KR20140029415A - Polarizing plate and laminated optical member - Google Patents

Abstract

A polarizing plate composed of a polyvinyl alcohol polarizer and a protective film bonded to the polarizer via an adhesive, the adhesive comprising 100 parts by weight of the photocationic curable component (A) and the photocationic polymerization initiator (B). It contains-10 weight part, and the hardened | cured material is formed from the photocurable adhesive composition which shows the storage elastic modulus more than 1000 Mpa at 80 degreeC, and said photocationic curable component (A) is the following (A1) and (A2) It is prepared to contain the following amount based on the total amount. 50-95 weight% of alicyclic epoxy compounds (A1) which have an epoxy group couple | bonded with an alicyclic ring, and chlorine content are 1 weight% or less, and diglycidyl represented by following formula (I) (Z is an alkylene group etc.) 5-50 weight% of compound (A2).

Description

POLARIZING PLATE AND LAMINATED OPTICAL MEMBER}

This invention relates to the polarizing plate which bonded together the protective film on the single side | surface or both surfaces of a polarizer using specific photocurable adhesive agent. This invention also relates to the laminated optical member which laminated | stacked other optical layers, such as retardation film, on this polarizing plate.

The polarizing plate is useful as one of the optical components constituting the liquid crystal display device. A polarizing plate is normally used by being attached to a liquid crystal display device in the state which laminated | stacked the protective film on both surfaces of the polarizer. It is also known to form a protective film only on one side of the polarizer, but in many cases, a layer having another optical function is bonded to the other one surface as a protective film instead of a simple protective film. Moreover, as a manufacturing method of a polarizer, the method of carrying out boric acid treatment of the uniaxially-stretched polyvinyl alcohol resin film dyed with the dichroic dye, and washing with water, and drying is widely known.

Usually, a protective film is bonded immediately to the polarizer immediately after the above-mentioned water washing and drying. This is because the polarizer after drying has a weak physical strength, and once this is wound, it is torn in the processing direction. Therefore, the polarizer after drying is conventionally apply | coats a water-based adhesive immediately, and then a protective film is bonded together simultaneously through this adhesive agent. Conventionally, the triacetyl cellulose film of thickness 30-120 micrometers is used as a protective film.

The triacetyl cellulose has high moisture permeability, and the polarizing plate bonded to this as a protective film has a problem such as deterioration under moist heat, for example, under conditions such as a temperature of 70 ° C. and a relative humidity of 90%. Therefore, it is also known to use amorphous polyolefin resin which has lower moisture permeability than triacetyl cellulose, for example, norbornene-type resin as a protective film.

When bonding the protective film which consists of resin with low moisture permeability to a polyvinyl alcohol-type polarizer, adhesive strength is high in the aqueous solution of the polyvinyl alcohol-type resin generally used as an adhesive agent for bonding a polyvinyl alcohol-type polarizer and triacetyl cellulose conventionally. There was a problem that it was not sufficient or the appearance of the polarizing plate obtained would be poor. This is because the resin film with low water vapor transmission rate is generally hydrophobic, or the water cannot be sufficiently dried as a solvent because of low water vapor transmission rate. On the other hand, it is also known to bond different types of protective films on both surfaces of the polarizer. For example, a protective film made of a resin having low moisture permeability such as amorphous polyolefin resin is bonded to one surface of the polarizer, and the other side of the polarizer is bonded. There is also a proposal to bond a protective film made of a resin having high moisture permeability, such as cellulose resins including triacetyl cellulose, to cotton.

Therefore, as an adhesive agent that provides high adhesion between a protective film made of a resin having a low moisture permeability and a polyvinyl alcohol polarizer, and also provides a high adhesion force between a high moisture-permeable resin such as a cellulose resin and a polyvinyl alcohol polarizer, Attempts have been made to use active energy ray curable adhesives. For example, Japanese Unexamined Patent Application Publication No. 2004-245925 (Patent Document 1) discloses an adhesive mainly composed of an epoxy compound containing no aromatic ring, and the adhesive is prepared by cationic polymerization by irradiation of active energy rays. Curing and sticking a polarizer and a protective film are proposed. In addition, JP 2008-257199 A (Patent Document 2) combines an alicyclic epoxy compound and an epoxy compound having no alicyclic epoxy group, and combines a photocurable adhesive compound with a photocationic polymerization initiator to form a polarizer and a protective film. The technique used for the adhesion of the is disclosed.

In addition, although Unexamined-Japanese-Patent No. 2009-181046 (patent document 3) and Unexamined-Japanese-Patent No. 2002-365432 (patent document 4) are a case where water-based adhesive agents are used, the wettability of the protective film and adhesive agent at the time of polarizing plate manufacture According to the viscosity of the adhesive, it is described that appearance defects occur in the polarizing plate after production, and these parameters have a great influence on productivity, and as a countermeasure, improvement of wettability and low viscosity of the adhesive itself are effective. In particular, it is described that the contribution of viscosity is large.

Unlike the solvent type adhesive agent, the epoxy type photocurable adhesive agent as shown in patent documents 1 and 2 is normally prepared without mix | blending a solvent substantially. Therefore, in many cases, it is necessary to increase the ratio of the low viscosity component in a composition in order to lower a viscosity. Reducing the viscosity of the adhesive liquid before curing by such a change of composition ratio causes a considerable lack of hardness of the adhesive bond layer after hardening, and there exists a concern that the polarizing plate after adhesion will become difficult to show sufficient durability. Therefore, improvement of the wettability by surface modification of a film, addition of a leveling agent, etc. was mainly employ | adopted until now as a countermeasure to avoid the external appearance defect in the manufacturing process of a polarizing plate.

Japanese Unexamined Patent Publication No. 2004-245925 Japanese Unexamined Patent Publication No. 2008-257199 Japanese Unexamined Patent Publication No. 2009-181046 Japanese Patent Application Laid-Open No. 2002-365432

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in order to improve the problem that when bonding an polarizer and a protective film using an epoxy-type photocurable adhesive agent, when the adhesive agent before hardening lowers viscosity, an adhesive layer after hardening does not show sufficient hardness, and this invention is used. Came to complete. Therefore, the subject of this invention is a polarizing plate in which a polarizer and a protective film were bonded together using the epoxy-type photocurable adhesive agent, after lowering the viscosity of the photocurable adhesive agent used there, improving application | coating aptitude, and after the adhesive agent hardens, A sufficient hardness is provided and the polarizing plate in which the adhesive force of a polarizer and a protective film became high is provided. Another object of this invention is to laminate | stack another optical layer, such as retardation film, on this polarizing plate, and to provide the laminated optical member used suitably for a liquid crystal display device.

As a result of the study, at least two types of photocationic curable epoxy compounds such as alicyclic epoxy compounds and diglycidyl compounds were combined to reduce the amount of chlorine in the diglycidyl compound in the photocurable adhesive substantially free of solvent. It was found that low viscosity by adjustment of the composition ratio is possible while maintaining the hardness of the adhesive layer after curing at a high value. The present invention includes the following.

[1] A polarizing plate comprising a polarizer made of a polyvinyl alcohol-based resin film in which a dichroic dye is adsorbed and oriented, and a protective film made of a transparent resin bonded to at least one surface of the polarizer via an adhesive, the adhesive The photocurable adhesive agent contains 100 weight part of photocationic curable components (A), and 1-10 weight part of photocationic polymerization initiators (B), and the hardened | cured material shows a storage elastic modulus of 1000 Mpa or more in 80 degreeC. A polarizing plate formed of a composition, wherein the photocationic curable component (A) is prepared so as to contain the following amounts (A1) and (A2), based on the total amount thereof.

50 to 95% by weight of an alicyclic epoxy compound (A1) having two or more epoxy groups in the molecule, at least one of which is bonded to an alicyclic ring, and

5-50 weight% of the diglycidyl compound (A2) represented by following formula (I) as chlorine content is 1 weight% or less:

[Chemical Formula 1]

In the formula, Z is an alkylene group having 1 to 9 carbon atoms, an alkylidene group having 3 or 4 carbon atoms, a divalent alicyclic hydrocarbon group, or a divalent group represented by the formula -C _m H _2m -Z ¹ -C _n H _2n-. Here, -Z ¹ -represents -SO _2- , -SO- or -CO-, and m and n each independently represent an integer of 1 or more, but the sum of both is 9 or less.

[2] The polarizing plate according to [1], wherein the protective film bonded to at least one surface of the polarizer is made of an acetyl cellulose resin.

[3] The protective film bonded to at least one side of the polarizer is made of transparent resin selected from the group consisting of amorphous polyolefin resins, polyester resins, polycarbonate resins, and chain polyolefin resins. Polarizer.

[4] A protective film made of acetyl cellulose resin is bonded to one surface of the polarizer via the adhesive, and an amorphous polyolefin resin, polyester resin, polycarbonate resin, and chain to the other surface of the polarizer. The polarizing plate as described in [1] in which the protective film which is a film which consists of transparent resin chosen from the group which consists of a type | mold polyolefin resin is bonded through the said adhesive agent.

[5] A laminated optical member comprising a laminate of the polarizing plate according to any one of [1] to [4] and another optical layer.

[6] The laminated optical member according to [5], wherein the optical layer contains a retardation film.

As for the polarizing plate of this invention, the photocurable adhesive agent used for the manufacture shows a low viscosity before hardening, and coating application property is improved, but shows a high storage elastic modulus after hardening, and the polarizer and a protective film adhere | attach favorably. Even if this polarizing plate is subjected to the cold shock test (heat shock test) which repeats what is placed in a high temperature environment and a low temperature environment, for example, there is little possibility that a polarizer will generate | occur | produce a crack and will be excellent in reliability. Moreover, the laminated optical member in which other optical layers, such as a retardation film, were laminated | stacked on this polarizing plate also has a small possibility of generating a crack in a polarizer even under severe conditions, and the liquid crystal display device to which it was applied also becomes excellent in reliability.

Hereinafter, embodiments of the present invention will be described in detail. In this invention, the protective film which consists of transparent resin is bonded together on at least one surface of the polarizer which consists of a polyvinyl alcohol-type resin film by which a dichroic dye was adsorbed-oriented through a photocurable adhesive agent, and is used as a polarizing plate. And this photocurable adhesive agent contains 100 weight part of photocationic curable components (A), and 1-10 weight part of photocationic polymerization initiators (B), and the hardened | cured material has a storage elastic modulus of 1000 Mpa or more in 80 degreeC. It forms with the photocurable adhesive composition which shows. Furthermore, another optical layer is laminated | stacked on this polarizing plate, and it is set as the laminated optical member used suitably for a liquid crystal display device. Then, description advances in order of the photocurable adhesive composition used for manufacture of a polarizing plate, the polarizing plate using the same, and the laminated optical member using the same.

[Photocurable Adhesive Composition]

As mentioned above, the photocurable adhesive composition used for this invention contains 100 weight part of photocationic curable components (A), and 1-10 weight part of photocationic polymerization initiators (B), and is further The photocationic curable component (A) contains the following (A1) and (A2) in the following amounts based on the total amount thereof.

50-95 weight% of alicyclic epoxy compounds (A1) which have two or more epoxy groups in a molecule, and at least 1 of them is couple | bonded with the alicyclic ring, and

5 to 50 weight% of the diglycidyl ether compound (A2) represented by said Formula (I) as chlorine content is 1% or less.

(Photocationic curable component)

Although the alicyclic epoxy compound (A1) which becomes a main component of a photocationic curable component (A) may be a well-known general epoxy compound, it does not contain an aromatic ring in the molecular structure from a viewpoint of weather resistance, refractive index, and photocurability. desirable. As an alicyclic epoxy compound (A1), what is represented by the following general formula (1)-(23) is mentioned, for example.

(2)

(3)

[Chemical Formula 4]

In each said general formula, R <^1> -R <^46> represents a hydrogen atom or a C1-C6 alkyl group each independently. If the R ¹ - R ⁴⁶ is an alkyl group, where the bond to an alicyclic structure is an arbitrary position of the first position or 6 position. The alkyl group having 1 to 6 carbon atoms may be linear, branched, or may have an alicyclic structure. Y <^1> represents an oxygen atom or an alkanediyl group, Y <^2> -Y <^21> may respectively independently be a linear, may have a branch, and represents the alkanediyl group which may have an alicyclic structure. The carbon number of the alkanediyl group is 1-20 in Y ² , Y ⁴ , Y ⁹ , Y ¹⁰ , Y ¹¹ , Y ¹² , Y ¹³ , Y ¹⁴ , Y ¹⁵ , Y ¹⁸ , Y ¹⁹ , Y ²⁰ , and Y ²¹ . , Y ¹ , Y ³ , Y ⁵ , Y ⁶ , Y ⁷ , Y ⁸ , Y ¹⁶ , and Y ¹⁷ are 2 to 20. Z ¹ to Z ² each independently represent alkanetriyl group which may be linear, may have a branch, or may have an alicyclic structure. Z ¹ is 2-20, and Z ² is 1-20 in carbon number of an alkane triyl group. T <^1> may be linear, may have a branch, and represents the C1-C20 alkane tetrayl group which may have an alicyclic structure. a-r represents the integer of 0-20.

Said alicyclic epoxy compound (A1) can be used individually by 1 type or in mixture of 2 or more types.

The diglycidyl compound (A2) which becomes another component of a photocationic curable component (A) is represented by said Formula (I). In Formula (I), Z is a C1-C9 alkylene group, a C3-C4 alkylidene group, a bivalent alicyclic hydrocarbon group, or a formula:

-C _m H _2m -Z ¹ -C _n H _2n-

As a divalent group shown, in which -Z ¹ - is -SO ₂ -, and -SO- or -CO-, m and n are each independently an integer of 1 or more, but, the total of both is 9 or less. Typical examples of the divalent alicyclic hydrocarbon group include cyclopentylene and cyclohexylene.

In Formula (I), the compound whose Z is an alkylene group is the diglycidyl ether of alkylene glycol. Specific examples thereof include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, 1,3-propanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, 1,6-hexane Diol diglycidyl ether, neopentyl glycol diglycidyl ether, 3-methyl-1,5-pentanediol diglycidyl ether, 2-methyl-1,8-octanediol diglycidyl ether, 1, 4-cyclohexanedimethanol and the like.

In the formula (I), Z is a divalent group represented by the formula -C _m H _2m -Z ¹ -C _n H _2n- , wherein Z is an alkylene group having 2 or more carbon atoms, and the CC bond of the alkylene group is- and it corresponds to what is interrupted by, -SO-, or -CO- - SO _2.

The diglycidyl compound represented by Formula (I) is generally distributed in the state containing a lot of chlorine for the reason of a manufacturing process. That is, in the preparation of this compound, epichlorohydrin in the presence of an acidic catalyst such as sulfuric acid, boron trifluoride, tin tetrachloride and the like in the dihydric alcohol corresponding to the formula HO-Z-OH including the alkylene glycols In the case of using a two-stage method in which chlorhydrin ether is intramolecularly closed by chlorhydrin ether after the reaction, 2 mole addition of epichlorhydrin is added in the reaction of epichlorohydrin in the first step. Since the formation of a sieve is not avoided, the organic chlorine contained in this two-mole adduct is not decomposed by the intramolecular ring-closure reaction in the second step, and in general, glycidyl ethers cannot be distilled and purified. The obtained glycidyl ethers contain about 1 to 3% by weight of organic chlorine compounds as chlorine powder.

The diglycidyl compound (A2) used for this invention needs to have the chlorine content of 1% or less, for example, (1) dihydric alcohol and epichlorohydrin, in presence of an alkali metal hydroxide. The water in the reaction system is azeotropic solvent (for example, hydrocarbons such as n-hexane, cyclohexane, n-heptane, benzene, or toluene, ethers such as ethyl ether or isopropyl ether, and 1,2-dichloroethane). , Halogenated hydrocarbons such as 1,2-dichloropropane, trichloroethylene, or chloroform, and a sulfoxide compound such as a solvent having an azeotropic temperature of 30 to 90 ° C.) and reacting with azeotropic removal, (2) alkali metal hydroxide Is adjusted to 0.5 to 1.5, reacted in the presence of epichlorohydrin, treated with water washing and / or an alkali adsorbent, and then distilled off epichlorohydrin, under (3). By a de-hydroxyl compound and the epitaxial chlor high gave the like is condensed in the presence of an alkali, a method of reacting while applying ultrasonic waves, and to reduce the chlorine content.

(Photocationic polymerization initiator)

The photocationic polymerization initiator (B) compounded in the photocurable adhesive composition is a compound capable of releasing a substance for initiating cationic polymerization by light irradiation, and particularly preferably an onium salt that releases Lewis acid by light irradiation. Double salts or derivatives thereof. Typical examples of such compounds include salts of cations and anions represented by the general formula and [A] ^{y +} [B] ^{y −} .

Wherein the cation A ^{+ y} is preferably an onium, and its structure may be, for example, it can be represented by _{^{[(R 41) x Q]}} y +.

In addition, R <^45> is C1-C60 and is an organic group which may contain several atoms other than carbon, and x is an integer of 1-5. x R ^{45 's} may be each independently the same or different. Moreover, it is preferable that at least 1 is an aromatic group. Q is an atom or group of atoms selected from the group consisting of S, N, Se, Te, P, As, Sb, Bi, O, I, Br, Cl, F, N = N. Moreover, when the valence of Q in cation A ^{y +} is set to z, it is necessary to establish the relationship of y = x-z.

The anion B ^{y -} is preferably a halide complex, the structure is, for example, [LX _s] can be expressed by the ^y-.

Where L is a metal or metalloid (Metalloid) that is the central atom of the halide complex, and B, P, As, Sb, Fe, Sn, Bi, Al, Ca, In, Ti, Zn, Sc, V, Cr, Mn, Co and the like. X is halogen. s is an integer of 3-7. Moreover, when the valence of L in the anion B ^{y -} is set to t, it is necessary to establish a relationship of y = s-t.

Specific examples of the anion [LX _s ] ^y- in the general formula include tetrafluoroborate (BF ₄ ) ^- , hexafluorophosphate (PF ₆ ) ^- , and hexafluoroantimonate (SbF ₆ ) ^- and the like ^-, hexachloro antimonate (SbC1 ₆₎ ^-, are Senate (AsF ₆₎ hexafluoropropane.

The anion B ^{y -} can be preferably used also in the structure represented by ^{_{[LX s -1 (OH)]}} y-. L, X, and s are the same as above. In addition, other anions that can be used include perchlorate ions (ClO ₄ ) ^- , trifluoromethylsulfite ions (CF ₃ SO ₃ ) ^- , fluorosulfonic acid ions (FSO ₃ ) ^- , toluenesulfone acid anions and trinitrobenzene. Sulfonic acid anions; and the like.

The anion B ^{y -} can also be preferably used as, tetrakis (pentafluorophenyl) borate.

In this invention, it is especially effective to use an aromatic onium salt among such onium salts. Especially, the aromatic halonium salt of Unexamined-Japanese-Patent No. 50-151997, Unexamined-Japanese-Patent No. 50-158680, Unexamined-Japanese-Patent No. 50-151997, 52-30899, Unexamined-Japanese-Patent Group VIA aromatic onium salts described in Japanese Patent Application Laid-Open No. 56-55420, Japanese Patent Application Laid-Open No. 55-125105, etc., Group VA aromatic onium salts described in Japanese Patent Application Laid-open No. 50-158698, and Japanese Laid-Open Patent Publication No. 56-8428 Oxosulfonium salts described in Japanese Patent Application Laid-open No. 56-149402, Japanese Patent Laid-Open No. 57-192429, and the aromatic diazonium salt described in Japanese Patent Application Laid-open No. 49-17040, US Patent No. 4139655 The thiopyryllium salt described in the above is preferable.

Among these aromatic onium salts, particularly preferable ones are mentioned below.

Compounds having sulfonium cations of the following structure

[Chemical Formula 5]

In formula, R <^46> -R <^59> may be same or different, respectively, The hydrogen atom, halogen atom, or the hydrocarbon group which may contain the oxygen atom or the halogen atom, or the alkoxy group which may have a substituent, Ar is one or more hydrogen atoms It is a phenyl group which may be substituted.

Compounds with onium cations such as:

(Tolyl cumyl) iodonium, bis (tertiary butylphenyl) iodonium, triphenylsulfonium, and the like.

Specific compound names include, for example, 4- (4-benzoyl-phenylthio) phenyl-di- (4-fluorophenyl) sulfonium hexafluorophosphate, 4,4'-bis [bis ((β- Hydroxyethoxy) phenyl) sulfonio] phenylsulfide-bis-hexafluorophosphate, 4,4'-bis [bis ((β-hydroxyethoxy) phenyl) sulfonio] phenylsulfide-bis -Hexafluoroantimonate, 4,4'-bis (difluorophenylsulfonio) phenylsulfide-bis-hexafluorophosphate, 4,4'-bis (difluorophenylsulfonio) phenyl Sulfide-bis-hexafluoroantimonate, 4,4'-bis (phenylsulfonio) phenylsulfide-bis-hexafluorophosphate, 4,4'-bis (phenylsulfonio) phenylsulfide -Bis-hexafluoroantimonate, 4- (4-benzoylphenylthio) phenyl-di- (4- (β-hydroxyethoxy) phenyl) sulfonium hexafluorophosphate, 4- (4-benzoylphenyl Thio) phenyl-di- (4- (β-hydroxy) Sithoxy) phenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenyl-di- (4-fluorophenyl) sulfonium hexafluorophosphate, 4- (4-benzoylphenylthio ) Phenyl-di- (4-fluorophenyl) sulfonium hexafluoroantimonate, 4- (4-benzoylphenylthio) phenyl-diphenylsulfonium hexafluorophosphate, 4- (4-benzoylphenylthio) Phenyl-diphenylsulfonium hexafluoroantimonate, 4- (phenylthio) phenyl-di- (4- (β-hydroxyethoxy) phenyl) sulfonium hexafluorophosphate, 4- (phenylthio) phenyl -Di- (4- (β-hydroxyethoxy) phenyl) sulfoniumhexafluoroantimonate, 4- (phenylthio) phenyl-di- (4-fluorophenyl) sulfoniumhexafluorophosphate, 4 -(Phenylthio) phenyl-di- (4-fluorophenyl) sulfoniumhexafluoroantimonate, 4- (phenylthio) phenyl-diphenylsulfonium hexafluorophosphate, 4- (phenylthio) phenyl- Diphenylsulfonium hexafluoro Antimonate, 4- (2-chloro-4-benzoylphenylthio) phenylbis (4-fluorophenyl) sulfoniumhexafluorophosphate, 4- (2-chloro-4-benzoylphenylthio) phenylbis (4 -Fluorophenyl) sulfonium hexafluoroantimonate, 4- (2-chloro-4-benzoylphenylthio) phenyldiphenylsulfonium hexafluorophosphate, 4- (2-chloro-4-benzoylphenylthio) Phenyldiphenylsulfonium hexafluoroantimonate, 4- (2-chloro-4-benzoylphenylthio) phenylbis (4-hydroxyphenyl) sulfonium hexafluorophosphate, 4- (2-chloro-4- Benzoylphenylthio) phenylbis (4-hydroxyphenyl) sulfonium hexafluoroantimonate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, (tolyl cumyl) iodonium hexafluoro Lophosphate, (tolyl cumyl) iodonium hexafluoroantimonate, (tolyl cumyl) iodonium tetrakis (pentafluor Phenyl) borate, bis (tertiarybutylphenyl) iodonium hexafluorophosphate, bis (tertiarybutylphenyl) iodonium hexafluoroantimonate, bis (tertiarybutylphenyl) iodium tetrakis (pentafluorophenyl ) Borate, benzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, benzyl-4-hydroxyphenylmethylsulfonium hexafluoroantimonate, benzyldimethylsulfonium hexafluorophosphate, benzyldimethylsulfonium hexafluoro Roantimonate, p-chlorobenzyl-4-hydroxyphenylmethylsulfonium hexafluorophosphate, p-chlorobenzyl-4-hydroxyphenyl methylsulfonium hexafluoroantimonate, 4-acetoxyphenyldimethylsul Phosphorous hexafluorophosphate, 4-acetoxyphenyldimethylsulfonium hexafluoroantimonate, 4-methoxycarbonyloxyphenyldimethylsulfonium hexafluorophosphate, 4-methoxycarbo Nyloxyphenyldimethylsulfonium hexafluoroantimonate, 4-ethoxycarbonyloxyphenyldimethylsulfonium hexafluorophosphate, 4-ethoxycarbonyloxyphenyldimethylsulfonium hexafluoroantimonate, α-naph Methylmethyldimethylsulfonium hexafluorophosphate, α-naphthylmethyldimethylsulfonium hexafluoroantimonate, α-naphthylmethyltetramethylenesulfonium hexafluorophosphate, α-naphthylmethyltetramethylenesulfonium hexafluoro Roantimonate, cinnamil dimethylsulfonium hexafluorophosphate, cinnamil dimethylsulfonium hexafluoro antimonate, cinnamil tetramethylenesulfonium hexafluorophosphate, cinnamil tetramethylenesulfonium hexafluoroantimonate , N- (α-phenylbenzyl) cyanopyridinium hexafluorophosphate, N- (α-phenylbenzyl) -2-cyanopyridinium hexafluoroantimonate, N-cinnamil-2- Anopyridinium hexafluorophosphate, N-cinnamil-2-cyanopyridinium hexafluoroantimonate, N- (α-naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, N- ( α-naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, N-benzyl-2-cyanopyridinium hexafluorophosphate, N-benzyl-2-cyanopyridinium hexafluoroantimo Nate and the like.

Moreover, as other preferable photocationic polymerization initiator, xylene cyclopentadienyl iron (II) hexafluoro antimonate, cumene cyclopentadienyl iron (II) hexafluoro phosphate, xylene cyclopentadienyl iron Iron / allene complexes, such as (II) -tris (trifluoromethylsulfonyl) metanide, an aluminum complex / photodecomposition silicon compound type initiator, etc. are mentioned.

The photocationic polymerization initiator (B) demonstrated above can be used individually by 1 type or in mixture of 2 or more types, The usage-amount is 1-to 100 parts by weight of all 100 weight part of photocationic curable component (A). Let it be 10 weight%. When the compounding quantity of a photocationic polymerization initiator (B) is too small, hardening of an adhesive will become inadequate and adhesive strength will fall. On the other hand, when the amount is too large, as a result of the increase in the ionic substance in the cured product, the hygroscopicity of the cured product is increased, and the durability performance of the polarizing plate is lowered.

(Other components that can be blended in the photocurable adhesive composition)

A small amount of an organic solvent may be mix | blended with this photocurable adhesive composition in order to improve coating suitability. The organic solvent should just melt | dissolve a photocurable adhesive composition favorably, without reducing the optical performance of a polarizer, and there is no special limitation in the kind. For example, organic solvents such as hydrocarbons typified by toluene and esters typified by ethyl acetate can be used.

This photocurable adhesive composition may further contain polymeric monomers other than an alicyclic epoxy compound (A1) and a diglycidyl compound (A2). As a polymerizable monomer, a cation polymerizable monomer, a radical polymerizable monomer, etc. can be illustrated.

As a cationically polymerizable monomer, oxetane is mentioned, for example. Oxetanes are compounds having a 4-membered ring ether in the molecule, for example, 3-ethyl-3-hydroxymethyloxetane, 1,4-bis [(3-ethyl-3-oxetanyl) methoxy Methyl] benzene, 3-ethyl-3- (phenoxymethyl) oxetane, di [(3-ethyl-3-oxetanyl) methyl] ether, 3-ethyl-3- (2-ethylhexyloxymethyl) jade Cetane, a phenol novolak oxetane, etc. are mentioned. As these oxetane compounds, a commercial item can be obtained easily, For example, as a brand name, "Aron oxetane OXT-101", "Aron oxetane OXT-121", "Aron oxetane OXT-211", "Aron oxetane OXT-221", "Aron oxetane OXT-212" (above, Toa synthesis company make), etc. are mentioned.

Said cationically polymerizable monomer has the effect | action which improves the adhesiveness after hardening of an adhesive agent, and is used in the range which does not affect weather resistance and photocurability as needed.

As a radically polymerizable monomer, for example, an acrylate compound, a methacrylate compound (hereinafter also referred to as (meth) acrylate in the sense including both acrylate and methacrylate), allyl urethane compound, and unsaturated polyester A compound and a styrene type compound are mentioned. When used for the photocurable adhesive agent of this invention, (meth) acrylate is preferable at the point which is easy to acquire and easy to handle. As (meth) acrylate, urethane (meth) acrylate, (poly) ester (meth) acrylate, (poly) ether (meth) acrylate, (meth) acrylate of alcohol, and other (meth) acryl The rate is mentioned.

Here, the urethane (meth) acrylate illustrated as a (meth) acrylate compound is ester compound of polyol and (meth) acrylic acid, such as 1 type, or 2 or more types of (poly) ester polyol, (poly) ether polyol, polyhydric alcohol, etc. (Meth) acrylates obtained by reacting a phosphorus hydroxyl group-containing (meth) acrylate with one or two or more kinds of (poly) isocyanate compounds; Ester which has urethane bonds, such as (meth) acrylate obtained by making polyol, such as 1 or 2 or more types of (poly) ester polyol, (poly) ether polyol, polyhydric alcohol, and hydroxyl-containing (meth) acrylate, and isocyanate react Compound.

As a polyhydric alcohol inducing (poly) ester polyol, for example, 1,3-butanediol, 1,4-butanediol, 1,6-hexanediol, diethylene glycol, triethylene glycol, neopentyl glycol, polyethylene glycol, Polypropylene glycol, polybutylene glycol, trimethylol propane, glycerin, pentaerythritol, dipentaerythritol and the like. As polycarboxylic acid which induces a (poly) ester polyol, adipic acid, terephthalic acid, phthalic anhydride, trimellitic acid, trimesic acid, etc. are mentioned, for example.

As (poly) ether polyol, what added alkylene oxides, such as ethylene oxide, a propylene oxide, butylene oxide, to the polyhydric alcohol mentioned above is mentioned. As a (poly) isocyanate compound, monovalent or divalent or more isocyanate is mentioned, A bivalent or more isocyanate is preferable.

As a divalent or more isocyanate, 2, 4- and / or 2, 6- tolylene diisocyanate, diphenylmethane-4,4'- diisocyanate, p-phenylenedi isocyanate, xylylene diisocyanate, 1, 5- naph Tylene diisocyanate, 3,3'- dimethyl diphenyl-4,4'- diisocyanate, dianisidine diisocyanate, tetramethyl xylylene diisocyanate, isophorone diisocyanate, dicyclohexyl methane-4,4'- diisocyanate , Trans and / or cis-1,4-cyclohexanediisocyanate, norbornene diisocyanate, 1,6-hexamethylene diisocyanate, 2,2,4 and / or (2,4,4) -trimethylhexamethylenedi Isocyanate, lysine diisocyanate, triphenylmethane triisocyanate, 1-methylbenzol-2,4,6-triisocyanate, and dimethyl triphenylmethane tetraisocyanate.

Moreover, (poly) ester (meth) acrylate is an ester compound of the (poly) ester and (meth) acrylic acid which have one or two or more hydroxyl groups in a molecule | numerator. As a (poly) ester which has 1 or 2 or more hydroxyl groups in a molecule | numerator, the ester compound of 1 type, or 2 or more types of polyhydric alcohol, and 1 type, or 2 or more types of monocarboxylic acid or polycarboxylic acid is mentioned. .

As a polyhydric alcohol which induces the (poly) ester which has one or two or more hydroxyl groups in a molecule | numerator, the thing similar to the compound mentioned above is mentioned, As monocarboxylic acid, for example, formic acid, acetic acid, propionic acid, butyric acid Isobutyric acid, valeric acid, caproic acid, caprylic acid, 2-ethylhexanoic acid, benzoic acid and the like. As polycarboxylic acid, the thing similar to the compound mentioned above is mentioned.

(Poly) ether (meth) acrylate is an ester compound of (poly) ether and (meth) acrylic acid which have one or two or more hydroxyl groups in a molecule | numerator. As a (poly) ether which has one or two or more hydroxyl groups in a molecule | numerator, 1 type (s) or 2 or more types of alkylene oxides are added to 2-methoxyethanol, 2-ethoxy ethanol, 2-butoxy ethanol, and a polyhydric alcohol. What is obtained by this is mentioned. As a polyhydric alcohol and alkylene oxide, the same thing as the compound mentioned above is mentioned. Specifically, diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and ethylene oxide modified trimethylolpropane tree (Meth) acrylate, a propylene oxide modified tri methylol propane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, etc. are mentioned.

The (meth) acrylates of alcohols are ester compounds of alcohols (particularly aliphatic alcohols or aromatic alcohols) and (meth) acrylates having one or two or more hydroxyl groups in the molecule. For example, 2-ethylhexyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, isoamyl (meth) acrylate, lauryl (meth) acrylic Laterate, stearyl (meth) acrylate, isooctyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, isobornyl (meth) acrylate, benzyl (meth) acrylate, 1,3-butanediol di ( Meth) acrylate, 1,4-butanedioldi (meth) acrylate, neopentylglycoldi (meth) acrylate, 1,6-hexanedioldi (meth) acrylate, trimethylolpropane tri (meth) acrylate, Pentaerythritol tetra (meth) acrylate etc. are mentioned.

(Epsilon) -caprolactone modified dipentaerythritol hexa (meth) acrylate, a fluorene derivative di (meth) acrylate, carbazole derivative di (meth) acrylate, etc. are mentioned as another acrylate.

The radically polymerizable monomer can be used to control the curing rate.

When using a radically polymerizable monomer as a polymerizable monomer, an optical radical polymerization initiator is also mix | blended. As a radical photopolymerization initiator, ketone compounds, such as an acetophenone type compound, a benzyl type compound, a benzophenone type compound, and a thioxanthone type compound, are mentioned.

As an acetophenone type compound, for example, diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, and 4'-isopropyl-2-hydroxy-2-methylpropiope Paddy, 2-hydroxymethyl-2-methylpropiophenone, 2,2-dimethoxy-1,2-diphenylethan-1-one, p-dimethylaminoacetophenone, P-tert-butyldichloroacetophenone, p-tertiarybutyltrichloroacetophenone, p-azidobenzalacetophenone, 1-hydroxycyclohexylphenylketone, 2-methyl-1- [4- (methylthio) phenyl] -2-morpholinopropanoone -1, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butanone-1, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, benzoin- n-butyl ether, benzoin isobutyl ether, and the like. Examples of the benzyl compounds include benzyl and anylyl. Examples of the benzophenone compounds include benzophenone and o-benzoylbenzoic acid. Methyl, Mihiler Ketone , 4,4'-bisdiethylaminobenzophenone, 4,4'-dichlorobenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, etc. are mentioned, As a thioxanthone type compound, Santone, 2-methyl thioxanthone, 2-ethyl thioxanthone, 2-chloro thioxanthone, 2-isopropyl thioxanthone, 2, 4- diethyl thioxanthone, etc. are mentioned.

These radical photopolymerization initiators can be mix | blended and used 1 type or 2 or more types according to desired performance, Preferably it is 0.05-10 mass%, More preferably, 0.1-10 mass% is mix | blended with respect to a radically polymerizable monomer. . When the compounding quantity of the radical photopolymerization initiator with respect to a radically polymerizable monomer is 0.05 mass% or more, hardening of a photocurable adhesive agent can be advanced more favorably, and when it is 10 mass% or less, it hardens and forms the photocurable adhesive agent of this invention. The physical strength of the adhesive layer is good.

The compound used as a polymerizable monomer may be 1 type, or 2 or more types of mixtures may be sufficient as it. When a photocurable adhesive agent contains polymerizable monomers other than an alicyclic epoxy compound (A1) and a diglycidyl compound (A2), the usage-amount of these polymerizable monomers is 100 weight part to the above-mentioned alicyclic epoxy compound (A1) It is preferable that it is 100 parts by weight or less. When the usage-amount of a polymerizable monomer is 100 weight part or less, when producing a polarizing plate using this photocurable adhesive agent, the adhesive strength of a polarizer and a protective film can be kept favorable. As for the usage-amount of the polymerizable monomer with respect to 100 weight part of alicyclic epoxy compounds (A1), it is more preferable that it is 5 weight part or more, In this case, the modification effect by a polymerizable monomer can be obtained favorably. Moreover, it is more preferable that the usage-amount of a polymeric monomer is 50 weight part or less.

Moreover, this photocurable adhesive agent can be made to contain various additive components in the range which does not impair the effect of this invention. As an additive component, in addition to the above-mentioned radical photopolymerization initiator, a photosensitizer, a thermal cationic polymerization initiator, polyols, an ion trap agent, antioxidant, an optical stabilizer, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, a filler , A flow regulator, a plasticizer, an antifoaming agent, a leveling agent, a dye, an organic solvent, and the like can be blended.

When it contains an additive component, it is preferable that the usage-amount is 1000 weight part or less with respect to 100 weight part of above-mentioned alicyclic epoxy compound (A1). When the usage-amount is 1000 weight part or less, of storage stability by the combination of at least an alicyclic epoxy compound (A1), a diglycidyl compound (A2), and a photocationic polymerization initiator (B) which are essential components of a photocurable adhesive agent, The effect of improving, preventing discoloration, improving the curing speed, and ensuring good adhesiveness can be exhibited satisfactorily.

[Polarizer]

A polarizer and a protective film are bonded together using the above photocurable adhesive composition, and a polarizing plate is manufactured. There is no restriction | limiting in particular in the method of apply | coating a photocurable adhesive agent between a polarizer and a protective film, For example, various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, a gravure coater, can be used. Moreover, after dripping the said photocurable adhesive agent between a polarizer and a protective film, the method of pressurizing with a roll etc. and developing uniformly can also be used. Here, the material of a roll can use a metal, rubber | gum, etc., In the case where the thing which dripped the said photocurable adhesive agent between the polarizer and the protective film is passed between a roll and a roll, and it presses and develops, these rolls may be the same material, Different materials may be used. The thickness of an adhesive bond layer is 50 micrometers or less normally, Preferably it is 20 micrometers or less, More preferably, it is 10 micrometers or less.

In this way, the protective film which has transparency is bonded together on the adhesive bond layer formed by the photocurable adhesive agent. The protective film used here is not specifically limited, Specifically, the acetyl cellulose type film, such as triacetyl cellulose currently widely used as a protective film of a polarizing plate, and the film of transparent resin with a water vapor transmission rate lower than triacetyl cellulose can be used. The water vapor transmission rate of triacetyl cellulose is generally about 400 g / m 2/24 hr. When bonding a protective film on both surfaces of a polarizer, two protective films may be bonded one by one on a single stage, or both surfaces may be bonded in one step.

As an acetyl cellulose type film used by this invention, in addition to the above-mentioned triacetyl cellulose film, a diacetyl cellulose film, an acetyl butyl cellulose film, etc. are mentioned.

As an example of the transparent resin film with low water vapor transmission rate used by this invention, an amorphous polyolefin resin film, a polyester resin film, an acrylic resin film, a polycarbonate resin film, a polysulfone resin film, an alicyclic polyimide resin A film etc. are mentioned. In these, the film which consists of amorphous polyolefin resin is used especially preferably. The amorphous polyolefin resin usually has a polymerized unit of a cyclic olefin such as a norbornene or a polycyclic norbornene monomer, and may be a copolymer of a cyclic olefin and a chain olefin. Especially, thermoplastic saturated norbornene-type resin is typical. It is also effective that a polar group is introduced. Commercially available amorphous polyolefin resins include "Aton" from JSR, "ZEONEX" and "ZEONOR" from Nippon Xeon, "APO" and "Apel" from Mitsui Chemicals. Although amorphous polyolefin resin is made into a film to make a film, well-known methods, such as a solvent casting method and a melt extrusion method, are used suitably for film formation.

In this invention, one of the preferable forms is that a protective film has a water vapor transmission rate of 300 g / m <2> / 24 hr or less which consists of amorphous polyolefin resin.

When bonding a protective film on both surfaces of a polarizer, both may be the same kind and may be a different kind. When bonding different kinds of protective films on both surfaces of a polarizer, as one protective film, the above-mentioned amorphous polyolefin resin film, polyester resin film, acrylic resin film, polycarbonate resin film, polysulfone resin film, Resin films with low moisture permeability, such as an alicyclic polyimide resin film, can be used, As other protective film, In addition to these, Cellulose acetate type films, such as the above-mentioned triacetyl cellulose film, a diacetyl cellulose film, an acetyl butyl cellulose film You can also use Moreover, when forming the protective film which consists of a resin film with a relatively high moisture permeability like a cellulose acetate type film in one surface of a polarizer in this way, it is epoxy type, such as a polyvinyl alcohol-type adhesive agent, on the bonding surface of such a resin film with high moisture permeability. You may use adhesives other than this.

Prior to bonding to a polarizer, the protective film may be subjected to easy adhesion treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment, and the like on the bonding surface. Moreover, you may have various process layers, such as a hard-coat layer, an antireflection layer, an glare-proof layer, on the surface on the opposite side to the bonding surface with respect to the polarizer of a protective film. The thickness of a protective film is the range of about 5-200 micrometers normally, Preferably it is 10-120 micrometers, More preferably, it is 10-85 micrometers.

As described above, the polarizer having the protective film bonded to the polarizer via the uncured adhesive layer is then irradiated with an active energy ray to cure the adhesive layer made of the epoxy resin composition to fix the protective film onto the polarizer.

Although the light source of an active energy ray is not specifically limited, For example, low pressure mercury lamp, medium pressure mercury lamp, high pressure mercury lamp, ultrahigh pressure mercury lamp, chemical lamp, black light lamp, microwave excitation mercury lamp, metal halide which has luminescence distribution in wavelength 400 nm or less Lamps and the like can be used. Although light irradiation intensity | strength with respect to an epoxy resin composition is determined for every target composition, although it does not specifically limit, It is preferable that irradiation intensity of the wavelength range effective for activation of an initiator is 0.1-100 dl / cm <2>. If the light irradiation intensity to the resin composition is less than 0.1 mW / cm 2, the reaction time becomes too long, and if it exceeds 100 mW / cm 2, the yellowing of the epoxy resin composition is caused by heat radiated from the lamp and the exotherm during polymerization of the composition. And deterioration of the polarizer may be generated. Although light irradiation time with respect to a composition is controlled for every composition to harden, it does not specifically limit, It is preferable to set so that accumulated light quantity represented by the product of irradiation intensity and irradiation time may be 10-5,000 mJ / cm <2>. If the amount of accumulated light to the epoxy resin composition is less than 10 mJ / cm 2, the generation of active species derived from the initiator may not be sufficient, and curing of the resulting protective film may be insufficient, while the amount of accumulated light exceeds 5,000 mJ / cm 2. In this case, irradiation time becomes very long, which is disadvantageous for productivity improvement.

In curing a photocurable adhesive agent by irradiation of an active energy ray, it is preferable to harden | cure in the range which all the functions of a polarizing plate, such as polarization degree, a transmittance | permeability, a color, and transparency of a protective film, do not fall.

[Laminated Optical Member]

When using a polarizing plate, it can also be set as the optical member which provided the optical layer which shows optical functions other than a polarizing function through the protective film layer of this invention. As an optical layer laminated | stacked on a polarizing plate for the purpose of formation of an optical member, there exist some used for formation of a liquid crystal display device, such as a reflection layer, a semi-transmissive reflection layer, a light-diffusion layer, a retardation plate, a light collecting plate, a brightness enhancement film, etc., for example. The reflective layer, semi-transmissive reflective layer, and light diffusing layer are used when forming an optical member made of a reflective, semi-transmissive, diffused, or two-way polarizing plate.

A reflective polarizing plate is used for a liquid crystal display device of the type which reflects and displays incident light on the viewer's side, and since a light source such as a backlight can be omitted, it is easy to thin the liquid crystal display device. In addition, the transflective polarizing plate is used for a liquid crystal display device of a type which displays a reflection type at a spot and a light source such as a backlight at a dark spot. The optical member as a reflective polarizing plate can, for example, attach and form a foil or a vapor deposition film made of a metal such as aluminum to a protective film on the polarizer to form a reflective layer. The optical member as a semi-transmissive polarizing plate can be formed by making the said reflective layer into a half mirror, or sticking the reflecting plate which contains a pearl pigment etc. and shows light transmittance to a polarizing plate. On the other hand, the optical member as a diffusion type polarizing plate has various methods, such as the method of performing a mat process to the protective film on a polarizing plate, the method of apply | coating resin containing microparticles, and the method of adhering the film containing microparticles | fine-particles. To form a fine uneven structure on the surface.

In addition, formation of the optical member as a polarizing plate for both reflection and diffusion can be performed by the method of forming the reflective layer in which the uneven structure was reflected in the fine uneven structure surface of a diffused polarizing plate, for example. The reflective layer having a fine concave-convex structure has the advantage of diffusing incident light by diffuse reflection, preventing directivity and glare, and suppressing unevenness in light and dark. Moreover, the resin layer and the film containing microparticles | fine-particles also have the advantage that they can spread | diffuse when incident light and the reflected light permeate | transmit the microparticles-containing layer, and can suppress more light intensity nonuniformity. The reflective layer reflecting the surface fine concavo-convex structure can be formed by directly attaching and forming a metal to the surface of the fine concavo-convex structure, for example, by a method such as vacuum deposition, ion plating, sputtering, or plating. As microparticles | fine-particles mix | blended in order to form surface fine uneven | corrugated structure, it consists of silica, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide etc. which have an average particle diameter of 0.1-30 micrometers, for example. Organic fine particles made of inorganic fine particles, crosslinked or uncrosslinked polymers, and the like can be used.

On the other hand, the retardation plate as the optical layer is used for the purpose of compensating for the retardation by the liquid crystal cell. As an example, the birefringent film which consists of stretched films of various plastics, the film in which the discotic liquid crystal and the nematic liquid crystal were orientated, and the said liquid crystal layer were formed on the film base material, etc. are mentioned. In this case, as a film base material which supports an orientation liquid crystal layer, cellulose type films, such as a triacetyl cellulose, are used preferably.

As a plastic which forms a birefringent film, polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyolefin like polypropylene, polyarylate, polyamide, etc. are mentioned, for example. The stretched film may be processed by a suitable method such as uniaxial or biaxial. Moreover, the birefringent film which controlled the refractive index of the thickness direction of a film by applying shrinkage force and / or extending | stretching force under adhesion with a heat shrinkable film may be sufficient. In addition, you may use a phase difference plate combining two or more sheets for the purpose of control of optical characteristics, such as widening.

A light collecting plate is used for the purpose of optical path control, etc., and can be formed as a prism array sheet, a lens array sheet, a dot formation sheet | seat, etc.

The brightness enhancing film is used for the purpose of improving the brightness in a liquid crystal display device. For example, a reflective polarization separating sheet and a collet designed to produce anisotropy in reflectance by laminating a plurality of thin films having different refractive anisotropy. The circularly polarized light separating sheet which supported the oriented film of the sterile liquid crystal polymer, or the oriented liquid crystal layer on the film base material, etc. are mentioned.

The optical member is a combination of a polarizing plate and one or two or more layers of optical layers selected according to the purpose of use in the above-described reflective layer to semi-transmissive reflective layer, light diffusing layer, retardation plate, light collecting plate, brightness enhancement film, and the like. It can be set as a laminate. In that case, two or more layers of optical layers, such as a light-diffusion layer, a phase difference plate, a light collecting plate, and a brightness enhancement film, may be arrange | positioned, respectively. In addition, there is no limitation in particular in arrangement | positioning of each optical layer.

Although various optical layers which form an optical member are integrated using an adhesive agent, the adhesive agent used for it is not specifically limited as long as an adhesive layer is formed satisfactorily. It is preferable to use an adhesive (it is also called a pressure-sensitive adhesive) from a viewpoint of the simplicity of an adhesion | attachment operation, the prevention of the occurrence of optical deformation, etc. An acrylic polymer, a silicone polymer, polyester, polyurethane, polyether, etc. can be used for the adhesive as a base polymer. Among them, like the acrylic pressure-sensitive adhesive, it is excellent in optical transparency, maintains proper wettability and cohesion, and is excellent in adhesiveness to the substrate, and furthermore has weather resistance, heat resistance, and the like, and peeling such as lifting or peeling under conditions of heating or humidification. It is preferable to select and use what does not cause a problem. In an acrylic adhesive, the functional group containing acrylic monomer which consists of alkyl ester of (meth) acrylic acid which has a C20 or less alkyl group, such as a methyl group, an ethyl group, and a butyl group, and (meth) acrylic acid, (meth) acrylic-acid hydroxyethyl, etc., An acrylic copolymer having a weight average molecular weight of 100,000 or more, which is blended so that the glass transition temperature is preferably 25 ° C. or less, more preferably 0 ° C. or less, is useful as the base polymer.

Formation of an adhesive layer with respect to a polarizing plate, for example, melt | dissolves or disperse | distributes an adhesive composition in organic solvents, such as toluene and ethyl acetate, prepares a 10-40 weight% solution, apply | coats this directly on a polarizing plate, and forms an adhesive layer It can carry out by the method of forming, the method of forming an adhesive layer by forming an adhesive layer in advance on a protective film, and sticking it on a polarizing plate. Although the thickness of an adhesive layer is determined by the adhesive force etc., the range of about 1-50 micrometers is suitable.

Moreover, the filler, pigment, colorant, antioxidant, ultraviolet absorber, etc. which consist of glass fiber, glass beads, resin beads, a metal powder, other inorganic powder, etc. may be mix | blended with the adhesion layer as needed. Examples of the ultraviolet absorber include salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex salt compounds and the like.

The optical member can be disposed on one side or both sides of the liquid crystal cell. The liquid crystal cell to be used is arbitrary, for example, a liquid crystal display device using various liquid crystal cells, such as an active matrix drive type | mold represented by a thin-film transistor type and the simple matrix drive type represented by a super twisted nematic type | mold. Can be formed. The optical members formed on both sides of the liquid crystal cell may be the same or different.

Example

Although an Example is shown to the following and this invention is demonstrated to it further more concretely, this invention is not limited by these Examples. In the examples,% and parts representing the content to the amount used are based on weight unless otherwise specified. First, the reference example which produced the polyethylene terephthalate film with an anti-glare layer used as one protective film of a polarizer is shown.

[Reference Example] (Preparation of polyethylene terephthalate film having an antiglare layer)

Each following component was melt | dissolved in ethyl acetate at 60% of solid content concentration, and the ultraviolet curable resin composition which gives the refractive index of 1.53 after hardening was prepared.

Pentaerythritol triacrylate 60 parts

Multifunctional urethane acrylate ^* 40 parts

^* Polyfunctional urethane acrylate: The reaction product of hexamethylene diisocyanate and pentaerythritol triacrylate.

Next, with respect to 100 parts of solid content of this ultraviolet curable resin composition, 2 parts of porous silica particles [brand name "Sirisia", the product of Fuji Silysia Chemical Co., Ltd.], and 2,4,6-trimethylbenzoyl which are a photoinitiator are next. Five parts of diphenylphosphine oxide (brand name "Lucirine TPO", BASF Corporation make) were added, and the coating liquid for antiglare layers was prepared.

This coating liquid is apply | coated to the surface (surface which consists of polyethylene terephthalate itself) which has an easily bonding layer on single side | surface, and the easily bonding layer of the 38-micrometer-thick biaxially-stretched polyethylene terephthalate film is not formed, and is ultraviolet curable resin A composition layer was formed and it dried for 3 minutes in the dryer set to 80 degreeC. From the ultraviolet curable resin composition layer side of the film after drying, light of a high pressure mercury lamp is irradiated so that light intensity may be 250 mW / cm <2> and a cumulative light amount will be 300 mJ / cm <2> as UVA (315-400 nm) wavelength, and ultraviolet curable resin The composition layer was hardened and the anti-glare film which consists of a laminated body of the 5-micrometer-thick anti-glare layer (hardening resin) and biaxially stretched polyethylene terephthalate film which has unevenness | corrugation on the surface was obtained. The haze value of this anti-glare film was measured using the haze transmittance meter "HM-150" (made by Murakami Color Technology Research Institute), and the haze value of 10% was obtained.

Next, the photocurable adhesive composition is prepared, and the Example and comparative example applied to preparation of a polarizing plate are shown. The photocationic curable component and photocationic polymerization initiator used by the following examples are as follows, and are represented by each symbol below.

(A) photocationic curable component

(A1) alicyclic epoxy compound

a1: 3, 4- epoxycyclohexyl methyl 3, 4- epoxy cyclohexane carboxylate

(A2) diglycidyl compound

a21: 1,4-butanediol diglycidyl ether (chlorine content 0.5%)

a21c: 1,4-butanediol diglycidyl ether (chlorine content 8.0%)

a22: neopentyl glycol diglycidyl ether (chlorine content 0.5%)

a22c: neopentyl glycol diglycidyl ether (chlorine content 8.1%)

a23: cyclohexane dimethanol diglycidyl ether (chlorine content 0.4%)

a23c: cyclohexane dimethanol diglycidyl ether (chlorine content 7.7%)

(B) photocationic polymerization initiator (it abbreviates as "initiator" in a table)

(b1) triarylsulfonium hexafluorophosphate

[Examples 1-6 and Comparative Examples 1-5]

(1) Preparation of Photocurable Adhesive Composition

After mixing the photocationic curable component and the photocationic polymerization initiator in the mixing | blending ratio shown in Table 1, respectively, it defoamed and prepared the photocurable adhesive liquid. In addition, the photocationic polymerization initiator (b1) was mix | blended as a 50% propylene carbonate solution, and it showed in Table 1 by the solid content.

(2) Measurement of chlorine concentration of adhesive before curing

The chlorine concentration contained in each adhesive liquid prepared above was measured as follows. That is, each adhesive liquid is first decomposed into a combustion apparatus "TOX-100" (manufactured by Dia Instruments Co., Ltd.), and the gas is collected in the absorbent liquid, and then by an ion chromatograph apparatus "ICS-2000" (manufactured by Dionex Corporation). The amount of chlorine was determined, and the chlorine concentration was calculated from the amount of the adhesive liquid used for the first decomposition. Each chlorine concentration measurement result is shown in Table 1.

(3) Measurement of storage elastic modulus at 80 degreeC of hardened | cured material

On one side of a polyethylene terephthalate film [trade name "Toyobo Ester Film E7002", manufactured by Toyo Spinning Co., Ltd.] having no easy bonding layer on its surface, using an applicator [bar coater, Dai-ichi Chemical Co., Ltd.] Each adhesive liquid prepared in said (1) was apply | coated so that the film thickness after hardening might be set to about 25 micrometers. Next, the ultraviolet-ray was irradiated and the adhesive hardened | cured so that the accumulated light amount might be set to 3000 mJ / cm <2> by "D valve" by Fusion UV Systems. This was cut | judged to the magnitude | size of 5 mm x 30 mm, the polyethylene terephthalate film was peeled off, and the cured film of an adhesive agent was obtained. And using the dynamic viscoelasticity measuring apparatus "DVA-220" made from Haiti Measuring Instrument Co., Ltd., the above-mentioned cured film is gripped at a spacing of 2 cm between the grippers so that the long side thereof becomes the tensile direction, and the frequency of tension and shrinkage. The storage modulus at a temperature of 80 ° C. was set at 1 Pa and a temperature increase rate of 3 ° C./min. The results are shown in Table 1.

(4) Production of Polarizer

A corona discharge treatment was performed on the surface of a triacetyl cellulose film (trade name "Fuji-Tak", manufactured by Fuji Film Co., Ltd.) having a thickness of 80 µm containing a ultraviolet absorber, and a bar coater was used on the corona discharge treatment surface. Each adhesive liquid prepared in said (1) was apply | coated so that the film thickness after hardening might be set to about 3 micrometers. The polyvinyl alcohol-iodine type polarizer was bonded to this adhesive bond layer. On the other hand, the corona discharge treatment is given to the surface (easy bonding layer surface) on the opposite side to the glare-proof layer of the 43-micrometer-thick biaxially-stretched polyethylene terephthalate film which has an anti-glare layer produced by the reference example, and to the corona discharge treatment surface, The same adhesive liquid as above was apply | coated with the bar coater so that the film thickness after hardening might be set to about 3 micrometers. The triacetyl cellulose film produced above was bonded to this adhesive bond layer, and the polarizer side of the polarizer bonded on one side was bonded together, and the laminated body was produced. From the biaxially stretched polyethylene terephthalate film side which has an anti-glare layer of this laminated | multilayer, the accumulated light amount is 750 mJ / cm <2> by the "D valve" by a fusion UV system company using the ultraviolet irradiation device with a belt conveyor. Ultraviolet rays were irradiated to harden the adhesive. In this way, the polarizing plate in which the protective film was bonded to both surfaces of the polarizer was produced.

(5) Evaluation of Durability of Polarizing Plate by Cold Impact Test

The polarizing plate produced in the above (4) was cut to a size of 170 mm × 110 mm, an acrylic pressure-sensitive adhesive layer having a thickness of 25 µm was formed on the triacetyl cellulose film side, the pressure-sensitive adhesive layer was attached to a glass plate, and a cold heat shock test (heat Shock test). The cold shock test was performed by holding the polarizing plate sample bonded to the said glass plate at -35 degreeC for 1 hour, then heating up to 70 degreeC as 1 cycle, and repeating this for 30 cycles in total. This test was performed about each sample of 6 polarizing plates, and it evaluated by the ratio with respect to the total number of samples (6) of which a crack was observed in the polarizer after a test. The results are shown in Table 1.

As shown in Table 1, in the photocurable adhesive composition which made the alicyclic epoxy compound (A1) in a photocationic curable component (A) 50 to 60%, and the diglycidyl compound (A2) 50 to 40%, As a diglycidyl compound (A2), 1, 4- butanediol diglycidyl ether (a21c), neopentyl glycol diglycidyl ether (a22c), or cyclohexane dimethanol diglycisy which are all high in chlorine content Comparative Examples 2-5 using a diether (a23c) showed only the low storage elastic modulus of the hardened | cured material of an adhesive agent, and when it was set as a polarizing plate, the polarizer was easy to crack by cold heat shock test.

On the other hand, 1,4-butanediol diglycidyl ether (a21), neopentylglycol diglycidyl ether (a22) or cyclohexane dimethanol diglycidyl ether (a23) which all made the chlorine content low were used Examples 1-6 showed that the hardened | cured material of the adhesive agent combined with an alicyclic epoxy compound (A1) showed a high storage elastic modulus, and when the polarizing plate was used, it was confirmed that the crack of a polarizer can be prevented effectively.

In addition, when the 1, 4- butanediol diglycidyl ether (a21) with little chlorine content is used, the adhesive agent of the comparative example 1 which made the compounding quantity 50% in the photocationic curable component (A) has the storage elastic modulus of hardened | cured material. When it was set as this polarizing plate, it was the state which a polarizer was likely to crack by a cold shock test. Thus, depending on the kind of diglycidyl compound (A2), even if it reduces chlorine content, when the compounding quantity of the said diglycidyl compound (A2) in a photocationic curable component (A) becomes 50% vicinity, Although the hardened | cured material may not provide sufficient storage elastic modulus, alicyclic epoxy compound (A1) and diglycid so that hardened | cured material may exhibit a storage elastic modulus of 1000 Mpa or more in 80 degreeC, as prescribed | regulated by this invention. It turns out that what is necessary is to combine a dill compound (A2).

In Examples 1 to 6, the amount of the alicyclic epoxy compound (A1 = a1) in the photocationic curable component (A) is increased to 70% or 80%, and the remainder is a diglycidyl compound having a small amount of chlorine (a21). , a22 or a23), the viscosity of the adhesive liquid rises correspondingly, but is suppressed to a viscosity that can be applied at room temperature, and when the cured product gives a high storage modulus and is used as a polarizing plate, cracks of the polarizer are also obtained. Can be effectively prevented.

Claims (6)

As a polarizing plate comprised from the polarizer which consists of a polyvinyl alcohol-type resin film by which a dichroic dye was adsorption-oriented, and the protective film which consists of a transparent resin bonded together at least one surface of this polarizer through an adhesive agent,
Preferably,
100 parts by weight of the photocationic curable component (A),
1-10 weight part of photocationic polymerization initiators (B) are contained,
The said photocationic curable component (A) is based on the total amount,
50 to 95% by weight of an alicyclic epoxy compound (A1) having two or more epoxy groups in the molecule, at least one of which is bonded to an alicyclic ring, and
As chlorine content is 1 weight% or less, following formula (I):
[Chemical Formula 1]

(Wherein Z is a divalent aliphatic group represented by an alkylene group having 1 to 9 carbon atoms, an alkylidene group having 3 or 4 carbon atoms, a divalent alicyclic hydrocarbon group, or a formula -C _m H _2m -Z ¹ -C _n H _2n- ). Group, wherein -Z ¹ -represents -SO _2- , -SO- or -CO-, and m and n each independently represent an integer of 1 or more, but the sum of both is 9 or less)
The polarizing plate which contains 5-50 weight% of diglycidyl compound (A2) shown by this, and whose hardened | cured material shows the storage elastic modulus more than 1000 Mpa in 80 degreeC. The method of claim 1,
The protective film bonded to at least one surface of a polarizer is a polarizing plate which consists of acetyl cellulose resin. The method of claim 1,
The protective film bonded to at least one surface of a polarizer is a polarizing plate which consists of transparent resin chosen from the group which consists of amorphous polyolefin resin, polyester resin, polycarbonate resin, and chain-type polyolefin resin. The method of claim 1,
A protective film made of acetyl cellulose resin is bonded to one surface of the polarizer via the adhesive, and on the other side of the polarizer, amorphous polyolefin resin, polyester resin, polycarbonate resin and chain polyolefin type. The polarizing plate which the protective film which is a film which consists of transparent resin selected from the group which consists of resin is bonded through the said adhesive agent. The laminated optical member which consists of a laminated body of the polarizing plate of Claim 1, and another optical layer. The method of claim 5, wherein
The optical layer is a laminated optical member comprising a retardation film.