TWI457412B - Adhesive composition, optical member, surface protective film and adhesive sheet - Google Patents

Description

Adhesive composition, optical component, surface protective film and adhesive sheet (1) Field of invention

This invention relates to adhesive compositions. More specifically, the present invention relates to a binder composition having a long pot life to obtain excellent workability after a bonding treatment and to exhibit usable adhesive properties in a short aging time.

Background of the invention

Recently, flat panel displays (FPDs) such as liquid crystal displays (LCDs), plasma display panels (PDPs), and organic electroluminescence (EL) displays have been increasingly used. Therefore, there is a need to improve the processability and productivity of adhesives for FPD.

JP 2007-211091 discloses a binder composition comprising an acrylic polymer, an isocyanate curing agent or an epoxy curing agent and an imidazolium compound, and exhibits excellent durability under high temperature and high humidity conditions. However, the adhesive layer formed from such a binder composition requires a long aging time of 1 day or longer to exhibit usable adhesive properties after crosslinking, thereby reducing productivity.

JP H11-293222 discloses a binder composition comprising an acrylic polymer and an isocyanate group-containing carbodiimide compound as a curing agent. Because of its high cross-linking rate and strong adhesion and adhesion, the adhesive composition is suitable for bonding inorganic materials such as glass, ceramics and tiles. Further, the adhesive composition exhibits excellent adhesion, water resistance and moisture resistance due to rapid increase in adhesion under normal conditions, and also exhibits heat resistance so that it does not swell at a high temperature. Moreover, the adhesive does not remain as a binder when separated from the adherend. However, the adhesive layer formed from the adhesive composition also requires a long aging time of one day or longer to exhibit usable adhesive properties after crosslinking, thereby reducing productivity.

JP S58-13623 discloses the use of an imidazole compound as a curing agent or curing accelerator for an epoxy resin. However, it does not indicate that the imidazole compound is used as a curing agent or a curing accelerator for an acrylic adhesive.

Summary of invention

One aspect of the present invention provides a binder composition which has a long shelf life after bonding treatment to obtain excellent processability and exhibits useful binder properties in a short aging time of 0.5 days. To provide excellent productivity.

The adhesive composition can effectively bond a plurality of adherends, and the adhesive layer formed of the adhesive composition can be suitably used as an adhesive layer, a surface protective film, and an adhesive sheet of an optical element.

The binder composition comprises: (A) 100 parts by weight of a (meth)acrylic copolymer having a weight average molecular weight of from about 100,000 to about 2,000,000 g/mol, and (B) from about 0.05 to about 5 parts by weight of carbon dioxime. An imine crosslinking agent, and (C) from about 0.001 to about 5 parts by weight of the imidazole compound represented by Formula 1:

Wherein R ¹ , R ² and R ³ each independently represent a hydrogen atom, a halogen atom or a substituted or unsubstituted C1 to C10 linear or branched alkyl group.

The (meth)acrylic copolymer (A) comprises: (a1) from about 0 to about 9 parts by weight of a carboxyl group-containing monomer, and (a2) from about 0 to about 9 parts by weight of a hydroxyl group-containing (meth)acrylic acid. Monomer, and (a3) from about 82 to about 99.9 parts by weight of a (meth) acrylate monomer. (At this time, it should be noted that the total amount of the carboxyl group-containing monomer (a1) and the hydroxyl group-containing (meth)acrylic monomer (a2) is not 0 parts by weight, and the carboxyl group-containing monomer (a1), hydroxyl group-containing The total amount of the (meth)acrylic monomer (a2) and the (meth)acrylate monomer (a3) is about 100 parts by weight.

detailed description

According to the present invention, the binder composition comprises: (A) 100 parts by weight of a (meth)acrylic copolymer having a weight average molecular weight of from about 100,000 to about 2,000,000 g/mol, and (B) from about 0.05 to about 5 parts by weight of carbon. The diimine imide crosslinker, and (C) from about 0.001 to about 5 parts by weight of the imidazole compound represented by Formula 1.

The (meth)acrylic copolymer (A) comprises from about 0 to about 9 parts by weight of the carboxyl group-containing monomer from (a1), and (a2) from about 0 to about 9 parts by weight of the hydroxyl group-containing (meth)acrylic monomer. And (a3) from about 82 to about 99.9 parts by weight of a monomer composed of a (meth) acrylate monomer. (At this time, it should be noted that the total amount of the carboxyl group-containing monomer (a1) and the hydroxyl group-containing (meth)acrylic monomer (a2) is not 0 parts by weight, and the carboxyl group-containing monomer (a1), hydroxyl group-containing The total amount of the (meth)acrylic monomer (a2) and the (meth)acrylate monomer (a3) is about 100 parts by weight.

The above binder composition includes a carbodiimide crosslinking agent and an imidazole compound as a crosslinking agent. When a carbodiimide cross-linking agent and an imidazole compound are used together, the adhesive composition has a long shelf life and enables the adhesive layer to crosslink (curing) in a short aging time after the bonding treatment without affecting the adhesive property. , thereby substantially improving workability and productivity.

Further, the adhesive layer formed of the adhesive composition according to the present invention can be used as a binder for an optical element, which has not only a suitable bonding strength and adhesion to a substrate, but also excellent metal corrosion control. And prevent performance, light leakage resistance, durability, resistance to adherence, low temperature stability and reworkability.

Further, the adhesive layer formed of the adhesive composition according to the present invention can be used as a binder for a surface protective film having a suitable adhesive strength or adhesion to a substrate, exhibiting excellent metal corrosion control and prevention. Performance, resistance to adherent contamination, low temperature stability and transparency, and control/preventing air bubbles under high temperature and high pressure conditions (when autoclaving).

Furthermore, the adhesive layer formed from the adhesive composition according to the present invention can be used as a binder for a binder sheet which has a suitable bonding strength or adhesion to a substrate and exhibits excellent metal corrosion control and Prevents performance, resistance to adherence, low temperature stability and transparency, heat resistance and moisture/heat resistance.

The components of the composition according to the invention will be explained in more detail below. The term "(meth)acrylate" as used herein generally refers to both acrylate and methacrylate. Further, the (meth) compound as a whole means both a compound and a (meth)-containing compound. For example, "(meth)acrylinyl" includes both acryloyl and methacrylamidyl groups, "(meth)acrylate" includes both acrylate and methacrylate, and "(meth)acrylic acid "includes both acrylic acid and methacrylic acid.

(A) (meth)acrylic acid copolymer

The (meth)acrylic copolymer (hereinafter also referred to as "component (A)") used in the present invention contains from about 0 to about 9 parts by weight of the carboxyl group-containing monomer from (a1), (a2) from about 0 to About 9 parts by weight of the hydroxyl group-containing (meth)acrylic monomer, and (a3) about 82 to about 99.9 parts by weight of a monomer composed of a (meth) acrylate monomer. At this time, it should be noted that the total amount of the carboxyl group-containing monomer (a1) and the hydroxyl group-containing (meth)acrylic monomer (a2) is not 0 parts by weight, and the carboxyl group-containing monomer (a1) and the hydroxyl group-containing ( The total amount of the (meth)acrylic monomer (a2) and the (meth)acrylate monomer (a3) is about 100 parts by weight. The (meth)acrylic copolymer has a weight average molecular weight of from about 100,000 to about 2,000,000 g/mol.

(a1) a monomer having a carboxyl group

The carboxyl group-containing monomer (hereinafter also referred to as "component (a1)")) is an unsaturated monomer having at least one carboxyl group. Examples of the carboxyl group-containing monomer may include, but are not limited to, (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, itaconic anhydride, tetradecanoic acid, Palmitic acid, oleic acid, etc. These monomers may be used singly or in combination of two or more kinds thereof.

Specifically, (meth)acrylic acid, maleic acid, maleic anhydride, fumaric acid, fumaric anhydride, crotonic acid, itaconic acid, itaconic anhydride is preferred, and (meth)acrylic acid is more preferred.

The carboxyl group-containing monomer can be used in an amount of from about 0 to about 9 parts by weight. Within this range, a suitable crosslinking point can be formed by the reaction of a carboxyl group with a carbodiimide crosslinking agent (B), thereby ensuring the flexibility of the binder composition and the light leakage resistance and durability of the binder layer.

(a2) hydroxyl group-containing (meth)acrylic monomer

The hydroxyl group-containing (meth)acrylic monomer (hereinafter also referred to as "component (a2)") means a (meth)acrylic monomer having a hydroxyl group in the molecule. Examples of the hydroxyl group-containing (meth)acrylic monomer may include, but are not limited to, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and 1,6-hexanediol. (Meth) acrylate, pentaerythritol tri(meth) acrylate, dipentaerythritol penta (meth) acrylate, neopentyl glycol mono (meth) acrylate, trimethylolpropane di (meth) acrylate , trimethylolethane di(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl (meth)acrylate, 2-hydroxy-3-phenoxypropyl (Meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, N-2-hydroxyethyl (meth) acrylamide, cyclohexane dimethanol monomethacrylate, and the like. Further, the hydroxyl group-containing (meth)acrylic monomer may include a glycidyl group-containing compound such as alkyl glycidyl ether, allyl glycidyl ether, and glycidyl (meth)acrylate with (meth)acrylic acid plus The resulting compound is reacted. These monomers may be used singly or in combination of them.

Specifically, 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, N-2-hydroxyethyl (meth) acrylamide, and cyclohexane dimethanol monomethyl are preferred. The acrylate is more preferably 2-hydroxyethyl (meth)acrylate, 4-hydroxybutyl (meth)acrylate, and N-2-hydroxyethyl (meth) acrylamide.

The hydroxyl group-containing (meth)acrylic monomer may be used in an amount of from about 0 to about 9 parts by weight. Within this range, a suitable crosslinking point is formed via the reaction of a hydroxyl group with a carbodiimide crosslinking agent (B), thereby ensuring the flexibility of the binder composition and the light leakage resistance and durability of the binder layer.

(a3) (meth) acrylate monomer

The (meth) acrylate monomer (hereinafter also referred to as "component (a3)") is an ester of (meth)acrylic acid having no hydroxyl group in the molecule. Examples of the (meth) acrylate monomer may include, but are not limited to, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, ( N-butyl acrylate, isobutyl (meth)acrylate, tert-butyl (meth)acrylate, isoamyl (meth)acrylate, n-hexyl (meth)acrylate, n-heptyl (meth)acrylate Ester, n-octyl (meth)acrylate, t-octyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, decyl (meth)acrylate, isodecyl (meth)acrylate, Tridecyl (meth)acrylate, octadecyl (meth)acrylate, isostearyl (meth)acrylate, phenyl (meth)acrylate, benzyl (meth)acrylate, (meth)acrylic acid Diester, tetrahydrofuranyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, 2-ethyl hexane diol (meth) acrylate, butyl Oxyethyl (meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2-(2-methoxyethoxy) B Base (meth) acrylate, 2-(2-butoxy ethoxy) Ethyl (meth) acrylate, 4-butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-trimethylphenyl (meth) acrylate, phenoxy Methyl (meth) acrylate, phenoxyethyl (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polypropylene oxide monoalkyl ether (methyl) Acrylate, trifluoroethyl (meth) acrylate, pentafluorooxyethyl (meth) acrylate, 2-chloroethyl (meth) acrylate, 2, 3- dibromopropyl (A) Acrylate, tribromophenyl (meth) acrylate, and the like. These (meth) acrylate monomers may be used singly or in combination of two or more kinds thereof.

Specifically, methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate are preferred, and (meth)acrylic acid is more preferred. Ester, n-butyl (meth)acrylate and 2-ethylhexyl (meth)acrylate.

The (meth) acrylate monomer (a3) may be used in an amount of from about 82 to about 99.9 parts by weight.

The (meth)acrylic copolymer (A) can be produced by any known method using a polymerization initiator without particular limitation, such as solution polymerization, emulsion polymerization, suspension polymerization, reverse phase suspension polymerization, film polymerization, and spray polymerization. The polymerization control can be carried out via adiabatic polymerization, temperature-controlled polymerization, and isothermal polymerization. In addition to the method of initiating polymerization using a polymerization initiator, radiation, electromagnetic radiation, and UV radiation can be used to initiate polymerization. Specifically, solution polymerization using a polymerization initiator can be used, so that the molecular weight can be easily adjusted, and impurities can be reduced. For example, by using ethyl acetate, toluene or methyl ethyl ketone as a solvent, about 0.01 to 0.5 part by weight of a polymerization initiator is added to about 100 parts by weight of the total amount of the monomer, followed by a nitrogen atmosphere at about 60 to 90 ° C. The (meth)acrylic copolymer can be prepared by reacting for about 3 to 10 hours. Examples of the polymerization initiator may include: azo compounds such as azobisisobutyronitrile (AIBN), 2-2 ' -azo (2-methylbutyronitrile), and azobiscyanovaleric acid; organic peroxidation Such as t-butyl peroxypivalate, t-butyl peroxybenzoate, t-butyl peroxy-2-ethylhexanoate, di-tert-butyl peroxide, isopropylbenzene hydrogen Peroxide, benzammonium peroxide and t-butyl hydroperoxide, and inorganic peroxides such as hydrogen peroxide, ammonium persulfate, potassium persulfate, sodium persulfate, and the like. These initiators may be used singly or in combination of two or more kinds thereof.

The above copolymer may further include other monomers copolymerizable with the monomers (a1) to (a3), as needed. Examples of other monomers may include, but are not limited to, epoxy group-containing acrylic monomers such as glycidyl (meth)acrylate and methyl glycidyl (meth)acrylate; amino group-containing acrylic monomers, Such as dimethylaminoethyl (meth) acrylate, diethyl amino ethyl (meth) acrylate, N-tert-butyl amino ethyl (meth) acrylate and methacryloxy Ethyltrimethylammonium chloride (meth) acrylate; acrylamide-containing acrylic monomer such as (meth) acrylamide, N-hydroxymethyl (meth) acrylamide, N-A Oxymethyl (meth) acrylamide and N, N-methylene bis (meth) acrylamide; phosphate monomers containing acrylate groups, such as 2-methacryloxyethyl diphenyl Phosphate (meth) acrylate, trimethyl propylene oxyethyl phosphate (meth) acrylate and tripropylene methoxyethyl phosphate (meth) acrylate; sulfonic acid group-containing acrylic acid Monomers such as sodium sulfopropyl propyl (meth) acrylate, sodium 2-sulfonyl ethyl (meth) acrylate and sodium 2- acrylamido-2-methyl propane sulfonate Amino acid group-containing acrylic acid , such as urethane (meth) acrylate; phenyl-containing acryl vinyl monomers, such as p-tert-butyl phenyl (meth) acrylate and o-diphenyl (meth) acrylate; A vinyl group of a decyl group such as 2-acetamethyleneoxyethyl (meth) acrylate, vinyl trimethoxy decane, vinyl triethoxy decane, vinyl tris (β-methoxy) Ethyl)decane, vinyltriethoxydecane and methacryloxypropyltrimethoxydecane; and styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate Ester, vinyl propionate, acrylonitrile, vinyl pyridine, and the like. These monomers may be used singly or in combination of two or more kinds thereof.

Specifically, (meth) acrylamide, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2-ethyl acetoxyethyl (meth) Acrylate and vinyl acetate; more preferably (meth) acrylamide and vinyl acetate.

The other monomer may be used in an amount of about 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, more preferably 0.3 to 3 parts by weight, based on the total amount of about 100 parts by weight of the monomers (a1) to (a3).

The (meth)acrylic copolymer (A) obtained from the above monomer may have a weight average molecular weight Mw of from about 100,000 to about 2,000,000 g/mol. If the weight average molecular weight thereof is less than about 100,000 g/mol, the obtained heat resistance is insufficient. If the weight average molecular weight exceeds about 2,000,000 g/mol, low adhesion and viscosity reduction are obtained. In the present invention, the weight average molecular weight is based on the polystyrene standard determined by the method described in the following examples.

At this time, it should be noted that the total amount of the monomer (a1) and the monomer (a2) is not 0 parts by weight. That is, the (meth)acrylic copolymer (A) must include at least one of a constituent unit derived from the monomer (a1) and a constituent unit derived from the monomer (a2). Further, the total amount of the monomers (a1), (a2) and (a3) is about 100 parts by weight.

The above (meth)acrylic copolymer (A) may be used singly or in combination of at least two polymers.

(B) carbodiimide curing agent

In addition to the copolymer (A), the binder composition further includes a carbodiimide crosslinking agent (hereinafter also referred to as "component (B)"). The carbodiimide crosslinking agent reacts with and is attached to the hydroxyl group and/or the carboxyl group of the (meth)acrylic copolymer (A) to form a crosslinked structure.

The carbodiimide crosslinking agent may include any carbodiimide crosslinking agent known in the art, and is not particularly limited. For example, a compound having at least two carbodiimide groups (-N=C=N-) can be used, and any polycarbodiimide known in the art can be used.

Further, the carbodiimide compound may include a high molecular weight polycarbodiimide prepared by a decarburization condensation reaction of a diisocyanate in the presence of a carbodiimide catalyst.

Examples of the above compounds may include a compound obtained by a decarburization condensation reaction of the following diisocyanate.

Examples of the above diisocyanate may include 4,4'-diphenylmethane diisocyanate, 3,3'-dimethoxy-4,4'-diphenylmethane diisocyanate, 3,3'-dimethyl- 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyl ether diisocyanate, 3,3'-dimethyl-4,4'-diphenyl ether diisocyanate, 2,4-toluene Diisocyanate, 2,6-toluene diisocyanate, 1-methoxyphenyl-2,4-diisocyanate, isophorone diisocyanate, 4,4'-dicyclohexylmethane diisocyanate and tetramethylxylene A diisocyanate or the like, which may be used singly or in combination of two or more thereof.

Examples of the carbodiimide catalyst may include a cyclophosphene oxide such as 1-phenyl-2-cyclophosphene-1-oxide, 3-methyl-2-cyclophosphene-1- Oxide, 1-ethyl-3-methyl-2-cyclophosphene-1-oxide, 1-ethyl-2-cyclophosphene-1-oxide and their 3-cyclophosphene isomers .

These high molecular weight polycarbodiimides can be obtained synthetically or from commercially available products. Commercially available products of component (B) may include excellent compatibility with organic solvents (Nisshinbo Chemical Inc.), especially V-01, V-03, V-05, V-07 and V09.

The carbodiimide crosslinking agent (B) may be included in an amount of from about 0.05 to about 5 parts by weight based on 100 parts by weight of the (meth)acrylic copolymer (A). Within this range, a suitable crosslinked structure is formed to achieve excellent heat resistance. If the amount of the carbodiimide crosslinking agent (B) is less than about 0.05 parts by weight, a sufficiently crosslinked structure is not formed, thereby lowering heat resistance. If the amount of the carbodiimide crosslinking agent (B) exceeds about 5 parts by weight, the crosslinking reaction proceeds excessively until the viscosity is lowered, so that the polarizing plate does not shrink with time, thereby reducing light leakage resistance and durability.

The above carbodiimide crosslinking agent (B) may be used singly or in combination of at least two.

(C) imidazole compound

The binder composition includes an imidazole compound (hereinafter also referred to as "component (C)") in addition to the component (A) and the component (B). The imidazole compound is considered to function as a crosslinking (curing) accelerator which acts as a carbodiimide crosslinking agent. A composition comprising both a carbodiimide crosslinker and an adhesive of an imidazole compound achieves a useful adhesive property in a short aging time, thereby having excellent productivity.

The imidazole compound used in the present invention is represented by Formula 1:

Wherein R ¹ , R ² and R ³ each independently represent a hydrogen atom, a halogen atom or a substituted or unsubstituted C1 to C10 linear or branched alkyl group.

Examples of the halogen atom may include a fluorine atom, a chlorine atom, a bromine atom or an iodine atom.

Examples of the linear or branched alkyl group of C1 to C10 may include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, n-pentyl, and iso- Pentyl, tert-amyl, neopentyl, n-hexyl, 3-methylpentan-2-yl, 3-methylpentan-3-yl, 4-methylpentyl, 4-methylpentane- 2-yl, 1,3-dimethylbutyl, 3,3-dimethylbutyl, 3,3-dimethylbutan-2-yl, n-heptyl, 1-methylhexyl, 3- Methylhexyl, 4-methylhexyl, 5-methylhexyl, 1-ethylpentyl, 1-(n-propyl)butyl, 1,1-dimethylpentyl, 1,4-dimethyl Pentyl, 1,1-diethylpropyl, 1,3,3-trimethylbutyl, 1-ethyl-2,2-dimethylpropyl, n-octyl, 2-ethylhexyl, 2-methylhexane-2-yl, 2,4-dimethylpentan-3-yl, 1,1-dimethylpentan-1-yl, 2,2-dimethylhexane-3 -yl, 2,3-dimethylhexane-2-yl, 2,4-dimethylhexane-2-yl, 2,5-dimethylhexane-2-yl, 3,4-di Methyl hexane-3-yl, 3,5-dimethylhexane-3-yl, 1-methylheptyl, 2-methylheptyl, 5-methylheptyl, 2-methylheptane -2-yl, 3-methylheptan-3-yl, 4-methylheptan-3-yl, 4-methyl Heptan-4-yl, 1-ethylhexyl, 2-ethylhexyl, 1-propylpentyl, 2-propylpentyl, 1,1-dimethylhexyl, 1,4-dimethylhexyl 1,5-Dimethylhexyl, 1-ethyl-1-methylpentyl, 1-ethyl-4-methylpentyl, 1,1,4-trimethylpentyl, 2,4, 4-trimethylpentyl, 1-isopropyl-1,2-dimethylpropyl, 1,1,3,3-tetramethylbutyl, n-decyl, 1-methyloctyl, 6 -methyloctyl, 1-ethylheptyl, 1-(n-butyl)pentyl, 4-methyl-1-(n-propyl)pentyl, 1,5,5-trimethylhexyl, 1 1,5-trimethylhexyl, 2-methyloctane-3-yl, n-decyl, 1-methylindenyl, 1-ethyloctyl, 1-(n-butyl)hexyl, 1, 1-dimethyloctyl, 3,7-dimethyloctyl and the like.

The above alkyl group may be substituted with a substituent. Examples of the substituent may include a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom; an alkyl group such as a methyl group, an ethyl group, a t-butyl group, and a dodecyl group; and an aryl group such as a phenyl group or a p-tolyl group. , xylyl, cumenyl, naphthyl, anthryl and phenanthryl; alkoxy such as methoxy, ethoxy and tert-butoxy; aryloxy, such as phenoxy and p-tolyloxy; Alkoxycarbonyl, such as methoxycarbonyl, butoxycarbonyl and octyloxycarbonyl; phenoxycarbonyl; anthracenyloxy, such as ethoxylated, propyloxy, methacryloxy and benzoyl Alkoxy; sulfhydryl, such as acetamido, benzhydryl, isobutyl fluorenyl, acryl fluorenyl, methacryl fluorenyl, methoxalyl group; alkylamine group, such as methylamine and ring Hexylamino; dialkylamino, such as dimethylamino, diethylamino, morpholinyl and piperidinyl; arylamine groups, such as anilino and p-toluidine; hydroxyl, carboxyl, formate, amine , nitro, cyano, trifluoromethyl, trichloromethyl, and the like.

Examples of the imidazole compound may include imidazole, 1-methylimidazole, 2-methylimidazole, 4-methylimidazole, 1-ethylimidazole, 2-ethylimidazole, 4-ethylimidazole, 1-propylimidazole, 2-propylimidazole, 4-propylimidazole, 1-butylimidazole, 2-butylimidazole, 4-butylimidazole, 1-pentylimidazole, 2-pentylimidazole, 4-pentylimidazole, 1- Hexyl imidazole, 2-hexyl imidazole, 4-hexyl imidazole, 1-heptyl imidazole, 2-heptyl imidazole, 4-heptyl imidazole, 1-octyl imidazole, 2-octyl imidazole, 4-octyl imidazole, 1 - mercapto imidazole, 2-mercaptoimidazole, 4-mercaptoimidazole, 1-mercaptoimidazole, 2-mercaptoimidazole, 4-mercaptoimidazole, 1,2-dimethylimidazole, 1,2-diethyl Imidazole, 1-ethyl-2-methylimidazole, 2-ethyl-4-methylimidazole, 1,4-dimethylimidazole, 1,5-dimethylimidazole, 1,2,4-tri Methylimidazole, 1,4-dimethyl-2-ethylimidazole, 2-fluoroimidazole, 4-fluoroimidazole, 2-bromoimidazole, 4-bromoimidazole, 2-iodoimidazole, 4-iodoimidazole, and the like.

Specifically, it is preferred that at least one of R ¹ , R ² and R ³ is a substituted or unsubstituted C1 to C10 linear or branched alkyl compound; 1-methylimidazole, 1- is more preferable in view of productivity and price. Ethyl imidazole, 1-propylimidazole, 1-butylimidazole, 1,2-dimethylimidazole and 2-ethyl-4-methylimidazole.

The content of the imidazole compound (C) may be from about 0.001 to about 5 parts by weight based on 100 parts by weight of the (meth)acrylic copolymer (A). If the amount of the imidazole compound (C) is less than about 0.001 part by weight, the curing-promoting effect obtained after the bonding treatment may be insufficient, and a long aging time is required. If the amount of the imidazole compound (C) exceeds 5 parts by weight, the bonding strength is increased. The amount of the imidazole compound may range from about 0.001 to about 1 part by weight, preferably from about 0.015 to about 0.18 parts by weight, and more preferably from about 0.02 to about 0.15 parts by weight.

The imidazole compound (C) may be used singly or in combination of at least two. Further, the imidazole compound (C) can be obtained via synthesis or from a commercially available product.

(D) Isocyanate crosslinker

In addition to the components (A), (B), and (C), the binder composition may further include an isocyanate crosslinking agent (hereinafter also referred to as "component (D)"). When the isocyanate crosslinking agent (D) is added, the obtained adhesive layer has improved durability.

Examples of the isocyanate crosslinking agent (D) may include, but are not limited to, an aromatic diisocyanate such as triallyl isocyanate, dimer acid diisocyanate, 2,4-toluene diisocyanate (2,4-TDI), 2, 6-toluene diisocyanate (2,6-TDI), 4,4'-diphenylmethane diisocyanate (4,4'-MDI), 2,4'-diphenylmethane diisocyanate (2,4'- MDI), 1,4-phenylene diisocyanate, xylene diisocyanate (XDI), tetramethylxylene diisocyanate (TMXDI), toluidine diisocyanate (TODI) and 1,5-anaphthyl diisocyanate ( NDI); aliphatic diisocyanates such as hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate and norbornane diisocyanate (NBDI); alicyclic Diisocyanate such as trans-cyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI) and H12-MDI (hydrogenated MDI); carbon of the aforementioned diisocyanate Di-iminoimide-modified diisocyanates; or their isocyanurate-modified diisocyanates. Further, an adduct of the above isocyanate compound with a polyhydric alcohol such as trimethylolpropane or an adduct of a biuret with an isocyanate of the above isocyanate compound can be suitably used.

The isocyanate crosslinker (D) can be obtained via synthesis or from commercially available products. Commercially available products of isocyanate crosslinker (D) may include L, HL, 2030, 2031 (all available from Nippon Polyurethane Industry Co., Ltd.); D-102, D-110N, D-200, D-202 (can be obtained from ^{Mitsui Chemicals Inc.); Duranate TM 24A} -100, Duranate TM TPA-100, Duranate TM TKA-100, Duranate TM P301-75E, Duranate TM E402-90T, Duranate TM E405-80T, Duranate ^{TM TSE-100, Duranate TM D} -101 and Duranate ^TM D-201 (can be obtained from Asahi Kasei Corporation) and the like.

Specifically, it is preferred L, HL, D-110N and Duranate ^TM TPA-100; more preferred L and Duranate ^TM TPA-100. These isocyanate crosslinking agents (D) may be used singly or in combination of at least two.

The isocyanate crosslinking agent (D) may be included in an amount of from about 0.05 to about 5 parts by weight based on 100 parts by weight of the (meth)acrylic copolymer (A). Within this range, the binder composition can have suitable durability. Specifically, the isocyanate crosslinking agent may be included in an amount of from about 0.1 to about 4 parts by weight, preferably from 0.15 to about 3 parts by weight.

In addition to the above components, the binder composition may further include a decane coupling agent (hereinafter also referred to as "component (E)"). When a decane coupling agent is added, the reactivity can improve and enhance the bonding strength of the crosslinked product. Examples of the decane coupling agent may include, but are not limited to, methyltrimethoxydecane, dimethyldimethoxydecane, trimethylmethoxydecane, n-propyltrimethoxydecane, and ethyltrimethoxydecane. , diethyldiethoxydecane, n-butyltrimethoxydecane, n-hexyltriethoxydecane, n-octyltrimethoxydecane, pentyltrimethoxydecane, diphenyldimethoxydecane, Cyclohexylmethyldimethoxydecane, vinyltrichlorodecane, vinyltrimethoxydecane, vinyltriethoxydecane, vinyltris(β-methoxyethoxy)decane, β-(3 , 4-epoxycyclohexyl)ethyltrimethoxydecane, 3-glycidoxypropylmethyldiethoxydecane, γ-glycidoxypropyltrimethoxydecane, γ-glycidyl ether Oxypropyl triethoxy decane, γ-methyl propyl methoxy propyl methyl dimethoxy decane, γ-methyl propylene methoxy propyl trimethoxy decane, γ-methyl propylene oxime Propyl methyl diethoxy decane, γ-methyl propylene methoxy propyl triethoxy decane, γ-propylene decyloxy trimethoxy decane, N-β- (amino group Ethyl)-γ-aminopropylmethyldimethoxydecane, N-β-(aminoethyl)-γ-aminopropyltrimethoxydecane, N-β-(aminoethyl) - γ-aminopropyl triethoxy decane, γ-aminopropyl trimethoxy decane, γ-aminopropyl triethoxy decane, N-phenyl-γ-aminopropyltrimethoxy Decane, γ-chloropropyltrimethoxydecane, γ-mercaptopropyltrimethoxydecane, γ-mercaptopropylmethyldimethoxydecane, bis[3-(triethoxycarbinyl)propyl ] tetrasulfide, γ-isocyanatepropyltriethoxydecane, and the like. Further, a compound having a hydrolyzable formyl group via a decane coupling agent having a functional group such as an epoxy group (glycidyloxy group), an amine group, a fluorenyl group, and a (meth) acryl group can be used. A decane coupling agent having a functional group reactive with the aforementioned functional group, another coupling agent, and a polyvalent isocyanate are obtained by reacting in a certain ratio with respect to each functional group.

An oligodecane coupling agent can be used as the above decane coupling agent (E). The oligodecane coupling agent has a -Si-O-Si- structure formed by condensation of two or more decane compounds each having at least one alkoxy group. A -Si-O-Si- structure is formed in which at least one alkoxy group is bonded to one of the germanium atoms. The above oligomeric decane coupling agent has an organic functional group.

Examples of the above functional group may include a vinyl group, an epoxy group, a styryl group, a (meth) acrylonitrile group, a methacryloxy group, a propylene oxime group, an amine group, a guanidino group, a chloropropyl group, a fluorenyl group. And polysulfide groups and the like. Specifically, an epoxy group, a mercapto group, and a (meth)acrylonitrile group are preferable; in order to simultaneously obtain improved durability and low viscosity of the binder layer to be formed, a mercapto group is particularly preferable.

The oligodecane coupling agent may be an oligomer having two deuterium atoms (i.e., dimers) to about 100 deuterium atoms in one molecule, that is, an average degree of polymerization of from about 2 to about 100. The oligodecane coupling agent becomes sticky as the average degree of polymerization increases. Therefore, the oligomeric decane coupling agent may be in a slurry or solid form, which makes it difficult to handle. Accordingly, the oligomeric decane coupling agent may have an average degree of polymerization of from about 2 to about 80, preferably from about 3 to about 50.

The organofunctional group contained in the oligodecane coupling agent is usually bonded to the ruthenium atom via a suitable linking group. Examples of such a linking group may include an alkyl group such as a methylene group, an exoethyl group, a trimethylene group, a hexamethylene group, and a decamethylene group; a divalent hydrocarbon group interrupted by an aromatic ring such as methylbenzene a ethyl group; and a divalent aliphatic group interrupted by an oxygen atom, such as a methoxymethyl group, a methoxyethyl group, and a methoxypropyl group. When the organofunctional group is an epoxy group, a functional group can be formed between two adjacent carbon atoms which are ring-formed.

The above oligomeric decane coupling agent may be a co-oligomer obtained by partial co-hydrolysis and polycondensation of a tetraalkoxydecane with a decane compound represented by Formula 2:

Formula 2

Wherein R ⁴ and R ⁵ each independently represent an alkyl group or a phenyl group, X represents an organic group having a mercapto group, an epoxy group or a (meth)acryloxy group, and Y represents an alkyl group, an alkoxy group, or a phenyl group. , phenoxy, aralkyl or aralkoxy.

R ⁴ and R ⁵ in the formula 2 are independent of each other, and are, for example, a C1 to C10 alkyl group. Specifically, R ⁴ and R ⁵ may each independently be a methyl group or an ethyl group.

Examples of the organic functional group represented by X may include mercaptomethyl, 3-mercaptopropyl, 6-fluorenylhexyl, 10-mercaptodecyl, 2-(4-mercaptomethylphenyl)ethyl, glycidyl ether oxygen Methyl, 3-glycidoxypropyl, 2-(3,4-epoxycyclohexyl)ethyl, propylene methoxymethyl, 3-propenyloxypropyl, methacryl Oxymethyl group and 3-methacryloxypropyl group and the like.

Y may represent a C1 to C10 alkyl or alkoxy group or a C7 to C10 aralkyl group or an aralkyloxy group.

Examples of the functional group-containing decane compound represented by the general formula 2 may include mercaptomethyltrimethoxydecane, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, 2-(4- Mercaptomethylphenyl)ethyltrimethoxydecane, 6-fluorenylhexyltrimethoxydecane, 10-mercaptodecyltrimethoxydecane, 3-mercaptopropylmethyldimethoxydecane, 3-mercaptopropyl Methyldiethoxydecane, glycidyloxymethyltrimethoxydecane, 3-glycidoxypropyltrimethoxydecane, 2-(3,4-epoxycyclohexyl)ethyltrimethyl Oxydecane, 3-glycidyloxypropylmethyldimethoxydecane, propylene methoxymethyltrimethoxydecane, 3-propenyloxypropyltrimethoxydecane, 3-propene oxime Propyltriethoxydecane, methacryloxymethyltrimethoxydecane, 3-methylpropenyloxypropyltrimethoxydecane, 3-methylpropenyloxypropyltriethoxylate Base decane, 3-methacryloxypropyl tributoxy decane, 3-propenyl methoxy propyl methyl dimethoxy decane, 3-methyl propylene methoxy propyl methyl dimethyl Oxydecane, 3-methacryloxypropylmethyldiethoxydecane, and the like.

The tetraalkoxydecane which is partially hydrolyzed and polycondensed with the functional group-containing decane compound represented by Formula 2 has four alkoxy groups bonded to each of the ruthenium atoms. Each alkoxy group preferably has 1 to 10 carbon atoms. The four alkoxy groups bonded to the ruthenium atom may be the same or different. In terms of ease of manufacture and purchase, compounds having the same alkoxy group bonded to a ruthenium atom such as tetramethoxy decane, tetraethoxy decane, tetrapropoxy decane, and tetrabutoxy decane can be used.

The oligodecane coupling agent can be produced by partial co-hydrolysis and polycondensation of a functional group-containing decane compound represented by Formula 2 with a tetraalkoxy decane. In this case, the alkoxycarbenyl group or the phenoxymethyl sulfonyl group which is -OR ⁴ or -OR ^{5 which} is bonded to a ruthenium atom is partially hydrolyzed to form a sterol group. The alkoxycarbendanyl group of the tetraalkoxydecane is partially hydrolyzed to form a sterol group. Condensation of the two sterol groups produces an oligomeric decane coupling agent. The oligomer is preferably used because of its tendency to prevent the binder composition from being dispersed during coating and drying.

Examples of the monomeric oligodecane coupling agent are as follows.

As the co-oligomer containing a mercaptomethyl group, mercaptomethyltrimethoxydecane-tetramethoxydecane, mercaptomethyltrimethoxydecane-tetraethoxydecane, mercaptomethyltriethoxydecane can be exemplified. a tetramethoxy decane, a decylmethyltriethoxydecane-tetraethoxydecane co-oligomer or the like.

As the co-oligomer containing mercaptopropyl group, 3-mercaptopropyltrimethoxydecane-tetramethoxydecane, 3-mercaptopropyltrimethoxydecane-tetraethoxydecane, 3-mercaptopropylpropane can be exemplified. A triethoxy decane-tetramethoxy decane and a 3-mercaptopropyltriethoxy decane-tetraethoxy decane co-oligomer.

As the co-oligomer containing glycidyloxymethyl group, glycidyloxymethyltrimethoxydecane-tetramethoxydecane, glycidyloxymethyltrimethoxydecane-tetraethyl bromide can be exemplified. Oxydecane, glycidyloxymethyltriethoxydecane-tetramethoxydecane, glycidyloxymethyltriethoxydecane-tetraethoxydecane co-oligomer, and the like.

For the glycidyloxypropyl group-containing co-oligomer, 3-glycidoxypropyltrimethoxydecane-tetramethoxydecane, 3-glycidoxypropyltrimethoxy group can be exemplified.矽-tetraethoxy decane, 3-glycidoxypropyl triethoxy decane-tetramethoxy decane and 3-glycidoxy propyl triethoxy decane-tetraethoxy decane Oligomers, etc.

For the co-oligomer containing (meth) propylene methoxy propyl group, a co-oligomer containing propylene methoxy propyl group, such as 3-propenyl methoxy propyl trimethoxy decane - tetramethyl Oxydecane, 3-propenyloxypropyltrimethoxydecane-tetraethoxydecane, 3-propenyloxypropyltriethoxydecane-tetramethoxydecane, 3-propenyloxypropane Triethoxy decane-tetraethoxy decane, 3-propenyl methoxy propyl methyl dimethoxy decane-tetramethoxy decane, 3-propenyl methoxy propyl methyl dimethoxy decane -tetraethoxydecane, 3-propenyloxypropylmethyldiethoxydecane-tetramethoxydecane and 3-propenyloxypropylmethyldiethoxydecane-tetraethoxydecane Co-oligomer; co-oligomer containing methacryloxypropyl group, such as 3-methacryloxypropyltrimethoxydecane-tetramethoxydecane, 3-methylpropenyloxy Propyltrimethoxydecane-tetraethoxydecane, 3-methylpropenyloxypropyltriethoxydecane-tetramethoxydecane, 3-methylpropenyloxypropyltriethoxydecane -tetraethoxy decane, 3-methyl propylene oxime Propylmethyldimethoxydecane-tetramethoxydecane, 3-methylpropenyloxypropylmethyldimethoxydecane-tetraethoxydecane, 3-methylpropenyloxypropane A methyl-diethoxy decane-tetramethoxy decane and a 3-methacryloxypropylmethyldiethoxy decane-tetraethoxy decane co-oligomer.

The decane coupling agent can be obtained via synthesis or from commercially available products. Commercially available products that can be practically used as the above decane coupling agent include KBM-303, KBM-403, KBE-402, KBE-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802. , KBM-803, KBE-846, KBE-9007 (both available from Shin-Etsu Chemical Co., Ltd.); X-41-1805, X-41-1810, X-41-1053, and X-41-1058 (trade names, all available from Shin-Etsu Chemical Co. Ltd). X-41-1805 is an oligomeric decane coupling agent having a mercapto group, a methoxy group and an ethoxy group, and X-41-1810 is an oligomeric decane coupling agent having a mercapto group, a methyl group and a methoxy group, X-41 -1053 is an oligodecane coupling agent having an epoxy group, a methoxy group, and an ethoxy group, and X-41-1058 is an oligomeric decane coupling agent having an epoxy group, a methyl group, and a methoxy group.

Specifically, KBM-303, KBM-403, KBE-402, KBE-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, KBE-9007, X-41-1805 and X-41-1810; and more preferably KBM-403 and X-41-1810. The above decane coupling agents may be used singly or in combination of them.

The amount of the decane coupling agent is not particularly limited. Specifically, if added, the content of the decane coupling agent (E) may be from about 0.03 to about 1 part by weight, preferably from about 0.05 to about 0.5 part by weight, based on 100 parts by weight of the (meth)acrylic copolymer (A). More preferably, it is from about 0.1 to about 0.3 parts by weight. Within this range, excellent heat resistance and adhesion can be obtained.

In addition to or in place of the above-described decane coupling agent, the binder composition may include an additive. Examples of the additive include a curing accelerator, an ionic liquid, a lithium salt, an inorganic filler, a softener, an antioxidant, an anti-aging agent, a stabilizer, a tackifier resin, a reshaped resin (polyol resin, phenol resin, acrylic resin, poly Ester resin, polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, defoamer, plasticizer, dye, pigment (coloring and extender pigment), treatment agent, UV blocking Agents, fluorescent whitening agents, dispersing agents, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, lubricants and solvents. Specifically, examples of the curing accelerator may include dibutyltin dilaurate, JCS-50 (Johoku Chemical Company Ltd.), and Formate TK-1 (Mitsui Chemicals Inc.). Examples of the ionic liquid may include a material having a cation such as ruthenium, pyridinium, pyrrolidinium, imidazolium, ruthenium, ammonium, isothazide, thiourea, piperidinium, pyrazolium and ruthenium ions, and Anionic materials such as halides, nitrates, sulfates, phosphates, perchlorates, thiocyanates, thiosulfates, sulfites, tetrafluoroborates, hexafluorophosphates, formates, Oxalate, acetate, trifluoroacetate and alkyl sulfonate ions. Examples of the antioxidant may include dibutylhydroxytoluene (BT), 1010, 1035FF and 565 (both from BASF Japan Ltd.). Examples of the tackifier resin may include rosins such as abietic acid, polymerized abietic acid and rosin acid esters, anthraquinone resins, anthraquinone phenol resins, aromatic hydrocarbon resins, aliphatic saturated hydrocarbon resins, and petroleum resins. If the binder composition includes these additives, the amount of the additive is not particularly limited, but may be from about 0.1 to about 20 parts by weight based on the total amount of about 100 parts by weight of the components (A) to (C).

The adhesive composition according to the present invention can be prepared by mixing the above components one time or sequentially, or by first mixing a plurality of random components and then adding the remaining components, and stirring the components to be uniform. Specifically, the binder composition can be prepared by heating the components as needed to about 20 ° C to about 40 ° C and stirring with a stirrer for about 5 minutes to about 5 hours until the mixture becomes uniform.

The viscosity of the adhesive composition is not particularly limited. However, the binder composition may have a viscosity of from about 300 to about 7000 mPa ‧ at about 25 ° C shortly after preparation (within 10 minutes after mixing the components for a predetermined period of time) to aid in adhesion by the binder Coating and thickness control of the adhesive layer formed by the composition. For example, for an adhesive for an optical component, the adhesive composition may have a viscosity of from about 2000 to about 6000 mPa ‧ at about 25 ° C shortly after preparation (within 10 minutes after mixing the components for a predetermined period of time), A viscosity of from about 2,500 to about 5,000 mPa ‧ is preferred. For the adhesive of the surface protective film, the adhesive composition may have a viscosity of about 350 to about 5000 mPa ‧ at about 25 ° C shortly after preparation (within 10 minutes after mixing the components for a predetermined time), preferably A viscosity of from about 400 to about 4000 mPa‧s. For the adhesive of the adhesive sheet, the adhesive composition may have a viscosity of from about 350 to about 6800 mPa ‧ at about 25 ° C shortly after preparation (within 10 minutes after mixing the components for a predetermined time), preferably A viscosity of from about 400 to about 6500 mPa‧s. In the present invention, the viscosity can be measured by the method described in the following examples.

The above adhesive composition has an excellent shelf life since the excessive viscosity or gelation of the adhesive composition is controlled after preparation.

The shelf life can be evaluated by comparing the viscosity of the composition shortly after preparation of the binder composition and the viscosity of the composition about 12 hours after preparation. That is, it is preferred that the composition does not gel for about 12 hours after preparation. More preferably, the viscosity of the adhesive composition about 12 hours after preparation is increased by about 30% or less than the viscosity of the composition shortly after preparation. Within this range, the binder composition can have excellent processability.

In this context, the expression "soon after" means "within about 10 minutes." That is, "viscosity of the adhesive composition shortly after the preparation of the composition" means the viscosity of the adhesive composition measured within about 10 minutes after the preparation of the adhesive composition is completed (after a predetermined time of mixing the components).

The adhesive layer of the adhesive composition according to the present invention is obtained by crosslinking the adhesive composition. Here, the crosslinking of the binder composition is usually carried out after the application of the binder composition. However, the adhesive layer formed by the crosslinked adhesive composition can be transferred to the substrate. The binder composition can typically be crosslinked at from about 70 to about 140 ° C for from about 1 to about 5 minutes.

The adhesive layer formed from the above adhesive composition exhibits a usable adhesive property in a short aging time of about 0.5 days after the adhesion treatment (crosslinking). The practical adhesive properties of the adhesive layer can be achieved by depositing (crosslinking) the gel portion of the adhesive composition and bonding (crosslinking) at about 23 ° C and about 50% RH for about 0.5 days. The gel fraction of the adhesive composition stored at about 23 ° C and about 50% RH for about 7 days was evaluated. That is, the gel fraction after storage for about 7 days may be within ± 5% of the gel portion after storage for about 0.5 days, preferably within ± 3% of the gel portion after storage for about 0.5 days. Within this range, the binder composition can have significantly improved productivity. The above gel fraction can be measured by the method described in the following examples.

The adhesive composition can be used to bond various materials such as glass, plastic film, paper, metal foil and the like. The glass may comprise conventional inorganic glass. The plastic film plastic may include polyvinyl chloride resin, polyvinylidene chloride, cellulose resin, acrylic resin, cycloolefin resin, amorphous polyolefin resin, polyethylene, polypropylene, polystyrene, ABS resin, polyamine. , polyester, polycarbonate, polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer and chlorinated polypropylene. The amorphous polyolefin resin includes a polymer unit of a cyclic polyolefin such as norbornene or a polycyclic norbornene monomer, and may be a copolymer of a cyclic olefin and a chain-cyclic olefin. Commercial products of amorphous polyolefin resin include ATON ^TM (JSR Co., Ltd.), with (Nihon Zeon), with (Mitsui Chemicals Co., Ltd.) and the like. The amorphous polyolefin resin can be formed into a film by a suitable method known in the art such as solvent casting and melt extrusion. Further, examples of the paper may include parchment paper, raw wood-free paper, kraft paper, art coated paper, cast coated paper, calender roll paper, parchment paper, waterproof paper, cellophane, and linerboard. An example of the metal foil may include an aluminum foil.

Another embodiment of the present invention provides an optical element, a surface protective film, and an adhesive sheet comprising an adhesive layer formed from the adhesive composition according to the present invention.

Hereinafter, the application of the adhesive composition according to the present invention will be described in detail below, but is not limited thereto.

<Optical element>

The adhesive composition according to the present invention can be applied directly to one side or the opposite sides of the optical element to form a layer of adhesive. Alternatively, the adhesive layer prepared by depositing the adhesive composition on the release film in advance may be transferred to one side or the opposite side of the optical element. That is, the present invention provides an optical element comprising an adhesive layer formed from the adhesive composition according to the present invention.

Examples of the optical element may include a polarizing plate, a phase difference plate, an optical film for PDPs, a conductive film for a touch screen, and the like. Specifically, the adhesive composition of the present invention exhibits excellent adhesion to a polarizing plate and glass. However, the invention is not limited thereto, and the above binder composition can also be used for bonding other materials.

When the above binder composition is used for the adhesive layer of the optical member, the component (A) in the composition may include (a1) from about 0 to about 9 parts by weight of the carboxyl group-containing monomer, and (a2) from about 0 to About 9 parts by weight of the hydroxyl group-containing (meth)acrylic monomer and (a3) from about 82 to about 99.9 parts by weight of the (meth) acrylate monomer, and may have a weight average of from about 1,000,000 to about 2,000,000 g/mol. Molecular weight.

At this time, it should be noted that the total amount of the components (a1) and (a2) is not 0 parts by weight. That is, the (meth)acrylic copolymer (A) must include at least one of a constituent unit derived from the component (a1) and a constituent unit derived from the component (a2). Further, the total amount of the components (a1), (a2) and (a3) is about 100 parts by weight.

The amount of component (a1) of component (A) for the optical element may be from about 0 to about 8 parts by weight, preferably from about 0 to about 7.5 parts by weight, and more preferably from about 0 to about 7 parts by weight. The amount of component (a2) of component (A) used for the optical element may be from about 0 to about 4 parts by weight, preferably from about 0 to about 3.5 parts by weight, and more preferably from about 0 to about 3 parts by weight. The amount of component (a3) of component (A) used for the optical element may be from about 88 to about 99.9 parts by weight, preferably from about 89 to about 99.9 parts by weight, and more preferably from about 90 to about 99.9 parts by weight.

The total amount of component (a1) and component (a2) of component (A) for the optical element may be from about 0.1 to about 12 parts by weight, preferably from about 0.1 to about 11 parts by weight, and more preferably from about 0.1 to About 10 parts by weight.

Component (A) for the optical element may have a weight average molecular weight of from about 1,000,000 to about 1,800,000 g/mol, preferably a weight average molecular weight of from about 1,100,000 to about 1,700,000 g/mol.

The component (B) of the binder composition for an optical element may be used in an amount of from about 0.07 to about 4.5 parts by weight, preferably from about 0.1 to about 4 parts by weight, based on 100 parts by weight of the component (A).

The amount of the component (C) of the binder composition for an optical element may be from about 0.01 to about 0.5 part by weight, preferably from about 0.015 to about 0.18 part by weight, based on 100 parts by weight of the component (A), and more preferably From about 0.02 to about 0.15 parts by weight. Within this range, the adhesive composition for an optical element has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the bonding treatment, thereby remarkably improving productivity.

Also, if component (D) is present, the amount of component (D) may be from about 0.1 to about 4 parts by weight, preferably from about 0.15 to about 3 parts by weight, based on about 100 parts by weight of composition (A).

Further, for the optical element, the binder composition may further include a decane coupling agent (E). Suitable examples and suitable amounts of the decane coupling agent (F) are described above and thus will not be repeated here.

The adhesive composition for the optical element can be applied by any method known in the art, for example, using a conventional coater, a knife coater, a float knife, a roll blade coating, a knife coating, a spray coating, a dipping, a wet roll coating. Various methods such as roll coating, reverse roll coating, air knife, curtain coater, doctor blade, metal bar, die coater, comma coater, Baker applicator, and gravure coater. The thickness after coating (thickness after drying) of the adhesive composition for an optical element may be from about 5 to about 35 μm, preferably from about 15 to about 30 μm, although it may be adjusted based on materials and purposes.

When the above adhesive composition is used in an optical element, the adhesive layer has a gel portion of about 50 to about 95%, preferably about 60 to about 6, after storage for about 0.5 days at about 23 ° C and about 50% RH. 92%, more preferably from about 70 to about 90%. Within this range, optical elements with a layer of adhesive can be quickly perforated or split. In order to set the gel fraction within the above range, conditions can be appropriately selected, for example, the monomer composition of the component (A), or the amount of the component (B) or the component (C) can be adjusted according to the foregoing.

In the optical element, the adhesive layer formed in the optical element may have a bonding strength of from about 0.5 to about 9 (N/25 mm), preferably from about 1 to about 6 (N/25 mm). Within this range, advantageous reworkability can be obtained. In the present invention, the bonding strength can be measured in accordance with the test method of the pressure-sensitive adhesive tape and sheet disclosed in JIS Z0237 (2000), especially by the method described in the following examples.

The adhesive composition for optical elements has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the bonding treatment, thereby remarkably improving productivity. Further, the adhesive layer obtained from the adhesive composition for an optical element can have not only suitable bonding strength or suitable adhesion to a substrate, but also excellent metal corrosion control and prevention properties, light leakage resistance, and durability. Resistant to adherent contamination, low temperature stability and reworkability.

<Surface protective film>

The adhesive composition according to the present invention can be suitably used for a surface protective film, particularly a surface protective film for an optical element. That is, the present invention provides a surface protective film comprising an adhesive layer formed of the adhesive composition according to the present invention.

The above protective film may include any known protective film. Examples of the protective film may include a resin film such as polyethylene terephthalate, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polyester, polyvinyl chloride, polycarbonate, polyamine, and polyphenylene. A vinyl film or a composite film thereof. Specifically, a polyethylene terephthalate film can be used. Further, the protective film may have a thickness of about 15 to about 50 μm.

The adhesive layer can be formed on the protective film by directly applying the adhesive composition to the protective film, by transferring a binder composition deposited on a separate substrate (such as a release liner) or the like.

A surface protective film can be used to protect optical components that are bonded to a flat panel display panel such as an LCD or PDP. The optical element includes, for example, a polarizing plate, a phase difference plate, a brightness enhancement plate, a flash shield plate, and the like. Further, the optical element may be a laminate of at least two optical elements, such as a laminate of a polarizing plate and a phase difference plate, a laminate of a phase difference plate, a laminate of a polarizing plate and a brightness enhancement plate or a flash mask. Body and so on. Moreover, the surface protective film can be used not only as an independent optical element for distribution, but also as an optical element for dispensing a flat display panel.

When the above binder composition is used for the binder layer of the surface protective film, the component (A) contained in the composition may include (a1) from about 0 to about 9 parts by weight of the carboxyl group-containing monomer, and (a2) about 0.4 to about 9 parts by weight of the hydroxyl group-containing (meth)acrylic monomer and (a3) from about 82 to about 99.6 parts by weight of the (meth) acrylate monomer, and may have from about 100,000 to about 1,000,000 g/mol. Weight average molecular weight. Further, the total amount of the components (a1), (a2) and (a3) is about 100 parts by weight.

The amount of component (a1) of component (A) used for the surface protective film may be from about 0 to about 3 parts by weight, preferably from about 0 to about 2.5 parts by weight, and more preferably from about 0 to about 2 parts by weight. The amount of component (a2) of component (A) used for the surface protective film may be from about 0.5 to about 9 parts by weight, preferably from about 0.6 to about 9 parts by weight, and more preferably from about 0.7 to 9 parts by weight. The amount of component (a3) of component (A) used for the surface protective film may be from about 88 to about 99.5 parts by weight, preferably from about 88.5 to about 99.4 parts by weight, and more preferably from about 89 to about 99.3 parts by weight.

The total amount of the component (a1) and the component (a2) of the component (A) for the surface protective film may be from about 0.5 to about 12 parts by weight, preferably from about 0.6 to about 11.5 parts by weight, and more preferably about 0.7. Up to about 11 parts by weight.

Component (A) for the surface protective film may have a weight average molecular weight of from about 150,000 to about 950,000 g/mol, preferably a weight average molecular weight of from about 200,000 to about 900,000 g/mol.

Further, the component (B) of the binder composition for a surface protective film may be used in an amount of about 0.1 to 5 parts by weight, preferably about 0.15 to about 4.5 parts by weight, based on 100 parts by weight of the component (A). The amount of the component (C) of the binder composition for the surface protective film may be from about 0.01 to about 0.5 part by weight, preferably from about 0.015 to about 0.18 part by weight, based on 100 parts by weight of the component (A), and more It is preferably from about 0.02 to about 0.15 parts by weight. Within this range, the binder composition for the surface protective film has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the bonding treatment, thereby remarkably improving productivity. .

Further, if component (D) is used, the amount of component (D) may be from about 0.1 to about 4 parts by weight, preferably from about 0.15 to about 3 parts by weight, based on 100 parts by weight of the composition (A).

Further, for the surface protective film, the binder composition does not need to include a decane coupling agent (E).

The adhesive composition for the surface protective film can be applied by any method known in the art, for example, using a conventional coater, a knife coater, a float knife, a roll blade coat, a knife coat coating, a spray coating, a dipping, a wet roll. Various coating methods such as coating, roll coating, reverse roll coating, air knife, curtain coater, doctor blade, metal bar, die coater, comma coater, Baker applicator, and gravure coater. Specifically, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating can be used. The thickness of the adhesive composition (thickness of the adhesive layer: thickness after drying) of the adhesive composition formed on the surface protective film may be from about 3 to about 200 μm, preferably about 10, although it may be adjusted based on the material and purpose. Up to about 100 μm.

When the above binder composition is used for a surface protective film, the adhesive layer has a gel portion of about 70% to about 100%, preferably about 80, after storage for about 0.5 days at about 23 ° C and about 50% RH. From % to 99%, more preferably from about 85 to 98%. Within this range, the surface protective film having the adhesive layer can be quickly perforated or split. In order to set the gel fraction within the above range, conditions can be appropriately selected, for example, the monomer composition of the component (A), or the amount of the component (B) or the component (C) can be adjusted according to the foregoing.

In the surface protective film, the adhesive layer formed in the surface protective film may have a bonding strength of from about 0.05 to about 0.3 (N/25 mm), preferably from about 0.09 to about 0.2 (N/25 mm). Within this range, favorable resistance to adhesion by the adherend can be obtained.

The adhesive composition for a surface protective film has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the bonding treatment, thereby remarkably improving productivity. In addition, the adhesive layer obtained from the above adhesive composition can have suitable bonding strength or suitable adhesion to the substrate, as well as excellent metal corrosion control and prevention properties, resistance to adhesion contamination, low temperature stability and transparency. Sex, and control / prevent the generation of air bubbles under high temperature and high pressure conditions (during hot pressing).

<Adhesive sheet>

The adhesive composition according to the present invention can be formed into a binder layer by coating onto a substrate or a separator and drying (crosslinking), thereby preparing a sheet-like or ribbon-shaped adhesive sheet. That is, the present invention provides an adhesive sheet comprising an adhesive layer formed from the adhesive composition according to the present invention.

Examples of the substrate for the adhesive sheet may include a plastic film such as a polyester film including a polyethylene terephthalate (PET) film, a polypropylene film, and a cellophane film; plastics such as polyurethane and ethylene. - propylene terpolymer (EPT); or a variety of thin materials known in the art, such as rubber foam, paper and aluminum foil. Depending on the material, these substrates can withstand surface treatments such as corona treatment, plasma treatment and formation of layers that are easy to bond, or have an antistatic layer on the surface. Further, examples of the separator may include a plastic film for a substrate treated with ruthenium, fluorine, and a long-chain alkyl release treatment agent, or a polypropylene film not surface-treated.

When the adhesive layer is formed on the substrate, the adhesive layer may be formed on one surface of the substrate to prepare a single-sided adhesive sheet, or may be formed on each of the two surfaces to prepare a double-sided adhesive sheet. In the double-sided adhesive sheet, the adhesive composition may be formed only on one surface of the substrate, thereby preparing an adhesive tape having different adhesives on opposite sides. When the adhesive layer is formed on the separator, a double-sided adhesive sheet can be prepared.

When the above binder composition is used for the adhesive layer of the adhesive sheet, the component (A) in the composition may include (a1) from about 0 to about 9 parts by weight of the carboxyl group-containing monomer, and (a2) about 0. To about 9 parts by weight of the hydroxyl group-containing (meth)acrylic monomer and (a3) from about 82 to about 99.9 parts by weight of the (meth) acrylate monomer, and may have a weight of from about 100,000 to about 1,000,000 g/mol. Average molecular weight.

At this time, it should be noted that the total amount of the components (a1) and (a2) is not 0 parts by weight. That is, the (meth)acrylic copolymer (A) must include at least one of a constituent unit derived from the component (a1) and a constituent unit derived from the component (a2). Further, the total amount of the components (a1), (a2) and (a3) is about 100 parts by weight.

The amount of component (a1) of component (A) used for the adhesive sheet may be from about 0 to about 8 parts by weight, preferably from about 0 to about 7.5 parts by weight, and more preferably from about 0 to about 7 parts by weight. The amount of component (a2) of component (A) used for the adhesive sheet may be from about 0 to about 8 parts by weight, preferably from about 0 to about 7.5 parts by weight, and more preferably from about 0 to about 7 parts by weight. The amount of component (a3) of component (A) used for the adhesive sheet may be from about 84 to about 99.9 parts by weight, preferably from about 85 to about 99.8 parts by weight, and more preferably from about 86 to about 99.7 parts by weight.

The total amount of component (a1) and component (a2) of component (A) for the adhesive sheet may be from about 0.1 to about 16 parts by weight, preferably from about 0.2 to about 15 parts by weight, and more preferably about 0.3. Up to about 14 parts by weight.

Component (A) for the adhesive sheet may have a weight average molecular weight of from about 150,000 to about 950,000 g/mol, preferably from about 200,000 to about 900,000 g/mol.

Further, the amount of the component (B) of the binder composition for the adhesive sheet may be from about 0.07 to 4.5 parts by weight, preferably from about 0.1 to about 4 parts by weight, based on 100 parts by weight of the component (A). The component (C) of the binder composition for the adhesive sheet may be used in an amount of from about 0.01 to about 0.5 parts by weight, preferably from about 0.015 to about 0.18 parts by weight, based on 100 parts by weight of the component (A). It is preferably from about 0.02 to about 0.15 parts by weight. Within this range, the adhesive composition for the adhesive sheet has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the bonding treatment, thereby remarkably improving productivity. .

Further, if component (D) is used, the amount of component (D) may be from about 0.1 to about 4 parts by weight, preferably from about 0.15 to about 3 parts by weight, based on 100 parts by weight of the composition (A).

Further, for the adhesive sheet, the binder composition does not need to include a decane coupling agent (E).

The adhesive composition for the adhesive sheet can be applied by any method known in the art, for example, using a conventional coater, a knife coater, a float knife, a roll blade coating, a knife coating, a spray coating, a dipping, a wet roller. Various coating methods such as coating, roll coating, reverse roll coating, air knife, curtain coater, doctor blade, metal bar, die coater, comma coater, Baker applicator, and gravure coater. Specifically, roll coating, gravure coating, reverse coating, roll brushing, spray coating, air knife coating, and die coating can be used. The thickness of the adhesive composition (thickness of the adhesive layer: thickness after drying) of the adhesive composition formed on the adhesive sheet may be from about 3 to about 200 μm, preferably about 5 to 5, although it may be adjusted based on the material and purpose. About 100 μm.

When the above binder composition is used in a binder sheet, the binder layer has a gel portion of about 70% to about 100%, preferably about 80, stored at about 23 ° C and about 50% RH for about 0.5 days after the bonding treatment. From about 99%, more preferably from about 85% to about 98%. Within this range, optical elements with a layer of adhesive can be quickly perforated or split. In order to set the gel fraction within the above range, conditions can be appropriately selected, for example, the monomer composition of the component (A), or the amount of the component (B) or the component (C) can be adjusted according to the foregoing.

In the adhesive sheet, the adhesive layer formed in the adhesive sheet may have a bonding strength of from about 0.05 to about 20 (N/25 mm), preferably from about 0.1 to about 20 (N/25 mm). Within this range, the adhesive sheet can be applied as a sheet or a plurality of adhesive sheets which require a bonding strength.

The adhesive composition for the adhesive sheet has a long shelf life to obtain excellent processability, and obtains a useful adhesive property in a short aging time of about 0.5 days after the adhesive treatment, thereby remarkably improving productivity. In addition, the adhesive layer obtained from the adhesive composition for the adhesive sheet not only has suitable bonding strength or suitable adhesion to the substrate, but also has excellent metal corrosion control and prevention properties, and is resistant to adhesion by the adhesive. Properties, low temperature stability, transparency, heat resistance and moisture/heat resistance.

Example

The invention will be illustrated with reference to the following examples and comparative examples. However, it is to be understood that the invention is not limited to the illustrated embodiments and may be embodied in various different forms.

In the following examples, the solid content and viscosity of the polymer solution obtained in the Preparation Example, the viscosity of the binder composition, and the weight average molecular weight of the polymer (A) were measured by the following methods.

<solid content>

About 1 g of the polymer solution was accurately weighed on a precisely weighed glass plate. The solution was dried at 105 ° C for 1 hour and cooled to room temperature, and then the total weight of the glass plate and the remaining solid content was accurately weighed. The weight of the glass plate is defined as X, the total weight of the glass plate and the polymer solution before drying is defined as Y, the total weight of the glass plate and the remaining solid content is defined as Z, and the solid content is calculated via Equation 1:

[Equation 1]

Solid content (%) = {(Z-X) / (Y-X)} × 100

<viscosity>

The temperature of the polymer solution or binder composition in the vial was adjusted to about 25 ° C, and then the viscosity was measured using a B-type viscometer. The viscosity of the adhesive composition was measured twice shortly after preparation of the adhesive composition and 12 hours after preparation.

<weight average molecular weight>

The weight average molecular weight was measured by the following method under the following conditions shown in Table 1.

Preparation Example 1

99 parts by weight of n-butyl acrylate (Nihon Shokubai Co., Ltd.), 1 part by weight of 2-hydroxyethyl acrylate (Nihon Shokubai Co., Ltd.) and 120 parts by weight of ethyl acetate were placed in a reflux condenser and stirred. The flask was heated to 65 ° C under a nitrogen atmosphere. 0.04 part by weight of azobisisobutyronitrile (AIBN) was added, followed by polymerization while maintaining the mixture at 65 ° C for 6 hours. After the completion of the polymerization, the mixture was diluted with 280 parts by weight of ethyl acetate to obtain a solution of the polymer (A-1). The solution of the polymer (A-1) had a solid content of 20% and a viscosity of 4,500 mPa·s. Further, the polymer (A-1) has a weight average molecular weight of 1,600,000 g/mol.

Preparation Examples 2 to 19

The solutions of the polymers (A-2) to (A-19) were prepared in the same manner as in Preparation Example 1, except that the respective monomers were mixed according to the compositions listed in Table 1. Subsequently, the solid content and viscosity of the solutions of the polymers (A-2) to (A-19), and the weight average molecular weights of the polymers (A-2) to (A-19) were measured, and the results are shown in Table 2. In Table 2, "BA", "MA", "2EHA", "HEA", "4HBA", "HEAA" and "AA" refer to butyl acrylate, methyl acrylate, 2-ethyl acrylate, respectively. Ester, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, N-2-hydroxyethyl decylamine and acrylic acid.

Example 1

500 parts by weight of a solution of the polymer obtained in Preparation Example 1 (100 parts by weight of a solid polymer), and 1 part by weight of a crosslinking agent (B) as a carbodiimide (B) V-01 (B-1, Nisshinbo Chemical Co., Ltd.), 0.01 parts by weight of 1-methylimidazole (C-1, Tokyo Kasei Kogyo Co., Ltd.) as an imidazole compound (C), 0.2 parts by weight of cross-linking as isocyanate Agent (D) of Colonate (D-1, trimethylolpropane/toluene triisocyanate trimer adduct, Nippon Polyurethane Industry Co., Ltd.) and 0.1 part by weight of X-41-1810 (E-1, Shin- as a decane coupling agent) Etsu Chemical Co., Ltd.) was mixed at room temperature (25 ° C) for 10 minutes to prepare a binder composition solution.

The above solution was applied onto a PET release film (MRF38, thickness: 38 μm, Mitsubishi Polyester Film Co., Ltd.) to a dry film thickness of 25 μm, and dried at 90 ° C for 3 minutes to form a binder layer (adhesive treatment). . Subsequently, the adhesive layer is adhered to the polarizing plate to prepare a polarizing plate to which the adhesive layer adheres.

Examples 2 to 10 and Comparative Examples 1 to 9

A polarizing plate to which the adhesive composition solution and the adhesive layer adhered was prepared in the same manner as in Example 1, except that the respective polymers obtained in Preparation Examples 2 to 19, carbon bismuth, were used according to the compositions listed in Tables 4 and 5. Imine crosslinkers, imidazole compounds, isocyanate crosslinkers, decane coupling agents and other crosslinkers. B-1 and B-2, carbodiimide crosslinkers B-2 and B-3, imidazole compounds C-2, C-3 and C-4, decane coupling agents E-2, E-3 and A detailed description of E-4 and other crosslinkers F-1 is shown in Table 3.

The physical properties of the polarizing plates adhered to the adhesive layers obtained in Examples 1 to 10 and Comparative Examples 1 to 9 were evaluated as follows.

Gel part

Instead of the polarizing plates adhered according to the adhesive layers of Examples 1 to 10 and Comparative Examples 1 to 9, the adhesive layers were deposited on a belt-shaped polyester film to a dry thickness of 25 μm and subjected to a bonding treatment (crosslinking), The gel fraction was then determined after storage for 0.5 days and 7 days at 23 ° C and 50% RH. Namely, about 0.1 g of the adhesive composition placed at 23 ° C and 50% RH was weighed and defined as W ₁ (g). The composition was placed in a sample vial and about 30 g of ethyl acetate was added thereto and allowed to stand for 24 hours. After a predetermined time, the content of the bottle was passed through a 200 mesh stainless steel mesh (weight: W ₂ (g)). The web and the remaining material were dried at 90 ° C for one hour and the total weight fraction W ₃ (g) was determined. The gel fraction is calculated from Equation 2 using the measured values:

[Equation 2]

Gel part (%) = {(W _{3 -} W ₂ ) / W ₁ } x 100

2. Metal corrosion control and prevention performance

The adhesive layer of the polarizing plate adhered to each of the adhesive layers placed at 23 ° C and 50% RH for 0.5 days was adhered to the aluminum foil and left at 60 ° C and 90% RH for 2 days, followed by observation of corrosion. In Tables 4 and 5, no change is indicated as "○", and whitening is indicated as "X".

3. Anti-light leakage

The polarizing plate adhered to each adhesive layer placed at 23 ° C and 50% RH for 0.5 days was cut into 120 mm (axial (MD) direction of the polarizing plate) × 60 mm piece and 120 mm (transverse direction of the polarizing plate (TD) )))) × 60 mm piece. Each of the sheets was adhered to the opposite sides of the glass substrate, overlapped with each other, and heat-pressed at 50 ° C and 0.49 MPa (5 kg / cm ² ) for 20 minutes. Then, the glass substrate was allowed to stand at 80 ° C for 120 hours and 500 hours, and then the appearance was observed. In Tables 4 and 5, no light leakage after 120 hours and 500 hours is indicated as "?", no light leakage after 120 hours is indicated as "○", and light leakage is indicated as "X".

4. Durability

The polarizing plate adhered to each adhesive layer placed at 23 ° C and 50% RH for 7 days was cut into 120 mm (MD direction of polarizing plate) × 60 mm piece. The sheets were adhered to a glass substrate and heat-pressed at 50 ° C and 0.49 MPa (5 kg/cm ² ) for 20 minutes. Then, the glass substrate was allowed to stand at 100 ° C and 80 ° C and 90% RH for 120 hours, and then the appearance was observed. In Tables 4 and 5, no bubbles were generated, damage or peeling was indicated as "○", and generation of bubbles, damage or peeling was indicated as "X".

5. Bond strength

A polarizing plate adhered to each adhesive layer placed at 23 ° C and 50% RH for 0.5 days was cut into 25 mm wide pieces. The sheet was adhered to a glass substrate and heat-pressed at 50 ° C and 0.49 MPa (5 kg/cm ² ) for 20 minutes. According to the test method of the pressure-sensitive adhesive tape and sheet disclosed in JIS Z0237 (2000), the adhesive layer was measured at a peeling angle of 90° and a peeling rate of 0.3 m/min at 23° C./50% RH using a tensile tester. Bonding strength.

6. Adhesion to the substrate

Adhesion was evaluated while measuring the bond strength. In Tables 4 and 5, the adhesive layer was not separated from the substrate as "○", and the adhesive layer was separated from the substrate as "X".

7. Resistance to adhesion by adhesives

The contact angle of the glass substrate was measured before and after the measurement of the adhesion strength. The contact angle was measured in accordance with the test method of the wettability of the glass substrate disclosed in JIS R3257 (1999). In Tables 4 and 5, when the contact angle of the glass substrate before and after the measurement of the adhesion strength is changed to 3° or less, it is expressed as “○”, when the adhesion strength is measured before and after the measurement with the glass substrate When the contact angle changes by more than 3, it is expressed as "x".

8. Low temperature stability

The polarizing plate adhered to each adhesive layer placed at 23 ° C and 50% RH for 0.5 days was cut into 120 mm (MD direction of polarizing plate) × 60 mm piece. The sheet was adhered to a glass substrate and heat-pressed at 50 ° C and 0.49 MPa (5 kg / cm ² ) for 20 minutes. Then, the glass substrate was allowed to stand at -40 ° C for 120 hours, and then the appearance was observed. In Tables 4 and 5, no bubble generation, separation, peeling or recrystallization material was indicated as "○", and bubble generation, separation, peeling or recrystallization material was indicated as "X".

9. Reworkability

The separation state was observed while measuring the bonding strength. In Tables 4 and 5, the appearance of the interface failure is expressed as "○", and the appearance of adhesion and/or adhesion failure of the adhesive to the glass substrate (adhered matter) is expressed as "x".

The evaluation results are shown in Tables 4 and 5.

As shown in Tables 4 and 5, the binder compositions according to Examples 1 to 10 of the present invention had an excellent shelf life and a curing promoting effect as compared with the binder compositions according to Comparative Examples 1 to 9. Therefore, it is considered that the adhesive composition of the present invention remarkably improves workability and productivity. Moreover, the polarizing plates using the adhesive compositions according to Examples 1 to 10 of the present invention have excellent light leakage resistance, durability, adhesion to substrates, and resistance to being compared with the polarizing plates according to Comparative Examples 1 to 9. Adhesive contamination, low temperature stability and reworkability.

Preparation Example 20

40 parts by weight of n-butyl acrylate (Nihon Shokubai Co., Ltd.), 59 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of 2-hydroxyethyl acrylate and 150 parts by weight of ethyl acetate were placed. It was placed in a flask equipped with a reflux condenser and a stirrer and heated to 65 ° C under a nitrogen atmosphere. 0.1 part by weight of azobisisobutyronitrile (AIBN) was added, and after 1 hour, 0.05 part by weight of AIBN was further added, followed by polymerization for 6 hours while maintaining the mixture at 65 °C. After the completion of the polymerization, the mixture was diluted with 36 parts by weight of ethyl acetate, and cooled to room temperature to obtain a solution of the polymer (A-20). The solution of the polymer (A-20) had a solids content of 35% and a viscosity of 3500 mPa·s. Further, the polymer (A-20) has a weight average molecular weight of 800,000 g/mol.

Preparation Examples 21 to 39

A solution of the polymers (A-21) to (A-39) was prepared in the same manner as in Preparation Example 20 except that the respective monomers were mixed according to the compositions listed in Table 6. Subsequently, the solid content and viscosity of the solutions of the polymers (A-21) to (A-39), and the weight average molecular weights of the polymers (A-21) to (A-39) were measured, and the results are shown in Table 6. In Table 6, "BA", "2EHA", "HEA", "4HBA", "HEAA", "AA", and "AM" refer to butyl acrylate, 2-ethylhexyl acrylate, acrylic acid, respectively. 2-Hydroxyethyl ester, 4-hydroxybutyl acrylate, N-2-hydroxyethyl acrylamide, acrylic acid and acrylamide.

Example 11

286 parts by weight of a solution of the polymer obtained in Preparation Example 20 (100 parts by weight of a solid polymer), and 0.5 part by weight of a crosslinking agent (B) as a carbodiimide (B) V-01 (B-1, Nisshinbo Chemical Co., Ltd.), 0.01 part by weight of 1-methylimidazole (C-1, Tokyo Kasei Kogyo Co., Ltd.) as an imidazole compound (C), and 0.5 part by weight of isocyanate crosslinked agent (D) is ^{Duranate TM 24A-100 (D-} 2, hexamethylene diisocyanate biuret, Asahi Kasei Corporation) were mixed at room temperature (25 ℃) 10 minutes to obtain an adhesive composition solution.

The above solution was applied onto a PET release film (MRF38, thickness: 38 μm, Mitsubishi Polyester Film Co., Ltd.) to a dry film thickness of 25 μm, and dried at 90 ° C for 3 minutes to form a binder layer. Subsequently, the adhesive layer is adhered to the PET film ( S10 #25, thickness: 23 μm, Toray Industries Co., Ltd.) to prepare a surface protective film.

Examples 12 to 20 and Comparative Examples 10 to 19

A binder composition solution and a surface protective film were prepared in the same manner as in Example 11 except that the respective polymers obtained in Preparation Examples 21 to 39, carbodiimide cross-linking were used according to the compositions listed in Tables 8 and 9. Agents, imidazole compounds, isocyanate crosslinkers and other crosslinkers. As a result, surface protective films (2) to (10) and comparative surface protective films (1) to (10) were obtained. Detailed description of carbodiimide crosslinker B-3, imidazole compounds C-2, C-3 and C-4, isocyanate crosslinker D3 and other additives G-1, G-2, G-3 and G4 Shown in Table 7.

The physical properties of the surface protective films obtained according to Examples 11 to 20 and Comparative Examples 10 to 19 were evaluated as follows.

Gel part

Instead of the PET film including each of the adhesive layers according to Examples 11 to 20 and Comparative Examples 10 to 19, each adhesive layer was deposited on the peeled polyester film to a dry film thickness of 25 μm, and subjected to a bonding treatment (crosslinking). The gel fraction was then measured after storage for 0.5 days and 7 days at 23 ° C and 50% RH. Namely, about 0.1 g of the adhesive composition placed at 23 ° C and 50% RH was weighed and defined as W ₁ (g). This composition was placed in a sample vial, about 30 g of ethyl acetate was added thereto and left for 24 hours. After the predetermined time, the contents of the bottle were filtered through a 200 mesh stainless steel mesh (weight: W ₂ (g)). The web and the remaining material were dried at 90 ° C for 1 hour, and the total weight W ₃ (g) was determined. The gel fraction is calculated from Equation 2 using the measured values:

[Equation 2]

The gel fraction (%) = {(W _{3 -} W ₂ ) / W ₁ } x 100.

2. Metal corrosion control and prevention performance

The adhesive layer of each surface protective film after being left for 0.5 day at 23 ° C and 50% RH was adhered to an aluminum foil and left at 60 ° C and 90% RH for 2 days, followed by observation of corrosion. In Tables 8 and 9, no change is indicated as "○", and whitening is indicated as "X".

3. Bond strength

Each surface protective film after leaving it at 23 ° C and 50% RH for 0.5 days was cut into pieces of 25 mm width. The sheet was adhered to a polarizing plate and heat-pressed at 50 ° C and 0.49 MPa (5 kg/cm ² ) for 20 minutes. According to the test method of the pressure-sensitive adhesive tape and sheet disclosed in JIS Z0237 (2000), the adhesive layer was measured at a peeling angle of 180° and a peeling rate of 0.3 m/min at 23° C./50% RH using a tensile tester. Bonding strength.

4. Adhesion to the substrate

The adhesion to each protective film (substrate) was evaluated while measuring the adhesion strength. In Tables 8 and 9, the adhesive layer was not separated from the substrate as "○", and the adhesive layer was separated from the substrate as "X".

5. Resistance to adhesion by adhesives

The contact angle of the polarizing plate was measured before and after the measurement of the adhesion strength. The contact angle was measured in accordance with the test method of the wettability of the glass substrate disclosed in JIS R3257 (1999). In Tables 8 and 9, when the contact angle of the polarizing plate changes by 3 or less before and after the measurement of the adhesive strength, it is expressed as "○", and the contact angle with the polarizing plate before and after the measurement of the bonding strength is shown. When the change is greater than 3°, it is expressed as “×”.

6. Low temperature stability

Each surface protective film after being left for 0.5 days at 23 ° C and 50% RH was adhered to a polarizing plate and heat-pressed at 50 ° C and 0.49 MPa (5 kg/cm ² ) for 20 minutes. Subsequently, the polarizing plate was allowed to stand at -40 ° C for 120 hours, and then the appearance was observed. In Tables 8 and 9, the material which did not generate bubbles, was separated, peeled off or recrystallized was denoted as "○", and the material which produced bubbles, separation, peeling or recrystallization was expressed as "X".

7. Transparency of the adhesive layer

The surface protective film after 0.5 day at 23 ° C and 50% RH was observed with the naked eye to confirm the transparency of the adhesive film. In Tables 8 and 9, suitable transparency is indicated as "○", and white turbidity of the adhesive layer is indicated as "X".

8. Suitability for hot pressing treatment

Each surface protective film after leaving it at 23 ° C and 50% RH for 0.5 days was cut into pieces of 25 mm width. The sheet was adhered to a polarizing plate, and heat-pressed at 50 ° C and 0.49 MPa (5 kg / cm ² ) for 20 minutes, and then air bubbles were observed. In Tables 8 and 9, the bubble generation is indicated as "○", and the bubble generation is indicated as "X".

The evaluation results are shown in Tables 8 and 9.

As shown in Tables 8 and 9, the binder compositions according to Examples 11 to 20 of the present invention had an excellent shelf life and a curing promoting effect as compared with the binder compositions according to Comparative Examples 10 to 19. Therefore, it is considered that the adhesive composition of the present invention remarkably improves workability and productivity. Further, the surface protective films according to Examples 11 to 20 of the present invention have excellent adhesion to a substrate, contamination against adherends, low-temperature stability, and an adhesive layer as compared with the polarizing plates of Comparative Examples 10 to 19. Transparency and suitability for hot pressing treatment.

Preparation Example 40

40 parts by weight of n-butyl acrylate (Nihon Shokubai Co., Ltd.), 59 parts by weight of 2-ethylhexyl acrylate, 1 part by weight of 2-hydroxyethyl acrylate and 150 parts by weight of ethyl acetate were placed. It was placed in a flask equipped with a reflux condenser and a stirrer and heated to 65 ° C under a nitrogen atmosphere. 0.1 part by weight of azobisisobutyronitrile (AIBN) was added, and after 1 hour, 0.05 part by weight of AIBN was further added, followed by polymerization for 6 hours while maintaining the mixture at 65 °C. After the completion of the polymerization, the mixture was diluted with 36 parts by weight of ethyl acetate, and cooled to room temperature to obtain a solution of the polymer (A-40). The solution of the polymer (A-40) had a solids content of 35% and a viscosity of 3500 mPa·s. Further, the polymer (A-40) has a weight average molecular weight of 800,000 g/mol.

Preparation Examples 41 to 59

A solution of the polymers (A-41) to (A-59) was prepared in the same manner as in Preparation 40 except that the respective monomers were mixed according to the compositions listed in Table 10. Subsequently, the solid content and viscosity of the solutions of the polymers (A-41) to (A-59), and the weight average molecular weights of the polymers (A-41) to (A-59) were measured, and the results are shown in Table 10. In Table 10, "BA", "2EHA", "VAc", "HEA", "4HBA", "HEAA", "AA", and "AM" refer to butyl acrylate, 2-ethyl acrylate, respectively. Ester, vinyl acetate, 2-hydroxyethyl acrylate, 4-hydroxybutyl acrylate, N-2-hydroxyethyl acrylamide, acrylic acid and acrylamide.

Example 21

286 parts by weight of a solution of the polymer obtained in Preparation Example 40 (100 parts by weight of a solid polymer), 0.3 parts by weight of a crosslinking agent (B) as a carbodiimide (B) V-01 (B-1, Nisshinbo Chemical Co., Ltd.), 0.01 parts by weight of 1-methylimidazole (C-1, Tokyo Kasei Kogyo Co., Ltd.) as an imidazole compound (C), and 0.2 part by weight of isocyanate crosslinked agent (D) is ^{Duranate TM 24A-100 (D-} 2, hexamethylene diisocyanate biuret, Asahi Kasei Corporation) were mixed at room temperature (25 ℃) 10 minutes to obtain an adhesive composition solution.

This solution was applied onto a PET release film (MRF38, thickness: 38 μm, Mitsubishi Polyester Film Co., Ltd.) to a dry film thickness of 25 μm, and dried at 90 ° C for 3 minutes to form a binder layer. Subsequently, the adhesive layer is adhered to the PET film ( S10 #25, thickness: 23 μm, Toray Industries, Inc., to prepare a binder sheet (1).

Examples 22 to 30 and Comparative Examples 20 to 29

A binder composition solution and a binder sheet were prepared in the same manner as in Example 21 except that the respective polymers obtained in Preparation Examples 41 to 59, carbodiimide crosslinked according to the compositions listed in Table 12 and Table 13 were used. Agents, imidazole compounds, isocyanate crosslinkers and other crosslinkers. As a result, the adhesive sheets (2) to (10) and the comparative adhesive sheets (1) to (10) were obtained. Carbopolonitrile crosslinkers B-2 and B-3, imidazole compounds C-2, C-3 and C-4, isocyanate crosslinker D-3 and other crosslinkers G-1, G-2, A detailed description of G-3 and G-4 is shown in Table 11.

The physical properties of the adhesive sheets obtained according to Examples 21 to 30 and Comparative Examples 20 to 29 were evaluated as follows.

Gel part

The gel fraction was measured in the same manner as in Examples 11 to 20 and Comparative Examples 10 to 19.

2. Metal corrosion control and prevention performance

The adhesive layer of each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was adhered to an aluminum foil and left at 60 ° C and 90% RH for 2 days, followed by observation of corrosion. In Tables 12 and 13, no change is indicated as "○", and whitening is indicated as "X".

3. Bond strength

Each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was cut into 25 mm wide pieces. The sheet was pressed onto a stainless steel plate, reciprocated once with a 2 kg roller, and placed at 23 ° C and 50% RH for 20 minutes. Then, according to the test method of the pressure-sensitive adhesive tape and sheet disclosed in JIS Z0237 (2000), the adhesion was measured at a peeling angle of 180° and a peeling rate of 0.3 m/min at 23° C./50% RH using a tensile tester. Connection strength.

4. Adhesion to the substrate

The adhesion to each adhesive sheet (substrate) was evaluated while measuring the adhesive strength. In Tables 12 and 13, the adhesive layer was not separated from the substrate as "○", and the adhesive layer and the substrate were separated as "X".

5. Resistance to adhesion by adhesives

The contact angle of the stainless steel plate was measured before and after the measurement of the adhesion strength. The contact angle was measured in accordance with the test method of the wettability of the glass substrate disclosed in JIS R3257 (1999). In Tables 12 and 13, when the contact angle of the stainless steel plate before and after the measurement of the adhesive strength was changed to 3 or less, it was expressed as "○", and the contact angle of the stainless steel plate was changed before and after the measurement of the adhesive strength. When it is larger than 3°, it is expressed as “×”.

6. Low temperature stability

Each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was pressed onto a stainless steel plate, reciprocated once with a 2 kg roller, and left at 23 ° C and 50% RH for 1 hour. Subsequently, the stainless steel plate was allowed to stand at -40 ° C for 120 hours, and then the appearance was observed. In Tables 12 and 13, the material which did not generate bubbles, was separated, peeled off or recrystallized was denoted as "○", and the material which produced bubbles, separation, peeling or recrystallization was expressed as "X".

7. Transparency of the adhesive layer

Each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was visually observed to confirm the transparency of the adhesive film. In Tables 12 and 13, suitable transparency is indicated as "○", and white turbidity of the adhesive layer is indicated as "X".

8. Heat resistance

Each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was pressed onto a stainless steel plate, reciprocated once with a 2 kg roller, and left at 23 ° C and 50% RH for 1 hour. Subsequently, the stainless steel plate was allowed to stand at 80 ° C for 500 hours, and then the appearance was observed. In Tables 12 and 13, bubbles were not present, separation or peeling was indicated as "○", and bubbles, separation or peeling were indicated as "X".

9. Moisture resistance / heat resistance

Each of the adhesive sheets placed at 23 ° C and 50% RH for 0.5 days was pressed onto a stainless steel plate, reciprocated once with a 2 kg roller, and left at 23 ° C and 50% RH for 1 hour. Subsequently, the stainless steel plate was allowed to stand at 60 ° C and 90% RH for 500 hours, and then the appearance was observed. In Tables 12 and 13, bubbles were not present, separation or peeling was indicated as "○", and bubbles, separation or peeling were indicated as "X".

The evaluation results are shown in Table 12 and Table 13.

As shown in Table 12 and Table 13, the binder compositions according to Examples 21 to 30 of the present invention had an excellent shelf life and a curing promoting effect as compared with the binder compositions according to Comparative Examples 20 to 29. Therefore, it is considered that the adhesive composition of the present invention remarkably improves workability and productivity. Further, the adhesive sheets according to Examples 21 to 30 of the present invention have excellent adhesion to a substrate, contamination against adherends, low-temperature stability, and an adhesive as compared with the adhesive sheets of Comparative Examples 20 to 29. The transparency, heat resistance and moisture/heat resistance of the layer.

Although a few embodiments have been disclosed herein, it is understood that these embodiments are provided by way of illustration only, and various modifications, changes and changes may be made without departing from the spirit and scope of the invention. Therefore, the scope of the invention is to be limited only by the scope of the appended claims and their equivalents.

Claims (13)

A binder composition comprising: (A) 100 parts by weight of a (meth)acrylic copolymer having a weight average molecular weight of 150,000 to 950,000 g/mol; (B) 0.05 to 5 parts by weight of a carbodiimide crosslink And (C) 0.001 to 5 parts by weight of the imidazole compound represented by Formula 1: In the formula 1, R ¹ , R ² and R ³ each independently represent a hydrogen atom, a halogen atom or a substituted or unsubstituted C1 to C10 linear or branched alkyl group; the binder composition is used for preparation The adhesive layer of the surface protective film; and the adhesive layer has a bonding strength of 0.05 to 0.3 N/25 mm measured according to JIS Z0237. The adhesive composition according to claim 1, wherein the (meth)acrylic copolymer (A) comprises (a1) 0 to 9 parts by weight of a carboxyl group-containing monomer, and (a2) 0 to 9 by weight. a hydroxyl group-containing (meth)acrylic monomer and (a3) 82 to 99.9 parts by weight of a (meth) acrylate monomer, the carboxyl group-containing monomer (a1) and the hydroxyl group-containing (meth) group The total amount of the acrylic monomer (a2) is not 0 parts by weight, and the carboxyl group-containing monomer (a1), the hydroxyl group-containing (meth)acrylic monomer (a2), and the (meth) acrylate The total amount of the monomer (a3) was 100 parts by weight. The adhesive composition of claim 1, which further comprises 0.05 to 5 parts by weight of the isocyanate crosslinking agent (D) based on 100 parts by weight of the (meth)acrylic copolymer (A). The adhesive composition of claim 1, further comprising a decane coupling agent. An optical element comprising an adhesive layer formed of the adhesive composition according to any one of claims 1 to 4. The optical element according to claim 5, wherein the (meth)acrylic copolymer (A) has a weight average molecular weight of from 1,000,000 to 1,800,000 g/mol, and the adhesive layer has a density of 0.5 to JIS Z0237. 9N/25mm bonding strength. The optical component of claim 5, wherein the adhesive layer has 50% to 95% after the adhesive composition is formed into a binder layer and left at 23 ° C and 50% RH for 0.5 days. The gel part. A surface protective film comprising an adhesive layer formed of the adhesive composition according to any one of claims 1 to 3. The surface protective film of claim 8, wherein the (meth)acrylic copolymer (A) has a weight average molecular weight of from 150,000 to 900,000 g/mol, and the adhesive layer has a weight of 0.05 according to JIS Z0237. Bonding strength to 0.3N/25mm. The surface protective film of claim 8, wherein the adhesive layer has 70% to 100 after the adhesive composition is formed into a binder layer and left at 23 ° C and 50% RH for 0.5 days. % gel part. An adhesive sheet comprising any one of items 1 to 3 of the patent application scope A layer of adhesive formed by the adhesive composition. The adhesive sheet of claim 11, wherein the (meth)acrylic copolymer (A) has a weight average molecular weight of 150,000 to 950,000 g/mol, and the adhesive layer has 0.05 according to JIS Z0237. Bond strength to 20N/25mm. The adhesive sheet of claim 11, wherein the adhesive layer has 70% to 100 after the adhesive composition is formed into a binder layer and left at 23 ° C and 50% RH for 0.5 days. % gel part.