TWI381196B - A polarizing plate, a method for manufacturing the same, an optical film, and an image display device - Google Patents

Description

Polarizing plate, manufacturing method thereof, optical film and image display device

The present invention relates to a polarizing plate and a method of manufacturing the same. The polarizing plate can form a liquid crystal display device (LCD), an organic EL display device, a cathode ray tube (CRT), a plasma display panel (PDP), etc., alone or as an optical film laminated thereon. Image display device.

In clocks, mobile phones, personal digital assistants (PDAs), notebook computers, personal computer monitors, digital video discs (DVD) players, televisions (TVs), etc. Devices are rapidly gaining popularity in the market. The liquid crystal display device is a device that visualizes a polarization state caused by conversion of liquid crystal, and a polarizing element is used according to the display principle. In particular, in applications such as TVs, higher and higher brightness, contrast, and wider viewing angles are required, and in the case of polarizing plates, higher transmittance, degree of polarization, color reproducibility, and the like are required.

As the polarizing element, for example, an iodine-based polarizing element having a structure in which iodine is adsorbed to and diffused from polyvinyl alcohol has high transmittance and high degree of polarization, and is widely used as the most common polarizing element. In general, a polarizing plate is used for a polarizing plate in which a transparent protective film is bonded to a surface of a polarizing element by a water-based adhesive in which a polyvinyl alcohol-based material is dissolved in water (Patent Document 1 and Patent Document 2). As the transparent protective film, triethyl cellulose or the like having a high moisture permeability is used.

However, in the case of producing a polarizing plate as described above, in the case of using a water-based adhesive such as a polyvinyl alcohol-based adhesive, a drying step is necessary after bonding the polarizing element and the transparent protective film. In terms of increasing the productivity of the polarizing plate, it is not preferable to have a drying step in the manufacturing step of the polarizing plate.

In the case of using a water-based adhesive (so-called wet laminate), in order to improve the adhesion to the adhesive, if the moisture content of the polarizing element is not relatively increased (usually the moisture content of the polarizing element is about 30%), A polarizing plate having a good adhesion to a water-based adhesive was not obtained. However, the polarizing plate thus obtained has problems such as large dimensional change under high temperature or high temperature and high humidity. On the other hand, in order to suppress the above dimensional change, the moisture content of the polarizing element can be lowered or a transparent protective film having a low moisture permeability can be used. However, when such a polarizing element and a transparent protective film are bonded by using a water-based adhesive, the energy rate in the drying step is lowered or the polarizing characteristics are lowered, or the appearance is poor, and a polarizing plate which is actually useful cannot be obtained.

In addition, in particular, as represented by TV, in recent years, with the development of a large screen of an image display device, the enlargement of the polarizing plate is also in terms of productivity or cost (increased yield and unit area). Become very important. However, the polarizing plate using the above-described water-based adhesive has a problem that so-called light leakage (unevenness) becomes remarkable, and the term "light leakage" means that the polarizing plate undergoes dimensional change due to heat of the backlight, which becomes uneven, and The black display turns white in one part of the screen.

For the reasons described above, a large number of active energy ray-curable (especially ultraviolet-curable) adhesives have been used in place of water-based adhesives. For example, as an adhesive agent, an ultraviolet curable adhesive having an acrylic acid or a methacrylic monomer as a diluent in an acrylic oligomer such as epoxy acrylate, urethane acrylate or polyester acrylate has been proposed ( Patent Document 3).

The performance required for the polarizing plate becomes strict, and even in the case of using an active energy ray-curable adhesive, it is required to improve the adhesion between the polarizing element and the transparent protective film.

Patent Document 1: Japanese Patent Laid-Open No. 2006-220732

Patent Document 2: Japanese Patent Laid-Open Publication No. 2001-296427

Patent Document 3: Japanese Patent Laid-Open No. 61-246719

An object of the present invention is to provide a polarizing plate which has a good adhesion by bonding a polarizing element and a transparent protective film by an active energy ray-curable adhesive, and a method for producing the same.

Further, an object of the present invention is to provide an optical film in which the polarizing plate is laminated, and to provide an image display device such as a liquid crystal display device using the polarizing plate or the optical film.

The inventors of the present invention have conducted intensive studies in order to solve the above problems, and as a result, have found that the above object can be attained by the polarizing plate and the method for producing the same as described below, and the present invention has been completed.

That is, the present invention relates to a polarizing plate which is provided with a polarizing plate provided with a transparent protective film via an adhesive layer and an easy-adhesive layer on at least one surface of the polarizing element; the adhesive layer is contained An N-substituted amide-based monomer having a hydrocarbon group is formed as an active energy ray-curable adhesive of a curable component, and an easy-to-attach layer is formed by a polymer resin composition which is relatively The organic decane compound having any at least one functional group selected from the group consisting of an acrylonitrile group, a methacryl fluorenyl group, a vinyl group, and a fluorenyl group is contained in an amount of from 3 to 30 parts by weight based on 100 parts by weight of the polymer resin.

In the above polarizing plate, it is preferred that the polymer resin forming the easy-adhesion layer has a polyester skeleton.

In the above polarizing plate, an N-substituted amide-based monomer represented by the general formula (1):CH ₂ =C(R ¹ )-CONR ² (R ³ ) may be further used as a curable component (R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms which may have a mercapto group, an amine group or a quaternary ammonium group, and R ³ represents a hydrogen atom or a carbon number of 1 to 4. A linear or branched alkyl group, wherein R ² and R ^{3 are} simultaneously a hydrogen atom, and R ² and R ³ are bonded to form a 5-membered ring or a 6-membered ring which may contain an oxygen atom.

In the above polarizing plate, it is preferred that the active energy ray-curable adhesive is an electron beam curing type adhesive.

In the above polarizing plate, as the transparent protective film, at least one selected from the group consisting of a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, a polyester resin, and a (meth)acrylic resin can be preferably used.

Further, the present invention relates to a method for producing a polarizing plate, which is characterized in that it is a method of manufacturing a polarizing plate in which a transparent protective film is provided on at least one surface of a polarizing element via an adhesive layer and an easy-adhesion layer; The method includes the steps of: an active energy ray-curable type containing an N-substituted amide-based monomer having a hydroxyl group as a curable component, such that an easy-contact layer provided on the transparent protective film faces the polarizing element And a step of bonding the polarizing element to the transparent protective film, wherein the transparent protective film is provided with an easy-adhesion layer formed by the following polymer resin composition, the polymer resin composition being 100 parts by weight relative to 100 parts by weight The polymer resin contains 3 to 30 parts by weight of an organic decane compound having any at least one functional group selected from the group consisting of an acryloyl group, a methacryl fluorenyl group, a vinyl group and a fluorenyl group; and secondly, by irradiating an active energy ray to cause the above The step of curing the agent to form an adhesive layer.

Further, the present invention relates to an optical film characterized in that at least one of the above polarizing plates is laminated.

Furthermore, the present invention relates to an image display device characterized by using the above polarizing plate or the optical film.

In the polarizing plate of the present invention, an active energy ray-curable adhesive is used as an adhesive used for bonding the polarizing element and the transparent protective film. Since the active energy ray-curable adhesive is a solvent-free adhesive, it is possible to bond the polarizing element and the transparent protective film without performing a drying step like a water-based adhesive. Further, in the active energy ray-curable adhesive, since the adhesive layer is formed by irradiating the active energy ray, high-speed production can be achieved as compared with the aqueous adhesive.

As the active energy ray-curable adhesive used in the above polarizing plate, an electron beam curing type adhesive is preferred. The electron beam curing type adhesive has a higher productivity than the ultraviolet curing type adhesive, and an electron beam (that is, a dry laminate) is used in a curing method for bonding an adhesive for a polarizing element and a transparent protective film. The heating step, such as the ultraviolet curing method, is not required, and the productivity can be greatly improved. Further, by using an electron beam curing type adhesive, the durability of the polarizing plate can be improved as compared with the ultraviolet curing type adhesive.

On the other hand, when an active energy ray-curable adhesive is used as the adhesive for bonding the polarizing element and the transparent protective film as described above, the adhesion between the polarizing element and the transparent protective film may be insufficient. If the adhesive force is insufficient, the positioning of the polarizing plate or the like may be erroneous, and when the polarizing plate is newly formed, delamination of the polarizing element and the transparent protective film may occur. In the present invention, an easy-adhesion layer is provided between the transparent protective film and an adhesive layer formed by using an active energy ray-curable adhesive containing a hydrocarbon group-containing N-substituted amide-based monomer as a curable component. The adhesion is increased to suppress delamination during re-production. In the present invention, since the adhesive layer is formed by the above-described active energy ray-curable adhesive, in order to further improve the adhesion, the adhesive layer is also a polymer resin which becomes a matrix in the easy-adhesion layer. A specific organodecane compound is added. That is, in the present invention, among the organodecane compounds, in particular, an organodecane compound having any at least one functional group selected from the group consisting of an acryloyl group, a methacryl group, a vinyl group, and a fluorenyl group is used, thereby improving the ease of proceeding. The force of the layer.

Further, in the present invention, as described above, an N-substituted amide-based monomer having a hydrocarbon group is used as a curable component of an active energy ray-curable adhesive. The monomer is preferred in terms of adhesion and is particularly suitable for use as an electron beam curing type adhesive. For example, when a polarizing element having a low moisture content is used, and when a material having a low moisture permeability is used as a transparent protective film, the electron beam curing type adhesive exhibits good adhesion to the same, and the result is A polarizing plate having good dimensional stability is obtained.

When the above-mentioned curable component is used, since a polarizing plate having a small dimensional change can be produced, it is possible to easily cope with an increase in the size of the polarizing plate, and it is possible to suppress the production cost from the viewpoint of the yield and the number of units per unit area. . Further, since the polarizing plate obtained in the present invention has good dimensional stability, it is possible to suppress unevenness of the image display device caused by external heat of the backlight.

The polarizing plate of the present invention is provided with a transparent protective film on at least one surface of the polarizing element via an adhesive layer. An active energy ray-curable adhesive is used in forming the above-mentioned adhesive layer. The active energy ray-curable adhesive contains an N-substituted amide-based monomer having a hydroxyl group as a curable component. The hydroxyl group may have at least one substituent bonded to the nitrogen atom (N) forming the guanamine group, and may have two or more substituents. As the N-substituted guanamine-based monomer having a hydroxyl group, any of a monofunctional or a difunctional or higher functional group can be used. Further, one type of N-substituted amide type monomers having a hydroxyl group may be used, or two or more types may be used in combination.

The N-substituted amide-based monomer having a hydroxyl group also exhibits good adhesion to a polarizing element having a low moisture content or a transparent protective film using a material having a low moisture permeability. In particular, the following monomers showed good adhesion. For example, as the N-substituted guanamine-based monomer, N-hydroxyethyl (meth) acrylamide, N-(2,2-dimethoxy-1-hydroxyethyl)-(A) Acrylamide, N-methylol (meth) acrylamide, p-hydroxyphenyl (meth) acrylamide, N, N'-(1,2-dihydroxyethyl) bis (A) Base) acrylamide and the like. Among them, preferred is N-hydroxyethyl (meth) acrylamide. Further, (meth)acrylamide refers to a acrylamide group and/or a methacrylamide group. In the present invention, (methyl) has the same meaning as described above.

Further, the curable component may contain other monomers in addition to the N-substituted amide group monomer having a hydroxyl group. Examples of the other monomer which can be used as the curable component include a compound having a (meth)acryl fluorenyl group and a compound having a vinyl group. As the other monomer used as the curable component, either monofunctional or difunctional or the like can be used. These curing components may be selected from one type or two or more types in combination.

As the other monomer used as the curing component, for example, an N-substituted amide-based monomer other than the N-substituted amide-based monomer having a hydroxyl group is preferred. The N-substituted amide-based monomer is represented by the formula (1): CH ₂ =C(R ¹ )-CONR ² (R ³ ) (R ¹ represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom, or may have a linear or branched alkyl group having 1 to 4 carbon atoms of a mercapto group, an amine group or a quaternary ammonium group, and R ³ represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms, wherein R ² and R ³ , except that it is a hydrogen atom at the same time, and R ² and R ³ are bonded to each other to form a 5-membered ring or a 6-membered ring which may contain an oxygen atom. Examples of the linear or branched alkyl group having 1 to 4 carbon atoms in R ² or R ³ in the above formula (1) include a methyl group, an ethyl group, an isopropyl group, and a third butyl group. Examples of the alkyl group having an amine group include an aminomethyl group and an aminoethyl group. Further, when a combination of ² and R ³ forms a 5-membered ring or a 6-membered ring which may contain an oxygen atom, it has a nitrogen-containing heterocyclic ring. The heterocyclic ring may, for example, be a morpholine ring, a piperidine ring, a pyrrolidine ring or a piperazine ring.

Specific examples of the N-substituted amide-based monomer include N-methyl(meth)acrylamide, N,N-dimethyl(meth)acrylamide, and N,N-. Diethyl (meth) acrylamide, N-isopropyl acrylamide, N-butyl (meth) acrylamide, N-hexyl (meth) acrylamide, N-hydroxymethyl (A Base acrylamide, N-methylol-N-propane (meth) acrylamide, aminomethyl (meth) acrylamide, aminoethyl (meth) acrylamide, decyl methyl (Meth) acrylamide, decylethyl (meth) acrylamide, and the like. Further, examples of the heterocyclic ring-containing monomer having a hetero ring include N-propylene morpholine, N-propylene piperidine, N-methyl propylene piperidine, and N-propene pyrrolidine. These N-substituted amide-based monomers may be used alone or in combination of two or more.

When a N-substituted amide-based monomer having a hydroxyl group and an N-substituted amide-based monomer represented by the above formula (1) are used in combination as a curable component, durability, coatability, and adhesion are obtained. In this respect, a combination of N-hydroxyethyl acrylamide and N-propylene morpholine is preferred. Further, in the case of the combination, the ratio of N-hydroxyethyl acrylamide to the total amount of N-hydroxyethyl acrylamide and N-propylene morpholine can obtain good adhesion. In other words, it is preferably 40% by weight or more. The above ratio is more preferably 40 to 95% by weight, and still more preferably 60 to 90% by weight.

In addition, as the curable component, a monomer which can be used in combination with an N-substituted amide-based monomer having a hydroxyl group, in addition to the above components, examples of the compound having a (meth)acryl fluorenyl group include various rings. Oxygen (meth) acrylate, (meth) acrylate urethane, polyester (meth) acrylate or various (meth) acrylate monomers. Among them, it is preferred to use an epoxy (meth) acrylate, particularly a monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group.

As the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group, various monofunctional (meth) acrylates having an aromatic ring and a hydroxyl group can be used. The hydroxyl group may also exist as a substituent of the aromatic ring, but in the present invention, it is preferably an organic group (hydrocarbon group, especially a hydrocarbon group bonded to an alkyl group) bonded to an aromatic ring and a (meth) acrylate. presence.

Examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group include a reaction product of a monofunctional epoxy compound having an aromatic ring and (meth)acrylic acid. Examples of the monofunctional epoxy compound having an aromatic ring include phenyl glycidyl ether, t-butylphenyl glycidyl ether, and phenyl polyethylene glycol glycidyl ether. Specific examples of the monofunctional (meth) acrylate having an aromatic ring and a hydroxyl group include 2-hydroxy-3-phenoxypropyl (meth)acrylate and 2-hydroxyl (meth)acrylate. 3-tert-butylphenoxypropyl ester, 2-hydroxy-3-phenyl polyethylene glycol propyl (meth)acrylate, and the like.

Further, examples of the compound having a (meth) acrylonitrile group include a carboxyl group. The carboxyl group is also preferred in terms of adhesion. Examples of the carboxyl group monomer include (meth)acrylic acid, carboxyethyl (meth)acrylate, and carboxypentyl (meth)acrylate. Of these, acrylic acid is preferred.

Further, examples of the compound having a (meth)acryl fluorenyl group include methyl (meth)acrylate, ethyl (meth)acrylate, n-butyl (meth)acrylate, and (meth)acrylic acid 2- Ethylhexyl ester, isooctyl (meth)acrylate, isodecyl (meth)acrylate, lauryl (meth)acrylate, etc., alkyl (meth)acrylate having a carbon number of 1 to 12; An alkoxyalkyl (meth)acrylate monomer such as methoxyethyl acrylate or ethoxyethyl (meth)acrylate; 2-hydroxyethyl (meth)acrylate, (methyl) 2-hydroxypropyl acrylate, 4-hydroxybutyl (meth)acrylate, 6-hydroxyhexyl (meth)acrylate, 8-hydroxyoctyl (meth)acrylate, (meth)acrylic acid- a hydroxyl group-containing monomer such as 10-hydroxydecyl ester, (12-hydroxylauryl) (meth)acrylate or (4-hydroxymethylcyclohexyl)-methacrylate; maleic anhydride, methyl-butylene An acid anhydride group-containing monomer such as an acid anhydride; a caprolactone adduct of acrylic acid; a styrenesulfonic acid or allylsulfonic acid, 2-(meth)acrylamido-2-methylpropanesulfonic acid, (methyl) Acrylamide, propanesulfonic acid, sulfopropyl (meth)acrylate, (meth)acryloxynaphthalenesulfonic acid, etc. a sulfonic acid group-containing monomer; a hydroxy group-containing monomer such as 2-hydroxyethyl propylene phthalate phosphate. Further, (meth) acrylamide, maleimide, N-cyclohexyl maleimide, N-phenyl maleimide, etc.; Aminoethyl acrylate, aminopropyl (meth) acrylate, N,N-dimethylaminoethyl (meth) acrylate, tert-butylaminoethyl (meth) acrylate, (methyl) An alkylaminoalkyl (meth) acrylate monomer such as 3-(3-pyrimidinyl)propyl acrylate; N-(methyl) propylene oxymethylene butyl quinone imine or N- (Meth) propylene fluorenyl-6-oxyhexamethylene butyl quinone imine, N-(methyl) propylene fluorenyl-8-oxy octamethyl butyl quinone diamine, etc. A nitrogen-containing monomer such as an amine monomer.

As described above, as the curable component in the active energy ray-curable adhesive, an N-substituted amide-based monomer having a hydroxyl group is used, but as a monomer to be used together, the above formula (1) is preferred. ) is an N-substituted amide-based monomer. Further, in the case where an aromatic ring and a monofunctional (meth) acrylate having a hydroxyl group are used in combination as a curable component, it is preferred to set the ratio of the N-substituted amide group monomer having a hydroxyl group to 40% by weight. More preferably, it is 50% by weight or more, more preferably 60% by weight or more, still more preferably 70% by weight or more, and still more preferably 80% by weight or more.

As the curable component, a difunctional or higher curable component can be used. The difunctional or higher curable component is preferably a difunctional or higher (meth) acrylate, and particularly preferably a difunctional or higher epoxy (meth) acrylate. The difunctional or higher epoxy (meth) acrylate can be obtained by a reaction of a polyfunctional epoxy compound with (meth)acrylic acid. The polyfunctional epoxy compound can be exemplified by various epoxy compounds. Examples of the polyfunctional epoxy compound include an aromatic epoxy resin, an alicyclic epoxy resin, and an aliphatic epoxy resin.

Examples of the aromatic epoxy resin include bisphenol glycidyl ether of bisphenol A, diglycidyl ether of bisphenol F, and bisphenol epoxy resin such as bisglycidyl ether of bisphenol S; phenol novolac Varnish epoxy resin, cresol novolac epoxy resin, hydroxybenzaldehyde phenol novolac epoxy resin, such as novolac type epoxy resin; tetrahydroxyphenylmethane glycidyl ether, tetrahydroxybenzophenone shrinkage A polyfunctional epoxy resin such as glycerin ether or epoxidized polyvinyl phenol.

Examples of the alicyclic epoxy resin include a hydride of the above aromatic epoxy resin, an epoxy resin such as a cyclohexane type, a cyclohexyl methyl ester type, a cyclohexyl methyl ether type, a spiro system or a tricyclodecane. .

The aliphatic epoxy resin may, for example, be a polyglycidyl ether of an aliphatic polyol or an alkylene oxide adduct thereof. Examples of such examples include diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, and trimethylolpropane. Glycidyl ether, diglycidyl ether of polyethylene glycol, diglycidyl ether of propylene glycol, or one or more alkylene oxides by addition of an aliphatic polyol such as ethylene glycol or propylene glycol or glycerin A polyglycidyl ether of a polyether polyol obtained by ethylene oxide or propylene oxide or the like.

The epoxy equivalent of the above epoxy resin is usually from 30 to 3,000 g/equivalent, preferably from 50 to 1,500 g/equivalent.

The above-mentioned difunctional or higher epoxy (meth) acrylate is preferably an epoxy (meth) acrylate of an aliphatic epoxy resin, and particularly preferably an epoxy of a difunctional aliphatic epoxy resin (methyl )Acrylate.

The active energy ray-curable adhesive of the present invention contains a curable component. However, in addition to the above components, an additive may be appropriately added as needed. The active energy ray-curable adhesive can be used in an electron beam curing type or an ultraviolet curing type. When the above-mentioned adhesive is used in the electron beam curing type, it is not necessary to use a photopolymerization initiator in the above-mentioned adhesive, but in the case of using an ultraviolet curing type, a photopolymerization initiator is used. The photopolymerization initiator is used in an amount of usually from 0.1 to 10 parts by weight, preferably from 0.5 to 3 parts by weight, per 100 parts by weight of the curable component.

In addition, examples of the additive include a sensitizer which is represented by a carbonyl compound or the like, and a sensitizer which improves the curing speed or sensitivity by an electron beam, and a further accelerator which is represented by a decane coupling agent or ethylene oxide. An additive for improving the mechanical strength or processability, such as an acryl-based compound or a hydrocarbon (natural, synthetic resin), an ultraviolet absorbing agent, an anti-aging agent, a dye, and a processing aid , ion trapping agents, antioxidants, tackifiers, fillers (excluding metal compound fillers), plasticizers, leveling agents, foaming inhibitors, antistatic agents, and the like.

The polarizing plate of the present invention is provided with a polarizing element and a transparent protective film via an adhesive layer, but has an easy-adhesion layer between the transparent protective film and the adhesive layer. The easy-adhesion layer is formed by a polymer resin composition containing an organodecane compound having at least one functional group selected from the group consisting of an acryloyl group, a methacryl group, a vinyl group, and a fluorenyl group, and a polymer resin.

As the polymer resin forming the easy-adhesion layer, for example, a polyester skeleton, a polyether skeleton, a polycarbonate skeleton, a polyurethane skeleton, an anthrone, a polyamine skeleton, a polyimine skeleton, a polyvinyl alcohol skeleton, or the like can be used. Various resins. These polymer resins may be used singly or in combination of two or more. Among them, a resin having a polyester skeleton is preferred in terms of an effect of improving the adhesion force. The form of the polymer resin may be any of a water system and a solvent system.

The organodecane compound having the above functional group may, for example, be a decane coupling agent having the above functional group. Examples of the organodecane compound having an acrylonitrile group include 3-propenyloxypropyltrimethoxydecane, 3-propenyloxypropyltriethoxydecane, and the like as a methacrylonitrile group. Examples of the organodecane compound include 3-methylpropenyloxypropyltriethoxydecane, 3-methylpropenyloxypropyltrimethoxydecane, and 3-methylpropenyloxypropane. Examples of the organic decane compound having a vinyl group, such as vinyl trimethoxy decane, 3-methyl propylene methoxy propyl methyl diethoxy decane, and the like, may be exemplified by vinyl trimethoxy decane or alkene. Examples of the propyl triethoxy decane, allyl trimethoxy decane, p-styryl trimethoxy decane, p-styryl triethoxy decane, and the like, and examples of the organic decane compound having a mercapto group and the like include, for example, 3-mercaptopropylmethyldimethoxydecane, 3-mercaptopropyltrimethoxydecane, 3-mercaptopropyltriethoxydecane, and the like.

The organodecane compound having the above functional group can be increased in adhesion by being formulated in the above polymer resin, but in order to further increase the adhesion, 3 to 30 weights are formulated with respect to 100 parts by weight of the above polymer resin (solid content). An organodecane compound having the above functional group. The compounding ratio of the organodecane compound having the above functional group is preferably from 5 to 25 parts by weight, more preferably from 7 to 15 parts by weight, per 100 parts by weight of the above polymer resin (solid content).

In addition, other additives may be added during the formation of the easy-to-adhere layer. Specifically, a stabilizer such as a tackifier, an ultraviolet absorber, an antioxidant, or a heat stabilizer can be used. Further, a methylol compound such as oxazoline, boric acid or trimethylol melamine may be blended, a compound which can be a crosslinking component such as a carbodiimide or an isocyanate compound, an organodecane compound having no such functional group, or An organic decane compound (an epoxy group-containing decane coupling agent, an amine group-containing decane coupling agent, an isocyanate group-containing decane coupling agent or the like decane coupling agent) having a functional group other than the above functional group. Further, the additive (or crosslinking component) other than the organodecane compound having the above functional group cannot sufficiently improve the adhesion even when used alone, and the additives do not interfere with the use of the organodecane compound having the above functional group. In addition, the adhesion can be further improved by using them in combination. Further, in the case of using an additive other than the organodecane compound having the above functional group, the compounding ratio is preferably 50 parts by weight or less, more preferably 1 to 40 parts by weight per 100 parts by weight of the above polymer resin. Further preferably, it is 5 to 30 parts by weight.

The easy-adhesion layer is usually provided in advance on the transparent protective film, and the easy-contact layer side of the transparent protective film and the polarizing element are bonded by an adhesive layer. The formation of the easy-adhesion layer is carried out by preparing a polymer resin composition (formation material for easy adhesion layer) containing the above polymer resin and an organic decane compound having the above functional group, and using the known material, Coating and drying on a transparent protective film. The material for forming the easy-adhesion layer is usually adjusted to a solution diluted to an appropriate concentration in consideration of the thickness after drying, the smoothness of coating, and the like. The thickness of the easy-adhesion layer after drying is preferably 0.01 to 5 μm, more preferably 0.02 to 2 μm, and further preferably 0.05 to 1 μm. Further, the easy-adhesion layer may be provided with a plurality of layers, and in this case, it is also preferable that the total thickness of the easily-adhesive layer is within the above range. Further, the transparent protective film can be stretched after the easy adhesion layer is applied onto the transparent protective film.

The polarizing element is formed of a polyvinyl alcohol-based resin. As the polarizing element, a polarizing element obtained by dyeing a polyvinyl alcohol resin film with a dichroic substance (typically iodine or a dichroic dye) and uniaxially stretching it can be used. The degree of polymerization of the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film is preferably from 100 to 5,000, more preferably from 1,400 to 4,000. When the degree of polymerization is too low, elongation fracture tends to occur when a predetermined extension is performed, and if the degree of polymerization is too high, the tension must be abnormal during stretching, and mechanical elongation may not be possible.

The polyvinyl alcohol-based resin film constituting the polarizing element can be formed by any appropriate method (for example, a casting method in which a solution obtained by dissolving a resin in water or an organic solvent, and a casting method, a casting method, or an extrusion method). The thickness of the polarizing element can be appropriately set according to the purpose or use of the LCD using the polarizing plate, and is usually about 5 to 80 μm.

As a method of producing the polarizing element, any appropriate method can be employed depending on the purpose, materials to be used, conditions, and the like. For example, a method of supplying the above polyvinyl alcohol-based resin film to a series of manufacturing steps which generally includes a step of swelling, dyeing, crosslinking, stretching, water washing, and drying may be employed. In each treatment step except the drying step, the polyvinyl alcohol-based resin film is treated by immersing it in a liquid containing the solution used in each step. The order, the number of times, and whether or not the respective treatments of swelling, dyeing, cross-linking, stretching, washing, and drying can be appropriately set depending on the purpose, materials used, and conditions. For example, several treatments may be simultaneously performed in one step, and the swelling treatment, the dyeing treatment, and the crosslinking treatment may be simultaneously performed. Further, for example, a method of performing a crosslinking treatment before and after the stretching treatment can be preferably employed. Further, for example, the water washing treatment may be performed after all the treatments, or may be performed only after the specific treatment.

The swelling step is typically carried out by immersing the polyvinyl alcohol-based resin film in a treatment bath filled with water. By this treatment, the stain or the anti-blocking agent on the surface of the polyvinyl alcohol-based resin film can be cleaned, and the unevenness of the dyeing unevenness can be prevented by swelling the polyvinyl alcohol-based resin film. Glycerin or potassium iodide may be appropriately added to the swelling bath. The temperature of the swelling bath is usually about 20 to 60 ° C, and the immersion time in the swelling bath is usually about 0.1 to 10 minutes.

The dyeing step is typically carried out by immersing the polyvinyl alcohol resin film in a treatment bath containing a dichroic material such as iodine. The solvent used in the solution of the dyeing bath is usually water, but an organic solvent compatible with water may be appropriately added. The dichroic substance is usually used in a ratio of 0.1 to 1 part by weight based on 100 parts by weight of the solvent. When iodine is used as the dichroic substance, the solution of the dyeing bath preferably further contains an auxiliary agent such as iodide. It is because it can improve the dyeing efficiency. The auxiliary agent is preferably used in an amount of from 0.02 to 20 parts by weight, more preferably from 2 to 10 parts by weight, per 100 parts by weight of the solvent. Specific examples of the iodide include potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, cesium iodide, calcium iodide, tin iodide, and iodine. Iron and so on. The temperature of the dye bath is usually about 20 to 70 ° C, and the immersion time in the dye bath is usually about 1 to 20 minutes.

The crosslinking step is typically carried out by immersing the dyed polyvinyl alcohol-based resin film in a treatment bath containing a crosslinking agent. As the crosslinking agent, any appropriate crosslinking agent can be employed. Specific examples of the crosslinking agent include boron compounds such as boric acid and borax, glyoxal, and glutaraldehyde. These may be used alone or in combination. The solvent used in the solution of the crosslinking bath is usually water, but an organic solvent compatible with water may be appropriately added. The crosslinking agent is usually used in an amount of from 1 to 10 parts by weight based on 100 parts by weight of the solvent. When the concentration of the crosslinking agent is less than 1 part by weight, sufficient optical characteristics cannot be obtained. When the concentration of the crosslinking agent exceeds 10 parts by weight, the stress generated in the film during stretching may become large, possibly causing shrinkage of the obtained polarizing plate. The solution of the crosslinking bath preferably further contains an auxiliary such as an iodide. This is because it is easy to obtain the characteristics of uniform in-plane. The concentration of the auxiliary agent is preferably from 0.05 to 15% by weight, more preferably from 0.5 to 8% by weight. Specific examples of the iodide are the same as in the case of the dyeing step. The temperature of the crosslinking bath is usually about 20 to 70 ° C, preferably 40 to 60 ° C. The immersion time in the crosslinking bath is usually from about 1 second to about 15 minutes, preferably from 5 seconds to 10 minutes.

The extension step can be carried out at any of the stages described above. Specifically, it can be carried out after the dyeing treatment, and can be carried out before the dyeing treatment, and can be carried out simultaneously with the swelling treatment, the dyeing treatment, and the crosslinking treatment, or after the crosslinking treatment. The cumulative stretching ratio of the polyvinyl alcohol-based resin film is usually 5 times or more. It is preferably 5 to 7 times, and more preferably 5 to 6.5 times. When the cumulative stretching ratio is less than 5 times, it is difficult to obtain a polarizing plate having a high degree of polarization. When the cumulative stretching ratio exceeds 7 times, the polyvinyl alcohol-based resin film may be easily broken. As a specific method of extension, any appropriate method can be employed. For example, in the case of the wet stretching method, the polyvinyl alcohol-based resin film is stretched to a predetermined magnification in a treatment bath. As the solution of the stretching bath, a solution of a compound of various metal salts, iodine, boron or zinc may be preferably used in a solvent such as water or an organic solvent (for example, ethanol).

The water washing step is typically carried out by immersing the polyvinyl alcohol-based resin film subjected to the above various treatments in a treatment bath. By using the water washing step, the residue which is not required for the polyvinyl alcohol resin film can be washed away. The water bath may be pure water or an aqueous solution of an iodide (for example, potassium iodide, sodium iodide, etc.). The concentration of the aqueous iodide solution is preferably from 0.1 to 10% by weight. Additives such as zinc sulfate and zinc chloride may also be added to the aqueous iodide solution. The temperature of the water bath is preferably from 10 to 60 ° C, and more preferably from 30 to 40 ° C. The immersion time is from 1 second to 1 minute. The washing step can be carried out only once, or as many times as necessary. When the number of times is performed several times, the kind or concentration of the additive contained in the water bath used in each treatment is appropriately adjusted. For example, the water washing step includes a step of immersing the polyvinyl alcohol-based resin film subjected to the above various treatments in a potassium iodide aqueous solution (0.1 to 10% by weight, 10 to 60 ° C) for about 1 second to 1 minute; and washing with pure water. . Further, in the water washing step, in order to improve the surface modification of the polarizing element or the drying efficiency of the polarizing element, an organic solvent (for example, ethanol or the like) compatible with water may be appropriately added.

The drying step may be carried out by any appropriate method (for example, natural drying, air drying, and heat drying). For example, the drying temperature during heating and drying is usually about 20 to 80 ° C, and the drying time is usually about 1 to 10 minutes. The polarizing element can be obtained in the above manner.

The moisture content of the polarizing element used in the present invention is preferably 20% by weight or less, more preferably 0 to 15% by weight, still more preferably 1 to 15% by weight. When the moisture content is more than 20% by weight, the dimensional change of the obtained polarizing plate becomes large, and there is a possibility that the dimensional change at high temperature or high temperature and high humidity becomes large.

The moisture content of the polarizing element of the present invention can be adjusted by any appropriate method. For example, a method of controlling by the conditions of the drying step in the manufacturing step of adjusting the polarizing element can be mentioned.

The moisture content of the polarizing element was measured by the following method. That is, the polarizing element was cut into a size of 100 × 100 mm, and the initial weight of the sample was measured. Next, the sample was dried at 120 ° C for 2 hours, and the dry weight was measured, and the water content was measured by the following formula. Moisture content (% by weight) = {(initial weight - dry weight) / initial weight} x 100. The weight was measured three times and the average value was used.

The material constituting the transparent protective film is preferably a thermoplastic resin excellent in transparency, mechanical strength, thermal stability, moisture barrier properties, isotropy and the like. Specific examples of such a thermoplastic resin include cellulose resins such as triethylene fluorene cellulose, polyethylene terephthalate, polyethylene butyrate, and polyethylene naphthalate. Polyester resin, polyether oxime resin, polyfluorene resin, polycarbonate resin, polyamide resin, polyimide resin, polyolefin resin, (meth)acrylic resin, cyclic polyolefin resin (norbornene) Resin), polyarylate resin, polystyrene resin, polyvinyl alcohol resin, and mixtures thereof. Further, a transparent protective film is bonded to one side of the polarizing element by an adhesive layer, and on the other side, (meth)acrylic, urethane-based, urethane-based, epoxy can be used. A thermosetting resin such as a fluorenone or an ultraviolet curable resin is used as a transparent protective film. One or more optional additives may be contained in the transparent protective film. Examples of the additive include an ultraviolet absorber, an antioxidant, a lubricant, a plasticizer, a mold release agent, a coloring preventive agent, a flame retardant, a nucleating agent, an antistatic agent, a pigment, a colorant, and the like. The content of the above thermoplastic resin in the transparent protective film is preferably from 50 to 100% by weight, more preferably from 50 to 99% by weight, still more preferably from 60 to 98% by weight, particularly preferably from 70 to 97% by weight. . When the content of the above thermoplastic resin in the transparent protective film is 50% by weight or less, the high transparency and the like which the thermoplastic resin originally has may not be sufficiently achieved.

Further, the transparent protective film may, for example, be a polymer film described in JP-A-2001-343529 (WO 01/37007), for example, containing (A) having a substitution and/or an unsubstituted in a side chain. A bismuth imino group-based thermoplastic resin, and (B) a resin composition having a substituted and/or unsubstituted phenyl group and an eye group thermoplastic resin in a side chain. Specific examples thereof include a film containing a resin composition comprising an alternating copolymer of isobutylene and N-methylmaleimide and an acrylonitrile-styrene copolymer. As the film, a film containing a mixed extruded product of a resin composition or the like can be used. Since these films have a small phase difference and a small photoelastic coefficient, the unevenness due to the strain of the polarizing plate can be eliminated, and the moisture permeability is small, so that the film is excellent in humidifying durability.

Although the thickness of the transparent protective film can be appropriately determined, the thickness is generally about 1 to 500 μm in terms of workability such as strength and workability, and thinness. Particularly preferably, it is 1 to 300 μm, more preferably 5 to 200 μm. The transparent protective film is particularly good in the case of 5 to 150 μm.

Further, in the case where a transparent protective film is provided on both sides of the polarizing element, a protective film containing the same polymer material may be used for the inner and outer surfaces, and a protective film containing a different polymer material or the like may be used.

As the transparent protective film of the present invention, it is preferred to use at least one selected from the group consisting of a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, a polyester resin, and a (meth)acrylic resin. The adhesive for an electron beam-curable polarizing plate of the present invention exhibits good adhesion to the above various transparent protective films. In particular, the adhesive for an electron beam-curable polarizing plate of the present invention exhibits good adhesion to an acrylic resin which is difficult to satisfy the adhesion.

Cellulose resins are esters of cellulose and fatty acids. Specific examples of such a cellulose ester-based resin include triacetonitrile cellulose, diacetyl cellulose, tripropylene cellulose, and dipropylene cellulose. Among them, particularly preferred is triacetyl cellulose. Triacetin cellulose has many commercially available products and is also advantageous in terms of ease of availability or cost. As an example of the commercial product of the triacetyl cellulose, the product names "UV-50", "UV-80", "SH-80", "TD-80U", and "TD" manufactured by Fujifilm Co., Ltd. are mentioned. -TAC", "UZ-TAC" or "KC Series" manufactured by KONICA. The in-plane retardation (Re) of the triacetyl cellulose is generally about 0, and the thickness direction retardation (Rth) has about ~60 nm.

Further, the cellulose resin film having a small phase difference in the thickness direction can be obtained, for example, by treating the above cellulose resin. For example, a base film such as polyethylene terephthalate coated with a solvent such as cyclopentanone or methyl ethyl ketone, polypropylene or stainless steel may be bonded to a usual cellulose film. Heating and drying (for example, at 80 to 150 ° C for about 3 to 10 minutes), and then peeling off the substrate film; applying a norbornene-based resin or (meth)acrylic resin to a usual cellulose resin film A solution obtained by dissolving in a solvent such as cyclopentanone or methyl ethyl ketone, heating and drying (for example, at 80 to 150 ° C for about 3 to 10 minutes), and then peeling off the coating film.

Further, as the cellulose resin film having a small retardation in the thickness direction, a fatty acid cellulose resin film having a controlled degree of fat substitution can be used. In the commonly used triacetyl cellulose, the degree of substitution of acetic acid is about 2.8, and it is preferred to reduce Rth by controlling the degree of substitution of acetic acid to 1.8 to 2.7. R41 can be controlled to a small value by adding a plasticizer such as dibutyl phthalate, p-toluenesulfonanilide or triethyl citrate to the cellulose-substituted resin. The amount of the plasticizer added is preferably 40 parts by weight or less, more preferably 1 to 20 parts by weight, still more preferably 1 to 15 parts by weight, per 100 parts by weight of the fatty acid cellulose-based resin.

As a specific example of the cyclic polyolefin resin, a norbornene-based resin is preferred. The cyclic olefin resin is a general term for a resin obtained by polymerizing a cyclic olefin as a polymerization unit, and for example, Japanese Patent Laid-Open No. Hei No. Hei. A resin described in Japanese Laid-Open Patent Publication No. 3-122137. Specific examples thereof include a ring-opening (co)polymer of a cyclic olefin, an addition polymer of a cyclic olefin, a copolymer of a cyclic olefin and an α-olefin such as ethylene or propylene (representatively, random copolymerization). And a graft copolymer obtained by modifying the above with an unsaturated carboxylic acid or a derivative thereof, and the like, and the like. Specific examples of the cyclic olefin include a norbornene-based monomer.

As the cyclic polyolefin resin, various products are sold. Specific examples include the product name "ZEONEX" manufactured by Japan ZEON Co., Ltd., "ZEONOR", and the product name "ARTON" manufactured by JSR Co., Ltd., and the product name "TOPAS" manufactured by TICONA Co., Ltd., and Mitsui Chemicals Co., Ltd. The product name is "APEL".

The (meth)acrylic resin preferably has a Tg (glass transition temperature) of 115 ° C or higher, more preferably 120 ° C or higher, further preferably 125 ° C or higher, and particularly preferably 130 ° C or higher. By setting the Tg to 115 ° C or more, the durability of the polarizing plate can be excellent. The upper limit of the Tg of the (meth)acrylic resin is not particularly limited, and is preferably 170 ° C or less from the viewpoint of moldability and the like. A film having an in-plane retardation (Re) and a thickness direction retardation (Rth) of substantially 0 can be obtained from a (meth)acrylic resin.

As the (meth)acrylic resin, any suitable (meth)acrylic resin can be used without departing from the effects of the present invention. For example, poly(meth)acrylate, such as polymethyl methacrylate, methyl methacrylate- (meth)acrylic copolymer, methyl methacrylate- (meth) acrylate copolymer, A Methyl acrylate-acrylate-(meth)acrylic acid copolymer, methyl (meth)acrylate-styrene copolymer (MS resin, etc.), polymer having an alicyclic hydrocarbon group (for example, methyl methacrylate - a cyclohexyl methacrylate copolymer, a methyl methacrylate-(meth)acrylic acid norbornyl ester copolymer, etc.). Preferably, a poly(meth)acrylic acid C1-6 alkyl ester such as poly(methyl) acrylate is used. More preferably, a methyl methacrylate-based resin containing methyl methacrylate as a main component (50 to 100% by weight, preferably 70 to 100% by weight) is used.

Specific examples of the (meth)acrylic resin include, for example, ACRYPET VH or ACRYPET VRL20A manufactured by Mitsubishi Rayon Co., Ltd., which is described in Japanese Patent Laid-Open Publication No. 2004-70296. A (T) (meth)acrylic resin having a ring structure of a (meth)acrylic resin obtained by intramolecular crosslinking or intramolecular cyclization.

As the (meth)acrylic resin, a (meth)acrylic resin having a lactone ring structure can also be used. This is because it has high heat resistance, high transparency, and high mechanical strength by biaxial stretching.

Examples of the (meth)acrylic resin having a lactone ring structure include JP-A-2000-230016, JP-A-2001-151814, JP-A-2002-120326, and Japan. A (meth)acrylic resin having a lactone ring structure described in JP-A-2005-146084, and the like.

The (meth)acrylic resin having a lactone ring structure preferably has a ring structure represented by the following formula (Formula 1).

In the formula, R ¹ , R ² and R ³ each independently represent a hydrogen atom or an organic residue having 1 to 20 carbon atoms. Further, the organic residue may also contain an oxygen atom.

In the structure of the (meth)acrylic resin having a lactone ring structure, the content of the lactone ring structure represented by the formula (Formula 1) is preferably from 5 to 90% by weight, more preferably from 10 to 70. The weight %, further preferably 10 to 60% by weight, particularly preferably 10 to 50% by weight. When the content of the lactone ring structure represented by the formula (Formula 1) in the structure of the (meth)acrylic resin having a lactone ring structure is less than 5% by weight, heat resistance, solvent resistance, surface hardness May become inadequate. When the content ratio of the lactone ring structure represented by the formula (Formula 1) is more than 90% by weight in the structure of the (meth)acrylic resin having a lactone ring structure, molding workability may be deficient.

The mass average molecular weight (sometimes referred to as a weight average molecular weight) of the (meth)acrylic resin having a lactone ring structure is preferably from 1,000 to 2,000,000, more preferably from 5,000 to 1,000,000, and still more preferably from 10,000 to 10,000. 500000, especially good is 50000~500000. When the mass average molecular weight deviates from the above range, it is not preferable in terms of mold processability.

The Tg of the (meth)acrylic resin having a lactone ring structure is preferably 115 ° C or higher, more preferably 120 ° C or higher, further preferably 125 ° C or higher, and particularly preferably 130 ° C or higher. Since the Tg is 115 ° C or more, for example, when it is incorporated in a polarizing plate as a transparent protective film, durability is excellent. The upper limit of the Tg of the (meth)acrylic resin having a lactone ring structure is not particularly limited, and is preferably 170 ° C or less from the viewpoint of an ester such as moldability.

The molded article obtained by the injection molding of the (meth)acrylic resin having a lactone ring structure has a higher total light transmittance as measured according to the method of ASTM-D-1003, preferably 85% or more. More preferably, it is 88% or more, and more preferably 90% or more. The total light transmittance is a standard of transparency. If the total light transmittance is less than 85%, the transparency may be lowered.

The transparent protective film is generally used in which the front phase difference is less than 40 nm and the thickness direction retardation is less than 80 nm. The front phase difference Re is represented by Re = (nx - ny) × d. The phase difference in the thickness direction is represented by Rth = (nx - nz) × d. In addition, the Nz coefficient is represented by Nz = (nx - nz) / (nx - ny). [The refractive index of the film in the slow axis direction, the forward axis direction, and the thickness direction is set to nx, ny, nz, and d (nm), respectively, to the thickness of the film. The direction of the slow axis is the direction in which the refractive index in the film plane reaches the maximum]. Further, it is preferable that the transparent protective film is not colored. It is preferred to use a protective film having a phase difference in the thickness direction of -90 nm to +75 nm. By using the protective film having a phase difference (Rth) in the thickness direction of -90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the transparent protective film can be substantially eliminated. The thickness direction retardation (Rth) is further preferably -80 nm to +60 nm, particularly preferably -70 nm to +45 nm.

On the other hand, as the transparent protective film, a phase difference plate having a front phase difference of 40 nm or more and/or a thickness direction retardation of 80 nm or more can be used. The front phase difference is usually controlled in the range of 40 to 200 nm, and the thickness direction phase difference is usually controlled in the range of 80 to 300 nm. When a phase difference plate is used as the transparent protective film, the phase difference plate functions as a transparent protective film, so that the thickness can be reduced.

Examples of the phase difference plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a phase difference plate obtained by supporting an alignment layer of a liquid crystal polymer. The thickness of the phase difference plate is not particularly limited and is usually about 20 to 150 μm.

Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, propyl cellulose, and methyl cellulose. Polycarbonate, polyarylate, polyfluorene, polyethylene terephthalate, polyethylene naphthalate, polyether oxime, polyphenylene sulfide, polyphenylene ether, polyallyl fluorene, poly Guanamine, polyimine, polyolefin, polyvinyl chloride, cellulose resin, cyclic polyolefin resin (norbornene resin) or these binary, ternary copolymers, graft copolymerization Things, mixtures, etc. These polymer materials are used as an alignment material (stretching film) by stretching or the like.

The liquid crystal polymer may, for example, be a main chain type or a side chain type polymer in which a linear atomic group (mesogen) which imparts a conjugate property to liquid crystal alignment is introduced into a main chain or a side chain of the polymer. Specific examples of the main chain type liquid crystal polymer include a polymer having a structure in which a liquid crystal nucleus is bonded to a spacer having imparting flexibility, and for example, a nematic alignment polyester liquid crystal polymer or a circle A disc type polymer or a cholesterol type polymer or the like. Specific examples of the side chain type liquid crystal polymer include a compound having a polyether siloxane, a polyacrylate, a polymethacrylate or a polymalonate as a main chain skeleton, and including a conjugation property. The spacer of the atomic group has, as a side chain, a compound containing a liquid crystal primordial portion which is a para-substituted cyclic compound unit which imparts nematic alignment. These liquid crystal polymers are subjected to a rubbing treatment on the surface of a film such as polyimide or polyvinyl alcohol formed on a glass plate, and an alignment treatment in which a ruthenium oxide is obliquely vapor-deposited. On the surface, a solution of the liquid crystalline polymer is spread and heat-treated.

The retardation plate may be, for example, a phase difference plate having a suitable phase difference for satisfying the purpose of use, such as a variety of wavelength plates or a coloring or viewing angle caused by birefringence of the liquid crystal layer, or two or more phases. The difference plate is used to control a phase difference plate or the like having optical characteristics such as a phase difference.

The phase difference plate satisfies the relationship of nx=ny>nz, nx>ny>nz, nx>ny=nz, nx>nz>ny, nz=nx>ny, nz>nx>ny, nz>nx=ny, according to Choose from a variety of uses. In addition, ny=nz includes not only the case where ny and nz are identical, but also the case where ny and nz are substantially the same.

For example, in a phase difference plate satisfying nx>ny>nz, it is preferable to use a phase difference plate in which the front phase difference satisfies 40 to 100 nm, the thickness direction phase difference satisfies 100 to 320 nm, and the Nz coefficient satisfies 1.8 to 4.5. For example, in a phase difference plate (positive type A plate) satisfying nx>ny=nz, it is preferable to use a phase difference plate whose front phase difference satisfies 100 to 200 nm. For example, in a phase difference plate (negative type A plate) satisfying nz=nx>ny, it is preferable to use a phase difference plate whose front phase difference satisfies 100 to 200 nm. For example, in a phase difference plate satisfying nx>nz>ny, it is preferable to use a phase difference plate whose front phase difference satisfies 150 to 300 nm and whose Nz coefficient satisfies 0> to 0.7. Further, as described above, for example, a phase difference plate satisfying nx=ny>nz, nz>nx>ny, or nz>nx=ny can be used.

The transparent protective film can be appropriately selected depending on the liquid crystal display device to be applied. For example, in the case of VA (Vertical Alignment, including MVA or PVA), it is preferred that at least one of the polarizing plates (unit side) has a phase difference. As a specific phase difference, a range of Re=0 to 240 nm and Rth=0 to 500 nm is preferable. If described by a three-dimensional refractive index, it is preferably nx>ny=nz, nx>ny>nz, nx>nz>ny, nx=ny>nz (single-axis, biaxial, Z-ized, negative C plate) The situation. When the polarizing plate is used above and below the liquid crystal cell, the liquid crystal cell may have a phase difference above or below the liquid crystal cell, or may have a phase difference between any of the upper and lower transparent protective films.

For example, in the case of IPS (In-Plane Switching, including FFS), any of the case where the transparent protective film of one of the polarizing plates has a phase difference and does not have a phase difference can be used. For example, in the case where there is no phase difference, it is preferable that there is no phase difference between the upper and lower sides (cell side) of the liquid crystal cell. In the case of having a phase difference, it is preferable that the liquid crystal cell has a phase difference both above and below, and either of the upper and lower sides has a phase difference (for example, the upper side is Z, the lower side is free of phase difference, or the upper side). It is the case of the A plate and the lower side is the positive C plate). In the case of a phase difference, a range of Re = -500 to 500 nm and Rth = -500 to 500 nm is preferred. If described by a three-dimensional refractive index, it is preferable that nx>ny=nz, nx>nz>ny, nz>nx=ny, nz>nx>ny (uniaxial, Z-form, positive C plate, positive A) board).

Further, the film having the phase difference described above may be bonded to the transparent protective film having no phase difference to impart the above-described function.

On the surface of the transparent protective film which is not attached to the polarizing element (the side on which the layer is not provided with the adhesion layer), it is possible to perform a hard coat layer or a reflection treatment, an anti-adhesion treatment, and a treatment for diffusion or anti-glare.

The purpose of the hard coat treatment is to prevent surface damage or the like of the polarizing plate. For example, the surface of the transparent protective film may be formed by adding an appropriate ultraviolet curable resin such as an acrylic or an anthrone. A cured film excellent in hardness, sliding properties, and the like. The purpose of performing the anti-reflection treatment is to prevent reflection of external light on the surface of the polarizing plate, which can be accomplished by forming a film based on the prior anti-reflection film or the like. Further, the purpose of performing the anti-adhesion treatment is to prevent adhesion to an adjacent layer (for example, a diffusion plate on the backlight side).

Further, the purpose of performing the anti-glare treatment is to prevent the external light from being reflected on the surface of the polarizing plate and hinder the identification of the transmitted light of the polarizing plate, and the like, for example, can be formed by the method of sandblasting or embossing. A fine uneven structure is applied to the surface of the transparent protective film by an appropriate method such as a method of blending transparent fine particles. As the fine particles contained in the formation of the fine surface uneven structure, for example, cerium oxide, aluminum oxide, titanium oxide, zirconium oxide, tin oxide, indium oxide, cadmium oxide, or cerium oxide having an average particle diameter of 0.5 to 20 μm can be used. Inorganic fine particles which may have conductivity, and may include transparent fine particles such as organic fine particles such as crosslinked or uncrosslinked polymers. When the surface fine uneven structure is formed, the amount of the fine particles used is usually from 2 to 70 parts by weight, preferably from 5 to 50 parts by weight, per 100 parts by weight of the transparent resin forming the surface fine uneven structure. The anti-glare layer may have a diffusion layer (such as a viewing angle expansion function) that diffuses the transmitted light of the polarizing plate and expands the viewing angle.

Further, the antireflection layer, the anti-adhesion layer, the diffusion layer, the antiglare layer, and the like may be provided separately from the transparent protective film as the other transparent layer, in addition to the transparent protective film itself.

The polarizing plate of the present invention is produced by laminating a transparent protective film and a polarizing element by using the above-mentioned adhesive. Further, an easy-adhesion layer is formed between the transparent protective film and the adhesive layer formed using the adhesive. The easy-adhesion layer is usually formed on the transparent protective film, and is adhered by the above-mentioned adhesive so that the easy-adhesion layer faces the polarizing element.

In the bonding step in the above manufacturing method, the step of applying the above-mentioned adhesive to the surface of the polarizing element on which the adhesive layer is formed and/or the adhesive layer of the transparent protective film is applied, and then the polarizing plate is used. a step of bonding the polarizing element and the transparent protective film to the adhesive layer; and secondly, irradiating the polarizing element and the transparent protective film which are bonded via the polarizing plate with an active energy ray (electron ray, ultraviolet ray, etc.) to form a subsequent The step of the agent layer.

The polarizing element, the transparent protective film, and the easy-adhesion layer may be subjected to surface modification treatment before the application of the above-mentioned adhesive. Specific treatments include treatment by corona treatment, plasma treatment, and saponification treatment.

The coating method of the subsequent agent can be appropriately selected depending on the viscosity of the adhesive or the thickness of the target. Examples of the coating method include a reverse coater, a gravure coater (direct, reverse or lithographic), a bar reverse coater, a roll coater, a die coater, and a bar coat. Machine, rod coater, etc. Further, the coating may be carried out by an appropriate method such as a dipping method.

The polarizing element and the transparent protective film are bonded via the adhesive applied as described above. The bonding of the polarizing element and the transparent protective film can be performed by a roll laminator or the like.

After bonding the polarizing element and the transparent protective film, an active energy ray (electron ray, ultraviolet ray, or the like) is irradiated to cure the adhesive. The irradiation direction of the active energy ray (electron ray, ultraviolet ray, etc.) can be irradiated from any appropriate direction. It is preferred to irradiate from the side of the transparent protective film. When irradiated from the side of the polarizing element, the polarizing element may be deteriorated by an active energy ray (electron rays, ultraviolet rays, or the like).

The active energy ray-curable adhesive is preferably used as an electron beam curing type. If the irradiation condition of the electron beam is a condition capable of curing the above-mentioned adhesive, any appropriate conditions can be employed. For example, the acceleration voltage of the electron beam irradiation is preferably 5 kV to 300 kV, and more preferably 10 kV to 250 kV. When the accelerating voltage is less than 5kV, the electron beam may not reach the adhesive and cause insufficient curing. If the accelerating voltage exceeds 300kV, the penetration force through the sample is too strong, and the electron beam rebounds, which may be transparent protective film or polarized light. The component caused damage. The irradiation dose is preferably 5 to 100 kGy, and more preferably 10 to 75 kGy. When the irradiation dose is less than 5 kGy, the adhesive may be insufficiently cured. If it exceeds 100 kGy, the transparent protective film or the polarizing plate may be damaged, and the mechanical strength may be lowered or yellowed, and the predetermined optical characteristics may not be obtained.

In the case of curing by ultraviolet irradiation, 0.1 to 5 parts by weight, preferably 1 to 4 parts by weight, more preferably 2 to 3 parts by weight, based on 100 parts by weight of the curable component, of the polymerization initiator is blended. . The ultraviolet irradiation condition may be any suitable condition if it is a condition capable of curing the above-mentioned adhesive. In the ultraviolet irradiation amount of accumulated light quantity is good regardless of 100 ~ 500mJ / cm ^2, further preferably 200 ~ 400mJ / cm ^2.

The thickness of the adhesive layer in the polarizing plate of the present invention obtained as described above is 0.01 to 7 μm. It is preferably 0.01 to 5 μm, more preferably 0.01 to 2 μm, and still more preferably 0.01 to 1 μm. When the thickness is less than 0.01 μm, the cohesive force of the adhesion force itself cannot be obtained, and the adhesion strength may not be obtained. If the thickness of the adhesive layer exceeds 7 μm, the polarizing plate cannot satisfy the durability.

The electron beam irradiation is usually carried out in an inert gas, and may be carried out in the atmosphere or with a small amount of introduction of oxygen as needed. Although it differs depending on the material of the transparent protective film, by appropriately introducing oxygen, oxygen barrier is generated on the surface of the transparent protective film to which the first electron beam is irradiated, and damage to the transparent protective film can be prevented, and only the adhesive can be applied. Effectively illuminate electron rays.

In the case where the above production method is carried out in a continuous production line, the production line speed differs depending on the curing time of the adhesive, but it is preferably from 1 to 500 m/min, more preferably from 5 to 300 m/min, and further preferably 10~100m/min. In the case where the line speed is too small, the productivity is insufficient, or the damage to the transparent protective film is too large, and a polarizing plate capable of endurance durability test or the like cannot be produced. When the line speed is too large, the curing of the adhesive becomes insufficient, and the desired adhesion may not be obtained.

The polarizing plate of the present invention can be used as an optical film laminated with other optical layers in actual use. The optical layer is not particularly limited, and for example, one or two or more reflective sheets or semi-transmissive sheets, phase difference plates (including 1/2 or 1/4 wavelength plates), viewing angle compensation films, and the like may be used. An optical layer in the formation of a liquid crystal display device or the like. A particularly preferred polarizing plate is a reflective polarizing plate or a semi-transmissive polarizing plate which is further formed by laminating a reflecting plate or a semi-transmissive reflecting plate on the polarizing plate of the present invention; and ellipsically polarized light is further formed by laminating a phase difference plate on the polarizing plate. a plate or a circular polarizing plate; a wide viewing angle polarizing plate formed by further laminating a viewing angle compensation film on the polarizing plate; or a polarizing plate formed by further laminating a brightness increasing film on the polarizing plate.

The reflective polarizing plate is formed by providing a reflective layer on a polarizing plate, and can be used to form a liquid crystal display device of a type that reflects incident light incident from the identification side (display side), and can omit a built-in backlight or the like. The light source has an advantage that it is easy to make the liquid crystal display device thin. The formation of the reflective polarizing plate can be carried out by a suitable method such as providing a reflective layer made of metal or the like on one side of the polarizing plate via the transparent protective layer as needed.

Specific examples of the reflective polarizing plate include a polarizing plate in which a reflective layer of a reflective metal such as aluminum or a vapor-deposited film is formed on one surface of the matte-treated transparent protective film to form a reflective layer. In addition, a reflective polarizing plate in which the transparent protective film contains fine particles to form a surface fine uneven structure and has a reflective layer having a fine uneven structure thereon may be used. The reflective layer of the fine uneven structure diffuses the incident light by diffuse reflection, thereby preventing directionality or appearance, and has the advantage of suppressing unevenness in brightness and the like. Further, the transparent protective film containing fine particles also has an advantage that the incident light and the reflected light thereof are diffused to further suppress the unevenness of light and dark. The reflection layer of the fine uneven structure reflecting the fine uneven structure on the surface of the transparent protective film can be formed by, for example, a vapor deposition method such as a vacuum deposition method, an ion plating method, or a sputtering method, or a plating method. The method of directly attaching to the surface of the transparent protective layer is performed.

Instead of directly attaching the reflecting plate to the transparent protective film of the polarizing plate, it may be used as a reflecting sheet formed by providing a reflecting layer on a suitable film based on the transparent film. In addition, since the reflective layer usually contains a metal, it is preferable to use a transparent protective film or a polarized light in order to prevent a decrease in reflectance caused by oxidation, thereby maintaining the initial reflectance for a long period of time, or avoiding an additional protective layer. A plate or the like covers the use form of the reflecting surface.

Further, the semi-transmissive polarizing plate can be obtained by forming a semi-transmissive reflective layer such as a half mirror which reflects light by a reflective layer and transmits light therein. The transflective polarizing plate is usually disposed on the back side of the liquid crystal cell, and can form a liquid crystal display device of the following type: when a liquid crystal display device or the like is used in a relatively bright environment, reflection is incident from the identification side (display side) The image is displayed by light, and in a relatively dark environment, an image is displayed using a built-in light source such as a backlight built in the back surface of the semi-transmissive polarizing plate. That is, the semi-transmissive polarizing plate is useful for forming a liquid crystal display device or the like of the following types: in a bright environment, energy of a light source such as a backlight can be saved, and in a relatively dark environment, a liquid crystal of a built-in light source can also be used. Display device.

An elliptically polarizing plate or a circularly polarizing plate which is formed by further laminating a phase difference plate on a polarizing plate will be described. When a linearly polarized light is changed to elliptically polarized light or circularly polarized light, or elliptically polarized light or circularly polarized light is changed to linearly polarized light, or a polarization direction of linearly polarized light is changed, a phase difference plate or the like can be used. In particular, as a phase difference plate that changes linearly polarized light into circularly polarized light or circularly polarized light into linearly polarized light, a so-called quarter-wave plate (also referred to as a λ/4 plate) can be used. A 1/2 wavelength plate (also known as a λ/2 plate) is commonly used to change the direction of polarization of linearly polarized light.

The elliptically polarizing plate can be effectively used for compensating (preventing) the coloring (blue or yellow) of the super twisted nematic (STN) type liquid crystal display device due to the birefringence of the liquid crystal layer, thereby performing the coloring without the above coloring. White and black display. Further, it is preferable that the polarizing plate for controlling the three-dimensional refractive index can compensate (prevent) the coloring which occurs when the screen of the liquid crystal display device is viewed obliquely. The circularly polarizing plate can be effectively used, for example, in the case of adjusting the color tone of an image of a reflective liquid crystal display device that displays an image in color, and also has a function of preventing reflection. Specific examples of the phase difference plate include polycarbonate, polyvinyl alcohol, polystyrene, polymethyl methacrylate, polypropylene, or other polyolefins, polyarylates, polyamines, and the like. A film of a suitable polymer is a birefringence film or an alignment film of a liquid crystal polymer, and a phase difference plate made of a film supporting an alignment layer of a liquid crystal polymer. The retardation plate may be, for example, a retardation plate having a suitable phase difference for satisfying the purpose of use, such as a variety of wavelength plates or a coloring or viewing angle caused by birefringence of the liquid crystal layer, or two or more layers. A phase difference plate that controls optical characteristics such as a phase difference by a phase difference plate.

Further, the elliptically polarizing plate or the reflective elliptically polarizing plate is formed by laminating a polarizing plate, a reflective polarizing plate, and a phase difference plate in an appropriate combination. The elliptically polarizing plate or the like can also be formed by sequentially laminating (reflective) polarizing plates and phase difference plates in order to form a (reflective) polarizing plate and a phase difference plate in the manufacturing process of the liquid crystal display device. In addition, as described above, an optical film such as an elliptically polarizing plate is formed in advance, and is excellent in quality stability, lamination operability, and the like, and therefore has an advantage that the manufacturing efficiency of a liquid crystal display device or the like can be improved.

The viewing angle compensation film is a film that expands the viewing angle and obscures the image when the liquid crystal display is viewed from a direction that is not inclined perpendicularly to the screen. Such a viewing angle compensation retardation plate is composed of, for example, an alignment layer supporting a liquid crystal polymer or the like on an alignment film such as a retardation film or a liquid crystal polymer or a transparent substrate. In general, a phase difference plate uses a polymer film which is uniaxially stretched in the plane direction thereof and has birefringence, whereas a phase difference plate used as a viewing angle compensation film can be biaxially extended in the surface direction thereof and has The birefringent polymer film or a biaxially stretched film such as a birefringent polymer or a tilted alignment film which is uniaxially stretched in the plane direction thereof and which also extends in the thickness direction thereof and whose refractive index in the thickness direction is controlled. Examples of the oblique alignment film include those in which the polymer film is subjected to elongation treatment and/or shrinkage treatment by a shrinkage force formed by heating after the heat shrink film is applied to the polymer film; or the liquid crystal polymer is obliquely aligned. And so on. As the raw material polymer of the phase difference plate, the same polymer as that described in the above-mentioned retardation plate can be used, and it is possible to use a purpose of preventing the color change due to the change in the recognition angle or the like, or to expand the viewing angle with good visibility. In the polymer, the above recognition angle change is based on the phase difference caused by the liquid crystal cell.

In addition, in terms of achieving a wide viewing angle with good visibility, etc., it is preferable to use an alignment layer of a liquid crystal polymer, particularly an inclined alignment layer of a disc-type liquid crystal polymer, with a triacetyl cellulose film. An optically compensated phase difference plate supported by an optically anisotropic layer.

A polarizing plate in which a polarizing plate and a brightness enhancement film are bonded together is usually used on the back side of the liquid crystal cell. The brightness-increasing film is a film which exhibits a characteristic of direct-polarized light of a predetermined polarization axis or a circularly polarized light of a predetermined direction when natural light is incident due to a backlight of a liquid crystal display device or the like, or reflection from the back side. In addition, the polarizing plate formed by laminating the brightness enhancement film and the polarizing plate allows light from a light source such as a backlight to be incident to obtain transmitted light of a predetermined polarization state, and does not cause the predetermined polarization state. The light passes through and reflects. The light reflected on the brightness enhancement film surface is again inverted by the reflection layer or the like provided on the rear side, and is again incident on the brightness enhancement film, and a part or all of the light is transmitted as a predetermined polarization state. The amount of light transmitted through the brightness enhancement film is increased, and polarized light that is hard to be absorbed is supplied to the polarizing element, thereby increasing the amount of light that can be utilized in image display or the like of the liquid crystal display, thereby improving the brightness. In other words, when the light is incident from the back side of the liquid crystal cell by the backlight or the like without using the brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizing element is substantially polarized by the polarizing element. Absorbed, unable to pass through the polarizing element. That is, although it differs depending on the characteristics of the polarizing element to be used, about 50% of the light is absorbed into the polarizing element, so that the amount of light that can be used in liquid crystal image display or the like is reduced, resulting in darkening of the image. The brightness enhancement film is repeatedly operated such that light having a polarization direction that can be absorbed by the polarizing element is not incident on the polarizing element, but such light is temporarily reflected on the brightness enhancement film, and further The reflective layer on the rear side reverses the light to cause the light to be incident on the brightness enhancement film again. Thus, the brightness enhancement film only makes the polarization direction of the light in the light reflected and inverted between the two to be polarized. Since the polarized light in the polarization direction of the element is transmitted and supplied to the polarizing element, it is possible to effectively use light such as a backlight in the display of the image of the liquid crystal display device, thereby making the screen bright.

A diffusion plate may be provided between the brightness enhancement film and the reflective layer or the like. The light in the polarized state reflected by the brightness enhancement film faces the reflection layer or the like, and the diffusing plate provided can uniformly diffuse the passing light while eliminating the polarization state to become a non-polarized state. That is, the diffusing plate restores the polarized light to the original natural light state. In the meantime, the light in the natural light state is reflected on the reflective layer or the like, reflected by the reflective layer or the like, and then again incident on the brightness enhancement film through the diffusion plate. By providing a diffusing plate between the brightness enhancement film and the reflective layer or the like to restore the polarized light to the original natural light state, the brightness of the display screen can be maintained while reducing the brightness unevenness of the display screen, thereby providing uniformity and Bright picture. It is considered that by providing the diffusing plate, the number of times of repeated reflection of the primary incident light can be appropriately increased, and the diffusing function of the diffusing plate can be used together to provide a uniform and bright display screen.

As the brightness enhancement film, for example, a multilayer film of a dielectric or a multi-layer layer of a film having different refractive index anisotropy or the like can exhibit characteristics of transmitting linearly polarized light of a predetermined polarization axis and reflecting other light. The film, the alignment film of the cholesteric liquid crystal polymer or the film supporting the alignment liquid crystal layer on the film substrate exhibits characteristics of reflecting any one of left-handed or right-handed circularly polarized light to transmit other light. A suitable film such as a film.

Therefore, the brightness enhancement film of the type that transmits the linearly polarized light of the predetermined polarization axis can suppress the absorption loss caused by the polarizing plate by causing the transmitted light to directly enter the polarizing plate in the direction coincident with the polarization axis. At the same time, the light is transmitted efficiently. On the other hand, a brightness enhancement film of a type such as a cholesteric liquid crystal layer that transmits circularly polarized light can directly cause light to be incident on the polarizing element, but it is preferable to suppress absorption loss. The phase difference plate linearly polarizes the circularly polarized light and then enters the polarizing plate. Further, by using a quarter-wave plate as the phase difference plate, circularly polarized light can be converted into linearly polarized light.

A phase difference plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region can be obtained, for example, by using a phase difference of a quarter-wave plate for a light-colored light having a wavelength of 550 nm. The layer overlaps with a phase difference layer that exhibits other phase difference characteristics, for example, a phase difference layer that functions as a 1/2 wavelength plate. Therefore, the phase difference plate disposed between the polarizing plate and the brightness enhancement film may include one or two or more layers of retardation layers.

Further, in the case of a cholesteric liquid crystal layer, by combining the reflection wavelengths to form an arrangement structure in which two or more layers are overlapped, it is possible to obtain a circularly polarized light in a wide wavelength range such as a visible light region. Transmitted circularly polarized light over a wide range of wavelengths is available.

Further, the polarizing plate may be formed of a polarizing plate and two or more optical layers, as in the above-described polarizing-separating polarizing plate. Therefore, a reflective elliptically polarizing plate or a semi-transmissive elliptically polarizing plate in which the above-described reflective polarizing plate or semi-transmissive polarizing plate and retardation plate are combined may be used.

The optical film in which the optical layer is laminated on the polarizing plate may be formed by sequentially laminating in a manufacturing process of a liquid crystal display device or the like, but the polarizing plate which has been laminated in advance to become an optical film is stable in quality or It is excellent in assembly operation and the like, and has an advantage of being able to improve the manufacturing steps of a liquid crystal display device or the like. An appropriate bonding means such as an adhesive layer can be used in the laminate. When the polarizing plate and the other optical film are continued, the optical axes can be appropriately arranged according to the target phase difference characteristics and the like.

The polarizing plate or the optical film laminated with at least one polarizing plate may be provided with an adhesive layer for adhering to other components such as a liquid crystal cell. The adhesive for forming the adhesive layer is not particularly limited, and for example, a polymer such as an acrylic polymer, an anthrone polymer, a polyester, a polyurethane, a polyamide, a polyether, a fluorine or a rubber can be appropriately selected and used. As an adhesive for the matrix polymer. It is particularly preferable to use an adhesive which is excellent in optical transparency similar to an acrylic adhesive and which exhibits appropriate wettability, cohesiveness, and adhesive properties of the adhesive, and is excellent in weather resistance and heat resistance.

Further, in addition to the above, a liquid crystal display device which prevents foaming or peeling due to moisture absorption, prevents deterioration of optical characteristics due to poor thermal expansion, or warps the liquid crystal cell, and is excellent in high quality and durability. In terms of formability and the like, an adhesive layer having a low moisture absorption rate and excellent heat resistance is preferred.

The adhesive layer may contain a resin such as a natural product or a composition, particularly a tackifying resin or a filler containing glass fibers, glass beads, metal powder, other inorganic powder, a pigment, a colorant, an antioxidant, or the like, added thereto. Additive in the adhesive layer. Further, it may be an adhesive layer containing fine particles and exhibiting light diffusibility.

When an adhesive layer is attached to one side or both sides of a polarizing plate or an optical film, it can carry out suitably. As an example, for example, about 10 to 40% by weight of a matrix polymer or a composition thereof dissolved or dispersed in a solvent containing a single substance or a mixture of a suitable solvent such as toluene or ethyl acetate is prepared. The adhesive solution is then directly attached to the polarizing plate or the optical film by a suitable expansion method such as casting or coating; or after the adhesive layer is formed on the spacer based on the above, it is transferred and The manner of sticking on a polarizing plate or an optical film.

The adhesive layer may be provided on one or both sides of the polarizing plate or the optical film as an overlapping layer of layers of different compositions or types. In addition, when disposed on both sides, an adhesive layer of different composition, type, thickness or the like may be formed inside and outside the polarizing plate or the optical film. The thickness of the adhesive layer can be appropriately determined depending on the purpose of use or the adhesion, etc., and is generally 1 to 40 μm, preferably 5 to 30 μm, particularly preferably 10 to 25 μm. When it is thinner than 1 μm, durability is deteriorated, and when it is thicker than 40 μm, floating or peeling due to foaming or the like is likely to occur, resulting in poor appearance.

For the exposed surface of the adhesive layer, in order to prevent contamination or the like before use, the spacer may be temporarily adhered to cover. Thereby, the phenomenon of contact with the adhesive layer under normal operation conditions can be prevented. As the separator, in addition to the thickness condition described above, for example, a plastic film, a rubber sheet, a paper, or a cloth may be used, such as an anthrone or a long-chain alkyl group, a fluorine-based or a molybdenum sulfide, as needed. A suitable sheet such as a non-woven fabric, a mesh, a foamed sheet or a metal foil, or a laminated body such as the above-mentioned laminated body is formed based on a suitable separator.

In order to improve the adhesion between the polarizing plate and the adhesive layer, an adhesion-promoting layer may be provided between the layers.

As a material for forming the above-mentioned adhesion-promoting layer, a binder selected from the group consisting of a polyurethane, a polyester, and a polymer having an amine group in a molecule is preferably used, and a polymer having an amine group in a molecule is particularly preferable. Since the polymer having an amine group in the molecule exhibits an interaction between an amine group in the molecule and a carboxyl group in the adhesive or an ionic interaction, good adhesion can be ensured.

Examples of the polymer having an amine group in the molecule include an amine group-containing monomer such as polyethyleneimine, polyallylamine, polyvinylamine, polyvinylpyridine, polyvinylpyrrolidone or dimethylaminoethyl acrylate. Polymers, etc.

In order to impart antistatic properties, an antistatic agent may be added to the above-mentioned adhesion-promoting layer. Examples of the antistatic agent for imparting antistatic properties include ionic surfactants, conductive polymers such as polyaniline, polythiophene, polypyrrole, and polyquinoxaline, tin oxide, cerium oxide, and oxidation. A metal oxide system such as indium or the like is preferably a conductive polymer system from the viewpoint of stability in heating and humidification in terms of optical properties, appearance, antistatic effect, and antistatic effect. Among them, a water-soluble conductive polymer such as polyaniline or polythiophene or a water-dispersible conductive polymer is particularly preferably used. When a water-soluble conductive polymer or a water-dispersible conductive polymer is used as a material for forming an antistatic layer, deterioration of the optical film substrate caused by the organic solvent can be suppressed at the time of coating.

Further, in the present invention, each layer such as a polarizing element, a transparent protective film, an optical film, or the like which forms the polarizing plate, and an adhesive layer may be, for example, a salicylate-based compound or a benzophenol-based compound. A method of treating an ultraviolet absorber such as a benzotriazole-based compound, a cyanoacrylate-based compound, or a nickel-salt compound compound to impart ultraviolet absorbing ability or the like.

The polarizing plate or the optical film of the present invention can be suitably used for formation of various devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the previous method. In other words, the liquid crystal display device can be formed by appropriately assembling a liquid crystal cell, a polarizing plate or an optical film, and a lighting system such as an illumination system added as needed, and incorporating the driving circuit or the like, in the present invention, except The polarizing plate or the optical film of the present invention is not particularly limited, and may be formed according to the conventional method. For the liquid crystal cell, any type of liquid crystal cell such as a TN type, an STN type, a π type, a VA type, or an IPS type can also be used.

A liquid crystal display device in which a polarizing plate or an optical film is disposed on one side or both sides of a liquid crystal cell, or a liquid crystal display device such as a liquid crystal display device using a backlight or a reflecting plate in an illumination system can be formed. At this time, the polarizing plate or the optical film of the present invention may be disposed on one side or both sides of the liquid crystal cell. When a polarizing plate or an optical film is provided on both sides, the same may be the same or different. Further, when forming a liquid crystal display device, one or two or more layers such as a diffusion plate, an antiglare layer, an antireflection film, a protective plate, a tantalum array, a lens array sheet, and a light diffusing plate can be disposed at appropriate positions. Suitable components such as backlights.

Next, an organic electroluminescence device (organic EL display device) will be described. In general, an organic EL display device is formed by sequentially laminating a transparent electrode, an organic light-emitting layer, and a metal electrode on a transparent substrate to form an illuminant (organic electroluminescence). Here, the organic light-emitting layer is a laminate of various organic thin films, and for example, a laminate including a hole injection layer such as a triphenylamine derivative and a light-emitting layer containing a fluorescent organic solid such as ruthenium, or the like is known. The light-emitting layer is laminated with an electron injecting layer containing an anthracene derivative or the like, or a combination of the hole injecting layer, the light-emitting layer, and the electron injecting layer.

The organic EL display device emits light by applying a voltage to a transparent electrode and a metal electrode to inject a hole and an electron into the organic light-emitting layer, and the energy generated by the recombination of the hole and the electron is generated. Fluorescent substances are excited, and the excited fluorescent substances emit light when they return to the ground state. The recombination mechanism in the middle is the same as that of the general diode, and it can be inferred that the current and the luminescence intensity show a strong nonlinearity accompanying the rectification with respect to the applied voltage.

In the organic EL display device, in order to take out the light generated in the organic light-emitting layer, at least one of the electrodes must be transparent, and a transparent electrode made of a transparent conductor such as indium tin oxide (ITO) is usually used as the anode. On the other hand, in order to facilitate the injection of electrons and improve the luminous efficiency, it is important to use a material having a small work function in the cathode, and a metal electrode such as Mg-Ag or Al-Li is usually used.

In the organic EL display device having such a configuration, the organic light-emitting layer is formed of an extremely thin film having a thickness of about 10 nm. Therefore, the organic light-emitting layer also substantially transmits light completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate and transmitted through the transparent electrode and the organic light-emitting layer and is reflected by the metal electrode is emitted to the surface side of the transparent substrate again when it is not emitted. Therefore, when it is recognized from the outside, the organic EL device The display surface is like a mirror.

In an organic EL display device including an organic electroluminescence device, a polarizing plate may be disposed on a surface side of the transparent electrode, and a phase difference plate may be disposed between the transparent electrode and the polarizing plate, and the organic electroluminescent body is borrowed. The surface of the organic light-emitting layer that emits light by application of a voltage has a transparent electrode while having a metal electrode on the back side of the organic light-emitting layer.

Since the phase difference plate and the polarizing plate have a function of causing the light reflected from the outside and reflected by the metal electrode to become polarized light, there is an effect that the mirror surface of the metal electrode cannot be recognized from the outside due to the polarizing action. In particular, when the retardation plate is formed by a quarter-wavelength plate and the angle between the polarizing plate and the polarization direction of the phase difference plate is adjusted to π/4, the mirror surface of the metal electrode can be completely shielded.

In other words, the external light incident on the organic EL display device transmits only the linearly polarized light component due to the polarizing plate. The linearly polarized light is generally converted into elliptically polarized light by a phase difference plate, especially when the phase difference plate is a quarter wave plate and the angle between the polarizing plate and the polarization direction of the phase difference plate is π/4, which becomes circular polarization. Light.

The circularly polarized light passes through the transparent substrate, the transparent electrode, and the organic film, is reflected on the metal electrode, passes through the organic film, the transparent electrode, and the transparent substrate again, and becomes linearly polarized light again on the phase difference plate. Further, since the linearly polarized light is orthogonal to the polarization direction of the polarizing plate, the polarizing plate cannot be transmitted. As a result, the mirror surface of the metal electrode can be completely shielded.

[Examples]

The embodiments of the present invention are described below, but the embodiments of the present invention are not limited thereto.

(polarizing element)

A polyvinyl alcohol film having an average degree of polymerization of 2400, a degree of saponification of 99.9 mol%, and a thickness of 75 μm was immersed in warm water of 30 ° C for 60 seconds to swell. Next, it was dyed in an iodine solution of 0.3% by weight (weight ratio: iodine/potassium iodide = 0.5/8) at 30 ° C for 1 minute while extending to 3.5 times. Then, it was immersed in a 4 wt% aqueous solution of boric acid at 65 ° C for 0.5 minutes while extending to a total stretching ratio of 6 times. After stretching, it was dried in an oven at 70 ° C for 3 minutes to obtain a polarizing element having a thickness of 26 μm. The moisture content of the polarizing element was 13.5% by weight.

(transparent protective film)

Selective use: lactone polymethyl methacrylate film (lactoneization rate 20%, thickness 30 μm, Re=0 nm, Rth=0 nm; LMMA in Table 1), norbornene resin film (Japan ZEON (Japanese) (product name: ZEONOR, thickness 40 μm; Table 1 shows ZEONOR), polyester resin film (Mitsubishi Resin Co., Ltd., trade name S100-38, thickness 38 μm; Table 1 shows S100-38), Alternatively, a cellulose resin film (manufactured by KONICA MINOLTA OPTO Co., Ltd., trade name: KC4UY, thickness: 40 μm; Table 1 shows KC4UY).

(phase difference)

The measurement of the phase difference is performed by using a phase difference meter (manufactured by Oji Scientific Instruments Co., Ltd., product name "KOBRA21-ADH") based on the principle of the parallel Nicol rotation method, and measuring the value at a wavelength of 590 nm, based on the obtained nx. The values of ny and nz and the film thickness (d) were obtained as the front phase difference Re and the thickness direction phase difference Rth and Nz. [The refractive index of the film in the slow axis direction, the forward axis direction, and the thickness direction is set to nx, ny, and nz, respectively, and d (nm) is the thickness of the film. The direction of the slow axis is set to the direction in which the refractive index in the film plane reaches the maximum].

Example 1 (adhesive: curable component)

N-hydroxyethyl acrylamide was used as an adhesive.

(Easy to form the layer)

10 parts by weight of 3-propenyloxypropyltrimethoxydecane (KBM5103, Shin-Etsu) was formulated with respect to 100 parts by weight (solids) of a polymer having a polyester skeleton (SPARFLEX SF210, manufactured by Dai-ichi Kogyo Co., Ltd.). A fluorenone (manufactured by Acetone Co., Ltd.) was used to prepare a forming material (solid content concentration: 11% by weight). The forming material was applied to one side of a transparent protective film (lactone ring polymethyl methacrylate film) using a bar coater to a thickness of 0.3 μm, dried at 150 ° C, and formed on a transparent protective film. Floor.

(made of polarizing plate)

Using a micro gravure coating machine (gravure printing roll: #300, rotation speed 140%/linear velocity), the above-mentioned adhesive was applied to the easy-adhesion layer formed on the above transparent protective film so as to have a thickness of 5 μm. A transparent protective film with an adhesive is formed. Next, the above-mentioned transparent protective film with an adhesive agent was bonded to the both surfaces of the said polarizing element by the roller machine. The electron beam is irradiated from the side (both sides) of the transparent protective film from the bonding, and a polarizing plate having a transparent protective film on both sides of the polarizing element is obtained. The line speed was set to 20 m/min, the acceleration voltage was set to 250 kV, and the irradiation dose was set to 20 kGy.

Examples 2 to 13 and Comparative Examples 1 to 19

In the first embodiment, the type of the transparent protective film, the type of the adhesive (curable component), the ratio at the time of use, the type of the polymer resin forming the easy-adhesion layer, the type of the additive, or the amount of the use are changed to the table. A polarizing plate was obtained in the same manner as in Example 1 except for the above.

Example 14 (adhesive: curable component)

As a binder, 3 parts by weight of a photopolymerization initiator (manufactured by Nippon Ciba Specialty Chemicals Co., Ltd.; trade name Irgacure 127) was added to 100 parts by weight of N-hydroxyethyl acrylamide.

(made of polarizing plate)

In the same manner as in Example 1 (formation of the easy-adhesion layer), the above-prepared adhesive was applied in a thickness of 5 μm using a micro gravure coater (gravure printing roll: #300, rotation speed: 140%/linear velocity). The cloth was formed on an easy-adhesion layer formed on a transparent protective film (lactone-polymerized polymethyl methacrylate film) to obtain a transparent protective film with an adhesive. Next, the above-mentioned transparent protective film with an adhesive agent was bonded to the both surfaces of the said polarizing element by the roller machine. The self-adhesive transparent protective film side (both sides) is irradiated with ultraviolet rays to obtain a polarizing plate having a transparent protective film on both sides of the polarizing element. The linear velocity was set to 20 m/min, and the integrated light amount on one side was set to 200 mJ/cm ² .

Comparative Example 20, 21

In the first embodiment, a polarizing plate was obtained in the same manner as in Example 1 except that the use of the polymer resin or the additive which forms the easy-adhesion layer was changed to that shown in Table 1.

[Evaluation]

The polarizing plates obtained in the examples and the comparative examples were subjected to the following evaluations. The results are shown in Table 1.

<Continue force>

The obtained polarizing plate was cut into a size of 15 mm × 150 mm as a sample. The sample was attached to a glass plate using a double-sided tape (No. 500, manufactured by Nitto Denko Corporation). On the sample (polarizing plate), an opening was previously provided between the transparent protective film and the polarizing element, and the opening was placed on a variable angle peeling tester (manufactured by Asahi Seiko Co., Ltd.), and the peel strength (N/15 mm) was measured. The measurement conditions were normal temperature (23 ° C), peel angle: 90 degrees, and peeling speed: 3000 mm/min. The values obtained by averaging the data between the 50 mm and 100 mm of the obtained measurement data are shown in Table 1.

Table 1 shows:

(adhesive)

HEAA: N-hydroxyethyl acrylamide,

ACMO: N-propylene morpholine,

<Forming material for easy adhesion layer: polymer resin>

SF210: a polymer having a polyester skeleton (SPARFLEX SF210, manufactured by Daiichi Kogyo Co., Ltd.), WLS202: a polymer having a polyether skeleton (Hydran WLS202, manufactured by Dainippon Ink and Chemicals Co., Ltd.).

<Forming material for easy adhesion layer: additive>

KBM5103: 3-propenyloxypropyltrimethoxydecane (KBM5103, manufactured by Shin-Etsu Chemical Co., Ltd.),

KBM803: 3-mercaptopropylmethyldimethoxydecane (KBM803, manufactured by Shin-Etsuke Co., Ltd.),

KBM503: 3-methacryloxypropyltriethoxydecane (KBM503, manufactured by Shin-Etsu Chemical Co., Ltd.),

KBM1003: vinyl trimethoxy decane (KBM1003, manufactured by Shin-Etsu Chemical Co., Ltd.),

MS51: methyl citrate 51 (manufactured by Fuso Pharmaceutical Co., Ltd.),

N-MAN: N-methylol acrylamide,

M-3: trimethylol melamine (CM-3, manufactured by Dainippon Ink Chemical Industry Co., Ltd.),

WS700: oxazoline (WS700, manufactured by Nippon Shokubai Chemical Co., Ltd.),

KBM403: 3-glycidoxypropyltrimethoxydecane (KBM403, manufactured by Shin-Etsu Chemical Co., Ltd.),

KBE 585: 3-ureidopropyl triethoxy decane (KBE585, manufactured by Shin-Etsuke Co., Ltd.),

KBM603: N-2-(aminoethyl)-3-aminopropyltrimethoxydecane (KBM603, manufactured by Shin-Etsu Chemical Co., Ltd.).

Claims (8)

A polarizing plate characterized in that it is attached to at least one side of a polarizing element, and is provided with a transparent protective film sequentially via an adhesive layer and an easy-to-attach layer; wherein the adhesive layer is provided by having N-having a hydroxyl group The amide-based monomer is formed as an active energy ray-curable adhesive of a curable component, and the easy-to-attach layer is formed by a polymer resin composition: relative to 100 parts by weight The polymer resin contains 3 to 30 parts by weight of an organic decane compound having any at least one functional group selected from the group consisting of an acryloyl group, a methacryl fluorenyl group, a vinyl group and a fluorenyl group. The polarizing plate of claim 1, wherein the polymer resin forming the easy-adhesion layer has a polyester skeleton. The polarizing plate of claim 1, which further comprises an N-substituted amide-based monomer represented by the formula (1):CH ₂ =C(R ¹ )-CONR ² (R ³ ) as a curable component (R ¹ Represents a hydrogen atom or a methyl group, R ² represents a hydrogen atom or a linear or branched alkyl group having 1 to 4 carbon atoms which may have a mercapto group, an amine group or a quaternary ammonium group, and R ³ represents a hydrogen atom or a carbon number of 1 to 4 a linear or branched alkyl group; wherein R ² and R ^{3 are} simultaneously a hydrogen atom, and R ² and R ³ are bonded to form a 5-membered ring or a 6-membered ring which may contain an oxygen atom) . The polarizing plate of claim 1, wherein the active energy ray-curable adhesive is an electron ray-curable adhesive. The polarizing plate of claim 1, wherein the transparent protective film is at least one selected from the group consisting of a cellulose resin, a polycarbonate resin, a cyclic polyolefin resin, a polyester resin, and a (meth)acrylic resin. A method of manufacturing a polarizing plate according to any one of claims 1 to 5, wherein the polarizing plate is attached to at least one side of the polarizing element, sequentially via an adhesive layer, and a transparent protective film is provided next to the layer; the manufacturing method includes the steps of: arranging the easy-adhesion layer provided with the transparent protective film provided with the polarizing element and the easy-adhesion layer to face the polarizing element, by containing a step of bonding a hydroxyl group N-substituted guanamine-based monomer as an active energy ray-curable adhesive for a curable component, wherein the easy-adhesion layer is formed by a polymer resin composition, and the polymer resin composition a system comprising: 3 to 30 parts by weight of an organodecane compound having any at least one functional group selected from the group consisting of an acryloyl group, a methacryl group, a vinyl group, and a fluorenyl group, with respect to 100 parts by weight of the polymer resin; The step of forming the adhesive layer by curing the adhesive by irradiating the active energy ray. An optical film characterized in that at least one sheet of the polarizing plate of claim 1 is laminated. An image display device using the polarizing plate of any one of claims 1 to 5 or the optical film of claim 7.