TW201504377A - Adhesive composition, adhesive agent and adhesive sheet - Google Patents

Abstract

To provide an adhesive composition, an adhesive agent and an adhesive sheet, without causing adverse effects on adhered objects such as a transparent conductive film while exhibiting excellent durability, light leakage resistance and deformation resistance in a laminated body including the adhesive agent layer. An adhesive composition is provided, comprising: an (methyl)acrylate polymer (A), as monomer units of the polymer and having a weight-average molecular weight of 1,400,000 to 2,500,000, including a hydroxyl group-containing monomer, an aromatic ring-containing monomer and a carboxyl group-containing monomer; an isocyanate crosslinking agent (B); and a silane coupling agent (C) having a sulfhydryl group. The (methyl)acrylate polymer (A), as monomer unit constituting the polymer, includes 1 to 5 mass% of hydroxyl group-containing monomer, 5 to 30 mass% of aromatic ring-containing monomer and 0.1 to 0.8 mass% of carboxyl group-containing monomer.

Description

Adhesive composition, adhesive and adhesive sheet

The present invention relates to an adhesive composition, an adhesive (a material for bridging an adhesive composition), and an adhesive sheet, and more particularly to an adhesive composition suitable for use as an optical member such as a polarizing plate. Adhesive and adhesive sheet.

In recent years, in various electronic devices, a touch panel having both a display device and an input means has been frequently used. The types of touch panels are mainly resistive, capacitive, optical, and ultrasonic. The resistive touch panel has analog data resistance and mother resistance. The capacitive touch panel has a surface type and a projection type.

The touch panel of mobile electronic devices such as smart phones and tablet terminals that have recently attracted attention has mostly used projection type capacitive touch panels. As a projection type capacitive touch panel of the above mobile electronic device, for example, research has been proposed to laminate a liquid crystal display device (LCD), an adhesive layer, a transparent conductive film (indium tin oxide: ITO), and a glass in order from bottom to top. A touch panel of a protective layer such as a substrate, a transparent conductive film (ITO), or a tempered glass.

As the optical member constituting the liquid crystal display device described above, a liquid crystal module is generally used. In the liquid crystal module, the alignment layer of the two transparent electrode substrates forming the alignment layer is generally disposed inside, and is disposed so as to form a predetermined interval by the spacers, and the periphery thereof is sealed to sandwich the liquid crystal between the two transparent electrode substrates. The components of the material. Usually, outside the two transparent electrode substrates in the liquid crystal module The polarizing plate is bonded by an adhesive.

Here, as described above, in the configuration in which the polarizing plate of the liquid crystal display device is bonded to the transparent conductive film (ITO) through the adhesive layer, the adhesive is directly in contact with the ITO. Therefore, in a large amount of the binder containing the carboxyl group of the acid component, there is a problem that the ITO is corroded or the resistance value of the ITO is changed.

As an adhesive for optics, for example, the adhesive described in Patent Document 1 is known. The adhesive is composed of 50% by mass to 90% by mass of an alkyl ester monomer having 4 to 12 carbon atoms of (meth)acrylic acid and 3 to 10% by mass of an alicyclic alkane of (meth)acrylic acid. a hydroxyalkyl ester monomer of 0.1% by mass to 1.0% by mass of (meth)acrylic acid, and an alkyl ester having 1 to 3 carbon atoms of 3 to 10% by mass of (meth)acrylic acid a copolymer composed of a monomer (total 100% by mass) (the copolymer contains a hydroxyl group, but does not contain a carboxyl group, and has a weight average molecular weight of 700,000 to 1,200,000), and a bridging agent (0.02 mass based on 100 parts by mass of the copolymer) 1 part by mass) and a bridging aid (0.5 parts by mass to 5.0 parts by mass based on 100 parts by mass of the copolymer). Since the adhesive does not contain an acid component carboxyl group, the above problem is less likely to occur.

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open Publication No. 2012-001647

On the other hand, with the thinning of mobile electronic devices in recent years, the constituent member polarizing plates have also begun to be thinned. Specifically, a polarizing plate having a reduced thickness of a protective film that maintains polarized polyvinyl alcohol on both sides is used. The above polarizing plate, Due to the protective film, the ability to prevent thermal contraction of the polarizer is lowered, and the heat shrinkage tends to be larger than the original. In addition, as the material of the protective film, an optical functional film which is likely to be deaerated, such as a cycloolefin polymer (COP), or the like, is used instead of cellulose triacetate. Therefore, among the adhesives used for these, it is required to have higher reliability (durability and light leakage resistance) than now.

However, in the case of using the adhesive of Patent Document 1 in the polarizing plate as described above, the durability is insufficient, and floating or peeling occurs under high temperature conditions or under moist heat conditions. Further, in the adhesive of Patent Document 1, when a thinned polarizing plate generates a large shrinkage stress under heat-resistant conditions, it is difficult to alleviate the shrinkage stress, and light leakage may occur due to displacement of the optical axis, or the liquid crystal module or the like may be deformed. Therefore, there is a case where the display performance of the liquid crystal display device is adversely affected.

The present invention has been made in view of the above circumstances, and it is an object of the invention to provide a laminate which does not adversely affect an adherend such as a transparent conductive film, and which has durability, light leakage resistance, and a laminate including an adhesive layer. Adhesive composition, adhesive, and adhesive sheet excellent in deformability.

In order to achieve the above object, first, the present invention provides an adhesive composition comprising a weight average molecular weight of from 1.4 to 2.5 million, as a monomer unit constituting a polymer, a monomer having a hydroxyl group, and having an aromatic ring. a (meth) acrylate polymer (A) having a monomer, a carboxyl group, an isocyanate bridging agent (B), and a decane coupling agent (C) having a mercapto group, and the above (meth) acrylate polymer ( A), as a monomer unit constituting the polymer, 1% by mass to 5% by mass of the monomer having a hydroxyl group, and 5% by mass to 30% by mass of the above-mentioned aromatic group Monomer of the scented ring, 0.1% by mass to 0.8% by mass of the above monomer having a carboxyl group (Invention 1).

The adhesive obtained by bridging the adhesive composition according to the above invention (Invention 1) is obtained by using the (meth) acrylate polymer (A) as a monomer unit constituting the polymer. A monomer having a hydroxyl group, a monomer having an aromatic ring, a monomer having a carboxyl group, and a decane coupling agent (C) having a mercapto group exhibit excellent coupling effects, durability, light leakage resistance, and an adhesive containing The laminate of the layer is excellent in deformation resistance. In addition, since the amount of the carboxyl group contained in the (meth) acrylate polymer (A) is suppressed to a low level, defects of an adherend such as a transparent conductive film due to an acid can be suppressed.

In the above invention (Invention 1), the isocyanate-based bridging agent (B) is preferably trimethylolpropane-modified methylphenylene diisocyanate (Invention 2).

In the above invention (Invention 1 and Invention 2), the content of the isocyanate-based bridging agent (B) in the adhesive composition is preferably 100 parts by mass based on 100 parts by mass of the (meth)acrylate polymer (A). 0.01 parts by mass to 1 part by mass (Invention 3).

In the above invention (Invention 1 to Invention 3), the content of the decane coupling agent (C) in the adhesive composition is preferably 100 parts by mass based on 100 parts by mass of the (meth) acrylate polymer (A). 0.01 parts by mass to 0.4 parts by mass (Invention 4).

In the above invention (Invention 1 to Invention 4), the monomer having an aromatic ring is preferably 2-phenylethyl (meth)acrylate (Invention 5).

Secondly, the present invention provides an adhesive comprising the above-mentioned adhesive composition (Invention 1 to Invention 5). (Invention 6).

In the above invention (Invention 6), the gel fraction is preferably from 55% to 80% (Invention 7).

Thirdly, the present invention provides a bonding sheet comprising a substrate and an adhesive layer, and the adhesive layer is composed of the above-mentioned adhesive (Invention 6, Invention 7) (Invention 8).

In the above invention (Invention 8), the substrate is preferably an optical member (Invention 9).

In the above invention (Invention 9), the optical member is preferably a polarizing plate (Invention 10).

Fourthly, the present invention provides a bonding sheet comprising two release sheets and an adhesive layer for holding the release sheets in contact with the release faces of the two release sheets, the bonding The agent layer is composed of the above-mentioned binder (Invention 6, Invention 7) (Invention 11).

In the above invention (Invention 8 to Invention 11), the transparent conductive film is used when the laminate of the adhesive layer and the transparent conductive film is exposed to a moist heat promotion test for 500 hours in an atmosphere of 65 ° C and 95% RH. The increase rate of the resistance value calculated by the following formula is preferably 15% or less (Invention 12).

Resistance increase rate (%) = {(RR ₀ ) / R ₀ } × 100 (In the formula, R ₀ is the initial resistance value before the damp heat promotion test, and R is the resistance value after the damp heat promotion test.)

The adhesive composition, the adhesive, and the adhesive sheet according to the present invention do not adversely affect the adherend such as a transparent conductive film, and at the same time, durability, light leakage resistance, and an adhesive layer containing the adhesive. The laminate is excellent in deformation resistance.

1A, 1B‧‧‧bonding strips

1A'‧‧‧Polarizer with adhesive layer

11‧‧‧Adhesive layer

12,12a,12b‧‧‧ peeling film

13‧‧‧Substrate

13’‧‧‧Polar plate

21‧‧‧PET film

21a, 21b‧‧‧

22‧‧‧ITO film

22a‧‧‧ face

23‧‧‧ glass plate

23a‧‧‧ face

24‧‧‧Adhesive tape

25‧‧‧Electrode

30‧‧‧Digital altimeter

S‧‧‧Resistance measurement sample

Fig. 1 is a cross-sectional view showing an adhesive sheet according to a first embodiment of the present invention.

Fig. 2 is a cross-sectional view showing a bonding sheet according to a second embodiment of the present invention.

Fig. 3 is a cross-sectional view showing a sample for measuring a resistance value produced in Test Example 3.

Fig. 4 is a perspective view for explaining a test method of Test Example 3.

Fig. 5 is a view (color) showing the evaluation criteria of the light leakage test (the naked eye) on the polarizing plate with the adhesive layer.

Hereinafter, embodiments of the present invention will be described.

[adhesive composition]

The adhesive composition according to the present embodiment (hereinafter referred to as "adhesive composition P") contains a weight average molecular weight of 1.4 million to 2.5 million, and contains a hydroxyl group as a monomer unit constituting the polymer. Monomer (hydroxyl-containing monomer), monomer having an aromatic ring (containing an aromatic ring monomer), monomer having a carboxyl group (carboxyl-containing monomer), (meth) acrylate polymer (A), isocyanate bridging Agent (B) and a decane coupling agent (C) having a mercapto group. Further, the (meth) acrylate polymer (A) contains, as a monomer unit constituting the polymer, 1% by mass to 5% by mass of a hydroxyl group-containing monomer, and 5% by mass to 30% by mass of an aromatic ring-containing monomer. It contains 0.1% by mass to 0.8% by mass of a carboxyl group-containing monomer. In the present specification, the term "(meth)acrylate" means both acrylate and methacrylate. The same is true for other similar terms. In addition, the concept of "copolymer" is also included in "polymer".

In the above-mentioned adhesive composition P, the (meth) acrylate polymer (A) is contained as a monomer unit constituting the polymer by a predetermined amount. a hydroxyl group-containing monomer, an aromatic ring-containing monomer, and a carboxyl group-containing monomer, and the adhesive agent obtained by bridging the adhesive composition P has both cohesive force and stress relaxation property, durability, light leakage resistance, and viscosity-containing The laminate of the adhesive layer (for example, a touch panel, a liquid crystal panel, or the like) is excellent in deformation resistance (hereinafter, simply referred to as "deformation resistance").

Further, when the above-mentioned adhesive composition P is bridged, the sulfhydryl group of the decane coupling agent (C) and the isocyanate group of the isocyanate-based bridging agent (B) easily form a thiourethane bond, and the isocyanate-based bridging agent The other isocyanate group of (B) reacts with the hydroxyl group of the (meth) acrylate polymer (A) to bridge the (meth) acrylate polymer (A) to form a three-dimensional network structure. Further, it is presumed that the alkoxymethyl decane of the decane coupling agent (C) is suspended from the (meth) acrylate polymer (A) at a suitable distance from the (meth) acrylate polymer (A). Thereby, the excellent coupling effect is exhibited, and the obtained adhesive agent is excellent in adhesive durability even under high temperature conditions and wet heat conditions.

Further, in the above-mentioned adhesive composition P, the content of the carboxyl group-containing monomer contained as a monomer unit is suppressed to a low level by the (meth) acrylate polymer (A), and the obtained adhesion is obtained. The object to be attached is capable of suppressing defects due to acid, and for example, in the case of a transparent conductive film or a metal film, these defects due to acid can be suppressed. In particular, when the attached object is a transparent conductive film, the transparent conductive film can be prevented from being corroded or the resistance value of the transparent conductive film can be changed.

(1) (meth) acrylate polymer (A)

The (meth) acrylate polymer (A) is preferably a monomer unit constituting the polymer, in addition to the above-mentioned hydroxyl group-containing monomer, aromatic ring-containing monomer, and carboxyl group-containing monomer. The alkyl (meth)acrylate having an alkyl group and having 1 to 20 carbon atoms is particularly preferably contained as a main component. Further, other monomers may be contained as needed.

The (meth) acrylate polymer (A) exhibits excellent adhesion as a monomer unit constituting the polymer by an alkyl (meth) acrylate having an alkyl group and having 1 to 20 carbon atoms. Sex. Examples of the (meth)acrylic acid alkyl ester having 1 to 20 carbon atoms in the alkyl group include methyl (meth)acrylate, ethyl (meth)acrylate, and (meth)acrylic acid. Base ester, n-butyl (meth) acrylate, n-pentyl (meth) acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, (meth) acrylate Octyl ester, n-decyl (meth)acrylate, n-dodecyl (meth)acrylate, myristyl (meth)acrylate, cetyl (meth)acrylate, (methyl) ) stearyl acrylate and the like. Among them, from the viewpoint of further improving the adhesion, a (meth) acrylate having an alkyl group having 1 to 8 carbon atoms is preferable, and a methyl (meth) acrylate and a n-butyl (meth) acrylate are particularly preferable. ester. Further, these may be used alone or in combination of two or more.

The (meth) acrylate polymer (A), as a monomer unit constituting the polymer, preferably contains from 50% by mass to 99.9% by mass of an alkyl group having 1 to 20 carbon atoms of (meth)acrylic acid alkyl group. The ester is particularly preferably contained in an amount of from 64.2% by mass to 93% by mass, and more preferably from 80% by mass to 90% by mass. In addition, when 50% by mass or more of the alkyl (meth)acrylate is contained, the (meth) acrylate polymer (A) can be imparted with excellent adhesion. Further, by containing 99.9% by mass or less of the alkyl (meth)acrylate, the other monomer component can be introduced into the (meth)acrylate polymer (A) in a preferred amount.

The (meth) acrylate polymer (A) contains a hydroxyl group-containing monomer as a monomer unit constituting the polymer. The hydroxyl group has high reactivity with the isocyanate group of the isocyanate-based bridging agent (B), and the (meth)acrylate polymer (A) is bridged by the isocyanate-based bridging agent (B) by the reaction thereof. The adhesive obtained by the bridge structure is excellent in durability and deformation resistance.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, and (methyl). A hydroxyalkyl (meth)acrylate such as 2-hydroxybutyl acrylate, 3-hydroxybutyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate. Among them, 2-hydroxyethyl (meth)acrylate or 4-hydroxybutyl (meth)acrylate is preferred from the viewpoint of reactivity with the isocyanate-based bridging agent (B). These may be used alone or in combination of two or more.

The (meth) acrylate polymer (A) contains 1% by mass to 5% by mass of the hydroxyl group-containing monomer as the monomer unit constituting the polymer, and preferably contains 2% by mass to 4% by mass. When the content of the hydroxyl group-containing monomer is in the above range, the bridging structure formed is good, and the obtained adhesive has excellent durability and deformation resistance. When the content of the hydroxyl group-containing monomer is less than 1% by mass, the bridging point is too small, the cohesive force is lowered, and the obtained adhesive does not exhibit excellent durability. On the other hand, when the content of the hydroxyl group-containing monomer exceeds 5% by mass, the bridging point is too large, the obtained adhesive cannot be softened, and the stress relaxation property is lowered, whereby the shrinkage of the substrate and the durability cannot be dealt with. And the deformation resistance is deteriorated.

The (meth) acrylate polymer (A) contains an aromatic ring-containing monomer as a monomer unit constituting the polymer. Thus, the (meth) acrylate polymer (A) has a suitable hardness, and the obtained adhesive is easy to have both cohesive force and It is excellent in strength, durability, and light leakage resistance.

Examples of the aromatic ring-containing monomer include phenyl (meth)acrylate, 2-phenylethyl (meth)acrylate, benzyl (meth)acrylate, and naphthyl (meth)acrylate. , phenoxyethyl (meth)acrylate, phenoxybutyl (meth)acrylate, ethoxylated o-phenylphenol acrylate, phenoxy polyethylene glycol (meth) acrylate, Ethylene oxide modified cresol (meth) acrylate, ethylene oxide (EO) modified nonyl phenol (meth) acrylate, etc., among them, (methyl) is preferred from the viewpoint of improving cohesive force. 2-phenylethyl acrylate. These may be used alone or in combination of two or more.

The (meth) acrylate polymer (A) contains 5% by mass to 30% by mass of the aromatic ring-containing monomer as the monomer unit constituting the polymer, and preferably contains 10% by mass to 25% by mass, particularly preferably Contains 15% by mass to 20% by mass. When the content of the aromatic ring-containing monomer is in the above range, the obtained adhesive has excellent stress relaxation properties, durability, and light leakage resistance. When the content of the aromatic ring-containing monomer is less than 5% by mass, the light leakage resistance of the obtained adhesive is deteriorated. On the other hand, when the content of the aromatic ring-containing monomer exceeds 30% by mass, the amount of the other components is reduced, and the durability of the obtained adhesive is deteriorated.

The (meth) acrylate polymer (A) contains a carboxyl group-containing monomer as a monomer unit constituting the polymer. The carboxyl group promotes the bridging reaction of the hydroxyl group in the (meth)acrylate polymer (A) with the isocyanate bridging agent (B), and the carboxyl group itself also undergoes a bridging reaction with the isocyanate bridging agent (B). The adhesive thus obtained has an appropriate degree of bridging, and the degree of bridging between the (meth) acrylate polymers (A) is uniform, and the durability and the deformation resistance are excellent.

(meth) acrylate polymer (A) as a constituent of the polymer The monomer unit contains 0.1% by mass to 0.8% by mass of the carboxyl group-containing monomer, preferably 0.1% by mass to 0.5% by mass, particularly preferably 0.1% by mass to 0.3% by mass. When the carboxyl group-containing monomer is in the above range, the obtained adhesive has excellent durability and deformation resistance. When the content of the carboxyl group-containing monomer is less than 0.1% by mass, the obtained adhesive has poor durability and deformation resistance. On the other hand, when the content of the carboxyl group-containing monomer is more than 0.8% by mass, when the attached adhesive is a transparent conductive film or the like, the transparent conductive film or the like is corroded, or the transparent conductive film is etched. A large change in the resistance value occurs.

The other monomer is preferably not contained in the isocyanate-based bridging agent (B), in order not to hinder the reaction of the hydroxyl group of the hydroxyl group-containing monomer and the carboxyl group of the carboxyl group-containing monomer with the isocyanate bridging agent (B). Reactive functional group monomer. Examples of such other monomers include (meth)acrylic acid alkoxyalkyl esters such as methoxyethyl (meth)acrylate and ethoxyethyl (meth)acrylate; acrylamide, A Non-branching acrylamide such as acrylamide; N,N-dimethylaminoethyl (meth)acrylate, N,N-dimethylaminopropyl (meth)acrylate, etc. A 3-grade amino (meth) acrylate; vinyl acetate, and the like. These may be used alone or in combination of two or more.

The polymerization method of the (meth) acrylate polymer (A) may be a random copolymer or a block copolymer.

The (meth) acrylate polymer (A) has a weight average molecular weight of from 1.4 to 2.5 million, preferably from 1.5 to 2.2 million, particularly preferably from 1.8 to 2,000,000. The weight average molecular weight in the present specification is a value in terms of polystyrene measured by a gel permeation chromatography (GPC) method.

When the weight average molecular weight of the (meth) acrylate polymer (A) is less than 1.4 million, the durability of the obtained adhesive is deteriorated. Further, when the weight average molecular weight of the (meth) acrylate polymer (A) exceeds 2.5 million, the deformation resistance of the obtained adhesive is lowered.

Further, in the adhesive composition P, the (meth) acrylate polymer (A) may be used alone or in combination of two or more. Further, the adhesive composition P may further contain a (meth) acrylate polymer which does not contain a hydroxyl group-containing monomer, an aromatic ring-containing monomer or a carboxyl group-containing monomer as a constituent monomer unit.

(2) Isocyanate bridging agent (B)

The isocyanate-based bridging agent (B) has an advantage of being excellent in reactivity with a hydroxyl group of the (meth)acrylate polymer (A) and reactivity with a mercapto group which the decane coupling agent (C) has.

The isocyanate-based bridging agent (B) is a bridging agent containing at least a polyisocyanate compound. Examples of the polyisocyanate compound include aromatic polyisocyanates such as methylphenyl diisocyanate, diphenylmethane diisocyanate, and xylene diisocyanate; aliphatic polyisocyanates such as hexamethylene diisocyanate; and isophorone; Examples of the alicyclic polyisocyanate such as a diisocyanate or a hydrogenated diphenylmethane diisocyanate, and the biuret or isocyanate thereof include ethylene glycol, propylene glycol, neopentyl glycol, trimethylolpropane and hydrazine. An additive such as sesame oil or the like which is a reactant containing a low molecular weight active hydrogen compound. In the case of being used for a polarizing plate, from the viewpoint of durability and workability, trimethylolpropane-modified aromatic polyisocyanate is preferred, and trimethylolpropane-modified methyl phenyl diisocyanate is particularly preferred. . The above isocyanate bridge The agent (B) may be used alone or in combination of two or more.

In the adhesive composition P, the content of the isocyanate-based bridging agent (B) is preferably 0.01 parts by mass to 1 part by mass, particularly preferably 0.05, based on 100 parts by mass of the (meth) acrylate polymer (A). The mass part is -0.5 parts by mass, and more preferably 0.1 parts by mass to 0.3 parts by mass. When the content of the isocyanate-based bridging agent (B) is in the above range, a bridging structure excellent in stress relaxation, durability, and deformation resistance can be formed in the obtained adhesive.

(3) decane coupling agent (C)

The decane coupling agent (C) in the present embodiment has a mercapto group. The thiol group reacts easily with the isocyanate group of the isocyanate-based bridging agent (B). As described above, it is presumed that the adhesive of the adhesive composition P is bridged, and the alkoxydecane of the decane coupling agent (C) is kept at a suitable distance from the (meth) acrylate polymer (A). That is, the plurality of isocyanate groups in the isocyanate-based bridging agent (B) are kept apart from each other and suspended from the (meth) acrylate polymer (A). In this way, the alkoxycarbane is present at a suitable distance from the (bridged) (meth) acrylate polymer (A), and an excellent coupling effect can be exerted, whereby the obtained adhesive is bonded. It is excellent in adhesion and excellent in adhesion durability even under high temperature conditions and hot and humid conditions. This effect is particularly remarkable when the attachment target of the adhesive is an inorganic material such as glass or metal.

The decane coupling agent (C) is an organic ruthenium compound having at least one fluorenyl group in the molecule and having at least one alkoxymethane, and has good compatibility with the binder component and has light permeability. For example, it is preferable to substantially For the transparent.

Examples of the above decane coupling agent (C) include 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, and 3-mercaptopropylpropyl group. a mercapto group-containing low molecular type decane coupling agent such as methyl dimethoxydecane; 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 3-mercaptopropylmethyldimethoxy a cocondensate of a decyl-containing decane compound such as a decane or the like, and an alkyl decane-containing compound such as methyltriethoxysilane, ethyltriethoxysilane, methyltrimethoxydecane or ethyltrimethoxydecane. A fluorenyl-containing oligomer-type decane coupling agent or the like. Among them, from the viewpoint of improving durability, a fluorenyl group-containing oligomer-type decane coupling agent is preferable, and a cocondensate containing a decyl decane compound and an alkyl decane-containing compound is particularly preferable, and 3-mercaptopropyl propyl group is further preferable. a cocondensate of oxydecane with methyltriethoxydecane. These may be used alone or in combination of two or more.

The content of the decane coupling agent (C) in the adhesive composition P is preferably 0.01 parts by mass to 0.4 parts by mass, particularly preferably 0.1% by mass based on 100 parts by mass of the (meth) acrylate polymer (A). Parts ~ 0.3 parts by mass. When the content of the decane coupling agent (C) is less than 0.01 parts by mass, it may be difficult to obtain an effect by the decane coupling agent (C). On the other hand, when the content of the decane coupling agent (C) exceeds 0.4 parts by mass, the reaction between the isocyanate-based bridging agent (B) and the (meth) acrylate polymer (A) may be inhibited.

(4) Various additives

The adhesive composition P may be added with various additives commonly used in acrylic adhesives, for example, a charge preventive agent, an adhesion-imparting agent, an oxidation preventive agent, an ultraviolet absorber, a light stabilizer, and a resist. Fuel, filler, refractive index modifier, etc.

Specific examples of the antistatic agent include N-butyl-4-methylpyridinium hexafluorophosphate and N-hexyl-4-methylpyridinium hexafluorophosphate. N-butyl-2-hexylpyridine perchlorate, bis(fluorosulfonimide) potassium (KFSI), bis(trifluoromethanesulfonimide) potassium (KTFSI), bis(fluorosulfonimide) Lithium (LIFSI), lithium bis(trifluoromethanesulfonium chloride) (LITFSI), N-butyl-2-hexylpyridinium bis(trifluoromethanesulfonyl)imide, and the like. These charge inhibitors may be used alone or in combination of two or more.

[Method for Producing Adhesive Composition]

The adhesive composition P can be obtained by producing a (meth) acrylate polymer (A), the obtained (meth) acrylate polymer (A), an isocyanate bridging agent (B), and a decane coupling agent ( C) Mixing is carried out while adding an additive as needed to manufacture.

The (meth) acrylate polymer (A) can be produced by polymerizing a mixture of monomer units constituting the polymer by a usual radical polymerization method. The polymerization of the (meth) acrylate polymer (A) can be carried out by a solution polymerization method or the like using a polymerization initiator as needed. Examples of the polymerization solvent include ethyl acetate, n-butyl acetate, isobutyl acetate, toluene, acetone, hexane, methyl ethyl ketone, and the like, and two or more kinds thereof may be used in combination.

Examples of the polymerization initiator include an azo compound and an organic peroxide, and two or more kinds thereof can be used at the same time. Examples of the azo compound include 2,2'-azobisisobutyronitrile, 2,2'-azobis(2-methylbutyronitrile), and 1,1'-azobis(cyclohexane-1). - nitrile), 2,2'-azobis(2,4-dimethylvaleronitrile), 2,2'-azobis(2,4-dimethyl-4-methoxyvaleronitrile), Dimethyl 2,2'-azobis(2-methylpropionate), 4,4'-azobis(4-cyanoshikimate), 2,2'-azobis(2-hydroxyl) Methylpropionitrile), 2,2'-azobis[2-(2-misoline-2-yl)propane], and the like.

Examples of the organic peroxide include benzamidine peroxide, t-butyl peroxybenzoate, cumene hydroperoxide, diisopropyl peroxydicarbonate, and di-n-propylperoxy. Dicarbonate, bis(2-ethoxyethyl)peroxydicarbonate, tert-butyl peroxy neopentate, tert-butyl peroxypivalate, (3,5,5-trimethyl Benzyl) peroxide, dipropylene peroxide, diethyl hydrazine peroxide, and the like.

Further, in the above polymerization step, the weight average molecular weight of the obtained polymer can be adjusted by mixing a chain shifting agent such as 2-mercaptoethanol.

After obtaining the (meth) acrylate polymer (A), an isocyanate bridging agent (B), a decane coupling agent (C), a diluent solvent, and the solution of the (meth) acrylate polymer (A) are added. The additive is added as needed, and sufficiently mixed to obtain a tackifying composition P (coating solution) diluted in a solvent.

As a diluent solvent for diluting the adhesive composition P to obtain a coating solution, for example, an aliphatic hydrocarbon such as hexane, heptane or cyclohexane; an aromatic hydrocarbon such as toluene or xylene; methylene chloride; Halogenated hydrocarbon such as dichloroethane; alcohol such as methanol, ethanol, propanol, butanol or 1-methoxy-2-propanol; acetone, methyl ethyl ketone, 2-pentanone, isophor Ketones such as ketone and cyclohexanone; esters such as ethyl acetate and butyl acetate; and cellosolve solvents such as ethyl cellosolve.

The concentration and viscosity of the coating solution to be prepared in this manner are not particularly limited as long as they are within the range of application, and may be appropriately selected depending on the case. For example, the concentration of the adhesive composition P can be diluted to 10% by mass to 40% by mass. In addition, when a coating solution is obtained, the addition of a diluent solvent or the like is not a requirement, and the adhesive composition P may be added without any addition as long as it is a coating viscosity. In this case, the adhesive composition P, (meth)acrylic acid The polymerization solvent of the ester polymer (A) is directly used as a coating solution of a diluent solvent.

[adhesive]

The adhesive according to the present embodiment is formed by bridging the adhesive composition P. The bridging of the adhesive composition P can be carried out by heat treatment. In addition, this heat treatment can also serve as a drying treatment for volatilizing a dilution solvent or the like of the adhesive composition P.

In the case of heat treatment, the heating temperature is preferably from 50 ° C to 150 ° C, particularly preferably from 70 ° C to 120 ° C. Further, the heating time is preferably from 30 seconds to 10 minutes, and particularly preferably from 50 seconds to 2 minutes. After the heat treatment, if necessary, a ripening period of about 1 to 2 weeks may be left at normal temperature (for example, 23 ° C, 50% RH). When the ripening period is required, when the ripening period is not required after the aging period, the adhesive layer is formed after the heat treatment is completed.

By the above heat treatment (and aging), a three-dimensional network structure is formed by bridging the isocyanate bridging agent (B) and the (meth) acrylate polymer (A). Further, the fluorenyl group of the decane coupling agent (C) is easily reacted with the isocyanate group of the isocyanate-based bridging agent (B), and it is presumed that the alkoxymethyl decane of the decane coupling agent (C) passes through the isocyanate-based bridging agent ( B), the (meth) acrylate polymer (A) is further provided at a suitable distance from the above structure, and exhibits an excellent coupling effect.

Further, the adhesive obtained by bridging the adhesive composition P has an appropriate aggregating power by containing an aromatic ring even when the three-dimensional network structure is in a loose state. Thereby, the stress relaxation property can be improved without lowering the cohesive force, and therefore the durability and deformation resistance of the adhesive are high. In addition, the excellent coupling effect by the decane coupling agent (C) is excellent in adhesion to a glass surface or the like, and exhibits excellent adhesion durability under high temperature conditions or under moist heat conditions. For example, when it is left to stand under high temperature conditions of 85 ° C or under hot humid conditions of 60 ° C and 90% RH for 250 hours, occurrence of floating, peeling, bubbles, and the like can be prevented and suppressed. In addition, when a thin polarizing plate and a film (for example, a film thickness of about 0.5 mm) bonded to the above-mentioned adhesive and a laminated body of a glass plate are left at a high temperature of 85 ° C for 250 hours, it is also possible to The bending of the laminate is suppressed to a small extent.

The gel fraction of the adhesive according to the present embodiment is preferably 55% to 80%, particularly preferably 60% to 75%. When the gel fraction is less than 55%, the cohesive force of the adhesive is insufficient, and durability and reworkability may be deteriorated. In particular, in the case of a COP polarizing plate, at the high temperature, sufficient adhesion durability may not be obtained. On the other hand, when the gel fraction exceeds 80%, the stress relaxation property is too low, and durability or deformation resistance may be lowered.

[bonding sheet]

As shown in Fig. 1, in the adhesive sheet 1A of the first embodiment, the release sheet 12, the adhesive layer 11 laminated on the release surface of the release sheet 12, and the adhesive layer are laminated in the order from the bottom to the top. The substrate 13 on the adhesive layer 11 is composed of a substrate 13 .

Further, as shown in Fig. 2, the adhesive sheet 1B according to the second embodiment is formed by the two peeling sheets 12a and 12b and the peeling surfaces of the two peeling sheets 12a and 12b. The adhesive layer 11 sandwiched between the release sheets 12a and 12b is formed. In addition, the peeling surface of the peeling sheet in this specification is the surface which has the peeling property in the peeling sheet, and the surface which carried out the peeling process, and the surface which shows the peeling-

In both of the adhesive sheets 1A and 1B, the adhesive layer 11 is composed of an adhesive formed by bridging the above-mentioned adhesive composition P.

The thickness of the adhesive layer 11 is appropriately determined depending on the purpose of use of the adhesive sheets 1A and 1B, but is usually in the range of 5 μm to 100 μm, preferably 10 μm to 60 μm. For example, when it is used as an optical member, particularly as an adhesive layer for a polarizing plate, it is preferably 10 μm to 50 μm, and particularly preferably 15 μm to 30 μm.

The base material 13 is not particularly limited, and any substrate used as a base material sheet of a usual adhesive sheet can be used. For example, in addition to desired optical members, woven or non-woven fabrics using rayon, acryl, and polyester; synthetic paper; paper of upper quality paper, cellophane, impregnated paper, copper paper, and the like; Metal foil such as aluminum or copper; foam of polyurethane foam, polyethylene foam, etc.; polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate Polyester film such as alcohol ester; cellulose film such as polyurethane film, polyethylene film, polypropylene film, cellulose triacetate; polyvinyl chloride film, polyvinylidene chloride film, polyvinyl alcohol film, ethylene-vinyl acetate A plastic film such as an ester copolymer film, a polystyrene film, a polycarbonate film, an acrylic resin film, a norbornene resin film, or a cycloolefin resin film; or a laminate of two or more of these. The plastic film may be a uniaxially rolled film or a biaxially rolled film.

Examples of the optical member include a polarizing plate (polarizing film), a polarizer, a retardation film (retardation film), a viewing angle compensation film, a brightness enhancement film, a contrast film, a liquid crystal polymer film, a diffusion film, and a semi-transmission. Reflective film, etc. Among them, the polarizing plate (polarizing film) is easy to shrink and the size changes. Since it is large, it is suitable as a base material which forms the adhesive agent (the said adhesive layer 11) of this embodiment from a viewpoint of durability. Further, in particular, a polycycloolefin film or a polarizing plate (COP polarizing plate) including the film is easily shrunk, has a large dimensional change, and has a large contact angle and low adhesion, so that adhesion and adhesion durability are required. From the viewpoint of the viewpoint, it is suitable as a base material for forming the adhesive (the above-mentioned adhesive layer 11) of the present embodiment.

The thickness of the base material 13 varies depending on the type thereof. For example, in the case of an optical member, it is usually 10 μm to 500 μm, preferably 50 μm to 300 μm, and particularly preferably 80 μm to 150 μm.

As the release sheets 12, 12a, 12b, for example, a polyethylene film, a polypropylene film, a polybutene film, a polybutadiene film, a polymethylpentene film, a polyvinyl chloride film, a vinyl chloride copolymer film, or a poly Ethylene terephthalate film, polyethylene naphthalate film, polybutylene terephthalate film, polyurethane film, vinyl acetate film, ionomer resin film, ethylene-(A) Acrylic copolymer film, ethylene-(meth)acrylate copolymer film, polystyrene film, polycarbonate film, polyimide film, fluororesin film, and the like. In addition, bridging films of these can also be used. Further, it is also possible to laminate these films.

It is preferable that the peeling surface of the peeling sheet (particularly the surface in contact with the adhesive layer 11) is subjected to a peeling treatment. Examples of the release agent used for the release treatment include a release agent of an alkyd, an anthrone, a fluorine, an unsaturated polyester, a polyolefin, and a wax.

The thickness of the release sheets 12, 12a, and 12b is not particularly limited, but is usually about 20 μm to 150 μm.

In the production of the above-mentioned adhesive sheet 1A, the solution (coating solution) containing the above-mentioned adhesive composition is applied and heat-treated on the release surface of the release sheet 12, and after the coating film is formed, the coating film is formed on the coating film. The substrate 13 is laminated. Further, when the coating film is not required to be matured, the adhesive layer 11 is directly formed, and when it is required to be matured, the adhesive layer 11 is formed after the ripening period. The heat treatment and the ripening conditions are as described above.

Further, in the production of the above-mentioned adhesive sheet 1B, the coating solution containing the above-mentioned adhesive composition is applied and heat-treated on the peeling surface of one of the release sheets 12a (or 12b), and after the coating film is formed, On the coating film, the peeling surface of the other release sheet 12b (or 12a) was polymerized. When the coating film is not required to be matured, it directly becomes the adhesive layer 11, and when it is required to be matured, it becomes the adhesive layer 11 after the ripening period.

As a method of applying the above coating solution, for example, a bar coating method, a knife coating method, a roll coating method, a plate coating method, a die coating method, a gravure coating method, or the like can be used.

The adhesive layer 11 in the adhesive sheets 1A and 1B has a haze value (value measured based on JIS K7136:2000) of preferably 1.0% or less, particularly preferably 0.9% or less, and further preferably 0.8% or less. When the haze value is 1.0% or less, the transparency is extremely high, and it is suitable for optical use.

Here, for example, in the liquid crystal display device including the liquid crystal module and the polarizing plate, a polarizing plate is used as the substrate 13 of the bonding sheet 1A, and the peeling sheet 12 of the bonding sheet 1A is peeled off to be exposed. The adhesive layer 11 and the liquid crystal module may be attached.

In addition, for example, manufacturing is configured between a liquid crystal module and a polarizing plate In the liquid crystal display device having the retardation plate, as an example, first, one of the release sheets 12a (or 12b) of the adhesive sheet 1B is peeled off, and the adhesive layer 11 and the phase difference plate exposed by the adhesive sheet 1B are bonded together. . Then, the release sheet 12 of the adhesive sheet 1A using the polarizing plate as the base material 13 is peeled off, and the adhesive layer 11 exposed by the adhesive sheet 1A and the phase difference plate are bonded together. Further, the other release sheet 12b (or 12a) is peeled off from the adhesive layer 11 of the above-mentioned adhesive sheet B, and the adhesive layer 11 from which the adhesive sheet B is exposed is bonded to the liquid crystal module.

According to the above-mentioned adhesive sheets 1A and 1B, since the adhesive layer 11 is excellent in durability, it is possible to prevent and suppress floating and peeling between the substrate 13 and the adherend even under high temperature conditions or under moist heat conditions. , bubbles, etc. In particular, when the COP polarizing plate is used as the base material 13, the stress which may be generated by the deformation of the COP polarizing plate can be absorbed and relaxed on the adhesive layer 11, thereby exhibiting excellent durability. Further, according to the above-mentioned adhesive sheets 1A and 1B, the adhesive layer 11 is excellent in deformation resistance, so that a thin polarizing plate and a film (for example, film thickness) which are bonded together by the adhesive layer 11 can be used even under high temperature conditions. The deformation of the laminate of the glass plate of about 0.5 mm is suppressed to be small.

In the adhesive sheets 1A and 1B of the present embodiment, it is also preferable to use a transparent conductive film as an adherend. The (meth) acrylate polymer (A) in the adhesive composition P, as a monomer unit, contains a small amount of the carboxyl group-containing monomer as described above, and thus can suppress the transparent conductive film due to the acid component. The negative impact. Specifically, it is possible to suppress the corrosion of the transparent conductive film or the resistance value of the transparent conductive film.

Examples of the transparent conductive film include metals such as platinum, gold, silver, and copper; tin oxide, indium oxide, cadmium oxide, zinc oxide, and dioxide. Oxide such as zinc; tin oxide indium tin oxide (ITO), indium oxide of zinc oxide, indium oxide of fluorine, tin oxide of antimony, tin oxide of fluorine, zinc oxide of aluminum, etc.; sulfide, six A transparent conductive film made of a non-oxidizing compound such as lanthanum boride, titanium nitride or titanium carbide.

Specifically, the change in the resistance value of the transparent conductive film will be specifically described. When the adhesive sheet 1A or the adhesive sheet 1B of the present embodiment is used, the adhesive layer 11 and the transparent conductive film are bonded together, and the obtained laminated body is When the wet heat promotion test for 500 hours of exposure is carried out in an atmosphere of 95° C. and 95% RH, the increase rate of the electric resistance value calculated by the following formula is preferably 15% or less, and particularly preferably 10% or less.

Resistance increase rate (%) = {(RR ₀ ) / R ₀ } × 100 (In the formula, R ₀ is the initial resistance value (Ω) before the damp heat promotion test, and R is the resistance value (Ω) after the damp heat promotion test .)

In addition, the details of the method for measuring the increase rate of the resistance value of the transparent conductive film will be described later.

The adhesive sheet 1A using a polarizing plate as the base material 13 (hereinafter referred to as "the adhesive layer polarizing plate is attached") is preferably 0.1 N/25 mm to 20 N with respect to the adhesive force of the flawless glass. /25 mm is particularly preferably 0.5 N/25 mm to 10 N/25 mm, and further preferably 1 N/25 mm to 5 N/25 mm. When the adhesive force is within the above range, it is possible to prevent floating, peeling, or the like from being adhered to the adherend such as a glass plate. In addition, the adhesive force referred to here basically means the adhesive force measured by the 180° peeling method based on JIS Z0237:2009, but the measurement sample is cut into a width of 25 mm and a length of 100 mm so that the measurement sample is viscous with respect to the adhesion. After being attached at 0.5 MPa, 50 ° C, and pressurized for 20 minutes, at normal pressure of 23 ° C, 50% RH After standing for 24 hours under the conditions, the adhesion obtained by the measurement was performed at a peeling speed of 300 mm/min.

The embodiments described above are described in order to facilitate understanding of the present invention, and are not intended to limit the present invention. Therefore, each of the elements disclosed in the above embodiments includes all design changes and equivalents belonging to the technical scope of the present invention.

For example, the release sheet 12 of the adhesive sheet 1A can be omitted, and any one of the release sheets 12a and 12b in the adhesive sheet 1B can be omitted.

[Examples]

The present invention will be specifically described by the following examples, but the scope of the present invention is not limited by the examples and the like.

[Example 1]

1. Modulation of (meth) acrylate polymer

76.9 parts by mass of n-butyl acrylate, 10 parts by mass of methyl acrylate, 10 parts by mass of 2-phenylethyl acrylate, 3 parts by mass of 2-hydroxyethyl acrylate, and 0.1 parts by mass of acrylic acid are copolymerized (A) Acrylate polymer (A). The molecular weight of the (meth) acrylate polymer (A) was measured by the method described later, and the weight average molecular weight was 1.5 million.

2. Modulation of adhesive composition

100 parts by mass of the (meth) acrylate polymer (A) obtained in the above step (1) (converted solid content; the same applies hereinafter); modified trimethylolpropane as an isocyanate bridging agent (B) 0.2 parts by mass of methyl phenyl diisocyanate (manufactured by Nippon Polyurethane Industry Co., Ltd., trade name "CORONATE L"); as a decane coupling agent (C) having a mercapto group, 3-mercaptopropyltrimethoxydecane and methyl three Ethoxygen The co-condensate of decane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-411-1810", thiol equivalent: 450 g/mol) 0.3 parts by mass, mixed well, and diluted with ethyl acetate to obtain a viscosity A coating solution of the conjugate composition.

Here, the matching of the adhesive composition is shown in Table 1. The details of the abbreviations and the like described in Table 1 are as follows.

[(Meth)acrylate polymer]

BA: n-butyl acrylate

MA: methyl acrylate

PhEA: 2-phenylethyl acrylate

HEA: 2-hydroxyethyl acrylate

AA: Acrylic

[decane coupling agent]

C1: a cocondensate of 3-mercaptopropyltrimethoxydecane and methyltriethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-411-1810")

C2: 3-glycidoxytrimethoxydecane (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "KBM-403")

3. Manufacture of adhesive layer with polarizer

The coating solution of the obtained adhesive composition was peeled off by the one side of the polyethylene terephthalate film by the ketone type release agent (The Linde Co., Ltd. product, The peel-treated surface of SP-PET3811, thickness: 38 μm was applied by a knife coater to a thickness of 25 μm after drying, and then heat-treated at 90 ° C for 1 minute to form a coating film of the adhesive composition.

Next, using a cellulose triacetate film to protect one side of the polarizer composed of the polyvinyl alcohol film, and protecting the other side with the cycloolefin polymer film The obtained COP polarizing plate having a thickness of 100 μm was bonded to the coating film, and the exposed surface of the coating film was brought into contact with the surface of the cycloolefin polymer film, and then allowed to stand at 23° C. and 50% RH for 7 days for aging. Thus, a polarizing plate with an adhesive layer was obtained.

[Examples 2 to 14, Comparative Examples 1 to 6]

The type and ratio of each monomer constituting the (meth) acrylate polymer (A), the weight average molecular weight of the (meth) acrylate polymer (A), and the amount of the isocyanate bridging agent (B), The type and amount of the decane coupling agent (C) were changed in the same manner as in Example 1 except that the type and amount of the decane coupling agent (C) were changed, and a polarizing plate with an adhesive layer was produced. Further, in Example 5, when the adhesive composition was prepared, 1.8 parts by mass of lithium bis(trifluoromethanesulfonium chloride) and tetraethylene glycol dimethyl ether were blended as a charge preventing agent. Moore mixed product (manufactured by Sanko Chemical Industry Co., Ltd., trade name "SANKONOL TGR").

Here, the above-mentioned weight average molecular weight (MW) is a polystyrene-equivalent weight average molecular weight measured by gel permeation chromatography (GPC) under the following conditions (GPC measurement).

<Measurement conditions>

‧GPC measuring device: manufactured by TOSOH, HLC-8020

‧GPC column (the following sequence is passed): TOSOH company

TSK guard column HXL-H

TSK gel GMHXL (×2)

TSK gel G2000HXL

‧ Determination of flux: tetrahydrofuran

‧Measurement temperature: 40 ° C

[Test Example 1] (Measurement of gel fraction)

In the examples or the comparative examples, instead of using the polarizing plate used for the polarizing plate with the adhesive layer, one side of the polyethylene terephthalate film was peeled off with an anthrone-based release agent. The treated release sheet (SP-PET3801, thickness: 38 μm, manufactured by Linde Co., Ltd.) was used to produce a bonded sheet. Specifically, the exposed coating film of the constituent film composed of the coating film of the release sheet/adhesive composition obtained in the production process of the example or the comparative example is placed so as to be in contact with each other on the side of the release-treated surface. The release sheet was laminated, and aging was carried out for 7 days under conditions of 23 ° C and 50% RH. Thus, an adhesive sheet formed of a release sheet (SP-PET3801)/adhesive layer (thickness: 25 μm)/release sheet (SP-PET3811) was prepared.

The obtained adhesive sheet was made into a sample of 80 mm × 80 mm size, and the adhesive layer was wrapped with a polyester mesh (mesh size 200), and only the quality of the adhesive was weighed with a precision balance. The mass at this time is taken as M1.

Next, the above-mentioned polyester net-wrapped adhesive was immersed in ethyl acetate at room temperature (23 ° C) for 24 hours. Thereafter, the adhesive was taken out, air-dried for 24 hours in an environment of a temperature of 23 ° C and a relative humidity of 50%, and further dried in an oven at 80 ° C for 12 hours. Only the quality of the dried adhesive is weighed with a precision balance. The mass at this time is taken as M2. The gel fraction (%) is represented by (M2/M1) × 100. The results are shown in Table 2.

[Test Example 2] (Measurement of haze value)

As the measurement sample, the same adhesive sheet as that used for the measurement of the gel fraction was prepared. For the adhesive layer (thickness: 25 μm) of the adhesive sheet, a haze meter (NDH2000, manufactured by Nippon Denshoku Industries Co., Ltd.) was used, based on JIS K7136:2000. The haze value (%) was measured. The results are shown in Table 2.

[Test Example 3] (Measurement of resistance increase rate)

The polarizing plate with the adhesive layer obtained in the examples or the comparative examples was measured for the electric resistance value of the ITO film according to the following test method, and the increase rate of the electric resistance value was calculated.

As shown in FIG. 3, a cross-sectional view of the sample S is measured for the resistance value. A polyethylene terephthalate (PET) film 21 having an ITO film 22 formed on one surface 21a was prepared by sputtering, and an adhesive tape 24 (manufactured by Linda Co., Ltd., trade name "TACKLINER TL-" was prepared. 70"), the surface 21b of the ITO film 22 on which the PET film 21 is not formed is bonded to the one surface 23a of the glass plate 23.

Then, a conductive resin material containing silver (manufactured by Fujikura Kasei Co., Ltd., trade name "FA-301CA" is formed on the reverse side (hereinafter referred to as "one surface") 22a of the surface of the ITO film 22 which is in contact with the PET film 21. The DOTITE touch panel circuit type has a rectangular electrode shape of 20 mm × 5 mm, and after coating, it is dried by heating at a temperature of 80 ° C for 20 minutes to form two electrodes 25 which are measurement points of resistance values. At this time, the positions of the two electrodes 25, 25 are adjusted so that the distance between them is slightly larger than 20 mm.

On the other hand, the polarizing plate 1A' with the adhesive layer obtained in the example or the comparative example was cut into a size of 20 mm × 250 mm, and the release sheet was peeled off (at this time, the polarizing plate with the adhesive layer was attached) 1A' is a laminate composed of the polarizing plate 13' and the adhesive layer 11. Thereafter, the adhesive layer 11 of the polarizing plate 1A' to which the adhesive is attached is adhered to the sides of the two electrodes 25, 25 (just not in contact therewith), and is attached to one surface 22a of the ITO film 22 A polarizing plate 1A' having an adhesive layer was used to prepare a sample S for measuring a resistance value as shown in FIG.

Then, as shown in FIG. 4, the initial resistance value R ₀ (Ω) between the electrodes 25 and 25 is measured by a digital altimeter (trade name "3802-50" manufactured by HIOKI.E Co., Ltd.) 30. Further, the sample for measuring the resistance value S was allowed to stand in an environment of 60° C. and 90% RH for 500 hours, and then the resistance value R (Ω) after the moist heat promotion was measured. Based on the obtained initial resistance value R ₀ and the resistance value R after the moist heat promotion, the resistance value increase rate of the resistance value measurement sample S was calculated by the following formula. The results are shown in Table 2.

Resistance increase rate (%) = {(RR ₀ ) / R ₀ } × 100

[Test Example 4] (Measurement of adhesion)

The polarizing plate with the adhesive layer obtained in the examples or the comparative examples was cut to prepare a sample having a width of 25 mm and a length of 100 mm. The peeling sheet was peeled off from the sample, and the sample was attached to the glass without the enamel glass (manufactured by Corning Co., Ltd., Eagle XG), and the pressure cooker manufactured by Kurihara Co., Ltd. was used at 0.5 MPa. Pressurize at 50 ° C for 20 minutes. Thereafter, the mixture was allowed to stand under normal pressure of 23 ° C and 50% RH for 24 hours, and then a tensile tester (TENSILON, manufactured by ORIENTEC Co., Ltd.) was used, and a peeling speed of 300 mm/min and a peeling angle of 180 were used based on JIS Z0237:2009. The condition of ° was measured for the adhesive force (adhesion force after 1 day of attachment; N/25 mm). The results are shown in Table 2.

[Test Example 5] (Durability evaluation)

The polarizing plate with the adhesive layer obtained in the examples or the comparative examples was cut to prepare a sample having a size of 200 mm × 150 mm. The release sheet was peeled off from the sample, and the exposed adhesive layer was attached to an aluminum-free glass (manufactured by Corning Co., Ltd., Eagle XG), and then a pressure cooker manufactured by Kurihara Co., Ltd. was used at 0.5 MPa and 50 ° C. Pressurize for 20 minutes.

After that, the product was placed in the following environment of durable conditions, and after 250 hours, the presence or absence of floating or peeling was confirmed by a magnifying glass of 10 times. The evaluation criteria are as follows. The results are shown in Table 2.

◎: No lifting or peeling was confirmed.

○: Float or peeling of a size of 0.5 mm or less was confirmed.

△: Float or peeling of a size of 0.5 mm or more and 1.0 mm or less was confirmed.

×: Float or peeling of a size of 1.0 mm or more was confirmed.

<endurance condition>

. 85°C dry

. 60 ° C, relative humidity 90% RH

[Test Example 6] (Evaluation of deformation resistance of panel)

The polarizing plate with the adhesive layer obtained in the examples and the comparative examples was cut to have a longitudinal direction of 200 mm and a lateral direction of 150 mm. The release sheet was peeled off from the polarizing plate with the adhesive layer, and the exposed adhesive layer was bonded to a flawless glass having a length of 250 mm, a lateral direction of 175 mm, and a thickness of 0.5 mm (manufactured by Corning Co., Ltd., trade name "Eagle- The central part of XG") is used as a sample. The sample was allowed to stand at 85 ° C in a dry atmosphere for 250 hours. Then, take it out in an environment of 25 ° C and 50% RH, place the polarizing plate side up, place it on the leveling table, and measure the amount of deformation (angle of the angle and the leveling table) of each corner (4) of the sample relative to the leveling table. , the total amount of deformation of each corner. The following evaluation was performed based on the results. The results are shown in Table 2.

◎: The total amount of deformation is 15mm or less

○: The total amount of deformation is 15 mm or more and 20 mm or less.

×: The total amount of deformation is 20 mm or more

[Test Example 7] (Evaluation of light leakage resistance)

The polarizing plate with the adhesive layer obtained in the example or the comparative example was adjusted to a size of 200 mm × 150 mm by a cutting device (SUPER CUTTER, PN1-600, manufactured by Takino Seisakusho Co., Ltd.). The peeling sheet was peeled off, and the exposed adhesive layer was attached to an aluminum-free glass (manufactured by Corning Co., Ltd., Eagle XG), and then pressed at a pressure of 0.5 MPa and 50 ° C for 20 minutes at 0.5 MPa and 50 ° C. . In addition, the above-mentioned bonding is performed on the inside and outside of the glassless glass, and the polarizing plate with the adhesive layer is applied under the condition that the polarization axis is in the cross-Nikkor state (polarization axis: ∠45°, ∠135°). After leaving it in this state for 80 hours in a dry environment of 80 ° C, it was allowed to stand in an environment of 23 ° C and 50% RH for 2 hours, and this was used as a sample, and the light leakage property was evaluated by the following method. The results are shown in Table 2.

<Evaluation method>

The above sample was placed on a FLAT ILLUMINATOR (manufactured by DENTSU SANGYO Co., Ltd., HF-SL-A312LC, illuminance: 26,000 Lux, luminance: 10,000 cd), and a two-dimensional color luminance meter (manufactured by Konica Minolta, CA-2000) was used. For the photography, the luminance distribution image was converted by an analysis software (CA-S20w, manufactured by Konica Minolta Co., Ltd.). The luminance distribution image of the obtained sample was evaluated based on the evaluation criteria shown in Fig. 5 and below.

◎: uniform brightness distribution

○: The brightness distribution of the four corners is slightly deformed

×: The brightness distribution of the four corners has a large deformation

[Test Example 8] (Measurement of surface resistance value of the adhesive layer)

The polarizing plate with the adhesive layer obtained in Example 5 was cut into a size of 50 mm × 50 mm, and the obtained sample was allowed to stand at a temperature of 23 ° C and a humidity of 50% RH for 24 hours. After that, the release sheet is peeled off, and the surface of the exposed adhesive layer is made of a resistor. The surface resistance value (Ω/Sq) was measured based on JIS K6911 by a rate meter (manufactured by Mitsubishi Chemical Corporation, HIRESTAUP MCP-HT450). The results are shown in Table 2.

Further, the surface resistance value is preferably 3.0 × 10 ¹¹ Ω / Sq or less, particularly preferably 1.0 × 10 ¹¹ Ω / Sq or less, and more preferably 8.0 × 10 ¹⁰ Ω / Sq or less. When the surface resistance value is at most the above value, good charge prevention property can be exhibited.

【Table 2】

As is clear from Table 2, the adhesive of the adhesive layer obtained in the examples was excellent in durability, deformation resistance, and light leakage resistance, and the resistance value of the adherend transparent conductive film was not easily changed.

[Industrial Availability]

The adhesive and the adhesive sheet of the present invention are suitable for a transparent conductive film, in particular, a transparent conductive film made of indium tin oxide (ITO) and an optical member, particularly a polarizing plate.

1A‧‧‧bonding strip

11‧‧‧Adhesive layer

12‧‧‧ peeling film

13‧‧‧Substrate

Claims (12)

An adhesive composition containing a weight average molecular weight of 1.4 million to 2.5 million as a monomer unit constituting a polymer, comprising a monomer having a hydroxyl group, a monomer having an aromatic ring, and a monomer having a carboxyl group (A) a acrylate polymer (A), an isocyanate bridging agent (B), and a decane coupling agent (C) having a mercapto group, and the above (meth) acrylate polymer (A) as a monomer constituting the polymer The unit contains 1% by mass to 5% by mass of the monomer having a hydroxyl group, 5% by mass to 30% by mass of the monomer having an aromatic ring, and 0.1% by mass to 0.8% by mass of the monomer having a carboxyl group. The adhesive composition according to claim 1, wherein the isocyanate-based bridging agent (B) is trimethylolpropane-modified methyl phenyl diisocyanate. The adhesive composition according to the first aspect of the invention, wherein the content of the isocyanate-based bridging agent (B) in the adhesive composition is polymerized with respect to the (meth) acrylate. The amount of the substance (A) is from 0.01 part by mass to 1 part by mass per 100 parts by mass. The adhesive composition according to claim 1, wherein the content of the decane coupling agent (C) in the adhesive composition is polymerized with respect to the (meth) acrylate. The amount of the substance (A) is from 0.01 part by mass to 0.4 part by mass per 100 parts by mass. The adhesive composition according to claim 1, wherein the monomer having an aromatic ring is 2-phenylethyl (meth)acrylate. An adhesive composition comprising the adhesive composition according to any one of claims 1 to 5. The adhesive according to claim 6, wherein the gel fraction is 55% to 80%. An adhesive sheet comprising: a substrate and an adhesive layer, wherein the adhesive layer is composed of the adhesive described in claim 6 of the patent application. The adhesive sheet according to claim 8, wherein the substrate is an optical member. The adhesive sheet according to claim 9, wherein the optical member is a polarizing plate. An adhesive sheet comprising two release sheets and an adhesive layer sandwiched by the release sheet in contact with a release surface of the two release sheets, wherein the adhesive layer is patented The adhesive composition of the sixth item is composed. The adhesive sheet according to claim 8, wherein the laminate of the adhesive layer and the transparent conductive film is subjected to a wet heat promotion test for 500 hours under an atmosphere of 65 ° C and 95% RH, The increase rate of the resistance value calculated by the transparent conductive film according to the following formula is 15% or less: the resistance value increase rate (%)={(RR ₀ )/R ₀ }×100, where R ₀ is the initial resistance value before the damp heat promotion test. , R is the resistance value after the moist heat promotion test.