JP5463023B2 - Adhesive composition and optical member using the same - Google Patents

Description

  The present invention relates to an adhesive composition and an optical member using the same. More specifically, the present invention relates to a pressure-sensitive adhesive composition excellent in heat resistance and flexibility and an optical member using the same.

  Recently, the use of flat panel displays (FPD) such as liquid crystal display devices (LCD), plasma displays (PDP), and organic EL devices has been expanded. In connection with this, the improvement of the heat resistance and reworkability (removability) of the adhesive used for FPD is calculated | required. In addition, when an adhesive is used in an LCD, characteristics that prevent light leakage due to contraction of the polarizing plate have been demanded.

Here, Patent Document 1 discloses a pressure-sensitive adhesive composition obtained by mixing an isocyanate compound, a polyol compound, and a silane compound having an epoxy group in an acrylic resin.
Japanese Patent No. 3846912

  However, the pressure-sensitive adhesive composition described in Patent Document 1 has a problem that when the amount of the curing agent is small, crosslinking of the polymer contained is insufficient and the heat resistance deteriorates, and when the amount of the curing agent is large, the crosslinking structure is rigid. For this reason, the cohesive strength and adhesive strength of the pressure-sensitive adhesive are increased, but the flexibility is poor, and the light leakage resistance and reworkability are poor.

  This invention is made | formed in view of the said situation, The objective is to provide the adhesive composition excellent in heat resistance and a softness | flexibility.

  The present inventors have intensively studied to solve the above problems. As a result, it has been found that a pressure-sensitive adhesive composition containing a (meth) acrylic polymer having a hydroxy group and a polycarbonate diol exhibits excellent heat resistance and flexibility, and has completed the present invention.

  That is, the present invention includes (a-1) 99.5 to 80 parts by mass of a (meth) acrylate monomer, (a-2) 0.5 to 10 parts by mass of a hydroxy group-containing (meth) acrylic monomer, and (a -3) 0-10 parts by mass of other monomers copolymerizable with the above (a-1) and (a-2) (however, the total amount of (a-1) to (a-3) is 100 parts by mass) Is a pressure-sensitive adhesive composition containing a hydroxy group-containing (meth) acrylic polymer (A), an isocyanate curing agent (B), and a polycarbonate diol (C).

  The pressure-sensitive adhesive composition of the present invention is excellent in heat resistance and flexibility. Therefore, the pressure-sensitive adhesive composition of the present invention is effective for adhesion of adherends such as various plastic films, and particularly when used for a polarizing plate, excellent light leakage resistance and reworkability can be obtained.

  The present invention includes (a-1) 99.5 to 80 parts by mass of a (meth) acrylate monomer, (a-2) 0.5 to 10 parts by mass of a hydroxy group-containing (meth) acrylic monomer, and (a-3) ) 0-10 parts by mass of other monomers copolymerizable with (a-1) and (a-2) (however, the total amount of (a-1) to (a-3) is 100 parts by mass) A pressure-sensitive adhesive composition comprising a hydroxy group-containing (meth) acrylic polymer (A), an isocyanate curing agent (B), and a polycarbonate diol (C).

  FIG. 1 is a schematic diagram showing a cross-linked structure of a conventional pressure-sensitive adhesive composition containing an acrylic resin 1, an isocyanate curing agent 2, and a polyol 3 typified by Patent Document 1. As shown in FIG. 1, the isocyanate curing agent 2 reacts preferentially with the polyol 3 and hardly reacts with the acrylic resin 1. Therefore, when there are few isocyanate hardening agents 2, there exists a problem that bridge | crosslinking of acrylic resin 1 does not advance and heat resistance falls. Moreover, when there are many isocyanate type hardening | curing agents 2, since crosslinking of the polyol 3 and the isocyanate type hardening | curing agent 2 advances excessively, there exists a possibility that adhesive itself may gelatinize. Furthermore, since the cross-linked structure is rigid, the cohesive force of the pressure-sensitive adhesive is increased, but the flexibility is poor, and the light leakage resistance is poor.

  On the other hand, FIG. 2 is a schematic diagram showing a crosslinked structure of the pressure-sensitive adhesive composition of the present invention. In the pressure-sensitive adhesive composition of the present invention, as shown in FIG. 2, the isocyanate curing agent B reacts with and binds to the hydroxy group and the polycarbonate diol C in the hydroxy group-containing (meth) acrylic polymer A to form a crosslinked structure. Form. Therefore, since the polycarbonate diol C is introduced into the crosslinked structure and the molecular weight between the crosslinking points is increased, the pressure-sensitive adhesive composition of the present invention has excellent heat resistance and flexibility. Due to such heat resistance and flexibility, the pressure-sensitive adhesive composition of the present invention can follow the contraction of the polarizing plate, and, for example, peels off or floats of the polarizing plate from the liquid crystal cell substrate even under a high temperature and wet heat environment. It is excellent in adhesion. In particular, when used for a polarizing plate, it is excellent in light leakage resistance and reworkability.

  Hereinafter, each component of the pressure-sensitive adhesive composition of the present invention will be described in detail. In the present specification, “(meth) acrylate” is a general term for acrylate and methacrylate. Similarly, a compound containing (meth) such as (meth) acrylic acid is a general term for a compound having “meta” in the name and a compound not having “meta”.

(A) Hydroxy group-containing (meth) acrylic polymer (A) Hydroxy group-containing (meth) acrylic polymer (hereinafter also simply referred to as “component (A)”) used in the present invention is (a-1) ( A (meth) acrylate monomer, (a-2) a hydroxy group-containing (meth) acrylic monomer, and (a-3) other monomer copolymerizable with (a-1) and (a-2). Polymerized.

  (A-1) A (meth) acrylate monomer (hereinafter, also simply referred to as “component (a-1)”) is an ester of (meth) acrylic acid having no hydroxy group in the molecule. Specific examples of the component (a-1) include, for example, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl ( (Meth) acrylate, tert-butyl (meth) acrylate, isoamyl (meth) acrylate, n-hexyl (meth) acrylate, n-heptyl (meth) acrylate, n-octyl (meth) acrylate, tert-octyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, decyl (meth) acrylate, isodecyl (meth) acrylate, tridecyl (meth) acrylate, stearyl (meth) acrylate, isostearyl (meth) acrylate, phenyl (meth) acrylate , Benzyl (meth) acrylate, dodecyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, cyclohexyl (meth) acrylate, 4-n-butylcyclohexyl (meth) acrylate, 2-ethylhexyl diglycol (meth) acrylate, butoxyethyl (Meth) acrylate, butoxymethyl (meth) acrylate, 3-methoxybutyl (meth) acrylate, 2- (2-methoxyethoxy) ethyl (meth) acrylate, 2- (2-butoxyethoxy) ethyl (meth) acrylate, 4 -Butylphenyl (meth) acrylate, phenyl (meth) acrylate, 2,4,5-tetramethylphenyl (meth) acrylate, phenoxymethyl (meth) acrylate, phenoxyethyl (meth) acrylate , Polyethylene oxide monoalkyl ether (meth) acrylate, polyethylene oxide monoalkyl ether (meth) acrylate, polypropylene oxide monoalkyl ether (meth) acrylate, trifluoroethyl (meth) acrylate, pentadecafluorooxyethyl (meth) acrylate, 2 -Chloroethyl (meth) acrylate, 2,3-dibromopropyl (meth) acrylate, tribromophenyl (meth) acrylate and the like. These components (a-1) may be used alone or in combination of two or more.

  Among these components (a-1), methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, and tert-butyl acrylate are preferable, methyl acrylate, ethyl acrylate, and n-butyl acrylate are more preferable, and methyl acrylate, n- Butyl acrylate is particularly preferred.

  The usage-amount of a component (a-1) is 99.5-80 mass parts by making the total amount of a component (a-1)-(a-3) 100 mass parts, and 99.2-88.0 mass. Part is preferable, and 99.0 to 93.0 parts by mass is more preferable.

  (A-2) A hydroxy group-containing (meth) acrylic monomer (hereinafter also simply referred to as “component (a-2)”) is an acrylic monomer having a hydroxy group in the molecule. Specific examples of the component (a-2) include, for example, 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 1,6-hexanediol mono (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-phenyloxypropyl (meth) acrylate, 4-hydroxycyclohexyl (meth) acrylate, 2-hydroxyethylacrylamide, cyclohexane dimethyl Nord monoacrylate, and the like, further, alkyl glycidyl ether, allyl glycidyl ether, and a glycidyl group-containing compounds such as glycidyl (meth) acrylate, and compounds obtained by addition reaction of (meth) acrylic acid. These components (a-2) may be used alone or in combination of two or more.

  Among these components (a-2), 2-hydroxyethyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxyethylacrylamide, and cyclohexanedimethanol monoacrylate are preferable, and 2-hydroxyethyl (meth) acrylate 4-hydroxybutyl (meth) acrylate and 2-hydroxyethyl acrylamide are more preferable, and 2-hydroxyethyl acrylate and 2-hydroxyethyl acrylamide are particularly preferable.

  The usage-amount of a component (a-2) is 0.5-10 mass parts by making the total amount of a component (a-1)-(a-3) into 100 mass parts, and is 0.6-7 mass parts. It is preferable that it is 0.7 to 5 parts by mass. If it exists in said range, the crosslinking point which the hydroxyl group derived from the component (a-2) in a polymer (A) and an isocyanate type hardening | curing agent (B) react will not become excessive, and the adhesion of this invention The agent composition has excellent heat resistance and flexibility.

  If necessary, other monomer copolymerizable with component (a-1) and component (a-2) (hereinafter also simply referred to as “component (a-3)”) is used. The component (a-3) is not particularly limited. Specific examples of the component (a-3) include, for example, acrylic monomers having an epoxy group such as glycidyl (meth) acrylate and methylglycidyl (meth) acrylate; dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) ) Acrylic monomers having amino groups such as acrylate, N-tert-butylaminoethyl (meth) acrylate, methacryloxyethyltrimethylammonium chloride (meth) acrylate; (meth) acrylamide, N-methylol (meth) acrylamide, N- Acrylic monomers having amide groups such as methoxymethyl (meth) acrylamide, N, N-methylenebis (meth) acrylamide; (meth) acrylic acid, 2-methacryloyloxysuccinic acid, 2-methacryloylo Acrylic monomers having a carboxyl group such as cythyl maleic acid, 2-methacryloyloxyethyl phthalic acid, 2-methacryloyloxyethyl hexahydrophthalic acid; 2-methacryloyloxyethyl diphenyl phosphate (meth) acrylate, trimethacryloyloxyethyl phosphate ( Acrylic monomers having a phosphate group such as meth) acrylate and triacryloyloxyethyl phosphate (meth) acrylate; sulfopropyl (meth) acrylate sodium, 2-sulfoethyl (meth) acrylate sodium, 2-acrylamido-2-methylpropanesulfone Acrylic monomers having a sulfonic acid group such as sodium acid; acrylic monomers having a urethane group such as urethane (meth) acrylate; p- acrylic vinyl monomers having a phenyl group such as ert-butylphenyl (meth) acrylate and o-biphenyl (meth) acrylate; 2-acetoacetoxyethyl (meth) acrylate, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris ( β-methoxyethyl) silane, vinyltriacetylsilane, methacryloyloxypropyltrimethoxysilane and other vinyl monomers having silane groups; styrene, chlorostyrene, α-methylstyrene, vinyltoluene, vinyl chloride, vinyl acetate, vinyl propionate, acrylonitrile Vinyl pyridine and the like. These components (a-3) may be used alone or in combination of two or more.

  Among these components (a-3), (meth) acrylic acid, (meth) acrylamide, glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate, 2-acetoacetoxyethyl (meth) acrylate are preferable, and (meth) Acrylic acid, acrylamide, dimethylaminoethyl (meth) acrylate, and 2-acetoacetoxyethyl (meth) acrylate are more preferable, and acrylic acid is particularly preferable.

  The usage-amount of a component (a-3) is 0-10 mass parts by making the total amount of a component (a-1)-(a-3) into 100 mass parts, and shall be 0.2-5 mass parts. Is preferable, and it is more preferable that it is 0.3-2 mass parts.

  The production method of the hydroxy group-containing (meth) acrylic polymer (A) is not particularly limited, and is a solution polymerization method using a polymerization initiator, an emulsion polymerization method, a suspension polymerization method, a reverse phase suspension polymerization method, a thin film weight. Conventionally known methods such as a combination method and a spray polymerization method can be used. Examples of the polymerization control method include adiabatic polymerization, temperature controlled polymerization, and isothermal polymerization. In addition to the method of initiating polymerization with a polymerization initiator, a method of initiating polymerization by irradiating with radiation, electron beam, ultraviolet rays or the like can also be employed. Among these, the solution polymerization method using a polymerization initiator is preferable because the molecular weight can be easily adjusted and impurities can be reduced. For example, ethyl acetate, toluene, methyl ethyl ketone or the like is used as a solvent, and the polymerization initiator is preferably 0.01 to 0.50 mass with respect to 100 mass parts of the total amount of components (a-1) to (a-3). Part is added, and it is obtained by reacting at a reaction temperature of 60 to 90 ° C. for 3 to 10 hours in a nitrogen atmosphere. Examples of the polymerization initiator include azo compounds such as azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), azobiscyanovaleric acid; tert-butyl peroxypivalate, tert-butyl. Organic peroxides such as peroxybenzoate, tert-butylperoxy-2-ethylhexanoate, di-tert-butyl peroxide, cumene hydroperoxide, benzoyl peroxide, tert-butyl hydroperoxide; hydrogen peroxide And inorganic peroxides such as ammonium persulfate, potassium persulfate, and sodium persulfate. These may be used alone or in combination of two or more.

  The hydroxy group-containing (meth) acrylic polymer (A) obtained by copolymerizing the components (a-1) to (a-3) has a weight average molecular weight (Mw) of 700,000 to 2,000,000. Is preferable, and it is more preferable that it is 900,000 to 1,600,000. If the weight average molecular weight is less than 700,000, heat resistance may be insufficient. On the other hand, when the weight average molecular weight exceeds 2 million, the tack is low and the bonding property may be lowered. In addition, in this invention, the value of polystyrene conversion measured by the method as described in an Example shall be employ | adopted for a weight average molecular weight.

  In addition, the said component (A) may be used independently and may be used in combination of 2 or more type of polymer.

(B) Isocyanate-based curing agent In addition to the component (A), the pressure-sensitive adhesive composition of the present invention includes an isocyanate-based curing agent (hereinafter, also simply referred to as “component (B)”). The isocyanate curing agent reacts and bonds with the hydroxy group and the polycarbonate diol (C) in the hydroxy group-containing (meth) acrylic polymer (A) to form a crosslinked structure.

  The isocyanate curing agent used in the present invention is not particularly limited. Specifically, for example, triallyl isocyanate, dimer acid diisocyanate, 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), 4,4′- Diphenylmethane diisocyanate (4,4′-MDI), 2,4′-diphenylmethane diisocyanate (2,4′-MDI), 1,4-phenylene diisocyanate, xylylene diisocyanate (XDI), tetramethylxylidene diisocyanate (TMXDI), Aromatic diisocyanates such as tolidine diisocyanate (TODI) and 1,5-naphthalene diisocyanate (NDI); hexamethylene diisocyanate (HDI), trimethylhexamethylene diisocyanate (TMHDI), lysine diisocyanate Aliphatic diisocyanates such as norbornane diisocyanate methyl (NBDI); transcyclohexane-1,4-diisocyanate, isophorone diisocyanate (IPDI), H6-XDI (hydrogenated XDI), H12-MDI (hydrogenated MDI), etc. Alicyclic diisocyanates; carbodiimide-modified diisocyanates of the above diisocyanates; or their isocyanurate-modified diisocyanates. Moreover, the adduct body of said isocyanate compound and polyol compounds, such as a trimethylol propane, the biuret body and isocyanurate body of these isocyanate compounds can also be used conveniently.

  The isocyanate curing agent may be synthesized or a commercially available product may be used. Examples of commercially available isocyanate curing agents include Coronate L, Coronate HL, Coronate 2030, Coronate 2031 (manufactured by Nippon Polyurethane Industry Co., Ltd.), Takenate (registered trademark) D-102, Takenate (registered trademark) D- 110N, Takenate (registered trademark) D-200, Takenate (registered trademark) D-202 (manufactured by Mitsui Chemicals Polyurethane Co., Ltd.), Duranate (trademark) 24A-100, Duranate (trademark) TPA-100, Duranate (trademark) TKA-100, Duranate ™ P301-75E, Duranate ™ E402-90T, Duranate ™ E405-80T, Duranate ™ TSE-100, Duranate ™ D-101, Duranate ™ D- 201 (above, Asahi Formed Chemicals Co., Ltd.), and the like.

  Among these isocyanate curing agents, Coronate L, Coronate HL, Takenate (registered trademark) D110N, and Duranate (trademark) 24A-100 are preferable, Coronate L and Takenate (registered trademark) D110N are more preferable, and Coronate L is particularly preferable. In addition, these isocyanate type hardening | curing agents may be used independently and may be used in combination of 2 or more type.

  In this invention, it is preferable that the compounding quantity of a component (B) is 0.05-5 mass parts with respect to 100 mass parts of components (A). If it is this range, the adhesive composition of this invention may have the outstanding heat resistance and a softness | flexibility. The blending amount is more preferably 0.05 to 1.0 part by mass, and still more preferably 0.05 to 0.7 part by mass.

(C) Polycarbonate diol In addition to the component (A) and the component (B), the pressure-sensitive adhesive composition of the present invention contains a polycarbonate diol (hereinafter, also simply referred to as “component (C)”).

  The polycarbonate diol used in the present invention is not particularly limited. The polycarbonate diol is synthesized by reacting phosgene, diaryl carbonate or ethylene carbonate with a diol compound or a bisphenol compound. Examples of the diol compound include 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 3-methyl-1,5-pentanediol, 1 , 8-octanediol, 2-methyl-1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, 1,4 -C2-C12 such as cyclohexanediol, 1,3-cyclohexanediol, tricyclohexanedimethanol, pentacyclopentadecanedimethanol 1,4-butanediol, 1,6-hexanediol, 1,12-dodecanediol, etc. Alkylene diols; polyethylene glycol, polypropylene glycol , Polytetramethylene glycol, polybutylene glycol, polyhexamethylene glycol, polyheptamethylene glycol, polyether diols such as poly decamethylene glycol. Examples of bisphenol compounds include bisphenol A, bisphenol F, methylene bis (4-hydroxyphenyl), and the like. A mixture of two or more of the above diol compounds, a mixture of two or more of the above bisphenol compounds, or a mixture of a diol compound and a bisphenol compound can also be used.

  The polycarbonate diol may be synthesized or a commercially available product may be used. Examples of commercially available polycarbonate products include PCDL T6002, PCDL T6001, PCDL T5652, PCDL T5651, PCDL T5650J, PCDL T4672, PCDL T4671, PCDL T4692, PCDL T4691 (above, manufactured by Asahi Kasei Chemicals Corporation), PLACEL CD-205, PLACEL 205. , PLACEL 205HL, PLACEL 210, PLACEL 210PL, PLACEL 210HL, PLACEL 220, PLACEL 220PL, or PLACEL 220HL (manufactured by Daicel Chemical Industries, Ltd.).

  Among these polycarbonate diols, PCDL T5650J and PCDL T5651 are preferable, and PCDL T5650J is more preferable.

  The number average molecular weight of the polycarbonate diol is preferably 500 to 1500, and more preferably 700 to 1200. When the number average molecular weight is less than 500, the heat resistance may decrease. On the other hand, when it exceeds 1500, compatibility with a component (A) falls and there exists a possibility that an adhesive composition may be whitened. In addition, in this invention, the value measured by the method as described in the below-mentioned Example shall be employ | adopted for a number average molecular weight.

  In addition, the said polycarbonate diol may be used independently and may be used in combination of 2 or more type.

  In this invention, it is preferable that the compounding quantity of the said polycarbonate diol (C) is 0.1-5 mass parts with respect to 100 mass parts of component (A). If it is this range, the adhesive composition of this invention may have the outstanding heat resistance and a softness | flexibility. The blending amount is more preferably 0.2 to 4 parts by mass, and still more preferably 0.3 to 3 parts by mass.

  Moreover, in addition to the said component (A)-(C), the adhesive composition of this invention may also contain a silane coupling agent. By using a silane coupling agent, the reactivity can be improved and the mechanical strength and adhesive strength of the cured product can be improved. Such a silane coupling agent is not particularly limited. Specifically, for example, methyltrimethoxysilane, dimethyldimethoxysilane, trimethylmethoxysilane, n-propyltrimethoxysilane, ethyltrimethoxysilane, diethyldiethoxysilane, n-butyltrimethoxysilane, n-hexyltriethoxysilane , N-octyltrimethoxysilane, phenyltrimethoxysilane, diphenyldimethoxysilane, cyclohexylmethyldimethoxysilane, vinyltrichlorosilane, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, β- (3 4-epoxycyclohexyl) ethyltrimethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-methacryloxypropylme Tildimethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropylmethyldiethoxysilane, γ-methacryloxypropyltriethoxysilane, γ-acryloxypropyltrimethoxysilane, N-β- (aminoethyl)- γ-aminopropylmethyldimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltrimethoxysilane, N-β- (aminoethyl) -γ-aminopropyltriethoxysilane, γ-aminopropyltrimethoxysilane, γ-aminopropyltriethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, γ-mercaptopropyltrimethoxysilane, γ-mercaptopropylmethyldimethoxysilane, bis- (3- [ bird Tokishishiriru] propyl) tetrasulfide, .gamma. isocyanatepropyltriethoxysilane and the like. Further, a silane coupling agent having a functional group such as an epoxy group (glycidoxy group), an amino group, a mercapto group, or a (meth) acryloyl group, and a functional group having reactivity with these functional groups. A compound having a hydrolyzable silyl group obtained by reacting an agent, another coupling agent, polyisocyanate and the like with each functional group in an arbitrary ratio can also be used.

  The silane coupling agent may be synthesized or a commercially available product may be used. Examples of commercially available silane coupling agents include KBM-303, KBM-403, KBE-402, KBM-403, KBE-502, KBE-503, KBM-5103, KBM-573, KBM-802, and KBM-. 803, KBE-846, KBE-9007 (manufactured by Shin-Etsu Chemical Co., Ltd.) and the like.

  Among these silane coupling agents, KBM-303, KBM-403, KBE-402, KBM-403, KBM-5103, KBM-573, KBM-802, KBM-803, KBE-846, and KBE-9007 are preferable. KBM-403 is more preferred. In addition, the said silane coupling agent may be used independently and may be used in combination of 2 or more types.

  In the present invention, the amount of the silane coupling agent used is not particularly limited. Specifically, the compounding amount of the silane coupling agent is preferably 0.01 to 5 parts by mass, more preferably 0.03 with respect to 100 parts by mass of the total amount of components (A) to (C). It is -2.0 mass parts, More preferably, it is 0.05-0.5 mass part. If it exists in this range, the outstanding heat resistance and adhesiveness can be exhibited. When the compounding amount of the silane coupling agent is less than 0.01 parts by mass, the glass adhesiveness may be lowered. On the other hand, when it exceeds 5.0 mass parts, heat resistance may fall.

  In addition to or in place of the silane coupling agent, the pressure-sensitive adhesive composition of the present invention comprises an ionic liquid, an inorganic filler, a softener, an antioxidant, an anti-aging agent, a stabilizer, and an adhesive. Giving resin, modifying resin (polyol resin, phenol resin, acrylic resin, polyester resin, polyolefin resin, epoxy resin, epoxidized polybutadiene resin, etc.), leveling agent, antifoaming agent, plasticizer, dye, pigment (color pigment, constitution) Pigments, etc.), treatment agents, UV blockers, fluorescent brighteners, dispersants, heat stabilizers, light stabilizers, UV absorbers, antistatic agents, lubricants and solvents. Examples of the ionic liquid include phosphonium ion, pyridinium ion, pyrrolidinium ion, imidazolium ion, guanidinium ion, ammonium ion, isouronium ion, thiouronium ion, piperidinium ion, pyrazolium ion, sulfonium ion, and the like. As cation component and anion component, halogen ion, nitrate ion, sulfate ion, phosphate ion, perchlorate ion, thiocyanate ion, thiosulfate ion, sulfite ion, tetrafluoroborate ion, hexafluorophosphate ion, formate ion, And substances having an anion component such as oxalate ion, acetate ion, trifluoroacetate ion, and alkylsulfonate ion. Examples of the antioxidant include dibutylhydroxytoluene (BHT), Irganox (registered trademark) 1010, Irganox (registered trademark) 1035FF, Irganox (registered trademark) 565 (all manufactured by Ciba Specialty Chemicals) and the like. Can be mentioned. Examples of the tackifying resin include rosins such as rosin acid, polymerized rosin acid and rosin acid ester, terpene resin, terpene phenol resin, aromatic hydrocarbon resin, aliphatic saturated hydrocarbon resin and petroleum resin. Although the usage-amount of an additive in the case of using the said additive is not restrict | limited in particular, For example, it is 0.1-20 mass parts with respect to 100 mass parts of total amounts of the said component (A)-(C). is there.

  The pressure-sensitive adhesive composition of the present invention can be prepared by mixing the above-described components all together, mixing each component sequentially, or mixing any plural components and then mixing the remaining components. It can manufacture by stirring so that it may become a uniform mixture. More specifically, it can be prepared by heating, for example, to a temperature of 30 to 40 ° C. as necessary, and stirring for 10 minutes to 5 hours until it becomes uniform with a stirrer or the like.

  The pressure-sensitive adhesive composition of the present invention can be used for bonding various substrates. Examples of the substrate that can be used here include glass, plastic film, paper, and metal foil. Examples of the glass include general inorganic glass. Examples of the plastic in the plastic film include polyvinyl chloride resin, polyvinylidene chloride, cellulose resin, acrylic resin, cycloolefin resin, amorphous polyolefin resin, polyethylene, polypropylene, polystyrene, ABS resin, polyamide, and polyester. , Polycarbonate, polyurethane, polyvinyl alcohol, ethylene-vinyl acetate copolymer and chlorinated polypropylene. The amorphous polyolefin-based resin usually has a polymerization unit of a cyclic polyolefin such as norbornene or a polycyclic norbornene-based monomer, and may be a copolymer of a cyclic olefin and a chain cyclic olefin. Commercially available non-crystalline polyolefin resins such as Arton from JSR Corporation, ZEONEX (registered trademark) from ZEON Corporation, ZEONOR (registered trademark), APO from Mitsui Chemicals, Apel (registered trademark), etc. There is. In order to form an amorphous polyolefin-based resin into a film, a known method such as a solvent casting method or a melt extrusion method is appropriately used. Examples of the paper include imitation paper, fine paper, craft paper, art coat paper, caster coat paper, pure white roll paper, parchment paper, water resistant paper, glassine paper, and corrugated paper. Examples of the metal foil include aluminum foil.

  Therefore, this invention also provides an optical member provided with the adhesive layer formed from the adhesive composition of this invention.

  Preferred examples of the optical member include a polarizing plate, a retardation plate, an optical film for plasma display, and a conductive film for touch panel. Among these, the adhesive composition of this invention is excellent in the adhesiveness of a polarizing plate and glass. Of course, the present invention is not limited to the above-described form, and can be used for bonding other members.

  The pressure-sensitive adhesive composition of the present invention may be used by directly applying to one or both sides of an optical film to form a pressure-sensitive adhesive layer, or by previously forming a pressure-sensitive adhesive layer on a release film. It may be used by transferring to one side or both sides.

  Coating of the pressure-sensitive adhesive composition of the present invention may be performed by a conventionally known method, for example, natural coater, knife belt coater, floating knife, knife over roll, knife on blanket, spray, dip, kiss roll, squeeze roll, Various coating methods using apparatuses such as a reverse roll, an air blade, a curtain flow coater, a doctor blade, a wire bar, a die coater, a comma coater, a baker applicator, and a gravure coater may be mentioned. Moreover, what is necessary is just to select the application | coating thickness (thickness after drying) of the composition of this invention according to the base material to be used and a use, Preferably it is 5-30 micrometers, More preferably, it is 15-25 micrometers. is there.

  The viscosity of the pressure-sensitive adhesive composition of the present invention is not particularly limited. However, considering the ease of coating and the like, the viscosity at 25 ° C. is preferably 0.5 to 5.0 Pa · s, more preferably 1.0 to 3.0 Pa · s. If the viscosity is less than 0.5 Pa · s, there may be a case where the coating surface is crushed. On the other hand, if it exceeds 5.0 Pa · s, coating streaks may occur.

  The pressure-sensitive adhesive layer obtained from the pressure-sensitive adhesive composition of the present invention is obtained by crosslinking the pressure-sensitive adhesive composition as described above. At that time, the pressure-sensitive adhesive composition is generally crosslinked after application of the pressure-sensitive adhesive composition, but it is also possible to transfer a pressure-sensitive adhesive layer comprising the pressure-sensitive adhesive composition after crosslinking to a substrate or the like. is there. Crosslinking of this pressure-sensitive adhesive composition is usually carried out by allowing it to stand under conditions of a temperature of 20 to 40 ° C., a relative humidity of 30 to 70% RH, and normal pressure (atmospheric pressure).

  The pressure-sensitive adhesive composition of the present invention exhibits excellent flexibility, thereby exhibiting excellent reworkability (removability) and processability. For example, even if a positional deviation between the optical film and the adherend occurs in the bonding step of the optical member, the optical film can be peeled without any adhesive remaining on the adherend. In particular, when used for a polarizing plate, excellent light leakage resistance and reworkability can be obtained.

  In addition, since the pressure-sensitive adhesive composition of the present invention has excellent heat resistance, it can exhibit high durability that does not float or peel off by heat treatment or high-humidity treatment.

  The effects of the present invention will be described using the following examples and comparative examples. However, the technical scope of the present invention is not limited only to the following examples.

  The solid content and viscosity of the solution in which the pressure-sensitive adhesive composition is dissolved, and the weight average molecular weight of the hydroxy group-containing acrylic polymer (A) and the number average molecular weight of the polycarbonate diol (C) are measured by the following methods. went.

<Solid content>
About 1 g of the polymer solution is precisely weighed in a precisely weighed glass dish. After drying at 105 ° C. for 1 hour, the temperature is returned to room temperature, and the total mass of the glass dish and the remaining solid is precisely weighed. The solid content was calculated by the following formula 1, where X is the mass of the glass plate, Y is the total mass of the glass plate before drying and the polymer solution, and Z is the total mass Z of the glass plate and the remaining solid content.

<Viscosity>
The pressure-sensitive adhesive solution contained in the glass bottle was temperature-controlled at 25 ° C. and measured with a B-type viscometer.

<Weight average molecular weight and number average molecular weight>
The measurement was performed according to the measurement method and measurement conditions shown in Table 1 below.

Example 1
In a container equipped with a reflux and a stirrer, 98 parts by mass of n-butyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), 1 part by weight of 2-hydroxyethyl acrylate (manufactured by Nippon Shokubai Co., Ltd.), acrylic acid (manufactured by Nippon Shokubai Co., Ltd.) 1 part by mass and 130 parts by mass of ethyl acetate were added. Next, the mixture was heated to 65 ° C. while performing nitrogen substitution, 0.075 parts by mass of azobisisobutyronitrile (AIBN) was added, and polymerization was performed for 6 hours while maintaining 65 ° C. After completion of the polymerization reaction, 270 parts by mass of ethyl acetate was added for dilution to obtain a hydroxy group-containing acrylic polymer (A) solution. The obtained polymer solution had a solid content of 19.0% by mass and a viscosity of 4.0 Pa · s. Moreover, the weight average molecular weight of the obtained hydroxy group-containing acrylic polymer (A) was 1,200,000.

  Next, 0.2 parts by mass of the polymer solution obtained above and coronate L (trimethylolpropane / tolylene diisocyanate trimer adduct, manufactured by Nippon Polyurethane Industry Co., Ltd.), which is an isocyanate curing agent (B), PCDL T5650J which is polycarbonate diol (C) (diol component: 1,6-hexanediol and 1,5-pentanediol, manufactured by Asahi Kasei Chemicals Corporation, number average molecular weight: 800) 0.5 part by mass, and silane coupling agent KBM-403 (manufactured by Shin-Etsu Chemical Co., Ltd.) 0.1 parts by mass was mixed at 25 ° C. for 15 minutes to obtain a solution in which the pressure-sensitive adhesive composition was dissolved.

  This solution is applied onto a peeled PET film (Mitsubishi Chemical Polyester Film Co., Ltd., MRF38, thickness: 38 μm) using a baker applicator so that the thickness after drying is 25 μm, and bonded to a polarizing plate. did. Thereafter, the sample was aged for 7 days under conditions of 23 ° C./45% RH to obtain a sample for evaluation.

(Examples 2-7, Comparative Examples 1-3)
Preparation of a solution in which the pressure-sensitive adhesive composition is dissolved in the same manner as in Example 1 except that the monomer, isocyanate, polycarbonate diol, and silane coupling agent were used at the composition ratio shown in Table 2 below. And the sample for evaluation was produced.

  The samples for evaluation of Examples 1 to 7 and Comparative Examples 1 to 3 obtained as described above were evaluated for heat resistance, wet heat resistance, light leakage resistance, adhesive strength, and reworkability according to the following methods.

<Heat resistance test>
A sample cut to a size of 120 mm (polarizing plate MD direction) × 60 mm was bonded to a glass plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Then, it put into 80 degreeC environment and observed the external appearance after 120 hours. In Table 1 below, “good” means that the glass plate and the polarizing plate did not peel off, and the appearance was good, and “peeling” means that the glass plate and the polarizing plate peeled off. And “foaming” mean that bubbles were generated in the pressure-sensitive adhesive layer, respectively.

<Moisture and heat resistance test>
A sample cut to a size of 120 mm (polarizing plate MD direction) × 60 mm was bonded to a glass plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Then, it put into 60 degreeC / 90% RH environment, and the external appearance after 120 hours was observed. In Table 1 below, “good” means that the glass plate and the polarizing plate did not peel off, and the appearance was good, and “peeling” means that the glass plate and the polarizing plate peeled off. Means each.

<Light leakage resistance test>
A sample cut into a size of 120 mm (polarizing plate MD direction) × 60 mm and a sample cut into a size of 120 mm (polarizing plate TD direction) × 60 mm were bonded so as to overlap each surface of the glass plate, Autoclaving was performed for 20 minutes at 50 ° C. and 0.49 MPa (5 kg / cm ² ). Then, it put into 80 degreeC environment and observed the external appearance after 120 hours. In Table 1 below, “good” means that almost no light leakage occurs, “bad” means that the end of the polarizing plate is whitened, and “unevaluable” means that the glass plate and the polarizing plate It was not possible to evaluate because peeling occurred with "spot missing" that the phenomenon that light leaks in a spot (like dot missing) occurred due to foaming, Each means.

<Adhesive strength and reworkability>
The sample cut to a width of 25 mm was bonded to a glass plate, and autoclaved for 20 minutes under the conditions of 50 ° C. and 0.49 MPa (5 kg / cm ² ). Thereafter, using a tensile tester, the adhesive strength was measured and the peeled state was observed at a peeling angle of 90 degrees and a peeling speed of 0.3 m / min (measuring environment: 20 ° C./50% RH). In Table 1 below, “af” indicates interfacial fracture, and “transfer” indicates that the film was peeled off between the pressure-sensitive adhesive and the polarizing plate and remained on the pressure-sensitive adhesive layer glass plate.

  The evaluation results of each test are shown in Table 2 below.

  As can be seen from Table 2 above, the optical members (Examples 1 to 7) using the pressure-sensitive adhesive composition of the present invention are comparative examples 1 and 2 in which the content of the polycarbonate diol is outside the scope of the present invention, and hydroxy. It turns out that it is excellent in heat resistance, heat-and-moisture resistance, light leakage resistance, and reworkability compared with the optical member using the adhesive composition of the comparative example 3 using the acrylic polymer which does not have a group.

It is a schematic diagram which shows the crosslinked structure of the conventional adhesive composition. It is a schematic diagram which shows the crosslinked structure of the adhesive composition of this invention.

Explanation of symbols

1 Acrylic resin,
2, B isocyanate curing agent,
3 polyols,
A hydroxy group-containing (meth) acrylic polymer,
C Polycarbonate diol.

Claims (3)

(A-1) 99.5-80 parts by mass of a (meth) acrylate monomer, (a-2) 0.5-10 parts by mass of a hydroxy group-containing (meth) acrylic monomer, and (a-3) the above (a -1) and other monomers copolymerizable with (a-2) 0 to 10 parts by mass (however, the total amount of (a-1) to (a-3) is 100 parts by mass) Hydroxy group-containing (meth) acrylic polymer (A),
An isocyanate curing agent (B);
Polycarbonate diol (C);
Only including,
The amount of the isocyanate curing agent (B) is 0.05 to 5 parts by mass with respect to 100 parts by mass of the hydroxy group-containing (meth) acrylic polymer (A),
The compounding quantity of the said polycarbonate diol (C) is an adhesive composition which is 0.1-5 mass parts with respect to 100 mass parts of said hydroxy group containing (meth) acrylic-type polymers (A) .   The pressure-sensitive adhesive composition according to claim 1, further comprising a silane coupling agent. An optical member provided with the adhesive layer formed from the adhesive composition of Claim 1 or 2 .

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