JP6730348B2 - One-sided protective polarizing film with adhesive layer, image display device and continuous production method thereof - Google Patents

Description

The present invention relates to a one-sided protective polarizing film having a protective film provided on only one side of a polarizer and a one-sided protective polarizing film with an adhesive layer having an adhesive layer. The pressure-sensitive adhesive layer-attached piece protective polarizing film can be used alone or as an optical film obtained by laminating the same to form an image display device such as a liquid crystal display device (LCD) or an organic EL display device.

In the liquid crystal display device, it is indispensable to dispose the polarizing film on both sides of the glass substrate forming the surface of the liquid crystal panel due to its image forming method. As the polarizing film, generally, a polyvinyl alcohol-based film and a polarizer made of a dichroic material such as iodine having a protective film bonded to one or both surfaces thereof with a polyvinyl alcohol-based adhesive or the like are used. ..

An adhesive is usually used when the polarizing film is attached to a liquid crystal cell or the like. In addition, the pressure-sensitive adhesive is preliminarily provided as a pressure-sensitive adhesive layer on one surface of the polarizing film, since it has advantages such as being able to instantly fix the polarizing film and not requiring a drying step to fix the polarizing film. .. That is, a piece protective polarizing film with an adhesive layer is generally used for sticking the polarizing film.

In addition, the polarizing film and the adhesive layer-attached piece protective polarizing film have a polarizer under a severe environment of thermal shock (for example, a heat shock test in which temperature conditions of -30°C and 80°C are repeated or a high temperature test of 100°C). There is a problem that cracks (penetration cracks) are likely to occur in the entire absorption axis direction of the polarizer due to the change in the shrinkage stress. That is, the pressure-sensitive adhesive layer-attached piece protective polarizing film was not sufficiently durable due to thermal shock in the severe environment. In particular, from the viewpoint of thinning, the pressure-sensitive adhesive layer-provided one-sided protective polarizing film using the one-sided protective polarizing film in which the protective film is provided only on one surface of the polarizer has insufficient durability due to the thermal shock. Moreover, the through cracks caused by the thermal shock were likely to occur when the size of the polarizing film was increased.

For example, in order to impart high durability in a high temperature environment, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached piece protective polarizing film has a storage elastic modulus at 23° C. of 0.2 to 10 MPa and a thickness of 2 μm or more and 25 μm. It has been proposed to use less than one (Patent Document 1). Further, in order to impart good durability even in a high temperature environment, a pressure-sensitive adhesive layer is provided on one surface of the polarizer, and a protective layer made of a transparent resin film is provided on the other surface of the polarizer. In the plate, it has been proposed to use, as the pressure-sensitive adhesive layer, one having a storage elastic modulus of 0.15 to 1 MPa in the temperature range of 23 to 80°C (Patent Document 2). Further, in order to suppress the occurrence of the through cracks, as the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached protective polarizing film, the shrinkage force in the direction orthogonal to the absorption axis of the polarizer is controlled to be small, and the pressure-sensitive adhesive layer is It has been proposed to use one having a storage elastic modulus of 0.20 MPa or more at 23° C. (Patent Document 3). Further, thinning has also been carried out on a polarizer, and for example, a thin polarizer having high orientation has been proposed in which optical characteristics such as single transmittance and polarization degree are controlled (Patent Document 4).

However, in Patent Document 1, although the durability is satisfied, the thickness of the polarizer is as large as 25 μm, so that it is not possible to prevent the occurrence of a through crack due to the contracting stress of the polarizer. Further, in Patent Documents 1 to 3, since it is an object to improve the durability of the pressure-sensitive adhesive layer-attached piece protective polarizing film, a relatively large amount of boric acid is used for the polarizer. When the amount of boric acid contained in the polarizer is more than a specific value, crosslinking due to boric acid is promoted during heating, and the shrinkage stress of the polarizer increases, which is not preferable from the viewpoint of suppressing the occurrence of through cracks. I also understood that. That is, in Patent Documents 1 to 3, although the through cracks can be prevented to some extent by controlling the storage elastic modulus of the pressure-sensitive adhesive layer, it cannot be said that the occurrence of the through cracks can be sufficiently suppressed.

On the other hand, thinning has also been performed on polarizers. When the thickness of the polarizer used for the pressure-sensitive adhesive layer-attached polarizing plate film is reduced, the change in shrinkage stress of the polarizer becomes small. Therefore, it has been found that the thinned polarizer can suppress the occurrence of the through crack.

However, in the pressure-sensitive adhesive layer-attached protective polarizing film in which the occurrence of the through cracks is suppressed, the optical characteristics are controlled as in Patent Document 4 and the polarizer is thin (for example, when the thickness is 12 μm or less). When a mechanical shock is applied to the pressure-sensitive adhesive layer-attached protective polarizing film (including a case where a load is applied to the polarizer side due to convex bending), an extremely fine slit (partially slit) in the absorption axis direction of the polarizer ( Hereinafter, it is also known that nano slits are generated. It was also found that the nanoslit occurs regardless of the size of the polarizing film. Furthermore, it was also found that the nanoslit does not occur when using both protective polarizing films having protective films on both sides of the polarizer. Further, when a through-crack occurs in the polarizer, the stress around the through-crack is released, so the through-crack does not occur adjacently, but in addition to the nanoslits occurring independently, adjacently. It turned out to occur. Further, it was also found that the through crack has a progressive property extending in the absorption axis direction of the polarizer in which the crack is generated, but the nanoslit does not have the progressive property. Thus, the nanoslit, in the one-sided protective polarizing film in which the occurrence of through cracks is suppressed, is a new problem that occurs when the polarizer is thin, and the optical characteristics are controlled within a predetermined range. It was found that this is a problem caused by a phenomenon different from the above-described through crack.

Further, since the nano slits are extremely thin, they cannot be detected under normal environment. Therefore, even if nanoslits are generated in the polarizer, it is difficult to confirm a defect due to light leakage of the pressure-sensitive adhesive layer-attached piece protective polarizing film at first glance. That is, usually, the one-sided protective polarizing film is produced in the form of a long film and is subjected to a defect inspection by an automatic optical inspection, but it is difficult to detect the nanoslit as a defect by this defect inspection. The defects due to the nano slits can be detected by spreading the nano slits in the width direction when the adhesive layer-attached piece protective polarizing film is bonded to the glass substrate of the image display panel and placed in a heating environment. It was also found that (for example, the presence or absence of light leakage).

Therefore, in the pressure-sensitive adhesive layer-attached piece protective polarizing film using a thin polarizer, it is desired to suppress not only through cracks but also defects due to nanoslits. Furthermore, since the pressure-sensitive adhesive layer-attached one-piece protective polarizing film is thinner than a polarizing film having both protective structures having protective films on both sides, the polarizing film is likely to be broken or broken during handling.

In order to suppress the defects due to the nanoslits, a technique has been proposed in which a transparent layer (coating layer) is provided between the polarizer and the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached protective polarizing film (Patent Document 5). Providing the transparent layer makes it difficult for the polarizing film to bend when external stress is applied to the polarizing film, so that the generation of nanoslits can be suppressed.

JP, 2010-44211, A JP, 2008-197309, A JP, 2013-72951, A Patent No. 4751481 Patent No. 6077618

In addition, when a sticking protective polarizing film with a pressure-sensitive adhesive layer is stuck to a glass substrate that forms the surface of a liquid crystal panel or an ITO film provided on the glass substrate, foreign matter or air bubbles are mixed in and a bonding error occurs. Therefore, it is necessary to separate the polarizing film from the glass substrate or the ITO film. The pressure-sensitive adhesive layer-attached protective polarizing film using a thin polarizer has a very thin overall thickness because the polarizer is thin and the protective film is provided only on one side of the polarizer. Therefore, the pressure-sensitive adhesive layer-attached piece protective polarizing film using the conventional thin polarizer has a problem that it is easily broken when peeled from the glass substrate or the ITO film.

The present invention is capable of suppressing defects due to nanoslits without providing a coating layer between the polarizer and the pressure-sensitive adhesive layer, and further to provide a pressure-sensitive adhesive layer-attached protective film having excellent reworkability. To aim.

Another object of the present invention is to provide an image display device having the pressure-sensitive adhesive layer-attached piece protective polarizing film, and a continuous manufacturing method thereof.

As a result of earnest studies, the inventors of the present invention have found that the above-mentioned problems can be solved by the following adhesive layer-attached piece protective polarizing film and the like, and have completed the present invention.

That is, the present invention is a one-sided protective polarizing film having a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer directly on the polarizer side of the one-sided protective polarizing film or a coating layer having a protective film only on one side of the polarizer. And
The pressure-sensitive adhesive layer has a storage elastic modulus at −40° C. of 7.0×10 ⁷ Pa or more,
Peeling speed of the pressure-sensitive adhesive layer to the alkali-free glass surface, the peeling speed at a peeling speed of 300 mm/min and a peeling angle of 90 degrees is 8 N/25 mm or less, and the peeling speed of the pressure-sensitive adhesive layer to the ITO film surface of the ITO-coated glass. An adhesive layer-attached piece protective polarizing film having an adhesive force of 300 N/min and a peeling angle of 90 degrees of 8 N/25 mm or less.

The present inventors have conducted extensive studies on the relationship between the physical properties of the pressure-sensitive adhesive layer provided on the polarizer side of the one-sided protective polarizing film and the number of occurrence of nanoslits, and the storage elastic modulus and the nanometer in the low-temperature region of the pressure-sensitive adhesive layer. It was found that there is a correlation with the number of slits generated. In detail, generally, the storage elastic modulus of the pressure-sensitive adhesive layer when the external stress is applied to the pressure-sensitive adhesive layer at high speed is higher than that when the external stress is applied at low speed. Further, the storage elastic modulus of the pressure-sensitive adhesive layer in the low temperature region is higher than that in the high temperature region. That is, the storage elastic modulus of the pressure-sensitive adhesive layer when external stress is applied to the pressure-sensitive adhesive layer at a high speed exhibits the same physical property tendency (the storage elastic modulus tends to increase) as the storage elastic modulus of the pressure-sensitive adhesive layer in the low temperature region. .. On the other hand, when manufacturing a liquid crystal panel or using a liquid crystal display device, most of external stress is considered to be applied to the adhesive protective film with adhesive layer at a high speed. It is considered that this is more likely to occur when it is added at a high speed than when it is added to the piece-protective polarizing film with an agent layer. Therefore, it is possible to study the relationship between the storage modulus of the adhesive layer and the number of nanoslits generated when external stress is applied to the adhesive layer at high speed. It is difficult to measure the storage elastic modulus of the pressure-sensitive adhesive layer when exposed. Therefore, the storage elastic modulus in the low temperature region of the pressure-sensitive adhesive layer showing the same physical property tendency as the storage elastic modulus of the pressure-sensitive adhesive layer when an external stress is applied to the pressure-sensitive adhesive layer at high speed and the pressure-sensitive adhesive layer with high external stress. When we examined the relationship with the number of nanoslits generated when applied to a polarizing film, we found that the storage modulus of the adhesive layer in the low temperature region, especially at -40°C, and the external stress at a high speed, the adhesive layer-attached protective film. It was found that there is a clear correlation with the number of nanoslits generated when added to the polarizing film. Then, by providing the pressure-sensitive adhesive layer having a storage elastic modulus at −40° C. of 7.0×10 ⁷ Pa or more on the polarizer side of the one-sided protective polarizing film, it is possible to effectively generate nanoslits without providing a coating layer. It was found that it can be suppressed. Further, when a coating layer is provided between the polarizer and the pressure-sensitive adhesive layer, the synergistic effect of the pressure-sensitive adhesive layer and the coating layer can more effectively suppress the generation of nanoslits.

Further, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention is adjusted to have the above-mentioned adhesive force, and thus even when a thin polarizer is used, the polarizing film is a glass substrate, or a glass. It can be peeled from the ITO film provided on the substrate without breaking.

In the pressure-sensitive adhesive protective film with a pressure-sensitive adhesive layer, the pressure-sensitive adhesive layer preferably has a loss elastic modulus peak of −45° C. or higher.

In the pressure-sensitive adhesive layer-attached protective polarizing film, the pressure-sensitive adhesive layer preferably has a storage elastic modulus at 85° C. of 5.5×10 ⁴ Pa or more and 1.4×10 ⁵ Pa or less.

In the pressure-sensitive adhesive layer-attached protective polarizing film, the pressure-sensitive adhesive layer contains a (meth)acrylic polymer as a base polymer, and the (meth)acrylic polymer serves as a monomer unit.
80% by weight or more of an alkyl (meth)acrylate (A) having a homopolymer glass transition temperature of less than 0° C., and an alkyl (meth)acrylate (b1) and homopolymer having a homopolymer glass transition temperature of 0° C. or more Having a glass transition temperature of 0° C. or higher and at least one high Tg monomer (B) selected from the group consisting of (meth)acryloyl group-containing monomers (b2) having a heterocycle in an amount of 0.1 to 20 wt. % Is preferably contained.

Further, the (meth)acrylic polymer is at least one selected from the group consisting of a nitrogen-containing monomer, a carboxyl group-containing monomer, and a hydroxyl group-containing monomer as a monomer unit, and the (meth)acryloyl group It is preferable to contain a polar monomer other than the contained monomer (b2).

The nitrogen-containing monomer is preferably a vinyl-based monomer having a lactam ring. The vinyl-based monomer having the lactam ring is preferably a vinylpyrrolidone-based monomer. The vinylpyrrolidone-based monomer is preferably N-vinylpyrrolidone.

The (meth)acrylic polymer preferably contains, as a monomer unit, the nitrogen-containing monomer in an amount of 0.1 to 5% by weight, and the carboxyl group-containing monomer in an amount of 0.01 to 2% by weight. It is preferable to contain the hydroxyl group-containing monomer in an amount of 0.01 to 1% by weight.

The pressure-sensitive adhesive layer preferably contains a rework improving agent.

The content of the rework improving agent in the pressure-sensitive adhesive layer is preferably 0.001 to 10 parts by weight with respect to 100 parts by weight of the base polymer which is a material for forming the pressure-sensitive adhesive layer.

In the pressure-sensitive adhesive layer-attached protective polarizing film, the polarizer preferably has a thickness of 12 μm or less.

Further, in the pressure-sensitive adhesive layer-attached piece protective polarizing film, the polarizer contains a polyvinyl alcohol-based resin, and the optical characteristics represented by a single transmittance T and a polarization degree P are represented by the following formula P>-( 10 ^{0.929 T-42.4} −1)×100 (where T<42.3), or
It is preferably configured so as to satisfy the condition of P≧99.9 (where T≧42.3).

In the pressure-sensitive adhesive layer-attached protective polarizing film, it is preferable that the polarizer contains 25% by weight or less of boric acid based on the total amount of the polarizer.

Moreover, a separator can be provided in the pressure-sensitive adhesive layer of the piece protective polarizing film with a pressure-sensitive adhesive layer. The pressure-sensitive adhesive layer-attached protective polarizing film provided with a separator can be used as a wound body.

The present invention also relates to an image display device having the pressure-sensitive adhesive layer-attached piece protective polarizing film.

Further, the present invention is unrolled from the wound body of the pressure-sensitive adhesive layer-attached piece protective polarizing film, the pressure-sensitive adhesive layer-attached piece protective polarizing film conveyed by the separator, through the pressure-sensitive adhesive layer of the image display panel. The present invention relates to a continuous manufacturing method of an image display device including a step of continuously bonding to a surface.

In the pressure-sensitive adhesive layer-attached one-sided protective polarizing film of the present invention, the pressure-sensitive adhesive layer having a storage elastic modulus at −40° C. of 7.0×10 ⁷ Pa or more is provided on the polarizer side of the one-sided protective polarizing film. Since the pressure-sensitive adhesive layer has high elasticity characteristics when the external stress is applied at high speed (the storage elastic modulus in the low temperature region is high), the polarizing film becomes difficult to bend when the mechanical impact is applied to the polarizing film at high speed. .. As a result, it is possible to effectively suppress the generation of nanoslits without providing a coating layer. In addition, the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention can omit the step of providing the coating layer, and thus can improve the productivity as compared with the conventional one having the coating layer. Further, the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention is adjusted to have an adhesive force of 8 N/25 mm or less with respect to the non-alkali glass surface and the ITO film surface of the glass with an ITO film, and thus the thin polarizer. Even in the case of using, the polarizing film can be peeled off from the glass substrate or the ITO film provided on the glass substrate without breaking.

1 is an example of a schematic cross-sectional view of a pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention. It is an example of the conceptual diagram which compares the nano slit which arises in a polarizer, and a penetration crack. It is a schematic diagram explaining an evaluation item concerning a nano slit of an example and a comparative example. It is an example of the photograph which shows the crack which arises by the nano slit which concerns on evaluation of an Example and a comparative example. It is an example of a schematic sectional view of a continuous manufacturing system of an image display device.

The pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention will be described below with reference to FIG. The pressure-sensitive adhesive layer-provided piece protective polarizing film 11 of the present invention has, for example, the piece protective polarizing film 10 and the pressure-sensitive adhesive layer 4. As shown in FIG. 1, the one-sided protective polarizing film 10 has the protective film 2 on only one surface of the polarizer 1. The polarizer 1 and the protective film 2 are laminated via an adhesive layer 3 (in addition, an intervening layer such as a pressure-sensitive adhesive layer and an undercoat layer (primer layer)). Although not shown, the one-sided protective polarizing film 10 can be laminated with the easy-adhesion layer and the adhesive layer by providing the protection film 2 with an easy-adhesion layer or by subjecting it to an activation treatment. Although not shown, a plurality of protective films 2 can be provided. The plurality of protective films 2 can be laminated with an adhesive layer 3 (other than that, an intervening layer such as a pressure-sensitive adhesive layer and an undercoat layer (primer layer)).

Further, as shown in FIG. 1, the pressure-sensitive adhesive layer 4 in the pressure-sensitive adhesive layer-attached piece protective polarizing film 11 of the present invention is provided on the polarizer 1 side of the piece protective polarizing film 10. Although not shown, a coating layer may be provided between the polarizer 1 and the pressure-sensitive adhesive layer 4. The coating layer is not particularly limited, and for example, a known transparent layer described in Japanese Patent No. 6077618 or the like can be applied. A separator 5 can be provided on the pressure-sensitive adhesive layer 4 of the pressure-sensitive adhesive layer-attached protective polarizing film 11 of the present invention, and a surface protection film 6 can be provided on the opposite side. In the pressure-sensitive adhesive layer-attached piece protective polarizing film 11 of FIG. 1, a case where both the separator 5 and the surface protective film 6 are provided is shown. The pressure-sensitive adhesive layer-attached protective polarizing film 11 having at least the separator 5 (further, having the surface protective film 6) can be used as a wound body, and as will be described later, for example, is fed from the wound body, A method of sticking the pressure-sensitive adhesive layer-attached piece protective polarizing film 11 conveyed by the separator 5 onto the surface of the image display panel via the pressure-sensitive adhesive layer 4 (hereinafter, also referred to as "roll-to-panel method". Is advantageous for application to Japanese Patent No. 446043). The pressure-sensitive adhesive layer-attached protective polarizing film shown in FIG. 1 is preferably used from the viewpoint of suppressing warpage of a display panel after bonding, suppressing generation of nanoslits, and the like.

FIG. 2 is a conceptual diagram comparing the nanoslit a generated in the polarizer with the through crack b. 2A shows the nanoslit a generated in the polarizer 1, and FIG. 2B shows the through crack b generated in the polarizer 1. The nanoslit a is generated by mechanical impact and is partially generated in the absorption axis direction of the polarizer 1. The nanoslit a cannot be confirmed at the beginning, but in a thermal environment (for example, 80° C. or 60° C., 90% RH), it can be confirmed by the spread in the width direction. On the other hand, it is considered that the nanoslit a does not have the progressive property extending in the absorption axis direction of the polarizer. Further, it is considered that the nano slits a occur regardless of the size of the polarizing film. The nanoslits a may be generated independently, or may be generated adjacently. On the other hand, the through crack b is generated by thermal shock (for example, heat shock test). The through crack has a property of extending in the absorption axis direction of the polarizer in which the crack has occurred. When the through crack b occurs, the stress in the periphery is released, and therefore the through crack does not occur adjacently.

<Polarizer>
In the present invention, the thickness of the polarizer is preferably 12 μm or less, more preferably 10 μm or less, further preferably 8 μm or less, still more preferably 7 μm or less, particularly preferably from the viewpoint of reducing the thickness and suppressing the occurrence of through cracks. Is 6 μm or less. On the other hand, the thickness of the polarizer is preferably 1 μm or more. Such a thin polarizer has little thickness unevenness and excellent visibility, and since it has little dimensional change, it has excellent durability against thermal shock.

A polarizer using a polyvinyl alcohol resin is used as the polarizer. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene/vinyl acetate copolymer partially saponified films, and dichroic dyes such as iodine and dichroic dyes. Examples thereof include polyene-based oriented films such as substances adsorbed and uniaxially stretched, polyvinyl alcohol dehydration products, polyvinyl chloride dehydrochlorination products, and the like. Among these, a polarizer made of a polyvinyl alcohol film and a dichroic substance such as iodine is preferable.

A polarizer obtained by dyeing a polyvinyl alcohol-based film with iodine and uniaxially stretching can be produced, for example, by dyeing polyvinyl alcohol by immersing it in an aqueous solution of iodine and stretching it to 3 to 7 times its original length. If necessary, boric acid, zinc sulfate, zinc chloride, etc. may be contained, or the solution may be immersed in an aqueous solution of potassium iodide or the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed with water before dyeing. By washing the polyvinyl alcohol-based film with water, it is possible to wash the stains and anti-blocking agent on the surface of the polyvinyl alcohol-based film, and by swelling the polyvinyl alcohol-based film, the effect of preventing unevenness such as uneven dyeing is also obtained. is there. Stretching may be performed after dyeing with iodine, stretching while dyeing, or stretching and then dyeing with iodine. Stretching can be performed in an aqueous solution of boric acid or potassium iodide or in a water bath.

The polarizer preferably contains boric acid from the viewpoint of stretching stability and optical durability. Further, the content of boric acid contained in the polarizer is preferably 25% by weight or less, and more preferably 20% by weight or less with respect to the total amount of the polarizer from the viewpoint of suppressing the occurrence of through cracks and nanoslits and suppressing expansion. It is preferable that the content is 18% by weight or less, further preferably 16% by weight or less. When the content of boric acid contained in the polarizer exceeds 25% by weight, the contraction stress of the polarizer is increased even when the thickness of the polarizer is reduced (for example, the thickness is 12 μm or less), and penetration cracks are likely to occur. Is not preferable. On the other hand, from the viewpoint of stretching stability and optical durability of the polarizer, the boric acid content is preferably 10% by weight or more, and more preferably 12% by weight or more, based on the total amount of the polarizer.

As a thin polarizer, typically,
Patent No. 4751486 specification,
Patent No. 4751481,
Japanese Patent No. 4815544,
Japanese Patent No. 5048120,
Japanese Patent No. 5587517,
International Publication 2014/0775599 pamphlet,
International Publication 2014/077636 pamphlet,
And the thin polarizers obtained from the production methods described therein.

The polarizer has optical characteristics represented by a single transmittance T and a degree of polarization P of the following formula P>−(10 ^0.929 T ^−42.4 −1)×100 (where T<42.3), Or
It is preferable to be configured to satisfy the condition of P≧99.9 (where T≧42.3). The polarizer configured so as to satisfy the above conditions has the performance uniquely required as a display for a liquid crystal television using a large display element. Specifically, the contrast ratio is 1000:1 or more and the maximum brightness is 500 cd/m ² or more. As another application, for example, it is attached to the viewing side of the organic EL display device.

On the other hand, the polarizer configured so as to satisfy the above conditions is thin (for example, 12 μm or less in thickness) because the polymer (for example, polyvinyl alcohol-based molecule) constituting the polarizer has high orientation. The tensile breaking stress in the direction orthogonal to the absorption axis direction of the polarizer is significantly reduced. As a result, for example, when exposed to a mechanical shock exceeding the tensile breaking stress in the manufacturing process of the polarizing film, nano slits are very likely to occur in the absorption axis direction of the polarizer. Therefore, the present invention is particularly suitable for a one-sided protective polarizing film that employs the polarizer (or a one-sided protective polarizing film with an adhesive layer using the same).

As the thin polarizer, among manufacturing methods including a step of stretching in the state of a laminated body and a step of dyeing, in that it can be stretched at a high magnification and the polarization performance can be improved, Japanese Patent No. 4751486 Specification, Patent Those obtained by a production method including a step of stretching in a boric acid aqueous solution as described in Japanese Patent No. 47514881 and Japanese Patent No. 4815544 are preferable, and particularly described in Japanese Patent Nos. 4751481 and 4815544. What is obtained by a production method including a step of auxiliary stretching in the air before stretching in a boric acid aqueous solution is preferable. These thin polarizers can be obtained by a production method including a step of stretching a polyvinyl alcohol-based resin (hereinafter, also referred to as PVA-based resin) layer and a stretching resin base material in a laminate state and a dyeing step. According to this manufacturing method, even if the PVA-based resin layer is thin, it can be stretched without trouble such as breakage due to stretching because it is supported by the stretching resin base material.

<Protective film>
As a material forming the protective film, a material having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy and the like is preferable. For example, polyester-based polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose-based polymers such as diacetyl cellulose and triacetyl cellulose, acrylic-based polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile-styrene copolymer (AS resin). Examples thereof include a polymer and a polycarbonate polymer. Further, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene/propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers. , Polyethersulfone-based polymer, polyetheretherketone-based polymer, polyphenylene sulfide-based polymer, vinyl alcohol-based polymer, vinylidene chloride-based polymer, vinyl butyral-based polymer, arylate-based polymer, polyoxymethylene-based polymer, epoxy-based polymer, or the above Blends of polymers and the like are also mentioned as examples of the polymer forming the protective film.

The protective film may contain one or more kinds of any appropriate additive. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a release agent, an anti-coloring agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment and a coloring agent. The content of the thermoplastic resin in the protective film is preferably 50 to 100% by weight, more preferably 50 to 99% by weight, further preferably 60 to 98% by weight, and particularly preferably 70 to 97% by weight. When the content of the thermoplastic resin in the protective film is 50% by weight or less, the high transparency and other properties inherent in the thermoplastic resin may not be sufficiently exhibited.

As the protective film, a retardation film, a brightness enhancement film, a diffusion film or the like can also be used. Examples of the retardation film include those having a front surface retardation of 40 nm or more and/or a thickness direction retardation of 80 nm or more. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a retardation film is used as the protective film, the retardation film also functions as a polarizer protective film, so that the thickness can be reduced.

Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a thermoplastic resin film. The stretching temperature, the stretching ratio, etc. are appropriately set depending on the retardation value, the material of the film, and the thickness.

The thickness of the protective film can be appropriately determined, but is generally about 1 to 500 μm in view of workability such as strength and handleability, and thin layer property. It is particularly preferably 1 to 300 μm, more preferably 5 to 200 μm, further preferably 5 to 150 μm, and particularly preferably 5 to 80 μm.

A functional layer such as a hard coat layer, an antireflection layer, an antisticking layer, a diffusion layer or an antiglare layer may be provided on the surface of the protective film to which the polarizer is not adhered. The hard coat layer, the antireflection layer, the antisticking layer, the functional layer such as the diffusion layer and the antiglare layer may be provided on the protective film itself, or may be provided separately from the protective film. it can.

<Intervening layer>
The protective film and the polarizer are laminated via intervening layers such as an adhesive layer, a pressure-sensitive adhesive layer, and an undercoat layer (primer layer). At this time, it is desirable that both layers are laminated without an air gap by an intervening layer. The protective film and the polarizer are preferably laminated via an adhesive layer.

The adhesive layer is formed of an adhesive. The type of adhesive is not particularly limited, and various types can be used. The adhesive layer is not particularly limited as long as it is optically transparent, and as the adhesive, various forms such as water-based, solvent-based, hot melt-based and active energy ray-curable adhesives are used. Alternatively, an active energy ray-curable adhesive is suitable.

Examples of the water-based adhesive include isocyanate-based adhesives, polyvinyl alcohol-based adhesives, gelatin-based adhesives, vinyl-based latex-based adhesives, and water-based polyesters. The water-based adhesive is usually used as an adhesive composed of an aqueous solution, and usually contains 0.5 to 60% by weight of solid content.

The active energy ray-curable adhesive is an adhesive that is cured by active energy rays such as electron beams and ultraviolet rays (radical curable type, cation curable type), and is, for example, an electron beam curable type or an ultraviolet ray curable type. Can be used. As the active energy ray curable adhesive, for example, a photo radical curable adhesive can be used. When the photoradical-curable active energy ray-curable adhesive is used as an ultraviolet curable adhesive, the adhesive contains a radical-polymerizable compound and a photopolymerization initiator.

The coating method of the adhesive is appropriately selected depending on the viscosity of the adhesive and the desired thickness. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or offset), a bar reverse coater, a roll coater, a die coater, a bar coater, a rod coater and the like. In addition, a method such as a dipping method can be appropriately used for coating.

Further, when the water-based adhesive or the like is used, the application of the adhesive is preferably performed so that the finally formed adhesive layer has a thickness of 30 to 300 nm. The thickness of the adhesive layer is more preferably 60 to 250 nm. On the other hand, when an active energy ray-curable adhesive is used, it is preferable that the adhesive layer has a thickness of 0.1 to 200 μm. The thickness is more preferably 0.5 to 50 μm, further preferably 0.5 to 10 μm.

When laminating the polarizer and the protective film, an easily adhesive layer can be provided between the protective film and the adhesive layer. The easy-adhesion layer can be formed of various resins having a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, a silicone-based, a polyamide skeleton, a polyimide skeleton, a polyvinyl alcohol skeleton, or the like. These polymer resins may be used alone or in combination of two or more. Further, other additives may be added to form the easily adhesive layer. Specifically, a tackifier, a UV absorber, an antioxidant, a stabilizer such as a heat stabilizer and the like may be used.

The easy-adhesion layer is usually provided in advance on the protective film, and the easy-adhesion layer side of the protective film and the polarizer are laminated with an adhesive layer. The easy-adhesion layer is formed by applying a material for forming the easy-adhesion layer onto the protective film by a known technique and drying. The material for forming the easy-adhesion layer is usually prepared as a solution diluted to an appropriate concentration in consideration of the thickness after drying and the smoothness of coating. The easily-adhesive layer has a thickness after drying of preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. A plurality of easy-adhesion layers can be provided, but in this case as well, it is preferable that the total thickness of the easy-adhesion layers be within the above range.

The adhesive layer is formed from an adhesive. As the pressure-sensitive adhesive, various pressure-sensitive adhesives can be used, for example, rubber-based pressure-sensitive adhesives, acrylic pressure-sensitive adhesives, silicone-based pressure-sensitive adhesives, urethane-based pressure-sensitive adhesives, vinyl alkyl ether-based pressure-sensitive adhesives, polyvinylpyrrolidone-based pressure-sensitive adhesives, poly-based pressure-sensitive adhesives. Examples thereof include acrylamide adhesives and cellulose adhesives. An adhesive base polymer is selected according to the type of the adhesive. Among the pressure-sensitive adhesives, an acrylic pressure-sensitive adhesive is preferably used because it is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive property of adhesiveness and is excellent in weather resistance and heat resistance. It

The undercoat layer (primer layer) is formed in order to improve the adhesion between the polarizer and the protective film. The material forming the primer layer is not particularly limited as long as it is a material that exhibits a certain degree of strong adhesion to both the base film and the polyvinyl alcohol-based resin layer. For example, a thermoplastic resin excellent in transparency, thermal stability, stretchability, etc. is used. Examples of the thermoplastic resin include acrylic resins, polyolefin resins, polyester resins, polyvinyl alcohol resins, and mixtures thereof.

<Adhesive layer>
As described above, the pressure-sensitive adhesive layer in the piece protective polarizing film with a pressure-sensitive adhesive layer of the present invention has a storage elastic modulus at −40° C. of 7.0×10 ⁷ Pa or more. The storage elastic modulus at −40° C. of the pressure-sensitive adhesive layer is preferably 8.0×10 ⁷ Pa or more, and more preferably 1.0×10 ⁷ , from the viewpoint of more effectively suppressing the generation of nanoslits. ^{It is 8} Pa or more. On the other hand, from the viewpoint of preventing peeling that occurs when dropping at low temperature, the storage elastic modulus at -40°C of the pressure-sensitive adhesive layer is preferably 1.0 x 10 ¹⁰ Pa or less.

In addition, the pressure-sensitive adhesive layer imparts high elasticity characteristics when an external stress is applied at a high speed, makes the polarizing film difficult to bend, and suppresses the generation of nanoslits more effectively. The peak is preferably −45° C. or higher, more preferably −40° C. or higher, and further preferably −35° C. or higher. On the other hand, the peak of the loss elastic modulus of the pressure-sensitive adhesive layer is usually 0° C. or lower from the viewpoint of preventing the tackiness of the pressure-sensitive adhesive layer from being developed and the pressure-sensitive adhesive layer from being unusable.

When manufacturing a liquid crystal panel or using a liquid crystal display device, external stress may be applied to the pressure-sensitive adhesive layer-attached piece protective polarizing film at a low speed, and it is preferable to suppress nano slits generated at that time. From the same viewpoint as the relationship between the storage modulus in the low temperature region of the pressure-sensitive adhesive layer and the number of generated nanoslits described above, the present inventors have revealed that the storage modulus of elasticity and the nanoslits in the high temperature region of the pressure-sensitive adhesive layer. When the relationship with the number of occurrences was examined, the storage elastic modulus in the high temperature region of the pressure-sensitive adhesive layer, particularly at 85° C., and the number of nanoslits generated when external stress was applied to the pressure-sensitive adhesive layer-attached piece protective polarizing film at a low speed. It was found that there is a correlation. When the storage elastic modulus of the pressure-sensitive adhesive layer at 85° C. is 5.5×10 ⁴ Pa or more, nanoslits that occur when the external stress is applied to the pressure-sensitive adhesive layer-attached polarizing plate protective film at low speed are also suppressed. I found that I can. From the viewpoint of further suppressing the nanoslit, the storage elastic modulus of the pressure-sensitive adhesive layer at 85° C. is preferably 6.0×10 ⁴ Pa or more, more preferably 7.0×10 ⁴ Pa or more. On the other hand, if the storage elastic modulus of the pressure-sensitive adhesive layer at 85° C. is too high, the pressure-sensitive adhesive layer tends to peel off from the polarizer when the polarizer of the one-sided protective polarizing film undergoes dimensional change due to heat shrinkage. Therefore, the storage elastic modulus at 85° C. of the pressure-sensitive adhesive layer is preferably 1.4×10 ⁵ Pa or less, more preferably 1.3×10 ⁵ Pa or less.

Further, the pressure-sensitive adhesive layer of the piece protective polarizing film with a pressure-sensitive adhesive layer of the present invention has an adhesion force of 8 N/25 mm or less at a peeling speed of 300 mm/min and a peeling angle of 90 degrees to a non-alkali glass surface, and an ITO film-coated glass. The adhesive force to the ITO film surface at a peeling speed of 300 mm/min and a peeling angle of 90 degrees is adjusted to 8 N/25 mm or less. Thereby, even when a thin polarizer is used, the polarizing film can be peeled off from the glass substrate or the ITO film provided on the glass substrate without breaking. The adhesive strength of the adhesive layer to the alkali-free glass surface is preferably 7 N/25 mm or less, more preferably 6 N/25 mm or less, and further preferably 5 N/25 mm or less. The adhesive strength of the glass having the ITO film of the pressure-sensitive adhesive layer to the ITO film surface is preferably 7 N/25 mm or less, more preferably 6 N/25 mm or less, and further preferably 5 N/25 mm or less.

The thickness of the pressure-sensitive adhesive layer is not particularly limited and is, for example, about 1 to 100 μm, preferably 2 to 50 μm, more preferably 2 to 40 μm, and further preferably 5 to 35 μm.

An appropriate pressure-sensitive adhesive can be used to form the pressure-sensitive adhesive layer, and the type thereof is not particularly limited. As the adhesive, a rubber adhesive, an acrylic adhesive, a silicone adhesive, a urethane adhesive, a vinyl alkyl ether adhesive, a polyvinyl alcohol adhesive, a polyvinylpyrrolidone adhesive, a polyacrylamide adhesive, Cellulose adhesives and the like can be mentioned.

Among these pressure-sensitive adhesives, those having excellent optical transparency, exhibiting appropriate wettability, cohesiveness and adhesiveness, and excellent weather resistance and heat resistance are preferably used. An acrylic pressure-sensitive adhesive is preferably used to exhibit such characteristics. Hereinafter, the case where an acrylic pressure-sensitive adhesive is used as a material for forming the pressure-sensitive adhesive layer will be described.

As the acrylic pressure-sensitive adhesive, one having a (meth)acrylic polymer having a monomer skeleton of an alkyl(meth)acrylate as a main skeleton as a base polymer can be used. In addition, (meth)acrylate refers to acrylate and/or methacrylate, and has the same meaning as (meth) of the present invention.

The alkyl group of the alkyl (meth)acrylate constituting the main skeleton of the (meth)acrylic polymer has about 1 to 18 carbon atoms, and specific examples of the alkyl (meth)acrylate include methyl (meth)acrylate and ethyl. (Meth)acrylate, propyl (meth)acrylate, isopropyl (meth)acrylate, n-butyl (meth)acrylate, isobutyl (meth)acrylate, pentyl (meth)acrylate, hexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate , Octyl (meth) acrylate, isooctyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (meth) acrylate, dodecyl (meth) acrylate, stearyl (meth) acrylate, etc. Or they can be used in combination.

In order to obtain a pressure-sensitive adhesive layer having the storage elastic modulus, the loss elastic modulus peak, and the adhesive strength, the (meth)acrylic polymer is a monomer unit and has a homopolymer glass transition temperature of less than 0° C. (more 80% by weight or more (more preferably 85% by weight or more, further preferably 90% by weight or more) of alkyl (meth)acrylate (A) having a temperature of preferably -20°C or less, more preferably -40°C or less), and a homo. Alkyl (meth)acrylate (b1) having a glass transition temperature of 0° C. or higher (more preferably 20° C. or higher, further preferably 40° C. or higher) and homopolymers have a glass transition temperature of 0° C. or higher (more preferably 20° C. or higher). C. or higher, more preferably 40.degree. C. or higher), and at least one high Tg monomer (B) selected from the group consisting of (meth)acryloyl group-containing monomers (b2) having a heterocycle in an amount of 0.1 to 0.1. It is preferable to contain 20% by weight (more preferably 1 to 15% by weight, further preferably 2.5 to 10% by weight, still more preferably 4% by weight or more and less than 10% by weight). When the alkyl (meth)acrylate (b1) and the (meth)acryloyl group-containing monomer (b2) are used in combination, the total amount is% by weight.

Examples of the alkyl (meth)acrylate (A) include ethyl acrylate (Tg: -24°C), n-butyl acrylate (Tg: -50°C), n-pentyl methacrylate (Tg: -5°C), n-. Hexyl acrylate (Tg: -57°C), n-hexyl methacrylate (Tg: -5°C), n-octyl acrylate (Tg: -65°C), n-octyl methacrylate (Tg: -20°C), n-nonyl acrylate (Tg: -58°C), n-lauryl acrylate (Tg: -3°C), n-lauryl methacrylate (Tg: -65°C), n-tetradecyl methacrylate (Tg: -72°C), i-propyl acrylate ( Tg: −3° C.), i-butyl acrylate (Tg: −40° C.), i-octyl acrylate (Tg: −58° C.), i-octyl methacrylate (Tg: −45° C.), 2-ethylhexyl acrylate (Tg: -70 degreeC), 2-ethylhexyl methacrylate (Tg:-10 degreeC), etc. are mentioned. These can be used alone or in combination. Among these, it is preferable to use at least one selected from ethyl acrylate, n-butyl acrylate, n-pentyl methacrylate, n-hexyl acrylate, and 2-ethylhexyl acrylate, and it is more preferable to use n-butyl acrylate. .. The Tg (glass transition temperature) in each parenthesis is the Tg of a homopolymer obtained by polymerizing each monomer. The following description is also the same.

Examples of the alkyl (meth)acrylate (b1) include methyl acrylate (Tg: 8°C), methyl methacrylate (Tg: 105°C), ethyl methacrylate (Tg: 65°C), n-propyl acrylate (Tg: 3°C). ), n-propyl methacrylate (Tg: 35° C.), n-pentyl acrylate (Tg: 22° C.), n-tetradecyl acrylate (Tg: 24° C.), n-hexadecyl acrylate (Tg: 35° C.), n- Linear alkyl (meth)acrylates such as hexadecyl methacrylate (Tg:15°C), n-stearyl acrylate (Tg:30°C), and n-stearyl methacrylate (Tg:38°C); t-butyl acrylate (Tg:43). C.), t-butyl methacrylate (Tg: 48° C.), i-propyl methacrylate (Tg: 81° C.), and branched-chain alkyl (meth) acrylates such as i-butyl methacrylate (Tg: 48° C.); cyclohexyl acrylate (Tg : 19° C.), cyclohexyl methacrylate (Tg: 65° C.), isobornyl acrylate (Tg: 94° C.), and cyclic alkyl (meth) acrylates such as isobornyl methacrylate (Tg: 180° C.). These can be used alone or in combination. Of these, at least one selected from methyl acrylate, methyl methacrylate, ethyl methacrylate, isobornyl acrylate, and isobornyl methacrylate is preferably used, and selected from methyl acrylate, methyl methacrylate, and isobornyl acrylate. It is more preferable to use at least one of

The (meth)acryloyl group-containing monomer (b2) has a heterocycle. The heterocycle is not particularly limited, and examples thereof include aziridine ring, azetidine ring, pyrrolidine ring, piperidine ring, piperazine ring, and heteroaliphatic ring such as morpholine ring, pyrrole ring, imidazole ring, pyrazole ring, oxazole ring, isoxazole ring. And a heteroaromatic ring such as a thiazole ring, an isothiazole ring, a pyridine ring, a pyrimidine ring, a pyridazine ring, and a pyrazine ring. The heterocycle may be directly bonded to the (meth)acryloyl group or may be bonded to the (meth)acryloyl group via a connecting group. Of these, a heteroaliphatic ring is preferable, and a morpholine ring is more preferable. Examples of the (meth)acryloyl group-containing monomer (b2) include N-acryloylmorpholine (Tg: 145°C). These can be used alone or in combination. Of these, N-acryloylmorpholine is particularly preferably used.

Into the (meth)acrylic polymer, one or more kinds of various monomers can be introduced by copolymerization for the purpose of improving adhesiveness and heat resistance. Specific examples of such a copolymerization monomer (excluding the (meth)acryloyl group-containing monomer (b2)) include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a nitrogen-containing monomer, and an aromatic group-containing monomer. Can be mentioned.

Examples of the carboxyl group-containing monomer include acrylic acid, methacrylic acid, carboxyethyl (meth)acrylate, carboxypentyl (meth)acrylate, itaconic acid, maleic acid, fumaric acid and crotonic acid. These can be used alone or in combination.

As the hydroxyl group-containing monomer, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate Examples thereof include 10-hydroxydecyl (meth)acrylate, 12-hydroxylauryl (meth)acrylate and (4-hydroxymethylcyclohexyl)-methyl acrylate. These can be used alone or in combination.

Examples of the nitrogen-containing monomer include vinyl monomers having a lactam ring (for example, vinylpyrrolidone monomers such as N-vinylpyrrolidone and methylvinylpyrrolidone, β-lactam ring, δ-lactam ring, and ε-lactam ring). A vinyllactam-based monomer having a lactam ring); a maleimide-based monomer such as maleimide, N-cyclohexylmaleimide or N-phenylmaleimide; (meth)acrylamide, N,N-dimethyl(meth)acrylamide, N,N- Diethyl (meth)acrylamide, N-hexyl (meth)acrylamide, N-methyl (meth)acrylamide, N-butyl (meth)acrylamide, N-butyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methylolpropane (N-Substituted) amide-based monomer such as (meth)acrylamide; aminoethyl (meth)acrylate, aminopropyl (meth)acrylate, N,N-dimethylaminoethyl (meth)acrylate, and (meth)acrylic acid t -Aminoalkyl (meth)acrylate monomers such as butylaminoethyl, 3-(3-pyridinyl)propyl(meth)acrylate; N-(meth)acryloyloxymethylenesuccinimide, N-(meth)acryloyl-6-oxyhexa Succinimide-based monomers such as methylenesuccinimide and N-(meth)acryloyl-8-oxyoctamethylenesuccinimide; cyano (meth)acrylate-based monomers such as acrylonitrile and methacrylonitrile; vinylpyridine, vinylpiperidone, vinylpyrimidine, vinylpiperazine, vinylpyrazine , Vinylpyrrole, vinylimidazole, vinyloxazole, vinylmorpholine, N-vinylcarboxylic acid amides and the like. These can be used alone or in combination.

Examples of the aromatic group-containing monomer include benzyl (meth)acrylate, phenyl (meth)acrylate, and phenoxyethyl (meth)acrylate. These can be used alone or in combination.

In addition to the above monomers, acid anhydride group-containing monomers such as maleic anhydride and itaconic anhydride; caprolactone adducts of acrylic acid; styrenesulfonic acid, allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid , (Meth)acrylamide propane sulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloyloxynaphthalene sulfonic acid, and other sulfonic acid group-containing monomers; and 2-hydroxyethyl acryloyl phosphate and other phosphoric acid group-containing monomers. These can be used alone or in combination.

Furthermore, vinyl-based monomers such as vinyl acetate, vinyl propionate, styrene, α-methylstyrene, and N-vinylcaprolactam; epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate; polyethylene glycol (meth)acrylate; Glycol-based acrylic ester monomers such as polypropylene glycol (meth), methoxyethylene glycol (meth), and methoxy polypropylene glycol (meth); tetrahydrofurfuryl (meth)acrylate, fluorine (meth)acrylate, silicone (meth) ) Acrylic acid ester-based monomers such as acrylate and 2-methoxyethyl acrylate can also be used. These can be used alone or in combination.

From the viewpoint of improving the cohesive force of the (meth)acrylic polymer and more effectively suppressing the generation of the nanoslit, it is selected from the carboxyl group-containing monomer, the hydroxyl group-containing monomer, and the nitrogen-containing monomer. It is preferable to introduce at least one polar monomer (excluding the (meth)acryloyl group-containing monomer (b2)) into the (meth)acrylic polymer by copolymerization, and more preferably the carboxyl group-containing monomer. The hydroxyl group-containing monomer and the nitrogen-containing monomer are introduced into the (meth)acrylic polymer by copolymerization. As the carboxyl group-containing monomer, (meth)acrylic acid is preferable. The hydroxyl group-containing monomer is preferably one or more selected from 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, and 4-hydroxybutyl (meth)acrylate. The nitrogen-containing monomer is preferably a vinyl-based monomer having a lactam ring, more preferably the vinylpyrrolidone-based monomer, and further preferably N-vinylpyrrolidone. By introducing the nitrogen-containing monomer into the (meth)acrylic polymer by copolymerization, the generation of nanoslits can be more effectively suppressed, and the durability of the pressure-sensitive adhesive layer at high temperature and/or high humidity The property (peeling resistance) can be improved.

The (meth)acrylic polymer preferably contains the carboxyl group-containing monomer as a monomer unit in an amount of 0.01 to 2% by weight, more preferably 0.05 to 1% by weight, and further preferably 0.1. It is 1 to 0.3% by weight. By adjusting the content of the carboxyl group-containing monomer within the above range, it is easy to adjust the adhesive force of the pressure-sensitive adhesive layer to the non-alkali glass surface and the adhesive force of the ITO film-coated glass to the ITO film surface to 8 N/25 mm or less. Become.

The (meth)acrylic polymer preferably contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit, more preferably 0.05 to 1% by weight, and even more preferably 0.1. ~ 0.5% by weight. By adjusting the content of the hydroxyl group-containing monomer within the above range, it becomes easy to adjust the adhesive force of the pressure-sensitive adhesive layer to the non-alkali glass surface and the adhesive force of the glass with an ITO film to the ITO film surface to 8 N/25 mm or less. ..

The (meth)acrylic polymer preferably contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit, more preferably 0.5 to 3% by weight, and further preferably 1.5. ~ 3% by weight. By adjusting the content of the nitrogen-containing monomer within the above range, it becomes easy to adjust the adhesive force of the adhesive layer to the non-alkali glass surface and the adhesive force of the ITO film-attached glass to the ITO film surface to 8 N/25 mm or less. ..

The average molecular weight of the (meth)acrylic polymer is not particularly limited, but the weight average molecular weight is preferably about 500,000 to 2,500,000. The (meth)acrylic polymer can be produced by various known methods, and for example, a radical polymerization method such as a bulk polymerization method, a solution polymerization method or a suspension polymerization method can be appropriately selected. As the radical polymerization initiator, various known azo-based or peroxide-based initiators can be used. The reaction temperature is usually about 50 to 80° C., and the reaction time is 1 to 8 hours. Among the above-mentioned production methods, the solution polymerization method is preferable, and ethyl acetate, toluene and the like are generally used as the solvent of the (meth)acrylic polymer.

A cross-linking agent can be added to the pressure-sensitive adhesive. The cross-linking agent can improve the adhesion and durability, and can maintain the reliability at high temperatures and the shape of the adhesive itself. As the cross-linking agent, an isocyanate type, an epoxy type, a peroxide type, a metal chelate type, an oxazoline type or the like can be appropriately used. These cross-linking agents may be used alone or in combination of two or more.

An isocyanate compound is used as the isocyanate crosslinking agent. As the isocyanate compound, tolylene diisocyanate, chlorphenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, isocyanate monomers such as hydrogenated diphenylmethane diisocyanate and these isocyanates Adduct-type isocyanate compound in which a monomer is added to trimethylolpropane; isocyanurate compound, buret type compound, and urethane preform obtained by addition reaction of known polyether polyol, polyester polyol, acrylic polyol, polybutadiene polyol, polyisoprene polyol, etc. Examples include polymer type isocyanates.

The above isocyanate-based cross-linking agents may be used alone or in a mixture of two or more, but the total content is 100% by weight of the base polymer and the above isocyanate-based crosslinking agent. The crosslinking agent is preferably contained in an amount of 0.01 to 2 parts by weight, more preferably 0.02 to 2 parts by weight, further preferably 0.05 to 1.5 parts by weight. preferable. It can be appropriately contained in consideration of cohesive force, prevention of peeling in a durability test, and the like.

Various peroxides are used as the peroxide-based crosslinking agent. Examples of peroxides include di(2-ethylhexyl)peroxydicarbonate, di(4-t-butylcyclohexyl)peroxydicarbonate, di-sec-butylperoxydicarbonate, t-butylperoxyneodecanoate. , T-hexylperoxypivalate, t-butylperoxypivalate, dilauroyl peroxide, di-n-octanoyl peroxide, 1,1,3,3-tetramethylbutylperoxyisobutyrate, 1 , 1,3,3-tetramethylbutylperoxy 2-ethylhexanoate, di(4-methylbenzoyl)peroxide, dibenzoylperoxide, t-butylperoxyisobutyrate, and the like. Among these, di(4-t-butylcyclohexyl)peroxydicarbonate, dilauroyl peroxide, and dibenzoyl peroxide, which are particularly excellent in crosslinking reaction efficiency, are preferably used.

The above-mentioned peroxides may be used alone or in a mixture of two or more, but the total content is 100 parts by weight of the base polymer, It is 0.01 to 2 parts by weight, preferably 0.04 to 1.5 parts by weight, more preferably 0.05 to 1 parts by weight. In order to adjust workability, reworkability, cross-linking stability, releasability, etc., it is appropriately selected within this range.

Further, the adhesive may contain a silane coupling agent. The durability can be improved by using the silane coupling agent. As the silane coupling agent, one having any appropriate functional group can be used. Specifically, examples of the functional group include a vinyl group, an epoxy group, an amino group, a mercapto group, a (meth)acryloxy group, an acetoacetyl group, an isocyanate group, a styryl group, and a polysulfide group. Specifically, for example, vinyl group-containing silane coupling agents such as vinyltriethoxysilane, vinyltripropoxysilane, vinyltriisopropoxysilane, and vinyltributoxysilane; γ-glycidoxypropyltrimethoxysilane, γ-glycine Epoxy group-containing silane coupling agents such as cidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane; γ-aminopropyltrimethoxysilane, N-β-(aminoethyl)-γ-aminopropylmethyldimethoxysilane, N-(2-aminoethyl)3-aminopropylmethyldimethoxysilane, γ-triethoxysilyl-N-(1,3-dimethylbutylidene) Amino group-containing silane coupling agents such as propylamine and N-phenyl-γ-aminopropyltrimethoxysilane; mercapto group-containing silane coupling agents such as γ-mercaptopropylmethyldimethoxysilane; styryl such as p-styryltrimethoxysilane Group-containing silane coupling agent; (meth)acryl group-containing silane coupling agent such as γ-acryloxypropyltrimethoxysilane and γ-methacryloxypropyltriethoxysilane; isocyanate group-containing silane such as 3-isocyanatepropyltriethoxysilane Coupling agents; polysulfide group-containing silane coupling agents such as bis(triethoxysilylpropyl) tetrasulfide and the like.

The silane coupling agent may be used alone or in combination of two or more kinds, but the total content is 100 parts by weight of the base polymer and the silane coupling agent. The amount is preferably 0.001 to 5 parts by weight, more preferably 0.01 to 1 part by weight, even more preferably 0.02 to 1 part by weight, and further preferably 0.05 to 0.6 part by weight.

Further, the pressure-sensitive adhesive preferably contains a rework improving agent from the viewpoint of improving reworkability. The rework improver is a chemical substance having a polar group, which easily interacts with the glass interface and is easily segregated at the glass interface. Examples of the rework improver include diols having an alkyleneoxy group such as EO and PO, oligomers having a perfluoroalkyl group, and polyether compounds having a reactive silyl group. As the polyether compound, for example, those disclosed in JP 2010-275522 A can be used.

Examples of the polyether compound having a reactive silyl group include MS polymers S203, S303, S810; SILYL EST250, EST280; SAT10, SAT200, SAT220, SAT350, SAT400, EXCESTAR S2410, S2420 manufactured by Asahi Glass Co., Ltd. Or S3430 etc. are mentioned.

The content of the rework improver is preferably 0.001 part by weight or more, more preferably 0.01 part by weight or more, and still more preferably 0.1 part by weight or more, based on 100 parts by weight of the base polymer. It is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, still more preferably 2 parts by weight or less, still more preferably 1 part by weight or less. When the content of the rework improver is less than 0.001 part by weight, the reworkability of the pressure-sensitive adhesive layer is difficult to improve, and when it exceeds 10 parts by weight, the pressure-sensitive adhesive property of the pressure-sensitive adhesive layer tends to deteriorate.

Further, the pressure-sensitive adhesive preferably contains an antistatic agent. When a pressure-sensitive adhesive layer-attached protective polarizing film is attached to a liquid crystal panel during the production of a liquid crystal display device, the release film is peeled from the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached protective polarizing film. Static electricity is generated by peeling. Further, when a sticking layer-attached protective polarizing film is bonded to a liquid crystal panel, if a bonding error occurs, the polarizing film needs to be peeled off, but static electricity is generated by peeling off the polarizing film. .. The generated static electricity influences the alignment of the liquid crystal inside the liquid crystal display device and causes a defect. Further, when the liquid crystal display device is used, display unevenness may occur due to static electricity. By adding an antistatic agent to the pressure-sensitive adhesive, it is possible to impart an antistatic function to the pressure-sensitive adhesive layer of the pressure-sensitive adhesive layer-attached piece protective polarizing film and prevent these problems.

The antistatic agent is not particularly limited, and examples thereof include ionic compounds such as onium-anion salts and alkali metal salts. It is considered that when the ionic compound is added, the ionic compound bleeds out on the surface of the pressure-sensitive adhesive layer, so that the antistatic function is efficiently exhibited. On the other hand, when the ionic compound comes into contact with the polarizer, the optical properties such as the degree of polarization may deteriorate. From the viewpoint of suppressing the deterioration of the optical properties, it is particularly preferable to use an alkali metal salt.

As the alkali metal salt, an organic salt or inorganic salt of an alkali metal can be used. The alkali metal salts may be used alone or in combination of two or more.

Examples of the alkali metal ion forming the cation portion of the alkali metal salt include lithium, sodium and potassium ions. Among these alkali metal ions, lithium ion is preferable.

The anion part of the alkali metal salt may be composed of an organic material or an inorganic material. Examples of the anion moiety constituting the organic salt include CH ₃ COO ⁻ , CF ₃ COO ⁻ , CH ₃ SO ₃ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , (CF ₃ SO ₂ ). ^{_{3 C -, C 4 F 9}} SO 3 -, (C 2 F 5 SO 2) 2 N -, C 3 F 7 COO -, (CF 3 SO 2) (CF 3 CO) N -, - O 3 S ( CF ₂ ) ₃ SO ₃ ⁻ , PF ₆ ⁻ , CO ₃ ²⁻ , and the like are used. In particular, the anion moiety containing a fluorine atom is preferably used because an ionic compound having a good ion dissociation property can be obtained. As the anion part constituting the inorganic salt, 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. Examples of the anionic ^{_{portion, (CF 3 SO 2) 2}} N -, (C 2 F 5 SO 2) 2 N - etc. (perfluoroalkyl sulfonyl) imide are preferable, and _{(CF 3 SO 2) 2 N} -, in formula (Trifluoromethanesulfonyl)imide is preferred.

Specific examples of the alkali metal organic salt include sodium acetate, sodium alginate, sodium ligninsulfonate, sodium toluenesulfonate, LiCF ₃ SO ₃ , Li(CF ₃ SO ₂ ) ₂ N, and Li(CF ₃ SO _{2 ) 2 N, Li (C 2} F 5 SO 2) 2 N, Li (C 4 F 9 SO 2) 2 N, Li (CF 3 SO 2) 3 C, KO 3 S (CF 2) 3 SO 3 K, _{LiO 3 S (CF 2) 3} SO 3 K , and the like, among these _{LiCF 3 SO 3, Li (CF} 3 SO 2) 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 _{F 9 SO 2) 2 N,} Li (CF 3 SO 2) 3 C and the like are _{preferable, Li (CF 3 SO 2)} 2 N, Li (C 2 F 5 SO 2) 2 N, Li (C 4 F 9 SO ₂ ) A fluorine-containing lithium imide salt such as ₂ N is more preferable, and a (perfluoroalkylsulfonyl)imide lithium salt is particularly preferable.

Examples of the inorganic salt of alkali metal include lithium perchlorate and lithium iodide.

The content of the alkali metal salt in the adhesive is preferably 0.001 to 5 parts by weight with respect to 100 parts by weight of the base polymer. If the amount of the alkali metal salt is less than 0.001 part by weight, the effect of improving the antistatic performance may not be sufficient. The amount of the alkali metal salt is preferably 0.01 part by weight or more, and more preferably 0.1 part by weight or more. On the other hand, if the amount of the alkali metal salt is more than 5 parts by weight, the durability may be insufficient. The amount of the alkali metal salt is preferably 3 parts by weight or less, more preferably 1 part by weight or less.

As a method for forming the pressure-sensitive adhesive layer, for example, the pressure-sensitive adhesive is applied to a release-treated separator or the like, and after the pressure-sensitive adhesive layer is formed by drying and removing the polymerization solvent, the polarizer side of the one-sided protective polarizing film ( In the embodiment of FIG. 1, it is produced by a method of transferring to a polarizer) or a method of applying the pressure-sensitive adhesive and drying and removing a polymerization solvent to form a pressure-sensitive adhesive layer on the polarizer side. When applying the pressure-sensitive adhesive, one or more solvents other than the polymerization solvent may be newly added as appropriate.

A silicone release liner is preferably used as the release-treated separator. In the step of forming the pressure-sensitive adhesive layer by coating the pressure-sensitive adhesive of the present invention on such a liner and drying the pressure-sensitive adhesive, a suitable method can be adopted depending on the purpose. Preferably, a method of overheating and drying the above coating film is used. The heating and drying temperature is preferably 40°C to 200°C, more preferably 50°C to 180°C, and particularly preferably 70°C to 170°C. By setting the heating temperature in the above range, a pressure-sensitive adhesive having excellent pressure-sensitive adhesive properties can be obtained.

As the drying time, an appropriate time can be adopted as appropriate. The drying time is preferably 5 seconds to 20 minutes, more preferably 5 seconds to 10 minutes, and particularly preferably 10 seconds to 5 minutes.

Various methods are used for forming the pressure-sensitive adhesive layer. Specifically, for example, roll coat, kiss roll coat, gravure coat, reverse coat, roll brush, spray coat, dip roll coat, bar coat, knife coat, air knife coat, curtain coat, lip coat, die coater, etc. Examples of the method include an extrusion coating method.

When the pressure-sensitive adhesive layer is exposed, the pressure-sensitive adhesive layer may be protected by a release-treated sheet (separator) until practical use.

As the constituent material of the separator, for example, a plastic film such as polyethylene, polypropylene, polyethylene terephthalate, and a polyester film, a porous material such as paper, cloth, and non-woven fabric, a net, a foamed sheet, a metal foil, and a laminate of these are appropriately used. The thin film may be a thin film, but a plastic film is preferably used because of its excellent surface smoothness.

The plastic film is not particularly limited as long as it is a film capable of protecting the pressure-sensitive adhesive layer, and examples thereof include polyethylene film, polypropylene film, polybutene film, polybutadiene film, polymethylpentene film, polyvinyl chloride film and vinyl chloride. Examples thereof include polymer films, polyethylene terephthalate films, polybutylene terephthalate films, polyurethane films, ethylene-vinyl acetate copolymer films and the like.

The thickness of the separator is usually 5 to 200 μm, preferably 5 to 100 μm. In the separator, if necessary, a silicone-based, fluorine-based, long-chain alkyl-based or fatty acid amide-based release agent, release and antifouling treatment with silica powder or the like, coating type, kneading type, vapor deposition type It is also possible to perform antistatic treatment such as. Particularly, by appropriately performing a peeling treatment such as a silicone treatment, a long-chain alkyl treatment, or a fluorine treatment on the surface of the separator, the peelability from the pressure-sensitive adhesive layer can be further enhanced.

<Surface protection film>
The piece protective polarizing film with an adhesive layer may be provided with a surface protective film. The surface protective film usually has a substrate film and a pressure-sensitive adhesive layer, and protects the polarizer through the pressure-sensitive adhesive layer.

As the base material film of the surface protection film, a film material having isotropic property or close to isotropic property is selected from the viewpoints of inspection property and manageability. Examples of the film material include polyester resin such as polyethylene terephthalate film, cellulose resin, acetate resin, polyether sulfone resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, acrylic resin. Examples include transparent polymers such as resins. Of these, polyester resins are preferred. The base film may be used as a laminate of one or two or more film materials, or a stretched product of the film may be used. The thickness of the substrate film is generally 500 μm or less, preferably 10 to 200 μm.

The pressure-sensitive adhesive for forming the pressure-sensitive adhesive layer of the surface protective film includes a (meth)acrylic polymer, silicone-based polymer, polyester, polyurethane, polyamide, polyether, fluorine-based or rubber-based polymer as a base polymer. Can be appropriately selected and used. From the viewpoint of transparency, weather resistance, heat resistance, etc., an acrylic pressure-sensitive adhesive containing an acrylic polymer as a base polymer is preferable. The thickness of the adhesive layer (dry film thickness) is determined according to the required adhesive force. It is usually about 1 to 100 μm, preferably 5 to 50 μm.

In the surface protection film, a release treatment layer can be provided on the surface of the base film opposite to the surface provided with the pressure-sensitive adhesive layer, using a low-adhesion material such as silicone treatment, long-chain alkyl treatment, or fluorine treatment. ..

<Other optical layers>
The pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention can be used as an optical film laminated with another optical layer in practical use. The optical layer is not particularly limited, but for example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wave plate such as 1/2 or 1/4), and a viewing angle compensation film. One or two or more optical layers that may be used can be used. In particular, a reflective polarizing film or a semi-transmissive polarizing film obtained by laminating a reflective plate or a semi-transmissive reflective plate on the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention, and further a phase difference in the pressure-sensitive adhesive layer-attached piece protective polarizing film. An elliptically polarizing film or a circularly polarizing film in which plates are laminated, a wide viewing angle polarizing film in which a viewing angle compensation film is further laminated on a pressure-sensitive adhesive layer-attached protective film, or a pressure-sensitive adhesive layer-attached polarizing film is further brightened. A polarizing film in which an improvement film is laminated is preferable.

The optical film obtained by laminating the optical layer on the pressure-sensitive adhesive layer-attached piece protective polarizing film can also be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like, but it is preliminarily laminated with the optical film. These are excellent in quality stability and assembling work, and have the advantage that the manufacturing process of liquid crystal display devices can be improved. Appropriate adhesion means such as an adhesive layer may be used for lamination. When the above-mentioned pressure-sensitive adhesive layer-attached piece protective polarizing film and other optical films are adhered, their optical axes can be arranged at appropriate angles depending on the intended retardation characteristics and the like.

The piece protective polarizing film with an adhesive layer or the optical film of the present invention can be preferably used for forming various image display devices such as liquid crystal display devices and organic EL display devices. The liquid crystal display device can be formed in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling a liquid crystal cell, a pressure-sensitive adhesive layer-attached piece protective polarizing film or an optical film, and optionally a component such as an illumination system and incorporating a drive circuit. In the present invention, there is no particular limitation except that the pressure-sensitive adhesive layer-attached piece protective polarizing film or optical film according to the present invention is used, and any conventional method can be applied. As the liquid crystal cell, any type such as IPS type and VA type may be used, but the IPS type is particularly preferable.

It is possible to form an appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive layer-attached piece protective polarizing film or an optical film is arranged on one side or both sides of a liquid crystal cell, or one using a backlight or a reflector for an illumination system. it can. In that case, the piece protective polarizing film with an adhesive layer or the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When the pressure-sensitive adhesive layer-attached piece protective polarizing film or the optical film is provided on both sides, they may be the same or different. Furthermore, when forming a liquid crystal display device, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusion plate, a backlight, and other appropriate components are provided at appropriate positions in a single layer or Two or more layers can be arranged.

<Continuous manufacturing method of image display device>
The image display device, the pressure-sensitive adhesive layer-attached one-piece protective polarizing film of the present invention is rolled out from the roll (roll), the pressure-sensitive adhesive layer-attached one-piece protective polarizing film conveyed by the separator, the pressure-sensitive adhesive layer It is preferably manufactured by a continuous manufacturing method (roll-to-panel method) including a step of continuously bonding to the surface of the image display panel via. Since the pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention is a very thin film, it is cut into sheets (sheet-cutting) and then attached one by one to the image display panel (“sheet-to-panel method”). It is also difficult to handle the sheet when it is transported or attached to the display panel, and the adhesive layer-attached protective polarizing film (sheet) has a large mechanical impact (for example, bending due to adsorption) during these processes. Etc.) will be at a higher risk. In order to reduce such a risk, it is necessary to separately take measures such as using a thick surface protection film having a thickness of the substrate film of 50 μm or more. On the other hand, according to the roll-to-panel method, the adhesive protective layer-attached protective polarizing film is stably conveyed from the roll to the image display panel by the continuous separator without being cut into sheets (single sheet cutting). Then, since it is directly attached to the image display panel, the risk can be greatly reduced without using a thick surface protection film. As a result, the adhesive layer whose thickness and storage elastic modulus are controlled so as to satisfy a predetermined relational expression can reduce the mechanical impact, and the image display in which the generation of nanoslits is effectively suppressed. High-speed continuous panel production is possible.

FIG. 5 is a schematic view showing an example of a continuous manufacturing system of a liquid crystal display device adopting the roll-to-panel method. As shown in FIG. 5, the continuous manufacturing system 100 of the liquid crystal display device includes a series of transporting sections X for transporting the liquid crystal display panel P, a first polarizing film supply section 101a, a first bonding section 201a, and a second polarizing film supply. The part 101b and the 2nd bonding part 201b are included. The wound body (first roll) 20a of the first adhesive layer-attached protective polarizing film and the wound body (second roll) 20b of the second adhesive layer-attached protective polarizing film are absorbed in the longitudinal direction. A shaft having a shaft and the embodiment described in FIG. 1 is used.

(Transportation part)
The transport unit X transports the liquid crystal display panel P. The transport unit X includes a plurality of transport rollers, a suction plate, and the like. The transport unit X is arranged between the first bonding unit 201a and the second bonding unit 201b so as to switch the layout relationship between the long side and the short side of the liquid crystal display panel P with respect to the transport direction of the liquid crystal display panel P. A replacement unit (for example, the liquid crystal display panel P is horizontally rotated by 90°) 300 is included. Thus, the first adhesive layer-attached piece protective polarizing film 21a and the second adhesive layer-attached piece protective polarizing film 21b can be attached to the liquid crystal display panel P in a crossed Nicol relationship.

(First polarizing film supply unit)
The first polarizing film supply unit 101a continuously feeds the first pressure-sensitive adhesive layer-attached piece protective polarizing film (with a surface protective film) 21a fed from the first roll 20a and conveyed by the separator 5a to the first bonding unit 201a. Supply to. The first polarizing film supply unit 101a includes a first feeding unit 151a, a first cutting unit 152a, a first peeling unit 153a, a first winding unit 154a, a plurality of conveying roller units, an accumulating unit such as a dancer roll, and the like. Have.

The first feeding portion 151a has a feeding shaft on which the first roll 20a is installed, and feeds the strip-shaped pressure-sensitive adhesive layer-attached protective film 21a provided with the separator 5a from the first roll 20a.

The first cutting unit 152a has a cutting unit such as a cutter and a laser device, and a suction unit. The first cutting portion 152a cuts the strip-shaped first adhesive layer-attached piece protective polarizing film 21a in the width direction with a predetermined length while leaving the separator 5a. However, as the first roll 20a, one in which a strip-shaped pressure-sensitive adhesive layer-attached piece protective polarizing film 21a in which a plurality of cut lines are formed in a predetermined length in the width direction is laminated on the separator 5a (optical with slits) When a film roll is used, the first cutting section 152a is unnecessary (the same applies to the second cutting section 152b described later).

The first peeling portion 153a peels the first adhesive layer-attached piece protective polarizing film 21a from the separator 5a by folding the separator 5a inside. A wedge-shaped member, a roller, etc. are mentioned as the 1st exfoliation part 153a.

The first winding unit 154a winds the separator 5a from which the first pressure-sensitive adhesive layer-attached piece protective polarizing film 21a is peeled off. The first winding unit 154a has a winding shaft on which a roll for winding the separator 5a is installed.

(First bonding part)
The first bonding unit 201a includes the liquid crystal display panel P transported by the transport unit X, the first adhesive layer-attached piece protective polarizing film 21a separated by the first release unit 153a, and the first adhesive layer-attached piece. The protective polarizing film 21a is continuously bonded via the pressure-sensitive adhesive layer (first bonding step). The first bonding unit 81 is configured to have a pair of bonding rollers, and at least one of the bonding rollers is a driving roller.

(Second polarizing film supply unit)
The second polarizing film supply unit 101b continuously feeds the second adhesive layer-attached piece protective polarizing film (with the surface protective film) 21b fed from the second roll 20b and conveyed by the separator 5b to the second bonding unit 201b. Supply to. The second polarizing film supply unit 101b includes a second feeding unit 151b, a second cutting unit 152b, a second peeling unit 153b, a second winding unit 154b, and a plurality of conveying roller units, an accumulating unit such as a dancer roll, and the like. Have. The second feeding portion 151b, the second cutting portion 152b, the second peeling portion 153b, and the second winding portion 154b are respectively the first feeding portion 151a, the first cutting portion 152a, the first peeling portion 153a, and the first roll. It has the same configuration and function as the taking section 154a.

(Second bonding part)
The second bonding section 201b includes the liquid crystal display panel P transported by the transport section X, the second adhesive layer-attached piece protective polarizing film 21b separated by the second release section 153b, and the second adhesive layer-attached piece. The protective polarizing film 21b is continuously bonded via the pressure-sensitive adhesive layer (second bonding step). The second bonding unit 201b is configured to have a pair of bonding rollers, and at least one of the bonding rollers is a driving roller.

Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to the examples shown below. In addition, all parts and% in each example are based on weight. All room temperature conditions not specified below are 23° C. and 65% RH.

<Preparation of one-sided protective polarizing film A>
(Production of polarizer)
Amorphous isophthalic acid copolymerized polyethylene terephthalate (IPA copolymerized PET) film (thickness: 100 μm) having a water absorption of 0.75% and a Tg of 75° C. was corona-treated on one side of the base material, and the corona-treated surface was treated with polyvinyl chloride. Alcohol (polymerization degree 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (polymerization degree 1200, acetoacetyl modification degree 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd. An aqueous solution containing the trade name "Gosephimmer Z200") in a ratio of 9:1 was applied and dried at 25°C to form a PVA-based resin layer having a thickness of 11 µm, and a laminate was prepared.
The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 120°C (in-air auxiliary stretching treatment).
Next, the laminated body was immersed in an insolubilizing bath having a liquid temperature of 30° C. (boric acid aqueous solution obtained by mixing 4 parts by weight of boric acid with 100 parts by weight of water) for 30 seconds (insolubilization treatment).
Then, the polarizing plate was immersed in a dyeing bath having a liquid temperature of 30° C. while adjusting the iodine concentration and the immersion time so that the polarizing plate had a predetermined transmittance. In this example, 0.2 part by weight of iodine was added to 100 parts by weight of water, and 1.0 part by weight of potassium iodide was added, and the resultant was immersed for 60 seconds in an aqueous iodine solution (dyeing treatment). ..
Then, it was immersed for 30 seconds in a crosslinking bath at a liquid temperature of 30° C. (an aqueous boric acid solution obtained by mixing 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with 100 parts by weight of water). (Crosslinking treatment).
Then, the laminate was immersed in an aqueous boric acid solution having a liquid temperature of 70° C. (an aqueous solution obtained by mixing 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with 100 parts by weight of water). On the other hand, uniaxial stretching was performed between rolls having different peripheral speeds in the longitudinal direction (longitudinal direction) so that the total stretching ratio was 5.5 times (underwater stretching treatment).
After that, the laminate was immersed in a cleaning bath having a liquid temperature of 30° C. (an aqueous solution obtained by mixing 4 parts by weight of potassium iodide with 100 parts by weight of water) (cleaning treatment).
As described above, an optical film laminate including a polarizer having a thickness of 5 μm and a boric acid content of 16% was obtained. The boric acid content in the polarizer was measured by the following method.

About the obtained polarizer, a Fourier transform infrared spectrophotometer (FTIR) (manufactured by Perkin Elmer, trade name "SPECTRUM2000") was used to measure total reflection attenuation spectroscopy (ATR) using polarized light as measurement light, and boric acid was measured. The intensity of the peak (665 cm ⁻¹ ) and the intensity of the reference peak (2941 cm ⁻¹ ) were measured. The boric acid amount index was calculated from the obtained boric acid peak intensity and the reference peak intensity by the following formula, and further, the boric acid content (% by weight) was determined from the calculated boric acid amount index by the following formula.
(Boric acid content index)=(strength of boric acid peak 665 cm ⁻¹ )/(strength of reference peak 2941 cm ⁻¹ )
(Boric acid content (% by weight))=(Boric acid content index)×5.54+4.1

(Preparation of transparent protective film)
Transparent protective film: A 40 μm-thick (meth)acrylic resin film having a lactone ring structure was subjected to corona treatment on the surface for easy adhesion treatment.

(Preparation of adhesive applied to transparent protective film)
40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO) and 3 parts by weight of a photoinitiator "IRGACURE 819" (manufactured by BASF) were mixed to prepare an ultraviolet curable adhesive.

(Preparation of one-sided protective polarizing film A)
The transparent protective film was laminated on the surface of the polarizer of the optical film laminate while applying the ultraviolet curable adhesive so that the cured adhesive layer had a thickness of 0.5 μm. Ultraviolet rays were irradiated as energy rays to cure the adhesive. Ultraviolet irradiation is performed using a gallium-encapsulated metal halide lamp, irradiation device: Fusion UV Systems, Inc. Light HAMMER 10, bulb: V bulb, peak illuminance: 1600 mW/cm ² , integrated irradiation amount 1000/mJ/cm ² (wavelength 380 to 440 nm). ) Was used, and the illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell. Then, the amorphous PET base material was peeled off to prepare a one-sided protective polarizing film A using a thin polarizer. The single-sided transmittance T and the polarization degree P of the polarizer were measured by the following method using the obtained one-sided protective polarizing film A. The single-sided transmittance T of the polarizer was 42.8% and the polarization degree P of the polarizer was measured. Was 99.99%.

The single transmittance T and the polarization degree P of the polarizer of the obtained one-sided protective polarizing film A were measured using a spectral transmittance measuring device with an integrating sphere (Dot-3c of Murakami Color Research Laboratory).
The degree of polarization P is the transmissivity (parallel transmissivity: Tp) when two identical piece protective polarizing films A are superposed so that their transmissive axes are parallel to each other, and the transmissive axes of both are orthogonal to each other. It is obtained by applying the transmittance (orthogonal transmittance: Tc) in the case of overlapping in this way to the following formula. Polarization degree P(%)={(Tp−Tc)/(Tp+Tc)} ^1/2 ×100
The respective transmittances are shown by the Y value which is the luminosity factor adjusted by the 2 degree visual field (C light source) of JIS Z8701, with 100% of the completely polarized light obtained through the Glan-Teller prism polarizer.

<Preparation of one-sided protective polarizing film B>
A polyvinyl alcohol film having a thickness of 80 μm was stretched up to 3 times while being dyed for 1 minute in an iodine solution having a concentration of 0.3% at 30° C. between rolls having different speed ratios. After that, the film was stretched at 60° C. while being immersed in an aqueous solution containing 4% boric acid and 10% potassium iodide for 0.5 minutes so that the total stretching ratio was 6 times. Then, the film is washed by immersing it in an aqueous solution containing potassium iodide at 30° C. and a concentration of 1.5% for 10 seconds, and then dried at 50° C. for 4 minutes to obtain a polarizer having a thickness of 20 μm. It was A saponified 40 μm acrylic resin film (transparent protective film) was attached to one surface of the polarizer with an adhesive to prepare a single protective polarizing film B.

<Formation of adhesive layer>
(Preparation of acrylic adhesive A)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, n-butyl acrylate 91.8 parts, methyl methacrylate 6 parts, N-vinylpyrrolidone 1.5 parts, acrylic acid 0.2 Parts, and a monomer mixture containing 0.5 parts of 4-hydroxybutyl acrylate. Furthermore, with respect to 100 parts of the monomer mixture (solid content), 0.15 parts of 2,2′-azobisisobutyronitrile as a polymerization initiator was charged together with ethyl acetate, and nitrogen gas was introduced with gentle stirring. After purging with nitrogen, the liquid temperature in the flask was kept at around 60° C. to carry out a polymerization reaction for 7 hours. Then, ethyl acetate was added to the obtained reaction solution to prepare a solution of an acrylic polymer having a weight average molecular weight of 1.3 million and having a solid content concentration adjusted to 20%.

The weight average molecular weight (Mw) of the acrylic polymer was measured using a GPC device (HLC-8220GPC) manufactured by Tosoh Corporation. The measurement conditions are as follows.
Sample concentration: 0.2 mass% (THF solution)
Sample injection volume: 10 μl
Eluent: THF
Flow rate: 0.6 ml/min
Measurement temperature: 40°C
Column: sample column; TSKguardcolumn SuperHZ-H (1) + TSKgel SuperHZM-H (2)
Reference column; TSKgel Super H-RC (1)
Detector: Differential refractometer (RI)
The weight average molecular weight was calculated by polystyrene conversion value.

To 100 parts of the solid content of the prepared acrylic polymer solution, 0.17 parts of an isocyanate-based crosslinking agent (manufactured by Mitsui Chemicals, Inc., trade name "Takenate D160N"), a peroxide-based crosslinking agent (manufactured by NOF Corporation, product) 0.25 parts of the name "Nyper BMT" and 0.2 parts of a silane coupling agent containing an acetoacetyl group (trade name "A-100" manufactured by Soken Chemical Co., Ltd.) are mixed to prepare an acrylic pressure-sensitive adhesive A. did.

(Preparation of acrylic adhesives B to X)
In the preparation of the acrylic pressure-sensitive adhesive A, the acrylic polymer solution was prepared in the same manner except that the monomer composition was changed as shown in Table 1 and the polymerization conditions were adjusted. Was prepared. In addition, in the acrylic adhesives F, G, and O to U, a rework improving agent (manufactured by Kaneka Corporation, product name “SAT10”) was further added to 100 parts of the solid content (acrylic polymer) of the acrylic polymer solution. 0.25 part or 0.1 part was added.

(Formation of adhesive layers A to X)
Next, the prepared acrylic pressure-sensitive adhesives A to X are uniformly applied to the surface of a polyethylene terephthalate film (separator film) treated with a silicone-based release agent with a fountain coater, and the air circulation type constant temperature oven at 155° C. After drying for 1 minute, each pressure-sensitive adhesive layer A to X having a thickness of 20 μm was formed on the surface of each separator film.

The compounds in Table 1 are as follows.
BA: n-butyl acrylate (Tg: -50°C)
MMA: Methyl methacrylate (Tg: 105°C)
MA: methyl acrylate (Tg: 8°C)
IBXA: Isobornyl acrylate (Tg: 94°C)
ACMO:N-acryloylmorpholine (Tg:145°C)
NVP: N-vinylpyrrolidone AA: acrylic acid 4HBA: 4-hydroxybutyl acrylate

Examples 1-22, Comparative Examples 1-4
<Preparation of adhesive protective layered piece protective polarizing film>
The prepared pressure-sensitive adhesive layers A to B were attached to the polarizer side of the prepared one-sided protective polarizing film A or B, to prepare a one-sided protective polarizing film with an adhesive layer.

The following measurements and evaluations were performed on the pressure-sensitive adhesive layer and the piece-protective polarizing film with a pressure-sensitive adhesive layer obtained above. The results are shown in Table 2.

<Measurement of peaks of storage elastic modulus and loss elastic modulus>
The peaks of storage elastic modulus and loss elastic modulus at −40° C. and 85° C. of the produced pressure-sensitive adhesive layers A to X were measured by using a rheometric viscoelasticity spectrometer (trade name: RSA-II). It was The measurement conditions were a frequency of 1 Hz, a sample thickness of 2 mm, a pressure load of 100 g, a heating rate of 5°C/min, and a temperature range of -70°C to 150°C.

<Suppression of nano slits: Guitar pick test>
Sample 11 was prepared by cutting the adhesive layer-attached piece protective polarizing films obtained in Examples and Comparative Examples into a size of 50 mm×150 mm (absorption axis direction was 50 mm). The sample 11 used the surface protection film 6 stuck by the following method on the protection film 2 side.

(Surface protection film for testing)
In a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas introduction tube, and a condenser, 94 parts by mass of 2-ethylhexyl acrylate (2EHA), 1 part by mass of N,N-diethylacrylamide (DEAA), ethoxydiethylene glycol acrylate ( 1 part by mass of EDE), 4 parts by mass of 4-hydroxybutyl acrylate (HBA), 0.2 parts by mass of 2,2′-azobisisobutyronitrile as a polymerization initiator, and 150 parts by mass of ethyl acetate were charged and gently stirred. While introducing nitrogen gas, the temperature of the liquid in the flask was kept at around 60° C. to carry out a polymerization reaction for 5 hours to prepare an acrylic polymer solution (40% by mass). The acrylic polymer had a weight average molecular weight of 570,000 and a glass transition temperature (Tg) of -68°C.
The acrylic polymer solution (40% by mass) was diluted to 20% by mass with ethyl acetate, and 500 parts by mass of this solution (100 parts by mass of solid content) was added to an isocyanurate body of hexamethylene diisocyanate (Nippon Polyurethane Industry Co., Ltd., Coronate). HX:C/HX) 2 parts by mass (solid content 2 parts by mass), dibutyltin dilaurate (1 mass% ethyl acetate solution) 2 parts by mass (solid content 0.02 parts by mass) as a crosslinking catalyst, and mixed and stirred. Then, an acrylic adhesive solution was prepared.
The acrylic pressure-sensitive adhesive solution is applied to a transparent polyethylene terephthalate (PET) film (polyester film) having a thickness of 38 μm and heated at 130° C. for 1 minute to form a pressure-sensitive adhesive layer having a thickness of 15 μm for surface protection. A film was made.

Next, as shown in the conceptual diagram of FIG. 3(A) and the sectional view of FIG. 3(B), the release sheet (separator) is peeled from the sample 11 and the glass plate 20 is interposed via the exposed adhesive layer 4. Pasted on top. Next, a load of 200 g was applied to the center of the sample 11 (surface protection film 6 side) with a guitar pick (manufactured by HISTORY, model number "HP2H(HARD)"), and the absorption axis of the polarizer 1 in the sample 11 was applied. A load of 50 reciprocations was repeated at a distance of 100 mm in the orthogonal direction. The load was applied at one place. The load was applied at high speed (5 m/min) and low speed (1 m/min), respectively.
Then, after leaving the sample 11 in an environment of 80° C. for 1 hour, the presence or absence of light leakage cracks of the sample 11 was confirmed according to the following criteria.
(For high speed)
◎: 0-10 pieces ○: 11-15 pieces △: 16-30 pieces ×: 31 pieces or more (at low speed)
◎: 0 pieces ○: 1-3 pieces △: 4-5 pieces ×: 6 pieces or more

FIG. 4 is an index of the following for confirming cracks (nano slits a) of light leakage in the guitar pick test of the pressure-sensitive adhesive layer-attached piece protective polarizing film 11, and is an example of a microscope photograph of the surface of the polarizing film. In FIG. 4(A), cracks due to light leakage due to the nano slits a are not confirmed. On the other hand, FIG. 4B shows a case where three cracks of light leakage due to the nano slits a are generated by heating in the absorption axis direction of the polarizer. In FIG. 4, a sample in which nanoslits were generated was observed with a differential interference microscope. When taking a picture of the sample, the sample without nanoslits was set under the sample with nanoslits (transmission light source side) so as to be crossed Nicols and observed with transmitted light. ..

<Evaluation of adhesive strength>
The produced polarizing film with an adhesive layer was cut into a length of 120 mm and a width of 25 mm to obtain a sample. The sample was attached to a 0.7 mm-thick non-alkali glass plate (EG-XG, manufactured by Corning Incorporated) using a laminator, and then autoclaved at 50° C. and 5 atm for 15 minutes to completely adhere the sample. The adhesive strength of this sample was measured. The adhesive force is measured by a tensile tester (Autograph SHIMAZU AG-1 1OKN) at a peeling angle of 90° and a peeling speed of 300 mm/min (N/25 mm, measuring length 80 mm). Was obtained by doing. The measurement was performed 200 times at intervals of 1 time/0.5 s, and the average value was used as the measured value. The number of samples was three.
Similarly, the sample was attached to an ITO film of a 0.7 mm thick ITO glass plate using a laminator, and then autoclaved at 50° C. and 5 atm for 15 minutes to completely adhere the sample. The adhesive strength was measured by the same method as described above. The ITO glass plate used is the non-alkali ITO film formed on the alkali-free glass plate used as the adherend in the measurement of the adhesive force of the alkali-free glass. The amorphous ITO film was formed by sputtering. The composition of the amorphous ITO film had a Sn ratio of 3% by weight, and a heating process of 140° C.×60 minutes was performed before the sample was laminated. The Sn ratio of the amorphous ITO film was calculated from the weight of Sn atoms/(weight of Sn atoms+weight of In atoms). And the following criteria evaluated.
◎: 5N/25mm or less ○: 5N/25mm or more, 7N/25mm or less △: 7N/25mm or more, 8N/25mm or less ×: 8N/25mm or more

<Evaluation of reworkability>
The piece protective polarizing film with an adhesive layer produced was cut into 32 inches to prepare a sample. The sample was attached to each of the non-alkali glass plate and the ITO film of the ITO glass plate used for the measurement of the adhesive force by using a laminator, and then autoclaved at 50° C. and 5 atm for 15 minutes to completely adhere them. It was Then, using a rework device, the success rate at the time of reworking under the conditions of a peeling angle of 90° and a peeling speed of 300 mm/min was confirmed. The number of samples was four. And the following criteria evaluated.
◎: Rework 100%
○: Rework 75% or more △: Rework 50% or more ×: Rework 25% or less

<Durability evaluation>
The separator film of the one-sided protective polarizing film with an adhesive layer (37 inches) was peeled off and adhered to a 0.7 mm-thick non-alkali glass (EG-XG, manufactured by Corning Incorporated) using a laminator. Then, autoclave treatment was performed at 50° C. and 0.5 MPa for 15 minutes to completely adhere the polarizing film to the acrylic-free glass. Then, this was put under the conditions of a heating oven (heating) of 80° C. and a constant temperature and humidity machine (humidification) of 60° C./90% RH, and the presence or absence of peeling of the polarizing plate after 500 hours was determined as follows. It was evaluated according to the standard.
A: No peeling was observed at all.
◯: Peeling that could not be visually confirmed was observed.
Δ: Small peeling that can be visually confirmed was recognized.
X: Clear peeling was recognized.

From Table 2, the adhesive layer-attached piece protective polarizing films of Examples 1 to 22 are less prone to cracking when a load is applied at high speed or when a load is applied at low speed, and the alkali-free glass surface It can be seen that the reworkability is good for both of the ITO film surface and the ITO film surface, and the durability (peeling resistance) at high temperature and high humidity is excellent. On the other hand, in the pressure-sensitive adhesive layer-attached polarizing plate protective films of Comparative Examples 1, 2 and 4, it can be seen that many cracks are generated both when the load is applied at high speed and when the load is applied at low speed. Further, it can be seen that the pressure-sensitive adhesive layer-attached protective polarizing film of Comparative Example 3 has poor reworkability with respect to the ITO film surface. Further, it can be seen that the piece protective polarizing films with pressure-sensitive adhesive layers of Examples 6, 7, 12 to 18 in which the pressure-sensitive adhesive layer was blended with a rework improver had improved reworkability. Further, comparing the pressure-sensitive adhesive layer-attached piece protective polarizing film of Example 7 with the pressure-sensitive adhesive layer-attached piece protective polarizing film of Example 18, the pressure-sensitive adhesive was obtained using an acrylic polymer containing a nitrogen-containing monomer as a monomer unit. It can be seen that the piece-protecting polarizing plate with a pressure-sensitive adhesive layer of Example 7 in which a layer is formed is less likely to cause cracks and has more excellent durability (peeling resistance) at high temperature and high humidity. Further, from Example 15 and Example 22, the pressure-sensitive adhesive layer-provided piece protective polarizing film of the present invention is less likely to cause cracks and has good reworkability regardless of whether the thickness of the polarizer is thin or thick. I understand.

The pressure-sensitive adhesive layer-attached piece protective polarizing film of the present invention is used in an image display device such as a liquid crystal display device (LCD) or an organic EL display device by itself or as an optical film in which these are laminated.

DESCRIPTION OF SYMBOLS 1 Polarizer 2 Protective film 3 Adhesive layer etc. 4 Adhesive layer 5, 5a, 5b Separator 6, 6a, 6b Surface protective film 10 One-sided protective polarizing film 11 One-sided protective polarizing film 20a, 20b With an adhesive layer Roll of one-sided protective polarizing film
21a, 21b One-sided protective polarizing film with adhesive layer (with surface protective film)
100 Continuous Manufacturing System for Image Display Device 101a, 101b Polarizing Film Supply Units 151a, 151b Feeding Units 152a, 152b Cutting Units 153a, 153b Peeling Units 154a, 154b Winding Units 201a, 201b Laminating Units 300 Arrangement Changing Units P Image Display Panels X Image display panel transport unit

Claims (17)

A one-sided protective polarizing film having a pressure-sensitive adhesive layer having a pressure-sensitive adhesive layer directly or on a polarizer side of the one-sided protective polarizing film having a protective film only on one side of a polarizer,
The pressure-sensitive adhesive layer has a storage elastic modulus at −40° C. of 7.0×10 ⁷ Pa or more,
The pressure-sensitive adhesive layer contains a (meth) acrylic polymer as a base polymer,
The (meth)acrylic polymer, as a monomer unit,
80% by weight or more of an alkyl (meth)acrylate (A) whose homopolymer has a glass transition temperature of less than 0° C.,
From an alkyl (meth)acrylate (b1) having a homopolymer glass transition temperature of 0° C. or higher and a (meth)acryloyl group-containing monomer (b2) having a heterocycle having a glass transition temperature of 0° C. or higher 0.1 to 15 % by weight of at least one high Tg monomer (B) selected from the group consisting of
0.05 to 2% by weight of a carboxyl group-containing monomer, which is a polar monomer other than the (meth)acryloyl group-containing monomer (b2), a nitrogen-containing monomer, and a hydroxyl group-containing monomer,
Peeling speed of the pressure-sensitive adhesive layer to the alkali-free glass surface, the peeling speed at a peeling speed of 300 mm/min and a peeling angle of 90 degrees is 8 N/25 mm or less, and the peeling speed of the pressure-sensitive adhesive layer to the ITO film surface of the ITO-coated glass. A pressure-sensitive adhesive layer-attached protective polarizing film having an adhesive force of 8 N/25 mm or less at 300 mm/min and a peeling angle of 90 degrees. The pressure-sensitive adhesive layer-attached piece protective polarizing film according to claim 1, wherein the pressure-sensitive adhesive layer has a loss elastic modulus peak of −45° C. or higher. The pressure-sensitive adhesive layer has a storage elastic modulus at 85° C. of 5.5×10 ⁴ Pa or more and 1.4×10 ⁵ Pa or less, and the pressure-sensitive adhesive layer-attached piece protection according to claim 1 or 2. Polarizing film. The pressure-sensitive adhesive layer-attached polarizing plate protective film according to any one of claims 1 to 3, wherein the nitrogen-containing monomer is a vinyl-based monomer having a lactam ring. The piece protective polarizing film with a pressure-sensitive adhesive layer according to claim 4 , wherein the vinyl-based monomer having a lactam ring is a vinylpyrrolidone-based monomer. The piece protective polarizing film with a pressure-sensitive adhesive layer according to claim 5 , wherein the vinylpyrrolidone-based monomer is N-vinylpyrrolidone. The (meth)acrylic polymer contains 0.1 to 5% by weight of the nitrogen-containing monomer as a monomer unit, and the pressure-sensitive adhesive layer-attached polarized light protective film according to any one of claims 1 to 7. the film. The (meth)acrylic polymer contains 0.01 to 1% by weight of the hydroxyl group-containing monomer as a monomer unit, and the pressure-sensitive adhesive layer-attached polarized protective film according to any one of claims 1 to 8 , wherein the film. The pressure-sensitive adhesive layer, pressure-sensitive adhesive layer-attached piece protective polarizing film according to any one of claims 1 to 8, characterized in that it contains a rework improver. The content of the rework improver in the adhesive layer, to claim 9, wherein the is 0.001 to 10 parts by weight per 100 parts by weight of the base polymer, which is a material for forming the pressure-sensitive adhesive layer A piece protective polarizing film with an adhesive layer as described. The polarizer, pressure-sensitive adhesive layer-attached piece protective polarizing film according to any one of claims 1 to 10, wherein the thickness is 12μm or less. The above-mentioned polarizer contains a polyvinyl alcohol-based resin, and the optical characteristics represented by the ^single-piece transmittance T and the degree of polarization P have the following formula P>-(10 ^0.929T-42.4 -1) x 100. (However, T<42.3), or
The piece protective polarized light with an adhesive layer according to any one of claims 1 to 12 , which is configured to satisfy the condition of P≧99.9 (where T≧42.3). the film. The pressure-sensitive adhesive layer-attached protective polarizing film according to any one of claims 1 to 12 , wherein the polarizer contains 25% by weight or less of boric acid based on the total amount of the polarizer. Pressure-sensitive adhesive layer-attached piece protective polarizing film according to any one of claims 1 to 13, characterized in that the separator on the adhesive layer is provided. It is a wound body, The piece protective polarizing film with an adhesive layer of Claim 14 characterized by the above-mentioned. An image display device having a pressure-sensitive adhesive layer-attached piece protective polarizing film according to any one of claims 1 to 13. An image display panel, wherein the pressure-sensitive adhesive layer-attached protective polarizing film unwound from the wound body of the pressure-sensitive adhesive layer-attached protective polarizing film according to claim 15 and conveyed by the separator is provided via the pressure-sensitive adhesive layer. A method for continuously manufacturing an image display device, which includes a step of continuously bonding the surfaces of the image display device.