KR20170032313A - Adhesive composition and adhesive using same, and adhesive for polarizing plate - Google Patents

Abstract

The pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (A) obtained by polymerizing a polymerization component containing a reactive functional group-containing monomer (a1), an acrylic resin (B) obtained by polymerizing a polymerization component not containing a reactive functional group- , The polymerization component of the acrylic resin (A) contains 2.5 to 30 wt% of the reactive functional group-containing monomer (a1), and the polymerization component of the acrylic resin (B) includes the non-reactive polar functional group-containing monomer .

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-sensitive adhesive composition, a pressure-sensitive adhesive composition using the same, and an adhesive for polarizing plate,

More particularly, the present invention relates to a pressure-sensitive adhesive composition for forming a pressure-sensitive adhesive excellent in durability, leak resistance, reworkability, transparency and antistatic property, and a pressure- And a pressure-sensitive adhesive for a polarizing plate.

Conventionally, both sides of a polyvinyl alcohol film or the like to which a polarizing property is imparted include a protective film (generally, a triacetyl cellulose film or a film that provides acrylic, cycloolefin, olefin, or a retardation layer) A polarizing plate coated with a triacetyl cellulose film is laminated on the surface of a liquid crystal cell in which a liquid crystal component oriented between two glass plates is sandwiched to form a liquid crystal display panel. Sensitive adhesive layer provided on the surface of the polarizing plate is pressed against the liquid crystal cell surface and pressed.

Such a polarizing plate typically has a three-layer structure in which both surfaces of a polyvinyl alcohol polarizer are sandwiched by a triacetylcellulose protective film. However, dimensional stability is insufficient due to the characteristics of these materials. In addition, since the polyvinyl alcohol polarizer is formed by stretching, the dimensional change due to heat and humidity in the environment tends to occur due to the heat of the backlight during the passage of time.

If the stress caused by the dimensional change can not be absorbed or relaxed, the distribution of the residual stress acting on the adhesive layer and the polarizing plate becomes uneven, and in particular, stress concentrates on the periphery of the polarizing plate. Thus, birefringence generated in each member, Or light leakage phenomenon occurs due to the pressure of the pressure-sensitive adhesive, or when the durability of the pressure-sensitive adhesive is low, the resulting stress causes peeling, peeling and foaming.

Therefore, as for the pressure sensitive adhesive for polarizing plate adhesion, it is preferable that the pressure-sensitive adhesive for polarizing plate is excellent in durability without causing foaming or peeling in a heat cycle from high temperature to high temperature under high temperature and high humidity, , Transparency, and so on.

As the pressure-sensitive adhesive for a polarizing plate developed for this purpose, for example,

(A), 100 to 500 parts by mass of an acrylic resin (B) having no functional group, a cross-linking agent (C), and a silane coupling agent (D)

The acrylic resin (A) is a copolymer of 100 parts by mass of the (meth) acrylic ester monomer (a) and 0.1 to 5 parts by mass of the monomer (c) having a functional group and having a weight average molecular weight of 1,000,000 to 2,500,000. B) is a polymer having a weight-average molecular weight of 1,000,000 to 2,500,000 and a (meth) acrylic ester monomer (b) containing no functional group-containing monomer. The monomer (a) and the monomer (b) Sensitive adhesive composition for a polarizing plate (see Patent Document 1), which is characterized in that it is at least 90 mass%

(Meth) acrylic copolymer having an alkyl group of 1 to 12 carbon atoms and having a gel fraction of 10 to 55% and an expansion ratio of 30 to 110, The acrylic pressure-sensitive adhesive composition for a polarizing plate (see Patent Document 2), wherein the sol has a weight average molecular weight of 800,000 or more and a molecular weight distribution of 2.0 to 7.0.

JP 2011-122104A JP 2009-507255 A

However, in recent years, with the enlargement of the image display apparatus and the reduction in the constitution of members, the polarizing plate constituting the image display apparatus is required to have a better balance of durability, leakage resistance, reworkability, transparency and antistatic property at a higher level In the techniques of the above Patent Documents 1 and 2, there is still room for improvement in durability. Particularly, durability is a test method under strict conditions, and durability performance in a heat cycle test suitable for practical use remains.

Therefore, in the present invention, under the circumstances, the present invention is a pressure-sensitive adhesive which exhibits excellent durability performance (in particular, resistance to heat cycle) when a polarizing plate and a glass substrate are adhered and also exhibits resistance to light leakage, reworkability, Compatibility, compatibility, compatibility) of a pressure-sensitive adhesive.

Therefore, the present inventors have conducted intensive studies in view of such circumstances, and as a result, they have found that a pressure-sensitive adhesive composition of the type that blends an acrylic resin (A) containing a reactive functional group and an acrylic resin (B) (A) containing a reactive functional group in an acrylic resin (B) containing a reactive functional group and containing a polar functional group in a non-reactive functional group-containing acrylic resin (B) (A) having a reactive functional group and an acrylic resin (B) having no reactive functional group can be obtained even when the pressure-sensitive adhesive composition of the present invention is used as a pressure- I have come to completion.

That is, the present invention includes the following forms (1) to (11).

(1) A pressure-sensitive adhesive composition comprising an acrylic resin (A) obtained by polymerizing a polymerization component containing a reactive functional group-containing monomer (a1), and an acrylic resin (B) obtained by polymerizing a polymerization component not containing a monomer having a reactive functional group, The polymerization component of the acrylic resin (A) contains 2.5 to 30% by weight of the reactive functional group-containing monomer (a1), and the polymerization component of the acrylic resin (B) includes the non-reactive polar functional group-containing monomer . ≪ / RTI >

(2) The pressure-sensitive adhesive composition according to (1), wherein the content of the non-reactive polar functional group-containing monomer (b1) in the polymerization component of the acrylic resin (B) is 0.1 to 30% by weight.

(3) The pressure-sensitive adhesive composition according to (1) or (2), wherein the reactive functional group-containing monomer (a1) is at least one member selected from the group consisting of a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

(4) The non-reactive polar functional group-containing monomer (b1) is at least one selected from the group consisting of an amide group-containing monomer, a tertiary amino group-containing monomer and an ether group- Sensitive adhesive composition according to any one of the preceding claims.

(5) The pressure-sensitive adhesive composition according to any one of (1) to (4), wherein the acrylic resin (A) has a weight average molecular weight of 1,000,000 or more.

(6) The pressure-sensitive adhesive composition according to any one of (1) to (5), wherein the acrylic resin (B) has a weight average molecular weight of 1,000,000 or more.

(7) The content ratio [(A) :( B)] (weight ratio) of the acrylic resin (A) and the acrylic resin (B) is (A) :( B) = 100: 50 to 100: Sensitive adhesive composition according to any one of (1) to (6) above.

(8) The pressure-sensitive adhesive composition according to any one of (1) to (7) above, which contains a crosslinking agent (C).

(9) The pressure-sensitive adhesive composition according to (8), wherein the crosslinking agent (C) is at least one selected from the group consisting of an isocyanate crosslinking agent and an epoxy crosslinking agent.

(10) The pressure-sensitive adhesive composition according to any one of (1) to (9) above, which is crosslinked by a crosslinking agent (C).

(11) A pressure-sensitive adhesive for a polarizing plate, which comprises the pressure-sensitive adhesive according to (10).

The pressure-sensitive adhesive obtained by using the pressure-sensitive adhesive composition of the present invention exhibits excellent durability (in particular, resistance to heat cycle) and is excellent in adhesion between an optical member such as a polarizing plate and a glass substrate. It is possible to obtain a liquid crystal display device free from foaming or peeling.

In addition, the above-mentioned pressure-sensitive adhesives are not only excellent in durability but also excellent in leak resistance and reworkability, and excellent in transparency because they are also excellent in compatibility between acrylic resins to be blended.

Hereinafter, the present invention will be described in detail.

Also, in the present invention, (meth) acryl means acryl or methacryl, (meth) acryloyl means acryloyl or methacryloyl, and (meth) acrylate means acrylate or methacrylate . The acrylic resin is a resin obtained by polymerizing a polymerization component containing at least one (meth) acrylate monomer.

In the present invention, the monomer is a polymerizable unsaturated group-containing compound, and the functional group contained in the monomer does not include such a polymerizable unsaturated group.

First, the acrylic resin (A) and the acrylic resin (B) contained in the pressure-sensitive adhesive composition of the present invention as an essential component will be described.

The acrylic resin (A) is obtained by polymerizing a polymerization component containing 2.5 to 30% by weight of the reactive functional group-containing monomer (a1). If necessary, the (meth) acrylic acid alkyl ester monomer (a2) or other copolymerizable ethylene The unsaturated monomer (a3) may be contained as a copolymerization component.

The reactive functional group in the above-mentioned reactive functional group-containing monomer (a1) is reacted with a crosslinking agent (C) to be described later under the general crosslinking reaction conditions (for example, , And the reactive functional group-containing monomer (a1) is a monomer containing a functional group which can be a crosslinking point when the acrylic resin (A) reacts with the crosslinking agent (C).

Specific examples of the reactive functional group-containing monomer (a1) include a hydroxyl group-containing monomer, a carboxyl group-containing monomer, an amino group-containing monomer, an acetoacetyl group-containing monomer, an isocyanate group-containing monomer and a glycidyl group- Among them, a hydroxyl group-containing monomer and a carboxyl group-containing monomer are preferable in that a crosslinking reaction can be efficiently carried out with various crosslinking agents.

Examples of the hydroxyl group-containing monomer include 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 5-hydroxypentyl (meth) acrylate, 6-hydroxyhexyl Acrylate, hydroxypropyl (meth) acrylate, and 8-hydroxyoctyl (meth) acrylate, caprolactone-modified monomers such as caprolactone-modified 2-hydroxyethyl (meth) , And polyethylene glycol (meth) acrylate, and other oxyalkylene-modified monomers such as 2-acryloyloxyethyl-2-hydroxyethylphthalic acid, N-methylol (meth) acrylamide, hydroxyethyl acrylamide Containing monomers such as 2-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate and 3-chloro-2-hydroxypropyl (meth) acrylate; 2,2-di Methyl-2-hydroxyethyl (meth) acrylate, and other tertiary hydroxyl group-containing monomers.

Among the hydroxyl group-containing monomers, monomers having a primary hydroxyl group are preferable from the viewpoint of excellent reactivity with a crosslinking agent, and monomers having a hydroxyl group at the molecular chain terminal are preferred because they easily exhibit excellent antistatic properties. Further, the use of 2-hydroxyethyl acrylate is particularly preferable from the viewpoint of easy production because of less impurities such as di (meth) acrylate.

As the hydroxyl group-containing monomer used in the present invention, it is also preferable to use a monomer having a content of di (meth) acrylate of 0.5% or less as an impurity and 0.2% or less, particularly 0.1% or less And specific examples thereof include 4-hydroxybutyl acrylate, 2-hydroxyethyl acrylate and 2-hydroxypropyl acrylate.

Examples of the carboxyl group-containing monomer include (meth) acrylic acid and acrylic acid, and include crotonic acid, maleic acid, maleic anhydride, fumaric acid, citraconic acid, glutaconic acid, itaconic acid, acrylamide N- Cinnamic acid, etc. Among them, (meth) acrylic acid is preferably used.

Examples of the acetacetyl group-containing monomer include 2- (acetacetoxy) ethyl (meth) acrylate, allylacetate, and the like.

Examples of the isocyanate group-containing monomer include 2-acryloyloxyethyl isocyanate, 2-methacryloyloxyethyl isocyanate and alkylene oxide adducts thereof.

Examples of the glycidyl group-containing monomer include glycidyl (meth) acrylate and allyl glycidyl (meth) acrylate.

These reactive functional group-containing monomers (a1) may be used alone or in combination of two or more. Among them, it is preferable to use a combination of a hydroxyl group-containing monomer and a carboxyl group-containing monomer in view of excellent reactivity with a crosslinking agent and storage stability.

When the hydroxyl group-containing monomer and the carboxyl group-containing monomer are used in combination, the content of the carboxyl group-containing monomer is preferably higher than that of the hydroxyl group-containing monomer, from the viewpoint of excellent durability.

The content of the reactive functional group-containing monomer (a1) is required to be 2.5 to 30% by weight, preferably 3 to 25% by weight, particularly preferably 3 to 20% by weight, Is 3.5 to 15% by weight.

When the content of the reactive functional group-containing monomer (a1) is too large, the reworkability is lowered or the stress relaxation property is lowered, and the leak resistance is deteriorated or the substrate is easily warped, while if too small, the durability is lowered.

As the (meth) acrylic acid alkyl ester monomer (a2), for example, the alkyl group usually has 1 to 20 carbon atoms, preferably 1 to 18 carbon atoms, particularly preferably 1 to 12 carbon atoms, more preferably 1 to 8 carbon atoms (Meth) acrylate, isobutyl (meth) acrylate, tert-butyl (meth) acrylate, isobutyl (meth) acrylate, n-hexyl (meth) acrylate, n-octyl (meth) acrylate, isodecyl Acrylate, cetyl (meth) acrylate, stearyl (meth) acrylate, and the like. These may be used alone, or two or more of them may be used in combination.

Of these, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable from the viewpoint of versatility and adhesive property, It is preferable to use a monomer as a main component.

The content of the (meth) acrylic acid alkyl ester monomer (a2) is preferably 40 to 97% by weight, particularly preferably 50 to 95% by weight, more preferably 60 to 95% by weight, to be.

If the content is too small, the resin tends to have a high price, but it tends to be difficult to balance the adhesive properties. If it is too large, the cohesive force tends to decrease or the leak resistance tends to decrease.

Examples of the other copolymerizable ethylenically unsaturated monomer (a3) include benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate, 2-hydroxy- Aromatic ring-containing monomers such as phenoxypropyl (meth) acrylate, orthophenylphenoxyethyl (meth) acrylate and the like;

(Meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclohexyloxyalkyl (Meth) acrylate, and isobornyl (meth) acrylate;

(Meth) acrylamides such as methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, propoxymethyl (meth) acrylamide, isopropoxymethyl (Meth) acrylamide monomers such as methyl (meth) acrylamide, (meth) acryloylmorpholine, dimethyl (meth) acrylamide, diethyl Amide-based monomers such as (meth) acrylamide-based monomers such as (meth) acrylamide;

(Meth) acrylate, 2-butoxyethyl (meth) acrylate, 2-ethoxyethyl (meth) acrylate, (Meth) acrylate, methoxyethyleneglycol (meth) acrylate, methoxyethyleneglycol (meth) acrylate, methoxytriethyleneglycol (meth) acrylate, ethoxydiethyleneglycol Containing (meth) acrylate such as glycidyl (meth) acrylate, octoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate and stearoxypolyethylene glycol mono Acrylic acid ester monomers;

Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl propionate, vinyl stearate, vinyl chloride, vinylidene chloride, alkyl vinyl ether, vinyl toluene, vinyl pyridine, vinyl pyrrolidone, itaconic acid dialkyl ester, , Allyl alcohol, acryl chloride, methyl vinyl ketone, N-acrylamidomethyltrimethylammonium chloride, allyltrimethylammonium chloride, dimethyl allyl vinyl ketone, and the like. These may be used alone or in combination of two or more.

Of these, aromatic ring-containing monomers are preferable, and benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol ( Containing monomer is preferable from the viewpoints of easy adjustment of refractive index and adjustment of birefringence and excellent adhesion to a low-polarity adherend (olefin base), and it is preferable to use an alicyclic monomer having excellent adhesiveness to a substrate and adherend, From the viewpoint of easy control of compatibility, amide-based monomers are preferred.

The content of the other copolymerizable ethylenically unsaturated monomer (a3) is preferably 0 to 50% by weight, more preferably 0 to 50% by weight, in the case of the aromatic ring-containing monomer (a3) Is 5 to 40% by weight, and more preferably 10 to 30% by weight. When the content is too large, it is difficult to control the birefringence and the light leakage suppressing effect tends to be lowered.

When the (a3) is other than the aromatic ring-containing monomer or the alicyclic monomer, it is preferably 0 to 10% by weight, particularly preferably 0 to 5% by weight, based on the total amount of the polymerization component. If the content is too large, the long-term storage stability of the acrylic resin (A) tends to be lowered or gelation tends to occur at the time of polymerization.

The acrylic resin (A) used in the present invention can be obtained by reacting the reactive functional group-containing monomer (a1), if necessary, with the (meth) acrylic acid alkyl ester-based monomer (a2) or other copolymerizable ethylenically unsaturated monomer By appropriately selecting and using a copolymerizable component. The above polymerization can be carried out by a conventionally known method such as solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization and the like.

For example, a polymerization component containing a reactive functional group-containing monomer (a1) and a polymerization initiator are mixed or dropped in an organic solvent to polymerize under predetermined polymerization conditions. Among these polymerization methods, solution radical polymerization and bulk polymerization are preferable, and solution radical polymerization is more preferable.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, esters such as ethyl acetate and butyl acetate, n-propyl alcohol, isopropyl alcohol and the like Aliphatic alcohols such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and the like.

Among these solvents, ethyl acetate, acetone, methyl ethyl ketone, butyl acetate, toluene and methyl isobutyl ketone are preferable from the standpoint of easiness of polymerization reaction, effect of chain transfer, ease of drying at the time of coating with a pressure-sensitive adhesive, Is ethyl acetate, acetone, and methyl ethyl ketone.

Examples of the polymerization initiator used for such radical polymerization include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2-methylbutyronitrile, Azo type initiators such as 4,4'-azobis (4-cyano valeric acid) and 2,2'-azobis (methyl propionic acid), benzoyl peroxide, lauroyl peroxide, di- Organic peroxides such as hydroperoxide, and the like, and they can be appropriately selected and used in accordance with the monomers to be used. These solvents may be used alone or in combination of two or more.

The lower limit of the weight average molecular weight of the acrylic resin (A) is preferably 600,000 or more, more preferably 800,000 or more, and still more preferably 1,000,000 or more. The upper limit of the weight average molecular weight of the acrylic resin (A) is preferably 2.5 million or less, more preferably 1.8 million or less, and even more preferably 1.6 million or less.

If the weight average molecular weight is too small, the durability tends to decrease. If the weight average molecular weight is too large, a large amount of diluting solvent is required at the time of production, and the dry composition tends to be lowered.

The dispersion degree (weight average molecular weight / number average molecular weight) of the acrylic resin (A) is preferably 30 or less, more preferably 15 or less, further preferably 7 or less, particularly preferably 5 or less.

When the degree of dispersion is too high, the cohesive force tends to be lowered. The lower limit of the degree of dispersion is 1.

The above weight average molecular weight is a weight average molecular weight in terms of standard polystyrene molecular weight, and the weight average molecular weight was measured by high performance liquid chromatography ("Waters 2695 (body)" and "Waters 2414 (detector)" manufactured by Nippon Waters Co., (GPC KF-806L (exclusion limit molecular weight: 2 x 10 ⁷ , separation range: 100 to 2 x 10 ⁷ , theoretical number of stages: 10,000 units / pack, filler material: styrene-divinylbenzene copolymer, Three series are used, and the number average molecular weight can be measured by the same method, with a sample concentration of about 1 mg / ml, a developing solvent: THF, and a flow rate of 1 ml / min. The degree of dispersion can be determined by weight average molecular weight and number average molecular weight.

The glass transition temperature (Tg) of the acrylic resin (A) is preferably -80 to 0 占 폚, more preferably -60 to -15 占 폚, and still more preferably -60 to -20 占 폚.

If the glass transition temperature is too high, the tackiness tends to decrease. If the glass transition temperature is too low, the heat resistance tends to decrease.

The glass transition temperature is calculated by the following Fox equation.

1 / Tg = w1 / Tg1 + w2 / Tg2 + ... Wk / Tgk

Wherein Tg is the glass transition temperature of the copolymer, Tg1, Tg2, ..., Tgk are the Tg of the individual copolymer of each monomer component, and w1, w2, Wk represents the weight fraction of each monomer component, and w1 + w2 + ... wk = 1.

The refractive index of the acrylic resin (A) is usually 1.440 to 1.600, preferably 1.440 to 1.550, and particularly preferably 1.440 to 1.500. It is preferable to reduce the difference between the refractive index and the refractive index of the member to be laminated because the light loss at the member interface becomes small.

The refractive index is a value obtained by measuring an acrylic resin with an NaD line using a refractive index measuring apparatus (" Abbe refractometer 1T "

The haze of the acrylic resin (A) is preferably 1.0% or less, more preferably 0.8% or less, particularly preferably 0.5% or less. If the haze is too high, the display quality tends to deteriorate. The lower limit of such a haze is usually 0.01%.

Thus, the acrylic resin (A) used in the invention is obtained.

The acrylic resin (B) is an acrylic resin (B) obtained by polymerizing a polymerization component not containing a monomer having a reactive functional group, and the polymerization component includes a monomer (b1) containing an unreactive polar functional group as an essential component, (Meth) acrylic acid alkyl ester-based monomer (b2) or other copolymerizable ethylenically unsaturated monomer (b3) may be contained as a copolymerization component.

The reactivity and the non-reactivity in the acrylic resin (B) are the same as the reactivity in the acrylic resin (A), under the general crosslinking reaction conditions for the crosslinking agent (C) described below (for example, (Lower than or equal to 60 ° C) (non-reactivity can be confirmed by the presence or absence of an increase in the gel fraction).

As the non-reactive polar functional group-containing monomer (b1), for example, when the crosslinking agent is an isocyanate group-containing crosslinking agent, it is preferably a monomer having an acetoacetoxy group, a monomer having a tertiary amino group (amino group containing no active hydrogen) Containing monomer, an epoxy group-containing monomer, and an ether group-containing monomer;

When the crosslinking agent is a carboxyl group-containing crosslinking agent, examples thereof include carboxyl group-containing monomers, hydroxyl group-containing monomers, amide group-containing monomers, amino group-containing monomers and ether group-containing monomers;

When the crosslinking agent is a crosslinking agent containing an acid anhydride structure, examples thereof include a carboxyl group-containing monomer, a carboxylic anhydride-containing monomer, and an acetacetoxy group-containing monomer;

When the crosslinking agent is a hydroxyl group-containing crosslinking agent, examples thereof include a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, an amide group-containing monomer, an amino group-containing monomer and an ether group-containing monomer;

When the cross-linking agent is a glycidyl group-containing cross-linking agent, the cross-linking agent may be a monomer having a tertiary amino group (an amino group containing no active hydrogen), an amide group-containing monomer, an ether group-containing monomer, an isocyanate group-containing monomer, Acetoxy group-containing monomers.

These non-reactive polar functional group-containing monomers (b1) may be used alone, or two or more kinds thereof may be used in combination.

Among these, (meth) acrylate-based monomers of each monomer are preferable, and specific examples thereof include (meth) acrylate containing an amide group, (meth) acrylate containing a tertiary amino group (amino group containing no active hydrogen) (Meth) acrylate is preferable, and an amide group-containing (meth) acrylate is particularly preferable from the viewpoint of excellent compatibility with the acrylic resin (A) and durability.

Examples of the amide group-containing (meth) acrylate include methoxymethyl (meth) acrylamide, ethoxymethyl (meth) acrylamide, propoxymethyl (meth) acrylamide, isopropoxymethyl (Meth) acrylamide monomers such as n-butoxymethyl (meth) acrylamide, n-butoxymethyl (meth) acrylamide and isobutoxymethyl (meth) acrylamide, (Meth) acrylamide-based monomers such as ethyl (meth) acrylamide and (meth) acrylamide N-methylol (meth) acrylamide.

Of these, dialkyl (meth) acrylamides are preferable from the standpoints of stability at the time of polymerization and stability at the time of storage, and particularly preferred are dimethyl acrylamide from the viewpoint of high molecular weight.

Examples of the tertiary amino group-containing (meth) acrylate include t-butylaminoethyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and diethylaminoethyl .

Examples of the ether group-containing (meth) acrylate include 2-methoxyethyl (meth) acrylate, 2- ethoxyethyl (meth) acrylate, 3- methoxybutyl (Meth) acrylate, methoxyethyleneglycol (meth) acrylate, methoxyethyleneglycol (meth) acrylate, methoxyethyleneglycol (Meth) acrylate, methoxypolyethylene glycol (meth) acrylate, octoxypolyethylene glycol polypropylene glycol mono (meth) acrylate, lauroxypolyethylene glycol mono (meth) acrylate, stearoxypolyethylene And ether-chain-containing (meth) acrylates such as glycol mono (meth) acrylate.

The content of the non-reactive polar functional group-containing monomer (b1) is preferably 0.1 to 30% by weight, particularly preferably 0.5 to 30% by weight, more preferably 1 to 25% by weight, Particularly preferably 3 to 25% by weight.

When the content of the non-reactive polar functional group-containing monomer (b1) is too large, there is a tendency that the resistance to moisture and humidity is lowered or the stability at the time of storage tends to deteriorate. When the content is too low, compatibility with the acrylic resin (A) .

Examples of the (meth) acrylic acid alkyl ester-based monomer (b2) include the same ones as the (meth) acrylic acid alkyl ester-based monomer (a2) described above. For example, the alkyl group preferably has 1 to 20 carbon atoms (Meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate, and the like. Acrylate, n-hexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isobutyl (meth) acrylate, (meth) acrylate, isooctyl (meth) acrylate, isooctyl (meth) acrylate, isodecyl (meth) acrylate, lauryl . These may be used alone, or two or more of them may be used in combination.

Of these, methyl (meth) acrylate, ethyl (meth) acrylate, n-butyl (meth) acrylate and 2-ethylhexyl (meth) acrylate are preferable from the viewpoint of versatility and adhesive property, It is preferable to make it the main component.

The content of the (meth) acrylic acid alkyl ester monomer (b2) is preferably 60 to 99.9% by weight, particularly preferably 70 to 99.5% by weight, more preferably 75 to 95% by weight, to be.

When the content is too small, the compatibility with the reactive functional group-containing acrylic resin (A) tends to be lowered, the resin price tends to increase, and if too large, the compatibility with the reactive functional group-containing acrylic resin (A) There is a tendency.

As the other copolymerizable ethylenically unsaturated monomer (b3), for example,

Aromatic ring-containing monomers such as benzyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxydiethylene glycol (meth) acrylate and orthophenylphenoxyethyl (meth) acrylate;

(Meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentanyl (meth) acrylate, cyclohexyl (meth) acrylate, cyclohexyloxyalkyl (Meth) acrylate, and isobornyl (meth) acrylate;

Acrylonitrile, methacrylonitrile, vinyl acetate, vinyl stearate, vinyl chloride, vinylidene chloride, vinyltoluene, vinylpyrrolidone, methylvinyl ketone, and dimethylallyl vinyl ketone. These may be used alone or in combination of two or more.

Of these, aromatic ring-containing monomers are preferable from the viewpoints of easy adjustment of refractive index and adjustment of birefringence, and particularly preferred are benzyl (meth) acrylate, phenoxy (meth) ethyl acrylate, phenoxy ethyleneglycol Acrylate, an alicyclic monomer is preferred from the viewpoints of easy adjustment of refractive index and adjustment of birefringence, and excellent adhesion to a low polarity adherend (cycloolefin).

The content of the other copolymerizable ethylenically unsaturated monomer (b3) is preferably 0 to 35% by weight in the case of the aromatic ring-containing monomer (b3) and the alicyclic monomer, Is 0 to 25% by weight, more preferably 0 to 15% by weight. If the content is too large, the glass transition temperature tends to be high, and the workability tends to decrease.

When the monomer (b3) is other than the aromatic ring-containing monomer or the alicyclic monomer, it is preferably 0 to 10% by weight, particularly preferably 0 to 5% by weight based on the total amount of the polymerization component. If the content is too large, the long-term storage stability of the acrylic resin (B) tends to deteriorate or the compatibility of the acrylic resin (A) and the acrylic resin (B) tends to be lowered.

The acrylic resin (B) used in the present invention can be obtained by copolymerizing the non-reactive polar functional group-containing monomer (b1), the (meth) acrylic acid alkyl ester-based monomer (b2) and other copolymerizable ethylenically unsaturated monomer By appropriately selecting, using and polymerizing the copolymerizable components contained in the copolymer. The polymerization may be carried out by a conventionally known method such as solution radical polymerization, suspension polymerization, bulk polymerization, emulsion polymerization and the like.

For example, a polymerization component containing a non-reactive polar functional group-containing monomer (b1) and a polymerization initiator are mixed or dropped in an organic solvent to polymerize under predetermined polymerization conditions. Among these polymerization methods, solution radical polymerization and bulk polymerization are preferable, and solution radical polymerization is more preferable.

Examples of the organic solvent used in the polymerization reaction include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as hexane, esters such as ethyl acetate and butyl acetate, n-propyl alcohol, isopropyl alcohol and the like Aliphatic alcohols such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; and the like.

Of these solvents, ethyl acetate, acetone, methyl ethyl ketone, butyl acetate, toluene and methyl isobutyl ketone are preferable from the standpoint of easiness of polymerization reaction, effect of chain transfer, ease of drying at the time of coating with a pressure-sensitive adhesive, Is ethyl acetate, acetone, and methyl ethyl ketone.

Examples of the polymerization initiator used for such radical polymerization include 2,2'-azobisisobutyronitrile, 2,2'-azobis-2-methylbutyronitrile, 2,2'-azobis-2-methylbutyronitrile, Azo type initiators such as 4,4'-azobis (4-cyano valeric acid) and 2,2'-azobis (methyl propionic acid), benzoyl peroxide, lauroyl peroxide, di- Organic peroxides such as hydroperoxide, and the like, and they can be appropriately selected and used in accordance with the monomers to be used. These solvents may be used alone or in combination of two or more.

The lower limit of the weight average molecular weight of the acrylic resin (B) is preferably 600,000 or more, more preferably 800,000 or more, and still more preferably 1,000,000 or more. The upper limit of the weight average molecular weight of the acrylic resin (B) is preferably 2.5 million or less, more preferably 1.8 million or less, and further preferably 1.6 million or less. If the weight average molecular weight is too small, the durability tends to decrease. If the weight average molecular weight is too large, a large amount of diluting solvent is required at the time of production, and the dry composition tends to be lowered.

The dispersion degree (weight average molecular weight / number average molecular weight) of the acrylic resin (B) is preferably 30 or less, more preferably 15 or less, further preferably 7 or less, particularly preferably 5 or less.

When the degree of dispersion is too high, the cohesive force tends to be lowered. The lower limit of the degree of dispersion is 1.

The method for measuring the weight average molecular weight is as described above.

The glass transition temperature (Tg) of the acrylic resin (B) is preferably -80 to 0 占 폚, more preferably -60 to -10 占 폚, and still more preferably -60 to -20 占 폚.

If the glass transition temperature is too high, the tackiness tends to decrease. If the glass transition temperature is too low, the heat resistance tends to decrease.

The method for measuring the glass transition temperature is as described above.

The refractive index of the acrylic resin (B) may be adjusted within a range of usually 1.440 to 1.600, preferably 1.440 to 1.550, and particularly preferably 1.440 to 1.500. It is preferable to reduce the difference between the refractive index and the refractive index of the member to be laminated because the light loss at the member interface becomes small. The method of measuring the refractive index is as described above.

The haze of the acrylic resin (B) is preferably 1.0% or less, more preferably 0.8 or less, and particularly preferably 0.5% or less.

If the haze is too high, the display quality tends to deteriorate. The lower limit of the haze is usually 0.01%.

Thus, the acrylic resin (B) used in the present invention is obtained.

The pressure-sensitive adhesive composition of the present invention contains the acrylic resin (A) and the acrylic resin (B) as essential constituents.

(A): (B) (weight ratio) of the acrylic resin (A) to the acrylic resin (B) is preferably 100: 50 to 100: 500, more preferably 100: (A): (B) = 100: 100 to 100: 400, and more preferably 100: 100 to 100: 350.

When the content ratio of the acrylic resin (B) to the acrylic resin (A) is too high, the degree of crosslinking tends to be low and the cohesive force tends to decrease. When the content is too small, the degree of crosslinking increases and the stress relaxation property tends to deteriorate.

The pressure-sensitive adhesive composition of the present invention preferably contains a crosslinking agent (C) and is crosslinked by the crosslinking agent (C) to become a pressure-sensitive adhesive.

Examples of the crosslinking agent (C) include an isocyanate crosslinking agent, an epoxy crosslinking agent, an aziridine crosslinking agent, a melamine crosslinking agent, an aldehyde crosslinking agent, an amine crosslinking agent and a metal chelating crosslinking agent. Among these, an isocyanate-based cross-linking agent and an epoxy-based cross-linking agent are preferable from the viewpoint of excellent durability and leak resistance.

Examples of the isocyanate crosslinking agent include 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, hydrogenated tolylene diisocyanate, 1,3-xylene diisocyanate, 1,4-xylene diisocyanate, (Isocyanatomethyl) cyclohexane, tetramethyl xylene diisocyanate, 1,5-naphthalene diisocyanate, triphenyl methane tri (meth) acrylate, isophorone diisocyanate, isophorone diisocyanate, Isocyanates, and adducts of these polyisocyanate compounds with polyol compounds such as trimethylolpropane, and biuret and isocyanurate compounds of these polyisocyanate compounds. Of these, adducts of 2,4-tolylene diisocyanate with trimethylol propane are particularly preferred because of their long pot life and excellent compatibility with resins.

Examples of the epoxy crosslinking agent include epoxy resins such as bisphenol A epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether , 1,6-hexanediol diglycidyl ether, trimethylol propane triglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol Polyglycidyl ether, and the like. Among them, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane, N, N, N'N'-tetraglycidyl-m-xylylenediamine desirable.

Examples of the aziridine crosslinking agent include tetramethylolmethane-tri-? -Aziridinylpropionate, trimethylolpropane-tri? -Aziridinylpropionate, N, N'-diphenylmethane- , 4'-bis (1-aziridine carboxamide), and N, N'-hexamethylene-1,6-bis (1-aziridine carboxamide).

Examples of the melamine-based cross-linking agent include hexamethoxymethylmelamine, hexaethoxymethylmelamine, hexapropoxymethylmelamine, hexaputoxymethylmelamine, hexapentyloxymethylmelamine, hexahexyloxymethylmelamine, melamine resin and the like. .

Examples of the aldehyde-based crosslinking agent include glyoxal, malondialdehyde, succinic aldehyde, maleindialdehyde, glutadialdehyde, formaldehyde, acetaldehyde, benzaldehyde and the like.

Examples of the amine-based crosslinking agent include hexamethylenediamine, triethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin and polyamide .

Examples of the metal chelate crosslinking agent include acetylacetone and acetoacetyl ester coordination compounds of a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, .

These crosslinking agents (C) may be used alone or in combination of two or more. It is preferable to use an isocyanate crosslinking agent and an epoxy crosslinking agent together from the viewpoint of durability.

The content of the crosslinking agent is preferably from 0.1 to 15 parts by weight, more preferably from 0.3 to 10 parts by weight, still more preferably from 0.5 to 10 parts by weight, particularly preferably from 0.5 to 10 parts by weight, based on 100 parts by weight of the acrylic resin (A) 1.0 to 7.5 parts by weight.

If the amount of the cross-linking agent is too small, the durability tends to deteriorate. If the amount is too large, the stress relaxation property tends to deteriorate or aging for a long time tends to be required.

The pressure-sensitive adhesive composition of the present invention preferably contains a silane coupling agent (D) from the viewpoint of improving the adhesion to the optical member. The antistatic agent (E) It is preferable from an excellent standpoint.

Examples of the silane coupling agent (D) include epoxy group-containing silane coupling agents, (meth) acryloyl group-containing silane coupling agents, mercapto group-containing silane coupling agents, hydroxyl group-containing silane coupling agents, An amino group-containing silane coupling agent, an amide group-containing silane coupling agent, and an isocyanate group-containing silane coupling agent. These may be used alone, or two or more of them may be used in combination. Among them, an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent are preferably used, and a combination of an epoxy group-containing silane coupling agent and a mercapto group-containing silane coupling agent can also be used to improve wet heat durability and adhesiveness .

The oligomer type silane compound, which is partially hydrolyzed and polycondensed, is also preferable from the viewpoint of excellent durability and reworkability.

Specific examples of the epoxy group-containing silane coupling agent include, for example,? -Glycidoxypropyltrimethoxysilane,? -Glycidoxypropyltriethoxysilane,? -Glycidoxypropylmethyldiethoxysilane,? -Glycidoxypropyltrimethoxysilane, (3,4-epoxycyclohexyl) ethyltrimethoxysilane,? - (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and the like can be used. Among them, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, β- (3,4-epoxycyclohexyl ) Ethyl trimethoxysilane.

Specific examples of the mercapto group-containing silane coupling agent include, for example,? -Mercaptopropyltrimethoxysilane,? -Mercaptopropyltriethoxysilane,? -Mercaptopropyldimethoxymethylsilane, SH group-containing silicon And alkoxy oligomers (mercapto group denaturated ethyl / methyl silicate low condensate).

The content of the silane coupling agent (D) is generally from 0.001 to 10 parts by weight, preferably from 0.01 to 1 part by weight, particularly preferably from 0.001 to 10 parts by weight, per 100 parts by weight of the total of the acrylic resin (A) and the acrylic resin (B) Is 0.02 to 0.5 parts by weight.

When the content of the silane coupling agent (D) is too small, the addition effect tends not to be obtained. When the content of the silane coupling agent (D) is too large, the adhesiveness of the pressure sensitive adhesive increases excessively, resulting in deterioration in reworkability or bleeding out of the pressure sensitive adhesive There is a tendency.

Examples of the antistatic agent (E) include cationic antistatic agents of quaternary ammonium salts such as imidazolium salt and tetraalkylammonium sulfonate, aliphatic sulfonate salts, higher alcohol sulfate ester salts, higher alcohol alkylene oxide adducts Anionic antistatic agents such as sulfuric acid ester salts, higher alcohol phosphoric acid ester salts and higher alcohol alcohol alkylene oxide adduct phosphoric acid ester salts, potassium bis (fluorosulfonyl) imide, lithium bis (trifluorosulfonyl) Alkali metal salts such as lithium, alkaline earth metal salts, higher alcohol alkylene oxide adducts, and polyalkylene glycol fatty acid esters.

The content of the antistatic agent (E) is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, and particularly preferably 0.5 to 5 parts by weight, per 100 parts by weight of the total of the acrylic resin (A) and the acrylic resin (B) 0.5 to 3 parts by weight.

When the content of the antistatic agent (E) is too small, the effect of addition tends to be not obtained. When the content of the antistatic agent (E) is too large, the surface tends to bleed on the surface of the pressure-

The pressure-sensitive adhesive composition of the present invention may contain other acrylic pressure-sensitive adhesives, other pressure-sensitive adhesives, urethane resins, rosin, rosin ester, hydrogenated rosin ester, phenol resin, aliphatic petroleum resin, Coloring agents, fillers, antioxidants, ultraviolet absorbers, and functional dyes, and compounds that cause coloration or discoloration by irradiation with ultraviolet rays or radiation can be compounded. In addition to the above additives, a small amount of impurities or the like contained in raw materials for the production of the constituent components of the pressure-sensitive adhesive composition may also be contained. These blending amounts can be appropriately set so as to obtain desired physical properties.

The pressure-sensitive adhesive composition of the present invention can be made into a pressure-sensitive adhesive by crosslinking (curing), and a pressure-sensitive adhesive layer-laminated optical member can be obtained by laminating a pressure-sensitive adhesive layer made of such a pressure-sensitive adhesive on an optical member (optical laminate) .

In the pressure-sensitive adhesive layer-laminated optical member, a release sheet is preferably provided on the surface opposite to the optical member surface of the pressure-sensitive adhesive layer.

As a method of producing the pressure-sensitive adhesive layer-laminated optical member, when the pressure-sensitive adhesive composition is cured by at least one of irradiation with active energy rays and heating, [1] a pressure- A method in which a sheet is attached and subjected to treatment with at least one of active energy ray irradiation and aging at room temperature or in a warm state; [2] a method in which a pressure-sensitive adhesive composition is applied and dried on a release sheet, [3] a method in which a pressure-sensitive adhesive composition is coated on an optical member, followed by drying, followed by irradiation with an active energy ray and aging at a room temperature or a warmed state; A method of applying a releasable sheet after performing at least one treatment, [4] a method of applying a pressure-sensitive adhesive composition onto a releasable sheet, drying the same, A method of attaching an optical member after performing treatment with an active energy ray and at least one of aging at a room temperature or a warm state, and the like.

Among them, aging at room temperature is preferred in view of the fact that the substrate is not damaged and the substrate adhesion is excellent.

Such aging treatment is carried out in order to balance the adhesive property as the reaction time of the chemical crosslinking of the pressure-sensitive adhesive. As the conditions for aging, the temperature is usually from room temperature to 70 DEG C and the time is usually from 1 day to 30 days. Specifically, For example, at 23 占 폚 for 1 day to 20 days, at 23 占 폚 for 3 days to 10 days, at 40 占 폚 for 1 day to 7 days, or the like.

When the pressure-sensitive adhesive composition is applied, it is preferable that the pressure-sensitive adhesive composition is diluted and applied to a solvent. The diluted concentration is preferably 5 to 60% by weight, more preferably 10 to 30% by weight as a heating residual concentration. The solvent is not particularly limited as long as it dissolves the pressure-sensitive adhesive composition, and examples thereof include ester solvents such as methyl acetate, ethyl acetate, methyl acetate and ethyl acetate, acetone, methyl ethyl ketone, methyl isobutyl ketone , Aromatic solvents such as toluene and xylene, and alcohol solvents such as methanol, ethanol and propyl alcohol. Of these, ester solvents, particularly ethyl acetate and ketone solvents, particularly methyl ethyl ketone, are preferably used from the viewpoints of solubility, dryness and cost.

The application of the pressure-sensitive adhesive composition is carried out by common methods such as roll coating, die coating, gravure coating, comma coating and screen printing.

The gel fraction of the pressure-sensitive adhesive layer produced by the above method is preferably from 30 to 95%, particularly preferably from 40 to 85%, more preferably from 45 to 80%, from the viewpoints of endurance performance and light leakage- %to be. If the gel fraction is too low, the durability due to lack of cohesive strength tends to become insufficient. In addition, if the gel fraction is too high, the tackiness tends to be caused by the increase of the cohesive force, and the tackiness or peeling tends to occur easily.

The gel fraction measured by the above measurement is preferably higher than the ratio of the weight of the acrylic resin (A) and the cross-linking agent (C) in the pressure-sensitive adhesive to the total weight of the pressure-sensitive adhesive, %. If it is too low, durability tends to be lowered.

The pressure-sensitive adhesive layer produced by the above method is preferable because the pressure-sensitive adhesive layer having a favorable tactile feel when touched with a finger tends to increase workability because of its good wettability when adhered to an adherend.

When adjusting the gel fraction of the pressure sensitive adhesive for an optical member to the above range, for example, adjusting the amount or type of crosslinking agent, adjusting the blending ratio of the acrylic resin (A) and the acrylic resin (B) Adjusting the amount and kind of the functional group of the acrylic resin (A), and adjusting the molecular weight of the acrylic resin (A) or the acrylic resin (B).

The gel fraction is a standard for the degree of crosslinking (degree of curing) and is calculated, for example, by the following method. That is, about 0.1 g of the pressure-sensitive adhesive layer was cut out from the pressure-sensitive adhesive sheet (without the separator) having the pressure-sensitive adhesive layer formed on the polarizing plate serving as the base and the pressure-sensitive adhesive layer was wrapped in a 200 mesh SUS wire net, Immersed for 24 hours, and the weight percentage of the insoluble adhesive component remaining in the wire net is taken as the gel fraction.

The thickness of the pressure-sensitive adhesive layer in the obtained pressure-sensitive adhesive layer-laminated optical member is preferably 5 to 300 占 퐉, more preferably 10 to 50 占 퐉, and further preferably 10 to 30 占 퐉. If the thickness of the pressure-sensitive adhesive layer is too thin, the adhesive property tends to become unstable. If it is too thick, the reworkability tends to decrease or the thickness of the entire optical member tends to increase excessively.

In the pressure-sensitive adhesive layer-laminated optical member of the present invention, a release sheet is peeled off directly or with a release sheet, and then the pressure-sensitive adhesive layer surface is bonded to a glass substrate and provided, for example, on a liquid crystal display panel.

The initial adhesive force of the pressure-sensitive adhesive layer of the present invention is appropriately determined depending on the material of the adherend or the like. For example, when it is attached to a glass substrate, it is preferable to have an adhesive force of 0.2 N / 25 mm to 15 N / 25 mm, more preferably 0.5 N / 25 mm to 10 N / 25 mm, 25 mm to 10 N / 25 mm.

The initial adhesive force is calculated as follows. The pressure-sensitive adhesive layer laminated polarizing plate was cut to a width of 25 mm, the releasing film was peeled off, and the pressure-sensitive adhesive layer side was pressed against a non-alkali glass plate ("Eagle XG" manufactured by Corning Incorporated) to attach a polarizing plate and a glass plate. Thereafter, the substrate was subjected to an autoclave treatment (50 DEG C, 0.5 MPa, 20 minutes), followed by standing at 23 DEG C and 50% RH for 24 hours, and then subjected to a 180 DEG C peeling test.

The optical member in the present invention is not particularly limited and may be an optical film that is suitably used in an image display apparatus such as a liquid crystal display apparatus, an organic EL display apparatus, or a PDP, for example, a polarizing plate or a retardation plate, An optical compensation film, a luminance enhancement film, and a laminate thereof. Among them, a polarizing plate is particularly effective in the present invention.

The polarizing plate used in the present invention is usually a laminated film of triacetylcellulose (TAC) -based films on both sides of a polarizing film, and the polarizing film preferably has an average degree of polymerization of 1,500 to 10,000 and a saponification degree of 85 to 100 moles % Of a polyvinyl alcohol resin is used as a raw film in an aqueous solution of iodine-potassium iodide or a monoaxially stretched film dyed with a dichroic dye (usually, stretched 2 to 10 times, preferably 3 to 7 times, Magnification) is used.

The polyvinyl alcohol-based resin is usually produced by saponifying polyvinyl acetate polymerized with vinyl acetate, but it is preferable to use a small amount of unsaturated carboxylic acid (including salts, esters, amides, nitriles and the like), olefins, vinyl ethers, A sulfonic acid salt, or the like, or a copolymerizable component with vinyl acetate. Also included are so-called polyvinyl acetal resins and polyvinyl alcohol derivatives such as polybutyral resins and polyvinyl formal resins obtained by reacting polyvinyl alcohol with aldehydes in the presence of an acid.

In addition to the triacetylcellulose film commonly used as a protective film for the polarizing plate, an acrylic film, a polyethylene film, a polypropylene film, a cycloolefin film and the like can be given.

It is also possible to use a protective film polarizer in which the protective film on the side of attaching to the optical member is removed for thinning.

(Example)

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to the following Examples unless the gist thereof is exceeded. In the examples, " part " and "% "

First, various acrylic resins were prepared as follows. The measurement of the weight-average molecular weight, the degree of dispersion, the glass transition temperature and the refractive index of the acrylic resin (A) and the acrylic resin (B) was carried out according to the above-mentioned method.

The measurement of the viscosity was carried out in accordance with 4.5.3 rotational viscometer method of JIS K 5400 (1990).

[Preparation of acrylic resin (A)]

≪ Production of acrylic resin (A-1) >

86.5 parts of butyl acrylate (BA) (a2), 10 parts of benzyl acrylate (BzA) (a3), 2 parts of 2-heptyl acrylate (a3) 0.5 part of hydroxyethyl acrylate (HEA) (a1), 3 parts of acrylic acid (AAc) (a1), 47.2 parts of ethyl acetate, 42 parts of acetone and 0.013 part of azobisisobutyronitrile (AIBN) (A-1) solution (weight average molecular weight: 1.5 million, dispersion degree: 3.1, glass transition temperature: -48 ° C, solid content concentration: 19.5%) was diluted with ethyl acetate while reacting with AIBN and ethyl acetate at a reflux temperature for 3.25 hours. , A viscosity of 4580 mPa 占 퐏 (25 占 폚), and a refractive index of 1.477).

≪ Preparation of acrylic resin (A-2) >

(A2), 10 parts of benzyl acrylate (a3), 2 parts of a 2-hydroxyethyl acrylate (a1), 2 parts of a propylene glycol monomethyl ether ), 0.5 parts of acrylic acid (a1), 5 parts of ethyl acetate, 47.2 parts of acetone, 42 parts of acetone and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate (Having a weight average molecular weight of 1,500,000, a dispersion degree of 3.3, a glass transition temperature of -46 占 폚, a solid content concentration of 19.9%, a viscosity of 5640 mPa 占 퐏 (25 占 폚) and a refractive index of 1.478) by diluting with ethyl acetate, ≪ / RTI >

≪ Preparation of acrylic resin (A-3) >

82 parts of butyl acrylate (a2), 10 parts of benzyl acrylate (a3), 2 parts of 2-hydroxyethyl acrylate (a1), and 2 parts of anhydrous ethyl acrylate were added to a bottomed round flask equipped with four openings equipped with a reflux condenser, stirrer, nitrogen gas inlet, ), 0.5 parts of acrylic acid (a1), 7.5 parts of ethyl acetate, 47.2 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate (Having a weight average molecular weight of 1,400,000, a dispersion degree of 3.6, a glass transition temperature of -43 占 폚, a solid content concentration of 19.9%, a viscosity of 6380 mPa 占 퐏 (25 占 폚) and a refractive index of 1.479) by diluting with ethyl acetate, .

≪ Preparation of acrylic resin (A-4) >

84.4 parts of butyl acrylate (a2), 10 parts of benzyl acrylate (a3), 2 parts of 2-hydroxyethyl acrylate (a1) were added to a four-neck round bottom flask equipped with a reflux condenser, stirrer, nitrogen gas inlet, ), 0.6 parts of acrylic acid (a1), 5 parts of ethyl acetate, 47.2 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and the mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate (Having a weight average molecular weight of 1,500,000, a dispersion degree of 3.8, a glass transition temperature of -46 占 폚, a solid content concentration of 19.9%, a viscosity of 6380 mPa 占 퐏 (25 占 폚) and a refractive index of 1.478) by diluting with ethyl acetate, ≪ / RTI >

≪ Preparation of acrylic resin (A-5) >

(A2), 10 parts of benzyl acrylate (a3), 2 parts of a 2-hydroxyethyl acrylate (a1), 2 parts of a propylene glycol monomethyl ether ), 0.5 parts of acrylic acid (a1), 47.2 parts of ethyl acetate, 42 parts of acetone and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and the mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate (A weight average molecular weight of 1.4 million, a dispersion degree of 3.0, a glass transition temperature of -49 占 폚, a solid content concentration of 20.6%, a viscosity of 7500 mPa 占 퐏 at 25 占 폚 and a refractive index of 1.477) by diluting with ethyl acetate, ≪ / RTI >

≪ Preparation of acrylic resin (A-6) >

62.4 parts of butyl acrylate (a2), 30 parts of benzyl acrylate (a3), 2 parts of 2-hydroxyethyl acrylate (a1, (AIBN) and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added to the reaction system and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate. The resulting solution was diluted with ethyl acetate to obtain a solution of an acrylic resin (A-6) having a weight average molecular weight of 1,400,000, a dispersion degree of 4.2, a glass transition temperature of -33 占 폚, a solid content concentration of 22.6%, a viscosity of 8700 mPa 占 퐏 at 25 占 폚, ).

≪ Preparation of acrylic resin (A'-1)

88 parts of butyl acrylate (a2), 10 parts of benzyl acrylate (a3), 2 parts of 2-hydroxyethyl acrylate (a1), and 2 parts of anhydrous ethyl acrylate were added to a four-neck round bottom flask equipped with a reflux condenser, stirrer, nitrogen gas inlet, ), 0.5 part of acrylic acid (a1), 1.5 parts of ethyl acetate, 47.2 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate And then diluted with ethyl acetate to obtain an acrylic resin (A'-1) solution having a weight average molecular weight of 1.4 million, a degree of dispersion of 3.5, a glass transition temperature of -49 占 폚, a solid content concentration of 19.8%, a viscosity of 4780 mPa 占 퐏 1.476).

[Preparation of acrylic resin (B)]

≪ Acrylic resin (B-1) >

93 parts of butyl acrylate (bA) (b2), 2 parts of methyl methacrylate (MMA) (b2), 0.1 part of dimethyl (meth) acrylate, 5 parts of acrylamide (DMAA) (b1), 43 parts of ethyl acetate, 42 parts of acetone and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate (Having a weight average molecular weight of 110,000, a dispersion degree of 4.6, a glass transition temperature of -49 占 폚, a solid content concentration of 22.1%, a viscosity of 3800 mPa 占 퐏 (25 占 폚) and a refractive index of 1.469) by diluting with ethyl acetate, .

≪ Acrylic resin (B-2) >

90.5 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 7.5 parts of dimethyl acrylamide (b1) 7.5 parts, and the mixture was charged into a four-neck round bottom flask equipped with a stirrer, a reflux condenser, , 43 parts of ethyl acetate, 42 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added. The mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate, diluted with ethyl acetate, A glass transition temperature of -47 占 폚, a solid content concentration of 22.5%, a viscosity of 4900 mPa 占 퐏 (25 占 폚), and a refractive index of 1.470.

≪ Acrylic resin (B-3) >

88 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 10 parts of dimethylacrylamide (b1) 10 (trade name, manufactured by Mitsubishi Chemical Corporation) were added to a bottomed round flask equipped with four openings equipped with a stirrer, a reflux condenser, , 43 parts of ethyl acetate, 42 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate. After diluting with ethyl acetate, (Weight average molecular weight: 1.3 million, dispersion degree: 4.0, glass transition temperature: -44 占 폚, solid content concentration: 22.4%, viscosity: 4800 mPa 占 퐏 (25 占 폚), refractive index: 1.472).

≪ Acrylic resin (B-4) >

83 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 15 parts of dimethylacrylamide (b1) 15, and a mixture of methyl acrylate (b1) , 43 parts of ethyl acetate, 42 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added. The mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate, diluted with ethyl acetate, (A weight average molecular weight of 1.3 million, a dispersion degree of 4.3, a glass transition temperature of -38 占 폚, a solid content concentration of 23.4%, a viscosity of 7900 mPa 占 퐏 (25 占 폚), and a refractive index of 1.475).

≪ Acrylic resin (B-5) >

78 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 20 parts of dimethylacrylamide (b1) 20, 2 parts of methyl acrylate (b1) were added to a bottomed round flask equipped with four openings equipped with a stirrer, a nitrogen gas inlet, , 43 parts of ethyl acetate, 42 parts of acetone, and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added. The mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate, diluted with ethyl acetate, (Having a weight average molecular weight of 1,400,000, a dispersion degree of 3.6, a glass transition temperature of -33 占 폚, a solid content concentration of 22.2%, a viscosity of 4500 mPa 占 퐏 (25 占 폚), and a refractive index of 1.478).

≪ Acrylic resin (B-6) >

93 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 5 parts of dimethylacrylamide (b1) 5, and 5 parts of dimethyl acrylamide were charged in a bottomed round flask equipped with four openings equipped with a stirrer, a nitrogen gas inlet, , 22 parts of ethyl acetate, 42 parts of acetone and 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added, and the mixture was reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate. After diluting with ethyl acetate, (Weight average molecular weight: 1.3 million, dispersion degree: 2.9, glass transition temperature: -49 占 폚, solid content concentration: 22.7%, viscosity: 8200 mPa 占 퐏 (25 占 폚), refractive index: 1.469).

≪ Acrylic resin (B'-1) >

98 parts of butyl acrylate (b2), 2 parts of methyl methacrylate (b2), 43 parts of ethyl acetate, and 50 parts of acetone 42 (trade name) in a four-necked round bottom flask equipped with a stirrer, a nitrogen gas inlet, And 0.013 part of azobisisobutyronitrile (AIBN) as a polymerization initiator were added to the reaction mixture and reacted at reflux temperature for 3.25 hours while appropriately adding AIBN and ethyl acetate and diluted with ethyl acetate to obtain an acrylic resin (B'-1) solution A glass transition temperature of -54 占 폚, a solid content concentration of 22.0%, a viscosity of 4300 mPa 占 퐏 (25 占 폚), and a refractive index of 1.466).

[Examples 1 to 16 and Comparative Examples 1 to 9]

<Compatibility (Transparency)>

The acrylic resin (A) and the acrylic resin (B) were blended at a weight ratio (solid content ratio) of 1: 1 in the combinations described in Table 3, (Toraylum Mirror SP01): The coating was applied to a thickness of 38 탆. After drying at 100 캜 for 3 minutes, the coating was applied to a non-alkali glass ("Eagle XG", manufactured by Corning Incorporated, thickness 1.1 mm) (Transparency) was evaluated by measuring the haze (%) using a meter "HAZE MATER NDH2000" (manufactured by Nippon Denshoku Kogyo Co., Ltd.), and this apparatus was in conformity with JIS K 7361-1. The results are shown in Table 3. &lt; tb &gt; &lt; TABLE &gt;

(evaluation)

○ · · · Less than 1% haze

× ... Haze is 1% or more

[Crosslinking agent (C)]

The following crosslinking agent (C) was prepared.

(C-1): A 55% ethyl acetate solution of a tolylene diisocyanate adduct of trimethylolpropane ("Colonate L-55 E" manufactured by Nippon Polyurethane Industry Co., Ltd.)

(C-2) 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane ("TETRAD C" manufactured by Mitsubishi Gas Kagaku Co.,

[Silane coupling agent (D)]

The following silane compound (D) was prepared.

(D-1): oligomer type silane compound ("X41-1805" manufactured by Shin-Etsu Chemical Co., Ltd.) (D-2)

3-glycidoxypropyltrimethoxysilane (KBM-403 manufactured by Shin-Etsu Chemical Co., Ltd.)

[Antistatic Agent (E)]

The following antistatic agent (E) was prepared.

(E-1): Lithium bistrifluoromethanesulfonylimide (tetraethylene glycol dimethyl ether dispersion) ("Sankonol TGR" manufactured by Sanko Chemical Industry Co., Ltd.)

(E-2): Tri-n-butylmethylammonium bistrifluoromethanesulfonimide ("FC-4400" manufactured by Suri M Co.,

[Examples 17 to 30, Comparative Examples 10 to 15]

The pressure-sensitive adhesive composition to be a pressure-sensitive adhesive-forming material was prepared by blending the components prepared and prepared as described above in the ratios shown in Table 4 below. The pressure-sensitive adhesive composition was diluted with ethyl acetate (viscosity [500 to 10,000 mPa · s )) To prepare a pressure-sensitive adhesive composition solution.

Subsequently, the pressure-sensitive adhesive composition solutions of Examples 17 to 30 and Comparative Examples 10 to 15 were applied to a polyester release sheet so that the thickness after drying was 25 탆 and dried at 100 캜 for 3 minutes, (Protective film: TAC film manufactured by Fuji Photo Film Co., Ltd.) and aged for 7 days under conditions of 23 캜 and 65% RH to obtain a pressure-sensitive adhesive layer laminated polarizing plate.

Further, the polarizing plate was cut so as to be at 0 degree with respect to the stretching axis.

The pressure-sensitive adhesive layer laminated polarizing plate thus obtained was used to evaluate the gel fraction, durability (anti-moisture heat resistance test, heat resistance test, heat cycle test), resistance to light leakage, adhesive force and reworkability, retention force, antistatic performance, The measurement and evaluation were conducted according to each method. These results are shown together in Table 4 below.

[Gel fraction]

The release sheet of the obtained pressure-sensitive adhesive layer laminated polarizing plate was peeled off and the pressure-sensitive adhesive layer was cut off by 0.1 g. The pressure-sensitive adhesive layer was covered with a 200 mesh SUS wire net and immersed in ethyl acetate at 23 占 폚 for 24 hours to remove the insoluble adhesive The weight percentage of the component was determined.

[Durability, Leak Resistance]

The obtained release sheet of the pressure-sensitive adhesive layer polarizing plate was peeled off and the pressure-sensitive adhesive layer side was pressed against an alkali-free glass plate (Eagle XG, manufactured by Corning Incorporated), and the polarizing plate and the glass plate were attached, followed by autoclave treatment (50 ° C, 0.5 MPa, 20 Minute). Thereafter, foaming and peeling were evaluated in the durability test (anti-wet heat resistance test, heat resistance test, and heat cycle test) as described below.

In addition, in the heat resistance test, in addition to the evaluation of the foaming and the like, a sample for observing light leakage was prepared by attaching the same sample to both the table and the back surface so that the polarizing plate was crossed nicols (stretching axis is 0-90 degrees) The same was also evaluated for leaking light resistance. The size of the test piece used was 20 cm x 15 cm. However, in the light leakage test of Example 30, 31 cm × 17.4 cm was used to pierce it.

〔durability〕

(1) Humidity resistance test

The durability test at 60 占 폚 and 90% RH for 168 hours was evaluated as follows.

(2) Heat resistance test

The durability test at 80 DEG C for 168 hours was evaluated as follows.

(3) Heat cycle test

The durability test was carried out for 168 cycles (168 hours) as one cycle in which the test piece was allowed to stand at -30 占 폚 for 30 minutes and then left at 80 占 폚 for 30 minutes.

(Evaluation standard)

The presence or absence of defects (foaming, streaking, lifting, peeling) for each of the above items (1) to (3) was evaluated.

◎ · · · No defect

○ ... a defect within 0.5 mm from the end of the polarizer

X: defects in the inside of 0.5 mm from the end of the polarizing plate

[Leak resistance]

In the durability test at 80 DEG C for 150 hours, the light leakage resistance was measured and evaluated as described below. For Example 30, measurement and evaluation were carried out in an endurance test at 50 DEG C and 90% RH for 150 hours.

(Measuring device)

&Quot; EyeScale &quot; (manufactured by Eye Systems Co., Ltd.)

(Measuring conditions)

· Camera lens iris No.16

· Camera GAIN10

· Shutter speed 1/1000

· Luminance 9000

The light leakage observation sample is placed on the backlight set at the light source side,

· Camera lens aperture No.4

· Camera GAIN6

· Shutter speed 1/30

And the light leakage state was observed with the naked eye of the image put into the water.

The evaluation criteria are as follows.

(Evaluation standard)

◎ No light leakage.

○ · · · slight leakage of light

× · · · Clear light leakage

Further, in Comparative Examples 11 to 15, the light leakage could not be evaluated because the polarizing plate was peeled off.

[Adhesion and reworkability]

The resultant polarizing plate with a pressure-sensitive adhesive layer was cut into a width of 25 mm and attached to an alkali-free glass (Eagle XG manufactured by Corning Incorporated), subjected to autoclave treatment (50 DEG C, 0.5 MPa, 20 minutes) For 24 hours, and subjected to a 180 degree peel test to measure the adhesive strength, and the reworkability was evaluated as follows.

(Evaluation standard)

◎ · · · 10N or less

○ ... greater than 10 N and less than 15 N

× 15 N or more

〔retention〕

The polarizing plate with a pressure-sensitive adhesive layer was cut to a size of 25 mm x 25 mm, the release sheet was peeled off, the pressure-sensitive adhesive layer side was stuck to a polished SUS plate and subjected to a load of 1 kg under the condition of 80 deg. C and measured according to JIS Z 0237 I evaluated the discrepancy. The evaluation criteria are as follows.

(Evaluation standard)

◎ ... No deviation after 1440 minutes (N.C)

○: Less than 10 mm after 1440 minutes has elapsed

X 占 10 mm or more deviates after 1440 minutes

[Antistatic property]

The pressure-sensitive adhesive layer polarizer was allowed to stand in an atmosphere of 23 ° C. and 50% RH for 24 hours. Thereafter, a surface resistivity measuring device ("Hiresta-UPMCP-HT450", manufactured by Mitsubishi Kagaku International Inc.) To measure the surface resistivity of the pressure-sensitive adhesive layer. The evaluation criteria are as follows.

(Evaluation standard)

◎ ... 1.0E + 11 Ω / ㎠ or less

O: 1.0E + 11? / Cm2 or more, 1.0E + 12? / Cm2 or less

占 ... 1.0E + 12? / Cm2 or more

[Transparency]

The pressure sensitive adhesive composition solutions of Examples 17 to 30 and Comparative Examples 10 to 15 were applied to a polyester releasable release sheet so that the thickness after drying was 25 탆 and dried at 100 캜 for 3 minutes. Ester-based heavy-duty release sheet was attached and aged for 7 days under conditions of 23 캜 and 65% RH to obtain a pressure-sensitive adhesive sheet-attached sheet. The lightly peelable sheet of the obtained sheet was peeled off and the heavy-weight recycled sheet adhered to the non-alkali glass (Eagle XG manufactured by Corning Incorporated) was removed and the haze was measured using a haze meter "HAZE MATER NDH2000" (manufactured by Nippon Denshoku Kogyo Co., ) Was measured to evaluate transparency.

In addition, this apparatus complies with JIS K 7361-1. The evaluation criteria are as follows.

(evaluation)

○ · · · Less than 1% haze

× ... Haze is 1% or more

From the evaluation results shown in Table 4, it can be seen that the pressure-sensitive adhesives of the compositions of Examples 17 to 30 have high transparency because they are excellent in compatibility with each other among the acrylic resins, and have excellent durability performance Heat cycle performance), light leakage resistance, reworkability, and antistatic property.

On the other hand, from Table 3, it can be seen from Table 3 that in Comparative Examples 1 to 4 in which an acrylic resin (B'-1) containing no monomer (b1) having a non-reactive functional group as a polymerization component was blended with the acrylic resin (A) It can be seen that the compatibility with each other is poor.

From Tables 3 and 4, in Comparative Examples 5 to 8, 10 and 11 in which the acrylic resin (A'-1) and the acrylic resin (B) were blended with the content of the reactive functional group-containing monomer (a1) Acrylic resins are excellent in compatibility with each other, but the durability is deteriorated.

From Table 3 and Table 4 it can be seen that the acrylic resin (A'-1) having a small content of the reactive functional group-containing monomer (a1) as the polymerization component and the acrylic resin (B'-1) were blended in Comparative Examples 9 and 12 to 15, it was found that the acrylic resin was excellent in compatibility with each other, but the durability and leakage resistance were poor.

Although the present invention has been described in detail with reference to specific embodiments, it is apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the present invention. This application is based on Japanese Patent Application (Japanese Patent Application No. 2014-147865) filed on July 18, 2014, the content of which is incorporated herein by reference.

The pressure-sensitive adhesive composition of the present invention is excellent in pressure-sensitive adhesives exhibiting excellent durability performance (in particular, resistance to heat cycle) when a polarizing plate and a glass substrate are stuck, It is extremely useful as a pressure-sensitive adhesive for obtaining a pressure-sensitive adhesive layer laminated optical member, particularly a pressure-sensitive adhesive layer polarizing plate, and an image display device obtained by using the pressure-sensitive adhesive layer for an optical member.

Claims (11)

A pressure-sensitive adhesive composition comprising an acrylic resin (A) obtained by polymerizing a polymerization component containing a reactive functional group-containing monomer (a1), and an acrylic resin (B) obtained by polymerizing a polymerization component not containing a reactive functional group-
, Wherein the polymerization component of the acrylic resin (A) contains 2.5 to 30 wt% of the reactive functional group-containing monomer (a1), and the polymerization component of the acrylic resin (B) includes the non-reactive polar functional group- By weight. The method according to claim 1,
The content of the non-reactive polar functional group-containing monomer (b1) in the polymerization component of the acrylic resin (B) is 0.1 to 30% by weight. The method according to claim 1 or 2,
Wherein the reactive functional group-containing monomer (a1) is at least one member selected from the group consisting of a hydroxyl group-containing monomer and a carboxyl group-containing monomer. 4. The method according to any one of claims 1 to 3,
The non-reactive polar functional group-containing monomer (b1) is at least one selected from the group consisting of amide group-containing monomers, tertiary amino group-containing monomers and ether group-containing monomers. 5. The method according to any one of claims 1 to 4,
Wherein the acrylic resin (A) has a weight average molecular weight of 1,000,000 or more. 6. The method according to any one of claims 1 to 5,
Wherein the acrylic resin (B) has a weight average molecular weight of 1,000,000 or more. 7. The method according to any one of claims 1 to 6,
Wherein the content ratio [(A) :( B)] (weight ratio) of the acrylic resin (A) to the acrylic resin (B) is from 100: . The method according to any one of claims 1 to 7,
And a crosslinking agent (C). The method of claim 8,
Wherein the crosslinking agent (C) is at least one member selected from the group consisting of isocyanate crosslinking agents and epoxy crosslinking agents. The pressure-sensitive adhesive composition according to any one of claims 1 to 9, which is crosslinked by a crosslinking agent (C). A pressure-sensitive adhesive for a polarizing plate, comprising the pressure-sensitive adhesive according to claim 10.