JPH10130612A - Self-adhesive composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a self-adhesive compsn. which is excellent in self- adhesiveness and cohesive power, esp. in adhesion to an adherend with minute unevenness, and can be used for bonding an optical film to a substrate without degrading the optical properties of the film by compounding an acrylic (co)polymer (AP), a liq. resin (LP) having a specified glass transition point, and an epoxy-reactive silane compd. (ES). SOLUTION: Acrylic (co)polymer AP is obtd. by copolymerizing a monomer mixture contg. an alkyl acrylate as the main monomer and a polar monomer (e.g. acrylic acid) in an amt. of 0.5-20wt.% of the alkyl acrylate. Pref. liq. resin LP has a glass transition point of 0 deg.C or lower and is flowable at 25 deg.C, an example being a rosin-derived liq. resin. 100 pts.wt. (co)polymer AP is compounded with 0.01-100 pts.wt. liq. resin LP and 0.001-10 pts.wt. silane compd. ES.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an acrylic pressure-sensitive adhesive composition, and more particularly, to a pressure-sensitive adhesive composition having excellent adhesion between an optical film such as a polarizing film and a glass substrate.

[0002]

2. Description of the Related Art Generally, conventionally used pressure-sensitive adhesive compositions or applied articles such as pressure-sensitive adhesive tapes and pressure-sensitive adhesive sheets can be adhered to various surfaces of an applied body at room temperature with a pressure of about a finger pressure. Acrylic pressure-sensitive adhesives are often used for bonding optical films such as polarizing films, but the required performance has been improving year by year, and it has excellent durability under high temperature and high humidity conditions. An adhesive is required.

For example, for the purpose of durability and removability under high-temperature and high-humidity conditions, Japanese Patent Application Laid-Open No. Hei 7-331207 discloses a liquid resin having a glass transition temperature of 0 ° C. or less and a fluidity at 25 ° C. Is disclosed in a specific amount.

[0004]

However, such a pressure-sensitive adhesive composition for a liquid crystal element has excellent durability and removability under high-temperature and high-humidity conditions, but has a surface having minute irregularities. Where there is still room for improvement in the adhesion to the adherend, especially in the bonding between an optical film such as a polarizing film and a glass substrate, when the glass surface is poor in smoothness or the surface is provided with irregularities in design. (For example, display frame, character, character,
In the case where a pattern or the like is provided on the glass surface by printing or the like), the adhered surface has a surface roughness of several μm or tens
There is a possibility that the surface becomes rough with minute irregularities having irregularities of height, and the adhesiveness may decrease. According to the study of the present inventor, in the pressure-sensitive adhesive composition for a liquid crystal element, an adherend having severe surface irregularities It has been found that there is still room for improvement in the adhesiveness with respect to.

[0005]

The inventors of the present invention have conducted intensive studies in order to solve the above-mentioned problems. As a result, the acrylic (co) polymer (A) and the liquid resin having a glass transition temperature of 0 ° C. or lower ( The pressure-sensitive adhesive composition comprising B) and a silane compound (C) having a functional group that reacts with an epoxy group has good adhesiveness to an adherend having a surface with minute irregularities as described above. The present invention was found to have good durability.

As described above, the pressure-sensitive adhesive composition of the present invention comprises an acrylic (co) polymer (A), a liquid resin (B) having a glass transition temperature of 0 ° C. or lower, and a silane having a functional group which reacts with an epoxy group. The most characteristic feature is that a compound (C) is compounded. Further, a compound (D) having at least two epoxy groups, an amine compound (excluding silane compounds) (E), a crosslinking aid The effect of the present invention can be more remarkably exhibited by blending the agent (F) and the like, and is particularly useful for bonding an optical film such as a polarizing film to a glass substrate.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described specifically. The acrylic (co) polymer (A) of the present invention is obtained by copolymerizing a polar monomer component with an alkyl acrylate as a main component. Examples of the alkyl acrylate include ethyl acrylate, N-butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, lauryl acrylate, benzyl acrylate, alkyl acrylate having about 2 to 12 carbon atoms such as cyclohexyl acrylate, and n-butyl methacrylate; Examples thereof include alkyl methacrylates having about 4 to 12 carbon atoms of an alkyl group such as isobutyl methacrylate, 2-ethylhexyl methacrylate, lauryl methacrylate, benzyl methacrylate, and cyclohexyl methacrylate, and further include methyl acrylate and methacrylic acid. Methyl, methacryl Ethyl, alkyl methacrylate having 1 to 3 carbon atoms in the alkyl group such as propyl methacrylate, vinyl acetate, acrylonitrile, methacrylonitrile, styrene, and the like. Further, a monomer generally used for the synthesis of an acrylic resin, such as an alkyl acrylate or an alkyl methacrylate in which an alkyl group is substituted with an aromatic ring group, a heterocyclic group, a halogen atom, etc. It can also be used for the synthesis of a system resin.

As the polar monomer, those which function as a cross-linking point or the like are used, and the kind thereof is not particularly limited. Generally, for example, acrylic acid, methacrylic acid, crotonic acid, maleic acid, itacone Carboxyl group-containing monomers such as acids, hydroxyl group-containing monomers such as 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, and 2-hydroxyvinyl ether;
N, N-dimethylaminoethyl acrylate, Nt-
Anomi group-containing monomers such as butylaminoethyl acrylate, amide group-containing monomers such as acrylamide and methacrylamide, methylol group-containing monomers such as N-methylolacrylamide and N-methylolmethacrylamide, glycidyl acrylate, glycidyl methacrylate Epoxy group-containing monomers such as The copolymerization ratio of the polar monomer component is generally 0.5 to 20 parts by weight per 100 parts by weight of the acrylic acid-based alkyl ester component.

In the production of the acrylic (co) polymer (A), a method well known to those skilled in the art, such as radical copolymerization of the above-mentioned acrylic acid alkyl ester and a polar monomer component in an organic solvent, can be used. Can be manufactured.

Examples of the organic solvent used in the 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. And ketones such as methyl ethyl ketone, acetone, methyl isobutyl ketone and cyclohexanone. As the polymerization catalyst used for radical copolymerization, azobisisobutyronitrile, benzoyl peroxide, di-t-
Butyl peroxide, cumene hydroperoxide and the like are mentioned as specific examples. Further, the polymerization conditions are carried out under conditions well known to those skilled in the art.

The liquid resin (B) having a glass transition temperature of 0 ° C. or less is preferably a resin showing fluidity at 25 ° C.,
When the glass transition temperature exceeds 0 ° C, the laminating property at the time of bonding is poorly improved, and the effects of the present invention cannot be obtained. Specific examples of the liquid resin (B) include a rosin liquid resin (rosin ester, modified rosin alcohol, etc.), a terpene liquid resin (terpene resin, a modified terpene resin, etc.), a petroleum liquid resin (aliphatic petroleum resin, etc.). Resin, aromatic petroleum resin, etc.), cumarone / indene liquid resin, styrene liquid resin (styrene resin, styrene-modified terpene resin, etc.), phenol liquid resin (phenol resin, alkylphenol resin, etc.), xylene liquid resin (xylene) Resin, meta-xylene resin, etc.), and one or more of these can be used.

The number average molecular weight of (B) is preferably from 150 to 4,000, more preferably from 150 to 1,000.
Is preferred. If the number average molecular weight is less than 150, poor appearance during durability becomes a problem. Conversely, if the number average molecular weight exceeds 4,000, the ability to follow irregularities decreases, which is not preferable. Further, the viscosity (measured by a B-type viscometer) of the toluene solution having a solid content of 80% (B) is preferably 10,000 cps / 25 ° C. or less, and more preferably 8,000 cps / 25 ° C. or less, and the viscosity is 10,000 cps / If the temperature exceeds 25 ° C., the ability to follow irregularities is undesirably reduced. (B)
Is preferably 0.01 to 100 parts by weight, more preferably 0.1 to 100 parts by weight, particularly preferably 2 to 100 parts by weight, based on 100 parts by weight of the acrylic (co) polymer (A). . When the amount is less than 0.01 part by weight, the effect of the compounding is not obtained. On the other hand, when the amount exceeds 100 parts by weight, the removability is reduced, and it becomes difficult to correct at the time of lamination, or the adhesive remains. Is not preferred.

Further, the silane compound (C) having a functional group which reacts with the epoxy group is not particularly limited, and examples thereof include carboxyl group-containing silane compounds (including those having an acid anhydride structure) and amino groups. -Containing silane-based compounds, hydroxyl-containing silane-based compounds, amide-containing silane-based compounds, mercapto-containing silane-based compounds, etc., among which carboxyl-containing silane-based compounds, especially silane-based compounds having an acid anhydride structure Is most preferred. As such a carboxyl group-containing silane compound, for example, 3-triethoxysilylpropylsuccinic anhydride (trade name: GF-20,
Wacker-Chemie GmbH),
3-triethoxysilylpropyl succinic acid represented by
3-trimethoxysilylpropyl succinic acid (anhydride),
Examples thereof include 3-methyldimethoxysilylpropylsuccinic acid (anhydride), methyldiethoxysilylpropylsuccinic acid (anhydride), and 1-carboxy-3-triethoxysilylpropylsuccinic anhydride represented by the following formula (3).

[0014]

Embedded image

Embedded image

Embedded image Incidentally, the carboxyl group in the present invention includes an acid anhydride structure as described above.

The amino group-containing silane compounds include N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, N-β (aminoethyl) γ-aminopropyltrimethoxysilane, and N-β (aminoethyl )
Examples of hydroxyl group-containing silane compounds such as γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, and the like include γ-hydroxypropyl Amide group-containing silane compounds such as trimethoxysilane include γ-amidopropyltrimethoxysilane, and mercapto group-containing silane compounds include γ-mercaptopropyltrimethoxysilane.

The content of the silane compound (C) having a functional group which reacts with the epoxy group is 0.0 to 100 parts by weight of the acrylic (co) polymer (A).
001 to 10 parts by weight, preferably 0.0005 to 7 parts by weight, more preferably 0.001 to 5 parts by weight. If the content is less than 0.0001 part by weight, it is difficult to obtain the effect of the addition, and if it exceeds 10 parts by weight, the cohesive strength decreases, which is not preferable. Further, in the present invention, if necessary, other silane compounds such as epoxy silane and acrylic silane can be used together with the silane compound (C) having a functional group that reacts with the epoxy group.

In the present invention, the above (A) to (C)
In addition, it is also useful to blend a compound (D) having at least two epoxy groups in terms of improving the adhesion to the substrate. Such a compound (D) includes ethylene glycol diglycidyl ether and polyethylene glycol diglycol. Glycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether,
Neopentyl glycol diglycidyl ether, 1,6
-Hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, diglycidyl adipate, diglycidyl o-phthalate, dibromoneopentyl glycol diglycidyl ether, poly Tetramethylene glycol diglycidyl ether, resorcin diglycidyl ether, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, diglycerol polyglycidyl ether, triglycidyl tris (2-hydroxyethyl)
Isocyanurate, glycerol diglycidyl ether, glycerol triglycidyl ether, N, N,
N ', N'-tetraglycidyl m-xylenediamine,
1,3-bis (N, N-diglycidylaminomethyl) cyclohexane and the like, among which ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and trimethylolpropane triglycidyl ether are preferably used. Preferred are compounds having a hydroxyl group, for example, sorbitol polyglycidyl ether, polyglycerol polyglycidyl ether, diglycerol polyglycidyl ether,
Glycerol diliglycidyl ether or the like is employed.
Among them, glycerol diglycidyl ether is mentioned as the most preferred.

The content of the compound (D) having at least two epoxy groups is 0.0001 with respect to 100 parts by weight of the acrylic (co) polymer (A).
It is desired that the amount be 10 to 10 parts by weight, preferably 0.001 to 10 parts by weight, more preferably 0.001 to 5 parts by weight. If the content is less than 0.0001 part by weight, the effect of the addition cannot be obtained, and if it exceeds 10 parts by weight, the cohesive strength decreases, which is not preferable.

In the present invention, in addition to the above (A) to (C) or (A) to (D), it is preferable to further contain an amine compound (excluding a silane compound) (E). The effects of the invention can be remarkably exhibited. The amine compound (E) is not particularly restricted but includes, for example, 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, benzyltrimethyl Examples include ammonium chloride, tributylamine, and boron trifluoride-dimethylamine complex, among which triethylenediamine, N, N, N ', N'-tetramethyltrimethylenediamine, N, N, N', N'- Particularly preferred are tetramethylethylenediamine and 2-methylimidazole. The content of the amine-based compound (E) is 0.000 to 100 parts by weight of the acrylic (co) polymer (A).
1 to 10 parts by weight, preferably 0.001 to 10 parts by weight,
More preferably, the amount is 0.001 to 5 parts by weight.

In the present invention, in addition to the above (A) to (E), one or more of a polyol compound (however, a polyfunctional epoxy compound), a melamine compound, and divinylbenzene are used as a crosslinking aid (F). It is preferable to contain more than one species. The content is 0.001 to 50 parts by weight, preferably 0.01 to 3 parts by weight in the case of a polyol compound, based on 100 parts by weight of the acrylic (co) polymer (A).
0 parts by weight, 0.001 to 10 in the case of a melamine compound
Parts by weight, preferably 0.001 to 0.5 parts by weight, and in the case of divinylbenzene, 0.0001 to 10 parts by weight, preferably 0.001 to 10 parts by weight. Can demonstrate.

The polyol compound is not particularly limited, and may be polyether polyol, polyester polyol, hydroxyl group-containing polybutadiene polyol,
Acrylic polyols, castor oil derivatives, nitrogen-free polyols such as tall oil derivatives, and the like, among which preferably, trimethylolpropane, 1,4-butanediol, polytetramethylene ether glycol,
Examples thereof include ethylene glycol, propylene glycol, and 3-methylpentane-1,3,5-triol, and preferably include nitrogen-containing polyol compounds represented by the following chemical formulas (4) and (6). Specifically, chemical formula 4 includes triethanolamine, methyldiethanolamine, polyoxyethylene stearylamine, polyoxyethylene laurylamine, preferably methyldiethanolamine and polyoxyethylene stearylamine. Chemical formula 6 includes N, N, N ′. , N'-tetrakis (2-hydroxypropyl) ethylenediamine,
ADEKA QUADROL (Asahi Denka Kogyo Co., Ltd.).

[0022]

Embedded image Here, R and R 'are alkyl groups, R ₁ is hydrogen, an alkyl group, an acyl group, a phenyl group or any of the following 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 both become 0 at the same time.)

Embedded image

[0023]

Embedded image 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
Do not become 0 at the same time. ), P is an integer of 1 or more.

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

[0025]

Embedded image 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 applied to a substrate, bonded to a film or the like, and then irradiated with an electron beam as necessary.
For electron beam irradiation, 0.1 Mrad to 10 Mrad
It is preferable to irradiate the irradiation amount. In the present invention, when the amine compound (E) and the crosslinking aid (F) are used in combination, they exhibit the best adhesive physical properties.

In the present invention, the acrylic (co) polymer (A) as described above, a liquid resin (B) having a glass transition temperature of 0 ° C. or less, and a silane compound having a functional group which reacts with an epoxy group are used. (C) and further a compound (D) having at least two epoxy groups, an amine compound (E), a crosslinking assistant (F) and the like may be contained. There is no particular limitation, and any method can be adopted.

Thus, the pressure-sensitive adhesive composition of the present invention is excellent in tackiness and cohesive force, and also has an excellent effect of adhesion to a rough surface having fine irregularities, which is a feature of the present invention. It is. Regarding the use of such a pressure-sensitive adhesive composition, a solution dissolved in an organic solvent such as toluene, ethyl acetate, methyl ethyl ketone, or acetone is applied to a substrate or a film such as a release film, and then 30 to 170 ° C., preferably 4 to 170 ° C.
It is dried and cured at a drying temperature of 0 to 150 ° C. to obtain its adhesive properties.

The pressure-sensitive adhesive composition comprises a pressure-sensitive adhesive tape,
It is effectively used for various adhesive applications such as adhesive sheets, and is further bonded to various substrates. The base material is not particularly limited, but a metal plate of any material including a stainless steel plate, an aluminum plate, a steel plate, a copper plate, etc., a synthetic resin decorative plate such as a polyethylene plate, a polypropylene plate, a melamine plate, a phenol plate, a plywood, a veneer In addition to a so-called plate-shaped material such as a glass plate, it can be bonded to the surface of a rod-shaped material, pottery or various molded products. After lamination, electron beam irradiation may be performed as described above, if necessary.

Further, the pressure-sensitive adhesive composition of the present invention exhibits a very excellent effect in bonding a substrate, especially a glass substrate, to an optical film. That is, by using the pressure-sensitive adhesive composition, the adhesiveness to the glass substrate having fine irregularities as described above is excellent, and appearance defects such as foaming and peeling of the pressure-sensitive adhesive layer do not occur. An excellent optical laminate 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, and the like. By using the pressure-sensitive adhesive composition of the present invention for bonding these optical films to a glass substrate, an optical film having excellent heat resistance, wet heat resistance, and optical properties. An optical laminate of a film / glass substrate is obtained. In the present invention, an optical film such as a polarizing film, a retardation film, and an elliptically polarizing film is provided with a protective layer. However, unless otherwise specified, the optical film is referred to as an optical film regardless of the presence or absence of the protective layer.

Hereinafter, the optical laminate will be described in detail. In the present invention, for example, a polyvinyl alcohol-based polarizing film as a base material, a polarizing plate provided with a protective layer as necessary, or a polyvinyl alcohol-based or polycarbonate-based retardation film as a base material, which is necessary. The pressure-sensitive adhesive layer and the release film are added to a retardation plate provided with a protective layer, or an elliptically polarizing plate obtained by combining a polarizing film and a retardation film. As a method of adding a pressure-sensitive adhesive layer and a release film, a pressure-sensitive adhesive layer is provided on a release film, and a method of bonding an optical film thereon, or conversely, a pressure-sensitive adhesive layer is provided on an optical film, A method of attaching a release film thereon is usually employed.

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 optical film is bonded to glass or another substrate as a mating substrate. Used for anti-glare or as sunglasses. The optical film having the pressure-sensitive adhesive layer is used for a reflective or transflective liquid crystal display panel by further providing a reflector and / or a translucent layer. This reflector is usually made of aluminum, silver or other foil,
A board is used. Further, as the translucent layer, the reflectance and the transmittance are selected so that the translucent layer can be used for both the reflection type and the transmission type, and the material is appropriately selected.

The retardation film includes, but is not limited to, polyvinyl alcohol, polycarbonate, polyester, polyarylate, polyimide, polyolefin, polystyrene, polysulfone, polyethersulfone, polyvinylidene fluoride / polymethyl methacrylate, and liquid crystal polymer. , Triacetylcellulose-based resin, cyclic polyolefin, saponified ethylene-vinyl acetate copolymer, polyvinyl chloride and the like are used, but polycarbonate and polyvinyl alcohol-based resin films are mainly used. Polyvinyl alcohol-based resins are usually produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. A small amount of unsaturated carboxylic acids (including salts, esters, amides, nitriles, etc.), olefins, vinyl ethers, It may contain a component copolymerizable with vinyl acetate, such as a saturated sulfonate. Also, polyvinyl alcohol was reacted with aldehydes in the presence of an acid,
For example, a so-called polyvinyl acetal resin such as a polybutyral resin and a polyvinyl formal resin and a polyvinyl alcohol derivative may be used. Average polymerization degree is 500 ~
10,000, the degree of saponification is 80-100 mol%,
It is desirable that the film is uniaxially stretched to about 1.01 to 4 times.

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

Examples of the protective layer include conventionally known cellulose acetate films, acrylic films, polyester resin films, polyolefin resin films, polycarbonate films, polyetheretherketone films, and polysulfone films. However, a cellulose acetate film such as a cellulose triacetate film is preferably used. Furthermore, if necessary, an ultraviolet absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound may be added to the resin film.

The optical laminate of the present invention has various layer constitutions without any particular limitation. 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 film) Mold 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 /) Polarized film (/ Protective layer) / Acrylic adhesive layer / (Protective layer /) Retardation film (/ Protective layer) / Adhesive layer of the present invention / Glass (or release film), functional layer / 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), masking 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), (protective layer /)
Retardation film (/ protective layer) / acrylic pressure-sensitive adhesive layer /
(Protective layer /) Polarizing film (/ Protective layer) / Adhesive layer of the present invention / Glass (or release film), Masking 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), (glass or release film /) pressure-sensitive adhesive layer of the present invention / (protective layer /) retardation film (/ protection Layer) / acrylic pressure-sensitive adhesive layer / (protective layer /) polarized film (/ protective layer) / pressure-sensitive adhesive layer of the present invention / glass (or release film).

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

[0039]

The present invention will be specifically described below with reference to examples. In the following, “parts” and “%” are based on weight unless otherwise specified. Example 1 An acrylic copolymer was prepared by polymerizing 100 parts of a blend of n-butyl acrylate: acrylic acid = 95: 5 (weight ratio) in toluene in the presence of 0.3 parts of benzoyl peroxide (polymerization initiator). A solution of the polymer (A) (solid content: 25%) was obtained. Next, a styrene-based liquid resin (B) (“Picolastic A” manufactured by Rika Hercules Co., Ltd.) was added to the solution of the obtained acrylic copolymer (A) based on 100 parts of the solid content of the copolymer solution.
5 ", glass transition temperature -42 ° C, number average molecular weight 250,
80% solids toluene solution viscosity 43 cps / 25 ° C)
10 parts, 3-triethoxysilylpropylsuccinic anhydride (C) (trade name: GF-20, Wacker-Che)
Mie GmbH (1.0 part) was added and mixed well to obtain a pressure-sensitive adhesive composition. About the obtained pressure-sensitive adhesive composition,
The general adhesive strength, the cohesive strength, and the adhesive strength on the fine uneven surface were evaluated. The methods for evaluating the general adhesive force, the cohesive force, and the adhesive force on the fine uneven surface are as described below.

(General Adhesive Strength) After dissolving the above-mentioned pressure-sensitive adhesive composition in toluene, it is applied to a polyethylene terephthalate film and dried at 100 ° C. for 2 minutes (coating thickness after drying 25).
μm), and reciprocated three times with a manual roller according to JIS Z 0237, and pressed against a glass plate (Ra = 0.1 μm or less, size: width 25 mm, length 180 mm). The sample is autoclaved (50 ° C., 15 minutes, 5 kg
/ Cm ² ) and allowed to stand for 12 hours under the conditions of 20 ° C. and 65% RH, followed by a device according to JIS B7721.
The adhesive strength (kg / 25 mm) was measured by a 90 ° pull-off method according to JISZ0237. Pulling speed is 2
It was 00 mm / min.

(Cohesive force) A polyethylene terephthalate film (size:
JIS Z 023 on a glass plate (same as above, size: width 40 mm, length 80 mm)
The sheet was pressed back and forth three times with a manual roller according to 7. The sample is autoclaved (50 ° C., 15 minutes, 5 kg / c
m ² ) and allowed to stand for 12 hours under the conditions of 20 ° C. and 65% RH.
According to 37, the magnitude of the shift after 48 hours at 70 ° C. (m
m) was measured and evaluated according to the following criteria. ◎: less than 0 to 0.5 (mm) ○: 0.5 to less than 5.0 (mm) △: less than 5.0 to 10.0 (mm) ×: 10.0 (Mm) or more

(Adhesive force of micro-irregular surface) Surface roughness is Ra
A PET film coated with the above-mentioned pressure-sensitive adhesive composition is adhered on a glass plate having a thickness of 3.0 μm according to JIS Z 0237, and a peeling force immediately after the sticking (a) and a peeling force after 3 hours at 90 ° C. (B) was measured, and its rate of change (b) / (a) was determined and evaluated according to the following criteria. ◎ ・ ・ ・ (b) / (a) ≧ 1.4 ○ ・ ・ ・ 1.4> (b) / (a) ≧ 1.2 Δ ・ ・ ・ 1.2> (b) / (a) ≧ 1.1 ×... 1.1> (b) / (a)

Further, the obtained pressure-sensitive adhesive composition had a thickness of 1.1 m.
m on a glass plate having a thickness of 25 μm after drying using an applicator, and dried at 100 ° C. for 2 minutes to obtain an adhesive plate. On the other hand, a polyvinyl alcohol polarizing film having a thickness of 30 μm (average degree of polymerization) 1700, an average saponification degree of 99 mol%, stretched 4 times) on both sides of a 80 μm-thick cellulose triacetate film-laminated polarizing plate (the stretching axis direction of the polyvinyl alcohol polarizing film is inclined 45 ° to 15 °).
(Cut to 0 mm × 200 mm), and the adhesive plate was laminated on one surface thereof, and pressed with a roller to produce 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) A polarizing plate was heated at 40 ° C. and 95%
After standing for 60 minutes under RH conditions, 105 minutes after 30 minutes
It was left for 60 minutes under the condition of ° C. 30 minutes later, 4
It was exposed to 0 ° C. and 95% RH, and the same operation was performed for a total of 3 hours.
Performed 0 times. (Shock test) After the polarizing plate was allowed to stand at 0 ° C. for 30 minutes, it was immediately allowed to stand at 100 ° C. for 30 minutes.
Then, it was again exposed to 0 ° C.
Performed 0 times.

The evaluation criteria are as follows.・ ・ ・: Peeling less than 0 to 2 (mm) ○: Peeling less than 2 to 5 (mm) △: Peeling less than 5 to 10 (mm) ×: Peeling of 10 (mm) or more The optical property change after the cycle test and after the shock test was evaluated.

As for the optical characteristics of the polarizing plate, the single transmittance τ (%) and the degree of polarization 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 (%), where H ₁₁ is the superposition of two polarizing film samples. during, transmittance orientation direction was measured using a spectrophotometer in a state superimposed to have the same direction of the polarizing film (%), H ₁ at the time of superposition of two samples, the polarizing film It is a transmittance (%) measured in a state where the alignment directions are superposed so as to be orthogonal to each other.

Similarly, a retardation film (average degree of polymerization: 170
0, an average saponification degree of 97 mol%, a 1.1-fold stretched polyvinyl alcohol film, and a film thickness of 50 μm), a retardation plate (polyvinyl alcohol film) having an 80 μm-thick cellulose triacetate film laminated on both sides of the retardation film. Tilt the stretching axis direction of the film by 45 degrees, 150mm x 200
mm), the adhesive plate was laminated on one surface thereof, and pressed with a roller to produce a glass laminated retardation plate. A cycle test and a shock test were performed on the retardation plate in the same manner as described above, and the magnitude of the peeling after the test (m
m) and changes in optical properties were evaluated.

The retardation value (RD) was measured for the optical characteristics of the retardation plate. The retardation value (RD) of the retardation film refers to the main stretching direction (M
D) and the refractive index (II _MD -II _TD ) in the direction perpendicular thereto (TD direction) and the thickness (d) of the retardation film, and are defined by a polarizing microscope (Nikon with a Babinet type compensator). (POH-1 type) was measured by a compensation method (the light source was 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 is also used. A cycle test and a shock test were performed to evaluate the size (mm) of peeling.

The change in the optical characteristics of the polarizing plate is evaluated by the difference between the single transmittance τ (%) and the degree of polarization V (%) before and after the test, and is desirably 5% or less in absolute value.
The retardation plate is evaluated based on the difference between the RD values before and after the test, and is desirably 30 nm or less in absolute value.

Example 2 A pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that 1.0 part of glycerol diglycidyl ether (D) was further added to the pressure-sensitive adhesive composition of Example 1, and evaluation was similarly performed. Was.

Example 3 In Example 1, a xylene liquid resin (Modified xylene formaldehyde resin "Nicanol" manufactured by Mitsubishi Gas Chemical Co., Ltd., glass transition temperature -31 ° C., number average molecular weight 400, solid content 80) was used as the component (B). % Toluene solution viscosity 73c
(ps / 25 ° C.) except that 10 parts were used to obtain a pressure-sensitive adhesive composition, which was similarly evaluated.

Example 4 In Example 1, a rosin-based liquid resin (rosin alcohol resin “Abitol” manufactured by Rika Hercules Co., Ltd.) having a glass transition temperature of −20 ° C. and a number average molecular weight of 27 was used as the component (B).
5. Viscosity of toluene solution with a solid content of 80% 116 cps / 2
(5 ° C.) except that 10 parts were used to obtain a pressure-sensitive adhesive composition, which was similarly evaluated.

Example 5 Example 2 was repeated except that 1.0 part of polyoxyethylene stearylamine (F) was further added.
An adhesive composition was obtained and evaluated in the same manner.

Example 6 An adhesive composition was prepared in the same manner as in Example 2 except that 1.0 part of triethylenediamine (E) and 1.0 part of polyoxyethylene stearylamine (F) were further added. Obtained and evaluated similarly.

Comparative Example 1 A pressure-sensitive adhesive composition was obtained in the same manner as in Example 1 except that the styrene liquid resin (B) was not added.
Evaluation was performed similarly. Comparative Example 2 In Example 1, 3-triethoxysilylpropyl succinic anhydride (C) (trade name: GF-20, Wacker)
An adhesive composition was obtained in the same manner except that r-Chemie GmbH (manufactured by r-Chemie GmbH) was not added, and evaluated in the same manner. Table 1 shows the evaluation results of the examples and the comparative examples.
To 4 collectively.

[0057]

[Table 1] Adhesive properties General adhesive force Cohesive force Adhesive force on micro uneven surface (kg / 25 mm) Example 1 1.8 ○ 〃 2 1.9 ◎ ３ 3 1.8 ○ ○ 4 1.9 ◎ ○ ５ 5 1.8 ◎ ○ ６ 6 2.0 ◎ ◎ Comparative Example 1 1.0 ○ × 〃 21.0 ○ ×

[0058]

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

[0059]

Table 3 (Change in optical properties) Cycle Cycle Shock Before test After test Before test Before test After test Example 1 Polarizing plate τ 42 41 42 42 V 99.0 99.0 99.0 99.0 Retardation plate RD 400 395 400 390 〃2 polarizing plate τ 42 40 42 40 V 99.0 99.0 99.0 98.0 Retardation plate RD 400 395 400 393 ３3 polarizing plate τ 42 40 42 42V 99.0 99.0 99. 0 98.0 Retardation plate RD 400 392 400 389 〃4 Polarizing plate τ 42 42 42 41 V 99.0 99.0 99.0 98.0 Retardation plate RD 400 394 400 393 ５5 Polarizing plate τ 42 39 42 40 V 99.0 99.0 99.0 99.0 Retardation plate RD 400 395 400 392 〃6 Polarizer τ 42 41 42 42 V 99.0 99.0 99. 0 98.0 retardation plate RD 400 392 400 391 Note) τ: Single transmittance (%), V: Degree of polarization (%), RD: Retardation value (nm)

[0060]

(Change in optical characteristics) Cycle Cycle Shock Before test After test Before test Before test After test Comparative Example 1 Polarizing plate τ 42 41 42 41 V 99.0 99.0 99.0 99.0 Retardation plate RD 400 395 400 390 〃 2 Polarizing plate τ 42 40 42 41 V 99.0 99.0 99.0 98.0 Retardation plate RD 400 394 400 393 Note) τ: Single transmittance (%), V: Degree of polarization (%) , RD: retardation value (nm)

[0061]

Since the pressure-sensitive adhesive composition of the present invention contains a liquid resin having a glass transition temperature of 0 ° C. or less and a silane compound having a functional group which reacts with an epoxy group, the pressure-sensitive adhesive and cohesive strength are reduced. Excellent and has excellent adhesion to the adherend on the surface with fine irregularities.Especially when used for bonding optical film and base material, it does not cause foaming or peeling of the adhesive and its optical properties even after long use. The effect that the characteristics do not decrease is also exhibited. Utilizing such characteristics, it is used for a liquid crystal display, and is particularly useful for a vehicle, various industrial instruments, display of household electric appliances, and the like.

[Procedure amendment]

[Submission date] January 12, 1998

[Procedure amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0039

[Correction method] Change

[Correction contents]

[0039]

The present invention will be specifically described below with reference to examples. In the following, “parts” and “%” are based on weight unless otherwise specified. Example 1 An acrylic copolymer was prepared by polymerizing 100 parts of a blend of n-butyl acrylate: acrylic acid = 95: 5 (weight ratio) in toluene in the presence of 0.3 parts of benzoyl peroxide (polymerization initiator). A solution of the polymer (A) (solid content: 25%) was obtained. Next, a styrene-based liquid resin (B) (“Picolastic A” manufactured by Rika Hercules Co., Ltd.) was added to the solution of the obtained acrylic copolymer (A) based on 100 parts of the solid content of the copolymer solution.
5 ", glass transition temperature -42 ° C, number average molecular weight 250,
80% solids toluene solution viscosity 43 cps / 25 ° C)
10 parts, 3-triethoxysilylpropylsuccinic anhydride (C) (trade name: GF-20, Wacker-Che)
Mie GmbH) 1.0 part and Coronate L (Japan
1.0 part of Polyurethane Co.) was added and mixed well to obtain a pressure-sensitive adhesive composition. With respect to the obtained pressure-sensitive adhesive composition, general adhesive strength, cohesive strength, and adhesive strength on a fine uneven surface were evaluated. The methods for evaluating the general adhesive force, the cohesive force, and the adhesive force on the fine uneven surface are as described below.

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Claims (12)

[Claims] An acrylic (co) polymer (A), a liquid resin (B) having a glass transition temperature of 0 ° C. or lower, and a silane compound (C) having a functional group which reacts with an epoxy group. A pressure-sensitive adhesive composition comprising: 2. The pressure-sensitive adhesive composition according to claim 1, wherein the functional group that reacts with the epoxy group is any one of a carboxyl group, an amino group, a hydroxyl group, and an amide group. 3. The content of the silane compound (C) having a functional group that reacts with an epoxy group is 0.0001 to 10 parts by weight based on 100 parts by weight of the acrylic (co) polymer (A). The pressure-sensitive adhesive composition according to claim 1 or 2, wherein 4. A liquid resin (B) having a glass transition temperature of 0 ° C. or lower is a rosin liquid resin, a terpene liquid resin, a petroleum liquid resin, a cumarone / indene liquid resin, a styrene liquid resin, or a phenol liquid resin. The pressure-sensitive adhesive composition according to any one of claims 1 to 3, wherein the pressure-sensitive adhesive composition is at least one member selected from the group consisting of a xylene liquid resin. 5. The pressure-sensitive adhesive composition according to claim 1, further comprising a compound (D) having at least two epoxy groups. 6. The pressure-sensitive adhesive composition according to claim 5, wherein the compound (D) having at least two epoxy groups is a compound also having a hydroxyl group. 7. The content of the compound (D) having at least two epoxy groups is 0.0001 to 10 parts by weight based on 100 parts by weight of the acrylic (co) polymer (A). The pressure-sensitive adhesive composition according to claim 5 or 6, wherein 8. The pressure-sensitive adhesive composition according to claim 1, further comprising an amine compound (excluding a silane compound) (E). 9. An amine compound (E) comprising 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-
The pressure-sensitive adhesive composition according to claim 8, wherein the pressure-sensitive adhesive composition is at least one selected from 7-undecene, benzyldimethylamine, triethanolamine, benzyltrimethylammonium chloride, tributylamine, and boron trifluoride-dimethylamine complex. . 10. The composition according to claim 1, further comprising at least one compound selected from the group consisting of a polyol compound (excluding a polyfunctional epoxy compound), a melamine compound, and divinylbenzene as the crosslinking assistant (F). 1-9
The pressure-sensitive adhesive composition according to any one of the above. 11. The pressure-sensitive adhesive composition according to claim 1, which is used for bonding a substrate and an optical film. 12. The pressure-sensitive adhesive composition according to claim 11, wherein the optical film is any one of a polarizing film, a retardation film, and an elliptically polarizing film.