JPH08302320A - Pressure-sensitive adhesive composition - Google Patents

Abstract

PURPOSE: To obtain a pressure-sensitive adhesive compsn. reduced in changes in cohesion and adhesion with time even at high temps. or under high-temp. and high-humidity conditions, excellent in adhesion to a curved surface, and suitable for bonding an optical film to a base material. CONSTITUTION: An acrylic resin contg. functional groups reactive with a carboxyl group is blended with an alkoxysilane compd. having a carboxyl group and a crosslinking agent, and pref. further blended with an amine compd. and a crosslinking assistant to obtain the objective compsn.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel pressure-sensitive adhesive composition which has a small change in cohesive force and adhesive force with time even under high temperature or high temperature and high humidity and is excellent in curved surface adhesive force. In particular, the present invention relates to a pressure-sensitive adhesive composition suitable for adhering an optical film and a substrate.

[0002]

2. Description of the Related Art Generally, conventionally used pressure-sensitive adhesive compositions or their applied products such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets can be adhered to various surfaces of an application body at room temperature under a pressure of about finger pressure. Is used for. However, when the composition or its applied article is exposed to high temperature or high temperature and high humidity conditions after being adhered to the adherend surface, it has a drawback of peeling from the adherend surface, and its application is also restricted. It is the actual situation.

In order to solve these problems, a pressure-sensitive adhesive composition exhibiting adhesiveness that can be used even under conditions of high temperature, high humidity, or water, for example, vinyl silane, epoxy silane, methacryl silane is added to an acrylic polymer. A pressure-sensitive adhesive composition containing at least one selected from the group (Japanese Patent Publication No. 62-30233), and an adhesive containing an epoxy group-containing silane compound in an acrylic resin having a hydroxyl group capable of reacting with an epoxy group. Composition (JP-A-61-7)
369), a pressure-sensitive adhesive composition obtained by blending an isocyanate group-containing organosilicon compound with an acrylic resin copolymerized with an ethylenically unsaturated monomer capable of reacting with an isocyanate group (JP-A-1-158080). Proposed.

[0004]

However, in the technique disclosed in Japanese Patent Publication No. 62-30233, the bonding strength between the acrylic polymer and the silane compound is weak, so that the improvement of the adhesive strength is small and the cohesive strength is small. It is still unsatisfactory in terms of obtaining a pressure-sensitive adhesive composition whose change with time is small. Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 61-7369, the reaction between the glycidyl group and the hydroxyl group-containing acrylic resin is slow, and it is difficult to cure at room temperature. When a catalyst is used, water resistance and moisture resistance are extremely reduced.

Further, in the technique disclosed in Japanese Patent Application Laid-Open No. 1-158087, although the above-mentioned room temperature curability is improved, a pressure-sensitive adhesive composition which does not deteriorate in water resistance and humidity resistance with time is obtained. An adherend with a curved surface that requires adhesive strength,
For example, the adhesive performance to a curved surface portion of a film type liquid crystal or a liquid crystal display body having a curved surface in a label application or an optical application (adhesive application between an optical film and a glass substrate) in which a curved surface is selected as an adherend is described in the above publication. Including the above, no consideration is given, and the application of the pressure-sensitive adhesive composition is also restricted. As a result of a detailed study by the present inventor on this point, in consideration of diversification of pressure-sensitive adhesive applications, sufficient adhesiveness cannot be obtained by the above technique, and it is still necessary to obtain a sufficiently satisfactory pressure-sensitive adhesive composition. There is room for improvement.

On the basis of the above background, therefore, there is little change in cohesive force and adhesive force with time even under high temperature or high temperature and high humidity, and a curved surface is selected as an adherend or a film type liquid crystal having a curved surface or It is desired to develop a pressure-sensitive adhesive composition that is excellent in the adhesive force (curved surface adhesive force) to an adherend having a curved surface such as a liquid crystal display. In particular, polarizing plate, retardation plate,
In optical applications such as elliptically polarizing plates, the application frequency thereof is high, and such adhesive compositions can be greatly utilized.

[0007]

However, as a result of earnest studies to solve the above problems, the present inventor has found that an acrylic resin (A) containing a functional group capable of reacting with a carboxyl group and an alkoxy having a carboxyl group. The present invention was completed by finding that an adhesive composition containing a silane compound (B) and a crosslinking agent (C) solves the above problems.

The greatest feature of the present invention is that an acrylic resin (A) having a functional group capable of reacting with a carboxyl group and an alkoxysilane compound (B) having a carboxyl group are employed. When blended with C),
It exhibits very excellent cohesive strength, adhesive strength, or curved surface adhesive strength with little change over time even at high temperature or high temperature and high humidity.
Further, in the present invention, the effect of the present invention can be more remarkably exhibited by further containing the amine compound (D) in the pressure-sensitive adhesive composition.

Further, in the present invention, in addition to the acrylic resin (A) having a functional group capable of reacting with a carboxyl group, the alkoxysilane compound (B) having a carboxyl group and the crosslinking agent (C), a crosslinking auxiliary agent is further added. As (E), when at least one compound selected from a polyol compound, a melamine compound and divinylbenzene is also used in combination, the excellent effects of the present invention are exhibited. By using the pressure-sensitive adhesive composition of the present invention for adhesion to a glass substrate in optical applications such as a polarizing film and a retardation film, it is possible to provide an optical laminate having excellent durability and small change in optical properties. . In the present invention, the term “carboxyl group” used in the present invention means not only a free carboxyl group but also an acid anhydride structure.

The present invention will be specifically described below.
The acrylic resin (A) having a functional group capable of reacting with a carboxyl group of the present invention may be any acrylic resin having a functional group capable of reacting with a carboxyl group of the alkoxysilane compound (B) having a carboxyl group. , A soft monomer (main monomer) component having a low glass transition temperature, a hard comonomer component having a high glass transition temperature, and a monomer component having a functional group capable of reacting with a carboxyl group.

As the main monomer component, the number of carbon atoms of the alkyl group such as ethyl acrylate, n-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, cyclohexyl acrylate is 2 To about 12 acrylic acid alkyl esters, n-butyl methacrylate, isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, cyclohexyl methacrylate, and other methacrylic acids having 4 to 12 carbon atoms. Examples of the comonomer component include alkyl acrylates and the like, and alkyl methacrylates such as methyl acrylate, methyl methacrylate, ethyl methacrylate, and propyl methacrylate having 1 to 3 carbon atoms of alkyl groups, and vinyl acetate. , Acrylonitrile, methacrylonitrile, styrene, and the like. Further, a monomer generally used in the synthesis of acrylic resins such as an acrylic acid alkyl ester or a methacrylic acid alkyl ester in which an alkyl group is substituted with an aromatic ring group, a heterocyclic group, a halogen atom or the like is used as a pressure sensitive adhesive of the present invention. It can also be used for the synthesis of resin.

Further, as the monomer component having a functional group which reacts with a carboxyl group, for example, a carboxyl group-containing monomer, an epoxy group-containing monomer, a hydroxyl group-containing monomer, an amino group-containing monomer, an amide group, an N-substituted amide group-containing monomer, etc. Is mentioned. For example, as the carboxyl group-containing monomer, acrylic acid, methacrylic acid, monocarboxylic acids such as crotonic acid, maleic acid, fumaric acid, citraconic acid, glutaconic acid, polycarboxylic acids such as itaconic acid, and their anhydrides and the like. There are allyl glycidyl ether, glycidyl methacrylate, etc. as the epoxy group-containing monomer, and 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) as the hydroxyl group-containing monomer. ) Acrylate, 4-hydroxybutyl (meth) acrylate, 3
-Chloro-2-hydroxypropyl (meth) acrylate, diethylene glycol mono (meth) acrylate, etc., N-methylol acrylamide, allyl alcohol, etc.

The amino group-containing monomer includes dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylamide and the like, and the amide group and the N-substituted amide group-containing monomer are , (Meth) acrylamide, N-methyl (meth) acrylamide, N-ethyl (meth) acrylamide, N-ethoxymethyl (meth)
There are acrylamide, N-propoxymethyl (meth) acrylamide, N-butoxymethyl (meth) acrylamide, N-tert-butylacrylamide, N-octylacrylamide, diacetone acrylamide and the like.

Among the functional group-containing monomer components,
It is particularly preferable to use a carboxyl group-containing monomer, an epoxy group-containing monomer, a hydroxyl group-containing monomer, or an amino group-containing monomer. The content of the main monomer component cannot be unconditionally specified depending on the type and content of the comonomer component or the functional group-containing monomer component to be contained, but
Generally, it is preferable to contain the main monomer in an amount of 50% by weight or more. The content of the monomer component containing a functional group that reacts with a carboxyl group is 0.001 to 50% by weight, preferably 0.001 to 25% by weight, and more preferably 0.01 to 25% by weight. desired.

The acrylic resin containing a functional group which reacts with a carboxyl group of the present invention is a main monomer, a comonomer,
Further, it is easily produced by a method well known to those skilled in the art, such as radical copolymerization of a monomer having a functional group capable of reacting with a carboxyl group in an organic solvent.

Examples of the organic solvent used in such radical copolymerization include aromatic hydrocarbons such as toluene and xylene, esters such as ethyl acetate and butyl acetate, and aliphatic alcohols such as n-propyl alcohol and iso-propyl alcohol. Examples thereof include ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone, and cyclohexanone. Further, as the polymerization catalyst used for radical copolymerization, azobisisobutyronitrile, benzoyl peroxide, di-t-
Butyl peroxide, cumene hydroperoxide and the like can be mentioned as specific examples. Further, the polymerization conditions are known to those skilled in the art.

In the pressure-sensitive adhesive composition of the present invention, as described above, the acrylic resin (A), the alkoxysilane compound having a carboxyl group (B) and the crosslinking agent (C).
Is contained. The alkoxysilane compound (B) having a carboxyl group is not particularly limited, and examples thereof include 3-triethoxysilylpropylsuccinic anhydride (trade name: GF-20, Wacke) represented by the following chemical formula 1.
r-Chemie GmbH), 3-triethoxysilylpropyl succinic acid, 3-trimethoxysilylpropyl succinic acid (anhydride), 3-methyldimethoxysilylpropyl succinic acid (anhydride), 3- Methyldiethoxysilylpropyl succinic acid (anhydride), 1-carboxy-3-triethoxysilylpropyl succinic anhydride represented by the following chemical formula 3 and the like can be mentioned. Among them, a silane compound having an acid anhydride structure is particularly preferable, and 3-triethoxysilylpropylsuccinic anhydride,
1-Carboxy-3-triethoxysilylpropylsuccinic anhydride and the like are preferably used from the viewpoint of adhesive properties.

[0018]

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The content of the alkoxysilane compound (B) having a carboxyl group is 0.0001 to 10 parts by weight based on 100 parts by weight of the acrylic resin (A) containing a functional group that reacts with the carboxyl group. , Preferably 0.0005 to 7 parts by weight, more preferably 0.001 to 5 parts by weight. Such content is 0.0
If it is less than 001 parts by weight, the effect of addition is not obtained, and if it exceeds 10 parts by weight, the cohesive force is lowered, and the excellent effect of the present invention cannot be obtained.

Further, in the present invention, in addition to the alkoxysilane compound (B), an epoxy silane,
Other silane compounds such as acrylic silane, mercapto silane, and hydroxyl silane can also be used in combination. The cross-linking agent (C) is not particularly limited, but an isocyanate compound, an epoxy compound, an aldehyde compound, an amine compound, a metal salt, a metal alkoxide, a metal chelate compound, an ammonium salt, a hydrazine compound and the like can be used. It is illustrated.

Among the cross-linking agents (C), the isocyanate compounds include tolylene diisocyanate, hydrogenated tolylene diisocyanate, trimethylol propane tolylene diisocyanate adduct, trimethylol propane xylylene diisocyanate adduct, triphenyl methane triisocyanate, Examples thereof include methylenebis (4-phenylmethane) triisocyanate, isophorone diisocyanate, and their ketoxime block products, phenol block products, isocyanurates, and the like.

Examples of the epoxy compound include bisphenol A / epichlorohydrin type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin di- or triglycidyl ether, 1,6-hexanediol diglycidyl ether, trimethylolpropane. Triglycidyl ether, diglycidyl aniline, diglycidyl amine,
N, N, N ', N'-tetraglycidyl m-xylenediamine, 1,3-bis (N, N'-diglycidylaminomethyl) cyclohexane and the like can be mentioned.

Examples of aldehyde compounds include glyoxal, malondialdehyde, succindialdehyde, maleindialdehyde, glutardialdehyde, formaldehyde, acetaldehyde, benzaldehyde and the like. As the amine compound, hexamethylenediamine, triethyldiamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethyltetramine, isophoronediamine, amino resin,
Melamine resin etc. are mentioned.

As the metal salt, aluminum, iron, copper,
Salts of polyvalent metals such as zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, zirconium, etc., such as chlorides, bromides, nitrates, sulfates, acetates, etc., such as cupric chloride, aluminum chloride, and chloride chloride. Examples thereof include ferric iron, stannic chloride, zinc chloride, nickel chloride, magnesium chloride, aluminum sulfate, copper acetate and chromium acetate. Examples of metal alkoxides include tetraethyl titanate, tetraethyl zirconate, and aluminum isopropionate.

Examples of the metal chelate compound include acetylacetone and acetoacetate ester coordination compounds of polyvalent metals such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium. . As an ammonium salt,
Examples thereof include ammonium chloride, ammonium sulfate, ammonium acetate, ammonium propionate and the like. Examples of the hydrazine compound include hydrazine, hydrazine hydrate, and their inorganic salts such as base salts, sulfates and phosphates, and organic acid salts such as formic acid and oxalic acid.

In the present invention, among the above-mentioned crosslinking agents (C), isocyanate compounds are preferable, and among them, tolylene diisocyanate adduct of trimethylolpropane is most effective. The content of the cross-linking agent (C) is 0.1% with respect to 100 parts by weight of the acrylic resin (A) containing a functional group that reacts with a carboxyl group.
The amount is 01 to 10 parts by weight, preferably 0.1 to 7 parts by weight, and more preferably 0.3 to 5 parts by weight. If the content is less than 0.01 parts by weight, curing will not be sufficient and will be unsatisfactory under high temperature conditions. On the other hand, if it exceeds 10 parts by weight, curing will be promoted too much and the adhesive strength will be reduced, which is not preferable.

In the present invention, it is preferable to further contain an amine compound (D) in addition to the above, so that the effect of the present invention can be remarkably exhibited. The amine compound (D) is not particularly limited, and examples thereof include triethylenediamine,
N, N, N ', N'-tetramethyltrimethylenediamine, methyliminobispropylamine, aminoethylpiperazine, N, N, N', N'-tetramethylethylenediamine, hexamethylenetetramine, 2,4,6- Tris (dimethylaminomethyl) phenol, 2-methylimidazole, pyridine, 1-cyanoethyl-2-methylimidazole, 1,8-diazabicyclo-7-undecene, benzyldimethylamine, triethanolamine, benzyltrimethylammonium chloride, tributylamine, Examples thereof include boron trifluoride-dimethylamine complex, among which triethylenediamine, N, N,
N ', N'-tetramethyltrimethylene diamine, N,
N, N ', N'-tetramethylethylenediamine, 2-
Methylimidazole is particularly preferred.

The content of the amine compound (D) is 0.0001 to 100 parts by weight with respect to 100 parts by weight of the acrylic resin (A) containing a functional group that reacts with a carboxyl group.
It is desired that the amount is 10 parts by weight, preferably 0.001 to 10 parts by weight, and more preferably 0.001 to 5 parts by weight. If the content is less than 0.0001 parts by weight, the effect of addition cannot be obtained, and if it exceeds 10 parts by weight, the cohesive force decreases, and the effect of the present invention is not markedly exhibited.

Further, in the present invention, in addition to the alkoxysilane compound (B) having a carboxyl group and the crosslinking agent (C),
Furthermore, it is preferable to mix one or more polyol compounds, melamine compounds and divinylbenzene as the crosslinking aid (E). Regarding such content, 0.001 to 50 parts by weight, preferably 0.01 to 3 parts by weight in the case of a polyol compound, relative to 100 parts by weight of the acrylic resin (A) containing a functional group that reacts with a carboxyl group.
0 parts by weight, 0.001-10 in the case of melamine compounds
By weight, preferably 0.001 to 0.5 parts by weight, and in the case of divinylbenzene, 0.001 to 10 parts by weight, preferably 0.001 to 5 parts by weight, and the effect of the present invention is remarkable. Can be demonstrated.

The polyol type compound is not particularly limited, and polyether polyol, polyester polyol, hydroxyl group-containing polybutadiene polyol,
Acrylic polyols, castor oil derivatives, tall oil derivatives, and other nitrogen-free polyols are mentioned, and among them, trimethylolpropane, 1,4-butanediol, polytetramethylene ether glycol,
Examples thereof include ethylene glycol, propylene glycol, 3-methylpentane-1,3,5-triol, and the like. Preferable examples include nitrogen-containing polyol compounds represented by the following chemical formulas 4 and 6. Specifically, as chemical formula 4, triethanolamine, methyldiethanolamine, polyoxyethylenestearylamine, polyoxyethylenelaurylamine, preferably methyldiethanolamine, polyoxyethylenestearylamine, and chemical formula 6 are N, N, N '. , N′-tetrakis (2-hydroxypropyl) ethylenediamine,
Adeka quadrol (Asahi Denka Kogyo Co., Ltd.) can be mentioned.

[0031]

[Chemical 4] Here, R and R ′ are alkyl groups, R ₁ is hydrogen, an alkyl group, an acyl group, a phenyl group, or one of the following chemical formulas 5, and m, n, k, and l are integers of 0 or more (provided that , M and n, and k and l do not become 0 at the same time.).

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[0032]

[Chemical 6] Here, R and R'are alkyl groups, X is an alkylene group or a phenylene group, and a, b, m, n, k, l, x and y are integers of 0 or more (provided that a, b, m and n, k and l, x and y
Neither becomes 0 at the same time. ) And p is an integer of 1 or more.

The melamine-based compound is not particularly limited, but a compound represented by the following chemical formula 7 is preferable. Specifically, R ₂ is hydrogen (9% by weight), —CH ₂ OH (31% by weight), Super Beckamine J-820-60 (Dainippon Ink and Chemicals, Inc.) consisting of —CH ₂ OBu (60% by weight) can be mentioned.

[0034]

[Chemical 7] Here, R ₂ is hydrogen or —CH ₂ —O—R ₂ ′ (however,
R ₂ ′ is hydrogen or an alkyl group), R ₃ is R ₂ or a bond formed by condensation, and r is an integer of 1 or more.

When divinylbenzene is used, it is preferable that the obtained pressure-sensitive adhesive composition is coated on a substrate, laminated on a film or the like, and then irradiated with an electron beam if necessary.
Regarding electron beam irradiation, 0.1 Mrad to 10 Mrad
It is preferable to irradiate the irradiation amount of. In the present invention, when the amine compound (D) and the crosslinking aid (E) are used in combination, the adhesive property is most excellent.

In the present invention, an acrylic resin (A) having a functional group capable of reacting with the carboxyl group, an alkoxysilane compound (B) having a carboxyl group, a crosslinking agent (C), and an amine compound (D). ), A cross-linking aid (E), and the like, and there is no particular limitation on the compounding method thereof, batch charging, the acrylic resin (A), the alkoxysilane compound (B), the cross-linking agent ( C), the amine compound (D), and the crosslinking aid (E) may be arbitrarily mixed in advance, and the remaining components may be mixed later, and further, the alkoxysilane compound (B) having a carboxyl group. To coexist during the production of the acrylic resin (A) containing a functional group that reacts with a carboxyl group, that is, during the polymerization of each of the above monomer components, or to contain a functional group that reacts with a carboxyl group That acrylic resin (A) and the alkoxysilane compound having a carboxyl group (B) 10
The reaction is carried out at -50 ° C for 1 to 50 hours (using a reaction catalyst if necessary), and further, a monomer having a functional group that reacts with a carboxyl group and an alkoxysilane compound (B) having a carboxyl group are preliminarily used. 1 to 5 at ~ 50 ° C
The reaction may be carried out for 0 hours (using a reaction catalyst if necessary), a silane compound may be added, and this may be copolymerized with another acrylic monomer component.

Thus, the pressure-sensitive adhesive composition of the present invention has a small change in cohesive force and adhesive force with time even under high temperature or high temperature and high humidity, and has an excellent effect on the curved adhesive force peculiar to the present invention. It is an agent composition. Regarding the use of such a pressure-sensitive adhesive composition, after being dissolved in an organic solvent such as toluene, ethyl acetate, methyl ethyl ketone, or acetone, it is applied to a substrate or a film such as a release film, and then 30 to 170.
It is dried and cured at a drying temperature of C, preferably 40-150 C, to obtain its tacky properties. Then, the pressure-sensitive adhesive composition is effectively used for various pressure-sensitive adhesive applications such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets, and further laminated on various substrates. The base material is not particularly limited, but a metal plate of any material such as a stainless plate, an aluminum plate, a steel plate, a copper plate, a polyethylene plate, a polypropylene plate, a melamine plate,
It can be attached to the surface of a synthetic resin decorative plate such as a phenol plate, a plywood, a single plate, a so-called plate-shaped product such as a glass plate, a rod-shaped product, pottery or various molded products. If necessary, the electron beam irradiation may be performed as described above after the bonding.

Further, the pressure-sensitive adhesive composition of the present invention exhibits a very excellent effect in bonding a substrate, particularly a glass substrate, to an optical film. That is, by using the pressure-sensitive adhesive composition, when used in a high temperature or high temperature and high humidity environment, appearance defects such as foaming and peeling of the pressure-sensitive adhesive layer do not occur, and heat resistance and wet heat resistance are excellent, and further, optical An optical laminate having excellent characteristics can be obtained.

The optical film used in the present invention is not particularly limited as long as it has optical characteristics.
It is preferable to use a polarizing film, a retardation film, an elliptically polarizing film, or the like, and by using the pressure-sensitive adhesive composition of the present invention for bonding these optical films and a glass substrate, heat resistance, moisture heat resistance and optical characteristics are excellent. Thus, an optical laminate of film / glass substrate can be obtained. In the present invention, a protective layer is mainly provided on an optical film such as a polarizing film, a retardation film, and an elliptical polarizing film, but unless otherwise specified, it is referred to as an optical film with or without a protective layer.

The optical laminate will be described in detail below. In the present invention, for example, mainly a polyvinyl alcohol-based polarizing film as a substrate, a polarizing plate provided with a protective layer if necessary, or a polyvinyl alcohol-based or polycarbonate-based retardation film as a substrate, which is necessary for this. Accordingly, the pressure-sensitive adhesive layer and the release film are added to a retardation plate provided with a protective layer, an elliptically polarizing plate in which a polarizing film and a retardation film are combined, and the like. As a method for adding the pressure-sensitive adhesive layer and the release film, the pressure-sensitive adhesive layer is provided on the release film, and the optical film is attached thereon, or vice versa. The method of sticking a release film on is usually adopted.

The optical film having the pressure-sensitive adhesive layer thus obtained is appropriately cut at the time of use, the release film is peeled off, and the glass is adhered to the other base material such as glass or other base material, and the liquid crystal display device Used for glare or sunglasses. Further, the optical film having the pressure-sensitive adhesive layer is used for a reflective or semi-transmissive liquid crystal display panel by further providing a reflective plate and / or a translucent layer. This reflector is usually made of aluminum, silver or other foil,
Boards are used. Further, as the semitransparent layer, the reflectance and the transmittance are selected so that both of the reflection type and the transmission type can be used, and the material is appropriately selected.

The retardation film is not particularly limited and includes polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polystyrene, polysulfone, polyether sulfone, polyvinylidene fluoride / polymethylmethacrylate, liquid crystal polymer. , Triacetyl cellulose resin, cyclic polyolefin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride and the like are used, but mainly polycarbonate and polyvinyl alcohol resin film are used. Polyvinyl alcohol-based resins are usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. However, a small amount of unsaturated carboxylic acids (including salts, esters, amides, nitriles, etc.), olefins, vinyl ethers, It may contain a component which is copolymerizable with vinyl acetate, such as a saturated sulfonate. Also, polyvinyl alcohol was reacted with aldehydes in the presence of acid,
Examples thereof include so-called polyvinyl acetal resins such as polybutyral resins and polyvinyl formal resins, and polyvinyl alcohol derivatives. Average degree of polymerization is 500-
10,000, the saponification degree is 80 to 100 mol%,
It is preferably uniaxially stretched about 1.01 to 4 times.

On the other hand, the polarizing film has an average degree of polymerization of 15
00 to 10000, saponification degree 85 to 100 mol% of the above polyvinyl alcohol resin as a raw film,
A uniaxially stretched film dyed with an aqueous solution of iodine-potassium iodide or a dichroic dye (a draw ratio of 2 to 10 times, preferably about 3 to 7 times) is used.

Examples of the protective layer include conventionally known cellulose acetate type films, acrylic type films, polyester type resin films, polyolefin type resin films, polycarbonate type films, polyether ether ketone type films, polysulfone type films and the like. However, a cellulose acetate film such as a cellulose triacetate film is preferably used. Further, if necessary, it is possible to blend an ultraviolet absorber such as a salicylic acid ester-based compound, a benzophenol-based compound, a benzotriazole-based compound, a cyanoacrylate-based compound, or a nickel complex salt-based compound into the resin film.

The optical layered body of the present invention is not particularly limited and may have various layer constitutions. For example, protective layer / polarizing film / protective layer / pressure-sensitive adhesive layer of the present invention / glass (or release film), functional layer / protective layer / polarizing film / protective layer / pressure-sensitive adhesive layer of the present invention / glass (or release layer) Type film), retardation film / pressure-sensitive adhesive layer of the present invention / glass (or release film), protective layer / retardation film / protective layer / pressure-sensitive adhesive layer of the present invention / glass (or release film),
(Protective layer /) polarizing film (/ protective layer) / acrylic pressure-sensitive adhesive layer / (protective layer /) retardation film (/ protective layer) / pressure-sensitive adhesive layer of the present invention / glass (or release film), functional layer / Protective layer / Polarizing film (/ Protective layer) / Acrylic adhesive layer / (Protective layer /) Retardation film (/ Protective layer) / Adhesive layer of the present invention / Glass (or release film), Masking layer / Polarizing film (/ protective layer) / acrylic adhesive layer / (protective layer /) retardation film (/ protective layer) / adhesive layer of the present invention / glass (or release film), (protective layer /)
Retardation film (/ protective layer) / acrylic adhesive layer /
(Protective layer /) polarizing film (/ protective layer) / pressure-sensitive adhesive layer of the present invention / glass (or release film), masking layer / retardation film (/ protective layer) / acrylic pressure-sensitive adhesive layer / (protective layer / ) Polarizing film (/ protective layer) / pressure-sensitive adhesive layer of the present invention / glass (or release film), (glass or release film /) pressure-sensitive adhesive layer of the present invention / (protective layer /) retardation film (/ protection) Layer) / acrylic adhesive layer / (protective layer /) polarizing film (/ protective layer) / adhesive layer of the present invention / glass (or release film).

Examples of the functional layer include a hard coat layer, an antireflection layer and an antiglare layer. Further, as the masking layer, a synthetic resin film such as a polyethylene film or a polyethylene terephthalate film having a thickness of about 10 to 100 μ is used, and as the release film, release silicone, wax, paraffin,
A release paper provided with a release layer made of chromium chloride stearate or a synthetic resin such as a thermoplastic resin or a thermosetting resin, or a synthetic resin-based one having a polyester film, a polypropylene film, a polyethylene terephthalate film as a base material is used. . Furthermore, regarding the lamination of the protective layer and the polarizing film or the retardation film, natural or synthetic rubber, an acrylic resin, a butyral resin, an epoxy resin, a polyester resin, a polyamide resin, a polyvinyl alcohol resin, or the like is used as a main component. The adhesive or pressure-sensitive adhesive or the like can be used for adhesion by an air-drying method, a chemical curing method, a heat curing method, a heat melting method or the like.

[0047]

[Working] The pressure-sensitive adhesive composition of the present invention comprises an acrylic resin (A) containing a functional group capable of reacting with a carboxyl group, an alkoxysilane compound (B) having a carboxyl group, a cross-linking agent (C), particularly an isocyanate type. Since it contains a compound, preferably an amine compound (D), a polyol compound as a cross-linking aid (E), a melamine compound, and divinylbenzene, it has cohesive strength and adhesion even under high temperature or high temperature and high humidity. It shows a small change in force over time and has an excellent effect on curved surface adhesiveness, and when used for adhesion of optical film and base material, it has excellent durability not to cause foaming or peeling of the adhesive. Not only that, even if it is left in a high temperature and high humidity environment for a long time, its optical characteristics are not deteriorated. Utilizing such characteristics, it is used for liquid crystal displays, and is particularly useful for vehicles, various industrial instruments, and displays of household electric appliances.

[0048]

EXAMPLES The present invention will be described in more detail below with reference to examples. In the examples, "part" and "%" are based on weight unless otherwise specified. Example 1 100 parts of a mixture of n-butyl acrylate: acrylic acid = 95: 5 (weight ratio) was added with 0.1 part of benzoyl peroxide as a polymerization initiator and polymerized in toluene to give an acrylic copolymer. A polymer solution was obtained. Into the copolymer solution, 3-triethoxysilylpropyl succinic anhydride (trade name: G
F-20, Wacker-Chemie GmbH)
1.0 part of Coronate L (manufactured by Nippon Polyurethane Co.), which is an isocyanate compound, was added as a crosslinking agent.
The mixture was thoroughly mixed to obtain an adhesive composition. With respect to the obtained pressure-sensitive adhesive composition, the adhesive strength, cohesive strength and curved surface adhesive strength were evaluated. The evaluation methods of the adhesive force, cohesive force and curved surface adhesive force are as shown below.

(Adhesive Strength) The above adhesive composition was dissolved in toluene, applied on a polyethylene terephthalate film, and dried at 100 ° C. for 2 minutes (coating thickness after drying was 25 μm.
m) and reciprocate it three times with a manual roller according to JIS Z 0237 (size: width 25 mm, length 1
It was crimped to 80 mm). The sample was autoclaved (50 ° C., 15 minutes, 5 kg / cm ² ), and kept at 60 ° C. for 1 hour.
After heat treatment for 2 hours and leaving it under the condition of 20 ° C. and 65% RH for 1 hour, using an apparatus according to JIS B 7721,
The adhesive strength (kg / 25 mm) was measured by the 90-degree pulling method according to JIS Z 0237. The pulling rate was 200 mm / min.

(Cohesive Strength) A polyethylene terephthalate film (size: coated with the pressure-sensitive adhesive composition as described above).
A glass plate (size: width 40 mm, length 80 mm) having a width of 25 mm and a length of 150 mm was crimped back and forth three times by a manual roller according to JIS Z 0237. The sample is autoclaved (50 ° C., 15 minutes, 5 kg / cm ² ).
Then, after leaving it for 1 hour under the condition of 20 ° C. and 65% RH,
A load of 1 kg was applied to the end portion, and the size of deviation (mm) after 48 hours at 70 ° C. was measured according to JIS Z 0237 and evaluated according to the following criteria. A: Less than 0 to 0.5 (mm) O: Less than 0.5 to 5.0 (mm) B: Less than 5.0 to 10.0 (mm) X: 10.0 (Mm) or more

(Curved surface adhesion) A test piece similar to the above with a width of 25 mm and a length of 66 mm was attached to the curved surface of a glass cylinder having a diameter of 30 mmφ using the weight of the cylinder (200 g), and autoclaved (50 ° C., 15 ° C.). Min, 5 kg / cm ² )
Then, leave it at 40 ° C for 24 hours, then 40 ° C, 95% RH.
Size of peeling after leaving for 24 hours under the condition (mm)
Was measured and evaluated according to the following criteria. A: Less than 0 to 0.5 (mm) O: Less than 0.5 to 5.0 (mm) B: Less than 5.0 to 10.0 (mm) X: 10.0 (Mm) or more

Further, the obtained pressure-sensitive adhesive composition has a thickness of 1.1 m.
m on a glass plate using an applicator so that the thickness after drying is 25 μm, and dried at 100 ° C. for 2 minutes to obtain an adhesive plate, while a polyvinyl alcohol polarizing film having a thickness of 30 μm (average degree of polymerization) 1700, average saponification degree 99 mol%, 4 times stretched) A polarizing plate in which cellulose triacetate film having a thickness of 80 μm was laminated on both sides (the stretching axis direction of the polyvinyl alcohol polarizing film was inclined at 45 degrees,
(Cut to 0 mm × 200 mm) was prepared, the above-mentioned adhesive plate was laminated on one side thereof, and pressed with a roller to manufacture a glass laminated polarizing plate. The polarizing plate was subjected to a cycle test and a shock test as described below, and the size (mm) of peeling after the test was measured and evaluated according to the following criteria.

(Cycle test) Polarizing plate at 40 ° C., 95%
After leaving for 60 minutes under RH conditions, after 30 minutes 105
It was left for 60 minutes under the condition of ° C. 30 minutes later 4 again
Exposing under the condition of 0 ° C and 95% RH, the same operation is performed for a total of 1
I went 0 times. (Shock test) The polarizing plate was left under conditions of 0 ° C. for 30 minutes and then immediately under conditions of 100 ° C. for 30 minutes.
After that, expose again to the condition of 0 ° C and perform the same operation in total 1
I went 0 times.

The evaluation criteria are as follows. ◎ ... Peeling is less than 0 to 2 (mm) O ... Peeling is less than 2 to 5 (mm) Δ ... Peeling is less than 5 to 10 (mm) X ... Peeling is 10 (mm) or more The change in optical characteristics after the cycle test and after the shock test was evaluated.

Regarding the optical characteristics of the polarizing plate, the single transmittance τ (%) and the polarization degree V (%) were measured. Here, the degree of polarization in the present invention is represented by [(H ₁₁ −H ₁ ) / (H ₁₁ + H ₁ )] ^1/2 × 100 (%), and H ₁₁ is the superposition of two polarizing film samples. In some cases, the transmittance (%) measured with a spectrophotometer in a state where the polarizing films are superposed so that the orientation directions thereof are the same, H ₁ is a value of the polarizing film when the two samples are superposed. It is the transmittance (%) measured in a state in which the alignment directions are orthogonal to each other and the layers are superposed.

Similarly, a retardation film (average degree of polymerization: 170
0, average saponification degree 97 mol%, 1.1 times stretched polyvinyl alcohol film, film thickness 50 μm), a retardation plate (polyvinyl alcohol) having a 80 μm thick cellulose triacetate film laminated on both sides of the retardation film. 150 mm x 200 with the film stretching axis tilted 45 degrees
(cut to mm) was prepared, the above-mentioned adhesive plate was laminated on one side thereof, and pressed with a roller to manufacture a glass laminated retardation plate. The retardation plate is also subjected to the cycle test and the shock test in the same manner as described above, and the size of peeling (m
m) and changes in optical properties were evaluated.

Regarding the optical characteristics of the retardation plate, the retardation value (RD) was measured. The retardation value (RD) of the retardation film means the main stretching direction (M
It is defined by the product of the refractive index (II _MD- II _TD ) in the direction (D direction) and the direction (TD direction) perpendicular thereto and the thickness (d) of the retardation film, and is a polarizing microscope with a Babinet type compensator (Nikon It was measured by a compensation method using POH-1 type (light source is white light).

Further, an elliptically polarizing plate having a constitution of cellulose triacetate film / polarizing film / cellulose triacetate film / adhesive layer / cellulose triacetate film / retardation film / cellulose triacetate film / adhesive layer A cycle test and a shock test were performed to evaluate the size of peeling (mm).

Regarding the change in optical characteristics, the polarizing plate was evaluated by the difference between the single transmittance τ (%) and the polarization degree V (%) before and after the test, and it is desired that the absolute value is 5% or less.
The retardation plate is evaluated by the difference in RD value before and after the test, and it is desired that the absolute value is 30 nm or less.

Example 2 In Example 1, the composition of the acrylic copolymer was changed to n-butyl acrylate: acrylic acid: hydroxyethyl methacrylate = 95: 3: 2 (weight ratio), and 3-triethoxysilyl was used. Propyl succinic anhydride (trade name: GF-2
0, Wacker-Chemie GmbH) 3-
The same procedure as in Example 1 was carried out except that the methyldiethoxysilylpropyl succinic anhydride was used, and the adhesive strength, cohesive strength and curved surface adhesive strength were evaluated. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Example 3 In Example 1, triethylenediamine was further added to 1.0
The same procedure as in Example 1 was carried out except that parts were added, and the adhesive strength, cohesive strength and curved surface adhesive strength of the obtained pressure-sensitive adhesive composition were evaluated in the same manner as in Example 1. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Example 4 100 parts of a mixture of n-butyl acrylate: acrylic acid = 95: 5 (weight ratio) was mixed with 3-triethoxysilylpropylsuccinic anhydride (trade name: GF-20, Wacker).
(Manufactured by Chemie GmbH) (0.1 part), benzoyl peroxide (0.1 part) as a polymerization initiator was added, and the mixture was polymerized in toluene to obtain a copolymer solution. In the copolymer solution, to 100 parts of the solid content of the copolymer solution, 1.0 part of Coronate L (manufactured by Nippon Polyurethane Co.), which is an isocyanate compound, and 1,8-diazabicyclo-7-undecene were used as a crosslinking agent. 1.0 part was added and mixed well to obtain a pressure-sensitive adhesive composition. With respect to the obtained pressure-sensitive adhesive composition, the adhesive strength, cohesive strength and curved surface adhesive strength were evaluated in the same manner as in Example 1. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Example 5 The same procedure as in Example 1 was carried out except that 1.0 part of N-stearyldiethanolamine was further added, and the obtained adhesive composition was treated in the same manner as in Example 1 with respect to the adhesive force, cohesive force and bending force. The surface adhesive strength was evaluated. The peeling size (mm) of the polarizing plate, the retardation plate and the elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1 was measured by the above method.
And the change in optical properties were evaluated.

Example 6 In Example 1, triethylenediamine was further added to 1.0
Parts and N-stearyldiethanolamine were added in the same manner, and the obtained adhesive composition was evaluated for adhesive force, cohesive force and curved surface adhesive force in the same manner as in Example 1. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Comparative Example 1 In Example 1, 3-triethoxysilylpropyl succinic anhydride (trade name: GF-20, Wacker-C) was used.
The same procedure as in Example 1 was performed except for the addition of hemie GmbH), and the obtained adhesive composition was evaluated for adhesive strength, cohesive strength and curved surface adhesive strength. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Comparative Example 2 The procedure of Example 1 was repeated except that Coronate L (manufactured by Nippon Polyurethane Industry Co., Ltd.) as a crosslinking agent was not added, and the obtained adhesive composition had the same adhesive strength as in Example 1. The cohesive strength and curved surface adhesive strength were evaluated. A polarizing plate obtained by using the adhesive composition in the same manner as in Example 1,
With respect to the retardation plate and the elliptically polarizing plate, the size (mm) of peeling and the change in optical characteristics were evaluated by the above method.

Comparative Example 3 In Example 1, 3-triethoxysilylsuccinic anhydride (trade name: GF-20, Wacker-Chemi) was used.
e GmbH) was replaced by γ-chloropropyltriethoxysilane, and the obtained pressure-sensitive adhesive composition was evaluated for adhesive strength, cohesive strength and curved surface adhesive strength in the same manner as in Example 1. Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method.

Comparative Example 4 The same procedure as in Example 1 was repeated except that 1.0 part of γ-glycidoxypropyltrimethoxysilane was added instead of adding 3-triethoxysilylsuccinic anhydride. The adhesive strength, cohesive strength and curved surface adhesive strength of the adhesive composition were evaluated in the same manner as in Example 1. A polarizing plate obtained by using the adhesive composition in the same manner as in Example 1,
With respect to the retardation plate and the elliptically polarizing plate, the size (mm) of peeling and the change in optical characteristics were evaluated by the above method.

Comparative Example 5 A pressure-sensitive adhesive composition was obtained by adding 1.0 part of trimethoxysilanepropyl isocyanate to 100 parts of the acrylic copolymer of Example 1, and the obtained pressure-sensitive adhesive composition was used in Example 1
The adhesive strength, cohesive strength and curved surface adhesive strength were evaluated in the same manner as in.
Further, with respect to a polarizing plate, a retardation plate and an elliptically polarizing plate obtained by using the pressure-sensitive adhesive composition in the same manner as in Example 1, the peeling size (mm) and the change in optical characteristics were evaluated by the above-mentioned method. The evaluation results of the examples and the comparative examples are collectively shown in Tables 1 to 4.

[0070]

[Table 1] Adhesive properties Adhesive strength Cohesive strength Curved adhesive strength (kg / 25 mm) Example 1 2.0 ○ ◎ 〃 2 1.8 ○ ◎ 〃 3 1.8 ○ ◎ 〃 4 1.9 ○ ◎ 〃 5 2 0.0 ◎ ◎ 〃 6 2.0 ◎ ◎ Comparative Example 1 0.5 × × 〃 2 0.6 × × 〃 3 0.5 × × 〃 4 1.2 △ △ 〃 5 1.0 × ×

[0071]

[Table 2] (Size of peeling) Polarizing plate Phase difference plate Elliptical polarizing plate Cycle Shock cycle Shock cycle After shock test After test After test After test After test After test Example 1 ◎ ◎ ◎ ◎ ◎ ◎ ◎ 〃 2 ◎ ◎ ◎ ◎ ◎ ◎ ◎ 〃 3 ○ ○ ○ ○ ○ ○ 〃 4 ○ ○ ○ ○ ○ ○ 〃 5 ◎ ◎ ◎ ◎ ◎ ◎ ◎ 〃 6 ○ ○ ○ ○ ○ ○ Comparative example 1 × × × × × × 〃 2 × × × × × × 〃 3 × × × × × × 〃 4 × × × × × × 〃 5 × × × × × ×

[0072]

(Table 3) (Optical characteristics) Cycle Cycle Shock Before shock After test After test Before test After test Example 1 Polarizing plate τ 42 41 42 42 V 99.0 99.0 99.0 99.0 Phase difference plate RD 400 395 400 390 〃 2 Polarizer τ 42 41 42 42 42 V 99.0 99.0 99.0 98.0 Phase difference plate RD 400 392 400 390 〃 3 Polarizer τ 42 42 42 41 V 99.0 99.0 99.0 98.0 retardation plate RD 400 390 400 398 〃 4 polarizing plate τ 42 41 41 42 40 V 99.0 99.0 99.0 98.0 retardation plate RD 400 395 400 390 〃 5 polarizing plate τ 42 40 40 42 41 V 99.0 99.0 99.0 99.0 Phase difference plate RD 400 395 400 393 〃 6 Polarizing plate τ 42 40 42 41 41 V 99.0 99.0 99.0 8.0 the retarder RD 400 395 400 394 Note) tau: single axis transmittance (%) V: degree of polarization (%) RD: retardation value (nm)

[0073]

[Table 4] (Optical characteristics) Cycle Cycle Shock Before shock After test Before test After test After test Comparative example 1 Polarizing plate τ-Unmeasurable-Unmeasurable V-〃-〃 Retardation plate RD-〃-〃〃2 Polarizing plate τ − 〃 − 〃 V − 〃 − 〃 Phase difference plate RD − 〃 − 〃 〃 3 Polarizing plate τ − 〃 − 〃 V − 〃 − 〃 Phase difference plate RD − 〃 − 〃 〃 − Polarizing plate τ 〃 − 〃 Retardation plate RD − 〃 − 〃 〃 5 Polarizing plate τ − 〃 − 〃 V − 〃 − 〃 Phase difference plate RD − 〃 − 〃 Note τ: Single transmittance (%) V: Polarization degree (%) RD: Retardation value (nm) In Comparative Examples 1 to 5, the optical properties could not be measured because the peeling after the test was large, so the measured value before the test was not dared to be noted.

[0074]

EFFECT OF THE INVENTION The pressure-sensitive adhesive composition of the present invention shows a small effect of cohesive force and adhesive force with time even under high temperature or high temperature and high humidity, and has an excellent effect on curved surface adhesive force. In adhesion of film and various substrates such as glass, not only is it excellent in durability such as foaming and peeling of the adhesive, but its optical characteristics deteriorate even when left in a high temperature and high humidity environment for a long time. It also has the effect of not doing it.

Claims (9)

[Claims] 1. A pressure-sensitive adhesive comprising an acrylic resin (A) having a functional group capable of reacting with a carboxyl group, an alkoxysilane compound (B) having a carboxyl group, and a crosslinking agent (C). Composition. 2. The pressure-sensitive adhesive composition according to claim 1, further comprising an amine compound (D). 3. The amine compound (D) is triethylenediamine, N, N, N ', N'-tetramethyltrimethylenediamine, methyliminobispropylamine, aminoethylpiperazine, N, N, N', N '. -Tetramethylethylenediamine, hexamethylenetetramine, 2,
4,6-tris (dimethylaminomethyl) phenol,
2-methylimidazole, pyridine, 1-cyanoethyl-2-methylimidazole, 1,8-diazabicyclo-
3. At least one compound selected from 7-undecene, benzyldimethylamine, triethanolamine, benzyltrimethylammonium chloride, tributylamine, and boron trifluoride-dimethylamine complex. Adhesive composition. 4. The content of the alkoxysilane compound (B) having a carboxyl group is 0.0001 to 10 parts by weight with respect to 100 parts by weight of an acrylic resin (A) containing a functional group capable of reacting with a carboxyl group. It exists, The adhesive composition of Claim 1, 2 or 3 characterized by the above-mentioned. 5. An acrylic resin (A) 1 containing a functional group capable of reacting with a carboxyl group in the content of the cross-linking agent (C).
It is 0.01-10 weight part with respect to 00 weight part, The adhesive composition in any one of Claims 1-4 characterized by the above-mentioned. 6. The content of the amine compound (D) is 0.0001 to 10 parts by weight relative to 100 parts by weight of the acrylic resin (A) containing a functional group capable of reacting with a carboxyl group. The pressure-sensitive adhesive composition according to any one of claims 1 to 5. 7. The crosslinking aid (E) further contains at least one compound selected from a polyol compound, a melamine compound and divinylbenzene, according to any one of claims 1 to 6. Adhesive composition. 8. The pressure-sensitive adhesive composition according to claim 1, which is used for bonding a substrate and an optical film. 9. The pressure-sensitive adhesive composition according to claim 8, wherein the optical film is any one of a polarizing film, a retardation film and an elliptically polarizing film.