in the pressure-sensitive adhesive layer-attached optical film 110 is typically a polarizing film, and is arranged on the viewing side of the liquid crystal layer 125 such that the transmission axis (or absorption axis) of the polarizer is orthogonal. . A surface treatment layer 114 is formed on the back side of the optical film 110 with an adhesive layer.

On the other hand, in the in-cell type liquid crystal panel 100, an optical film 150 with an adhesive layer is arranged on the side opposite to the side where the optical film 110 with an adhesive layer is arranged. The optical film 151 constituting the optical film 150 with an adhesive layer is adhered to the outer surface of the second transparent substrate 142 of the liquid crystal cell 120 via the adhesive layer 152 . The optical film 151 is typically a polarizing film, and is arranged on the back side of the liquid crystal layer 125 so that the transmission axes (or absorption axes) of the polarizers thereof are perpendicular to each other. Hereinafter, for the purpose of distinguishing the adhesive layer-attached optical film 150, the optical film 151, and the adhesive layer 152 from those arranged on the viewing side of the liquid crystal panel, the second adhesive layer-attached optical film and the second optical film are described below, respectively. Sometimes referred to as a film and a second adhesive layer.

Further, in the in-cell liquid crystal panel 100, a conductive structure 170 made of a conductive material is provided on the side surface of the antistatic layer 113 and the adhesive layer 112 of the optical film 110 with an adhesive layer. This allows the potential to escape from the side surfaces of the antistatic layer 113 and the adhesive layer 112 to other locations, thereby reducing or preventing charging due to static electricity. The conductive structure 170 may be provided on the entire side surface (end surface) of the antistatic layer 113 and the adhesive layer 112, or may be provided on a part of the side surface. When the conductive structure 170 is partially provided, the total area of the side surfaces of the antistatic layer 113 and the pressure-sensitive adhesive layer 112 is about 1% or more, preferably about 3% or more, more preferably about 3% or more, in order to ensure conduction on the side surfaces. The conductive structure 170 can be provided at an area ratio of about 10% or more, more preferably about 50% or more. In addition, in the configuration example shown in FIG. 2, the conductive structure 171 is also provided on the side surfaces of the optical film 111 and the surface treatment layer 114 .

The in-cell liquid crystal panel 200 shown in FIG. 3 is a modification of the configuration shown in FIG. 2 differs from the configuration shown in FIG. That is, the touch sensing electrode section 230 having the detection electrodes 231 and the drive electrodes 232 is arranged on the backlight side (back side) of the liquid crystal layer 225 . The in-cell liquid crystal panel 300 shown in FIG. 4 is also a modification of the configuration shown in FIG. 2, and differs from the configuration shown in FIG. different. The in-cell liquid crystal panel 400 shown in FIG. 5 is a combination of the configurations shown in FIGS. The configuration differs from that shown in FIG. 2 in that the electrode section 430 is arranged on the backlight side (back side) of the liquid crystal layer 425 .

Also, the in-cell liquid crystal panel 500 shown in FIG. 6 differs from the configuration shown in FIG. . Specifically, in the in-cell liquid crystal panel 500, the detection electrodes 531 are arranged between the liquid crystal layer 525 and the first transparent substrate 541, and the drive electrodes 532 are arranged between the liquid crystal layer 525 and the second transparent substrate 542. are placed in Other configurations of the modified examples shown in FIGS. 3 to 6 are basically the same as those of the in-cell type liquid crystal panel shown in FIG. 2, and redundant explanations are omitted.

As described above, the in-cell liquid crystal panel has the touch sensing electrode part inside the liquid crystal cell, not outside the liquid crystal cell. In such a configuration, a conductive layer such as an electrode is not provided on the outer surface of the first transparent substrate of the liquid crystal cell. Here, the conductive layer means a layer having a surface resistance value of 1×10 ¹³ Ω/□ or less. By arranging the optical film with a pressure-sensitive adhesive layer disclosed herein on the viewing side of the first transparent substrate of the liquid crystal cell of the in-cell type liquid crystal panel having such a configuration, the occurrence of static electricity unevenness is highly prevented. be able to.

In addition, the pressure-sensitive adhesive layer-attached optical film disclosed herein can also be preferably used for a semi-in-cell liquid crystal panel. FIG. 7 is a schematic cross-sectional view showing a configuration example of a semi-in-cell liquid crystal panel. In the semi-in-cell liquid crystal panel 600 shown in FIG. 7, a part of the touch sensing electrode portion 630 is arranged inside the liquid crystal cell 620, and another part of the touch sensing electrode portion 630 is arranged outside the liquid crystal cell 620 (specifically, liquid crystal It differs from the in-cell type shown in FIGS. Specifically, the detection electrodes 631 constituting the touch sensing electrode portion 630 are provided on the outer surface of the first transparent substrate 641, and the driving electrodes 632 constituting the touch sensing electrode portion 630 are arranged in the liquid crystal cell 620. It is In this configuration example, the drive electrode 632 is arranged between the liquid crystal layer 625 and the second transparent substrate 642 . This semi-in-cell type liquid crystal panel 600 includes, from the viewing side, an optical film 611, an antistatic layer 613, an adhesive layer 612, a detection electrode 631, a first transparent substrate 641, a liquid crystal layer 625, a drive electrode 632, and a second transparent substrate 642. , has a laminated structure arranged in this order. Further, the optical film 611 has a surface treatment layer 614 on the viewing side. Furthermore, an adhesive layer 652 and an optical film 651 are arranged in this order on the outside of the second transparent substrate 642 . In this liquid crystal panel 600 , the detection electrodes 631 of the touch sensing electrode portion 630 are arranged outside the first transparent substrate 641 and are in contact with the adhesive layer 612 .

In addition, the pressure-sensitive adhesive layer-attached optical film disclosed herein can also be preferably used for an on-cell liquid crystal panel. FIG. 8 is a schematic cross-sectional view showing a configuration example of an on-cell liquid crystal panel. In the on-cell type liquid crystal panel 700 shown in FIG. 8, both the detection electrodes 731 and the drive electrodes 732 related to the touch sensing electrode portion 730 are arranged outside the liquid crystal cell 720 as electrode patterns as shown in FIGS. Different from the in-cell type. In this configuration, a touch sensor function is provided outside the liquid crystal cell 720 (specifically, outside the first transparent substrate 741 and the second transparent substrate 742). More specifically, drive electrodes 732 are arranged on the outer surface of the first transparent substrate 741 of the liquid crystal cell 720 , and detection electrodes 731 are arranged on the drive electrodes 732 . This on-cell liquid crystal panel 700 includes, from the viewing side, an optical film 711, an antistatic layer 713, an adhesive layer 712, a detection electrode 731, a drive electrode 732, a first transparent substrate 741, a liquid crystal layer 725, a drive electrode 734, a second A transparent substrate 742 has a laminated structure arranged in this order. Further, the optical film 711 has a surface treatment layer 714 on the viewing side. Furthermore, an adhesive layer 752 and an optical film 751 are arranged in this order on the outside of the second transparent substrate 742 . In this liquid crystal panel 700 , the detection electrodes 731 of the touch sensing electrode portion 730 are arranged outside the first transparent substrate 741 and are in contact with the adhesive layer 612 . A driving electrode 734 is arranged in the liquid crystal cell 720 . This drive electrode 734 is arranged between the liquid crystal layer 725 and the second transparent substrate 742 .

In the above configuration example, an optical film with an adhesive layer substantially composed of an adhesive layer and an optical film was used as the optical film with the second adhesive layer disposed on the back side. The technique disclosed here is not limited to this, and it is possible to use the optical film with an adhesive layer disclosed here also on the back side of the liquid crystal panel. In that case, the pressure-sensitive adhesive layer-attached optical film disclosed herein may be placed on both sides of the liquid crystal cell. Thereby, the effect of the technology disclosed herein can be exhibited on both sides of the liquid crystal panel. Alternatively, the optical film with a pressure-sensitive adhesive layer disclosed herein may be arranged only on the back side of the liquid crystal panel, not on the viewing side. Even in such a configuration, the effects of the technology disclosed herein can be exhibited.

In addition, in the in-cell liquid crystal panels shown in FIGS. 2, 3, and 6, the detection electrodes were arranged closer to the first transparent substrate (visible side) than the drive electrodes. The configuration of the panel is not limited to this, and the drive electrodes can be arranged closer to the first transparent substrate (visible side) than the detection electrodes.

In the semi-in-cell liquid crystal panel shown in FIG. 7, the detection electrodes are arranged outside the liquid crystal cell (specifically, outside the first transparent substrate), and the drive electrodes are arranged inside the liquid crystal cell (specifically, outside the first transparent substrate). (between the first transparent substrate and the second transparent substrate), but not limited to this, the technology disclosed here is that the sensing electrodes are arranged in the liquid crystal cell and the driving electrodes are arranged in the liquid crystal cell. It can be applied to a semi-in-cell type liquid crystal panel arranged outside the cell.

A liquid crystal display device with a touch sensing function is manufactured using an in-cell liquid crystal panel having the configuration described above. In manufacturing such liquid crystal display devices, various members that can be used in liquid crystal display devices, such as using a backlight or a reflector in the illumination system, can be used in a known or customary manner.

<Constituent material of liquid crystal panel>
A liquid crystal layer containing liquid crystal molecules is used as a liquid crystal layer constituting the liquid crystal cell. A liquid crystal layer according to a preferred embodiment is a liquid crystal layer containing liquid crystal molecules that are homogeneously aligned in the absence of an electric field. As the liquid crystal layer, for example, an IPS liquid crystal layer is preferably used. Other examples of liquid crystal layers that can be used in the technology disclosed herein include TN-type, STN-type, π-type, VA-type, and other liquid crystal layers. The thickness of the liquid crystal layer is, for example, about 1.5 μm to 4 μm.

The detection electrode and the drive electrode (including those integrated with each other) that constitute the touch sensing electrode section are typically transparent conductive layers (transparent electrodes). Materials for these electrodes are not particularly limited, and examples include metals such as gold, silver, copper, platinum, palladium, aluminum, nickel, chromium, titanium, iron, cobalt, tin, magnesium, and tungsten, and alloys of these metals. 1 type, or 2 or more types can be used. In addition, one or more metal oxides of indium, tin, zinc, gallium, antimony, zirconium, and cadmium can be used as the electrode material. Specific examples include metal oxides such as indium oxide, tin oxide, titanium oxide, cadmium oxide, and mixtures thereof. Other metal compounds such as copper iodide may also be used. The metal oxide may further contain oxides of the metal atoms exemplified above, if necessary. For example, indium oxide (ITO) containing tin oxide and tin oxide containing antimony are preferably used, and ITO is particularly preferably used. ITO containing about 80 to 99% by weight of indium oxide and about 1 to 20% by weight of tin oxide is preferably used.

In the in-cell type liquid crystal panel, the detection electrode, the drive electrode, and the electrode integrally formed of both as the touch sensing electrode portion are usually at least one of the first transparent substrate and the second transparent substrate (typically only one) (on the side of the liquid crystal layer in the liquid crystal cell) as a transparent electrode pattern. In the semi-in-cell type liquid crystal panel, one of the detection electrode and the drive electrode is formed inside one of the first transparent substrate and the second transparent substrate (on the side of the liquid crystal layer in the liquid crystal cell), and the detection electrode and the drive electrode are formed. The other of them is formed outside the other of the first transparent substrate and the second transparent substrate. In the on-cell type liquid crystal panel, the detection electrode, the drive electrode, and the electrodes integrally formed of both are formed outside the first transparent substrate and the second transparent substrate (outside the liquid crystal cell). The electrode pattern can be formed by a conventional method.
In addition, the detection electrode, the drive electrode, and the electrode integrally formed of the two in the touch sensing electrode portion may also function as a common electrode for controlling the liquid crystal layer.

The electrode pattern is normally electrically connected to a lead-around line (not shown) formed at the end of the transparent substrate. The lead-out lines are connected to a controller IC (not shown). The shape of the electrode pattern is not limited to the one in which the stripe-shaped wiring lines are orthogonal to each other as in the above configuration example. can take Accordingly, the sense electrodes and the drive electrodes can have cross patterns other than right angles and various other patterns. The electrode pattern may have a height of, for example, approximately 10 nm to 100 nm and a width of approximately 0.1 mm to 5 mm.

Examples of materials for forming the transparent substrate (including the first and second transparent substrates) include glass and polymer films. Therefore, the transparent substrate can be a glass substrate or a polymer substrate. As the glass used for the transparent substrate, various glass materials can be used without particular limitation. Examples of polymer films include polyethylene terephthalate (PET), polycycloolefin, polycarbonate and the like. When the transparent substrate is mainly formed of a glass plate, its thickness is, for example, about 0.1 mm to 1 mm. When the transparent substrate is mainly composed of a polymer film, its thickness is, for example, about 10 μm to 200 μm. The transparent substrate may have an easy-adhesion layer or a hard coat layer on its surface.

In the pressure-sensitive adhesive layer-attached optical film, various conductive materials can be used without particular limitation as the material forming the conductive structure connected to the side surfaces of the pressure-sensitive adhesive layer and the antistatic layer. For example, a conductive paste such as a metal paste containing one or more of silver, gold and other metals is preferably used. Other examples of such materials include conductive adhesives. The conductive structure may have a linear shape extending from the side surface of the antistatic layer or adhesive layer. The material of the conductive structure that can be provided on the side surface of the optical film or the like is the same as described above, and can have the same shape as described above.

In the liquid crystal panel, as the optical film of the optical film with the second pressure-sensitive adhesive layer disposed on the side opposite to the viewing side, the optical film disclosed herein or a known or commonly used optical film can be used depending on the application and purpose. can be used As the second optical film, the same film as the first optical film arranged on the viewing side may be used, or a different film may be used. Similarly, as the second pressure-sensitive adhesive layer constituting the optical film with the second pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer disclosed herein or a known or commonly used pressure-sensitive adhesive layer may be used depending on the application and purpose. can be done. As the second pressure-sensitive adhesive layer, the same layer as the first pressure-sensitive adhesive layer arranged on the viewing side may be used, or a different layer may be used. When the second pressure-sensitive adhesive layer is formed from a known or commonly used pressure-sensitive adhesive, the thickness of the second pressure-sensitive adhesive layer is not particularly limited, and is suitably about 1 to 100 μm, preferably about 2 to 50 μm. , more preferably about 2 to 40 μm, and even more preferably about 5 to 35 μm.

In addition, as the first optical film arranged on the viewing side of the liquid crystal layer and the second optical film arranged on the side opposite to the viewing side, a polarizing film is used or An optical film other than the polarizing film can be used alone or in combination of two or more, or one or more other optical films can be laminated in addition to the polarizing film. The materials that can be used for the optical film disclosed herein and each optical layer that constitutes the optical film are as described above, and detailed description thereof will be omitted.

In addition to the above-described liquid crystal panel and liquid crystal display device including the liquid crystal panel, according to the application and purpose, the arrangement of each component within the range that does not impair the effect of the technology disclosed herein. , the configuration can be changed, and other configurations can be additionally adopted as appropriate. As an example, it is possible to change the design such that a color filter substrate is provided on the liquid crystal cell (for example, the first transparent substrate 141 in FIG. 2).

Several examples related to the present invention are described below, but the present invention is not intended to be limited to those shown in such specific examples. "Parts" and "%" in the following description are by weight unless otherwise specified.

[Production of optical film]
(Preparation Example A1)
A long roll of polyvinyl alcohol (PVA)-based resin film with a thickness of 30 μm (manufactured by Kuraray Co., Ltd., product name “PE3000”) is uniaxially stretched in the longitudinal direction by a roll stretching machine so that it is 5.9 times longer, and is swollen. A polarizer having a thickness of 12 μm was obtained by performing dyeing, cross-linking, washing, and finally drying. Specifically, in the swelling treatment, the film was stretched 2.2 times while being treated with pure water at 20°C. In the dyeing treatment, the film was stretched 1.4 times while being treated at 30° C. in an aqueous solution with an iodine concentration adjusted so that the obtained polarizer had a single transmittance of 45.0%. In the above aqueous solution, the weight ratio of iodine and potassium iodide was 1:7. As the cross-linking treatment, a two-step cross-linking treatment was adopted. In the first-step cross-linking treatment, the film was stretched 1.2 times while being treated in boric acid/potassium iodide aqueous solution at 40°C. This aqueous solution had a boric acid content of 5.0% and a potassium iodide content of 3.0%. In the second-stage cross-linking treatment, the film was stretched 1.6 times while being treated in boric acid/potassium iodide aqueous solution at 65°C. This aqueous solution had a boric acid content of 4.3% and a potassium iodide content of 5.0%. A potassium iodide aqueous solution at 20° C. was used in the cleaning treatment. The potassium iodide content of the aqueous solution for cleaning treatment was set to 2.6%. The drying treatment was performed at 70° C. for 5 minutes.

A 32 μm-thick TAC-HC film having a hard coat (HC) layer on one side of a triacetyl cellulose (TAC) film was attached to one side of the polarizer using a PVA-based adhesive. In addition, a non-stretched cycloolefin polymer (COP) film having a thickness of 13 μm is attached to the other surface of the polarizer using a PVA-based adhesive to have a structure of TAC protective layer/PVA polarizer/COP protective layer. A polarizing film was produced as the optical film A1. A hard coat layer is provided as a surface treatment layer on the TAC protective layer side surface of the optical film A1.

(Preparation Example A2)
This preparation example was performed in the same manner as in Preparation Example A1 except that a 25 μm thick acrylic (CAT) film was attached to the other surface of the polarizer using a PVA adhesive instead of the COP film. Such a polarizing film was produced as an optical film A2. This optical film A2 has a structure of TAC protective layer/PVA polarizer/CAT protective layer, and a hard coat layer is provided as a surface treatment layer on the surface of the optical film A2 on the TAC protective layer side.

[Preparation of composition for forming antistatic layer]
(Preparation Example B1)
6.7 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name "Denatron P-580W"), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name " Epocross WS-300", Mn 40,000, Mw 120,000, polyether unit copolymerization ratio 0 mol%) and 85.3 parts of water are mixed to form an antistatic layer with a solid content concentration of 1.0%. Product B1 was prepared. The resulting composition contained 0.15% thiophene-based polymer and 0.8% oxazoline group-containing polymer. "Denatron P-580W" contains polyurethane as a binder.

(Preparation Example B2)
6.7 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name "Denatron P-618W"), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name " Epocross WS-300", Mn 40,000, Mw 120,000, polyether unit copolymerization ratio 0 mol%) and an aqueous solvent (water 74.1 parts and isopropyl alcohol 8.2 parts) were mixed, and the solid content concentration was A 0.6% antistatic layer-forming composition B2 was prepared. The resulting composition contained 0.45% thiophene-based polymer and 0.1% oxazoline group-containing polymer.

(Preparation Example B3)
6.7 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name "Denatron P-580W"), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name " Epocross WS-300", Mn 40,000, Mw 120,000, copolymerization ratio of polyether units 0 mol%) 8.5 parts, polyethylene glycol (PEG) 200 (average molecular weight: about 200) 0.06 parts, and water 84.7 parts were mixed to prepare an antistatic layer-forming composition B3 having a solid content concentration of 1.0%. The resulting composition contained 0.15% thiophene-based polymer and 0.85% oxazoline group-containing polymer. The PE ratio in the antistatic layer obtained from the PEG content ratio (based on solid content) was 5.6%.

(Preparation Example B4)
6.7 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name "Denatron P-580W"), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name " Epocross WS-300", Mn 40,000, Mw 120,000, copolymerization ratio of polyether unit 0 mol%), 0.21 part of PEG200, and 84.6 parts of water are mixed, and the solid concentration is 1.2%. An antistatic layer-forming composition B4 was prepared. The resulting composition contained 0.15% thiophene-based polymer and 0.8% oxazoline group-containing polymer. The PE ratio in the antistatic layer obtained from the PEG content ratio (solid content basis) was 17.2%.

(Preparation Example B5)
15 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name “Denatron P-521AC”), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name “Epocross WS”) -700", Mn 20,000, Mw 40,000, polyether unit copolymerization ratio 45 mol%) and a mixed solvent (water 19.5 parts and isopropyl alcohol 64.9 parts) were mixed, and the solid content concentration was 1. A 0% antistatic layer-forming composition B5 was prepared. The resulting composition contained 0.55% thiophene-based polymer and 0.4% oxazoline group-containing polymer. Further, the PE ratio in the antistatic layer obtained from the weight ratio of polyether units in the oxazoline group-containing polymer and the content ratio of the oxazoline group-containing polymer (based on solid content) was 4.6%.

(Preparation Example B6)
12.5 parts of a solution containing 1 to 10% of a thiophene-based polymer (manufactured by Nagase ChemteX Corporation, trade name "Denatron P-521AC"), a solution containing an oxazoline group-containing polymer as polymer B (manufactured by Nippon Shokubai Co., Ltd., trade name " Epocross WS-700", Mn 20,000, Mw 40,000, polyether unit copolymerization ratio 45 mol%) and a mixed solvent (19.8 parts of water and 66.5 parts of isopropyl alcohol) were mixed, and the solid content was An antistatic layer-forming composition B6 having a concentration of 1.0% was prepared. The resulting composition contained 0.45% thiophene-based polymer and 0.5% oxazoline group-containing polymer. Further, the PE ratio in the antistatic layer obtained from the weight ratio of polyether units in the oxazoline group-containing polymer and the content ratio of the oxazoline group-containing polymer (based on solid content) was 5.5%.

[Preparation of adhesive composition]
(Preparation Example C1)
75.8 parts of butyl acrylate (BA), 23 parts of phenoxyethyl acrylate (PEA), N-vinyl-2-pyrrolidone (NVP ), 0.3 parts acrylic acid (AA), and 0.4 parts 4-hydroxybutyl acrylate (4HBA). To 100 parts of the above monomer mixture (solid content), 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate, and nitrogen gas was introduced while gently stirring. After purging with nitrogen, the liquid temperature in the flask was maintained at about 55° C., and polymerization reaction was carried out for 8 hours to prepare an acrylic polymer P1 solution having Mw of 1,600,000 and Mw/Mn=3.7.

6 parts of an ionic compound is blended with 100 parts of the solid content of the acrylic polymer P1 solution obtained above, and an isocyanate cross-linking agent (manufactured by Mitsui Chemicals, trade name "Takenate D160N", trimethylolpropane hexamethylene diisocyanate) 0.1 part, 0.3 parts of benzoyl peroxide (manufactured by NOF Corporation, trade name “NIPER BMT”) and γ-glycidoxypropyl methoxysilane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name “KBM-403”) ) to prepare a solution of the acrylic pressure-sensitive adhesive composition C1. As the ionic compound, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)imide (EMI-FSI) was used.

(Preparation Examples C2-C4, C6 and C7)
Acrylic pressure-sensitive adhesive compositions C2 to C4 and C6 were prepared in the same manner as in Preparation Example C1 above, except that the ionic compounds of the types and amounts shown in Table 1 were blended with respect to 100 parts of the solid content of the acrylic polymer P1 solution. and C7 solutions were prepared, respectively. As the ionic compound, methylpropylpyrrolidinium bis(trifluoromethanesulfonyl)imide (MPP-TFSI) was used in acrylic pressure-sensitive adhesive composition C2, and bis(trifluoromethanesulfonyl) was used in acrylic pressure-sensitive adhesive compositions C3, C6 and C7. ) imidelithium (Li-TFSI), and tributylmethylammonium bis(trifluoromethanesulfonyl)imide (TBMA-TFSI) was used in the acrylic adhesive composition C4.

(Preparation Example C5)
An acrylic polymer P2 solution was prepared in the same manner as the acrylic polymer P1 solution except that the composition of the monomer mixture was 76.9 parts of BA, 18 parts of benzyl acrylate, 5 parts of AA and 0.1 part of 4HBA.
A solution of acrylic pressure-sensitive adhesive composition C5 was prepared in the same manner as in Preparation Example C1 above, except that 8 parts of Li-TFSI was blended as an ionic compound with respect to 100 parts of the solid content of the acrylic polymer P2 solution obtained above. prepared.

<Examples 1 to 7 and Comparative Examples 1 to 4>
A coating liquid composed of any one of the antistatic layer-forming compositions B1 to B6 was applied to one side (the side not provided with the hard coat layer) of the optical film A1 or A2 so that the thickness after drying was 40 nm. It was applied and dried at 80° C. for 2 minutes to form an antistatic layer.
A solution of any of the above acrylic adhesive compositions C1 to C7 is applied to one side of a polyethylene terephthalate (PET) film (release liner, manufactured by Mitsubishi Chemical Polyester Film Co., Ltd., product number "MRF38") treated with a silicone release agent. , and dried at 155°C for 1 minute to form a pressure-sensitive adhesive layer on the surface of the release liner. Then, the pressure-sensitive adhesive layer formed on the release liner was transferred to the antistatic layer-side surface of the optical film with an antistatic layer. Thus, an optical film with an adhesive layer according to each example was produced. These adhesive layer-attached optical films have a structure of optical film/antistatic layer/adhesive layer, a hard coat layer is provided on the rear surface of the optical film side, and the adhesive surface of the adhesive layer is a release liner. protected. Table 1 shows the combinations of the optical film, antistatic layer-forming composition and acrylic pressure-sensitive adhesive composition used in each example.

[Anchor force]
The release liner is removed from the optical film with an adhesive layer according to each example, an ITO film (manufactured by Oike Kogyo Co., Ltd., trade name “125 Tetrait OES”) is attached to the exposed adhesive surface, and the measurement is performed by cutting it into a width of 25 mm. samples were obtained. A sample for measurement was set in a tensile tester, the optical film with an adhesive layer was peeled off from the ITO film at a speed of 300 mm/min in the direction of 180 degrees, and the peeling force [N/25 mm] at that time was recorded as the anchoring force. .

[ESD (electrostatic discharge) test]
An in-cell liquid crystal cell was prepared, the release liner was peeled off from the optical film with the pressure-sensitive adhesive layer according to each example, and the exposed adhesive surface was attached to the viewing side of the in-cell liquid crystal cell as shown in FIG. . Next, a silver paste with a width of 5 mm was applied to the side surface of the optical film with an adhesive layer attached to the in-cell type liquid crystal cell so as to cover all sides of the hard coat layer, optical film, antistatic layer, and adhesive layer. Then, a liquid crystal display panel was obtained by connecting to a ground electrode from the outside. The liquid crystal display panel was set on the backlight device under conditions of 23° C. and 55% RH, and an Electro-static Discharge Gun was fired at an applied voltage of 10 kV to the optical film surface on the viewing side. The time until the white spots disappeared due to electricity was measured (initial evaluation). In addition, a similar ESD test was performed after immersing in a humidified environment of 60° C. and 95% RH for 250 hours and drying at 40° C. for 1 hour (evaluation after humidification). The obtained measurement results were evaluated according to the following criteria.
(Evaluation criteria)
○: White unevenness disappears in less than 1 second both initially and after humidification △: White unevenness disappears in less than 3 seconds both in the initial stage and after humidification ×: White unevenness disappears time varies, 3 either initially or after humidification took more than a second.

[Touch sensor sensitivity]
An in-cell liquid crystal cell was prepared, the release liner was peeled off from the optical film with the pressure-sensitive adhesive layer according to each example, and the exposed adhesive surface was attached to the viewing side of the in-cell liquid crystal cell as shown in FIG. . A liquid crystal display device with a built-in touch sensing function was manufactured by connecting a lead-out wiring (not shown) around the transparent electrode pattern inside the in-cell type liquid crystal cell to a controller IC (not shown). Visual observation was performed while the input display device of the liquid crystal display device with a built-in touch sensing function was being used, and the presence or absence of malfunction was confirmed.
(Evaluation criteria)
〇: No malfunction ×: Malfunction

[Heat durability test]
The optical film with an adhesive layer according to each example was cut into 15-inch size, the release liner was removed, and then the exposed adhesive surface was coated with non-alkali glass (manufactured by Corning Inc., product number "EG-XG") with a thickness of 0.7 mm. ”) using a laminator to obtain a sample for measurement. The resulting measurement sample was autoclaved at 50° C. and 0.5 MPa for 15 minutes to adhere the pressure-sensitive adhesive layer to the non-alkali glass. After autoclave-treated measurement samples were treated in an atmosphere of 85° C. for 500 hours, the appearance between the optical film with the pressure-sensitive adhesive layer and the alkali-free glass was visually evaluated according to the following criteria.
(Evaluation criteria)
◯: No change in appearance such as foaming or peeling was observed.
Δ: Slight bubbling and peeling were observed at the edges, but at a practically acceptable level.
x: Significant peeling was observed at the edge.

[Humidification cloudiness evaluation test]
An optical film with an adhesive layer according to each example was cut into a size of 50 mm×50 mm and attached to glass. Furthermore, a PET film having a thickness of 25 μm (manufactured by Mitsubishi Plastics Co., Ltd., product number “Diafoil T100-25B”) was cut into a size of 50 mm×50 mm and adhered to the upper surface of the optical film to obtain a sample for measurement. After the sample for measurement was placed in an environment of 60° C. and 95% RH for 250 hours, it was taken out to room temperature and the haze value was measured 10 minutes later and evaluated according to the following criteria. The haze value was measured using a haze meter HM150 manufactured by Murakami Color Research Laboratory.
(Evaluation criteria)
○: Haze value of 5 or less △: Haze value of more than 5 and less than 10, practically no problem level ×: Haze value of 10 or more, practically problematic

Schematic structure of optical film with adhesive layer according to each example, surface resistance value of each layer [Ω/□], anchoring force [N/25 mm], ESD test, touch sensor sensitivity, heat durability test, humidified white turbidity evaluation test Table 1 shows the results.
In addition, as the polymer B contained in the antistatic layer, the optical film with an adhesive for each of the structure using a polyether unit of more than 10 mol% and the structure using a polyether unit of 10 mol% or less was cut obliquely in the thickness direction, and the results of TOF-SIMS analysis of the cut surface are shown in FIGS.

As shown in Table 1, both the antistatic layer and the adhesive layer contain a conductive component, and the content of the ionic compound in the adhesive layer is 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer. In Examples 1 to 7, the surface resistance value of the pressure-sensitive adhesive layer was 1×10 ¹⁰ Ω/□ or less, and the content of the ionic compound was less than 5 parts by weight. results were excellent. Moreover, in Examples 1 to 7, the pressure-sensitive adhesive layer had a surface resistance value of 1×10 ⁸ Ω/□ or more, and had good touch sensor sensitivity. It is considered that the optical films with pressure-sensitive adhesive layers of Examples 1 to 7 exhibit stable characteristics regardless of the contact with the conducting path provided on the side surface of the film.

Further, Examples 1 to 7 in which the polyether unit in the molecule of the functional group-containing polymer B (specifically, the oxazoline group-containing polymer) contained in the antistatic layer is 10 mol% or less, the polyether unit in the polymer B molecule showed a higher anchoring force than Comparative Examples 1 to 3 in which the content exceeds 10 mol %. Regarding this point, from the TOF-SIMS analysis results shown in FIGS. While the ionic compound in the adhesive layer was unevenly distributed on the antistatic layer side, in the configuration using polyether units of 10 mol% or less (Fig. 10), the ionic compound in the adhesive layer It was confirmed that they were uniformly dispersed in the thickness direction. The above results support that the chemical structure of polymer B in the antistatic layer changes the behavior of the ionic compound in the pressure-sensitive adhesive layer, and that the change correlates with the change in anchoring force.

Further, the optical films with pressure-sensitive adhesive layers according to Examples 1 to 7 exhibited practically acceptable levels of performance in the heat durability test and humidified cloudiness evaluation test. In these examples, it was found that limiting the amount of the ionic compound tends to improve the heat durability. In addition, the examples using an organic cation-anion salt as the ionic compound tended to be less likely to become cloudy when humidified, and were excellent in humidification resistance reliability.

From the above results, an optical film with an adhesive layer comprising an optical film, an antistatic layer, and an adhesive layer disposed on the antistatic layer, the content of the ionic compound in the adhesive layer is 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer, and the polyether unit in the molecule of the functional group b-containing polymer B contained in the antistatic layer is 10 mol% or less. It can be seen that an optical film with a pressure-sensitive adhesive layer is realized which has the above and is excellent in the anchoring property of the pressure-sensitive adhesive layer. In addition, it can be seen that the above conductivity can achieve both good touch sensor sensitivity and prevention of static electricity unevenness in applications for touch sensor-equipped liquid crystal panels.

10, 110, 210, 310, 410, 510, 610, 710: (First) Optical film with adhesive layer 11, 111, 211, 311, 411, 511, 611, 711: (First) Optical film 11A: Optical film first surface 11B: Optical film second surface 12, 112, 212, 312, 412, 512, 612, 712: (first) adhesive layer 13, 113, 213, 313, 413, 513, 613, 713: Antistatic layer 14, 114, 214, 314, 414, 514, 614, 714: Surface treatment layer 100, 200, 300, 400, 500: In-cell liquid crystal panel 600: Semi-in-cell liquid crystal panel 700: On-cell liquid crystal panel 120, 220, 320, 420, 520, 620, 720: Liquid crystal cell 125, 225, 325, 425, 525, 625, 725: Liquid crystal layer 130, 230, 330, 430, 530, 630, 730: Touch sensing electrode part 131, 231, 331, 431, 531, 631, 731: detection electrodes 132, 232, 332, 432, 532, 632, 732: drive electrodes 141, 241, 341, 441, 541, 641, 741: first transparent substrate 142, 242, 342, 442, 542, 642, 742: Second transparent substrate 150, 250, 350, 450, 550, 650, 750: Optical film with second adhesive layer 151, 251, 351, 451, 551, 651, 751: Second optical films 152, 252, 352, 452, 552, 652, 752: Second adhesive layers 170, 270, 370, 470, 570, 670, 770: Conductive structures 171, 271, 371, 471 , 571, 671, 771: conductive structures

Claims (9)

An optical film with an adhesive layer for use in an in-cell liquid crystal cell,
The in-cell liquid crystal cell:
a liquid crystal layer comprising liquid crystal molecules;
a first transparent substrate and a second transparent substrate sandwiching the liquid crystal layer, wherein the first transparent substrate is positioned on the viewing side;
a touch sensing electrode portion disposed between the first transparent substrate and the second transparent substrate;
and
The optical film with the pressure-sensitive adhesive layer:
an optical film;
an antistatic layer provided on at least one surface of the optical film;
a pressure-sensitive adhesive layer disposed on the antistatic layer and in contact with the antistatic layer ;
and
The antistatic layer and the pressure-sensitive adhesive layer each have a surface resistance value within the range of 1×10 ⁸ to 1×10 ¹⁰ Ω/□,
The pressure-sensitive adhesive layer contains a polymer A as a base polymer and an ionic compound,
The content of the ionic compound in the adhesive layer is 5 to 20 parts by weight with respect to 100 parts by weight of the base polymer,
The antistatic layer comprises a conductive polymer and a polymer B,
The polymer A has a functional group a, and the polymer B has a functional group b that interacts with the functional group a, where the interactions are covalent bonds, dipole-dipole based on molecular interactions, hydrogen bonding, or van der Waals forces,
The optical film with a pressure-sensitive adhesive layer, wherein the polymer B contains 10 mol % or less of polyether units in its molecule. One of the functional group a and the functional group b is at least one selected from the group consisting of a carboxy group, an acid anhydride group, a hydroxyl group and a thiol group, and the other is the group consisting of an oxazoline group and an isocyanate group. The optical film with an adhesive layer according to claim 1, which is at least one selected from. 3. The pressure-sensitive adhesive layer-carrying optical film according to claim 1, wherein the ionic compound is selected from alkali metal salts and organic cation-anion salts. The optical film with an adhesive layer according to any one of claims 1 to 3, wherein the ionic compound is an ionic liquid having a melting point of 40°C or less. The optical film with a pressure-sensitive adhesive layer according to any one of claims 1 to 4, wherein the conductive polymer is a thiophene-based polymer. The optical film with a pressure-sensitive adhesive layer according to any one of claims 1 to 5, wherein the polymer A is an acrylic polymer. The optical film with an adhesive layer according to any one of claims 1 to 6, wherein the polymer B is an oxazoline group-containing polymer. A liquid crystal cell and the optical film with an adhesive layer according to any one of claims 1 to 7,
Said liquid crystal cell:
a liquid crystal layer comprising liquid crystal molecules;
a first transparent substrate and a second transparent substrate sandwiching the liquid crystal layer, wherein the first transparent substrate is positioned on the viewing side;
a touch sensing electrode portion disposed between the first transparent substrate and the second transparent substrate;
An in-cell liquid crystal cell comprising
The in-cell type liquid crystal panel, wherein the adhesive layer of the optical film with an adhesive layer is attached to the surface of the first transparent substrate. A liquid crystal display device comprising the in-cell liquid crystal panel according to claim 8 .

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