TWI475084B - Adhesive composition and optical film - Google Patents

Description

Adhesive composition and optical film

The present invention relates to an adhesive composition for an optical film, and an optical film to which the adhesive is applied, which is used for adhering an optical film such as a polarizing film or a retardation film to an adherend such as a liquid crystal cell. More specifically, the present invention relates to an adhesive composition for an optical film and an optical film to which the adhesive is attached, the adhesive composition having the following characteristics: if the optical film is stuck to the adherend, if it occurs It is also capable of being peeled off, has excellent durability under high temperature and high humidity, and is difficult to produce white defects.

A liquid crystal display device which is used in a wide range of fields as a display device is usually a liquid crystal cell having a liquid crystal component aligned in a predetermined direction between two supporting substrates such as glass, and a polarizing film, a retardation film, and a brightness enhancement film. An optical film is used, and an adhesive is often used when the laminated optical films are adhered to each other or to the liquid crystal cells.

As a display device of a personal computer, a television, a satellite navigation system, etc., a liquid crystal display device is used in a wide range. What follows is the requirement for an adhesive that is excellent in durability even in such harsh environments under high temperature and high humidity, that is, it does not peel off or bubble even for long-term use. Produce and so on. Moreover, in such a harsh environment under high temperature and high humidity, the optical film has a large dimensional change such as shrinkage and expansion. When the adhesive layer cannot alleviate the stress due to the dimensional change, the residual stress of the optical film becomes uneven. As a result, light leaks from the peripheral portion of the liquid crystal display device and becomes white, which is a problem of so-called "white defects".

Further, in the technical field of the present invention, when an optical film having such an adhesive layer is adhered to an adherend, and a foreign matter or the like is stuck or displaced, a redo is performed. The operation removes and removes the optical film from the adherend and reattaches the new optical film. At this time, if the adhesive strength of the optical film is large, it is difficult for the optical film to be peeled off from the adherend, or a part of the adhesive remains on the adherend after peeling off the optical film.

In this way, the adhesive used for the optical film is required to have durability, that is, it must be adhered to an adherend such as a liquid crystal cell, and the use of high temperature and high humidity does not cause peeling or bubbles. On the other hand, the adhesive is also required to have a characteristic that it is easy to peel off from the adherend during the redo work and a part of it does not remain on the adherend (hereinafter referred to as "reworkability"). As such, what is sought is an adhesive which can simultaneously have durability and reworkability opposite to each other, and at the same time, white defects are hard to occur.

In order to solve the above problems, various discussions have been made. For example, Japanese Patent Publication No. Hei 10-279907 discloses a combination of a high molecular weight acrylic copolymer and a low molecular weight acrylic copolymer having a weight average molecular weight of 30,000 or less, which has durability and white defects. However, there is no repetitive description, and it is fully expected that the adherend will be contaminated due to leakage of the low molecular weight copolymer component, and the reworkability will be poor.

Further, Japanese Laid-Open Patent Publication No. 2006-235568 discloses an adhesive which is excellent in durability and hard to produce white defects even under high temperature and high humidity by using an active energy ray-curable adhesive composition. Characteristics, but there is no description about redo. When the inventors of the present invention tried to repeat the examples described in the above-mentioned publications, the obtained adhesive was excellent in durability and white defects, but the adhesiveness at 50 ° C and 24 hours after the reworkability index was high. , bad redo.

[Patent Document 1] Japanese Patent Laid-Open No. Hei 10-279907

[Patent Document 2] Japanese Patent Laid-Open Publication No. 2006-235568

An object of the present invention is to provide an adhesive for an optical film and an optical film which has excellent durability and can suppress white defects even in a high-temperature and high-humidity environment, and can be used in the case where an optical film is required to be reattached. Easy to redo.

In order to solve the above problems, the inventors of the present invention have found that the above problems can be solved by using an ultraviolet curable adhesive having a specific acrylic resin composition and using a decane coupling agent having a specific structure, and completed the present invention. That is, the present invention is constituted by the following configuration in order to solve the above problems.

An adhesive composition comprising: an acrylic copolymer (A); and 100 parts by weight of the acrylic copolymer (A)

1 to 30 parts by weight of the polyvinyl monomer (B),

0.01 to 5 parts by weight of the crosslinking agent (C), and

0.01 to 1 part by weight of tris(3-trialkoxysilylalkyl isocyanurate) (D).

2. The adhesive composition according to the above 1, which further contains 0.001 to 0.2 part by weight of the epoxy-based decane coupling agent (E) based on 100 parts by weight of the acrylic copolymer (A).

3. The adhesive composition according to the above 1, wherein the acrylic copolymer (A) contains 0.1 to 10% by weight of a hydroxyl group-containing monomer and 0.1 to 3% by weight of a carboxyl group-containing monomer as a total of Polymerized ingredients, and

The value of (% by weight of the hydroxyl group-containing monomer contained in the acrylic copolymer (A)) divided by (% by weight of the carboxyl group-containing monomer contained in the acrylic copolymer (A)) is 0.1 to 30.

An optical film having an adhesive layer formed of an adhesive composition comprising: an acrylic copolymer (A); and 100 parts by weight of the acrylic copolymer (A) for

1 to 30 parts by weight of the polyvinyl monomer (B),

0.01 to 5 parts by weight of the crosslinking agent (C), and

0.01 to 1 part by weight of tris(3-trialkoxydecylalkyl) isocyanurate (D).

5. The optical film according to the above-mentioned item 4, which further contains 0.001 to 0.2 part by weight of the epoxy-based decane coupling agent (E) based on 100 parts by weight of the acrylic copolymer (A).

6. The optical film according to the above item 4, wherein the acrylic copolymer (A) contains 0.1 to 10% by weight of a hydroxyl group-containing monomer and 0.1 to 3% by weight of a carboxyl group-containing monomer as a copolymerization component. ,and

The value of (% by weight of the hydroxyl group-containing monomer contained in the acrylic copolymer (A)) divided by (% by weight of the carboxyl group-containing monomer contained in the acrylic copolymer (A)) is 0.1 to 30.

7. The optical film according to the above 6, wherein after the adhesive layer is formed, the adhesion to the alkali-free glass plate after the lapse of 24 hours at 50 ° C is 0.5 to 10 N / 25 mm, after 24 hours at 80 ° C for The adhesion of the alkali-free glass plate and the adhesion to the alkali-free glass plate after 24 hours at 60 ° C and 90% RH (relative humidity) are 10 N/25 mm or more.

According to the optical film adhesive and optical film of the present invention, an adhesive for an optical film and an optical film can be provided, and the adhesive has excellent durability and can suppress white defects even in a high-temperature and high-humidity environment. At the same time, it is easy to redo when it is required to reattach the optical film.

[Preferred form of implementing the invention]

The adhesive composition according to the embodiment of the present invention contains an acrylic copolymer (A), a polyethylenic monomer (B), a crosslinking agent (C), and tris 3-trialkyloxy isocyanate. Mercaptoalkyl)ester (D). The adhesive composition of the present embodiment is photopolymerized by ultraviolet irradiation of the polyethylenic monomer (B) dispersed in the acrylic copolymer (A) to form a three-dimensional structure, and further, an acrylic copolymer. The crosslinking group in (A) and the crosslinking agent (C) undergo a crosslinking reaction to form an adhesive having good adhesion characteristics.

In the present embodiment, the acrylic copolymer (A) is an acrylate monomer or a methacrylate monomer containing 80% by weight or more of the copolymer (hereinafter, the vocabulary containing "acrylic acid" is collectively described. In the case of the word "methacrylic acid", it is referred to as "(meth)acrylic acid), and the copolymer which is a copolymerization component is preferably a copolymerized product containing 90% by weight or more.

The (meth) acrylate monomer is not particularly limited as long as it has a (meth) acrylate structure, and for example, methyl (meth) acrylate or ethyl (meth) acrylate can be used. Base) n-butyl acrylate, isobutyl (meth)acrylate, n-octyl (meth)acrylate, isooctyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (methyl) N-decyl acrylate, isodecyl (meth) acrylate, n-decyl (meth) acrylate, n-dodecyl (meth) acrylate, octadecyl (meth) acrylate, etc. (methyl) The linear or branched alkyl ester having 1 to 18 carbon atoms of the acrylic acid may be used, and one or more of various derivatives of these alkyl esters may be used.

The acrylic copolymer (A) may contain a monomer other than the (meth) acrylate monomer as a copolymerization component within a range not exceeding the definition of the acrylic copolymer (A). As the monomer other than the (meth) acrylate monomer, for example, a saturated fatty acid vinyl ester, an aromatic vinyl monomer, a vinyl cyanide monomer, a maleic acid or a fumaric acid can be used. Diester. For example, as the saturated fatty acid vinyl ester, vinyl formate, vinyl acetate, vinyl propionate, "vinyl versatate" (trade name), etc. (preferably vinyl acetate); aromatic Ethylene monomer such as styrene, α-methylstyrene, vinyl toluene, etc.; vinyl cyanide monomer such as acrylonitrile, methacrylonitrile; maleic acid or diester of fumaric acid, for example Dimethyl maleate, di-N-butyl maleate, di-2-ethylhexyl maleate, di-N-octyl maleate, fubutene Dimethyl dicarboxylate, di-N-butyl fumarate, di-2-ethylhexyl fumarate, di-N-octyl fumarate, and the like.

In the acrylic copolymer (A), a monomer having a functional group is used as a copolymer in the acrylic copolymer (A) for the purpose of reacting the acrylic copolymer (A) and the crosslinking agent (C). The composition is preferred. In addition, the monomer (meth) acrylate having a functional group is also calculated as a (meth) acrylate monomer which is contained in the acrylic polymer (A) as a copolymerization component when the acrylic copolymer is defined. the amount.

As the monomer having a functional group, for example, a carboxyl group-containing monomer, a hydroxyl group-containing monomer, a glycidyl group-containing monomer, a guanamine-containing monomer, an N-substituted guanamine-based monomer, and a tertiary amino group-containing group can be used. One type or two or more types of monomers.

As the hydroxyl group-containing monomer, for example, 2-hydroxyethyl (meth)acrylate, 2-hydroxypropyl (meth)acrylate, 3-hydroxypropyl (meth)acrylate, or (meth)acrylic acid 4- can be used. Hydroxybutyl ester, 3-methyl-3-hydroxybutyl (meth)acrylate, 1,1-dimethyl-3-butyl (meth)acrylate, 1,3-dimethyl (meth)acrylate -3-hydroxybutyl ester, 2,2,4-trimethyl-3-hydroxypentyl (meth)acrylate, 2-ethyl 3-hydroxyhexyl (meth)acrylate, glycerol mono(meth)acrylate Ester, polypropylene glycol mono (meth) acrylate, polyethylene glycol mono (meth) acrylate, poly (ethylene glycol propylene glycol) mono (meth) acrylate, N-methylol acrylamide, olefin Propanol, methyl allyl alcohol, and the like.

As the carboxyl group-containing monomer, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid, citraconic acid, cinnamic acid, amber can be used. Acid monohydroxyethyl (meth) acrylate, maleic acid monohydroxyethyl (meth) acrylate, fumaric acid monohydroxy ethyl (meth) acrylate, phthalic acid monohydroxyl Ethyl (meth) acrylate, 1,2-dicarboxycyclohexane monohydroxyethyl (meth) acrylate, (meth) acrylate dimer, ω-carboxy-polycaprolactone mono (methyl ) Acrylate and the like.

As the glycidyl group-containing monomer, for example, glycidyl (meth)acrylate, 3,4-epoxycyclohexylmethyl methacrylate, glycidyl vinyl ether, 3,4-epoxycyclohexyl group can be used. Vinyl ether, glycidyl (meth)acrylate, 3,4-epoxycyclohexyl (meth)acrylate, and the like.

As the guanamine-containing monomer and the N-substituted guanamine-based monomer, for example, acrylamide, methacrylamide, N-methyl(meth) acrylamide, N-ethyl (A) can be used. Base acrylamide, N-methoxymethyl (meth) acrylamide, N-ethoxymethyl (meth) acrylamide, N-propoxymethyl (meth) acrylamide N-butoxymethyl (meth) acrylamide, N-butyl butyl decylamine, N-octyl acrylamide, diacetone acrylamide, and the like.

As the tertiary amino group-containing monomer, dimethylaminoethyl (meth)acrylate, diethylamine ethyl (meth)acrylate, dimethylaminopropyl (meth)acrylate, or the like can be used.

Among the monomers having various functional groups as the copolymer component, those contained in the acrylic copolymer (A) as a copolymer component are particularly preferably a hydroxyl group-containing monomer and a carboxyl group-containing monomer.

The ratio of the hydroxyl group-containing monomer contained as a copolymer component is 0.1% by weight or more based on the acrylic copolymer (A) for the purpose of increasing the cohesive force of the pressure-sensitive adhesive and improving the durability of the adhesive composition. It is preferably 1% by weight or more. In addition, the ratio of the hydroxyl group-containing monomer contained as a copolymer component is based on the reduction of the adhesive force of the adhesive composition and the durability of the adhesive composition to be practically applied to the acrylic copolymer (A). It is preferably 10% by weight or less and preferably 5% by weight or less.

The ratio of the carboxyl group-containing monomer contained as a copolymer component is 0.1% by weight or more based on the acrylic copolymer (A) for the purpose of increasing the cohesive force of the pressure-sensitive adhesive and improving the durability of the adhesive composition. It is preferably 0.2% by weight or more, particularly preferably 0.5% by weight or more. In addition, the ratio of the carboxyl group-containing monomer to be contained as a copolymer component is 3% by weight or less based on the acrylic copolymer (A), for the purpose of suppressing the adhesive force of the adhesive composition. It is preferably 2% by weight or less, particularly preferably 1% by weight or less.

The ratio of the hydroxyl group-containing monomer to the carboxyl group-containing monomer contained in the acrylic copolymer (A) is preferably (acrylic copolymer (A) for the purpose of coexisting durability and reworkability of the adhesive composition. The value by weight of the hydroxyl group-containing monomer contained in the (% by weight of the carboxyl group-containing monomer contained in the acrylic copolymer (A)) is 0.1 to 30.

The weight average molecular weight (Mw) of the acrylic copolymer (A) is preferably 800,000 or more, preferably 1,000,000 or more, for the purpose of imparting sufficient cohesive force to the adhesive composition and suppressing generation of bubbles. In addition, the weight average molecular weight (Mw) of the acrylic copolymer (A) is preferably 2.5 million or less, and preferably 1.8 million or less, for the purpose of ensuring the coating workability of the adhesive composition.

The weight average molecular weight (Mw) of the acrylic copolymer (A) is a value measured by the following method.

(Method for measuring weight average molecular weight (Mw))

The measurement was carried out in accordance with the following (1) to (3).

(1) The acrylic copolymer (A) solution was applied onto a release paper, and dried at 100 ° C for 2 minutes to obtain a film-form acrylic copolymer (A).

(2) The film-form acrylic copolymer (A) obtained in the above (A) was dissolved in tetrahydrofuran to have a solid content of 0.2%.

(3) The weight average molecular weight (Mw) of the acrylic copolymer (A) was measured by gel permeation chromatography (GPC, Gel permeation chromatography) under the following conditions.

(condition)

GPC: HLC-8220 GPC [made by Japan Tosoh Co., Ltd.]

Column: Use 4 TSK-GEL GMHXL

Mobile phase solvent: tetrahydrofuran

Flow rate: 0.6ml/min column temperature: 40°C

The glass transition temperature (Tg) of the acrylic copolymer (A) is preferably -80 ° C or more, and preferably -60 ° C or more, for the purpose of imparting sufficient cohesive force to the adhesive composition to exhibit sufficient durability. In addition, the glass transition temperature (Tg) of the acrylic copolymer (A) is -20 ° C or less for the purpose of imparting sufficient adhesion to the support substrate and durability against peeling or the like. It is preferably -30 ° C or less. Further, in the present embodiment, the glass transition temperature (Tg) of the acrylic copolymer (A) is a value measured by the following method.

(Method for measuring glass transition temperature (Tg))

The measurement was carried out in accordance with the following (1) to (3).

(1) The acrylic copolymer (A) solution was applied onto a release paper, and dried at 100 ° C for 2 minutes to obtain a film-form acrylic copolymer (A).

(2) A sample obtained by the above (1) weighing about 10 mg was filled in a cylindrical cell composed of an aluminum foil having a thickness of about 0.05 mm and having an inner diameter of about 5 mm and a depth of about 5 mm, and this was used as a measurement sample.

(3) The measurement was carried out at a temperature increase rate of 10 ° C/min from -150 ° C using a SSC-5000 differential scanning calorimeter manufactured by Seiko Instruments Inc., Japan.

The polymerization method of the acrylic copolymer (A) used in the present embodiment is not particularly limited, and it can be polymerized by a method such as solution polymerization, emulsion polymerization or suspension polymerization. Further, when the adhesive composition of the present embodiment is produced by using a mixture of copolymers obtained by polymerization, the polymerization is carried out by a solution polymerization in which the treatment step is relatively simple and the adhesive composition can be obtained in a short time. good.

The solution polymerization may be carried out by adding a predetermined organic solvent, a monomer, a polymerization initiator, and a chain transfer agent as needed, to a polymerization tank, and stirring while stirring in a nitrogen gas stream or an organic solvent. The heating reaction is carried out for several hours. Further, the molecular weight of the acrylic copolymer (A) of the present embodiment can be adjusted to a desired molecular weight by adjusting the reaction temperature, time, amount of solvent, and type or amount of the catalyst.

The adhesive composition of the present embodiment contains the polyethylenic monomer (B) in an amount of 1 to 30 parts by weight based on 100 parts by weight of the acrylic copolymer (A), except for the acrylic copolymer (A). In addition to the crosslinking reaction of the crosslinking group and the crosslinking agent (C), a multi-vinyl monomer is photopolymerized by ultraviolet (UV) irradiation to form a three-dimensional structure. Thereby, an adhesive having high cohesive force can be obtained. Further, in the present embodiment, the polytetraethylene monomer (B) means a monomer having a plurality of radically bonded ethylene bonds.

Specific examples of the polyvinyl monomer (B) include, for example, ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylic acid. Ester, neopentyl glycol di(meth)acrylate, 1,6-hexanediol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, pentaerythritol tri(meth)acrylate Dipentaerythritol hexa(meth) acrylate, divinyl benzene, N, N'-methylene bis acrylamide, and the like.

The amount of the polyethylenic monomer (B) used per 100 parts by weight of the acrylic copolymer (A) is 1 part by weight or more, for the purpose of suppressing white defects of the adhesive composition and exhibiting sufficient durability. It is preferably 10 parts by weight or more. In addition, the amount of the polyethylenic monomer (B) used per 100 parts by weight of the acrylic copolymer (A) is 30 parts by weight or less, for the purpose of suppressing the occurrence of the peeling in the durability test and the reduction of the adhesive force. It is preferably 20 parts by weight or less.

The adhesive composition of the present embodiment preferably contains a polyvinyl monomer (B) and a photopolymerization initiator. As the photopolymerization initiator, a substance which generates a radical by irradiation with ultraviolet rays having an appropriate wavelength capable of triggering a polymerization reaction can be used.

As the photopolymerization initiator, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, o-benzoin benzoic acid methyl-p-benzoin ethyl ether, benzoin isopropyl ether, α-methylbenzoin, etc. benzoin; Acetophenones such as benzil dimethyl ketal, trichloroacetophenone, 2,2-diethoxyacetophenone, 1-hydroxycyclohexylacetophenone; 2-hydroxy-2-methylpropiophenone , phenylacetone such as 2-hydroxy-4'-isopropyl-2-methylpropiophenone; diphenyl ketone, methyl diphenyl ketone, p-chlorodiphenyl ketone, p-dimethylamino benzene Diphenyl ketones such as ketones; thioxanthones such as 2-chlorothioxanthone, 2-ethylthioxanthone, 2-isopropylthioxanthone; oxidized bis(2,4,6-trimethyl) Benzyl hydrazino)-phenylphosphine, 2,4,6-trimethylbenzhydryldiphenylphosphine oxide, (2,4,6-trimethylbenzylidene)-(ethoxy) a mercaptophosphine oxide such as phenylphosphine; diphenylethylenedione, dibenzocycloheptanone, α-acyloxime ester, and the like. These compounds may be used singly or in combination of two or more kinds of compounds.

The photopolymerization initiator is used in an amount of 0.01 part by weight or more based on 100 parts by weight of the acrylic copolymer (A) for the purpose of suppressing white defects of the adhesive composition to exhibit sufficient durability. The above is better. In addition, the use amount of the photopolymerization initiator of 100 parts by weight of the acrylic copolymer (A) is 5.0 parts by weight or less, based on the purpose of suppressing the occurrence of peeling in the durability test and the reduction of the adhesive strength, to 2.0 parts by weight. The following are preferred.

The adhesive composition of the present embodiment is formed by containing 0.01 to 5 parts by weight of a crosslinking agent (C) per 100 parts by weight of the acrylic copolymer (A), and the crosslinking agent (C) contains 2 More than one functional group capable of reacting with the acrylic copolymer (A) to form a crosslinked structure preferably contains 2 to 4 functional groups.

The crosslinking agent (C) is not particularly limited as long as it can react with the acrylic copolymer (A) to form a crosslinked structure. For example, as the crosslinking agent (C), a polyisocyanate compound, a polyaziridine compound, a polyepoxy compound, a melamine formaldehyde condensate, a metal salt, a metal chelate compound, or the like can be used. Moreover, from the viewpoints of the adhesion between the optical film and the adhesive composition, the stability after blending the acrylic copolymer (A), etc., it is preferred to use a polyisocyanate compound, a polyaziridine compound, and/or Or polyepoxide. These crosslinking agents (C) can be used individually or in combination of 2 or more types.

As the polyisocyanate compound, for example, an aromatic polyisocyanate such as benzodimethyl diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate or toluene diisocyanate can be used. Further, as the polyisocyanate compound, for example, an aliphatic or alicyclic polyisocyanate such as hexamethylene diisocyanate, isophorone diisocyanate or a hydrogenated product of an aromatic polyisocyanate compound can be used. Further, various polyisocyanate compounds derived from polyisocyanates such as a dimer or a trimer of the polyisocyanate or an adduct of a polyhydric alcohol such as a polyisocyanate or trimethylolpropane may be used.

As the polyisocyanate compound, for example, a polyisocyanate compound which is commercially available under the trade names of "Coronate L", "Coronate HX", "Coronate HL-S", and "Coronate 2234" can be used. Company system]; "Desmodur N3400" [made by Japan Sumitomo Bayer Polyurethane Co., Ltd.], "DURANATE E-405-80T", "DURANATE TSE-100" [made by Asahi Kasei Industrial Co., Ltd.], "Takenate D-110N" "Takenate D-120N" and "Takenate M-631N" [above, manufactured by Mitsui Takeda Chemical Co., Ltd., Japan].

As the polyaziridine compound, a reaction product of a polyisocyanate compound and an ethyleneimine can be used. Further, as the polyisocyanate compound, the compounds exemplified above can be used. Further, a compound obtained by adding a polyethyleneimine to a polyhydric ester formed of a polyhydric alcohol such as trimethylolpropane or pentaerythritol or (meth)acrylic acid or the like can also be used as a bridging agent (C) according to the present embodiment. .

As the polyaziridine compound, for example, N,N'-hexamethylenebis(1-aziridincarbamide), methylenebis[N-(1-aziridinylcarbonyl)-4- can be used. Aniline], tetramethylolmethane-tris(β-aziridinylpropionate), trimethylolpropane-tris(β-aziridinylpropionate), and the like. Here, among these polyaziridine compounds, for example, a polyaziridine compound which is commercially available under the following trade names: "TAZO" and "TAZM" can be used. [The above is manufactured by Japan Mutual Pharmaceutical Co., Ltd.] "CHEMITITE PZ-33" [made by Nippon Shokubai Co., Ltd.].

As the polyepoxy compound, for example, ethylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tripropylene glycol diglycidyl ether, poly Propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polybutyl ether glycol diglycidyl ether, glycerol diglycidyl ether, glycerol tricondensate Glycerol ether, diglycerol polyglycidyl ether, polyglycerol polyglycidyl ether, resorcinol diglycidyl ether, 2,2-dibromoneopentyl glycol diglycidyl ether, trimethylolpropane tri Glycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, diglycidyl adipate, diglycidyl phthalate, tris (glycidyl) trimeric isocyanate, tri (ring) Tris-(glycidoxyethyl)isocyanurate, 1,3-bis(N,N-glycidylaminomethyl)cyclohexane, N,N,N',N' - tetraglycidyl-m-xylylenediamine or the like.

Among the polyepoxy compounds, a polyepoxy compound containing three or more epoxy groups is preferred. For example, it is preferred to use a polyepoxy compound such as tris(glycidyl)trimeric isocyanate, tris(glycidoxyethyl)trimeric isocyanate, or 1,3-bis(N,N-glycidylamine). Methyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine, and the like. Particularly preferred is the use of: 1,3-bis(N,N-glycidylaminomethyl)cyclohexane, N,N,N',N'-tetraglycidyl-m-xylylenediamine. For example, a polyepoxy compound which is commercially available under the following trade names: "TETRAD-C", "TETRAD-X" [manufactured by Mitsubishi Gas Chemical Co., Ltd.], and the like can be used.

The use amount of the crosslinking agent (C) relative to 100 parts by weight of the acrylic copolymer (A) is 0.01 parts by weight or more, based on 0.5 parts by weight, based on the purpose of imparting sufficient cohesive force to the adhesive composition and suppressing generation of bubbles. The above is better. In addition, the amount of the crosslinking agent (C) to be used in an amount of 5 parts by weight or less based on 100 parts by weight of the acrylic copolymer (A) is 5 parts by weight or less, based on the purpose of suppressing the peeling of the adhesive composition. It is preferably 3 parts by weight or less.

The adhesive composition according to the present embodiment contains 0.01 to 1 part by weight of tris(3-trialkoxydecylalkyl) isocyanurate relative to 100 parts by weight of the acrylic copolymer (A) ( D). The tris(3-trialkoxydecylalkyl) isocyanurate (D) is represented by the following chemical formula [Chemical Formula 1]. Further, R represents an alkyl group having 1 to 3 carbon atoms, and n is an integer of 1 to 3.

As an example of tris(3-trialkoxydecylalkyl)isocyanate (D), tris(3-trimethoxydecylpropyl) isocyanate, trimerization can be used. Tris(3-triethoxydecylpropyl) isocyanate and the like.

The trimeric isocyanic acid in the adhesive composition is based on 100 parts by weight of the acrylic polymer (A) for the purpose of suppressing the occurrence of peeling, foaming, or the like of the adhesive composition in a hot and humid environment. The content of the -trialkoxymercaptoalkyl)ester (D) is preferably 0.01 to 1 part by weight, preferably 0.1 to 0.5 part by weight.

The adhesive composition according to the present embodiment is preferably contained in an amount of 0.001 to 0.2 part by weight based on 100 parts by weight of the acrylic polymer (A), based on the epoxy-based decane coupling agent (E). As the epoxy decane coupling agent (E), the following decane compound having an epoxy structure: 3-glycidoxypropyltrimethoxydecane, 2-(3,4-ethoxycyclohexyl) can be used. Ethyltrimethoxydecane, and the like.

The purpose of suppressing the occurrence of peeling, foaming, and the like of the adhesive composition in a hot and humid environment, and suppressing the change in the adhesive composition due to the temporal change of the adhesive composition, thereby reducing the remanufacturability of the adhesive composition. The content of the epoxy decane coupling agent (E) in the adhesive composition is 0.001 to 0.2 parts by weight, preferably 0.01 to 0.05 parts by weight, based on 100 parts by weight of the acrylic copolymer (A).

The adhesive composition of the present embodiment is composed of the above acrylic polymer (A), polyethene monomer (B), crosslinking agent (C), and tris(3-trialkoxyfluorene). In addition to the alkyl group-based ester (D) and the epoxy-based decane coupling agent (E), various additives can be appropriately formulated in such a range as not to impair the effects exerted by the adhesive composition of the present embodiment. Solvents, weathering stabilizers, tackifiers, plasticizers, softeners, dyes, pigments, inorganic fillers, and the like. The blending amount of the weather stabilizer, the tackifier, the plasticizer, the softener, the dye, the pigment, the inorganic filler, and the like is preferably 30 parts by weight or less based on 100 parts by weight of the acrylic copolymer (A). More preferably, it is 20 parts by weight or less, and most preferably 10 parts by weight or less. By setting the blending amount within this range, an adhesive composition can be obtained which appropriately maintains the balance of adhesion, wettability, heat resistance and reproducibility of the adhesive composition, and obtains various physical properties which are good. .

The optical film of the present embodiment is an optical film having an adhesive layer formed of the adhesive composition of the present embodiment. The specific production method is as follows: an adhesive layer according to the present embodiment is formed on a release sheet, and the side of the adhesive of the laminate of the release sheet/adhesive layer is laminated on the optical film to be peeled off. The laminate of the sheet/adhesive layer/optical film is irradiated with ultraviolet rays from the side of the release sheet, and after the release sheet is peeled off from the laminate, the side of the adhesive layer is pressed against the surface of the support substrate of the liquid crystal cell and bonded. More specifically, a method of forming an adhesive layer on the release sheet is a method in which the adhesive composition of the present embodiment is applied onto a release sheet and dried.

As the release sheet, a synthetic resin sheet such as polyester which is subjected to release treatment by a release agent such as a fluorine resin, a paraffin wax, a wax or a polyfluorene oxide can be used. The thickness of the adhesive layer formed on the release sheet is, for example, 1 to 100 μm after drying, preferably 5 to 50 μm, more preferably 15 to 30 μm.

The adhesive composition applied to the release sheet can also be dried by a hot air dryer at 70 to 120 ° C for 1 to 3 minutes.

As described above, the adhesive composition applied to the release sheet is laminated on the optical film, and the adhesive layer is formed by irradiating ultraviolet rays from the surface of the release sheet. Here, the irradiation condition of the ultraviolet ray is such that the cumulative light amount is from 100 to 1000 mJ/cm ² at a wavelength of 300 to 400 nm. Then, the adhesive composition is photopolymerized by irradiation of ultraviolet rays to obtain an adhesive layer. For ultraviolet radiation, polar lamps such as high-pressure mercury lamps, low-pressure mercury lamps, and metal halide lamps or non-polar lamps can be used.

In the adhesive composition for an optical film of the present embodiment, the polyethylenic monomer (B) dispersed in the acrylic copolymer (A) is photopolymerized by ultraviolet irradiation to form a three-dimensional structure. Further, the crosslinking agent in the acrylic copolymer (A) of the adhesive composition for an optical film forms a crosslinked structure with the crosslinking agent (C). Then, for the purpose of exhibiting sufficient durability of the optical film adhesive composition by sufficient agglutination force and suppressing white defects, the optical film is adhered after the three-dimensional structure and the crosslinked structure are formed. In the agent composition, the gum component is preferably 80% by weight or more, more preferably 90% by weight or more.

Further, the so-called gum component can be measured by the following method.

(Determination of the gel component of the adhesive composition)

The measurement is carried out according to the following (1) to (6).

(1) A solution of the adhesive composition is applied to a release sheet surface-treated with a polyfluorene-based release agent, and the amount of the coating after drying is 25 g/m ² , which is dried by a hot air circulation dryer. The film was dried at 100 ° C for 90 seconds to form a film-shaped pressure-sensitive adhesive layer.

(2) The formed pressure-sensitive adhesive layer was cured for 10 days at 23 ° C and a humidity of 65% RH.

(3) Approximately 0.25 g of the film-like adhesive layer obtained in (2) is attached to a metal mesh (100 mm × 100 mm) having a mesh number of 250 (mesh), and is coated so that the gel component does not leak out. . After that, the weight was accurately measured with a precision balance to prepare a sample.

(4) The above metal mesh was immersed in an ethyl acetate solution for 3 days.

(5) After immersion, the metal mesh was taken out, washed with a small amount of ethyl acetate, and dried at 120 ° C for 24 hours. After that, the weight was accurately measured with a precision balance.

(6) Calculate the gelatinous composition according to the following formula.

Gum component (% by weight) = (C-A) / (B-A) × 100

Wherein A is the weight (g) of the metal mesh, B is the weight of the metal mesh to which the adhesive is attached (weight of the adhesive) (g), and C is the weight of the dried metal mesh after impregnation (weight of the colloidal resin) ( g).

In the optical film of the present embodiment, after the adhesive layer is formed, the adhesion to the alkali-free glass plate is 0.5 to 10 N/25 mm after 24 hours at 50 ° C, and the alkali-free glass plate after 24 hours at 80 ° C. The adhesion and the adhesion to the alkali-free glass plate after 24 hours at 60 ° C and 90% RH were 10 N/25 mm or more.

After the optical film is formed into an adhesive layer, if it is reworked, it can be reworked immediately, or it can be reworked after long-term storage in a relatively good environment. Since the adhesive layer formed by the adhesive of the present embodiment has a higher adhesive force as the temperature is higher and higher, the adhesion to the alkali-free glass plate after 24 hours at 50 ° C is 10N/25mm or less makes it easy to perform redo work.

On the other hand, in the case where the optical film on which the adhesive layer is formed is used for practical use, it is exposed to a high temperature and high humidity, and if the adhesive property is good after leaving the sample at 80 ° C for 24 hours, The adhesive force characteristics of the adhesive layer exposed to high temperatures are considered to be no problem. Further, when the sample was allowed to stand at 60 ° C and 90% RH for 24 hours, the adhesive force characteristics were good, and the adhesive force characteristics of the adhesive layer when exposed to high humidity and high temperature were regarded as no problem. The adhesive layer formed by the adhesive according to the present embodiment has an increased adhesive force when exposed to a high-temperature and high-humidity environment, and the adhesion to the alkali-free glass plate after 24 hours at 80 ° C and at 60 ° C, 90 The adhesion to the alkali-free glass plate after 24 hours at %RH is 10 N/25 mm or more. Since the adhesive layer of the present embodiment has an appropriate cross-linking state represented by the colloidal component, the adhesive strength of the conventional adhesive layer can be suppressed at a high temperature and high humidity by a strong adhesive force and a cohesive force due to crosslinking. Peeling and bubble generation will occur. After the optical film formed with the adhesive layer is adhered to the alkali-free glass plate, the adhesive force after being left at 80 ° C for 24 hours and the adhesive force after being left at 60 ° C and 90% RH for 24 hours, more preferably 20 N / 25 mm the above.

(Effects of the embodiment)

The adhesive composition of the present embodiment, the adhesive layer formed from the adhesive composition, and the optical film including the adhesive layer have the above-described structure, so that the optical film has sufficient adhesion to the adherend, and It is suppressed to a predetermined adhesive force and is excellent in reworkability. Further, in the adhesive composition, the adhesive layer, and the optical film of the present embodiment, when exposed to a high-temperature and high-humidity environment, the adhesive force is increased, and by having a proper cross-linking state represented by a gel component, It does not produce peeling and bubbles which are usually generated under high temperature and high humidity, and can suppress white defects.

[Examples]

(Example 1)

The examples and comparative examples will be described below. In addition, the production of the test piece used in the examples and the comparative examples, and various test methods and evaluation methods are as follows.

(1) Production of optical film for testing

As an example of the optical film, a polarizing film is used to form a polarizing film having an adhesive layer. The adhesive composition was applied onto a release film surface-treated with a polyoxymethylene-based release agent, and the amount of the coating after drying was 25 g/cm ² . Next, it was dried at 100 ° C for 90 seconds in a hot air circulation dryer to form an adhesive layer. Next, the surface on which the adhesive layer is placed is bonded to a polarizing base film (a film obtained by crimping a cellulose triacetate (TAC) film onto both sides of a polarizer using a polyvinyl alcohol (PVA) film as a main body. The inner surface of about 190 μm was crimped by a nip roller. After the pressure bonding, ultraviolet rays of 600 mJ/cm ² were irradiated from the side of the release film surface with a high pressure mercury lamp, and aged at 23 ° C and 65% RH for 10 days to obtain a polarizing film having an adhesive layer.

(2) Determination of adhesion

(2-1) Determination of adhesion after placement in an environment of 50 ° C

After the polarizing film produced in "(1) Preparation of optical film for test" was cut into 25 mm × 150 mm, the polarizing film was pressure-bonded to a non-alkali product manufactured by Corning Co., Ltd. having a thickness of 0.7 mm by a desktop laminator. The glass plate "# 1737" was used as a test sample. This sample was subjected to hot pressing treatment (50 ° C, 5 kg/cm ² , 20 minutes). Then, the sample was allowed to stand under the conditions of 23 ° C and 65% RH for 1 hour, and then treated at 50 ° C for 24 hours. Subsequently, the mixture was allowed to stand under conditions of 23° C. and 65% RH for 1 hour (conditioning treatment), and then the adhesion at the 180-degree peeling (peeling speed: 300 mm/min) was measured. Further, in the embodiments and examples of the present invention, the "adhesion force of the alkali-free glass plate after passing the adhesive layer for 24 hours at 50 ° C" means the adhesive force measured by the test method. .

(2-2) Determination of adhesion after placement in an environment of 80 ° C

The test sample prepared in the same manner as in "(2-1) Measurement of adhesive force after being placed in an environment of 50 ° C] was placed under conditions of 23 ° C and 65% RH for 1 hour, and then The treatment was carried out at 80 ° C for 24 hours. Subsequently, it was allowed to stand under conditions of 23 ° C and 65% RH for 1 hour (adjustment treatment). The adhesion at a peeling degree of 180 degrees (peeling speed: 300 mm/min) was measured. Further, in the embodiments and examples of the present invention, the "adhesion force of the alkali-free glass plate after 24 hours at 80 ° C" means the adhesive force measured by the test method.

(2-3) Determination of adhesion after placement in an environment of 60 ° C × 90% RH

The test sample prepared in the same manner as in "(2-1) Measurement of adhesive force after being placed in an environment of 50 ° C] was placed under conditions of 23 ° C and 65% RH for 1 hour, and then Treatment at 60 ° C, 90% RH for 24 hours. Subsequently, the mixture was allowed to stand under conditions of 23° C. and 65% RH for 1 hour (adjustment treatment), and then the adhesion at the 180-degree peeling (peeling speed: 300 mm/min) was measured. Further, in the embodiment and the examples of the present invention, the "adhesion force of the alkali-free glass plate after 24 hours at 60 ° C and 90% RH" means the adhesive force measured by the test method.

(3) Evaluation of redo

The adhesion to the alkali-free glass plate after 24 hours at 50 ° C was measured and measured in "Measurement of Adhesion Force After Placement in (2-1) at 50 ° C".

◎: 10N/25mm or less.

○: more than 10 N/25 mm and 15 N/25 mm or less.

X: Greater than 15N/25mm.

(4) Evaluation of durability

A 70 mm × 140 mm (long side) test piece was attached to a single side of a 0.7 mm non-alkali glass plate "#1737" manufactured by Corning Co., Ltd. using a laminator. The test piece was "(1) Optical film for test. The polarizing film having the adhesive layer produced in the "manufacture" is cut at an angle of 45° with respect to the absorption axis. Next, this sample was subjected to hot pressing treatment (50 ° C, 5 kg/cm ² , 20 minutes), and allowed to stand under conditions of 23 ° C and 65% RH for 24 hours (conditioning treatment). Thereafter, it was allowed to stand for 1000 hours under the subsequent temperature and humidity conditions, and the evaluation was carried out by visually observing the state of foaming, peeling, and floating. The evaluation criteria are as follows.

a) 80 ° C, dry (80 ° C, drying evaluation criteria)

◎: No disadvantage of foaming, peeling, floating, or a defect from the edge of the outer edge was 0.3 mm or more.

○: The disadvantage that the size of the foaming, peeling, floating, or the outer edge portion was 0.9 mm or more was not observed.

X: The disadvantage of having a size of 0.9 mm or more in foaming, peeling, floating, or a defect from the edge of the outer edge was found.

b) 60 ° C, 90% RH (60 ° C, 90% RH evaluation basis)

◎: No disadvantage of foaming, peeling, floating, or a defect from the edge of the outer edge was 0.3 mm or more.

○: The disadvantage that the size of the foaming, peeling, floating, or the outer edge portion was 0.9 mm or more was not observed.

X: The disadvantage of having a size of 0.9 mm or more in foaming, peeling, floating, or a defect from the edge of the outer edge was found.

(5) Evaluation test of white defect phenomenon

A test sample was prepared by attaching a polarizing film having an adhesive layer having the same size as "(4) Evaluation of durability" to both sides of an alkali-free glass plate "#1737" manufactured by Corning Co., Ltd. of 0.7 mm. And the polarizing film having the adhesive layer and its polarizing axis intersect each other perpendicularly. Then, the conditioning treatment was carried out in the same manner as in "(2) Measurement of adhesive strength", and then left at 80 ° C for 500 hours under dry conditions. After standing, a uniform light source was used under conditions of 23 ° C and 65% RH, and the white defect state was observed by visual observation. The evaluation criteria are as follows.

◎: White defects were not detected at all.

○: White defects were hardly noticed.

X: The area of white defects is large.

(Manufacture of Acrylic Copolymer (A))

(Manufacturing Example 1)

In a reactor equipped with a thermometer, a stirrer, a nitrogen introduction tube, and a reflux cooling tube, 96.2 parts by weight of n-butyl acrylate (BA), 0.6 parts by weight of acrylic acid (AA), and 3.2 parts by weight of 2-hydroxy acrylate were placed. Ethyl ester (2HEA), 100 parts by weight of ethyl acetate (EAc), and 0.2 parts by weight of azobisisobutyronitrile (AIBN) were substituted with nitrogen for the reaction vessel. Thereafter, the temperature of the contents of the reaction vessel was raised to 65 ° C under stirring in a nitrogen atmosphere for 6 hours, and further the temperature was raised to 70 ° C and reacted for 2 hours. Thereafter, a solution obtained by dissolving 0.4 part by weight of AIBN in 20 parts by weight of EAC was added dropwise thereto over 1 hour, and further reacted for 2 hours. After completion of the reaction, the reaction mixture was diluted with toluene to obtain an acrylic copolymer solution having a solid content of 17.7% by weight and a viscosity of 5030 mPa·s. The weight average molecular weight of the acrylic polymer was 1.31 million.

(Manufacturing Example 2)

Polymerization was carried out in the same manner as in Production Example 1, except that the copolymer composition was set to the monomer composition shown in each of the production examples of Table 1, except that the copolymer composition used in Production Example 1 was used. The copolymer composition, solid content, glass transition temperature (Tg), and weight average molecular weight (Mw) of Production Example 2 are shown in Table 1.

(Manufacturing Example 3)

Polymerization was carried out in the same manner as in Production Example 1, except that the copolymer composition was set to the monomer composition shown in each of the production examples of Table 1, except that the copolymer composition used in Production Example 1 was used. The copolymer composition, solid content, glass transition temperature (Tg), and weight average molecular weight (Mw) of Production Example 3 are shown in Table 1.

In addition, in Table 1, "OH/COOH" means that (% by weight of the hydroxyl group-containing monomer contained in the acrylic copolymer (A)) is divided by (acrylic copolymer (A)) The value of % by weight of the carboxyl group-containing monomer. Specifically, "OH/COOH" in Production Example 1 was 5.3. Moreover, "OH/COOH" in Production Example 2 was 1.7. Further, "OH/COOH" in Production Example 3 was 0.5.

(Manufacture of composition of pressure-sensitive adhesive for polarizing plate)

(Example 1)

565 parts by weight of the acrylic copolymer solution (100 parts by weight of the acrylic copolymer) synthesized in Production Example 1 was used as the acrylic copolymer (A), and 10 parts by weight of trimethylolpropane triacrylate was used as the The vinyl monomer (B) and 4 parts by weight of Coronate L (polyisocyanate compound manufactured by Nippon Polyurethane Industry Co., Ltd., and an active ingredient of 3 parts by weight) are used as the crosslinking agent (C) in an amount of 0.2 part by weight. Tris(3-trimethoxymercaptopropyl) polyisocyanate (a decane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd., trade name X-12-965, active ingredient 0.2 parts by weight) as a trimeric Tris(3-trialkoxydecylalkyl)cyanate, 0.01 parts by weight of 3-glycidoxypropyltrimethoxydecane (a sterane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd., trade name It is 0.01 part by weight of KBM-403, as an epoxy decane coupling agent (E), and 0.3 part by weight of IRGACURE 500 (a photopolymerization initiator made by Ciba Specialty Chemicals Co., Ltd., which has a composition of 1) a 1:1 (by weight) mixture of hydroxycyclohexyl phenyl ketone and diphenyl ketone as photopolymerization As the starting agent, the above components are thoroughly stirred and mixed to obtain an adhesive composition. Using the obtained adhesive composition, a test optical film was produced by the above-described method for producing an optical film for testing, and various measurements described above were carried out. The results are shown in Table 3-1.

(Examples 2 to 10, Comparative Examples 1 to 4)

An adhesive composition was prepared in the same manner as in Example 1 except that the blending compositions of the respective examples and comparative examples shown in Tables 2-1 and 2-2 were used instead of the blending composition in Example 1. The adhesive compositions of Examples 2 to 10, and the adhesive compositions of Comparative Examples 1 to 4). Using the obtained adhesive composition, a test optical film was produced by the above-described method for producing an optical film for testing, and various measurements described above were carried out. The results are shown in Table 3-1 and Table 3-2.

In addition, the formulation of each of Table 2-1 and Table 2-2 is abbreviated as follows, and the addition amount of each component is the weight part of an active component.

(a) TMPTA "trimethylolpropane triacrylate"

Polyvinyl monomer (B) component

(b) Coronate L "Polyisocyanate compound manufactured by Nippon Polyurethane Industry Co., Ltd."

The active ingredient is 75%, and the crosslinking agent (C) component

(c) TMSI; "The decane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd."

Product name; X-12-965, active ingredient is 100%

Chemical name; tris(3-trimethoxydecylpropyl) isocyanate, tris(3-trialkoxydecylalkyl) isocyanate (D)

(d) KBM-403; "The decane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd."

Product name; KBM-403, active ingredient 100%

Chemical name; 3-glycidoxypropyltrimethoxydecane, epoxy decane coupling agent (E) component

(e) KBE-9007; "The decane coupling agent manufactured by Shin-Etsu Chemical Co., Ltd."

Product name; KBE-9007, active ingredient 100%

Chemical name; 3-isocyanate propyl triethoxy decane

(f) IRGACURE 500; "Photopolymerization starter made by Ciba Specialty Chemicals Co., Ltd."

Composition: 1:1 (by weight) eutectic mixture of 1-hydroxycyclohexyl phenyl ketone and diphenyl ketone, the active ingredient is 100%

Referring to Table 3-1, in all of the optical films of Examples 1 to 10, in all items of reworkability, durability (80 ° C), durability (60 ° C × 90% RH), and white defects, "◎" or "○" is displayed based on the evaluation criteria. That is, the optical films of all of Examples 1 to 10 exhibit excellent durability even in a high-temperature and high-humidity environment, and at the same time, white defects can be suppressed, and can be easily performed in the case where re-attachment is required. Do it again.

Further, the optical film having the adhesive for an optical film of the present embodiment and the embodiment is excellent in reworkability, does not cause peeling or bubbles which are usually generated under high temperature and high humidity, and can suppress white defects. Optical film for display devices such as personal computers, televisions, and satellite navigation systems.

The embodiments and examples of the invention are described above, but the invention in the claims is not limited to the embodiments and examples described above. Further, it should be noted that the means necessary for solving the problems of the invention are not necessarily all of the combinations of features described in the embodiments and the examples.

Claims (5)

An adhesive composition comprising: an acrylic copolymer (A); and 1 to 30 parts by weight of a polyethylenic monomer (B), 0.01 to 5 with respect to 100 parts by weight of the acrylic copolymer (A) Parts by weight of the crosslinking agent (C), 0.01 to 1 part by weight of tris(3-trialkoxydecylalkyl) isocyanurate (D), and 0.001 to 0.2 parts by weight of epoxy decane Coupling agent (E). The adhesive composition according to claim 1, wherein the acrylic copolymer (A) contains 0.1 to 10% by weight of a hydroxyl group-containing monomer and 0.1 to 3% by weight of a carboxyl group-containing monomer as a copolymerization. The value of the component (by weight% of the hydroxyl group-containing monomer contained in the acrylic copolymer (A)) divided by (% by weight of the carboxyl group-containing monomer contained in the acrylic copolymer (A)) is 0.1 to 30. An optical film having an adhesive layer formed of an adhesive composition containing: an acrylic copolymer (A); and 1 with respect to 100 parts by weight of the acrylic copolymer (A) ~30 parts by weight of the polyvinyl monomer (B), 0.01 to 5 parts by weight of the crosslinking agent (C), and 0.01 to 1 part by weight of tris(3-trialkoxydecane) The ester (D) and the 0.001 to 0.2 part by weight of the epoxy decane coupling agent (E). The optical film according to claim 3, wherein the acrylic copolymer (A) contains 0.1 to 10% by weight of a hydroxyl group-containing monomer and 0.1 to 3% by weight of a carboxyl group-containing monomer as a copolymerization component. Further, the value of (% by weight of the hydroxyl group-containing monomer contained in the acrylic copolymer (A)) divided by (% by weight of the carboxyl group-containing monomer contained in the acrylic copolymer (A)) is 0.1 to 30. The optical film according to claim 4, wherein after the adhesive layer is formed, the adhesion to the alkali-free glass plate is 0.5 to 10 N/25 mm after 24 hours at 50 ° C, and 24 hours at 80 ° C. The adhesion to the alkali-free glass plate and the adhesion to the alkali-free glass plate after 24 hours at 60 ° C and 90% RH (relative humidity) were 10 N/25 mm or more.