JP5446902B2 - Cationic polymerizable adhesive and polarizing plate obtained using the same - Google Patents

Description

  The present invention relates to a cationic polymerizable adhesive that can be used in various applications including the production of optical members such as polarizing plates.

  As a polarizing plate used for a liquid crystal display or the like, generally, a polarizer made of a polyvinyl alcohol film impregnated with a dichroic material such as iodine is added to a transparent film made of triacetyl cellulose or a thermoplastic saturated norbornene resin. A laminate of various protective films is known. The adhesive used for bonding the polarizer and the protective film has excellent normal adhesive strength for both adherends of the polarizer and the protective film, and is caused by the backlight of the liquid crystal display, etc. The industry demands that excellent normal adhesive strength to the polarizer and the protective film can be maintained for a long period of time regardless of the influence of light and heat.

  On the other hand, as an adhesive, in recent years, a cationic polymerizable adhesive that is difficult to cause curing inhibition due to oxygen in the atmosphere and that can proceed with a curing reaction even after the supply of energy such as ultraviolet rays is stopped has attracted attention. Application to the adhesive application between the polarizer and the protective film is also being studied.

  For example, as an adhesive used for bonding the polarizer and the protective film, an adhesive made of a composition mainly composed of an epoxy resin that does not contain an aromatic ring is known. An adhesive containing an epoxy resin, an alicyclic epoxy resin, an aliphatic epoxy resin, and a photocationic polymerization initiator is known (see, for example, Patent Document 1).

  However, the normal adhesive strength for polarizers made of polyvinyl alcohol or the like of the adhesive is not one step beyond the level required by the industry, and the normal adhesive strength due to the influence of light and heat caused by the backlight, etc. In some cases, the polarizer and the protective film may be peeled off in a relatively short period of time due to a decrease in the time.

  In this way, along with the development competition for liquid crystal displays that can display even clearer images, the optical components that make up the LCD are required to have very high levels of properties. The actual situation is that no cationically polymerizable adhesive capable of maintaining an excellent normal adhesive strength at a level that can be used for an application has been found for a long time.

JP 2004-245925 A

  The problem to be solved by the present invention is a cationic polymerizable adhesive capable of maintaining excellent normal adhesive strength for a long period of time regardless of the influence of heat, light, etc., and a polarizer and a protective film using the adhesive. It is to provide a polarizing plate to which is adhered.

In order to investigate the above problems, the present inventors have examined combinations of various compounds known as cationically polymerizable compounds such as a hydroxyl group-containing compound, an oxetanyl group-containing compound, and an alicyclic epoxy compound.
Specifically, an adhesive that combines a relatively low-molecular-weight oxetanyl group-containing compound, an aromatic glycidyl ether, and a photocationic polymerization initiator was studied. With such an adhesive, however, the normal adhesive strength decreased over time. It was difficult to prevent enough.
Accordingly, the present inventors examined various combinations of the above-mentioned cationically polymerizable compound and various amounts of residual chlorine that can be contained in the obtained adhesive, and found that a low molecular weight oxetane compound and an aromatic glycidyl were used. It has been found that among adhesives containing ether and a cationic polymerization initiator, an adhesive in which the chlorine remaining in the total amount of the adhesive is 1500 ppm or less can solve the problems of the present invention.
That is, the present invention is an adhesive containing an oxetane compound (A) having a molecular weight of 100 to 800 having two or more oxetanyl groups, an aromatic glycidyl ether (B), and a cationic polymerization initiator (C). The adhesive further contains an oxetane compound (D) having one oxetanyl group and an alicyclic epoxy compound (E) having a structure represented by the following general formula (7), and the oxetane compound (A) And the usage-amount of (D) is the range of 20-70 mass% with respect to the whole quantity of a cation polymeric adhesive, and the usage-amount of the said aromatic glycidyl ether (B) is in the whole quantity of a cation polymeric adhesive. 5 to 50% by mass, and the amount of the cationic polymerization initiator (C) used is in the range of 0.1 to 20% by mass with respect to the total amount of the cationic polymerizable adhesive. Remain Chlorine is related cationic polymerizable adhesive and polarizer obtained by bonding the polarizer and the protective film using the same and equal to or less than 1500 ppm.

  The cationic polymerizable adhesive of the present invention can exhibit excellent normal adhesive strength over a long period of time regardless of the influence of heat, light, etc., so that it can adhere to optical materials such as polarizing plates, construction materials, and automotive interior and exterior parts. It can be suitably used for the agent. In addition, the cationic polymerizable adhesive of the present invention can be used exclusively for the production of a polarizing plate because it has a good normal adhesive strength with respect to a polyvinyl alcohol film generally used for a polarizer material. It can be suitably used for adhesion between a polarizer constituting a polarizing plate and a protective film.

  The present invention relates to an oxetane compound (A) having a molecular weight of 100 to 800 having two or more oxetanyl groups, an aromatic glycidyl ether (B), a cationic polymerization initiator (C), and other additives as necessary. A cationically polymerizable adhesive in which the chlorine remaining in the total amount of the adhesive is 1500 ppm or less, and exclusively for adhesion between the polarizer constituting the polarizing plate and the protective film It can be used suitably. In addition, the said molecular weight shows what is calculated | required by calculating based on a formula weight.

  As the oxetane compound (A) used in the present invention, it is important to use a compound having a molecular weight of 100 to 800. In order to sufficiently cure the polarizer and the protective film, the thickness of the adhesive layer is usually a thin film (several μm thick) in many cases, and the adhesive is uniformly applied with the above-mentioned thickness. In order to do so, the adhesive must have a low viscosity. And in order to obtain the said low-viscosity adhesive agent, it becomes essential to use the above-mentioned comparatively low molecular weight oxetane compound. Instead of the oxetane compound (A), for example, an adhesive obtained by using an oxetane compound having a molecular weight of about 1500 has a relatively high viscosity, so that it is difficult to form a thin film and the adhesive layer has a curable composition. It may cause a decrease or a decrease in adhesive strength.

  As the oxetane compound (A), it is more preferable to use a compound having a molecular weight in the range of 100 to 500 from the viewpoint of further improving the coating workability and curability of the cationic polymerization adhesive of the present invention. It is particularly preferred to use those having a molecular weight in the range of ~ 400.

  Moreover, as said oxetane compound (A), using what has 2 or more of the oxetane ring structure which contributes to cationic polymerization, Preferably it is 2-4 gives favorable curability and normal state adhesive strength. In addition, it is preferable.

  Specifically as an oxetane compound (A) used by this invention, the compound shown, for example by the following general formula (1), (2) etc. can be used independently, or 2 or more types can be used together.

R ₁ in the above general formulas (1) and (2) is each independently a hydrogen atom, a linear, branched or cyclic alkyl group having 1 to 6 carbon atoms, an allyl group, an aryl group, an aralkyl group. , A furyl group or a thienyl group, each R ₂ independently represents a divalent organic residue, and each Z independently represents an oxygen atom or a sulfur atom.

Examples of the linear, branched or cyclic alkyl group having 1 to 6 carbon atoms represented by R ₁ in the general formulas (1) and (2) include a methyl group, an ethyl group, n- or i- A propyl group, an n-, i- or t-butyl group, a pentyl group, a hexyl group, a cyclohexyl group, and the like, and examples of the aryl group include a phenyl group, a naphthyl group, a tolyl group, a xylyl group, and the like. Examples of the group include benzyl and phenethyl groups.

Examples of the divalent organic residue represented by R ₂ in the general formula (1) include a linear, branched or cyclic alkylene group and a poly (oxy) having 4 to 30 carbon atoms. Alkylene) group, phenylene group, xylylene group, and structures represented by the following general formulas (3) and (4).

The linear, branched or cyclic alkylene group constituting R ₂ in the general formula (1) is methylene group, ethylene group, 1,2- or 1,3-propylene group, butylene group, cyclohexylene. An alkylene group having 1 to 15 carbon atoms such as a group is preferable. The poly (oxyalkylene) group having 4 to 30 carbon atoms is preferably one having 4 to 8 carbon atoms, for example, a poly (oxyethylene) group or a poly (oxypropylene) group. Is preferred.

R ₃ in the general formula (3) represents an oxygen atom, a sulfur atom, CH ₂ , NH, SO, SO ₂ , C (CF ₃ ) ₂ or C (CH ₃ ) ₂ .

R ₄ in the general formula (4) represents an alkylene group having 1 to 6 carbon atoms, an arylene group, and a functional group represented by the following general formula (5).

  In the general formula (5), a represents an integer of 1 to 6, and b represents an integer of 1 to 15.

  As said general formula (5), it is preferable that b is an integer of 1-3.

  Examples of the oxetane compound having 2 to 4 oxetane ring structures include Aron Oxetane OXT-221, Aron Oxetane OXT-121, Aron Oxetane OXT-223 (above, manufactured by Toagosei Co., Ltd.), Etanacol OXBP (above , Ube Industries, Ltd.) are commercially available.

As the oxetane compound (A), those represented by the general formula (1) are preferably used, and in particular, bis [1-] wherein R ₁ in the general formula (1) is an ethyl group and R ₂ is methylene. The use of ethyl (3-oxetanyl)] methyl ether can reduce the film thickness of the adhesive after curing, thereby further improving the curability and reducing the adhesive strength due to heat, light, etc. This is preferable because it can be prevented for a long time.

  In the present invention, in addition to the oxetane compound (A) having two or more oxetanyl groups, if necessary, the oxetane compound (D) having one oxetanyl group may be used in combination with a polarizer. It is preferable from the viewpoint of ensuring a sufficient open time for bonding with the protective film and preventing peeling due to heat, light or the like for a long time from the polarizing plate obtained by bonding them. In particular, the equivalent ratio of the oxetanyl group of the oxetane compound (A) and the oxetanyl group of the oxetane compound (D) [the oxetanyl group of (A) / the oxetanyl group of (D)] is 0.1 to 35. It is preferably 0, more preferably 0.2 to 10.0, and particularly preferably 1 to 5.

  As the oxetane compound (D) having one oxetanyl group, for example, a compound represented by the following general formula (6) can be used.

(R ₁ in the general formula (6) represents a hydrogen atom, an alkyl group having 1 to 8 carbon atoms, an alkoxyalkyl group having 1 to 5 carbon atoms, or a hydroxyalkyl group having 1 to 6 carbon atoms. R ₂ represents a hydrogen atom, an optionally branched alkyl group having 1 to 10 carbon atoms, an aliphatic cyclic structure, or an aromatic structure.)

Examples of the alkyl group having 1 to 8 carbon atoms that can constitute R ₁ in the general formula (6) include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, and a 2-ethylhexyl group. Is mentioned.

Examples of the alkoxyalkyl group having 1 to 5 carbon atoms that can constitute R ₁ in the general formula (6) include a methoxymethyl group, an ethoxymethyl group, a propoxymethyl group, a methoxyethyl group, and an ethoxyethyl group. And propoxyethyl group.

Examples of the hydroxyalkyl group having 1 to 6 carbon atoms that can constitute R ₁ in the general formula (6) include a hydroxymethyl group, a hydroxyethyl group, and a hydroxypropyl group.

The optionally branched alkyl group having 1 to 10 carbon atoms that can constitute R ₂ in the general formula (6) is a linear alkyl group such as a methyl group, an ethyl group, or a propyl group. And a branched alkyl group such as a 2-ethylhexyl group.
As the aliphatic cyclic structure may constitute R ₂ in the general formula (6), such as cyclohexyl group and the like. The cyclohexyl group or the like may have an alkyl group or the like instead of a hydrogen atom.
The aromatic structure may constitute R ₂ in the general formula (6), for example, a phenyl group and the like. The phenyl group or the like may have an alkyl group or the like instead of a hydrogen atom.

As said oxetane compound (D), it is preferable to use what has a molecular weight of 100-500, and it is preferable to use what has a molecular weight of 150-500.
Examples of the oxetane compound (D) include 3-hydroxymethyl-3-ethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and 3 It is more preferable to use one or more selected from the group consisting of -ethyl-3- (cyclohexyloxy) methyloxetane.

  In this invention, it is preferable to use the said oxetane compounds (A) and (D) in the range of 20-70 mass% with respect to the whole quantity of a cationically polymerizable adhesive agent. Further, bis [1-ethyl (3-oxetanyl)] methyl ether is used as the oxetane compound (A), preferably 20 to 70% by mass with respect to the total amount of the oxetane compounds (A) and (D). And, as the oxetane compound (D), 3-hydroxymethyl-3-ethyloxetane is preferably used in combination at 20 to 70% by mass with respect to the total amount of the oxetane compounds (A) and (D). This is preferable because improvement in curability and reduction in adhesive strength due to heat, light, and the like can be prevented for a long period of time.

  Next, the aromatic glycidyl ether (B) used in the present invention will be described.

  In this invention, aromatic glycidyl ether (B) is used as what can be ring-opened by the cationic polymerization initiator (C) mentioned later and can form a crosslinked structure.

  As the aromatic glycidyl ether (B), bisphenol A glycidyl ether, bisphenol F glycidyl ether, bisphenol S glycidyl ether, bisphenol AD glycidyl ether, bisphenol A glycidyl ether and bisphenol can be used. It is preferable to use F-type glycidyl ether.

  As the aromatic glycidyl ether (B), from the viewpoint of further improving the curability of the cationic polymerizable adhesive of the present invention and preventing a decrease in adhesive strength due to heat, light, etc. for a long period of time. It is preferable to use glycidyl ether or bisphenol F-type glycidyl ether, and it is particularly preferable to use bisphenol A diglycidyl ether or bisphenol F diglycidyl ether.

  As the aromatic glycidyl ether (B), it is preferable to use one having two or more glycidyl ether groups in order to give good normal adhesive strength, and it is more preferable to use 2 to 6 ones. preferable.

  The aromatic glycidyl ether (B) can be produced by reacting bisphenol A or bisphenol F with epichlorohydrin or the like. In the obtained aromatic glycidyl ether, it originates from the epichlorohydrin or the like. Some chlorine may remain. In addition, in general, commercially available glycidyl ether group-containing compounds usually contain several percent to several tens percent of chlorine.

  Accordingly, when the aromatic glycidyl ether (B) is produced, it is possible to give a further excellent normal adhesive strength by performing a treatment such as removal of chlorine by rectification or the like, and the discoloration of the polarizer. From the viewpoint of preventing the above. The rectification is preferably performed at a temperature of about 50 to 200 ° C. for about 1 to 200 hours, for example. The amount of chlorine remaining in the aromatic glycidyl ether (B) can be measured based on JISK1200-3-2-200.

  The aromatic glycidyl ether (B) is preferably contained in the total amount of the cationic polymerizable adhesive of the present invention in an amount of 5 to 50% by mass, and in the range of 10 to 40% by mass, excellent normal adhesion. It is more preferable for maintaining the strength for a long period of time.

  In the present invention, in addition to the aromatic glycidyl ether (B), other glycidyl ethers can be used as necessary.

  Examples of the other glycidyl ethers include aliphatic glycidyl compounds (a1) having three glycidyl ether groups such as trimethylolpropane triglycidyl ether, glycerin triglycidyl ether, polyglycerol triglycidyl ether, and diglycerol triglycidyl ether. , Trimethylolpropane diglycidyl ether, 1,6-hexanediol diglycidyl ether, 1,4-butanediol diglycidyl ether, cyclohexanedimethanol diglycidyl ether, propylene glycol diglycidyl ether, diethylene glycol diglycidyl ether, etc. A glycidyl compound having a glycidyl ether group can be used.

  As the other glycidyl ether, hydrogenated bisphenol A-type glycidyl ether, hydrogenated bisphenol F-type glycidyl ether or other aromatic glycidyl ether of the aromatic glycidyl ether (B) may be used. it can.

Next, the cationic polymerization initiator (C) used in the present invention will be described.
The cationic polymerization initiator (C) used in the present invention is, for example, a photo cationic polymerization initiator that generates an acid capable of initiating cationic polymerization by irradiation of energy rays such as ultraviolet rays, or a heat that generates an acid by heating or the like. Cationic polymerization initiator. In particular, when producing a polarizing plate by bonding a polarizer and a protective film, or when producing other optical materials, from the viewpoint of preventing deformation or discoloration of the substrate due to heat, photocationic polymerization starts. It is preferable to use an agent.

As the photocationic polymerization initiator, for example, the cation moiety is aromatic sulfonium, aromatic iodonium, aromatic diazonium, aromatic ammonium, thianthrhenium, thioxanthonium, (2,4-cyclopentadien-1-yl ) [(1-methylethyl) benzene] -Fe cation, and the anion moiety is BF ₄ −, PF ₆ −, SbF ₆ −, [BX ₄ ] ⁻ (where X is at least two fluorine or tri An onium salt composed of a phenyl group substituted with a fluoromethyl group can be used alone or in combination of two or more.

  Examples of the aromatic sulfonium salt include bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (diphenylsulfonio) phenyl] sulfide bishexafluoroantimonate, and bis [4- (diphenyl). Sulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- (diphenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate, diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate, diphenyl-4- (phenylthio) ) Phenylsulfonium hexafluoroantimonate, diphenyl-4- (phenylthio) phenylsulfonium tetrafluoroborate, diphenyl-4- (phenylthio) E) Phenylsulfonium tetrakis (pentafluorophenyl) borate, triphenylsulfonium hexafluorophosphate, triphenylsulfonium hexafluoroantimonate, triphenylsulfonium tetrafluoroborate, triphenylsulfonium tetrakis (pentafluorophenyl) borate, bis [4- ( Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluorophosphate, bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bishexafluoroantimony Bis [4- (di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide bistetrafluoroborate, bis [4- ( Di (4- (2-hydroxyethoxy)) phenylsulfonio) phenyl] sulfide tetrakis (pentafluorophenyl) borate and the like can be used.

  Examples of the aromatic iodonium salt include diphenyliodonium hexafluorophosphate, diphenyliodonium hexafluoroantimonate, diphenyliodonium tetrafluoroborate, diphenyliodonium tetrakis (pentafluorophenyl) borate, bis (dodecylphenyl) iodonium hexafluorophosphate, Bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (dodecylphenyl) iodonium tetrafluoroborate, bis (dodecylphenyl) iodonium tetrakis (pentafluorophenyl) borate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium Hexafluorophosphate, 4-methylphenyl-4- (1-methyl Ethyl) phenyliodonium hexafluoroantimonate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrafluoroborate, 4-methylphenyl-4- (1-methylethyl) phenyliodonium tetrakis (pentafluorophenyl) borate Etc. can be used.

  Examples of the aromatic diazonium salt include phenyldiazonium hexafluorophosphate, phenyldiazonium hexafluoroantimonate, phenyldiazonium tetrafluoroborate, and phenyldiazonium tetrakis (pentafluorophenyl) borate.

  Examples of the aromatic ammonium salt include 1-benzyl-2-cyanopyridinium hexafluorophosphate, 1-benzyl-2-cyanopyridinium hexafluoroantimonate, 1-benzyl-2-cyanopyridinium tetrafluoroborate, 1-benzyl 2-cyanopyridinium tetrakis (pentafluorophenyl) borate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluorophosphate, 1- (naphthylmethyl) -2-cyanopyridinium hexafluoroantimonate, 1- (naphthylmethyl) -2-Cyanopyridinium tetrafluoroborate, 1- (naphthylmethyl) -2-cyanopyridinium tetrakis (pentafluorophenyl) borate, and the like can be used.

  Moreover, S-biphenyl 2-isopropyl thioxanthonium hexafluorophosphate etc. can be used as said thioxanthonium salt.

  The (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe salt includes (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene. ] -Fe (II) hexafluorophosphate, (2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) hexafluoroantimonate, 2,4-cyclopentadiene-1- Yl) [(1-methylethyl) benzene] -Fe (II) tetrafluoroborate, 2,4-cyclopentadien-1-yl) [(1-methylethyl) benzene] -Fe (II) tetrakis (pentafluorophenyl) ) Borate and the like can be used.

Examples of the cationic photopolymerization initiator include CPI-100P, CPI-101A, CPI-200K (manufactured by San Apro Co., Ltd.), Cyracure photocuring initiator UVI-6990, Cyracure photocuring initiator UVI-6922, Syracure photocuring initiator UVI-6976 (manufactured by Dow Chemical Japan Co., Ltd.), Adekaoptomer SP-150, Adekaoptomer SP-152, Adekaoptomer SP-170, Adekaoptomer SP-172, Adeka Optomer SP-300 (above, manufactured by ADEKA Corporation), CI-5102, CI-2855 (above, manufactured by Nippon Soda Co., Ltd.), Sun-Aid SI-60L, Sun-Aid SI-80L, Sun-Aid SI-100L, Sun-Aid SI -110L, Sun-Aid SI-180L, Sun-Aid SI-1 0, Sun-Aid SI-180 (manufactured by Sanshin Chemical Industry Co., Ltd.), Esacure 1064, Esacure 1187 (manufactured by Lamberti), Omnicat 550 (manufactured by IG Resin), Irgacure 250 (Ciba Specialty) -Chemicals Co., Ltd.), Rhodesill Photoinitiator 2074 (RHODORSIL PHOTOINITITOR 2074 (Rhodia Japan Co., Ltd.)), etc. are marketed.
As the thermal cationic polymerization initiator, for example, benzylsulfonium salt, thiophenium salt, thiolanium salt, benzylammonium salt, pyridinium salt, hydrazinium salt, carboxylic acid ester, sulfonic acid ester, amine imide and the like can be used.
Examples of the thermal cationic polymerization initiator include “Adeka Opton CP77”, “Adeka Opton CP66” (manufactured by ADEKA Corporation), “CI-2539”, “CI-2624” (manufactured by Nippon Soda Co., Ltd.), Commercial products such as “Sun-Aid SI-60L”, “Sun-Aid SI-80L”, and “Sun-Aid SI-100L” (manufactured by Sanshin Chemical Industry Co., Ltd.) can also be used.

  The amount of the cationic polymerization initiator (C) used is not particularly limited, but is preferably in the range of 0.1 to 20% by mass, more preferably relative to the total amount of the cationic polymerizable adhesive. The range of 1 to 15% by mass is desirable.

  In addition to the oxetane compound (A), the aromatic glycidyl ether (B), and the cationic polymerization initiator (C), the cation polymerizable adhesive of the present invention may optionally be alicyclic. You may use together an epoxy compound (E), an epoxy-group containing silane compound (F), etc.

The alicyclic epoxy compound (E) is preferably used in the adhesive of the present invention in order to improve the adhesive strength at the initial stage of bonding and prevent the adherend from being displaced.
As said alicyclic epoxy compound (E), what has multiple alicyclic epoxy groups, Preferably 2-4 pieces can be used.

  Among the alicyclic epoxy compounds (E), examples of the alicyclic epoxy compounds having two alicyclic epoxy groups include 3,4-epoxycyclohexenylmethyl-3 represented by the following general formula (7). , 4-Epoxycyclohexanecarboxylate (compound of general formula (7) where a is 0), its caprolactone modified product (compound of general formula (7) where a is 1), its trimethylcaprolactone modified product (structure) The compounds represented by the formula (8) and the structural formula (9)) and their valerolactone-modified products (the structural formula (10) and the structural formula (11)) and the structural formula (12) can be used.

(A in the general formula (7) represents 0 or 1)

Moreover, as an adipic acid ester type alicyclic epoxy compound represented by the general formula (12), for example, Cyracure UVR-6128 (above, manufactured by Dow Chemical Japan Co., Ltd.) and the like are commercially available.
Moreover, as the alicyclic epoxy compound having two alicyclic epoxy groups in the alicyclic epoxy compound (D), a compound represented by the following general formula (13) can also be used.

（一般式（１３）中Ｒ_１〜Ｒ_６は、それぞれ独立して、水素原子または炭素原子数1〜６のアルキル基を示す。）
前記一般式（１３）に示される化合物としては、具体的には、ジシクロヘキシル−３，３’−ジエポキシドを使用することができる。

(In the general formula (13), R _{1 to} R ₆ each independently represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms.)
Specifically, as the compound represented by the general formula (13), dicyclohexyl-3,3′-diepoxide can be used.

  As the alicyclic epoxy compound having three alicyclic epoxy groups, a compound represented by the following general formula (14) can be used.

  In general formula (14), a and b are each independently 0 or 1, and they may be the same or different.

  As the alicyclic epoxy compound represented by the general formula (14), for example, Epolide GT301, Epolide GT302 (manufactured by Daicel Chemical Industries, Ltd.) and the like are commercially available.

  As the alicyclic epoxy compound having four alicyclic epoxy groups, for example, a compound represented by the following general formula (15) can be used.

  In the general formula (15), a to d each independently represent 0 or 1, and they may be the same or different.

  As the alicyclic epoxy compound represented by the general formula (15), for example, Epolide GT401, Epolide GT403 (manufactured by Daicel Chemical Industries, Ltd.) and the like are commercially available.

  The alicyclic epoxy compound (E) is preferably used in the range of 1 to 20% by mass, and preferably in the range of 2 to 10% by mass, based on the total amount of the cationic polymerizable adhesive of the present invention. However, it is preferable for improving the adhesion strength at the initial stage of bonding and preventing the displacement of the adherend.

  In addition, the epoxy group-containing silane compound (F) is preferably used in the adhesive of the present invention because it further increases the normal adhesive strength of the obtained adhesive and can particularly prevent discoloration of the polarizer. When an aminosilane such as 3-aminopropyltriethoxysilane or a vinylsilane such as vinyltriacetoxysilane is used instead of the compound (F), it is polarized as compared with the case where the compound (F) is used. The child discoloration prevention effect tends to be slightly reduced.

  Examples of the epoxy group-containing silane compound (F) include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, and 3-glycidoxypropyl. It is preferable to use methyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane, etc., among which 3-glycidoxypropyltri One selected from the group consisting of ethoxysilane, 3-glycidoxypropyltrimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane More to use With conferring ordinary state adhesive strength superior layer, preferable in preventing the fading or the like of the polarizer.

  As the epoxy group-containing silane compound (F), silicone oils represented by the following general formulas (16) and (17) can also be used.

(In the general formula (16), n represents an integer of 1 or more.)

(R in the general formula (16) represents an organic group, and n represents an integer of 1 or more.)

  The epoxy group-containing silane compound (F) is used in an amount of 0.1 to 1.5% by mass with respect to the total amount of the cationic polymerizable adhesive of the present invention. This is preferable in that it does not cause a decrease and prevents fading of the polarizer.

  In the cationic polymerizable adhesive used in the present invention, the amount of chlorine remaining in the total amount of the cationic polymerizable adhesive is set to 1500 ppm or less to give a further excellent heat-resistant adhesive strength, and a polarizer. From the viewpoint of preventing discoloration and the like, it is very preferable. If the chlorine content exceeds 1500 ppm, the adhesive layer or the resulting polarizer may be discolored or the adhesive strength may be reduced.

  Here, the chlorine referred to in the present invention can be used in combination with chlorine and chloride derived from raw materials such as epichlorohydrin used in the production of the aromatic glycidyl ether (B), and the adhesive of the present invention. It refers to inorganic chlorides such as sodium chloride resulting from various additives.

  By setting the amount of chlorine to 1500 ppm or less, preferably 1000 ppm or less, and more preferably 800 ppm or less, based on the total amount of the cationic polymerizable adhesive, both fading of a polarizer and the like and long-term normal adhesive strength can be achieved. It becomes possible. The amount of chlorine remaining in the total amount of the cationic polymerizable adhesive of the present invention can be measured based on JISK1200-3-2-200.

In particular, in order to further prevent discoloration of the polarizer and the like, it is preferable to use the epoxy group-containing silane compound (E) and to adjust the amount of chlorine remaining in the cationic polymerizable adhesive to 1500 ppm or less. .
As a method for adjusting the amount of chlorine remaining in the cationically polymerizable adhesive of the present invention to 1500 ppm or less, for example, there is a method of removing chlorine by using, for example, rectification or a capturing material capable of capturing chlorine. Can be mentioned. The rectification is preferably performed at a temperature of about 50 to 200 ° C. for about 1 to 200 hours, for example.

  The cationically polymerizable adhesive of the present invention can be produced, for example, by the following method.

  The cationically polymerizable adhesive of the present invention includes, for example, the oxetane compound (A), the aromatic glycidyl ether (B), the cationic polymerization initiator (C), and the like prepared in advance using a closed planetary mixer or the like. If necessary, the oxetane compound (D) having one oxetanyl group, the alicyclic epoxy compound (E), and the epoxy group-containing silane compound (F) can be mixed and stirred. . When the oxetane compound (D) is used, the oxetane compounds (A) and (D) previously mixed may be used.

  The cationically polymerizable adhesive obtained by the above method preferably has a viscosity of 100 mPa · s or less at 25 ° C. from the viewpoint of reducing the thickness of the adhesive layer to be formed as much as possible. This viscosity can be adjusted mainly by using a diluent such as an oxetane compound or an alicyclic epoxy compound, or by using a liquid having a low molecular weight as the aromatic glycidyl ether (B).

  The cationically polymerizable adhesive of the present invention may contain various additives as necessary within a range not impairing the effects of the present invention.

  Examples of the additive include a thixotropic agent, a sensitizer, the various polyols described above and other polyols, a leveling agent, an antioxidant, a tackifier, a wax, a heat stabilizer, a light stabilizer, and a fluorescent enhancement agent. Whitening agent, foaming agent, thermoplastic resin, thermosetting resin, organic solvent, conductivity imparting agent, antistatic agent, moisture permeability improver, water repellent, hollow foam, crystal water-containing compound, flame retardant, water absorbing agent , Hygroscopic agents, deodorants, foam stabilizers, antifoaming agents, antifungal agents, antiseptics, algaeproofing agents, antiblocking agents, hydrolysis inhibitors, organic and inorganic water-soluble compounds, and the like can be used in combination.

  As the thixotropic agent, for example, surface-treated calcium carbonate, fine powder silica, bentonite, zeolite, and the like can be used.

  When using the various additives described above, the additive is, for example, the oxetane compound (A), the aromatic glycidyl ether (B), the cationic polymerization initiator (C) using a closed planetary mixer or the like. And when the said alicyclic epoxy compound (D) and the said epoxy-group containing silane compound (E) are mixed and stirred as needed, it can mix together.

  The cationic polymerizable adhesive of the present invention can be cured by irradiation with energy rays such as ultraviolet rays.

The irradiation of the energy beam such as ultraviolet rays, preferably 50 to 5000 mJ / cm ^2, more preferably 100~3000mJ / cm ^2, particularly preferably it is in the range of 300~1500mJ / cm ^2.

  For example, a known lamp such as a xenon lamp, a xenon-mercury lamp, a metal halide lamp, a high-pressure mercury lamp, or a low-pressure mercury lamp can be used as the ultraviolet ray generation source. In addition, the ultraviolet irradiation amount was based on a value measured in a wavelength region of 300 to 390 nm using a UV checker UVR-N1 (manufactured by Nippon Battery Co., Ltd.).

  Moreover, you may accelerate | stimulate hardening further by heating at about 40-80 degreeC after irradiation of the said energy ray as needed.

Next, the polarizing plate of the present invention will be described.
The polarizing plate of the present invention is obtained by bonding a protective film and a polarizer via an adhesive layer made of the cationic polymerizable adhesive.

  As a protective film that can be used for the production of the polarizing plate, from the viewpoint of improving polarization characteristics, durability, etc., a film or sheet made of a cellulose resin such as triacetyl cellulose, a resin having a cycloolefin structure, a norbornene resin, or the like In particular, it is preferable to use a cellulose-based resin such as triacetyl cellulose.

  Examples of the cellulose resin include cellulose acetate, cellulose acetate propionate, cellulose acetate butyrate, cellulose acetate propionate butyrate, cellulose acetate phthalate, and cellulose nitrate. These can be used alone or 2 More than one species can be used in combination, and among these, it is preferable to use cellulose acetate because a film having excellent mechanical properties and transparency can be obtained.

  In addition, the polarizer is not particularly limited, and various types of polarizers can be used. For example, from a hydrophilic polymer such as polyvinyl alcohol, partially formalized polyvinyl alcohol, ethylene / vinyl acetate copolymer partially saponified product, etc. Using uniaxially drawn dichroic materials such as iodine and dichroic dyes on a plastic base material, polyene-based oriented films such as dehydrated polyvinyl alcohol and dehydrochlorinated polyvinyl chloride can do. Of these, it is preferable to use a polyvinyl alcohol film and a film on which a dichroic substance such as iodine is adsorbed.

  The thickness of the protective film used when producing the polarizing plate of the present invention varies depending on the application used, but is preferably in the range of about 20 μm to 100 μm. Moreover, it is preferable that the thickness of the polarizer is generally in the range of about 5 μm to 50 μm.

  In the polarizing plate of the present invention, the cationic polymerizable adhesive is coated on the protective film, and then the above-mentioned coated surface is irradiated with the above-described amount of ultraviolet light, and then a polarizer is placed on the coated surface. It can be manufactured by bonding. At this time, the thickness of the adhesive layer made of the cationic polymerizable adhesive is preferably as thin as possible for reasons such as impaired optical properties, and specifically, it is preferably 5 μm or less.

  The polarizing plate of the present invention obtained by the above method can be used as a member constituting a display such as a mobile communication terminal such as a mobile phone, a liquid crystal television, a personal computer, and a portable game machine.

  Hereinafter, the present invention will be described more specifically with reference to Examples and Comparative Examples.

[Preparation Example 1]
An isomer mixture (B′-6) of a bisphenol F-type diglycidyl ether compound having a chlorine content of 3.5% obtained according to JIS K1200-3-2-2: under conditions of 1.3 kPa and 185 ° C. Distillation was then carried out under conditions of 0.02 MPa and 70 ° C. to obtain a glycidyl ether group-containing compound (B-1) having a chlorine content of 600 ppm. In addition, as a chlorine content contained in the said glycidyl ether group containing compound (B-1), about 0.05% or more as sodium chloride, the value calculated | required by the Forhardt improved method is 0.05% For those less than the value, the value obtained by ion chromatography analysis was used. Moreover, the chlorine content of the glycidyl ether group-containing compounds (B-2), (B′-3) and (B′-4) described in Preparation Examples 2 to 3 below was also measured by the same method as described above.
[Preparation Example 2]
An isomer mixture of bisphenol A type diglycidyl ether having a chlorine content of 3.5% determined according to JISK1200-3-2 was distilled under conditions of 1.3 kPa and 185 ° C., and then 0.02 MPa and By performing rectification under the condition of 70 ° C., a glycidyl ether group-containing compound (B-2) having a chlorine content of 600 ppm was obtained.

[Preparation Example 3]
Cyclohexane dimethanol diglycidyl ether having a chlorine content of 6.5% determined according to JISK1200-3-2 is distilled under conditions of 1.3 kPa and 185 ° C., and then conditions of 0.02 MPa and 70 ° C. In order to perform rectification sequentially, a glycidyl ether group-containing compound (B′-3) having a chlorine content of 500 ppm, a glycidyl ether group-containing compound (B′-4) having a chlorine content of 1000 ppm, and a chlorine content of 10,000 ppm The glycidyl ether group containing compound (B'-5) was obtained.

[ Reference Example 1]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-4), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) And 4 parts by mass of CPI-100P (a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a photocationic polymerization initiator (C) are mixed and stirred. Thus, a cationically polymerizable adhesive (1) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (1) was determined according to the method described later, it was 247 ppm.

[ Reference Example 2]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) And 4 parts by mass of CPI-100P (a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a photocationic polymerization initiator (C) are mixed and stirred. Thus, a cationically polymerizable adhesive (2) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (2) was determined according to the method described later, it was 219 ppm.

[ Reference Example 3]
In a closed planetary mixer, 20.0 parts by mass of a glycidyl ether group-containing compound (B-2) and 20.0 parts by mass of a glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) And 4 parts by mass of CPI-100P (a diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a cationic photopolymerization initiator (C) and stirring. A cationically polymerizable adhesive (3) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (3) was determined according to the method described later, it was 211 ppm.

[ Reference Example 4]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) , 0.5 parts by mass of KBE-403 (3-glycidoxypropyltriethoxysilane manufactured by Shin-Etsu Chemical Co., Ltd.) as the epoxy group-containing silane compound (F), and CPI-100P as the photocationic polymerization initiator (C) (San Apro Co., Ltd. diphenyl-4- (phenylthio) phenylsulfonium hexafluoroph A cationically polymerizable adhesive (4) was prepared by mixing and stirring 4 parts by mass of a propylene carbonate 50 mass% solution of phosphate. It was 218 ppm when the chlorine content contained in the whole quantity of the obtained cationic polymerizable adhesive (4) was determined according to the method described later.

[Example 1 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 25.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 30.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) , Selecoxide 2021P (3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate manufactured by Daicel Chemical Industries) as an alicyclic epoxy compound (E), and a photocation As a polymerization initiator (C), CPI-100P (diphenyl-4- (San Apro Co., Ltd.) Eniruchio) propylene carbonate 50 wt% solution of triphenylsulfonium hexafluoro off phosphate) mixing 4 parts by mass, by stirring, cationically polymerizable adhesive (5) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (5) was determined according to the method described later, it was 209 ppm.

[ Reference Example 5 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 45.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron oxetane OXT-211 (3-ethyl-3- (phenoxymethyl) oxetane manufactured by Toa Gosei Co., Ltd.) 15.0 4 parts by mass of CPI-100P (a diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate phosphate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) is mixed and stirred as a mass part and a cationic photopolymerization initiator (C). Thus, a cationically polymerizable adhesive (6) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (6) was determined according to the method described later, it was 212 ppm.

[ Reference Example 6 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron Oxetane OXT-211 (3-ethyl-3- (phenoxymethyl) oxetane manufactured by Toa Gosei Co., Ltd.) 25.0 4 parts by mass of CPI-100P (a diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate phosphate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a cationic photopolymerization initiator (C) is mixed and stirred. By doing so, a cationically polymerizable adhesive (7) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (7) was determined according to the method described later, it was 214 ppm.

[ Reference Example 7 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron oxetane OXT-212 (3-ethyl-3- (2-ethylhexyloxymethyl) oxetane manufactured by Toagosei Co., Ltd.) ) 25.0 parts by mass, and 4 parts by mass of CPI-100P (a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a photocationic polymerization initiator (C) The cation polymerizable adhesive (8) is prepared by mixing and stirring. Made. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (8) was determined according to the method described later, it was 208 ppm.

[ Reference Example 8 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 25.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron oxetane OXT-213 (3-ethyl-3- (cyclohexyloxy) methyl oxetane manufactured by Toagosei Co., Ltd.) 0 parts by mass, and 4 parts by mass of CPI-100P (a propylene carbonate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a photocationic polymerization initiator (C), A cationically polymerizable adhesive (9) was prepared by stirring. It was. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (9) was determined according to the method described later, it was 215 ppm.

[Example 2 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 25.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron oxetane OXT-211 (3-ethyl-3- (phenoxymethyl) oxetane manufactured by Toa Gosei Co., Ltd.) 30.0 Part by mass, as alicyclic epoxy compound (E), Celoxide 2021P (3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate manufactured by Daicel Chemical Industries, Ltd.) 5.0 parts by mass, epoxy KBE-403 (3-glycidoxy manufactured by Shin-Etsu Chemical Co., Ltd.) as the group-containing silane compound (E) 0.5 parts by mass of propyltriethoxysilane) and 50% by mass of propylene carbonate of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate as CPI-100P (San Apro Co., Ltd.) as the cationic photopolymerization initiator (C) Solution) A cationically polymerizable adhesive (10) was prepared by mixing and stirring 4 parts by mass. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (10) was determined according to the method described later, it was 216 ppm.

[Example 3 ]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and Aron Oxetane OXT-211 (3-ethyl-3- (phenoxymethyl) oxetane manufactured by Toa Gosei Co., Ltd.) 25.0 Part by mass, as alicyclic epoxy compound (E), Celoxide 2021P (3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexene carboxylate manufactured by Daicel Chemical Industries, Ltd.) 5.0 parts by mass, epoxy KBE-403 (3-glycidoxy manufactured by Shin-Etsu Chemical Co., Ltd.) as the group-containing silane compound (F) 0.5 parts by mass of propyltriethoxysilane) and 50% by mass of propylene carbonate of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate as CPI-100P (San Apro Co., Ltd.) as the cationic photopolymerization initiator (C) Solution) A cationically polymerizable adhesive (11) was prepared by mixing and stirring 4 parts by mass. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (11) was determined according to the method described later, it was 216 ppm.

[Comparative Example 1]
In a closed planetary mixer, 40.0 parts by mass of a glycidyl ether group-containing compound (B′-3), Aron Oxetane OXT-221 (bis [1-ethyl (3-oxetanyl)] methyl ether manufactured by Toa Gosei Co., Ltd. ) 35.0 parts by mass and 25.0 parts by mass of Aron Oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) and CPI-100P (Sanpro) as the photocationic polymerization initiator (C) A cationically polymerizable adhesive (1 ′) was prepared by mixing and stirring 4 parts by mass of propylene carbonate (50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate) manufactured by Co., Ltd. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (1 ′) was determined according to the method described later, it was 194 ppm.

[Comparative Example 2]
In a closed planetary mixer, 40.0 parts by mass of a glycidyl ether group-containing compound (B′-4), Aron oxetane OXT-221 (bis [1-ethyl (3-oxetanyl)] methyl ether manufactured by Toa Gosei Co., Ltd. ) 35.0 parts by mass and 25.0 parts by mass of Aron Oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) and CPI-100P (Sanpro) as the photocationic polymerization initiator (C) A cationically polymerizable adhesive (2 ′) was prepared by mixing and stirring 4 parts by mass of a propylene carbonate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorosulfate manufactured by Co., Ltd. It was 383 ppm when the chlorine content contained in the whole quantity of the obtained cationic polymerizable adhesive (2 ') was calculated | required according to the method mentioned later.

[Comparative Example 3]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B′-3) and 20.0 parts by mass of the glycidyl ether group-containing compound (B-1), Aron Oxetane OXT-191 (Toa Gosei Co., Ltd.) 35.0 parts by mass of oxetanyl silicate manufactured by company) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) and photocationic polymerization initiator (C) CPI-100P (a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) 4 parts by mixing and stirring, cationically polymerizable adhesive (3 ′) Was prepared. It was 211 ppm when the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (3 ′) was determined according to the method described later.

[Comparative Example 4]
In a closed planetary mixer, 20.0 parts by mass of a glycidyl ether group-containing compound (B′-3) and 20.0 parts by mass of a glycidyl ether group-containing compound (B-2), Aron Oxetane OXT-191 (Toa Gosei Co., Ltd.) Oxetanyl silicate manufactured by company) 35.0 parts by mass, Aron Oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) 25.0 parts by mass, and photocationic polymerization initiator (C) CPI-100P (a propylene carbonate 50 mass% solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) 4 parts by mixing and stirring, cationically polymerizable adhesive (4 ′) Was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (4 ′) was determined according to the method described later, it was 213 ppm.

[Comparative Example 5]
In a closed planetary mixer, 20.0 parts by mass of the glycidyl ether group-containing compound (B-1) and 20.0 parts by mass of the glycidyl ether group-containing compound (B′-5), Aron Oxetane OXT-221 (Toa Gosei Co., Ltd.) 35.0 parts by mass of bis [1-ethyl (3-oxetanyl)] methyl ether) and 25.0 parts by mass of Aron oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) And 4 parts by mass of CPI-100P (a diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate 50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate manufactured by San Apro Co., Ltd.) as a cationic photopolymerization initiator (C) and stirring. A cationically polymerizable adhesive (5 ′) was prepared. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (5 ′) was determined according to the method described later, it was 2019 ppm.

[Comparative Example 6]
In a closed planetary mixer, 40.0 parts by mass of a glycidyl ether group-containing compound (B′-6), Aron oxetane OXT-221 (bis [1-ethyl (3-oxetanyl)] methyl ether manufactured by Toa Gosei Co., Ltd. ) 35.0 parts by mass and 25.0 parts by mass of Aron Oxetane OXT-101 (3-hydroxymethyl-3-ethyloxetane manufactured by Toa Gosei Co., Ltd.) and CPI-100P (Sanpro) as the photocationic polymerization initiator (C) A cationically polymerizable adhesive (6 ′) was prepared by mixing and stirring 4 parts by mass of propylene carbonate (50% by mass solution of diphenyl-4- (phenylthio) phenylsulfonium hexafluorophosphate) manufactured by Co., Ltd. When the chlorine content contained in the total amount of the obtained cationic polymerizable adhesive (6 ′) was determined according to the method described later, it was 13462 ppm.

[Measurement method of total chlorine content]
The chlorine content contained in the cationic polymerizable adhesive of the present invention was measured based on JIS K 1200-3-2-200. Specifically, for an adhesive whose amount of chlorine in the present invention is 0.05% or more as sodium chloride, the value obtained by the Forhardt modification method is taken as the chlorine content of the adhesive, 0.05% For adhesives that are less than 1, the value obtained by ion chromatography analysis was used as the chlorine content of the adhesive.
[Production method of polarizer]
Kuraraypoval PVA-117H (polyvinyl alcohol manufactured by Kuraray Co., Ltd., degree of polymerization 1700, completely saponified product, powder) dissolved in water with a polyvinyl alcohol aqueous solution (non-volatile content 8% by mass), a bar coater It was applied onto a release film, dried for 5 minutes in an environment at 80 ° C., and then the release film was removed to prepare a polyvinyl alcohol film having a thickness of 75 μm.
Next, the obtained polyvinyl alcohol film was fixed to a stretching machine, and the film was stretched in hot water at 40 ° C. until it became three times larger in a uniaxial direction.
After removing water adhering to the surface of the stretched film obtained above, the stretched film was adjusted to 30 ° C. containing 0.02 parts by mass of iodine, 2 parts by mass of potassium iodide and 100 parts by mass of water. It was immersed in the aqueous solution.
Next, the stretched film was immersed in an aqueous solution adjusted to 56.5 ° C. containing 12 parts by mass of potassium iodide, 5 parts by mass of boric acid, and 100 parts by mass of water.
After the immersed stretched film is washed in pure water adjusted to 8 ° C. and dried in an environment of 65 ° C., a polarizer in which iodine is adsorbed and oriented on the surface of the stretched film made of polyvinyl alcohol (polarized light) Film).

[Production Method of Polarizing Plate]
On one surface of two corona-treated triacetylcellulose films (thickness 80 μm, length 297 mm, width 210 mm), the cationic polymerizable adhesives obtained in Examples and Comparative Examples using an applicator are about 2 μm thick. Each of the coated surfaces was applied with UV light of 30 to 100 mJ / cm ² using a conveyor type UV irradiation device CSOT-40 (high pressure mercury lamp manufactured by Nippon Battery Co., Ltd., strength 120 W / cm).

  Next, the polarizer obtained by the above method (thickness of 42 μm, length of 297 mm, width of 210 mm is bonded to each of the two triacetyl cellulose films, and they are pressed using a rubber roller and bonded to each other. A polarizing plate was produced by heating for 1 minute in a dryer at ° C.

[Evaluation method for normal adhesive strength]
After leaving the polarizing plate obtained by the above method in a dryer set at 85 ° C. for 1500 hours, using a tensile tester (manufactured by Imada Manufacturing Co., Ltd., tensile speed = 50 mm / min T-type peeling), The peel strength at the interface between triacetyl cellulose and polyvinyl alcohol constituting each polarizing plate was measured. A film having a peel strength of 10 N / 25 mm or more or a triacetylcellulose film breakage (MB) was evaluated as “good” and a film having a peel strength of less than 10 N / 25 mm was evaluated as “bad”.

[Evaluation of change in transmittance and fading of polarizer]
The degree of fading and discoloration of the polarizer due to the influence of the cationic polymerizable adhesive is determined by the transmittance of the polarizing plate before and after the polarizing plate produced by the above method was allowed to stand for 1500 hours at a temperature of 65 ° C. and a humidity of 90%. Evaluation was based on the rate of change.
The transmittance of the polarizing plate was measured using a visible spectrophotometer (JASCO V-570 manufactured by JASCO Corporation, measurement wavelength 200 to 900 nm, scanning speed 400 nm / min). When the transmittance (%) of the polarizing plate after being left is changed by ± 5% or more with respect to the transmittance (%) of the polarizing plate before being left, it was evaluated as “x”, and the polarizing plate after being left as it was A sample having a change in transmittance of less than ± 5% was evaluated as “◯”.

Claims (13)

An adhesive comprising an oxetane compound (A) having a molecular weight of 100 to 800 having two or more oxetanyl groups, an aromatic glycidyl ether (B), and a cationic polymerization initiator (C), wherein the adhesive is Furthermore, the oxetane compound (D) which has one oxetanyl group and the alicyclic epoxy compound (E) which has a structure shown by following General formula (7) are contained, Use of the said oxetane compounds (A) and (D) The amount is in the range of 20 to 70% by mass with respect to the total amount of the cationic polymerizable adhesive, and the amount of the aromatic glycidyl ether (B) used is 5 to 50% by mass in the total amount of the cationic polymerizable adhesive. There, the amount of the cationic polymerization initiator (C) is in the range of 0.1 to 20 wt% based on the total amount of cationically polymerizable adhesives, residual chlorine in the total amount of the adhesive 1500 Cationic polymerizable adhesive, characterized in that it pm or less.

(A in the general formula (7) represents 0 or 1) The cationically polymerizable adhesive according to claim 1, wherein the oxetane compound (A) is bis [1-ethyl (3-oxetanyl)] methyl ether. The cationically polymerizable adhesive according to claim 1, wherein the aromatic glycidyl ether (B) is at least one selected from the group consisting of bisphenol A diglycidyl ether and bisphenol F diglycidyl ether. Before SL oxetane compound wherein the oxetanyl group oxetane compound having a (A) equivalent ratio of the oxetanyl group of the (D) [oxetanyl group of the oxetanyl group / (D) having a (A)] is 0.1 to 35. The cationically polymerizable adhesive according to claim 1, which is zero. The cationically polymerizable adhesive according to claim 4, wherein the oxetane compound (D) has a molecular weight of 100 to 500. The oxetane compound (D) is 3-hydroxymethyl-3-ethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and 3-ethyl-3. The cationically polymerizable adhesive according to claim 4, which is at least one selected from the group consisting of-(cyclohexyloxy) methyloxetane. Bis [1-ethyl (3-oxetanyl)] methyl ether as the oxetane compound (A) is contained in an amount of 20 to 70% by mass based on the whole of the cationic polymerizable adhesive, and the oxetane compound (D). 3-hydroxymethyl-3-ethyloxetane, 3-ethyl-3- (phenoxymethyl) oxetane, 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane and 3-ethyl-3- (cyclohexyloxy) as The cationically polymerizable adhesive according to claim 4, wherein 20 to 70% by mass of one or more selected from the group consisting of methyl oxetane is contained. The cationically polymerizable adhesive according to claim 1 , wherein the alicyclic epoxy compound (E) is 3,4-epoxycyclohexenylmethyl-3 ′, 4′-epoxycyclohexenecarboxylate. The cationically polymerizable adhesive according to claim 1 , further comprising an epoxy group-containing silane compound (F). The cationically polymerizable adhesive according to claim 9 , wherein the epoxy group-containing silane compound (F) is contained in an amount of 0.1 to 1.5% by mass with respect to the total amount of the cationically polymerizable adhesive. The epoxy group-containing silane compound (F) is 3-glycidoxypropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldiethoxysilane, 3-glycidoxypropylmethyldimethoxysilane. The cationic polymerization property according to claim 9 , which is at least one selected from the group consisting of 2- (3,4-epoxycyclohexyl) ethyltriethoxysilane and 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane. adhesive. The cationically polymerizable adhesive according to any one of claims 1 to 11 , which is used for adhesion between a polarizer constituting a polarizing plate and a protective film. A protective film made of triacetyl cellulose or a protective film made of cycloolefin and a polarizer made of polyvinyl alcohol are bonded via a cationic polymerizable adhesive, and the cationic polymerizable adhesive is claimed. a polarizing plate characterized in that it is a cationically polymerizable adhesive according to claim 1 2.