KR101716197B1 - Adhesive layer and adhesive film - Google Patents

Abstract

The present invention provides a pressure-sensitive adhesive layer having both a high adhesive force and a high adhesive property, and a pressure-sensitive adhesive film using the pressure-sensitive adhesive layer, despite the thin film having a thickness of 1 탆 to 20 탆. A pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition comprising an acryl-based polymer, wherein the acrylic polymer is a pressure-sensitive adhesive layer comprising at least one alkyl (meth) acrylate monomer having an alkyl group having a C1- As the other copolymerizable monomer, at least one or more vinyl monomers having a nitrogen atom and at least one copolymerizable vinyl monomer having a hydroxyl group, wherein the crosslinking agent is Trifunctional isocyanate compound, and the pressure-sensitive adhesive layer has a thickness of 1 占 퐉 to 20 占 퐉 and a thickness of 20 占 퐉, the initial cohesive adhesive strength is 3.0 (N / 25mm) or more, and the refractive index is 1.47 to 1.50.

Description

[0001] ADHESIVE LAYER AND ADHESIVE FILM [0002]

The present invention relates to a pressure-sensitive adhesive layer and a pressure-sensitive adhesive film used for interlaminar bonding of an optical member and the like. More particularly, the present invention relates to a pressure-sensitive adhesive layer having a high adhesive force and a high adhesion performance despite a thin film having a thickness of 1 탆 to 20 탆 and an adhesive film using the pressure-sensitive adhesive layer.

A variety of pressure-sensitive adhesive films have been proposed in order to bond an optical member such as a polarizing plate and a phase difference plate to an adherend such as a liquid crystal cell via a pressure-sensitive adhesive layer (see, for example, Patent Documents 1 and 2).

Patent Document 1 discloses a pressure-sensitive adhesive composition for optical use which comprises butyl acrylate or the like as a main component monomer and contains an acrylamide compound or the like.

Patent Document 2 discloses a pressure-sensitive adhesive composition for optical use which contains a (meth) acrylate having an alkyl group of 4 to 8 carbon atoms as a main component monomer and a monomer having a carboxyl group and a vinyl monomer having a nitrogen atom.

Adhesive films have been proposed in order to increase the refractive index of the pressure-sensitive adhesive layer (see, for example, Patent Documents 3 to 8).

Patent Document 3 discloses an optical adhesive composition having an aromatic ring and containing a tackifier having a refractive index of 1.51 to 1.75.

Patent Document 4 discloses a pressure-sensitive adhesive sheet containing a pressure-sensitive adhesive composition comprising a copolymerized polymer of an acrylic acid-modified monomer having an aromatic ring.

Patent Document 5 discloses a pressure-sensitive adhesive composition for optical purposes containing a tackifier resin having aromatic rings and an aromatic phosphate ester plasticizer.

Patent Document 6 discloses a pressure-sensitive adhesive comprising a pressure-sensitive adhesive composition comprising an acrylic resin and an aromatic compound having one ethylenic unsaturated group cured.

Patent Document 7 describes an optical component obtained by fixing a retardation film and a birefringent plate to each other through an acrylic pressure sensitive adhesive containing an aromatic monomer.

Patent Document 8 discloses a pressure-sensitive adhesive composition comprising a urethane resin obtained by reacting an aromatic diisocyanate and an aromatic polyester diol.

Japanese Laid-Open Patent Publication No. 2012-177022 Japanese Laid-Open Patent Publication No. 2012-201734 Japanese Patent Application Laid-Open No. 2007-084762 Japanese Laid-Open Patent Publication No. 2011-153169 Japanese Laid-Open Patent Publication No. 2012-167188 Japanese Laid-Open Patent Publication No. 2012-021148 Japanese Laid-Open Patent Publication No. 2006-293281 Japanese Laid-Open Patent Publication No. 2009-091522

BACKGROUND ART In recent years, what is required of an adhesive film used for bonding an interlayer of an optical member is an adhesive film in which the thickness of the adhesive layer is reduced to 20 占 퐉 or less in order to reduce the thickness of the optical member.

Generally, since the adhesive force of the pressure-sensitive adhesive layer is approximately proportional to the thickness of the pressure-sensitive adhesive layer, when the thickness of the pressure-sensitive adhesive layer is made thinner, adherence is deteriorated.

However, in recent years, a pressure-sensitive adhesive film which is required to have a pressure-sensitive adhesive force equivalent to that of a conventional pressure-sensitive adhesive film (thickness of the pressure-sensitive adhesive layer is about 30 탆 thick) It is required to have a performance equal to or higher than that of the conventional adhesive film.

In addition, from the viewpoint that a thickness of the pressure-sensitive adhesive layer can be made thin and a pressure-sensitive adhesive layer which does not need to be subjected to an aging treatment (curing at a constant temperature) can be formed, only the pressure- (Release film / pressure-sensitive adhesive layer / releasing film) ", which is a constituent member of the " release film / pressure-sensitive adhesive layer / release film "

In addition, in the conventional adhesive film, since the adhesive film is subjected to the aging treatment after the adhesive film is applied to the adherend, adhesion between the adherend and the pressure-sensitive adhesive layer can be improved.

However, since the adhesive film in the form of NCF already has completed the aging of the pressure-sensitive adhesive layer, adhesion between the adherend and the pressure-sensitive adhesive layer becomes insufficient. For this reason, there has been a problem in that it is necessary to perform surface treatment such as corona treatment on the surface of the adherend.

There is a need for an adhesive film that overcomes these requirements and problems.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a pressure-sensitive adhesive layer having a high adhesive force and a high adhesion performance despite a thin film having a thickness of 1 탆 to 20 탆 and an adhesive film using the same.

In order to solve the above problems, the present invention provides a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition comprising an acrylic polymer, wherein at least one of alkyl (meth) acrylate monomers having an alkyl group having from 1 to 14 carbon atoms is used as a main component monomer, The pressure-sensitive adhesive layer contains at least one or more vinyl monomers having a copolymerizable nitrogen atom as other copolymerizable monomers and is copolymerized and crosslinked to obtain a pressure-sensitive adhesive layer having both a strong adhesion and a high adhesion.

Further, in order to solve the above problems, the present invention provides a pressure-sensitive adhesive layer comprising a pressure-sensitive adhesive composition comprising an acrylic polymer, wherein the pressure-sensitive adhesive layer comprises a (meth) acrylate monomer in which the acrylic polymer is a main component, (Meth) acrylate monomer having at least one aromatic group and at least one or more kinds of vinyl monomers having at least one kind of (meth) acrylate monomer having an aromatic group and having nitrogen atoms as other copolymerizable monomers, Wherein the cross-linking agent for crosslinking the pressure-sensitive adhesive composition is a trifunctional isocyanate compound, the thickness of the pressure-sensitive adhesive layer is 1 占 퐉 to 20 占 퐉, the thickness of the pressure-sensitive adhesive layer is 20 占 퐉 (N / 25 mm) or more and a refractive index of 1.47 to 1.50 when the pressure-sensitive adhesive layer .

(A) 70 to 95 parts by weight of an alkyl (meth) acrylate monomer having at least one C1 to C14 alkyl group, and (B) at least one (meth) acrylate having an aromatic group (C) 2 to 50 parts by weight of at least one vinyl monomer having a nitrogen atom, (D) at least one vinyl monomer having a hydroxyl group, A copolymer of 0.1 to 10 parts by weight of at least one kind of synthetic vinyl monomer and a weight average molecular weight of 200,000 to 200,000, and (E) 0.001 to 1 part by weight of a trifunctional isocyanate compound.

Further, it is preferable that the acryl-based polymer does not contain a copolymerizable vinyl monomer having a carboxyl group as its monomer.

It is also preferable that the gel fraction of the pressure-sensitive adhesive layer is 50 to 70%.

Further, containing parts of 25~50 ℃ melting point ionic compound 0.1 to 5.0 parts by weight in the pressure-sensitive adhesive composition, it is preferable that the surface resistivity of the pressure-sensitive adhesive layer 5.0 × 10 ⁺¹⁰ Ω / □ or less.

Further, the present invention provides an adhesive film characterized in that the pressure-sensitive adhesive layer is formed on one side of a release film and is a constitution of a release film / pressure-sensitive adhesive layer / release film.

Further, the present invention provides an adhesive film characterized in that the pressure-sensitive adhesive layer is laminated on one side of a substrate.

Further, the present invention provides a film used for bonding a polarizing plate and a display panel using the above-mentioned pressure-sensitive adhesive film.

The present invention also provides a film for a touch panel using an adhesive film.

The present invention also provides an electron species utilizing film using the above adhesive film.

Further, the present invention provides an optical film having a pressure-sensitive adhesive layer formed by laminating the pressure-sensitive adhesive layer on at least one surface of an optical film.

According to the present invention, it is possible to provide a pressure-sensitive adhesive layer having a high adhesive force and a high adhesion performance despite the thin film having a thickness of 1 탆 to 20 탆 and the pressure-sensitive adhesive film using the same, overcoming the conventional requirements and problems.

Hereinafter, the present invention will be described based on preferred embodiments.

The pressure-sensitive adhesive layer of the present invention is a pressure-sensitive adhesive layer formed by crosslinking a pressure-sensitive adhesive composition comprising an acrylic polymer, wherein the (meth) acrylate monomer having an alkyl group of C1- (Meth) acrylate monomer having at least one aromatic group and at least one or more kinds of vinyl monomers having nitrogen atoms as other copolymerizable monomers and at least one kind of vinyl monomer having a nitrogen atom, Wherein the crosslinking agent for crosslinking the pressure-sensitive adhesive composition is a trifunctional isocyanate compound, the thickness of the pressure-sensitive adhesive layer is 1 占 퐉 to 20 占 퐉, and the thickness is 20 占 퐉 An initial adhesive strength of 3.0 (N / 25 mm) or more, and a refractive index of 1.47 to 1.50.

In the present specification, the description of the fact that the acrylic polymer (copolymer) contains (contains) a monomer means that mainly the monomer is copolymerized in the acrylic polymer (copolymer), but a part of the raw monomer is an acrylic polymer ), The remaining unreacted material is not excluded.

Examples of the alkyl (meth) acrylate monomer having an alkyl group of C1 to C14 include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) (Meth) acrylate, isobutyl (meth) acrylate, pentyl (meth) acrylate, hexyl (meth) acrylate, (Meth) acrylate, nonyl (meth) acrylate, nonyl (meth) acrylate, isononyl (meth) acrylate, decyl (Meth) acrylate, tetradecyl (meth) acrylate, cyclopentyl (meth) acrylate, cyclohexyl (meth) acrylate and the like. The alkyl group of the alkyl (meth) acrylate monomer may be any of linear, branched and cyclic. (A) the alkyl (meth) acrylate monomer in which the alkyl group has from 1 to 14 carbon atoms is preferably 70 to 95 parts by weight based on 100 parts by weight of the (meth) acrylate monomer having an aromatic group and (B) Do.

Examples of the (meth) acrylate monomer having an aromatic group include benzyl (meth) acrylate, naphthyl (meth) acrylate, phenoxyethyl (meth) acrylate, phenoxybutyl Naphthyloxy) ethyl (meth) acrylate, 2- (2-naphthyloxy) ethyl (meth) acrylate, 6- (Meth) acrylate, 8- (1-naphthyloxy) octyl (meth) acrylate, ) Acrylate, and polyethylene glycol o-phenyl phenyl ether (meth) acrylate. In order to obtain a pressure-sensitive adhesive layer having a high refractive index, it is preferable to blend at least one or more (meth) acrylate monomers having an aromatic group.

(Meth) acrylate monomer having an aromatic group is mixed with an alkyl (meth) acrylate monomer having a C1-C14 carbon number of an alkyl group as a main component monomer, the refractive index of the obtained pressure sensitive adhesive layer can be raised and adjusted, The total light transmission can be improved by reducing the total reflection.

In the pressure-sensitive adhesive layer according to the present invention, the (meth) acrylate monomer (B) having an aromatic group may be used in an amount of 5 to 30 parts by weight per 100 parts by weight of the (meth) By weight.

Examples of the vinyl monomer having a nitrogen atom include cyclic nitrogen vinyl compounds such as N-vinylpyrrolidone, N-vinylcaprolactam and (meth) acryloylmorpholine, N-ethyl- (Meth) acrylamide, N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide Substituted (meth) acrylamides such as acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide and N, N-dibutyl (Meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N-methyl-N-propylaminoethyl (Meth) acrylate, N, N-dimethylaminoethyl (meth) acrylate, N, N-dimethylaminopropyl (meth) (Meth) acrylates such as N, N-dipropylaminoethyl (meth) acrylate and N, N-dibutylaminoethyl (meth) (Meth) acrylamide, N, N-dimethylaminopropyl (meth) acrylamide, N-methyl-N-isopropylaminopropyl , N, N-diethylaminopropyl (meth) acrylamide, N, N-dipropylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (Meth) acrylamide, and dialkyl-substituted aminoalkyl (meth) acrylamides such as (meth) acrylamide.

The vinyl monomer having a nitrogen atom preferably has no hydroxyl group in order to be distinguishable from the compound (D) to be described later, and more preferably has no hydroxyl group and no carboxyl group. Examples of such a monomer include acrylic monomers having the above-exemplified monomers such as N, N-dialkyl substituted amino groups and N, N-dialkyl substituted amide groups; N-vinyl substituted lactams such as N-vinyl pyrrolidone and N-vinyl caprolactam; And N- (meth) acryloyl-substituted cyclic amines such as N- (meth) acryloylmorpholine.

Further, in the pressure-sensitive adhesive layer according to the present invention, the nitrogen-containing vinyl monomer contained in the acrylic polymer of the pressure-sensitive adhesive composition can impart necessary adhesive strength and durability to the pressure-sensitive adhesive layer. In the pressure-sensitive adhesive layer according to the present invention, the vinyl monomer having a nitrogen atom contained in the acrylic polymer of the pressure-sensitive adhesive composition is preferably 2 (meth) acrylate based on 100 parts by weight of the (meth) To 50 parts by weight.

Examples of the vinyl monomer having a nitrogen atom contained in the acrylic polymer of the pressure-sensitive adhesive composition of the present invention include N-vinylpyrrolidone, N, N-dimethyl (meth) acrylamide, N, N (Meth) acrylamide, N, N-dipropyl (meth) acrylamide, N, N-diisopropyl N, N-dimethylaminopropyl (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylamide and N-vinylcaprolactam are particularly preferably used.

Examples of the copolymerizable vinyl monomer having a hydroxyl group (monomer having a hydroxyl group) include 8-hydroxyoctyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 4-hydroxybutyl (Meth) acrylates such as hydroxyethyl (meth) acrylate and hydroxyethyl (meth) acrylate, hydroxyalkyl (meth) acrylates such as N-hydroxy (Meth) acrylamides having a hydroxyl group such as hydroxyethyl (meth) acrylamide, and the like.

In the pressure-sensitive adhesive layer according to the present invention, the monomer having a hydroxyl group contained in the acrylic polymer of the pressure-sensitive adhesive composition is preferably an acrylic pressure-sensitive adhesive composition in which the pressure-sensitive adhesive layer to be obtained has an influence on the corrosiveness to an adherend, Can be used as a copolymerizable monomer for reducing the content of a monomer having a carboxyl group which is considered to give a carboxyl group. Therefore, the monomer having a hydroxyl group can be usefully used for improving the adhesive strength of the pressure-sensitive adhesive layer and also for reducing the corrosiveness. In the pressure-sensitive adhesive layer according to the present invention, the monomer having a hydroxyl group contained in the acrylic polymer of the pressure-sensitive adhesive composition is preferably 0.1 to 100 parts by weight of the (meth) acrylate monomer which is the main component containing the component (A) To 10 parts by weight.

The copolymer of the pressure-sensitive adhesive composition used in the pressure-sensitive adhesive layer of the present invention comprises (A) 70 to 95 parts by weight of at least one alkyl (meth) acrylate monomer having an alkyl group having from 1 to 14 carbon atoms, (C) 2 to 50 parts by weight of at least one vinyl monomer having a nitrogen atom, and (C) at least one compound selected from the group consisting of (meth) acrylate monomer having an aromatic group D) 0.1 to 10 parts by weight of at least one copolymerizable vinyl monomer having a hydroxyl group.

Further, it is preferable that the acryl-based polymer does not contain a copolymerizable vinyl monomer having a carboxyl group as its monomer. When the polymer has a carboxyl group, there is a fear that an adherend such as ITO is corroded by an acid.

The polymerization method of the copolymer is not particularly limited, and a well-known polymerization method such as a solution polymerization method or an emulsion polymerization method can be used. The weight average molecular weight of the copolymer is preferably 200,000 to 200,000.

The copolymer is preferably an acrylic polymer, and it is preferable that the copolymer contains 50 to 100% by weight of an acrylic monomer such as (meth) acrylic acid ester monomer or (meth) acrylamide.

The gel fraction of the pressure-sensitive adhesive layer is preferably 50 to 70%.

The pressure-sensitive adhesive composition can adjust properties such as required physical properties by blending a crosslinking agent or an optional additive with the copolymer.

Examples of the crosslinking agent include biuret-modified or isocyanurate-modified products of diisocyanates such as hexamethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, tolylene diisocyanate and xylylene diisocyanate, trimethylol (E) trifunctional isocyanate compounds such as adducts with tri- or higher-valent polyols such as propane or glycerin are preferable.

Examples of the trifunctional isocyanate compound include an isocyanurate of a hexamethylene diisocyanate compound, an isocyanurate of an isophorone diisocyanate compound, an adduct of a hexamethylene diisocyanate compound, and an adduct of an isophorone diisocyanate compound , A burette of a hexamethylene diisocyanate compound, a burette of an isophorone diisocyanate compound, an isocyanurate of a tolylene diisocyanate compound, an isocyanurate of a xylylene diisocyanate compound, an isocyanurate of a xylenylene diisocyanate compound A cyanurate, an adduct of a tolylene diisocyanate compound, an adduct of a xylylene diisocyanate compound, and an adduct of a hydrogenated xylylene diisocyanate compound.

In the case of crosslinking a copolymer using a trifunctional isocyanate compound, it is preferable that the copolymer has a functional group (in particular, a hydroxyl group) capable of performing a crosslinking reaction with a crosslinking agent, and that the copolymer contains a monomer having such a functional group in its side chain desirable. It is also preferable that the pressure-sensitive adhesive composition contains 0.001 to 1 part by weight of (E) trifunctional isocyanate compound as a crosslinking agent. The criteria for the parts by weight are the same as (A) to (D) in the copolymer.

The pressure-sensitive adhesive composition of the present invention may contain an antistatic agent to impart an antistatic property. The antistatic agent is preferably a solid at ordinary temperature (for example, 25 占 폚), and more specifically, the antistatic agent is an ionic compound having a melting point of 25 to 50 占 폚. The antistatic agent may be a quaternary ammonium salt type ionic compound having an acryloyl group.

Since these antistatic agents have a low melting point and also have a long chain alkyl group, it is presumed that the affinity with the acrylic polymer is high.

When the antistatic property is imparted, it is preferable that the pressure-sensitive adhesive layer formed by crosslinking the pressure-sensitive adhesive composition has a surface resistivity of 5.0 x 10 < ⁺¹⁰ >

As the antistatic agent which is an ionic compound having a melting point of 25 to 50 占 폚, an ionic compound having a cation and an anion, wherein the cation is a pyridinium cation, imidazolium cation, pyrimidinium cation, pyrazolium cation, (PF ₆ ^- ), thiocyanate (SCN ^- ), alkyl (meth) acrylate, and the like can be used as the anion. Compounds which are inorganic or organic anions such as benzenesulfonate (RC ₆ H ₄ SO ₃ ^- ), perchlorate (ClO ₄ ^- ) and tetrafluoroborate (BF ₄ ^- ). Depending on the chain length of the alkyl group, the position of the substituent, the number of the substituents, etc., a melting point of 25 to 50 占 폚 can be obtained. The cation is preferably a quaternary ammonium onium cation, a quaternary pyridinium cation or a quaternary pyridinium cation such as 1-alkyl pyridinium (the carbon atom at 2-6 may have a substituent or may be unsubstituted) Quaternary imidazolium cation such as 3-dialkyl imidazolium (the carbon atom at the 2, 4 and 5 positions may have a substituent or may be unsubstituted), quaternary ammonium cation such as tetraalkylammonium and the like .

As the quaternary ammonium salt type ionic compound having an acryloyl group, an ionic compound having a cation and an anion, wherein the cation is a (meth) acryloyloxyalkyltrialkylammonium [R ₃ N ⁺ -C _n H _2n - (PF ₆ ^- ), thiocyanate (SCN ^- CH ₂ ), quaternary ammonium having a (meth) acryloyl group such as OCOCQ = CH ₂ wherein Q = H or CH ₃ , ), Organic sulfonate (RSO ₃ ^- ), perchlorate (ClO ₄ ^- ), tetrafluoroborate (BF ₄ ^- ) and imide salt with fluorine atom (R ^F ₂ N ^- . Already deuyeom (R ^F ₂ N ^-) has a fluorine atom roneun of R ^F, can be given as a trifluoromethanesulfonyl group, a pentafluorophenyl perfluoroalkyl ethane sulfonyl group, such as an alkane sulfonyl group or a fluoroalkyl sulfonyl group. As already it deuyeom having a fluorine atom include bis (fluoro sulfonyl) already deuyeom [(FSO _{2) 2} N ^-], bis (trifluoromethane sulfonyl) already deuyeom _{[(CF 3 SO 2) 2 N} - ] , Bis (pentafluoroethanesulfonyl) imide salt [(C ₂ F ₅ SO ₂ ) ₂ N ^- ], and the like.

The antistatic agent which is an ionic compound having a melting point of 25 to 50 占 폚 is not particularly limited. Specific examples of the ionic compound having a pyridinium cation and having a melting point of 25 to 50 캜 include 1-octylpyridinium dodecylbenzenesulfonate, 1-dodecylpyridinium thiocyanate, 3-methyl-1-dodec Dodecylpyridinium dodecylbenzenesulfonate, 4-methyl-1-octylpyridinium hexafluorophosphate, and the like.

Specific examples of the quaternary ammonium salt type ionic compound having an acryloyl group include dimethylaminomethyl (meth) acrylate hexafluorophosphate salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ PF ^_6, with the proviso that, Q = H or CH _3], dimethylaminoethyl (meth) imide methyl salt acrylate, bis (trifluoromethane sulfonyl) ^{_{[(CH 3) 3 N + (}} CH 2) 2 OCOCQ = CH ₂ (CF ₃ SO ₂ ) ₂ N ^- , where Q = H or CH ₃ , dimethylaminomethyl (meth) acrylate bis (fluorosulfonyl) imide methyl salt [(CH ₃ ) ₃ N ⁺ CH ₂ OCOCQ = CH ₂ (FSO ₂ ) ₂ N ^- , where Q = H or CH ₃ ].

The ionic compound having a melting point of 25 to 50 DEG C is preferably contained in an amount of 0.1 to 5.0 parts by weight based on 100 parts by weight of the (meth) acrylate monomer as the main component including the above (A) and (B) .

When the pressure-sensitive adhesive composition of the present invention is used for the application of an optical member to a display panel or the like, it is preferable to add a silane coupling agent. Examples of the silane coupling agent to be added include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, 3-methacryloxypropyltrimethoxysilane, 3-methacryloxypropyltri Methacryloxypropylmethyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, vinyltriacetoxysilane, 3-acryloxypropyltrimethoxysilane, 3-acryloxypropyltriethoxy Silane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 2- (3 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3- Mercaptopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane Aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, 3-isocyanatepropyltrimethoxysilane and 3-isocyanatepropyltriethoxysilane. have. These silane coupling agents may be used alone or in combination of two or more. The addition amount is preferably 0.001 to 5 parts by weight, based on 100 parts by weight of the pressure-sensitive adhesive composition.

Known other additives such as antioxidants, surfactants, curing accelerators, plasticizers, fillers, crosslinking catalysts, crosslinking retarders, curing retarders, processing aids and antioxidants can be appropriately added as optional components. These may be used alone or in combination of two or more.

The pressure-sensitive adhesive layer of the present invention can be obtained by applying the pressure-sensitive adhesive composition to a substrate or a release film, and then crosslinking the pressure-sensitive adhesive composition.

When the optical member is used for layer-to-layer bonding or the like, it is preferable that the pressure-sensitive adhesive layer is a thin pressure-sensitive adhesive layer, and the thickness of the pressure-sensitive adhesive layer is preferably 1 m to 20 m. In general, the adhesive force of the pressure-sensitive adhesive layer is approximately proportional to the thickness of the pressure-sensitive adhesive layer, but it is preferable that the initial adhesive force when the thickness is 20 m is 3.0 (N / 25 mm) or more.

When the pressure-sensitive adhesive layer of the present invention is applied to, for example, a polarizing plate (polarizing film) as an optical member, it is preferable that the adhesive force to the polarizing plate is not less than the lower limit described above. In general, a polarizing film is mainly composed of a polyvinyl alcohol (PVA) film on which iodine is adsorbed, and a protective layer such as triacetyl cellulose (TAC) or polyethylene terephthalate (PET) saponified on its surface is formed . Here, it is preferable that the pressure-sensitive adhesive layer of the present invention has an adhesive strength to an adherend such as saponified triacetyl cellulose (TAC) of not less than the lower limit described above.

When the pressure-sensitive adhesive layer according to the present invention is used for layer-to-layer bonding of optical members, it is preferable that the refractive index difference is as small as possible in order to reduce reflection of light rays at the interface between the pressure-sensitive adhesive layer and the optical member. Therefore, the refractive index of the pressure-sensitive adhesive layer is preferably 1.47 to 1.50.

The pressure-sensitive adhesive film of the present invention can be produced by forming the pressure-sensitive adhesive layer of the present invention on one side of a substrate or a release film.

As the base film used for forming the pressure-sensitive adhesive layer or the release film (separator) for protecting the pressure-sensitive adhesive surface, a resin film such as a polyester film or the like can be used.

Antistatic treatment with an antifouling treatment with a silicon-based or fluorine-based releasing agent, a coating agent, fine silica particles, antistatic treatment by application or incorporation of an antistatic agent, etc. can be performed on the surface of the base film opposite to the side where the pressure-

The release film is subjected to releasing treatment by a silicone-based, fluorine-based releasing agent or the like on the side of the pressure-sensitive adhesive layer which is to be brought into contact with the adhesive surface.

The release film, the pressure-sensitive adhesive layer, and the release film may be formed on both surfaces of one pressure-sensitive adhesive layer by aligning the surfaces subjected to the release treatment of the release film. In this case, the releasing films on both sides are sequentially or simultaneously peeled off to expose the adhesive surface, so that the releasing film can be bonded to an optical member such as an optical film. Examples of the optical film include a polarizing film, a retardation film, an antireflection film, an antiglare film, an ultraviolet absorbing film, an infrared absorbing film, an optical compensating film, and a brightness improving film.

The pressure-sensitive adhesive film of the present invention can be used for bonding a polarizing plate and a display panel. Examples of the display panel include a liquid crystal display, an organic EL, and the like, but are not limited thereto.

Further, the pressure-sensitive adhesive film of the present invention can be applied to various types of optical films for peripheral members of a liquid crystal display device mainly including a polarizing plate, various optical films for a touch panel, various optical films for electronic species, various optical films for organic EL, .

Further, the optical film may be an optical film having a pressure-sensitive adhesive layer formed by laminating the pressure-sensitive adhesive layer on at least one surface of these optical films. Specifically, the optical film / pressure-sensitive adhesive layer / optical film, the optical film / pressure-sensitive adhesive layer / release film, the optical film / pressure-sensitive adhesive layer, , "Optical film / pressure-sensitive adhesive layer / optical film / pressure-sensitive adhesive layer / release film", "release film / pressure-sensitive adhesive layer / optical film / pressure-sensitive adhesive layer / release film".

For example, in the case of having a pressure-sensitive adhesive layer protected with a release film such as "optical film / pressure-sensitive adhesive layer / release film", the release film is peeled off to expose the pressure-sensitive adhesive layer like "optical film / pressure- By the conjugation, a configuration similar to that of the "optical film / pressure-sensitive adhesive layer / optical film" in which the pressure-sensitive adhesive layer is used for interlayer bonding is obtained.

Example

Hereinafter, the present invention will be described in detail by way of examples.

≪ Preparation of acrylic copolymer >

[Example 1]

Nitrogen gas was introduced into a reactor equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube to replace the air in the reactor with nitrogen gas. Thereafter, 90 parts by weight of butyl acrylate, 10 parts by weight of benzyl acrylate, 10 parts by weight of N-vinylpyrrolidone, 2.5 parts by weight of 6-hydroxyhexyl acrylate, and a solvent (ethyl acetate) . Thereafter, 0.1 part by weight of azobisisobutyronitrile as a polymerization initiator was added dropwise over 2 hours and reacted at 65 DEG C for 6 hours to obtain an acrylic copolymer solution (1) used in Example 1 having a weight average molecular weight of 500,000 . A part of the acrylic copolymer was sampled and used as a measurement sample of the acid value described later.

[Examples 2 to 5 and Comparative Examples 1 to 3]

Examples 2 to 5 and Comparative Example 1 were prepared in the same manner as in the acrylic copolymer solution (1) used in Example 1 except that the composition of the monomers was changed as shown in Table 1 (A) to (D) To obtain an acrylic copolymer solution used in Examples 1-3. Further, although the measurement results are not particularly shown, the weight average molecular weights of the copolymers contained in the acrylic copolymer solutions of Examples 2 to 5 and Comparative Examples 1 to 3 are within the range of 200,000 to 2,000,000.

≪ Preparation of pressure-sensitive adhesive composition, pressure-sensitive adhesive layer and pressure-

[Example 1]

0.5 part by weight of Coronate HX (isocyanurate compound of hexamethylene diisocyanate compound) was added to the acrylic copolymer solution (1) of Example 1 thus prepared, and the mixture was stirred and mixed to obtain the pressure-sensitive adhesive composition of Example 1 . This pressure-sensitive adhesive composition was coated on a release film made of a polyethylene terephthalate (PET) film coated with a silicone resin and dried at 90 DEG C to remove the solvent and then aged for 7 days under an atmosphere of 23 DEG C and 50% RH to obtain a pressure- To obtain the pressure-sensitive adhesive film of Example 1 having a pressure-sensitive adhesive layer formed by crosslinking on one side of the release film.

[Examples 2 to 5 and Comparative Examples 1 to 3]

The pressure-sensitive adhesive films of Examples 2 to 5 and Comparative Examples 1 to 3 were obtained in the same manner as the pressure-sensitive adhesive films of Example 1 except that the compositions of the additives were changed to those of (E) and (F) .

In Table 1, numerical values in parts by weight are enclosed in parentheses as the addition ratios of the groups (C) to (F) obtained by dividing the sum of the groups (A) and (B) by 100 parts by weight. In Example 3, the total of the groups (A) and (B) was 110 parts by weight. In Example 5, the total of the groups (A) and ) Group and (C) group is set to 100 parts by weight.

Table 2 shows the chemical names of the weak symbols of each component used in Table 1. < tb > < TABLE > On the other hand, Coronate (registered trademark) HX, HL and L-45 are trade names of Nippon Polyurethane Industry Co., Ltd. and D-110N is a trade name of Mitsui Chemicals, HDI means hexamethylene diisocyanate, TDI means tolylene diisocyanate, and XDI means xylylene diisocyanate.

<Test Method and Evaluation>

A release film (PET film coated with a silicone resin) was peeled from the pressure-sensitive adhesive films in Examples 1 to 5 and Comparative Examples 1 to 3 to expose the pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer was transferred to one side of the polarizer (film).

&Lt; Measurement method of adhesive force &gt;

The pressure-sensitive adhesive layer was transferred onto one side of a polarizing plate (film) having a thickness of 180 占 퐉 to obtain a pressure-sensitive adhesive film (optical film on which a pressure-sensitive adhesive layer was formed) serving as a sample.

The pressure-sensitive adhesive film was bonded to a non-asbestos surface washed with acetone of soda lime glass with a compression roll, autoclaved under the conditions of 50 占 폚 and 0.5 MPa 占 20 minutes, then returned under an atmosphere of 23 占 폚 占 50% RH, The peel strength of the adhesive film after that was measured by a tensile tester in accordance with JIS Z0237 &quot; Test Method for Adhesive Tape / Adhesive Sheet &quot;, and peeled off at a rate of 300 mm / min in the direction of 180 deg. And the adhesive strength of the pressure-sensitive adhesive layer.

<Gel fraction>

After the completion of the aging, the mass of the sample to be measured before the application to the polarizing plate is precisely measured, and after soaking in toluene for 24 hours, the glass is filtered through a 200-mesh wire net. Thereafter, the filtrate was dried at 100 DEG C for 1 hour, and the mass of the residue was accurately measured. From the following equation, the gel fraction of the pressure-sensitive adhesive layer (pressure-sensitive adhesive after crosslinking) was calculated.

Gel fraction (%) = Insoluble part mass (g) / Adhesive mass (g) × 100

&Lt; Test method of adhesion &gt;

The pressure-sensitive adhesive layer of the pressure-sensitive adhesive film as a sample after the measurement of the pressure-sensitive adhesive force was visually confirmed, and adhesion was judged by the state of being separated from the polarizing plate (film) of the base layer.

○ ... The pressure-sensitive adhesive layer is not completely removed from the substrate layer.

△ ... The pressure-sensitive adhesive layer partially falls from the substrate layer.

× ... The pressure-sensitive adhesive layer is detached from the base layer and is electrodeposited on the glass as the adherend.

<Workability>

A 10 cm square adhesive film produced in the same manner as in the measurement of adhesive strength was stuck to a non-asbestos surface of soda lime glass in the same manner, and the sample was allowed to stand at 70 DEG C for 24 hours under the atmosphere of DRY, The adhesive residue on the surface of the adherend when the adhesive film was peeled off from the glass plate was visually observed.

○ ... The adhesive residue is not identified at all.

△ ... A small amount of adhesive residue was identified.

× ... The adhesive residue was clearly identified.

<Test method of durability>

A sample prepared by sticking an adhesive film of 10 cm square on the non-asbestos surface of soda lime glass in the same manner as in the measurement of the adhesive force was left for 250 hours in an atmosphere of 60 캜 x 90% RH, × 50% RH atmosphere. After 1 hour, the state of the adhesive film was visually observed to determine the durability.

○ ... There is no peeling or foaming of the adhesive film at all.

△ ... Peeling and foaming are generated on a part of the adhesive film.

× ... Peeling and foaming are generated in the whole of the adhesive film.

<Method of measuring refractive index>

The refractive index of the pressure-sensitive adhesive layer at 23 캜 is measured with an Abbe refractometer (manufacturer: ERMA, model: ER-2S).

&Lt; Method of measuring surface resistivity &

After aging, a release film (PET resin film coated with a silicone resin) was peeled off to form a pressure-sensitive adhesive layer, and the pressure-sensitive adhesive layer was exposed using a resistivity meter HILESTA UP-HT450 (manufactured by Mitsubishi Chemical Polytechnic) The surface resistivity was measured.

Table 3 shows the evaluation results. In addition, the surface resistivity is represented by a method of "m × 10 ^{+ n} " being "mE + n" (where m is an arbitrary real number and n is a positive integer).

The pressure-sensitive adhesive films of Examples 1 to 5 had an initial adhesive strength of 3.0 N / 25 mm or more and a refractive index of the pressure-sensitive adhesive layer within a range of 1.47 to 1.50, and were excellent in adhesiveness, reworkability and durability . That is, the requirements and problems in the adhesive films of Examples 1 to 5 were overcome. Further, in the pressure-sensitive adhesive film of Example 3-5 has a surface resistivity of sufficient 5.0 × 10 ⁺¹⁰ Ω / □ or less to have an antistatic property.

The pressure-sensitive adhesive film of Comparative Example 1 had a high gel fraction and an initial pressure-sensitive adhesive strength of a pressure-sensitive adhesive layer having a thickness of 20 占 퐉. Further, since the (meth) acrylate monomer having an aromatic group is not contained, the refractive index of the pressure-sensitive adhesive layer is low. Further, adhesion and durability were also deteriorated.

The pressure-sensitive adhesive film of Comparative Example 2 had a low gel fraction and a poor adhesive force of the pressure-sensitive adhesive layer having a thickness of 5 占 퐉. Further, since the (meth) acrylate monomer having an aromatic group is not contained, the refractive index of the pressure-sensitive adhesive layer is low. Further, adhesion, reworkability and durability were also deteriorated.

The adhesive film of Comparative Example 3 had a low gel fraction, and had poor reworkability and durability.

Thus, the adhesive films of Comparative Examples 1 to 3 can not overcome the conventional requirements and problems.

Claims (11)

A pressure-sensitive adhesive layer formed by crosslinking a pressure-sensitive adhesive composition containing an acrylic polymer,
The acrylic polymer
(A) 70 to 95 parts by weight of at least one alkyl (meth) acrylate monomer having an alkyl group having from 1 to 14 carbon atoms,
And 5 to 30 parts by weight of at least one (meth) acrylate monomer having an aromatic group (B), based on 100 parts by weight of the total of
As other copolymerizable monomers
(C) 2 to 50 parts by weight of a vinyl monomer having at least one nitrogen atom,
(D) 0.1 to 10 parts by weight of at least one copolymerizable vinyl monomer having a hydroxyl group
A copolymer having a weight average molecular weight of 200,000 to 2,000,000 which is copolymerized without containing a copolymerizable monomer having a carboxyl group,
Wherein the crosslinking agent for crosslinking the pressure-sensitive adhesive composition is a trifunctional isocyanate compound, the pressure-sensitive adhesive layer has a thickness of 1 占 퐉 to 20 占 퐉 and a thickness of 20 占 퐉, and the initial cohesive strength is 3.0 (N / 25mm) Is 1.47 to 1.50,
Wherein the pressure-sensitive adhesive layer has a gel fraction of 50 to 70%. delete delete delete The method according to claim 1,
Contains parts of 25~50 ℃ melting point ionic compound 0.1 to 5.0 parts by weight in the pressure-sensitive adhesive composition and the surface resistivity of the pressure-sensitive adhesive layer 5.0 × 10 ⁺¹⁰ Ω / □ or less pressure-sensitive adhesive layer. The pressure-sensitive adhesive film according to claim 1, wherein the pressure-sensitive adhesive layer is formed on one side of the release film, and the release film / pressure-sensitive adhesive layer / release film. A pressure-sensitive adhesive film comprising the pressure-sensitive adhesive layer of claim 1 laminated on one side of a substrate. delete delete delete An optical film comprising a pressure-sensitive adhesive layer formed by laminating the pressure-sensitive adhesive layer of claim 1 on at least one surface of an optical film.