KR20100100695A - Photocurable adhesive composition, polarizing plate and a process for producing the same, optical member and liquid crystal display device - Google Patents

Abstract

PURPOSE: A photo-curable adhesive composition, a polarizer and a manufacturing method thereof, an optical member, and a liquid crystal display are provided to easily cure the composition using the irradiation of active energy rays and ultraviolet rays, and to firmly attach a polarized light device. CONSTITUTION: A photo-curable adhesive composition is used for attaching a protective film formed with a transparent resin film formed with a compound selected from the group consisting of a polyester resin, a polycarbonate resin, and an acrylic resin, to a polarizer formed with a polyvinylalcohol-based resin film.

Description

PHOTOCURABLE ADHESIVE COMPOSITION, POLARIZING PLATE AND A PROCESS FOR PRODUCING THE SAME, OPTICAL MEMBER AND LIQUID CRYSTAL DISPLAY DEVICE}

This invention relates to the photocurable adhesive composition used for bonding a polarizer and a protective film in a polarizing plate, the polarizing plate which bonded the protective film to the polarizer using this adhesive composition, and the manufacturing method of this polarizing plate. This invention also relates to the optical member and liquid crystal display device which used this polarizing plate.

A polarizing plate is useful as one of the optical components which comprise a liquid crystal display device. The polarizing plate is inserted into a liquid crystal display device in the state which laminated | stacked the protective film on both surfaces of the polarizer normally, and is used. It is also known to provide a protective film only on one side of the polarizer. In most cases, a layer having a separate optical function is bonded to the other side as a protective film instead of a simple protective film. Moreover, as a manufacturing method of a polarizer, the method of boric-acid-processing 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 a 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 up, problems such as cracking in the processing direction occur. Accordingly, the polarizer after drying is conventionally immediately coated with an aqueous adhesive, and then a protective film is bonded at the same time through this adhesive. Conventionally, as a protective film, the triacetyl cellulose film of thickness 30-120 micrometers is used.

In many cases, a polyvinyl alcohol adhesive is used for adhesion between the polarizer and the protective film, particularly a protective film made of a triacetyl cellulose film. Alternatively, an urethane adhesive may be used instead. For example, Japanese Patent Application Laid-Open No. 7-120617 (Patent Document 1) uses a urethane prepolymer as an adhesive, and bonds a polarizer having a high water content to a cellulose acetate protective film such as a triacetyl cellulose film. Is described.

On the other hand, since triacetyl cellulose has high moisture permeability, polarizing plates bonded to both surfaces using this resin film as a protective film have problems such as deterioration under moist heat, for example, under conditions such as a temperature of 70 ° C. and a relative humidity of 90%. there was. Therefore, the method of solving such a problem is also proposed by making a resin film which has a water vapor transmission rate lower than a triacetyl cellulose film as a protective film, For example, it is known to use amorphous polyolefin resin as a protective film. Specifically, laminating a thermoplastic saturated norbornene-based resin sheet on at least one surface of the polarizer as a protective film is described in JP-A-6-51117 (Patent Document 2).

When joining such a protective film with low moisture permeability with a conventional apparatus, after bonding a protective film to the polyvinyl alcohol-type polarizer using the adhesive which uses water as a main solvent, for example, the polyvinyl alcohol aqueous solution, the solvent is dried. In so-called wet lamination, sufficient adhesive strength cannot be obtained or the appearance may be poor. This is due to the fact that a film having a low water vapor transmission rate is generally more hydrophobic than a triacetyl cellulose film, and that water which is a solvent cannot be sufficiently dried because the water vapor transmission rate is lower.

Therefore, Japanese Unexamined Patent Application Publication No. 2000-321432 (Patent Document 3) proposes bonding a polyvinyl alcohol polarizer and a protective film made of thermoplastic saturated norbornene resin with a polyurethane adhesive. However, the polyurethane-based adhesive has a problem that it takes a long time to cure, and the adhesive force is not necessarily sufficient.

On the other hand, it is also known to bond different kinds of protective films to both surfaces of the polarizer. For example, Japanese Patent Application Laid-Open No. 2002-174729 (Patent Document 4) discloses an amorphous property on one surface of a polarizer made of a polyvinyl alcohol-based resin film. It is proposed to bond a protective film made of a polyolefin resin, and to join the protective film made of a resin different from the amorphous polyolefin resin, for example, triacetyl cellulose, to the other side thereof, and JP 2005-208456 A In the publication (Patent Document 5), a cycloolefin resin film is laminated on one side of a polarizing film made of polyvinyl alcohol-based resin via an aqueous first adhesive containing a urethane resin, and on the other side, a first adhesive Cellulose acetate through an aqueous solution of a second adhesive other than, for example, polyvinyl alcohol-based resin To an agarose-based resin laminated film has been proposed.

What is called an amorphous polyolefin resin in the said patent document 4, and a cycloolefin resin in the said patent document 5 consists of a polycyclic cycloolefin like norbornene, its derivatives, and dimethanooctahydronaphthalene When it has a unit of a monomer and a double bond remains like a ring-opening polymer, it is preferably the thermoplastic resin hydrogenated therein.

In addition, Japanese Patent Laid-Open No. 2004-245925 (Patent Document 6) discloses an adhesive mainly containing an epoxy resin containing no aromatic ring, and irradiating active energy rays to the adhesive to cationic polymerization to form a polarizer. A method of adhering a protective film is proposed. The epoxy adhesive disclosed herein is particularly effective for bonding various transparent resin films, including amorphous polyolefin resins and cellulose resins, to polarizers, and in particular, when the acrylic resin is a protective film, the adhesive force is not necessarily sufficient. Has been evident.

Japanese Patent Publication No. 7-120617 Japanese Patent Laid-Open No. 6-51117 Japanese Patent Laid-Open No. 2000-321432 Japanese Patent Laid-Open No. 2002-174729 Japanese Patent Laid-Open No. 2005-208456 Japanese Patent Laid-Open No. 2004-245925

In order to solve the problem of joining a polyvinyl alcohol polarizer with a low moisture-permeable protective film by wet lamination, it is thought to increase the length by drying after bonding and to obtain drying time. There arises a problem that discoloration due to thermal degradation is likely to occur. Therefore, it is conceivable to lower the drying temperature so as not to cause thermal deterioration of the polarizer. In this case, in order to sufficiently dry, it is necessary to further lengthen the drying furnace, and there is a problem that equipment investment is enormous. In the case where different types of protective films are bonded to both surfaces of the polarizer, the shrinkage ratios due to the heat of these protective films are different. There is a problem that curling is likely to occur.

In order to improve such a problem, it is conceivable to employ a joining method by dry lamination. However, since the adhesive having dry lamination aptitude is very high in viscosity, due to the problem that the physical strength of the polarizer is weak, the method of bonding the polarizer and the protective film is limited to the method of coating the adhesive on the protective film and then bonding the polarizer. . In this method, when a foreign material adheres to the coating surface of an adhesive agent before joining, a foreign material cannot be concealed, and since a bubble generate | occur | produces between an adhesive layer and a polarizer after a foreign material as a starting point, it becomes a cause of a bright spot defect.

MEANS TO SOLVE THE PROBLEM The present inventors earnestly researched in order to develop the photocurable adhesive agent which expresses favorable adhesiveness in a short time, when making the protective film of a polarizer the resin film with low moisture permeability selected from polyester resin, a polycarbonate resin, and an acrylic resin. It has been found that by using a specific photocurable adhesive, these protective films can be bonded in a short time. The adhesive also found that even when the acrylic resin film was used as a protective film, it provided high adhesion between the polarizer and the same, even when the polyester resin film or polycarbonate resin film was used as a protective film.

Therefore, an object of the present invention can be adhered to the polarizer with sufficient adhesive strength in a short time even when the resin film having a low water vapor transmission rate selected from polyester resins, polycarbonate resins and acrylic resins is used as a protective film. It is providing the photocurable adhesive which does not cause, and providing the polarizing plate by which the protective film was bonded to the polarizer using the adhesive. Another object of the present invention is to provide an optical member capable of forming a liquid crystal display device having excellent reliability using this polarizing plate, and to apply the same to a liquid crystal display device.

That is, the protective film which consists of a transparent resin film chosen from the group which consists of a polyester resin, a polycarbonate resin, and an acrylic resin to the polarizer which consists of a polyvinyl alcohol-type resin film uniaxially stretched and the dichromatic pigment adsorption-oriented according to this invention. An adhesive composition for adhering a polymer comprising: (A) an epoxy compound having at least two epoxy groups in a molecule, (B) an oxetane compound having at least one oxetanyl group in a molecule, and (C) a photo cationic polymerization initiator And the weight ratio (A) / (B) of the epoxy compound (A) and the oxetane compound (B) is about 90/10 to 10/90, and the amount of the photocationic polymerization initiator (C) is about 0.5 in the composition. To 20% by weight of the photocurable adhesive composition is provided.

In the photocurable adhesive composition, the epoxy compound (A) contains a compound having at least two epoxy groups and at least one aromatic ring in a molecule, specifically, at least two epoxy groups and at least one aromatic ring in a molecule A compound having a compound or a compound having at least two epoxy groups in the molecule and at least one aromatic ring and a compound having at least two epoxy groups in the molecule and having no aromatic ring are preferable. In addition, this epoxy compound (A) contains one or more selected from the group consisting of glycidyl ether and glycidyl ester of an aromatic compound, specifically, glycidyl ether and glycidyl ester of an aromatic compound. A mixture of one or more selected from the group consisting of one or more selected from the group consisting of glycidyl ether compounds and glycidyl ester compounds of aromatic compounds and epoxy compounds (A) other than them is more preferable.

On the other hand, examples of the oxetane compound (B) include a compound having one oxetanyl group and at least one aromatic ring in a molecule, a compound having one oxetanyl group and at least one aromatic ring in a molecule and at least one jade in the molecule. A mixture with a compound having a cetanyl group and no aromatic ring, a compound having two oxetanyl groups in a molecule, a compound having at least two oxetanyl groups in a molecule, a compound having two oxetanyl groups in a molecule and a molecule A mixture with a compound having one oxetanyl group, a mixture of a compound having at least two oxetanyl groups in a molecule and a compound having one oxetanyl group in a molecule, and the like are preferable.

These photocurable adhesive compositions may further contain an unsaturated compound having at least one ethylenically unsaturated bond in the molecule as the component (D), in which case the amount of the unsaturated compound (D) is generally 35% by weight or less in the composition. It is the ratio of about 5-25 weight% is preferable. It is preferable that this unsaturated compound (D) is a (meth) acrylic-type compound which has at least 1 (meth) acryloyl group and at least 1 alicyclic skeleton or an aromatic ring skeleton in a molecule | numerator, Furthermore, it is di which has a tricyclodecane skeleton. It is more preferable that it is (meth) acrylate.

When an adhesive composition contains the said unsaturated compound (D) and especially a (meth) acrylic-type compound, it is preferable to contain a radical photopolymerization initiator as (E) component. The amount of the radical photopolymerization initiator (E) is preferably in a proportion of about 10% by weight or less in the composition.

In addition, these photocurable adhesive compositions can contain the other component which does not have polymerizability as (F) component, and in that case, the ratio of the other component (F) is usually preferably about 10% by weight or less in the composition.

Furthermore, according to the present invention, a transparent resin film selected from the group consisting of polyester resins, polycarbonate resins, and acrylic resins through an adhesive is applied to a polarizer made of a polyvinyl alcohol-based resin film uniaxially stretched and adsorbed and oriented by a dichroic dye. The polarizing plate by which the protective film which consists of these is joined is provided, The polarizing plate in which the adhesive agent is formed from the photocurable adhesive composition in any one of the above is provided.

This polarizing plate comprises the adhesive agent application process which apply | coats the photocurable adhesive composition of any one of the above to at least one of the bonding surfaces of a polarizer and a protective film, the bonding process which bonds a polarizer and a protective film through the adhesive layer obtained, and the adhesive bond layer It can manufacture by the method containing the hardening process of hardening | curing a photocurable adhesive composition in the state by which the polarizer and the protective film were bonded through. Specifically, after the uncured photocurable adhesive composition is coated on the polarizer, a protective film is bonded to the adhesive composition coating surface, and then the adhesive composition is cured to form an adhesive layer. After coating a photocurable adhesive composition, the method of bonding a polarizer to the adhesive composition coating surface, and then hardening | curing the adhesive composition to form an adhesive layer, and flexible the said uncured photocurable adhesive composition between a polarizer and a protective film, After pressing and bonding the adhesive composition of a polarizer and a protective film between rolls etc. uniformly and spreading | extending it, the method etc. which harden | cure the adhesive composition and form an adhesive bond layer can be employ | adopted.

Moreover, according to this invention, the optical member by which the optical layer which shows an optical function different from the said polarizing plate is laminated is provided. It is preferable that the other optical layer in this case contains a retardation plate. There is also provided a liquid crystal display device in which the optical member is disposed on one or both sides of the liquid crystal cell.

The photocurable adhesive composition of this invention can harden | cure easily by irradiation of active energy rays, such as an ultraviolet-ray, and has the feature that a polarizer and a protective film can be firmly adhere | attached in a short time. This adhesive composition is particularly useful when the protective film is made of an acrylic resin. Since the adhesive composition hardens in a short time, the polarizing plate obtained by bonding a polarizer and a protective film through this adhesive composition can be manufactured efficiently. Moreover, the optical member which combined this polarizing plate with another optical layer can form the liquid crystal display device which was excellent in reliability.

Hereinafter, the present invention will be described in detail. In the present invention, a photocurable adhesive composition having a specific composition is used to bond a protective film made of a transparent resin film to a polarizer made of a polyvinyl alcohol-based resin film uniaxially stretched and adsorbed or oriented by a dichroic dye. In this way, a polarizing plate is obtained by bonding a polarizer and a protective film through a photocurable adhesive composition. This polarizing plate can be laminated | stacked with the optical layer which has another optical function, and can be set as an optical member. Moreover, this optical member can be arrange | positioned at least one side of a liquid crystal cell, and can be set as a liquid crystal display device. Hereinafter, description advances in order of the photocurable adhesive composition, a polarizing plate, the manufacturing method of a polarizing plate, an optical member, and a liquid crystal display device.

[Photocurable Adhesive Composition]

In this invention, the photocurable adhesive composition of a specific composition is used for bonding a polarizer and a protective film. Hereinafter, this photocurable adhesive composition may only be called "photocurable adhesive agent." The photocurable adhesive agent of this invention contains three components of the following (A), (B), and (C) as essential.

(A) an epoxy compound having at least two epoxy groups in a molecule,

(B) an oxetane compound having at least one oxetanyl group in the molecule, and

(C) Photo cationic polymerization initiator.

In this specification, the epoxy compound of said (A) is also simply called "(A) component" or "epoxy compound (A)." Similarly, in this specification, the oxetane compound of (B) is also called "(B) component" or "oxetane compound (B)", and the photocationic polymerization initiator of (C) is called "(C) component" or "photocationic Polymerization initiator (C) ”.

The epoxy compound of component (A) and the oxetane compound of component (B) are preferably such that the weight ratio of (A) / (B) is about 90/10 to about 10/90. Moreover, it is preferable to make the radical photopolymerization initiator of (C) component become the ratio of about 0.5 to 20 weight% in a composition.

This photocurable adhesive agent can optionally contain the unsaturated compound which has at least 1 ethylenically unsaturated bond in a molecule | numerator as (D) component, and when it contains such an unsaturated compound (D), it is a radical photopolymerization initiator as (E) component. It is preferable to contain. In addition, this photocurable adhesive agent may contain the other component which does not have polymerizability as (F) component.

In the present specification, the unsaturated compound of the above (D) is also simply referred to as "(D) component" or "unsaturated compound (D)". Similarly, in this specification, the radical photopolymerization initiator of (E) is also called "(E) component" or "radical radical polymerization initiator (E)", and the other component which does not have the polymerizability of (F) is "(F) component Or "other components (F) having no polymerization property".

<Epoxy Compound (A)>

In the photocurable adhesive agent of this invention, if the epoxy compound used as (A) component has at least two epoxy groups in a molecule | numerator, it will not specifically limit, Various curable epoxy compounds generally known can be used. As a preferable epoxy compound used as (A) component, it has a compound which has at least 2 epoxy groups and at least 1 aromatic ring in a molecule | numerator (henceforth "an aromatic epoxy compound"), or has at least 2 epoxy groups in a molecule | numerator, At least one of them is exemplified by a compound (hereinafter referred to as an "alicyclic epoxy compound") formed between two adjacent carbon atoms constituting an alicyclic ring.

The aromatic epoxy compound is not particularly limited as long as it does not interfere with the effects of the present invention, but is not limited to bisphenols such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol A. Type epoxy resins; Novolac type epoxy resins such as phenol novolac type epoxy resins, and cresol novolac type epoxy resins; Others, biphenyl type epoxy resin, hydroquinone diglycidyl ether, resorcin diglycidyl ether, terephthalic acid diglycidyl ester, phthalic acid diglycidyl ester, epoxide of styrene-butadiene copolymer, styrene-isoprene air Examples of the epoxide of the copolymer, the addition reactant of the terminal carboxylic acid polybutadiene and the bisphenol A epoxy resin, and the like can be given.

Here, an epoxy resin means the compound or polymer which has an average of 2 or more epoxy groups in a molecule | numerator, and hardens | cures by reaction. According to the practice in this field, in the present specification, even if a monomer has two or more curable epoxy groups in a molecule, it may be called an epoxy resin even if it is a monomer.

The alicyclic epoxy compound is not particularly limited as long as it does not interfere with the effects of the present invention, but dicyclopentadiene dioxide, limonene dioxide, 4-vinylcyclohexene dioxide, 3,4-epoxycyclohexylmethyl 3,4- Examples thereof include an epoxycyclohexanecarboxylate and a compound having at least one epoxidized cyclohexyl group such as bis (3,4-epoxycyclohexylmethyl) adipate.

Aliphatic epoxy compounds such as 1,6-hexanediol diglycidyl ether, trimethylolpropanetriglycidyl ether, pentaerythritol tetraglycidyl ether, and polytetramethylene glycol diglycidyl ether; Epoxy compounds in which an aromatic ring such as diglycidyl ether of hydrogenated bisphenol A is hydrogenated; Compounds in which both ends of the polybutadiene of both terminal hydroxyl groups are glycidyl ethers, internal epoxides of polybutadiene, and compounds in which the double bonds of the styrene-butadiene copolymer are partially epoxidized [for example, Daicel Chemical Industries, Ltd. ( Note) " epoprene " " and isoprene units of block copolymers of ethylene-butylene copolymer and polyisoprene are partially epoxidized compounds (for example, " L-207 &quot; A polymer epoxy compound etc. can also be an epoxy compound of (A) component.

Among these, the aromatic epoxy compound is preferable because it is excellent in durability and the like when the polarizing plate is used, and particularly excellent in adhesion to the polarizer and the protective film. Moreover, as this aromatic epoxy compound, glycidyl ether of an aromatic compound, glycidyl ester of an aromatic compound, etc. are mentioned as a preferable example. Specific examples of glycidyl ethers of aromatic compounds include bisphenol type epoxy resins such as diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and diglycidyl ether of bisphenol A; Novolac type epoxy resins such as phenol novolac type epoxy resins and cresol novolac type epoxy resins; Biphenyl type epoxy resins; Hydroquinone diglycidyl ether; Resorcin diglycidyl ether etc. are mentioned preferably. Moreover, as a specific example of the glycidyl ester of an aromatic compound, a terephthalic acid diglycidyl ester, a phthalic acid diglycidyl ester, etc. are mentioned preferably.

Especially, since the glycidyl ether of an aromatic compound is more excellent in the adhesiveness at the time of adhering a polarizer and a protective film, or durability when it is set as a polarizing plate, it is especially preferable. Among the glycidyl ethers of aromatic compounds, particularly preferred compounds include diglycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and phenol novolac type epoxy resins.

The epoxy compound of (A) component can also be used individually by 1 type, and can also mix and use 2 or more types. For example, 2 or more types of aromatic epoxy compounds may be mixed and used, or an alicyclic epoxy compound may be mixed mainly as an aromatic epoxy compound.

<Oxetane compound (B)>

In the photocurable adhesive agent of this invention, if the oxetane compound used as (B) component has at least 1 oxetanyl group in a molecule | numerator, it will not specifically limit, Various compounds which have an oxetanyl group can also be used. As the oxetane compound (B), a compound having one oxetanyl group in the molecule (hereinafter referred to as "monofunctional oxetane"), and a compound having two or more oxetanyl groups in the molecule (hereinafter "polyfunctional oxetane") Is referred to as a preferred example.

Examples of monofunctional oxetane include alkoxyalkyl group-containing monofunctional oxetane such as 3-ethyl-3- (2-ethylhexyloxymethyl) oxetane, and aromatic group-containing monofunctional jade such as 3-ethyl-3-phenoxymethyloxetane. Hydroxyl group containing monofunctional oxetane, such as a cetane and 3-ethyl-3-hydroxymethyl oxetane, etc. are mentioned as a preferable example.

As polyfunctional oxetane, the following compounds are mentioned, for example.

3-ethyl-3-[(3-ethyloxetan-3-yl) methoxymethyl] oxetane,

1,4-bis [(3-ethyloxetan-3-yl) methoxymethyl] benzene,

1,4-bis [(3-ethyloxetan-3-yl) methoxy] benzene,

1,3-bis [(3-ethyloxetan-3-yl) methoxy] benzene,

1,2-bis [(3-ethyloxetan-3-yl) methoxy] benzene,

4,4'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl,

2,2'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl,

3,3 ', 5,5'-tetramethyl-4,4'-bis [(3-ethyloxetan-3-yl) methoxy] biphenyl,

2,7-bis [(3-ethyloxetan-3-yl) methoxy] naphthalene,

Bis [4-{(3-ethyloxetan-3-yl) methoxy} phenyl] methane,

Bis [2-{(3-ethyloxetan-3-yl) methoxy} phenyl] methane,

2,2-bis [4-{(3-ethyloxetan-3-yl) methoxy} phenyl] propane,

Etherified modification of novolac type phenol-formaldehyde resin with 3-chloromethyl-3-ethyloxetane,

3 (4), 8 (9) -bis [(3-ethyloxetan-3-yl) methoxymethyl] -tricyclo [5.2.1.0 ^2,6 ] decane,

2,3-bis [(3-ethyloxetan-3-yl) methoxymethyl] norbornane,

1,1,1-tris [(3-ethyloxetan-3-yl) methoxymethyl] propane,

1-butoxy-2,2-bis [(3-ethyloxetan-3-yl) methoxymethyl] butane,

1,2-bis [{2- (3-ethyloxetan-3-yl) methoxy} ethylthio] ethane,

Bis [{4- (3-ethyloxetan-3-yl) methylthio} phenyl] sulfide,

1,6-bis [(3-ethyloxetan-3-yl) methoxy] -2,2,3,3,4,4,5,5-octafluorohexane,

Hydrolyzed condensates of 3-[(3-ethyloxetan-3-yl) methoxy] propyltriethoxysilane,

Condensates of tetrakis [(3-ethyloxetan-3-yl) methyl] silicate;

It is preferable that the oxetane compound of (B) component is a liquid at room temperature of molecular weight 500 or less from a viewpoint of adhesiveness to a protective film at the time of making it coatability and a polarizing plate. Furthermore, since a polarizing plate becomes excellent in durability, as long as it is monofunctional oxetane, what has an aromatic ring in a molecule | numerator, or polyfunctional oxetane is further more preferable. Examples of such particularly preferred oxetane compounds are 3-ethyl-3-phenoxymethyloxetane, 3-ethyl-3-[(3-ethyloxetan-3-yl) methoxymethyl] oxetane and 1,4- Bis [(3-ethyloxetan-3-yl) methoxymethyl] benzene and the like.

The oxetane compound of (B) component can also be used individually by 1 type, and can also mix and use 2 or more types.

<Ratio of epoxy compound (A) and oxetane compound (B)>

The use ratio of the epoxy compound of (A) component and the oxetane compound of (B) component shall be 90/10-10/90 by the weight ratio of (A) / (B). If there is excess or deficiency in this ratio, the effect of hardening in a short time which is one of the important characteristics in the photocurable adhesive agent of this invention is not fully exhibited. The preferred weight ratio of both is about 70/30 to 20/80 since the coating property is excellent at low viscosity before curing and excellent expression of adhesiveness and flexibility after curing, and the preferred weight ratio is 60/40. To about 25/75.

<Photocationic polymerization initiator (C)>

The photocurable adhesive agent of this invention contains the epoxy compound (A) and oxetane compound (B) demonstrated above as a hardening component, and since these all harden | cure by cationic polymerization, the photocationic polymerization initiator is mix | blended as (C) component do. This photocationic polymerization initiator generates cationic species or Lewis acids by irradiation of active energy rays such as visible light, ultraviolet ray, X-ray, electron beam, and initiates a polymerization reaction of an epoxy group or an oxetanyl group.

By mix | blending a photocationic polymerization initiator as (C) component, hardening at normal temperature becomes possible, the need to consider the deformation | transformation by heat resistance, expansion | shrinkage, or shrinkage of a polarizer can be reduced, and a protective film can be adhere | attached favorably. Moreover, since a photocationic polymerization initiator acts catalytically by irradiation of an active energy ray, even if it mixes with an epoxy compound (A) and an oxetane compound (B), it is excellent in storage stability and workability. As a compound which generate | occur | produces a cationic species and Lewis acid by irradiation of an active energy ray, Onium salt, such as an aromatic diazonium salt, an aromatic iodonium salt, an aromatic sulfonium salt, an iron-arene complex, etc. are mentioned, for example.

As aromatic diazonium salt, the following compounds are mentioned, for example.

Benzenediazonium hexafluoroantimonate,

Benzenediazonium hexafluorophosphate,

Benzenediazonium hexafluoroborate and the like.

As aromatic iodonium salt, the following compounds are mentioned, for example.

Diphenyl iodonium tetrakis (pentafluorophenyl) borate,

Diphenyl iodonium hexafluorophosphate,

Diphenyl iodonium hexafluoroantimonate,

Di (4-nonylphenyl) iodonium hexafluorophosphate and the like.

As an aromatic sulfonium salt, the following compounds are mentioned, for example.

Triphenylsulfonium hexafluorophosphate,

Triphenylsulfonium hexafluoroantimonate,

Triphenylsulfonium tetrakis (pentafluorophenyl) borate,

Diphenyl [4- (phenylthio) phenyl] sulfonium hexafluorophosphate,

Diphenyl [4- (phenylthio) phenyl] sulfonium hexafluoroantimonate,

4,4'-bis (diphenylsulfonio) diphenylsulfide bishexafluorophosphate,

4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluoroantimonate,

4,4'-bis [di (β-hydroxyethoxy) phenylsulfonio] diphenylsulfide bishexafluorophosphate,

7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone hexafluoroantimonate,

7- [di (p-toluyl) sulfonio] -2-isopropylthioxanthone tetrakis (pentafluorophenyl) borate,

4-phenylcarbonyl-4'-diphenylsulfonio-diphenylsulfide hexafluorophosphate,

4- (p-tert-butylphenylcarbonyl) -4'-diphenylsulfonio-diphenylsulfide hexafluoroantimonate,

4- (p-tert-butylphenylcarbonyl) -4'-di (p-toluyl) sulfonio-diphenylsulfide tetrakis (pentafluorophenyl) borate and the like.

As an iron-arene complex, the following compounds are mentioned, for example.

Xylene-cyclopentadienyl iron (II) hexafluoroantimonate,

Cumene-cyclopentadienyl iron (II) hexafluorophosphate,

Xylene-cyclopentadienyl iron (II) -tris (trifluoromethylsulfonyl) metanide and the like.

These photocationic polymerization initiators may be used individually by 1 type, respectively, and may mix and use 2 or more types. Among these, aromatic sulfonium salts are particularly preferably used because they have excellent ultraviolet absorbing properties even in the wavelength range of 300 nm or more, and can provide a cured product having good mechanical strength and adhesive strength.

A photo cationic polymerization initiator can obtain a commercial item easily, For example, "KayaradPCI-220", "KayaradPCI-620" (above, Nippon Kayaku Co., Ltd.), and "UVI" are each a brand name. -6992 "(manufactured by Dow Chemical Co., Ltd.)," Adeka Optomer SP-150 "," Adeka Optomer SP-170 "(above, made by Adeka Co., Ltd.)," CI-5102 ", "CIT-1370", "CIT-1682", "CIP-1866S", "CIP-2048S", "CIP-2064S" (above, manufactured by Nihon Soda Co., Ltd.), "DPI-101", "DPI-102" "," DPI-103 "," DPI-105 "," MPI-103 "," MPI-105 "," BBI-101 "," BBI-102 "," BBI-103 "," BBI-105 ", "TPS-101", "TPS-102", "TPS-103", "TPS-105", "MDS-103", "MDS-105", "DTS-102", "DTS-103" (above, Midori Kagaku Co., Ltd.), "PI-2074" (Rodia Co., Ltd.), "Irgacure 250", "Irgacure PAG103", Irgacure PAG108 ", Irgacure PAG121", Irgacure PAG203 "(Above, manufactured by Shiva Corporation)," CPI-100P "," CPI-101A "," CPI-200K "," CPI-210S "(above, manufactured by San Apro Co., Ltd.), and the like. Phenyl [4 "UVI-6992" by Dow Chemical Co., Ltd. "CPI-100P", "CPI-101A", "CPI-101A", "CPI-" manufactured by Dow Chemical Company, containing-(phenylthio) phenyl] sulfonium as a cation component 200K "and" CPI-210S "are preferable.

The compounding ratio of the photocationic polymerization initiator of (C) component is 0.5-20 weight% based on the whole photocurable adhesive agent. If the ratio is less than 0.5% by weight, the curing of the adhesive is insufficient, and the mechanical strength and the adhesive strength are lowered. On the other hand, if the ratio is more than 20% by weight, the ionic substance in the cured product is increased, so that the hygroscopicity of the cured product is increased and the durability is increased. There is a possibility of deterioration in performance.

<Unsaturated compound (D)>

The photocurable adhesive agent of this invention can contain the unsaturated compound which has at least 1 ethylenically unsaturated bond in a molecule as (D) component as needed. As a typical example of such an unsaturated compound (D), the (meth) acrylic-type compound which has at least 1 (meth) acryloyl group in a molecule | numerator is mentioned.

Although it does not specifically limit as a (meth) acrylic-type compound, For example, (meth) acrylates, (meth) acrylamides, (meth) acrylic acid, (meth) acryloyl morpholine, (meth) acrylaldehyde, etc. are mentioned. Can be.

Although it does not specifically limit as (meth) acrylates (henceforth monofunctional (meth) acrylate) which has one (meth) acryloyl group in a molecule | numerator, For example, the following compounds are mentioned.

Methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, 2-ethylhexyl (meth Alkyl (meth) acrylates such as) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, lauryl (meth) acrylate and stearyl (meth) acrylate;

Hydroxyalkyl (meth) acrylates such as 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and 4-hydroxybutyl (meth) acrylate;

Cyclohexyl (meth) acrylate, isobornyl (meth) acrylate, 1,4-cyclohexanedimethylol mono (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate Alicyclic monofunctional (meth) acrylates such as dicyclopentenyloxyethyl (meth) acrylate;

Benzyl (meth) acrylate, (meth) acrylate of p-cumylphenolalkylene oxide adduct, (meth) acrylate of o-phenylphenolalkylene oxide adduct, (meth) acrylate and nonyl of phenolalkylene oxide adduct Monofunctional (meth) acrylates having the same aromatic ring as the (meth) acrylate of the phenolalkylene oxide adduct (the alkylene oxide may be ethylene oxide, propylene oxide or the like);

Alkoxyalkyl (meth) acrylates such as 2-methoxyethyl (meth) acrylate, ethoxymethyl (meth) acrylate and (meth) acrylate of alkylene oxide adducts of 2-ethylhexyl alcohol;

Mono (meth) acrylates of dihydric alcohols such as ethylene glycol mono (meth) acrylate, propylene glycol mono (meth) acrylate, pentanediol mono (meth) acrylate and hexanediol mono (meth) acrylate;

Mono (meth) acrylate of diethylene glycol, mono (meth) acrylate of triethylene glycol, mono (meth) acrylate of tetraethylene glycol, mono (meth) acrylate of polyethylene glycol, mono (meth) of dipropylene glycol Mono (meth) acrylates of polyalkylene glycols such as acrylate, mono (meth) acrylate of tripropylene glycol and mono (meth) acrylate of polypropylene glycol;

Glycidyl (meth) acrylate;

Tetrahydrofurfuryl (meth) acrylate;

Tetrahydrofurfuryl (meth) acrylates such as caprolactone-modified tetrahydrofurfuryl (meth) acrylate;

3,4-epoxycyclohexylmethyl (meth) acrylate;

N, N-dimethylaminoethyl (meth) acrylate;

2- (meth) acryloyloxyethyl isocyanate etc.

Moreover, it does not specifically limit as (meth) acrylates which have two or more (meth) acryloyl groups in a molecule | numerator, For example, the following compounds are mentioned.

Alicyclic compounds such as tricyclodecanedimethyloldi (meth) acrylate, 1,4-cyclohexanedimethyloldi (meth) acrylate, norbornanedimethyloldi (meth) acrylate and di (meth) acrylate of hydrogenated bisphenol A Di (meth) acrylates having a substituted ring;

Di (meth) acrylate and bisphenol A diglycidyl of bisphenol A alkylene oxide adduct, including di (meth) acrylate of bisphenol A ethylene oxide adduct and di (meth) acrylate of bisphenol A propylene oxide adduct Di (meth) acrylates having an aromatic ring such as di (meth) acrylate of ether;

Di (meth) acrylates of alkylene glycols such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, pentanediol di (meth) acrylate and hexanedioldi (meth) acrylate;

Diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tri Di (meth) acrylates of polyalkylene glycols such as propylene glycol di (meth) acrylate and polypropylene glycol di (meth) acrylate;

Di or tri (meth) acrylates of glycerin such as di or tri (meth) acrylate of glycerin and di or tri (meth) acrylate of diglycerin;

Di or tri (meth) acrylates of alkylene oxide adducts of glycerin;

Di (meth) acrylates of bisphenol alkylene oxide adducts such as di (meth) acrylates of bisphenol A alkylene oxide adducts and di (meth) acrylates of bisphenol F alkylene oxide adducts;

Trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylic Polyol poly (meth) acrylates such as late, dipentaerythritol penta (meth) acrylate and dipentaerythritol hexa (meth) acrylate;

Poly (meth) acrylates of alkylene oxide adducts of these polyols;

Di or tri (meth) acrylates of isocyanurate alkylene oxide adducts;

1,3,5-tri (meth) acryloylhexahydro-s-triazine and the like.

As (meth) acrylamide, (meth) acrylamide, N, N- dimethyl (meth) acrylamide, N, N- diethyl (meth) acrylamide, N-methylol (meth) acrylamide, N- ( 3-N, N-dimethylaminopropyl) (meth) acrylamide, methylenebis (meth) acrylamide, ethylenebis (meth) acrylamide, etc. are mentioned.

Moreover, oligomers, such as urethane (meth) acrylate, polyester (meth) acrylate, and epoxy (meth) acrylate, can also be used as a (meth) acrylic-type compound.

Moreover, the compound which has an ethylenically unsaturated bond other than that with a (meth) acryloyl group can also be used as a (meth) acrylic-type compound, As the specific example, allyl (meth) acrylate and N, N- diallyl (meth) ) Acrylamide, etc. are mentioned.

It does not specifically limit as (D) component, In addition to the above-mentioned (meth) acrylic-type compound, Vinyl compounds, such as N-vinyl- 2-pyrrolidone, divinyl adipic acid, and divinyl sebacate; Allyl compounds such as triallyl isocyanurate, triallylamine, tetraallyl pyromellitate, N, N, N ', N'-tetraallyl-1,4-diaminobutane, tetraallylammonium salt and allylamine; Unsaturated carboxylic acids such as maleic acid and itaconic acid may also be used.

Among the unsaturated compounds of these (D) component, a (meth) acrylic-type compound is preferable. Furthermore, when a polarizer and a protective film are adhere | attached through the adhesive agent containing it to make a polarizing plate, the (meth) acrylic-type compound which has at least 1 alicyclic skeleton or an aromatic ring skeleton in a molecule | numerator from a viewpoint of improving durability, such as heat resistance, More preferred. As a specific example of the (meth) acrylic-type compound which has at least 1 alicyclic skeleton or an aromatic ring skeleton in such a molecule | numerator, Said alicyclic monofunctional (meth) acrylates, monofunctional (meth) acrylate which has an aromatic ring, Di (meth) acrylate which has an alicyclic ring, and di (meth) acrylate which has an aromatic ring are mentioned preferably. Among these, di (meth) acrylate which especially has a tricyclodecane skeleton is preferable, and tricyclodecane dimethylol di (meth) acrylate etc. are mentioned as a specific example of such especially preferable (meth) acrylic-type compound.

The unsaturated compound of (D) component can be used in order to adjust a curing rate, adhesiveness of a polarizer and a protective film, the elasticity modulus of an adhesive layer, durability of an adhesive, etc. The unsaturated compound of (D) component can be used individually by 1 type or in mixture of 2 or more types.

When mix | blending the unsaturated compound of (D) component, it is preferable that the compounding ratio shall be 35 weight% or less based on the whole composition. Thereby, it becomes excellent in the adhesiveness of a polarizer and a protective film. When the amount of the unsaturated compound (D) exceeds 35% by weight, it is difficult to obtain sufficient adhesive strength with the polarizer. Therefore, as for the compounding ratio of an unsaturated compound (D), it is more preferable to set it as 30 weight% or less, Furthermore, about 5 to 25 weight%, It is further more preferable to set it as about 10 to 20 weight% especially.

<Photoradical Polymerization Initiator (E)>

When the photocurable adhesive agent of this invention contains the unsaturated compound of (D) component, it is preferable to mix | blend an radical photopolymerization initiator as (E) component in order to promote the radical polymerization property and to make hardening rate sufficient.

Although it does not specifically limit as a specific example of the radical photopolymerization initiator used as (E) component, For example, the following compounds are mentioned.

4'-phenoxy-2,2-dichloroacetophenone, 4'-tert-butyl-2,2-dichloroacetophenone, 2,2-dimethoxy-2-phenylacetophenone, 2-methyl-1- (4 -Methylthiophenyl) -2-morpholinopropane-1-one, 1-hydroxycyclohexylphenyl ketone, α, α-diethoxyacetophenone, 2-hydroxy-2-methyl-1-phenylpropane-1 -One, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 1- (4-dodecylphenyl) -2-hydroxy-2-methylpropan-1-one , 1- [4- (2-hydroxyethoxy) phenyl] -2-hydroxy-2-methylpropan-1-one and 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) Acetophenone type photoinitiators, such as butan-1-one;

Benzoin ether photopolymerization initiators such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

Benzophenone-based photopolymerization initiators such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide and 2,4,6-trimethylbenzophenone;

Thioxanthone type photoinitiator, such as 2-isopropyl thioxanthone, 2, 4- diethyl thioxanthone, 2, 4- dichloro thioxanthone, and 1-chloro-4- propoxy thioxanthone;

2,4,6-trimethylbenzoyldiphenylphosphineoxide, bis (2,6-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphineoxide and bis (2,4,6-trimethylbenzoyl) phenylforce Acyl phosphine oxide type photoinitiators, such as a pin oxide;

Oxime ester photoinitiators such as 1,2-octanedione, 1- [4- (phenylthiophenyl)]-, and 2- (O-benzoyloxime);

Camphorquinone and the like.

The radical photopolymerization initiator of (E) component can be used individually by 1 type or in mixture of 2 or more types according to desired performance. When mix | blending the radical photopolymerization initiator of (E) component, 10 weight% or less is preferable with respect to the whole composition, and, as for the compounding ratio, about 0.1-3 weight% is more preferable. When the amount of the radical photopolymerization initiator (E) is too large, sufficient strength may not be obtained, and when the amount is insufficient, the adhesive may not be sufficiently cured.

<Other ingredients>

Moreover, the component which is different from the said (A)-(E) component can be mix | blended arbitrarily to the photocurable adhesive agent of this invention in the range which does not impair the effect of this invention. As one type which belongs to such another component, the compound which has cation polymerization property other than the epoxy compound of (A) component and the oxetane compound of (B) component is mentioned, Although it does not specifically limit as the specific example, The epoxy compound etc. which have an epoxy group are mentioned. Moreover, the other component (F) which does not have polymerizability is mentioned as another type which belongs to another component. When mix | blending the other component (F) which does not have polymerizability, it is preferable to make the compounding ratio into about 10 weight% or less based on the whole composition.

Although it does not specifically limit as an example of another component (F) which does not have polymerizability, A photosensitizer is mentioned. By mix | blending a photosensitizer, reactivity improves and the mechanical strength and adhesive strength of hardened | cured material can be improved. Examples of the photosensitizer include carbonyl compounds, organic sulfur compounds, persulfides, redox compounds, azo and diazo compounds, halogen compounds, photoreducing dyes, and the like.

It does not specifically limit as a specific photosensitizer, For example, the following compounds are mentioned.

Benzoin derivatives such as benzoin methyl ether, benzoin isopropyl ether and α, α-dimethoxy-α-phenylacetophenone;

Benzophenone derivatives such as benzophenone, 2,4-dichlorobenzophenone, methyl o-benzoylbenzoate, 4,4'-bis (dimethylamino) benzophenone and 4,4'-bis (diethylamino) benzophenone;

Thioxanthone derivatives such as 2-chlorothioxanthone and 2-isopropyl thioxanthone;

Anthraquinone derivatives such as 2-chloroanthraquinone and 2-methylanthraquinone;

Acridon derivatives such as N-methylacridone and N-butylacridone;

Others, α, α-diethoxyacetophenone, benzyl, fluorenone, xanthone, uranyl compound, halogen compound and the like.

Among these, there are also compounds corresponding to the radical photopolymerization initiator of the component (E), and the photosensitizer described herein is not particularly limited as long as it functions as a sensitizer for the photocationic polymerization initiator of the component (C). These may be used independently, respectively and may mix and use 2 or more types.

A photosensitizer includes the cationically polymerizable monomer [the said epoxy compound (A) and an oxetane compound (B) in the photocurable adhesive agent of this invention, and when the compound which has the above-mentioned other cationically polymerizable compound is mix | blended, it also contains it. It is preferable to make into 100 weight part and contain in 0.1-20 weight part.

Moreover, a thermal cationic polymerization initiator can also be used as another component (F) which does not have polymerizability. Benzylsulfonium salt, thiophenium salt, thiornium salt, benzyl ammonium salt, pyridinium salt, hydrazinium salt, carboxylic acid ester, sulfonic acid ester, amine imide etc. are mentioned as a thermal cationic polymerization initiator. These initiators can obtain a commercial item easily, For example, all are represented by a brand name, "Adeka Opton CP77" and "Adeka Opton CP66" (above, made by Adeka Co., Ltd.), "CI-2639" And "CI-2624" (above, manufactured by Nihon Soda Co., Ltd.), "Sunade SI-60L", "Sunade SI-80L", and "Sunade SI-100L" (above, Sanshin Kagaku Kogyo Co., Ltd.) Production).

Since polyols have the property of promoting cationic polymerization, they can be used as other component (F) which also does not have polymerizability. As polyol, it is preferable that acidic groups other than a phenolic hydroxyl group do not exist, For example, the polyol compound which does not have functional groups other than a hydroxyl group, a polyester polyol compound, a polycaprolactone polyol compound, the polyol compound which has a phenolic hydroxyl group, A polycarbonate polyol compound etc. are mentioned.

Moreover, as another component (F) which does not have polymerizability, unless the effect of this invention is impaired, a silane coupling agent, an ion trap agent, antioxidant, a light stabilizer, a chain transfer agent, a sensitizer, a tackifier, a thermoplastic resin, A filler, a flow regulator, a plasticizer, an antifoamer, a leveling agent, a pigment | dye, an organic solvent, etc. can also be mix | blended. As another component (F) which does not have polymerizability, it is also effective to mix | blend a thermoplastic resin for the purpose of further improving adhesiveness with a protective film. It is preferable that a glass transition temperature is 70 degreeC or more from a viewpoint of improving durability of a polarizer as a thermoplastic resin, A methylmethacrylate type polymer etc. are mentioned as an especially preferable example.

[Polarizing Plate]

The photocurable adhesive agent demonstrated above is uniaxially stretched, and is used in order to adhere | attach a protective film to the polarizer which consists of a polyvinyl alcohol-type resin film in which the dichroic dye was adsorption-oriented, In this way, a protective film is bonded to a polarizer and it becomes a polarizing plate. That is, the polarizing plate which concerns on this invention is uniaxially stretched, and if a protective film is bonded to the polarizer which consists of a polyvinyl alcohol-type resin film by which the dichroic dye was adsorption-oriented, it will not specifically limit. The protective film may be bonded only to one surface of the polarizer or may be bonded to both surfaces of the polarizer. When bonding a protective film on both surfaces of a polarizer, each protective film may consist of the same kind of resin, and may consist of another kind of resin.

<Polarizer>

Polyvinyl alcohol-type resin which comprises a polarizer is obtained by saponifying polyvinyl acetate type resin. As polyvinyl acetate type resin, the copolymer etc. of vinyl acetate and the other monomer copolymerizable with this besides the polyvinyl acetate which is a homopolymer of vinyl acetate are illustrated. As another monomer copolymerized with vinyl acetate, unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, etc. are mentioned, for example. Although the saponification degree of polyvinyl alcohol-type resin is not specifically limited, Usually, it is 85-100 mol%, and the range of 98-100 mol% is preferable. The polyvinyl alcohol-based resin may also be modified. For example, polyvinyl formal, polyvinyl acetal, or the like modified with aldehydes can also be used. Although the polymerization degree of polyvinyl alcohol-type resin is not specifically limited, Usually, it is 1,000-10,000, and the range of 1,500-10,000 is preferable.

The polarizing plate is a step of uniaxially stretching such a polyvinyl alcohol-based resin film, dyeing the polyvinyl alcohol-based resin film with a dichroic dye, adsorbing the dichroic dye, and a polyvinyl alcohol-based resin film adsorbed with the dichroic dye. It is manufactured through the process of treating with a boric-acid aqueous solution, the process of washing with water after the treatment with an aqueous boric acid solution, and these processes, and a process of bonding a protective film to the uniaxially-stretched polyvinyl alcohol-type resin film by which the dichroic dye was adsorption-oriented.

Uniaxial stretching may be performed before dyeing with a dichroic dye, simultaneously with dyeing with a dichroic dye, or after dyeing with a dichroic dye. When uniaxial stretching is performed after dyeing with a dichroic dye, this uniaxial stretching may be performed before boric acid treatment, or may be performed during boric acid treatment. Of course, it is also possible to uniaxially stretch in these several steps. In order to uniaxially stretch, you may extend | stretch uniaxially between rolls from which a circumferential speed differs, and you may extend | stretch uniaxially using a thermal roll. Moreover, it may be dry stretching which extends | stretches in air | atmosphere, and wet extending | stretching which extends | stretches in the state swelled with a solvent may be sufficient. The draw ratio is not particularly limited, but is usually about 4 to 8 times.

In order to dye a polyvinyl alcohol-type resin film with a dichroic dye, what is necessary is just to immerse a polyvinyl alcohol-type resin film in the aqueous solution containing a dichroic dye, for example. As a dichroic dye, an iodine or a dichroic dye is specifically used.

When using iodine as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing iodine and potassium iodide is employ | adopted normally. Although content of iodine in this aqueous solution is not specifically limited, Usually, it is about 0.01-0.5 weight part per 100 weight part of water, and content of potassium iodide is not specifically limited, Usually, it is about 0.5-10 weight part per 100 weight part of water. Although the temperature of this aqueous solution is not specifically limited, Usually, it is about 20-40 degreeC, and the immersion time in this aqueous solution is although it does not specifically limit, Usually, it is about 30 to 300 second.

On the other hand, when using a dichroic dye as a dichroic dye, the method of immersing and dyeing a polyvinyl alcohol-type resin film in the aqueous solution containing water-soluble dichroic dye is employ | adopted normally. The content of the dichroic dye in this aqueous solution is not particularly limited, it is usually water per 100 parts by weight of 1 × 10 ^-3 to 1 × 10 ^-2 parts by weight. This aqueous solution may contain inorganic salts, such as sodium sulfate. Although the temperature of this aqueous solution is not specifically limited, Usually, it is about 20-80 degreeC, and the immersion time in this aqueous solution is although it does not specifically limit, Usually, it is about 30 to 300 second.

Boric acid treatment after dyeing with a dichroic dye is performed by immersing the dyed polyvinyl alcohol-type resin film in boric-acid aqueous solution. Although content of boric acid in boric-acid aqueous solution is not specifically limited, Usually, about 2-15 weight part per 100 weight part of water, Preferably it is about 5-12 weight part. When using iodine as a dichroic dye, it is preferable that this boric-acid aqueous solution contains potassium iodide. Although content of potassium iodide in boric-acid aqueous solution is not specifically limited, Usually, about 2-20 weight part per 100 weight part of water, Preferably it is 5-15 weight part. Although the immersion time in boric-acid aqueous solution is not specifically limited, Usually, it is about 100 to 1,200 second, Preferably it is about 150 to 600 second, More preferably, it is about 200 to 400 second. Although the temperature of boric-acid aqueous solution is not specifically limited, Usually, it is 50 degreeC or more, Preferably it is 50-85 degreeC.

The polyvinyl alcohol-based resin film after boric acid treatment is usually washed with water. The water washing process is performed by immersing the polyvinyl alcohol-type resin film processed by boric acid in water, for example. After washing with water, a drying treatment is performed to obtain a polarizer. Although the temperature of the water in a water washing process is not specifically limited, Usually, it is about 5-40 degreeC, and immersion time is although it does not specifically limit, Usually, it is about 2 to 120 second. The drying process performed after that is normally performed using a hot air dryer or a far-infrared heater. Although drying temperature is not specifically limited, Usually, it is 40-100 degreeC. Although the processing time in a drying process is not specifically limited, Usually, it is about 120 to 600 second.

In this way, the polarizer which consists of a polyvinyl alcohol-type resin film by which the iodine which is a dichroic dye or a dichroic dye was adsorption-oriented is obtained.

<Shield>

Subsequently, this polarizer uses the photocurable adhesive agent mentioned above, and a protective film is bonded by the one side or both surfaces. As a protective film of the polarizer triacetyl widely employed conventionally cellulose film was approximately 400 g / m ^2/24 hr gatneunde the degree of moisture permeability of the present invention, these triacetyl cellulose than the low moisture permeability as a protective film is bonded on at least one side of the polarizer Polyester resin, polycarbonate resin, or acrylic resin is employ | adopted as resin which shows.

Although the kind of polyester resin used for a protective film is not specifically limited, A polyethylene terephthalate is especially preferable from a viewpoint of mechanical property, solvent resistance, scratch resistance, cost, etc. Polyethylene terephthalate means resin in which 80 mol% or more of a repeating unit is comprised from ethylene terephthalate, and may contain the structural unit derived from another copolymerization component. As another copolymerization component, isophthalic acid, p- (beta) -hydroxyethoxy benzoic acid, 4,4'- dicarboxydiphenyl, 4,4'- dicarboxy benzophenone, bis (4-carboxyphenyl) ethane, adipic acid Dicarboxylic acid components such as sebacic acid, 5-sodium sulfoisophthalic acid and 1,4-dicarboxycyclohexane; And diol components such as propylene glycol, butanediol, neopentyl glycol, diethylene glycol, cyclohexanediol, ethylene oxide adducts of bisphenol A, polyethylene glycol, polypropylene glycol, and polytetramethylene glycol. These dicarboxylic acid components and diol components can also be used in combination of 2 or more type, respectively as needed. Moreover, it is also possible to use together the hydroxycarboxylic acid like p-hydroxybenzoic acid with the said dicarboxylic acid component and the diol component. As other copolymerization component, a small amount of dicarboxylic acid component and / or diol component having an amide bond, urethane bond, ether bond, carbonate bond and the like may be used.

As a manufacturing method of a polyester resin, what is called direct polymerization method which directly reacts terephthalic acid and ethylene glycol (another dicarboxylic acid and / or other diol as needed), the dimethyl ester of terephthalic acid, and ethylene glycol (as needed) Therefore, arbitrary methods, such as what is called a transesterification method of transesterifying the dimethyl ester of another dicarboxylic acid and / or another diol), can be employ | adopted. In addition, the polyester resin may contain a well-known additive as needed. Although it does not specifically limit as an additive which can be contained, For example, a lubricating agent, an antiblocking agent, a heat stabilizer, antioxidant, an antistatic agent, a light resistance agent, an impact resistance improvement agent, etc. are mentioned. However, since transparency is needed as a protective film laminated | stacked on a polarizing film, it is preferable to suppress the quantity of these additives to the minimum.

The protective film which consists of stretched polyester resin can be produced by shape | molding the said raw material resin into a film form, and performing uniaxial stretching or biaxial stretching process. By performing an extending | stretching process, the film with high mechanical strength can be obtained. Although the manufacturing method of the stretched polyester resin film is arbitrary and it is not specifically limited, After heat-extending the tentatively oriented film | membrane which melted the said raw material resin and extruded into the sheet form by the tenter at the temperature more than glass transition temperature, it heat-fixed The method of performing a process is mentioned.

The polycarbonate resin used for the protective film is preferably a polyester formed from carbonic acid, glycol or bisphenol. Especially, the aromatic polycarbonate which has diphenyl alkane in a molecular chain is used preferably because it is excellent in heat resistance, weather resistance, and acid resistance. As such polycarbonate, 2, 2-bis (4-hydroxyphenyl) propane (alias bisphenol A), 2, 2-bis (4-hydroxyphenyl) butane, 1, 1-bis (4-hydroxyphenyl) Polycarbonates derived from bisphenols such as cyclohexane, 1,1-bis (4-hydroxyphenyl) isobutane or 1,1-bis (4-hydroxyphenyl) ethane are exemplified.

As a manufacturing method of a polycarbonate resin film, you may use any method, such as a casting film forming method and a melt-extrusion method. As an example of a specific manufacturing method, a polycarbonate resin is dissolved in a suitable organic solvent to form a polycarbonate resin solution, which is cast on a metal support to form a web, the web is peeled off from the metal support, and then peeled off. The method of drying by hot air and obtaining a film is mentioned.

Although acrylic resin used for a protective film is not specifically limited, Usually, the copolymer which makes methacrylic acid ester the monomer which is a main component, and is copolymerized with a small amount of other comonomer components is preferable. As methacrylic acid ester which becomes a main component of an acrylic resin, alkyl methacrylate is mentioned preferably, Especially methyl methacrylate is used preferably. In addition, the comonomer component is not particularly limited, but methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethyl-hexyl acrylate and the like are generally used. In addition, an aromatic vinyl compound such as styrene or a vinyl cyan compound such as acrylonitrile may be used as a comonomer component.

As a manufacturing method of an acrylic resin, arbitrary methods, such as normal block polymerization, suspension polymerization, and emulsion polymerization, can be employ | adopted. Among these, especially the bulk polymerization in which the water-soluble component does not exist in a polymerization system is employ | adopted preferably. In addition, it is preferable to use a chain transfer agent at the time of superposition | polymerization, in order to obtain a preferable glass transition temperature or to obtain the viscosity which shows moldability to a preferable film. What is necessary is just to determine the quantity of a chain transfer agent suitably according to the kind and composition of a monomer. In addition, the acrylic resin may contain the well-known additive as needed. As a well-known additive, a lubricant, an antiblocking agent, a heat stabilizer, antioxidant, an antistatic agent, a light resistant agent, an impact resistance improving agent, surfactant, etc. are mentioned, for example. However, since transparency is needed as a protective film laminated | stacked on a polarizing film, it is preferable to suppress the quantity of these additives to the minimum.

As a manufacturing method of an acrylic resin film, you may use any method, such as a melt casting method, the melt-extruding method like the T-die method and the inflation method, the calendar method. Especially, the method of melt-extruding raw material resin from a T die, for example, and contacting at least one surface of the obtained film-form thing with a roll or a belt is preferable at the point from which the film with a favorable surface property is obtained.

The acrylic resin may contain acrylic rubber particles, which are impact modifiers, in terms of film forming property to a film, impact resistance of the film, and the like. The acrylic rubber particles referred to herein are not particularly limited as long as they are particles having an elastomer mainly composed of acrylate ester as an essential component, and have a single layer structure substantially composed of only this elastomer, or a multilayer structure having this elastomer as one layer. This can be mentioned as an example. As an example of such an elastic polymer, the crosslinked elastic copolymer which made alkylacrylate the main component and copolymerized the other vinyl monomer and crosslinkable monomer which can be copolymerized to this is mentioned. As alkyl acrylate which becomes a main component of an elastic polymer, C1-C8 thing of alkyl groups, such as methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, is mentioned, for example, Especially carbon number is mentioned. An acrylate having four or more alkyl groups is preferably used. As another vinyl monomer copolymerizable with this alkylacrylate, the compound which has one polymerizable carbon-carbon double bond in a molecule | numerator is mentioned, More specifically, methacrylic acid ester like methyl methacrylate, aromatic vinyl like styrene And vinyl cyan compounds such as acrylonitrile. Moreover, as a crosslinkable monomer, the crosslinkable compound which has at least 2 polymerizable carbon-carbon double bond in a molecule | numerator is mentioned, More specifically, Ethylene glycol di (meth) acrylate and butanediol di (meth) acrylate, (Meth) acrylates of the same polyhydric alcohol, alkenyl ester of (meth) acrylic acid, such as allyl (meth) acrylate, divinylbenzene, etc. are mentioned.

Moreover, the laminated body of the film which consists of acrylic resin which does not contain rubber particle, and the film which consists of acrylic resin containing rubber particle can also be made into a protective film.

In the polarizing plate used for the visual recognition side of a liquid crystal display device, anti-glare property can be provided to the visual recognition side, ie, the protective film arrange | positioned on the opposite side to a liquid crystal cell. In this case, the anti-glare layer which has surface unevenness | corrugation is generally provided in the surface used as the visual recognition side of a protective film, ie, the surface opposite to the surface joined to a polarizer. An anti-glare layer is generally formed by giving an unevenness | corrugation to active energy ray curable resin by embossing, or giving an unevenness | corrugation by mix | blending and hardening fine particles which have a refractive index different from it to active energy ray curable resin. In addition, when a protective film is comprised from an acrylic resin, it is a laminated film of the light-diffusion layer which mix | blended microparticles | fine-particles which have a refractive index different from it in the acrylic resin used as a binder, and the transparent layer which consists of acrylic resin in which such microparticles | fine-particles are not mix | blended. It is also effective to construct a protective film. In this case, the laminated film which consists of two layers of said light-diffusion layer and said transparent layer is bonded to the polarizer in the light-diffusion layer side, or the lamination | stacking of the three-layer structure which sandwiched both surfaces of the said light-diffusion layer between the said transparent layers. The form etc. which bond a film to a polarizer with the one transparent layer can be employ | adopted. Furthermore, even when using the acrylic resin laminated | multilayer film to which anti-glare property was provided by including such a light-diffusion layer as a protective film, the anti-glare layer as mentioned above on the surface used as the visibility side, ie, the surface opposite to the surface bonded to a polarizer, is mentioned. It is also effective to increase the anti-glare performance by installing a.

As mentioned above, especially when an acrylic resin film is used as a protective film, it is necessarily sufficient that adhesiveness is sufficient as the epoxy resin single body which does not contain the aromatic ring shown by the said patent document 6 (Unexamined-Japanese-Patent No. 2004-245925). The photocurable adhesive agent of this invention provides the favorable adhesive force even when this acrylic resin film is used as a protective film. Therefore, this invention is especially useful when making an acrylic resin film a protective film. In this case, it is more preferable to contain the unsaturated compound of (D) component mentioned above, especially an acryl-type compound in a photocurable adhesive agent.

In this invention, the protective film which consists of a transparent resin film chosen from the polyester resin, polycarbonate resin, and acrylic resin demonstrated above on at least one surface of a polarizer is bonded through the photocurable adhesive agent mentioned above. When bonding a protective film only to one side of a polarizer, it is also possible to take the form of directly providing the adhesive layer for bonding to another member, such as a liquid crystal cell, on the other surface of a polarizer, for example.

On the other hand, when bonding a protective film on both surfaces of a polarizer, each protective film may be the same kind or may be a different kind. Specifically, the form which bonds a polyester resin film to both surfaces of a polarizer as a protective film, the form which bonds a polycarbonate resin as a protective film to both surfaces of a polarizer, the form which bonds acrylic resin as a protective film to both surfaces of a polarizer, and a polarizer One of the transparent resin films selected from polyester resins, polycarbonate resins and acrylic resins is bonded as a protective film to one side of the substrate, and the other side of the polarizer is any one selected from polyester resins, polycarbonate resins and acrylic resins. And the aspect which joins the transparent resin film different from the protective film of the said one surface as a protective film, etc. can be employ | adopted preferably. Moreover, one transparent resin film selected from polyester resin, polycarbonate resin, and acrylic resin is bonded to one side of a polarizer as a protective film, and the other side of a polarizer is any of polyester resin, polycarbonate resin, and acrylic resin. Moreover, the aspect which bonds another transparent resin film as a protective film can also be employ | adopted. When joining a protective film on both surfaces of a polarizer, two protective films may be joined one by one at a time, and both surfaces may be bonded by one step.

When bonding a protective film to both surfaces of a polarizer and making one of these into another resin film different from a polyester resin, a polycarbonate resin, and an acrylic resin, As a preferable example of this other resin, a cellulose resin or an amorphous polyolefin A system resin is mentioned as an example. Further, the protective film made of polyester resin, polycarbonate resin or acrylic resin bonded to one side of the polarizer is adhered through the photocurable adhesive described above according to the present invention, while the protective film bonded to the other side of the polarizer is different adhesive. It may be bonded through. For example, in the case where a protective film made of a resin film having a relatively high moisture permeability, such as a cellulose resin film, is provided on one side of the polarizer, the bonding surface of such a resin film having a high moisture permeability is other than an epoxy resin such as a polyvinyl alcohol adhesive. Adhesives can also be used. However, since the photocurable adhesive agent of this invention provides a high adhesive force also with respect to the cellulose resin film and amorphous polyolefin resin film illustrated here, since the operation using the same adhesive on both surfaces of a polarizer becomes simpler, It is advantageous.

The cellulose resin which can be used as one protective film is a partial or complete esterified cellulose, for example, an acetate ester of cellulose, propionic acid ester, butyric acid ester, mixed ester thereof, and the like. Specific examples thereof include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like. Although it does not specifically limit as an example of the commercial item of the film which consists of such cellulose ester-type resins, "Fuji Tak TD80", "Fuji Tak TD80UF" and "Fuji Tak TD80UZ" by Fuji Film Co., Ltd. " KC8UX2M "," KC8UY ", etc. are mentioned. Moreover, the cellulose resin film provided with the optical compensation function can also be used. Although it does not specifically limit as such an optical compensation film, For example, the film in which the compound which has a phase difference adjustment function was contained in cellulose resin, the thing in which the compound which has a phase difference adjustment function was apply | coated to the surface of a cellulose resin film, a cellulose resin film The film etc. which are obtained by extending | stretching uniaxially or biaxially are mentioned. Examples of commercially available cellulose-based optical compensation films include "Wide View Film WV BZ 438" and "Wide View Film WV EA" manufactured by Fuji Film Co., Ltd., and "KC4FR-1" manufactured by Konica Minolta Opto Co., Ltd. And "KC4HR-1" are mentioned preferably.

Other resins different from polyester resins, polycarbonate resins and acrylic resins are not particularly limited as examples of transparent water-repellent transparent resins that can be used as one protective film, but are not limited to amorphous polyolefin resins, polysulfone resins, and alicyclic polyimides. Resin and the like. Among these, the film which consists of amorphous polyolefin resin is used especially suitably as a film excellent in mechanical property, solvent resistance, scratch resistance, cost, etc.

Amorphous polyolefin resins usually have polymerized units derived from polycyclic cyclic olefins such as norbornene, derivatives thereof and dimethanooctahydronaphthalene, and when double bonds remain like a ring-opening polymer, hydrogen is added thereto. Preferred thermoplastic resins are preferred. The amorphous polyolefin resin may be a copolymer of a cyclic olefin and a chain olefin, or a polar group may be introduced. Especially, as a typical example, thermoplastic saturated norbornene-type resin is mentioned. Examples of commercially available amorphous polyolefin resins include "Aton" by JSR, "ZEONEX" and "ZEONOR" by Nihon Xeon, "APO" and "Apel" by Mitsui Chemical Industries, Ltd. There is this. When forming amorphous polyolefin resin into a film, well-known methods, such as a solvent casting method and a melt extrusion method, are used suitably for film forming.

The protective film may be subjected to reverse adhesion treatment such as saponification treatment, corona treatment, primer treatment, anchor coating treatment, and the like on the bonding surface prior to bonding to the polarizer. Moreover, you may have various process layers, such as a hard coat layer, an antireflection layer, an anti-glare layer, on the surface on the opposite side to the bonding surface of a protective film to the polarizer. Although the thickness of a protective film is not specifically limited, Usually, it is the range of about 5-200 micrometers, Preferably it is 10-120 micrometers, More preferably, it is 10-85 micrometers.

[Method for Manufacturing Polarizing Plate]

The polarizing plate of this invention is obtained by the adhesive agent application process which apply | coats the photocurable adhesive agent mentioned above to at least one of the bonding surface of the polarizer mentioned above and the protective film which consists of a transparent resin film chosen from polyester resin, a polycarbonate resin, and an acrylic resin, It can manufacture by the method including the bonding process which bonds a polarizer and a protective film through an adhesive bond layer, and the hardening process which hardens a photocurable adhesive agent in the state which bonded the polarizer and a protective film through this adhesive bond layer.

<Adhesive application process>

In the adhesive agent applying process, the photocurable adhesive agent mentioned above is apply | coated to at least one of the bonding surface of a polarizer and a protective film. When apply | coating a photocurable adhesive agent directly to the surface of a polarizer or a protective film, there is no special limitation in the coating method. For example, various coating methods, such as a doctor blade, a wire bar, a die coater, a comma coater, and a gravure coater, can be used. Moreover, after softening the above-mentioned photocurable adhesive agent between a polarizer and a protective film, the method of pressurizing with a roll etc. uniformly and spreading can also be used.

<Bonding process>

In this way, after apply | coating a photocurable adhesive agent, it is provided to a bonding process. In this bonding process, when a photocurable adhesive agent is apply | coated to the surface of a polarizer in the said application | coating process, for example, when a protective film is superimposed thereon and when a photocurable adhesive agent is apply | coated to the surface of a protective film in the said application | coating process, there The polarizer is superimposed on. In addition, when a photocurable adhesive agent is cast between a polarizer and a protective film, a polarizer and a protective film overlap in that state. As a case where a protective film is bonded to both surfaces of a polarizer, when both surfaces use the photocurable adhesive agent of this invention, a protective film superimposes on both surfaces of a polarizer via a photocurable adhesive agent, respectively. Usually, in this state, when a protective film is superimposed on one side of a polarizer, a polarizer side and a protective film side, and when a protective film is superimposed on both surfaces of a polarizer, the protective film side of both surfaces are between rolls etc. Pressurized. Here, the material of a roll can use a metal, rubber | gum, etc. The rolls arranged on both sides may be the same material or different materials.

<Hardening process>

As mentioned above, the thing of the state in which the polarizer and the protective film were joined through the uncured photocurable adhesive agent is provided to a hardening process next. In this curing process, an active energy ray is irradiated to a photocurable adhesive agent, the adhesive bond layer containing an epoxy compound or an oxetane compound is hardened | cured, and a polarizer and a protective film are adhere | attached. When the protective film is bonded to one surface of the polarizer, the active energy ray may be irradiated from either the polarizer side or the protective film side. In addition, when bonding a protective film on both surfaces of a polarizer, an active energy ray is irradiated from either side of a protective film in the state which bonded the protective film to the both surfaces of a polarizer through the photocurable adhesive agent, respectively, and simultaneously the both sides photocurable adhesive agent It is advantageous to cure. However, when the ultraviolet absorber is compounded in one of the protective films (for example, when the cellulose-based resin film containing the ultraviolet absorber is used as one protective film), and the active energy ray is ultraviolet light, the other Ultraviolet rays are irradiated from the protective film side where no ultraviolet absorber is blended.

As active energy rays, visible rays, ultraviolet rays, X-rays, electron beams and the like can be used. In general, ultraviolet rays are preferably used because they are easy to handle and have a sufficient curing rate. 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 lamp which have luminescence distribution in wavelength below 400 nm , LED lamps and the like can be used.

The light irradiation intensity to the photocurable adhesive agent is determined for each desired composition, and is not particularly limited, but the irradiation intensity in the wavelength range effective for the activation of the polymerization initiator is UV-B (mid-wavelength ultraviolet ray of 280 to 320 nm). It is preferred to be 1 to 3,000 mW / cm ² . When the irradiation intensity is less than 1 mW / cm ² , the reaction time is long. On the other hand, when the irradiation intensity exceeds 3,000 mW / cm ² , the photocurable adhesive is generated by the heat generated during polymerization of the heat and the photocurable adhesive radiated from the lamp. There is a possibility of causing yellowing and deterioration of the polarizer.

Light irradiation time to a photocurable adhesive agent is controlled for every composition to be hardened | cured, Although it does not specifically limit, It is preferable to set so that accumulated light quantity expressed by the product of irradiation intensity and irradiation time may be 10-5,000 mJ / cm <^2> . . If the accumulated light amount is less than 10 mJ / cm ² , there is a possibility that the generation of active species derived from the polymerization initiator may not be sufficient, so that curing of the adhesive layer may be insufficient, while if the accumulated light amount exceeds 5,000 mJ / cm ² , the irradiation time This becomes very long and becomes disadvantageous for productivity improvement.

In hardening a photocurable adhesive agent by irradiating an active energy ray, it is preferable to harden on the conditions which the various functions of a polarizing plate, such as polarization degree, a transmittance | permeability, a color, and transparency of a protective film, do not fall.

In the polarizing plate obtained in this way, although the thickness of an adhesive bond layer is not specifically limited, Usually, 50 micrometers or less, Preferably it is 20 micrometers or less, More preferably, it is 10 micrometers or less.

[Optical member]

In use of a polarizing plate, it can also be set as the optical member which laminated | stacked the optical layer which shows optical functions other than a polarizing function on the one side. Although it does not specifically limit as an optical layer laminated | stacked on a polarizing plate for the purpose of formation of an optical member, For example, it is used for formation of a liquid crystal display device, such as a reflection layer, a transflective reflection layer, a light-diffusion layer, a retardation plate, a light collecting plate, a brightness enhancement film, etc. Various things can be mentioned. The reflecting layer, semi-transmissive reflecting layer, and light diffusing layer are used when forming an optical member made of a reflective to semi-transmissive type, diffused type, and a dual-use polarizing plate.

A reflective polarizing plate is used for a liquid crystal display device of the type which reflects and displays incident light from the viewer side, and since a light source such as a backlight can be omitted, the liquid crystal display device is easily thinned. In addition, the semi-transmissive polarizing plate is used for a liquid crystal display device of the type which displays as a reflection type in a spot, and uses a light source, such as a backlight, in the dark. The optical member as a reflective polarizing plate can form a reflective layer by, for example, laying a foil or a vapor deposition film made of a metal such as aluminum on a protective film on the polarizer. The optical member as a semi-transmissive polarizing plate can be formed by making the said reflection layer into a half mirror, or adhering a 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 surface is surfaced using various methods, such as the method of performing a mat process to the protective film on a polarizing plate, the method of apply | coating microparticles-containing resin, the method of adhering a film containing microparticles | fine-particles, etc. To form a fine uneven structure.

In addition, formation of the optical member as a polarizing plate for both reflection and diffusion can be performed by the method of providing the reflecting 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 an advantage of diffusing incident light by diffuse reflection, preventing directivity and fluctuations, and suppressing unevenness in contrast. Moreover, the resin layer and film containing microparticles | fine-particles also have the advantage that it can spread | diffuse when incident light and its reflected light permeate | transmit a 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 depositing a metal on 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, inorganic type microparticles | fine-particles containing silica, aluminum oxide, titanium oxide, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, etc. with an average particle diameter of 0.1-30 micrometers, for example Organic fine particles containing a crosslinked or uncrosslinked polymer or the like can be used.

On the other hand, the retardation plate as the optical layer is used for the purpose of compensating the retardation by the liquid crystal cell or the like. Although it does not specifically limit as an example, The birefringent film which consists of stretched films, etc. of various plastics, The film in which the discotic liquid crystal and the nematic liquid crystal were orientally fixed, The thing in which the said liquid crystal layer was formed on the film base material, etc. are mentioned. In this case, although it does not specifically limit as a film base material which supports an orientation liquid crystal layer, Cellulose-type films, such as a triacetyl cellulose, are used preferably.

Although it does not specifically limit as a plastic which forms a birefringent film, For example, polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polyolefin like polypropylene, polyarylate, polyamide, amorphous polyolefin resin, etc. Can be mentioned. 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, the retarder may be used in combination of two or more sheets for the purpose of controlling optical characteristics such as widening.

The light collecting plate is used for the purpose of optical path control or the like, and can be formed as a prism array sheet, a lens array sheet, a dot laying sheet, or the like.

The brightness enhancing film is used for the purpose of improving the brightness in a liquid crystal display device. Examples thereof include a reflective linear polarized light separating sheet designed to produce anisotropy in reflectance by laminating a plurality of thin film films having different refractive anisotropy, The circularly polarized light separating sheet which supported the orientation film of the cholesteric liquid crystal polymer and this orientation 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 from the above-described reflective layers to semi-transmissive reflective layers, light diffusing layers, retardation plates, light collecting plates, brightness enhancement films, and the like. It can be set as a laminated body of layers or more. 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.

Various optical layers for forming the optical member are integrated with the polarizing plate using an adhesive, but the adhesive used for the optical member is not particularly limited as long as the adhesive layer is formed satisfactorily. It is preferable to use an adhesive (also called a pressure-sensitive adhesive) from the standpoint of simplicity of bonding operation and prevention of occurrence of optical distortion. 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 cohesive force, is excellent in adhesiveness with a substrate, and furthermore has weather resistance, heat resistance, and the like. It is preferable to select and use the thing which does not produce a peeling problem. In the acrylic pressure sensitive adhesive, a functional group-containing acrylic monomer containing an alkyl ester of (meth) acrylic acid having an alkyl group having 20 or less carbon atoms such as a methyl group, an ethyl group or a butyl group, and (meth) acrylic acid, hydroxyethyl (meth) acrylate, etc. An acrylic copolymer having a weight average molecular weight of 100,000 or more that is blended and polymerized so that the glass transition temperature is preferably 25 ° C. or lower, more preferably 0 ° C. or lower is useful as the base polymer.

Formation of the pressure-sensitive adhesive layer on the polarizing plate is, for example, by dissolving or dispersing the pressure-sensitive adhesive composition in an organic solvent such as toluene or ethyl acetate to produce a liquid having a solid content concentration of 10 to 40% by weight, which is directly coated on the polarizing plate to form the pressure-sensitive adhesive layer. It can be performed by the method of forming an adhesive layer, the method of forming an adhesive layer by forming an adhesive layer in advance on a separate film, and sticking it on a polarizing plate. Although the thickness of an adhesive layer is determined according to the adhesive force etc., the range of about 1-50 micrometers is suitable.

Moreover, the filler, a pigment, a coloring agent, antioxidant, an ultraviolet absorber, etc. which consist of glass fiber, glass beads, resin beads, metal powder, another inorganic powder, etc. may be mix | blended with the adhesion layer as needed. Although it does not specifically limit as a ultraviolet absorber, A salicylic acid ester type compound, a benzophenone type compound, a benzotriazole type compound, a cyanoacrylate type compound, a nickel complex salt type compound, etc. are mentioned.

[Liquid crystal display device]

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

[Example]

Although an Example and a comparative example are described to the following and this invention is demonstrated to it further more concretely, this invention is not limited by these examples. In the examples,% indicating the amount to be used is based on weight unless otherwise specified.

In an Example and a comparative example, each component used for manufacture of an adhesive composition is as follows, and is represented by each symbol (brand name itself or a part thereof) below.

(A) component : epoxy compound

jER-828: Bisphenol-A epoxy resin and "jER-828" by Japan Epoxy Resin.

jER-152: A phenol novolak-type epoxy resin and "jER-152" by Japan Epoxy Resin Co., Ltd. product.

ECC: 3,4-epoxycyclohexylmethyl 3,4-epoxycyclohexanecarboxylate.

(B) Component : Oxetane Compound

OXT-211: 3-ethyl-3-phenoxymethyl oxetane, "Aron oxetane OXT-211" by Toagosei Co., Ltd. product.

OXT-221: 3-ethyl-3-[(3-ethyloxetan-3-yl) methoxymethyl] oxetane, "Aronoxetane OXT-221" manufactured by Toagosei Co., Ltd.

OXT-121: A bifunctional oxetane compound having a xylylene skeleton containing 1,4-bis [(3-ethyloxetan-3-yl) methoxymethyl] benzene as a main component, manufactured by Toagosei Co., Ltd. Aaron Oxetane OXT-121 ".

The structure of these oxetane compounds is shown below.

(C) component : photo cationic polymerization initiator

UVI-6992: The propylene carbonate solution of 50% of the active ingredient which has triarylsulfonium hexafluorophosphate as a main component, "UVI-6992" by Dow Chemical Company.

(D) component : acrylic unsaturated compound

M-203S: Tricyclodecane dimethylol diacrylate, "Aronix M-203S" by Toagosei Co., Ltd. make.

(E) component : radical photopolymerization initiator

Irg184: 1-hydroxycyclohexylphenyl ketone, "Irgacure 184" manufactured by Ciba.

(F) component : The other component which does not have a polymerizability

BR-60: Methyl methacrylate type copolymer, "Dialal BR-60" by Mitsubishi Rayon Corporation.

[Production of Adhesive Composition]

Each component shown in Table 1 and Table 2 was mix | blended in each ratio, and it stirred and mixed according to the conventional method, and manufactured the photocurable adhesive composition. In addition, since "UVI-6992" used as (C) component is a propylene carbonate solution containing 50% of an active ingredient, (C) component and propylene carbonate were divided and displayed in the table | surface. That is, the compounding quantity of "UVI-6992" in a table | surface means the ratio of solid content, and the compounding quantity of "UVI-6992" itself is 6% of the quantity shown in the column of (C) component, and the quantity shown in the column of propylene carbonate. .

[Production of Polarizing Plate 1]

Here, the following 2 types of films were used as a protective film.

Stretched norbornene-based resin film: Thickness 70 µm, trade name "ZEONOR film", manufactured by Nihon Xeon Co., Ltd. After corona discharge treatment was performed on this film, it used for bonding with a polarizer.

Biaxially stretched polyethylene terephthalate film: 50 micrometers in thickness, brand name "E5001", Toyo Boseki Co., Ltd. product. This film was also subjected to corona discharge treatment and then used for bonding with a polarizer.

On the corona discharge treatment surface of the said stretched norbornene-type resin film, the adhesive composition prepared above was coated by 3 micrometers thickness with the bar coater, and the polarizer which iodine adsorbs and orientates polyvinyl alcohol was bonded thereon. Separately, the same adhesive was also applied to the biaxially stretched polyethylene terephthalate film with a bar coater at a thickness of 3 μm, and the norbornene-based resin film of the polarizer bonded to the norbornene-based resin film was bonded to the opposite side. In this way, the ultraviolet-ray irradiation apparatus which has a belt conveyor to the polarizer by which the protective film was bonded on both surfaces (the lamp uses "Fusion H valve made by Fusion Corporation"), and irradiates an ultraviolet-ray with the accumulated light quantity 300mJ / cm <^2> from one surface. 1 hour at room temperature, the protective film which consists of a polyethylene terephthalate film was bonded to one side, and the polarizing plate 1 by which the stretched norbornene-type resin film was bonded to the other side was produced.

[Production of Polarizing Plate 2]

The biaxially stretched polyethylene terephthalate film was changed to an acrylic resin film (thickness 80 µm, trade name "Technoloid S001", manufactured by Sumitomo Chemical Co., Ltd.), and else on the one side in the same manner as in the production of the polarizing plate 1 The protective film which consists of an acrylic resin film was bonded, and the polarizing plate 2 in which the stretched norbornene-type resin film was bonded to the other surface was produced.

[Evaluation test]

About each obtained polarizing plate, curability, adhesiveness, and durability were evaluated by the following method, and the result was shown to Table 1 and Table 2.

<Hardness>

Attempts peeling between the polarizer and the polyethylene terephthalate film or the acrylic resin film by hand, completely cured and cannot be peeled off, or even when peeled, no tackiness (adhesive due to the uncured adhesive) remains on the part. (Circle) ", it peeled and the thing which tagness remained in the part was evaluated as" x ".

<Adhesiveness>

When the blade of the cutter knife was inserted at an angle from the polyethylene terephthalate film or the acrylic resin film at an angle, the film was peeled off from the polarizer and the blade entered between the polyethylene terephthalate film or the acrylic resin film and the polarizer as the worst "x". It was. When not peeling by this test, the next evaluation was further performed. That is, the polarizing plate is cut into a rectangle of 1 cm in width with the stretching direction as the long side, and shallowly indented with a cutter knife in the direction perpendicular to the stretching direction from the surface of the polyethylene terephthalate film or the acrylic resin film, and the infeed is turned outward. The degree of peeling from the ends when the sheet was bent into a "<" shape was observed. When an edge part peeled here, peeling was attempted by hand from a peeling part, and it evaluated whether peeling advances or a film breaks | disrupts. According to the evaluation result, it judged as follows.

(Triangle | delta): Peeling of an edge part is large at the time of bending, and peeling advances easily by hand.

(Circle): Although the edge part peels 1 mm back and forth when it is bent, and when peeling is attempted by hand, a film breaks down.

(Double-circle): It hardly peels at the time of bending, and if a peeling is attempted by hand, a film will be destroyed.

<durability>

For a good sample having an adhesion of &quot; ○ &quot; or higher, a cold shock cycle test was repeated at 300 ° C for 60 minutes at -35 ° C and then for 60 minutes at + 70 ° C for 15 inches (about 38 cm) diagonally. Two sample sizes of 5 inches (about 13 cm) were carried out and evaluated as follows.

○: no appearance defect at 15 inches.

(Triangle | delta): Although there is some external appearance defect at 15 inches, there is no external appearance defect at 5 inches.

×: Appearance defects even at 5 inches.

As shown in Table 1, the polarizing plates of Examples 1-7 produced using the photocurable adhesive composition of this invention were favorable adhesiveness of a polarizer and a protective film, and the curability was also favorable. Among these, in Examples 1 to 3 using "OXT-211" having one oxetanyl group and one aromatic ring in the molecule as the oxetane compound of the component (B), the adhesion was particularly good. In Example 3 containing 18% of acrylic unsaturated compound "M-203S" having an alicyclic skeleton as the component (D), in addition to good adhesiveness, durability was also good. Further, Examples 4 to 7 (in Example 4, in combination with "OXT-121") using the oxetane compound "OXT-221" having two oxetanyl groups in the molecule and liquid at room temperature and having a molecular weight of 500 or less were adhered. Excellent balance of performance and durability. Especially, Examples 4 and 5 containing 18% of acrylic unsaturated compound "M-203S" were especially favorable in adhesiveness.

On the other hand, as shown in Table 2, the comparative examples 1 and 2 which do not contain the oxetane compound of (B) component were inadequate. In particular, Comparative Example 2 in which 43% of the acrylic unsaturated compound of the component (D) was blended had poor adhesiveness to both the polyethylene terephthalate film and the acrylic resin film. In addition, the comparative example 3 which does not contain the epoxy compound of (A) component was bad in curability and adhesiveness.

The photocurable adhesive composition of this invention is easy to harden | cure by irradiation of active energy rays, such as an ultraviolet-ray, and is useful for firmly bonding a polarizer and a protective film in a short time.

Claims (20)

Adhesive composition for bonding the protective film which consists of a transparent resin film chosen from the group which consists of a polyester resin, a polycarbonate resin, and an acrylic resin to the polarizer which consists of a polyvinyl alcohol-type resin film uniaxially stretched and the dichroic dye adsorbed and oriented. as,
(A) an epoxy compound having at least two epoxy groups in a molecule,
(B) an oxetane compound having at least one oxetanyl group in the molecule, and
(C) contains a photocationic polymerization initiator,
The weight ratio (A) / (B) of the said epoxy compound (A) and the said oxetane compound (B) is 90/10-10/90,
The amount of said photocationic polymerization initiator (C) is 0.5 to 20 weight% in a composition, The photocurable adhesive composition characterized by the above-mentioned. The photocurable adhesive composition of Claim 1 in which an epoxy compound (A) contains the compound which has at least 2 epoxy groups and at least 1 aromatic ring in a molecule | numerator. The photocurable adhesive composition according to claim 2, wherein the epoxy compound (A) is selected from the group consisting of glycidyl ethers and glycidyl esters of aromatic compounds. The photocurable adhesive composition of Claim 1 or 2 in which an oxetane compound (B) contains the compound which has one oxetanyl group and at least 1 aromatic ring in a molecule | numerator. The photocurable adhesive composition of Claim 1 or 2 in which an oxetane compound (B) contains the compound which has two oxetanyl groups in a molecule | numerator. The compound according to claim 1, wherein the epoxy compound (A) has at least two epoxy groups in the molecule and at least one aromatic ring, or at least two epoxy groups and at least two aromatic rings in the molecule The photocurable adhesive composition which is a mixture with the compound which has an epoxy group and does not have an aromatic ring. The epoxy compound (A) consists of at least one selected from the group consisting of glycidyl ether and glycidyl ester of an aromatic compound, or a glycidyl ether compound and a glycidyl ester compound of an aromatic compound. A photocurable adhesive composition which is a mixture of at least one selected from the group with an epoxy compound (A) other than it. The compound according to claim 1 or 6, wherein the oxetane compound (B) has one oxetanyl group in the molecule and at least one aromatic ring, or has one oxetanyl group in the molecule and at least one aromatic ring. A photocurable adhesive composition which is a mixture of a compound and a compound having at least one oxetanyl group in a molecule and having no aromatic ring. The compound according to claim 1 or 6, wherein the oxetane compound (B) has at least two oxetanyl groups in the molecule, or a compound having at least two oxetanyl groups in the molecule and one oxetanyl group in the molecule. The photocurable adhesive composition which is a mixture with the compound which has. The photocurable according to any one of claims 1, 2, and 6, further comprising (D) an unsaturated compound having at least one ethylenically unsaturated bond in the composition in a proportion of 35% by weight or less. Adhesive composition. The photocurable adhesive composition of Claim 10 which contains an unsaturated compound (D) in 5 to 25weight% of a ratio in a composition. The photocurable adhesive composition according to claim 10, wherein the unsaturated compound (D) is a (meth) acrylic compound having at least one (meth) acryloyl group and at least one alicyclic skeleton or an aromatic ring skeleton in a molecule thereof. The photocurable adhesive composition of Claim 12 whose unsaturated compound (D) is di (meth) acrylate which has a tricyclodecane skeleton. The photocurable adhesive composition of Claim 10 which further contains the (E) radical photopolymerization initiator in a ratio of 10 weight% or less in a composition. The photocurable adhesive composition of Claim 1 which further contains (F) another component which does not have a polymerizability in a ratio of 10 weight% or less in a composition. The protective film which consists of a transparent resin film chosen from the group which consists of a polyester resin, a polycarbonate resin, and an acrylic resin is bonded to the polarizer which consists of a polyvinyl alcohol-type resin film uniaxially stretched and the dichroic dye adsorbed and oriented, A polarizing plate made of the polarizing plate, wherein the adhesive is formed from the photocurable adhesive composition according to claim 1. A protective film made of a transparent resin film selected from the group consisting of polyester resins, polycarbonate resins, and acrylic resins is bonded to a polarizer made of a polyvinyl alcohol-based resin film uniaxially stretched and adsorbed and oriented by a dichroic dye. As a method of manufacturing a polarizing plate,
An adhesive agent applying step of applying the photocurable adhesive composition according to claim 1 to at least one of the bonding surfaces of the polarizer and the protective film;
A bonding step of bonding the polarizer and the protective film through an adhesive layer obtained;
Curing process of curing the photocurable adhesive composition in a state in which a polarizer and a protective film are bonded through the adhesive layer
Method for producing a polarizing plate comprising a. Another optical layer is laminated | stacked on the polarizing plate of Claim 16, The optical member characterized by the above-mentioned. 19. The optical member of claim 18 wherein the other optical layer comprises a retardation plate. A liquid crystal display device comprising the optical member according to claim 18 or 19 disposed on one or both sides of a liquid crystal cell.