JP2013170237A - Tacky adhesive composition and tacky adhesive sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a tacky adhesive composition which is excellent in reworkability, and durability in a prescribed environment and exhibits excellent corrosion resistance to metals and to provide a tacky adhesive sheet obtained by using the tacky adhesive composition.SOLUTION: A tacky adhesive composition contains: an acrylic polymer having a crosslinkable functional group as a (A) component; a crosslinking agent as a (B) component; and an organosilsesquioxane compound having a reactive group as a (C) component. The reactive group of the organosilsesquioxane compound is a mercapto group. The content of the organosilsesquioxane compound is 0.001-1.5 pts.wt. based on 100 pts.wt. of the acrylic polymer having the crosslinkable functional group as the (A) component. The tacky adhesive sheet is obtained by using the tacky adhesive composition.

Description

  The present invention relates to an adhesive composition and an adhesive sheet. In particular, the present invention relates to a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive layer excellent in reworkability and durability under a predetermined environment and excellent in corrosion resistance to metals, and a pressure-sensitive adhesive sheet using such a pressure-sensitive adhesive composition.

  Conventionally, in the pressure-sensitive adhesive composition used for optical members such as polarizing plates and window films, the surfaces of different materials such as plastic materials and glass can be bonded with good durability, and when a bonding error occurs. Therefore, it is demanded that the pressure-sensitive adhesive composition can be peeled off without remaining on the glass surface (reworkability).

Here, it is known that a silane coupling agent is added as an adhesive composition used for the above-described applications.
That is, since the silane coupling agent usually has an alkoxysilyl group portion and a binding group portion in one molecule, the alkoxysilyl group portion acts on the glass surface while the bonding group portion. Can react with the polymer or the like in the pressure-sensitive adhesive composition, and can increase the pressure-sensitive adhesive force over time to give the pressure-sensitive adhesive sheet predetermined durability.
For this reason, even if the initial adhesive strength of the pressure-sensitive adhesive sheet is designed to be relatively low, by adding a silane coupling agent, the pressure-sensitive adhesive force can be increased over time, and consequently the reworkability of the pressure-sensitive adhesive sheet. , Durability and compatibility can be achieved.

For example, for the purpose of providing a pressure-sensitive adhesive composition that has good reworkability and is less likely to be lifted or peeled off after being applied for a long time after application of a pressure-sensitive adhesive, it is excellent in durability. A pressure-sensitive adhesive composition containing a predetermined organopolysiloxane as a silane coupling agent together with an organic functional group such as the above has been disclosed (for example, Patent Document 1).
More specifically, a pressure-sensitive adhesive composition containing, as an essential component, an organopolysiloxane containing a plurality of types of alkoxy groups having different numbers of carbon atoms in one molecule is disclosed.

Also, for the purpose of providing an optical film with a pressure-sensitive adhesive used for a liquid crystal display device or the like that has good reworkability and can suppress white spots when it is bonded to a glass substrate and can be lifted and peeled off. An optical film with a pressure-sensitive adhesive comprising a silicone oligomer and an acrylic resin is disclosed (for example, Patent Document 2).
More specifically, an optical film with a pressure-sensitive adhesive comprising a silicone oligomer having a functional group such as a mercapto group or an epoxy group and an alkoxy group and an acrylic resin is disclosed.

On the other hand, for the purpose of providing a resin composition excellent in adhesiveness with an inorganic material such as a metal material, a resin composition containing cage-like silsesquioxane is disclosed (for example, Patent Document 3). .
More specifically, Patent Document 3 discloses that a thermosetting resin that is a cyanate ester resin and a polysulfone resin are used to bond a wiring so as to increase the adhesive strength without roughening the wiring board. A resin composition comprising a certain thermoplastic resin and a cage silsesquioxane represented by the following general formula (2) is disclosed.

In addition, for the purpose of providing an adhesive having good adhesiveness at room temperature and greatly improving the adhesive strength by heating, an adhesive comprising ionizing radiation-sensitive ladder-type polysiloxane as a crosslinking agent. A composition for forming an adhesive is disclosed (for example, Patent Document 4).
More specifically, Patent Document 4 discloses an adhesive forming composition comprising a ladder-type polysilsesquioxane having a functional group such as an epoxy group or a mercapto group as a crosslinking agent. Yes.

In addition, a radical curability having two or more ethylenically unsaturated bonds in the molecule for the purpose of providing a liquid crystal sealant having high curability, low liquid crystal contamination, and an appropriate viscosity for a long time. A liquid crystal sealant containing a resin is disclosed (for example, Patent Document 5).
More specifically, Patent Document 5 discloses a liquid crystal sealant comprising a polyorganosilsesquioxane containing two or more organic groups having an ethylenically unsaturated bond.

International Publication No. 2008/090813 (Claims) JP 2008-176173 A (Claims etc.) JP 2003-49079 A (Claims, paragraphs 0013 to 0032, etc.) JP 2003-238923 A (claims, paragraphs 0015 to 0018, etc.) JP 2009-86291 A (claims, etc.)

However, since the polymer component in the pressure-sensitive adhesive composition disclosed in Patent Documents 1 and 2 contains a considerable amount of acrylic acid having a carboxyl group in the molecule as its constituent component, it can be applied to an adherend such as a liquid crystal cell. There was a problem that the adhesive strength increased excessively after bonding.
Therefore, when acrylic acid is excluded from the constituent components of the polymer in the pressure-sensitive adhesive composition in order to suppress the increase in pressure-sensitive adhesive strength, the durability is likely to be significantly reduced depending on the type of silane coupling agent used and how it is combined. There was a problem that the reworkability became insufficient.

Moreover, since the cyanate ester resin contained in the resin composition disclosed in Patent Document 3 is expensive, it is easily hydrolyzed and has poor tackiness, and therefore contains a caged silsesquioxane compound. Nevertheless, there was a problem that it could not be used for polarizing plates.
In addition, the ladder-type polysilsesquioxane compound contained in the pressure-sensitive adhesive forming composition disclosed in Patent Document 4 is a compound that acts as a crosslinking agent that improves the adhesive strength when irradiated with ionizing radiation. Since ionizing radiation was used, there were many problems in terms of usage and facilities.
Further, the polyorganosilsesquioxane disclosed in the liquid crystal sealing agent disclosed in Patent Document 5 is a radical curable resin for improving the adhesive strength with the substrate, and has no effect as an additive. The problem was seen.

  That is, the silsesquioxane compounds disclosed in Patent Documents 3 to 5 are all crosslinking agents, radical curable resins, and the like, and when added to a predetermined pressure-sensitive adhesive composition, have durability and pressure-sensitive adhesive properties. No function as a silsesquioxane compound to be imparted has been found.

Therefore, the present inventors made extensive efforts in view of the above circumstances, and contained a predetermined organosilsesquioxane compound in a predetermined ratio in an adhesive composition containing an acrylic polymer and a crosslinking agent. As a result, it has been found that a pressure-sensitive adhesive composition having excellent reworkability and durability under a predetermined environment and having excellent corrosion resistance to metals can be obtained, and the present invention has been completed.
That is, an object of the present invention is to provide a pressure-sensitive adhesive composition excellent in reworkability and durability under a predetermined environment, and excellent in corrosion resistance to metals, and a pressure-sensitive adhesive sheet using such a pressure-sensitive adhesive composition. It is in.

  According to the present invention, there is provided a pressure-sensitive adhesive composition comprising an acrylic polymer containing a crosslinkable functional group as the component (A) and a crosslinking agent as the component (B), wherein the reactive group is used as the component (C). A pressure-sensitive adhesive composition comprising an organosilsesquioxane compound having the above is provided, and the above-described problems can be solved.

That is, since the pressure-sensitive adhesive composition of the present invention includes an organosilsesquioxane compound having a reactive group as a component (C) that reacts with a crosslinking agent together with the component (A) and the component (B), For example, excellent durability can be exhibited even under severe conditions such as high-temperature drying conditions, high-temperature and high-humidity conditions, or conditions that are repeatedly exposed to low-temperature conditions and high-temperature conditions.
On the other hand, the adhesive force immediately after bonding to the adherend can be suppressed to a relatively low value, and predetermined reworkability can be obtained.

  Moreover, when comprising the adhesive composition of this invention, it is preferable that the reactive group which the organosilsesquioxane compound which has a reactive group has is a mercapto group.

In constituting the pressure-sensitive adhesive composition of the present invention, the content of the organosilsesquioxane compound having a reactive group is set to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A). Thus, the value is preferably within the range of 0.001 to 1.5 parts by weight.
This is because a uniform interaction can be exhibited with respect to both the pressure-sensitive adhesive and the glass.

In constituting the pressure-sensitive adhesive composition of the present invention, the acrylic polymer containing a crosslinkable functional group as the component (A) is a polymer derived from the following components (a) to (c) as the monomer component. It is preferable that it is characterized.
(A) (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms: 100 parts by weight (b) unsaturated double bond-containing compound having a hydroxyl group in the molecule: 0.5 to 10 parts by weight ( c) Unsaturated double bond-containing compound having a carboxyl group in the molecule: 0 part by weight or 0 to 0.1 part by weight (however, 0 part by weight is not included)
By comprising in this way, the acrylic polymer containing the crosslinkable functional group as the component (A) substantially contains an unsaturated double bond-containing compound having a carboxyl group in the molecule as the monomer component. Therefore, even when the adherend such as a liquid crystal cell has a transparent conductive film formed by metal vapor deposition or the like, it is possible to stably prevent the occurrence of acid corrosion.
In addition, although the component (A) does not substantially contain an unsaturated double bond-containing compound having a carboxyl group in the molecule as a monomer component, for example, high temperature drying conditions or high temperature high humidity conditions Excellent durability can be exhibited even under predetermined harsh conditions such as under or under repeated exposure to low and high temperature conditions.
On the other hand, the adhesive force immediately after bonding to the adherend can be suppressed to a relatively low value, and predetermined reworkability can be obtained.

In constituting the pressure-sensitive adhesive composition of the present invention, the crosslinking agent as the component (B) is an isocyanate-based crosslinking agent, and the content thereof includes a crosslinkable functional group as the component (A). It is preferable to set the value within the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer.
By comprising in this way, the cohesion force in an adhesive composition can be raised, and rework property and durability in a predetermined environment can be improved.

Moreover, when comprising the adhesive composition of this invention, it is preferable to further contain an antistatic agent as (D) component.
By comprising in this way, when the adhesive composition of the present invention is cured and used as an adhesive for film bonding, even if the film is peeled off from the adherend, While generation | occurrence | production can be suppressed effectively, rework property and durability in a predetermined environment can further be improved.

Another aspect of the present invention is derived from a pressure-sensitive adhesive composition comprising an acrylic polymer containing a crosslinkable functional group as the component (A) and a crosslinker as the component (B) on the substrate. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive composition contains an organosilsesquioxane compound having a reactive group as the component (C).
That is, if the pressure-sensitive adhesive sheet of the present invention is provided with a predetermined pressure-sensitive adhesive composition as a pressure-sensitive adhesive layer, it is excellent in reworkability and durability under a predetermined environment, and an adherend such as a liquid crystal cell is subjected to metal deposition or the like. Even if it has the transparent conductive film etc. which were formed by this, generation | occurrence | production of acid corrosion can be prevented stably.

Moreover, when comprising the adhesive sheet of this invention, while a base material is an optical film, it is preferable to provide an adhesive layer in at least one of the said optical film.
By being configured in this way, the pressure-sensitive adhesive sheet has excellent reworkability and durability under a predetermined environment, and has an optical film excellent in corrosion resistance even when the liquid crystal cell has a transparent conductive film. Can be obtained.

Moreover, when comprising the adhesive sheet of this invention, while a base material is a peeling film, it is preferable to laminate | stack another peeling film with respect to the opposite surface of the said peeling film in an adhesive layer.
By comprising in this way, the handleability of an adhesive sheet can be improved.

FIG. 1 is a diagram provided to explain the relationship between the content of organosilsesquioxane compounds having different types of reactive groups and the adhesive strength one day after application. FIG. 2 is a diagram provided for explaining the relationship between the content of organosilsesquioxane compounds having different types of reactive groups and the adhesive strength 21 days after application. FIG. 3 is a diagram provided to explain the relationship between the content of the mercapto group-containing organosilsesquioxane compound and the adhesive strength after 1 day and 21 days after application. FIG. 4 is a diagram for explaining the relationship between the content of the mercapto group-containing organosilsesquioxane compound and the gel fraction. Fig.5 (a)-(d) is a conceptual diagram provided in order to demonstrate the usage aspect of an adhesive composition etc., and the manufacturing method of an adhesive sheet. FIG. 6 is another conceptual diagram for explaining the usage mode of the pressure-sensitive adhesive composition and the like.

[First embodiment]
An embodiment of the present invention is a pressure-sensitive adhesive composition containing an acrylic polymer containing a crosslinkable functional group as the component (A) and a crosslinking agent as the component (B), and reactive as the component (C). A pressure-sensitive adhesive composition comprising an organosilsesquioxane compound having a group.
Hereinafter, a first embodiment of the present invention will be specifically described with reference to the drawings as appropriate.

1. (A) Component: Acrylic polymer containing a crosslinkable functional group (1) Monomer component (1) -1. Monomer component (a)
The acrylic polymer containing a crosslinkable functional group as component (A) contains a (meth) acrylic acid alkyl ester containing an alkyl group having 1 to 20 carbon atoms as a monomer component (a) for polymerization. Is preferred.
This is because when the number of carbon atoms of the alkyl group is larger than 20, the adhesiveness of the resulting pressure-sensitive adhesive composition may decrease due to the orientation and crystallization of the side chains.
Therefore, the carbon number of the alkyl group in the acrylic polymer containing a crosslinkable functional group is more preferably set to a value within the range of 1 to 10, and further preferably set to a value within the range of 4 to 8.

Moreover, as (meth) acrylic acid alkyl ester whose carbon number of an alkyl group is the value within the range of 1-20, for example, (meth) acrylic acid methyl, (meth) acrylic acid ethyl, (meth) acrylic acid propyl , Butyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isooctyl (meth) acrylate, (meth) acrylic acid Examples thereof include decyl and dodecyl (meth) acrylate, myristyl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like alone or in combination of two or more.
In addition, the (meth) acrylic acid ester that is the monomer component (a) is a main component that constitutes the acrylic polymer containing a crosslinkable functional group that is the (A) component, and therefore usually constitutes the (A) component. It is preferably a value of 50% by weight or more of the total monomer component, more preferably a value within the range of 60 to 99.5% by weight, and a value within the range of 85 to 99% by weight. More preferably.

(1) -2 Monomer component (b)
Moreover, it is preferable that the acrylic polymer containing the crosslinkable functional group which is (A) component contains the unsaturated double bond containing compound which has a hydroxyl group in a molecule | numerator as monomer component (b) at the time of superposing | polymerizing.
The reason for this is that the hydrogen group becomes a crosslinkable functional group in the acrylic polymer by including the monomer component (b). That is, when a cross-linking agent is added to the pressure-sensitive adhesive composition, the acrylic polymer containing the functional group as the component (A) can be effectively cross-linked and the cohesive strength of the obtained pressure-sensitive adhesive is improved. It is possible to easily adjust the adhesive force and the storage elastic modulus.

Examples of the unsaturated double bond-containing compound having a hydroxyl group in the molecule include vinyl ethers such as hydroxyethyl vinyl ether, hydroxybutyl vinyl ether, cyclohexyldimethanol monovinyl ether, and allyl ethers such as allyl alcohol, allyl glycol, and allyl diglycol. , 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 3-hydroxybutyl (meth) acrylate , (Meth) acrylic acid 4-hydroxybutyl and other (meth) acrylic acid hydroxyalkyl esters and other monomers are preferably used alone or in combination of two or more.
In view of compatibility with the (meth) acrylate monomer that is the main component constituting the (meth) acrylate polymer, it is more preferably a (meth) acrylate hydroxyalkyl ester, Particularly preferred is 2-hydroxyethyl (meth) acrylate or 4-hydroxybutyl (meth) acrylate.

Moreover, it is preferable to make the compounding quantity of a monomer component (b) into the value within the range of 0.5-10 weight part with respect to 100 weight part of monomer components (a).
The reason for this is that when the amount of the monomer component (b) is less than 0.5 parts by weight, the cross-linking between the components (A) becomes insufficient and the durability under a predetermined environment may deteriorate. Because.
On the other hand, when the compounding amount of the monomer component (b) exceeds 10 parts by weight, the adhesiveness of the adhesive composition may be excessively lowered.
Therefore, the blending amount of the monomer component (b) is more preferably set to a value within the range of 1 to 5 parts by weight with respect to 100 parts by weight of the monomer component (a).

(1) -3 Monomer component (c)
Moreover, the acrylic polymer containing the functional group as the component (A) does not substantially contain an unsaturated double bond-containing compound having a carboxyl group in the molecule as the monomer component (c) at the time of polymerization. It is preferable.
More specifically, the blending amount of the monomer component (c) when polymerizing the acrylic polymer containing a crosslinkable functional group as the component (A) is 100 parts by weight of the monomer component (a) described above. On the other hand, the value is preferably in the range of 0 part by weight or 0 to 0.1 part by weight (however, 0 part by weight is not included).
This is because when the amount of the monomer component (c) exceeds 0.1 parts by weight, an adherend such as a liquid crystal cell has a transparent conductive film formed by metal vapor deposition or the like. This is because it may be difficult to stably prevent the occurrence of acid corrosion.
Moreover, it is because it may become difficult for the adhesive force in an adhesive composition to raise rapidly after bonding with respect to a to-be-adhered body, and to exhibit the stable rework property.
Therefore, even when the monomer component (c) is blended, it is more preferable to set the value within the range of 0.0001 to 0.1 parts by weight with respect to 100 parts by weight of the monomer component (a). Preferably, the value is in the range of 0.001 to 0.05 parts by weight.
The type of monomer component (c) is not particularly limited as long as it is an unsaturated double bond-containing compound having a carboxyl group in the molecule. For example, acrylic acid, methacrylic acid, crotonic acid, Maleic acid, itaconic acid, citraconic acid and the like can be mentioned.

(1) -4 Other monomer components (d)
Moreover, it is also preferable that the acrylic polymer containing the functional group as the component (A) contains a non-crosslinkable group-containing monomer other than (a) as the other monomer component (d) at the time of polymerization.
This is because the acrylic polymer containing the functional group as the component (A) may contain a non-crosslinkable group-containing monomer other than (a), so that the pressure-sensitive adhesive composition may be easily adjusted. It is.
Therefore, when the monomer component (d) is included in the component (A) as a structural unit, the blending amount of the monomer component (d) is usually based on the total monomers constituting the component (A). 49.5% by weight or less, more preferably 5 to 20% by weight.

  Examples of the non-crosslinkable group-containing monomer other than (a) include amide monomers such as vinyl acetate, (meth) acrylamide, and acryloylmorpholine, such as N- (meth) acryloyloxymethylene succinimide, N- Succinimide monomers such as (meth) acryloyl-6-oxyhexamethylenesuccinimide, for example, vinyl monomers such as N-vinylpyrrolidone and styrene, for example, acrylic acid ester monomers such as silicone (meth) acrylate and fluorine (meth) acrylate Etc.

(2) Weight average molecular weight Moreover, it is preferable to make the weight average molecular weight of the acrylic polymer containing the functional group which is (A) component into the value within the range of 1,000,000-2,200,000.
The reason for this is that when the weight average molecular weight is less than 1,000,000, the reworkability and durability of the pressure-sensitive adhesive composition may be insufficient. On the other hand, when the weight average molecular weight exceeds 2,200,000, it may be difficult to suppress a decrease in processability due to an increase in viscosity of the pressure-sensitive adhesive composition.
Therefore, it is more preferable to set the polymerization average molecular weight of the acrylic polymer containing the functional group as the component (A) to a value in the range of 1,200,000 to 1,800,000, and to a value in the range of 1,400,000 to 1,600,000. Further preferred.
In addition, this weight average molecular weight can be measured by the gel permeation chromatography (GPC) method by polystyrene conversion.

2. Component (C): Organosilsesquioxane Compound Having Reactive Group (1) Kind The pressure-sensitive adhesive composition of the present invention includes an organosilsesquioxane compound having a reactive group as component (C). The organosilsesquioxane compound preferably includes a structure represented by the following general formula (1).
The reason for this is that by including a compound having a specific structure as the component (C), a uniform interaction can be exerted on both the pressure-sensitive adhesive and the glass.
Therefore, even when the acrylic polymer having a crosslinkable functional group as the component (A) does not substantially contain an unsaturated double bond-containing compound having a carboxyl group in the molecule as the monomer component, The durability and reworkability in the environment can be improved.

  (In General Formula (1), R is any of a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, an aryl group having 6 to 20 carbon atoms, a halogen atom, or a reactive group. And a plurality of R may be the same or different from each other, but at least one of them is a reactive group, and at least the other one is a hydrogen atom having 1 to 4 carbon atoms. (It is any one of an alkoxy group and a halogen atom, and n is an integer of 2 to 50.)

Moreover, as n, it is preferable that it is an integer of 6-20, and it is more preferable that it is an integer of 8-14.
This is because if n is an integer greater than 50, it may be difficult to adjust the viscosity or the compatibility with other resins and solvents may be deteriorated.
Therefore, by setting the degree of condensation to a value within the above-mentioned range, the organosilsesquioxane has a higher-order structure, does not cause a conformational change, takes a rigid molecular structure, and is an adhesive. This is because a uniform interaction can be exhibited for both glass and glass.

In addition, the reactive group can form a chemical bond (for example, a covalent bond, an ionic bond, etc.) directly or via a crosslinking agent or the like with the crosslinkable functional group in the component (A). It has a functional group. Preferred examples of the functional group include those containing a hydroxyl group, an epoxy group, a mercapto group, and the like. Among these, it is more preferable to contain a mercapto group.
Further, the functional group and the silicon atom may be directly bonded or may be bonded via an alkyl group, an alkoxy group, an aryl group, or the like.
In addition, by including a mercapto group as a reactive group, even if the crosslinkable functional group of the acrylic polymer as the component (A) is a hydroxyl group that is difficult to act with a general silane coupling agent, for example, If an isocyanate-based crosslinking agent is used as the component (B) described later, an excellent coupling effect can be exhibited.
This is because the mercapto group easily forms a thiourethane bond with the isocyanate group of the isocyanate-based crosslinking agent, and the other end of the isocyanate-based crosslinking agent is bonded to the hydroxyl group of the acrylic polymer, so that the component (C) Is presumed to form a hanging structure with an appropriate distance from the acrylic polymer.
Therefore, although the acrylic polymer having a crosslinkable functional group as the component (A) does not substantially contain an unsaturated double bond compound having a carboxyl group in the molecule as the monomer component, The durability and reworkability under a predetermined environment can be improved.

More specifically, as shown in FIG. 1, the relationship between the content of organosilsesquioxane compounds having different types of reactive groups and the adhesive strength one day after application will be described.
That is, in FIG. 1, the content (part by weight) of the organosilsesquioxane compound I (n = 12) having a mercapto group with respect to 100 parts by weight of the component (A) is taken on the horizontal axis, and the vertical axis, Organo having an epoxy group with respect to 100 parts by weight of the component (A) on the characteristic curve A (plot ♦) taking the adhesive strength (N / 25 mm) one day after sticking in the obtained adhesive composition Characteristic curve obtained by taking the content (parts by weight) of silsesquioxane compound II (n = 10), and taking the adhesive strength (N / 25 mm) after 1 day of sticking in the obtained adhesive composition on the vertical axis. The content (parts by weight) of the organosilsesquioxane compound III having an epoxy group (mixture of n = 4 to 6) with respect to 100 parts by weight of the component (A) is taken on B (plot ■) and the horizontal axis. On the vertical axis, the viscosity obtained Adhesive strength after sticking one day in composition and (N / 25 mm) made by taking the characteristic curve C (plot ▲) but are shown respectively.

FIG. 2 illustrates the relationship between the content of organosilsesquioxane compounds having different types of reactive groups and the adhesive strength 21 days after application.
That is, in FIG. 2, the content (parts by weight) of the organosilsesquioxane compound I (n = 12) having a mercapto group with respect to 100 parts by weight of the component (A) is taken on the horizontal axis, and the vertical axis, Organo having an epoxy group with respect to 100 parts by weight of the component (A) on the characteristic curve D (plot ♦) taking the adhesive strength (N / 25 mm) 21 days after sticking in the obtained adhesive composition Characteristic curve obtained by taking the content (parts by weight) of silsesquioxane compound II (n = 10) and taking the adhesive strength (N / 25 mm) 21 days after application in the obtained adhesive composition on the vertical axis E (plot ■) and the horizontal axis, the content (parts by weight) of organosilsesquioxane compound III having an epoxy group (mixture of n = 4 to 6) with respect to 100 parts by weight of component (A), On the vertical axis, obtained Adhesive strength after sticking 21 days in the pressure-sensitive adhesive composition and (N / 25 mm) made by taking the characteristic curve F (plot ▲) but are shown respectively.
In addition, about the composition of an adhesive composition, the measurement conditions of adhesive force, etc., it describes in an Example.

First, as understood from the characteristic curves A and D, the organosilsesquioxane compound I having a mercapto group n of 12 has an adhesive force after 1 day of application as its content increases. The adhesive strength 21 days after application also increased once and then decreased.
On the other hand, as understood from the characteristic curves B and E, the organosilsesquioxane compound II having an epoxy group of n = 10 has an adhesive force after 1 day of application as its content increases. The adhesive strength 21 days after application also decreases.
Moreover, as understood from the characteristic curves C and F, the organosilsesquioxane compound III, which is a mixture of n having an epoxy group of 4 to 6, is one day after application as its content increases. Both the adhesive strength and the adhesive strength 21 days after application are greatly reduced.
Therefore, in order to obtain the required reworkability while maintaining the minimum required adhesive strength as an adhesive composition, the reactive group of the organosilsesquioxane compound as the component (C) is a mercapto. It is understood that it is preferred to contain groups.

(2) Content The content of the organosilsesquioxane compound having a reactive group as the component (C) is 100 parts by weight with respect to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A). A value within the range of 0.001 to 1.50 parts by weight is preferable.
The reason for this is that by setting the content of the organosilsesquioxane compound having a reactive group as the component (C) to a value within such a range, both the pressure-sensitive adhesive and the glass are balanced with each other. This is because the effect can be exhibited.
As a result, reworkability and durability under a predetermined environment can be further improved.
That is, when the content of the component (C) is less than 0.001 part by weight, the absolute amount of the component (C) is insufficient, and it becomes difficult to sufficiently exert its effect. This is because it may be difficult to obtain durability. On the other hand, when the content of the component (C) exceeds 1.5 parts by weight, the uniform interaction is lost for both the pressure-sensitive adhesive and the glass, and the durability and reworkability deteriorate. Because there is.
Therefore, the content of the organosilsesquioxane compound having a reactive group as the component (C) is 0.01 to 1. with respect to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A). A value within the range of 0 part by weight is more preferable, and a value within the range of 0.1 to 0.5 part by weight is even more preferable.

Next, the relationship between the content of the mercapto group-containing organosilsesquioxane compound and the adhesive strength one day after application and 21 days after application will be described with reference to FIG.
That is, in FIG. 3, the horizontal axis represents the content (part by weight) of the mercapto group-containing organosilsesquioxane compound I contained in the general formula (1) with respect to 100 parts by weight of the component (A), and the vertical axis The characteristic curve A (plot ◇) obtained by taking the adhesive strength (N / 25 mm) one day after application in the obtained pressure-sensitive adhesive composition, and the vertical axis, 21 days after application in the obtained pressure-sensitive adhesive composition Characteristic curves D (plots ■) each having an adhesive strength (N / 25 mm) are shown.
In addition, about the composition of an adhesive composition, the measurement conditions of adhesive force, etc., it describes in an Example.

First, as understood from the characteristic curves A and D, as the content of the organosilsesquioxane compound I increases, the adhesive strength after 1 day of pasting and the adhesive strength after 21 days of pasting have once increased. ,is decreasing.
More specifically, in the characteristic curve A, when the content of the organosilsesquioxane compound I is 0 part by weight, the adhesive strength after 1 day of application is 3.4 N / 25 mm. It can be seen that when the content is increased rapidly and the content of Compound I is 0.1 parts by weight, the adhesive strength one day after application shows a value of 5.3 N / 25 mm.
On the other hand, when the content of the compound exceeds 0.1 parts by weight, it can be seen that the adhesive strength after 1 day of sticking begins to decrease gently and continues to decrease thereafter.
In addition, in the characteristic curve D, after 21 days from sticking, the change in the content of the organosilsesquioxane compound I has a great influence on the adhesive strength, and in order to obtain an adhesive strength within a suitable range. It is understood that the content of the organosilsesquioxane compound I is preferably a value within a predetermined range.
More specifically, when the content of the organosilsesquioxane compound I is 0 part by weight, the adhesive strength 21 days after application is 7.8 N / 25 mm. When the content of Compound I is 0.1 parts by weight, it can be seen that the adhesive strength after 21 days of application shows a value of 11.4 N / 25 mm.
On the other hand, when the content of the compound exceeds 0.1 parts by weight, it can be seen that the adhesive strength after 21 days from pasting starts to decrease and continues to decrease thereafter.
Therefore, in order to obtain the predetermined reworkability while maintaining the minimum required adhesive strength as an adhesive composition, the inclusion of an organosilsesquioxane compound having a reactive group as component (C) It is understood that the amount is preferably set to a value in the range of 0.001 to 1.5 parts by weight with respect to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A).

Next, the relationship between the content of the mercapto group-containing organosilsesquioxane compound and the gel fraction will be described with reference to FIG.
That is, in FIG. 4, the content (parts by weight) of the organosilsesquioxane compound I contained in the general formula (1) with respect to 100 parts by weight of the component (A) is taken on the horizontal axis, and The gel fraction (%) in the obtained pressure-sensitive adhesive composition is shown.
In addition, about the composition of an adhesive composition, the measurement conditions of a gel fraction, etc., it describes in an Example.

First, as understood from the characteristic curve, as the content of the organosilsesquioxane compound I increases, the gel fraction increases once and then decreases.
More specifically, when the content of the organosilsesquioxane compound I is 0 part by weight, the gel fraction is 79.6%, but increases rapidly with the increase of compound I, When the content of Compound I is 0.1 parts by weight, it can be seen that the gel fraction shows a value of 81.6%.
On the other hand, when the content of the compound exceeds 0.1 parts by weight, it can be seen that the gel fraction starts to decrease rapidly and continues to decrease thereafter.
Therefore, in order to increase the cohesive force in the pressure-sensitive adhesive composition and improve the reworkability and durability under a predetermined environment, the content of the organosilsesquioxane compound having a reactive group as the component (C), It is understood that a value within the range of 0.001 to 1.5 parts by weight is preferable with respect to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A).

(3) Action effect Here, the effect obtained when the organosilsesquioxane compound I is blended will be described.
More specifically, an organoalkoxysilane compound having a reactive group or an organosiloxane oligomer as a condensate thereof is compared.
An organoalkoxysilane compound having a reactive group has one silicon atom in one molecule. Usually, an alkoxy group bonded to a silicon atom is condensed with a silanol group on the glass surface, and also bonded to a silicon atom. The organic side chain having a functional group causes a condensation reaction or an addition reaction with the crosslinkable functional group in the pressure-sensitive adhesive, and the glass and the pressure-sensitive adhesive are linked by a covalent bond via an organoalkoxysilane compound, thereby providing a strong adhesive effect. To express.
In addition, since the organosiloxane oligomer has more reactive sites per molecule for the crosslinkable functional group in the glass surface and the pressure-sensitive adhesive than the organoalkoxysilane compound, compared with the organoalkoxysilane compound, Although a more powerful effect is expected, the siloxane main chain can take various conformations, so it has a higher-order structure in which organic side chains or alkoxy groups are unevenly distributed in the molecule. I guess that. For example, an example of a higher-order structure is one in which the siloxane main chain forms a helix so that the organic side chain faces outward. In this case, only one of the organosiloxane oligomer that reacts with the crosslinkable functional group in the pressure-sensitive adhesive and the alkoxy group that reacts with the silanol group on the glass surface has a large amount on the surface of the higher order structure. It is presumed that it exists in a biased manner and is more strongly bonded to either the pressure-sensitive adhesive or the glass, and the adhesive effect is relatively weaker than that of the organoalkoxysilane compound.
Therefore, the organosiloxane oligomer can be provided with reworkability without significantly hindering the adhesive effect by adding when the adhesive effect of the pressure-sensitive adhesive is too higher than desired.

On the other hand, the organosilsesquioxane compound I has a rigid molecular structure and does not cause uneven distribution of functional groups due to conformational changes on the surface of the higher order structure.
That is, it has a larger number of effective reaction points per molecule than an organoalkoxysilane compound, and exhibits a more uniform interaction with both an adhesive and glass than an organosiloxane oligomer. Conceivable.
Therefore, the organosilsesquioxane compound added to the pressure-sensitive adhesive composition in order to exert a uniform interaction with both the pressure-sensitive adhesive and the glass is a reactive organic compound for alkoxysilyl groups and silanol groups. The molar ratio of the functional groups is preferably 1.5 to 4.0, and more preferably 2.5 to 3.0.

3. (B) Component: Crosslinking Agent In addition, when the pressure-sensitive adhesive composition of the present invention is constituted, a crosslinking agent is included as the (B) component.
The reason for this is that the acrylic polymer containing the functional group as the component (A) is cross-linked with the crosslinking agent as the component (B), thereby increasing the cohesive force in the pressure-sensitive adhesive composition, reworkability and under a predetermined environment. This is because the durability can be improved.

(1) Kind Moreover, as this crosslinking agent, an isocyanate type crosslinking agent, an aziridine type crosslinking agent, an epoxy-type crosslinking agent, and a metal chelate type crosslinking agent can be mentioned preferably.
This reason is because the adhesive force and storage elastic modulus of an adhesive composition can be adjusted to a more suitable range by including these crosslinking agents.
Among these, it is preferable to use an isocyanate-based crosslinking agent. If it is an isocyanate-based crosslinking agent, the acrylic polymer containing a crosslinkable functional group reacts with the hydroxyl group of the unsaturated double bond-containing compound having a hydroxyl group in the molecule as the monomer component (b), This is because acrylic polymers containing a crosslinkable functional group can be effectively chemically crosslinked.

  Specific examples of such isocyanate crosslinking agents include, for example, trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,2-butylene diisocyanate, 2,3- Aliphatic diisocyanates such as butylene diisocyanate, 1,3-butylene diisocyanate, 2,4,4- or 2,2,4-trimethylhexamethylene diisocyanate, 2,6-diisocyanate methyl caproate, such as 1,3-cyclo Pentane diisocyanate, 1,4-cyclohexane diisocyanate, 1,3-cyclohexane diisocyanate, 3-isocyanate methyl-3,5,5-trimethylcyclohexyl isocyanate 4,4'-methylenebis (cyclohexyl isocyanate), methyl-2,4-cyclohexane diisocyanate, methyl-2,6-cyclohexane diisocyanate, 1,4-bis (isocyanatomethyl) cyclohexane, 1,3-bis (isocyanate methyl) Cycloaliphatic diisocyanates such as cyclohexane, for example m-phenylene diisocyanate, p-phenylene diisocyanate, 4,4′-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, 4,4′-diphenylmethane diisocyanate, 2,4- or 2, Aromatic dii such as 6-tolylene diisocyanate or mixtures thereof, 4,4'-toluidine diisocyanate, dianisidine diisocyanate, 4,4'-diphenyl ether diisocyanate Cyanates such as 1,3- or 1,4-xylylene diisocyanate or mixtures thereof, ω, ω′-diisocyanate-1,4-diethylbenzene, 1,3- or 1,4-bis (1-isocyanate-1- Araliphatic diisocyanates such as methylethyl) benzene or mixtures thereof such as triphenylmethane-4,4 ′, 4 ″ -triisocyanate, 1,3,5-triisocyanatebenzene, 2,4,6-triisocyanate toluene Triisocyanates such as 1,3,5-triisocyanate hexane, for example, polyisocyanate monomers such as 4,4′-diphenyldimethylmethane-2,2′-5,5′-tetraisocyanate, the above-mentioned polyisocyanates Monomers derived dimers, trimers, biurets, alofs Polyisocyanate having 2,4,6-oxadiazinetrione ring obtained from nate, carbon dioxide and the above-mentioned polyisocyanate monomer, such as ethylene glycol, propylene glycol, butylene glycol, neopentyl glycol, 1,6 -Hexane glycol, 3-methyl-1,5-pentanediol, 3,3'-dimethylol heptane, cyclohexanedimethanol, diethylene glycol, triethylene glycol, dipropylene glycol, glycerol, trimethylolpropane, pentaerythritol, sorbitol, etc. Adducts of low molecular weight polyols having a weight average molecular weight of less than 200 to the above-mentioned various isocyanates, for example, polyester polyols having a molecular weight of 200 to 200,000, polyether polyethers, and the like. Ol, polyetherester polyols, polyesteramide polyols, polycaprolactone polyols, polyvalerolactone polyols, acrylic polyols, polycarbonate polyols, polyhydroxy alkanes, castor oil, adducts, and the like to the above-described various isocyanates and polyurethane polyols.

(2) Content Further, the content of the crosslinking agent as the component (B) is in the range of 0.05 to 5 parts by weight with respect to 100 parts by weight of the acrylic polymer containing the crosslinkable functional group as the component (A). It is preferable to set the value within the range.
The reason for this is that when the content of the crosslinking agent is less than 0.05 parts by weight, sufficient cohesion can be obtained when the cohesive force is reduced by the addition of an additive having a specific structure as component (C). This is because it may be difficult to obtain force and storage elastic modulus. On the other hand, when the content of the cross-linking agent exceeds 5 parts by weight, the cross-linking of acrylic polymers containing cross-linkable functional groups as the component (A) becomes excessive, and conversely the adhesive strength decreases. This is because it may be easy.
Therefore, the content of the crosslinking agent as the component (B) is set to a value within the range of 0.05 to 3 parts by weight with respect to 100 parts by weight of the acrylic polymer containing the crosslinkable functional group as the component (A). It is more preferable to set the value within the range of 0.1 to 1 part by weight.

4). Diluting solvent In the pressure-sensitive adhesive composition of the present invention, a solvent is used from the viewpoint of improving the dispersibility of each component or adjusting the viscosity to an appropriate level when the pressure-sensitive adhesive composition is applied to a release film or the like. be able to.
Examples of the solvent include aliphatic hydrocarbons such as hexane and heptane, aromatic hydrocarbons such as toluene and xylene, halogenated hydrocarbons such as methylene chloride and ethylene chloride, alcohols such as methanol, ethanol, propanol, and butanol, Preferred are ketones such as acetone, methyl ethyl ketone, 2-pentanone, isophorone, cyclohexanone, esters such as ethyl acetate and butyl acetate, cellosolv solvents such as ethyl cellosolve, glycol ether solvents such as propylene glycol monomethyl ether, and the like. The concentration of the pressure-sensitive adhesive composition is preferably a value within the range of 10 to 40% by weight.

5. Additives Other additives include tackifiers, antioxidants, UV absorbers, light stabilizers, softeners, fillers, high refractive index agents, diffusing agents, antistatic agents, etc. It is also preferable to contain.
In that case, although depending on the type of the additive, the content is set to a value within the range of 0.1 to 20 parts by weight with respect to 100 parts by weight of the acrylic polymer as the component (A). preferable.

[Second Embodiment]
The 2nd Embodiment of this invention originated in the adhesive composition containing the acrylic polymer containing the crosslinkable functional group as (A) component on a base material, and a crosslinking agent as (B) component. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer, wherein the pressure-sensitive adhesive composition contains an organosilsesquioxane compound having a reactive group as the component (C).
Hereinafter, the second embodiment of the present invention will be specifically described with reference to FIG. 5 with a focus on differences from the first embodiment.

1. Pressure-sensitive adhesive layer The pressure-sensitive adhesive composition can be configured as a pressure-sensitive adhesive layer having predetermined characteristics through the following steps (1) to (3).
(1) Step of preparing a predetermined pressure-sensitive adhesive composition containing components (A), (B) and (C) (2) Applying the pressure-sensitive adhesive composition to a release film to form a coating layer Step (3) Step of cross-linking the pressure-sensitive adhesive composition to make the coating layer a pressure-sensitive adhesive layer Hereinafter, the steps leading to the formation of the pressure-sensitive adhesive layer will be specifically described with reference to the drawings as appropriate.

(1) Step (1) (Preparation step of pressure-sensitive adhesive composition)
Step (1) is a step of preparing a predetermined pressure-sensitive adhesive composition containing the components (A), (B) and (C).
More specifically, it is preferable to dilute the component (A) with a diluting solvent such as ethyl acetate if desired, and add the component (C) with stirring to obtain a uniform mixed solution.
At the same time, after adding the component (B) and, if desired, other additives to the mixed solution, it is diluted as necessary to obtain a desired viscosity while stirring until uniform. It is preferable to obtain a solution of the pressure-sensitive adhesive composition by further adding a solvent.
In addition, since the detail of each component, a mixture ratio, etc. are as having described in 1st Embodiment, it abbreviate | omits.

(2) Step (2) (Applying step of pressure-sensitive adhesive composition)
Step (2) is a step of forming the coating layer 1 by applying the pressure-sensitive adhesive composition to the release film 2 as shown in FIG.
As the release film, for example, a polyester film such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, or a polyolefin film such as polypropylene or polyethylene, a release agent such as silicone resin, fluorine resin, alkyd resin, etc. is applied, The thing which provided the peeling layer is mentioned.
In addition, it is preferable that the thickness of this release film is usually a value within the range of 20 to 150 μm.

Moreover, as a method of applying the pressure-sensitive adhesive composition on the release film, for example, a bar coating method, a knife coating method, a roll coating method, a blade coating method, a die coating method, a gravure coating method, or the like was added. It is preferable to dry after apply | coating an adhesive composition and forming an application layer (coating film).
At this time, the thickness of the coating layer is preferably a value in the range of 5 to 100 μm, more preferably a value in the range of 10 to 50 μm, more preferably in the range of 15 to 30 μm, on the basis of drying. More preferably, the value of
This is because if the coating layer is too thin, sufficient adhesive properties may not be obtained. Conversely, if the coating layer is too thick, the residual solvent may cause a problem.
Moreover, as drying conditions, it is usually preferable to be within a range of 10 seconds to 10 minutes at 50 to 120 ° C.

(3) Step (3) (Coating layer crosslinking step)
Step (3) is a step in which the coating layer of the pressure-sensitive adhesive composition is crosslinked to make the coating layer a pressure-sensitive adhesive layer.
That is, as shown in FIG. 5 (b), the surface of the coating layer 1 in a state of being dried on the release film 2 is cross-linked in a state in which a base material 101 such as an optical film is laminated, and an adhesive layer 10 is preferable.
Or you may make it laminate | stack with respect to base materials, such as an optical film, after the application layer of the adhesive composition apply | coated on the peeling film is previously bridge | crosslinked and used as an adhesive layer.

Moreover, while a base material is a peeling film, the aspect formed by laminating another peeling film with respect to the exposed surface of an adhesive layer is also preferable.
That is, as shown in FIG. 6, after the pressure-sensitive adhesive composition is applied to the release film 2 and dried to form the application layer 1, another release film 2 is laminated on the application layer 1. An adhesive sheet 100b that is sandwiched so that the release layer sides of the two release films 2 are in contact with the adhesive layer 10 by crosslinking is also preferable.
Moreover, after the adhesive sheet 100b of this aspect forms the coating layer 1 of an adhesive composition with respect to the peeling film 2, it is made to dry and bridge | crosslink, another peeling film 2 is used as the adhesive layer 10. The pressure-sensitive adhesive sheet may be sandwiched between two release films 2 by being laminated on the pressure-sensitive adhesive composition.

Moreover, it is preferable that the peeling force in one of two peeling films differs from the peeling force in the other one.
The reason for this is that one of the peelable films can be peeled off without damaging the pressure-sensitive adhesive layer when the obtained pressure-sensitive adhesive sheet is used due to the different peel forces.
Moreover, the adhesive sheet of this aspect peels one peeling film, and sticks the adhesive layer which appeared with respect to base materials, such as an optical film, and makes an optical film etc. a base material. An adhesive sheet can be obtained.
At this time, the surface of the pressure-sensitive adhesive layer can be subjected to surface treatment such as corona treatment, plasma treatment and saponification treatment in order to improve the adhesion to the substrate, if desired.
Such an embodiment is required when only the pressure-sensitive adhesive layer has to be transported, for example, because the production of the pressure-sensitive adhesive layer and the use of the pressure-sensitive adhesive layer are performed in different places.
Moreover, as another aspect, you may obtain an adhesive sheet by forming the coating layer of an adhesive composition directly on base materials, such as an optical film, without passing through a peeling film.
In this case, the exposed surface side of the coating layer of the pressure-sensitive adhesive composition is protected until use by laminating a release film after drying.

In addition, the bridge | crosslinking in the application layer of an adhesive composition is performed through the drying process mentioned above and a seasoning process.
The seasoning process may be performed at 20 to 50 ° C. from the viewpoint of uniformly crosslinking the coating layer of the pressure-sensitive adhesive composition without damaging the coating layer or the base material of the pressure-sensitive adhesive composition. Preferably, it is 23-30 degreeC.
The humidity is preferably 30 to 75% RH, and more preferably 45 to 65% RH.
Furthermore, the period is preferably 3 to 20 days, and more preferably 5 to 14 days.

(4) Adhesive strength Moreover, about the polarizing plate with the adhesive layer which used the base material as the polarizing plate, the adhesive strength after 1 day of sticking to a to-be-adhered body (glass surface) exceeds 1 N / 25mm, and is 10 N / mm or less. A value within the range is preferable.
The reason for this is that when the adhesive strength is 1 N / 25 mm or less, the durability under a predetermined condition may be insufficient. On the other hand, when the adhesive strength exceeds 10 N / 25 mm, the removability may be excessively lowered.
Therefore, it is more preferable that the adhesive strength of the polarizing plate with the pressure-sensitive adhesive layer exceeds 2.5 N / 25 mm and falls within the range of 8 N / 25 mm or less, exceeds 3.5 N / 25 mm, and 5.5 N / More preferably, the value is within a range of 25 mm or less.
For the same reason, the adhesive strength 21 days after application to the adherend is preferably set to a value in the range of 3N / 25mm to 30N / 25mm or less, and 4N / 25mm to 20N. It is more preferable to set the value within a range of 25 mm or less, and it is more preferable to set the value within a range of 15 N / 25 mm or more exceeding 5 N / 25 mm.
In addition, about the measuring method of adhesive force, it describes in an Example.

2. Base material In this invention, it is preferable that the adhesive sheet is formed by providing the adhesive layer mentioned above in at least one of the base materials.
As shown in FIG. 5, the substrate 101 in the pressure-sensitive adhesive sheet 100 of the present invention is not particularly limited. For example, polyvinyl alcohol, polyethylene terephthalate, triacetyl cellulose, polycarbonate, liquid crystal polymer, cycloolefin, polyimide , Polyamide, polyamideimide, polyphenylene ether, polyether ketone, polyether ether ketone, polysulfone, polyether sulfone, polyphenylene sulfide, polyarylate, acrylic resin, alicyclic structure-containing polymer, aromatic polymer, etc. A transparent plastic film is preferred.
Moreover, if it demonstrates from the surface of a use, the optical film used for liquid crystal displays etc., such as a polarizing plate, a polarizing layer protective film, a viewing angle expansion film, an anti-glare film, a phase difference plate, etc. is mentioned preferably.
For example, according to the present invention, even when the substrate is a polarizing plate, the advantage that light leakage can be effectively suppressed can be obtained.
In addition, according to the present invention, the polarizer itself produced by stretching an iodine-containing polyvinyl alcohol resin, which is a raw material of the polarizing plate, can be satisfactorily adhered to the polarizer or the like. The substrate 101 can be obtained. Furthermore, the polarizer etc. with which one side of the polarizer was covered with protective films, such as a triacetyl cellulose and a polyethylene terephthalate, are also object.
In addition, the adhesive sheet when a base material is used as a polarizing plate may be called a polarizing plate with an adhesive layer.

Moreover, there is no restriction | limiting in particular as thickness of a base material, However, Usually, it is preferable to set it as the value within the range of 1-1000 micrometers.
This is because when the thickness of the base material is less than 1 μm, the mechanical strength and handleability may be excessively lowered or it may be difficult to form a uniform thickness. On the other hand, when the thickness of the base material exceeds 1000 μm, the handleability may be excessively lowered or may be economically disadvantageous.
Therefore, the thickness of the base material is more preferably set to a value within the range of 5 to 500 μm, and further preferably set to a value within the range of 10 to 200 μm.
In addition, when a base material is a peeling film, it is preferable to set it as the value within the range of 20-150 micrometers normally.

In addition, from the viewpoint of improving the adhesiveness with the pressure-sensitive adhesive layer, it is also preferable that a surface treatment is performed on the surface side on which the coating layer of the substrate 101 is formed.
Examples of such surface treatment include primer treatment, corona treatment, flame treatment, and saponification treatment, and primer treatment is particularly preferable.
The reason for this is that by using the base material on which such a primer layer is formed, the adhesiveness with the pressure-sensitive adhesive layer can be improved without damaging the base material.
In addition, as a material constituting such a primer layer, cellulose ester (for example, cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose nitrate, and combinations thereof), polyacryl, polyurethane, polyvinyl alcohol , Polyvinyl ester, polyvinyl acetal, polyvinyl ether, polyvinyl ketone, polyvinyl carbazole, polyvinyl butyral, and combinations thereof.
Further, the thickness of the primer layer is not particularly limited, but it is usually preferable to set the value within a range of 0.05 μm to 10 μm.
In addition, as a method of bonding the finally obtained adhesive sheet to a to-be-adhered body, as shown to FIG.5 (c)-(d), first, the peeling film 2 laminated | stacked on the adhesive layer 10 is carried out. Next, it is preferable to bond by sticking the surface of the pressure-sensitive adhesive layer 10 that appears to the adherend 200.

  Hereinafter, the present invention will be described in more detail with reference to examples.

[Example 1]
1. Preparation of pressure-sensitive adhesive composition 100 parts by weight of an acrylic polymer having a crosslinkable functional group as component (A) below, 0.15 parts by weight of a crosslinker as component (B), and organosilsesqui as component (C) A pressure-sensitive adhesive composition consisting of 0.20 part by weight of an oxane compound was prepared.
In addition, the numerical value in Table 1 shows the value converted into solid content.
In Table 1, the blending amount of the monomer component means parts by weight with respect to 100 parts by weight of the whole monomer component.
Furthermore, content of the crosslinking agent as (B) component and the organosilsesquioxane compound as (C) component means the weight part when (A) component is 100 weight part.

(1) Component (A) In a nitrogen atmosphere, 99.0 parts by weight of n-butyl acrylate (BA) as the monomer component (a) and monomer component (b) are contained in the container. 1.0 part by weight of 4-hydroxybutyl acrylate (4HBA), 0.3 part by weight of azobisisobutyronitrile as a polymerization initiator, and 150 parts by weight of ethyl acetate were accommodated.
Next, polymerization was performed at 60 ° C. for 8 hours to obtain an ethyl acetate solution of an acrylic polymer having a weight average molecular weight of 1,500,000 as component (A).
The weight average molecular weight of the acrylic polymer was measured by a gel permeation chromatography method (hereinafter abbreviated as GPC method).
That is, first, a calibration curve was prepared using polystyrene. Hereinafter, the weight average molecular weight is expressed in terms of polystyrene. Then, the concentration of the measuring object such as an acrylic polymer to prepare a 1 wt% tetrahydrofuran (THF) solution, manufactured by Tosoh Corporation, GEL PER MEATION CHROMATOGRAPH HLC-8020 (TSK GEL GMH XL, TSK GEL GMH XL, TSK GEL The weight average molecular weight was measured under the conditions of 40 ° C., THF solvent, 1 ml / min using a triple column composed of G2000 _HXL ). Then, TSK GUARD COLUMN manufactured by Tosoh Corporation was used as a guard column.

(2) About the component (B) The isocyanate-based crosslinking agent (TD-) as the component (B) with respect to 100 parts by weight of the solid content of the acrylic polymer solution having a crosslinkable functional group as the component (A) obtained. 75) (Soken Chemical Co., Ltd., solid content: 75% by weight, ethyl acetate solution) was added in an amount of 0.15 parts by weight in terms of solid content.

(3) Component (C) Further, a mercapto group-containing organosilsesquioxane compound as component (C) with respect to 100 parts by weight of the solid content of the acrylic polymer solution having a crosslinkable functional group as component (A). 0.20 parts by weight of I (HBSQ-105-7) (Arakawa Chemical Industries, Ltd., n = 12) was added simultaneously with the addition of the component (B) described above.
Subsequently, it mixed uniformly and diluted with ethyl acetate so that solid content concentration might be 20 weight%, and the adhesive composition solution was obtained.

2. Application of pressure-sensitive adhesive composition solution Next, the obtained pressure-sensitive adhesive composition solution was applied to the release-treated surface of a release film made of polyethylene terephthalate having a thickness of 38 μm as a release film (manufactured by Lintec Corporation, SP-PET3811). The coated layer was formed by coating using a knife coater so that the thickness after drying was 25 μm.
Next, the obtained coating layer was dried at 90 ° C. for 1 minute, then bonded to a polarizing plate having a thickness of 180 μm, and pressed in an autoclave at 23 ° C. and 0.5 MPa for 20 minutes. A laminate comprising a coating layer of the pressure-sensitive adhesive composition and a polarizing plate was obtained.

3. Seasoning of the pressure-sensitive adhesive composition Next, the obtained laminate was allowed to stand for 7 days (seasoning) under the conditions of 23 ° C. and 50% RH to sufficiently cross-link the pressure-sensitive adhesive composition, and the pressure-sensitive adhesive layer of Example 1 An attached polarizing plate was obtained.

4). Evaluation (1) Evaluation of Adhesive Strength After bonding to the adherend, the adhesive strength of the polarizing plate with the adhesive layer after 1 day and after 21 days was measured.
That is, the obtained polarizing plate with an adhesive layer was cut into a size of 25 mm wide × 100 mm long using a cutting device (manufactured by Hadano Seisakusho Co., Ltd., Super Cutter) to obtain a measurement sample.
Next, after peeling the release film from the obtained measurement sample, it was bonded to alkali-free glass (Corning Co., Ltd., Eagle XG).
Next, the alkali-free glass on which the measurement sample was bonded was put into an autoclave (manufactured by Kurihara Seisakusho Co., Ltd.) and pressurized for 20 minutes under the conditions of 0.5 MPa and 50 ° C., and then at 23 ° C. and 50% RH. The conditions were left for 1 day.
Next, the adhesive strength of the measurement sample was measured under the following conditions using a tensile tester (Orientec Co., Ltd., Tensilon), and evaluated according to the following criteria. The obtained results are shown in Table 1.
Peeling speed: 300 mm / min Peeling angle: 180 °
(Double-circle): The value of adhesive force exceeds 3.5 and is a value of 5.5 N / 25mm or less.
◯: The value of adhesive strength exceeds 2.5 and is a value of 3.5 N / 25 mm or less, or exceeds 5.5 and a value of 8.0 N / 25 mm or less.
(Triangle | delta): The value of adhesive force exceeds 1.0 and is a value of 2.5 N / 25mm or less, or exceeds 8.0 and is a value of 10.0 N / 25mm or less.
X: The value of adhesive strength is a value of 1.0 N / 25 mm or less, or a value exceeding 10.0 N / 25 mm.

Similarly, after pasting the measurement sample to an alkali-free glass, the adhesive strength when it is left for 21 days (504 hours) under the conditions of 23 ° C. and 50% RH is measured, and in accordance with the following criteria: evaluated. The obtained results are shown in Table 1.
A: Adhesive strength value is 5.0 or more and 20 N / 25 mm or less.
(Circle): The value of adhesive force is 3.0 or more and less than 5.0 N / 25mm.
X: The value of the adhesive strength is a value less than 3.0 N / 25 mm or a value exceeding 20 N / 25 mm.

(2) Evaluation of durability The durability of the polarizing plate with the pressure-sensitive adhesive layer under predetermined conditions was evaluated.
That is, the obtained polarizing plate with an adhesive layer was cut into a size of 233 mm × 309 mm using a cutting device (manufactured by Hadano Seisakusho Co., Ltd., Super Cutter) to obtain a measurement sample.
Next, after peeling the release film from the obtained measurement sample, it was bonded to alkali-free glass (Corning Co., Ltd., Eagle XG).
Next, the alkali-free glass on which the measurement sample was bonded was put into an autoclave (manufactured by Kurihara Seisakusho Co., Ltd.), pressurized under conditions of 0.5 MPa and 50 ° C. for 20 minutes, and then dried at 80 ° C. and 60 ° C. / 90% RH, and heat shock (HS) conditions (one cycle is −35 ° C. (30 minutes) / 70 ° C. (30 minutes)) and then allowed to stand for 100 hours.
Next, the state of the measurement sample was observed using a 10-fold magnifier, and durability was evaluated according to the following criteria. The obtained results are shown in Table 1.
(Double-circle): There is no peeling of a polarizing plate at all.
○: There is floating or peeling of 0.5 mm or less from the end. (There is no floating or peeling at a position exceeding 0.5 mm from the end.)
(Triangle | delta): There exists a float and peeling of 1.0 mm or less from an edge part. (There is no lifting or peeling at a position exceeding 1.0 mm from the end.)
X: There exists floating and peeling exceeding 1.0 mm from an edge part.

Similarly, after the measurement sample was bonded to an alkali-free glass, it was put into an autoclave (manufactured by Kurihara Seisakusho Co., Ltd.), pressurized for 20 minutes under the conditions of 0.5 MPa and 50 ° C., and then dried. After putting into each durable condition of 80 degreeC, 60 degreeC / 90% RH, and heat shock (HS) conditions (one cycle is -35 degreeC (30 minutes) / 70 degreeC (30 minutes)), it was left to stand for 500 hours.
Next, the state of the measurement sample was observed using a 10-fold magnifier, and durability was evaluated according to the following criteria. The obtained results are shown in Table 1.
(Double-circle): There is no peeling of a polarizing plate at all.
○: There is floating or peeling of 0.5 mm or less from the end.
(Triangle | delta): There exists a float and peeling of 1.0 mm or less from an edge part.
X: There exists floating and peeling exceeding 1.0 mm from an edge part.

(3) Evaluation of gel fraction The gel fraction of the adhesive composition was evaluated.
That is, according to the process of “2. Application of pressure-sensitive adhesive composition solution” described above, the pressure-sensitive adhesive composition is applied on the release layer of the release film, subjected to heat treatment at 90 ° C. for 1 minute, and then applied to the polarizing plate. Instead, a polyethylene terephthalate release film (SP-PET 3801, manufactured by Lintec Corporation) having a thickness of 38 μm as another release film was bonded to the coating layer so that the release layer was in contact therewith.
Next, the pressure-sensitive adhesive sheet was obtained by allowing the polarizing plate with the pressure-sensitive adhesive layer to stand (seasoning) for 12 days under conditions of 23 ° C. and 50% RH.
Next, the release film on both sides of the obtained pressure-sensitive adhesive sheet is peeled off, about 0.1 g of the pressure-sensitive adhesive composition is taken out and wrapped in Tetron mesh (# 200), and a Soxhlet extraction apparatus (Tokyo Glass Instrument (Tokyo Glass Instrument ( The non-gel content of the pressure-sensitive adhesive composition was extracted using reflux by a fat extractor (manufactured by Co., Ltd.), and the gel fraction was calculated from the ratio to the initial mass. The obtained results are shown in Table 1.

(4) Evaluation of haze value The haze value of the pressure-sensitive adhesive layer was evaluated.
That is, according to the process of “2. Application of pressure-sensitive adhesive composition solution” described above, the pressure-sensitive adhesive composition is applied on the release layer of the release film, subjected to heat treatment at 90 ° C. for 1 minute, and then applied to the polarizing plate. Instead, a polyethylene terephthalate release film (SP-PET 3801, manufactured by Lintec Corporation) having a thickness of 38 μm as another release film was bonded to the coating layer so that the release layer was in contact therewith.
Next, a pressure-sensitive adhesive sheet was obtained by seasoning under the same conditions as when a polarizing plate with a pressure-sensitive adhesive layer was obtained.
Subsequently, the release films on both sides of the obtained pressure-sensitive adhesive sheet are peeled off to make a measurement sample, and the obtained measurement sample is used with an integrating sphere light transmittance measurement device (NDH-2000, manufactured by Nippon Denshoku Industries Co., Ltd.). Then, the diffusion transmittance (Td%) and the total light transmittance (Tt%) were measured while conforming to JIS K 7105, and the haze value was calculated by the following equation (3). The obtained results are shown in Table 1.
Haze value = (Td / Tt) × 100 (3)

[Examples 2 to 4]
In Examples 2 to 4, the content of the mercapto group-containing organosilsesquioxane compound as the component (C) was set to 0.000 parts by weight with respect to 100 parts by weight of the acrylic polymer having a crosslinkable functional group as the component (A). A polarizing plate with an adhesive layer was prepared and evaluated in the same manner as in Example 1 except that the amount was 1 part by weight, 0.3 part by weight, and 1.0 part by weight. The obtained results are shown in Table 1.

[Examples 5 to 7]
In Examples 5 to 7, the mercapto group-containing organosilsesquioxane compound as the component (C) was replaced with an epoxy group-containing organosilsesquioxane compound II (SQ-506 (Arakawa Chemical Industries, Ltd., n = 10). And 0.10 parts by weight, 0.30 parts by weight and 1.00 parts by weight with respect to 100 parts by weight of the acrylic polymer having a crosslinkable functional group as the component (A). Otherwise, a polarizing plate with an adhesive layer was prepared and evaluated in the same manner as in Example 1. Table 1 shows the obtained results.

[Comparative Example 1]
In Comparative Example 1, a polarizing plate with an adhesive layer was prepared and evaluated in the same manner as in Example 1 except that the mercapto group-containing organosilsesquioxane compound as the component (C) was not added. The obtained results are shown in Table 1.

[Comparative Example 2]
In Comparative Example 2, the mercapto group-containing organosilsesquioxane compound as the component (C) is changed to an organoalkoxysilane compound IV (KBM-803 (manufactured by Shin-Etsu Chemical Co., Ltd.)) represented by the formula (4). A polarizing plate with a pressure-sensitive adhesive layer was prepared and evaluated in the same manner as in Example 1 except for the change. The obtained results are shown in Table 1.

[Comparative Example 3]
In Comparative Example 3, the mercapto group-containing organosilsesquioxane compound as the component (C) is converted into a linear siloxane oligomer compound V (X, which is a condensate of the organoalkoxysilane compound represented by the above formula (4). Except for changing to -41-1805 (manufactured by Shin-Etsu Chemical Co., Ltd.), a polarizing plate with an adhesive layer was prepared and evaluated in the same manner as in Example 1. The obtained results are shown in Table 1.

As described above in detail, according to the present invention, the acrylic polymer containing a crosslinkable functional group contains a crosslinker and an organosilsesquioxane compound having a specific structure in a predetermined ratio, thereby allowing reworkability. In addition, a pressure-sensitive adhesive composition having excellent durability under a predetermined environment and excellent corrosion resistance to metals has been obtained.
Therefore, the pressure-sensitive adhesive composition and the like of the present invention can significantly contribute to improving the quality of various films including optical films such as liquid crystal display devices, plasma display devices, organic electroluminescence devices, and inorganic electroluminescence devices. Be expected.

1: coating layer of pressure-sensitive adhesive composition, 2: release film, 10: pressure-sensitive adhesive layer, 100: pressure-sensitive adhesive sheet, 101: base material, 200: adherend

Claims (9)

(A) A pressure-sensitive adhesive composition containing an acrylic polymer containing a crosslinkable functional group as a component and a crosslinking agent as a component (B),
(C) The adhesive composition characterized by including the organosilsesquioxane compound which has a reactive group as a component.   The pressure-sensitive adhesive composition according to claim 1, wherein the organosilsesquioxane compound having a reactive group as the component (C) is a mercapto group-containing organosilsesquioxane compound.   The content of the organosilsesquioxane compound is set to a value in the range of 0.001 to 1.5 parts by weight with respect to 100 parts by weight of the acrylic polymer containing a crosslinkable functional group as the component (A). The pressure-sensitive adhesive composition according to claim 1 or 2. The acrylic polymer containing a crosslinkable functional group as the component (A) is a polymer derived from the following components (a) to (c) as a monomer component. The pressure-sensitive adhesive composition according to claim 1.
(A) (meth) acrylic acid alkyl ester having 1 to 20 carbon atoms: 100 parts by weight (b) unsaturated double bond-containing compound having a hydroxyl group in the molecule: 0.5 to 10 parts by weight ( c) Unsaturated double bond-containing compound having a carboxyl group in the molecule: 0 part by weight or 0 to 0.1 part by weight (however, 0 part by weight is not included)   The crosslinking agent as the component (B) is an isocyanate crosslinking agent, and the content thereof is 0.05 to 100 parts by weight with respect to 100 parts by weight of the acrylic polymer containing a crosslinking functional group as the component (A). It is set as the value within the range of 5 weight part, The adhesive composition as described in any one of Claims 1-4 characterized by the above-mentioned.   (D) Antistatic agent is further included as a component, The adhesive composition as described in any one of Claims 1-5 characterized by the above-mentioned. A pressure-sensitive adhesive sheet having a pressure-sensitive adhesive layer derived from a pressure-sensitive adhesive composition comprising a crosslinkable functional group as a component (A) and a cross-linking agent as a component (B) on a substrate. ,
The pressure-sensitive adhesive sheet, wherein the pressure-sensitive adhesive composition contains an organosilsesquioxane compound having a reactive group as the component (C).   The pressure-sensitive adhesive sheet according to claim 7, wherein the base material is an optical film, and the pressure-sensitive adhesive layer is provided on at least one of the optical films. The pressure-sensitive adhesive sheet according to claim 7, wherein the base material is a release film, and another release film is laminated on the opposite surface of the release film in the pressure-sensitive adhesive layer.

Images