JP4680165B2 - Polarizing plate and image display device using the same - Google Patents

Description

  The present invention relates to a polarizing plate and an image display device using the polarizing plate.

  One of various image display apparatuses is a liquid crystal display (LCD). The LCD is a device that displays characters, images, and the like using the electro-optical characteristics of liquid crystal molecules. Usually, the LCD includes a liquid crystal cell and two polarizing plates disposed on both sides of the liquid crystal cell. The polarizing plate generally has a configuration in which a protective film is attached to both sides of a polarizer with an adhesive. Conventionally, a triacetyl cellulose (TAC) film has been widely used as the protective film. As the adhesive for the TAC film, an aqueous adhesive is preferable because the hydrophilicity of the TAC film is high. For example, a polyvinyl alcohol adhesive obtained by mixing a cross-linking agent such as melamine in an aqueous polyvinyl alcohol solution is used. The polarizing plate may be subjected to a hard coat (high hardness) treatment. The hard coat treatment is performed by forming a hard coat layer on the TAC film using a photocurable resin. The hard coat treatment is generally applied to one TAC film of the TAC films on both sides of the polarizer.

  In the conventional polarizing plate, in order to protect the polarizer from external moisture, the thickness of the hard coat layer is about several μm to 20 μm in addition to the thickness of the TAC film being 40 μm or more. It was difficult for the polarizing plate to meet the demand for thinning.

As a polarizing plate corresponding to the thinning, a polarizing plate is proposed in which a TAC film is omitted and a resin layer formed from a photopolymerizable resin is directly laminated on the polarizing plate (for example, see Patent Document 1). However, in this polarizing plate, the adhesion between the polarizer and the hard coat layer is poor, and the hard coat property of the hard coat layer is not sufficient.
JP 2005-10329 A

  Accordingly, the present invention provides a polarizing plate that can be thinned, has high adhesion between a polarizer and a hard coat layer, and has high hard coat properties for the hard coat layer, and an image display device using the same. Objective.

In order to achieve the above object, the polarizing plate of the present invention comprises:
On at least one surface of the polarizer, intervening layer formed of a thermosetting resin is laminated directly on the intermediate layer, a hard coat layer formed from the photocurable resin is laminated directly,
The polarizer includes a hydrophilic polymer;
The thermosetting resin that is the material for forming the intervening layer is a solvent-based thermosetting polyester urethane resin, a water-based thermosetting polyester urethane resin, a water-based thermosetting silanol group-containing polycarbonate urethane resin, and a water-based thermosetting carbonate urethane resin. Including at least one selected from the group consisting of:
The photocurable resin that is a material for forming the hard coat layer includes a solvent-free photocurable composition containing the components (A), (B), and (C) described in detail below.
The thickness of each layer of the intervening layer and the hard coat layer is in the range of 5 to 25 μm.
This is the configuration.

  The image display device of the present invention is an image display device equipped with a polarizing plate, wherein the polarizing plate is the polarizing plate of the present invention.

  As described above, in the polarizing plate of the present invention, the hard coat layer is laminated on the polarizer via the intervening layer. For this reason, in the polarizing plate of this invention, the adhesiveness of the said hard-coat layer and the said polarizer is high, and the hard-coat property of the said hard-coat layer is also high. Further, since the hard coat layer also functions as a protective layer, in the polarizing plate of the present invention, it is not necessary to provide a protective layer such as a thick TAC film on both sides of the polarizer as in the prior art. In addition, since the hard coat layer can be thinned, the polarizing plate of the present invention can be thinned. Therefore, it is possible to reduce the thickness of the image display device equipped with the polarizing plate of the present invention.

  In the polarizing plate of the present invention, it is preferable that the intervening layer contains an ultraviolet absorber.

In the present invention, the thermosetting resin is selected from the group consisting of a solvent-based thermosetting polyester urethane resin, a water-based thermosetting polyester urethane resin, a water-based thermosetting silanol group-containing polycarbonate urethane resin, and a water-based thermosetting carbonate urethane resin. including at least one of the resin. The “solvent type” means a type in which a resin component is dissolved or dispersed in a solvent, and the “aqueous type” means a type in which a resin component is dissolved or dispersed in water. .

In the present invention, the forming material der Ru photocurable resin of the hard coat layer, the following (A), (B), and (C) including a solventless photocurable composition containing the components.
(A) At least one of a polyfunctional acrylic monomer and a polyfunctional methacrylic monomer represented by the following general formula (I) (B) a photocurable prepolymer that is at least one of polyurethane acrylate and polyurethane methacrylate (C) photopolymerization initiation Agent

前記一般式（Ｉ）において、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５およびＲ_６は、それぞれ、独立して、水素原子、アクリロイル基またはメタクリロイル基であり、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｒ_５およびＲ_６において、少なくとも４個は、アクリロイル基またはメタクリロイル基である。 (A) the polyfunctional acrylic monomers and polyfunctional methacrylic monomer component, Ru monomer der represented by the following general formula (I).

In the general formula (I), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, an acryloyl group or a methacryloyl group, and R ₁ , R ₂ , In R ₃ , R ₄ , R ₅ and R ₆ , at least 4 are an acryloyl group or a methacryloyl group.

Further, the solventless photocurable composition preferably contains the following component (D).
(D) Reactive diluent

  In the polarizing plate of the present invention, it is preferable that the polarizer includes iodine and a polyvinyl alcohol resin.

  The manufacturing method of the polarizing plate of this invention is a manufacturing method including the process of following (A) and (B), for example. The manufacturing method may further include the following step (C). Preferred embodiments and conditions of the production method of the present invention are the same as those of the polarizing plate of the present invention. However, you may manufacture the polarizing plate of this invention by methods other than the said manufacturing method.

(A) A coating liquid containing a thermosetting resin is directly applied to at least one surface of a polarizer to form a coating film, and the coating film is heated and cured to form an intervening layer. Process.
(B) on the intermediate layer, and applying a coating fluid containing a pre-Symbol light curable resin to form a coating film, the coating film was cured by light irradiation process the a hard coat Forming a layer;
(C) The process of laminating | stacking a protective layer on the other surface of the said polarizer through an adhesive bond layer or an adhesive layer.

  The present invention will be described in detail below.

[A. Polarizing plate of the present invention]
As described above, the polarizing plate of the present invention, formed on at least one surface of the polarizer, intervening layer formed of a thermosetting resin is laminated directly on the intermediate layer, a photocurable resin The hard cord layers thus formed are directly laminated. In the present invention, the intervening layer and the hard coat layer may be formed on one side of the polarizer or on both sides of the polarizer. In the present invention, the term “directly laminated” means that the polarizer and the intervening layer are directly in contact with each other without using another layer or member such as an adhesive layer or a pressure-sensitive adhesive layer. This means that the intervening layer and the hard coat layer are laminated in direct contact with each other. In the present invention, the planar shape of the polarizing plate is, for example, a rectangle, a square, or a rectangle, but is preferably a rectangle. Therefore, in the present invention, the shape of each constituent member of the polarizer, the intervening layer, and the hard coat layer is preferably rectangular, may be square, may be rectangular, and is preferably Is a rectangle matched to the planar shape of the polarizing plate.

  The cross-sectional view of FIG. 1 shows an example of the configuration of the polarizing plate of the present invention. In addition, in the same figure, in order to make the structure of the polarizing plate of the present invention easy to understand, the size and ratio of each structural member are different from actual ones, and the other structural diagrams (FIGS. 2 to 4) are also the same. is there. As shown in the figure, in the polarizing plate 100 of this example, the intervening layer 12 is directly laminated on one surface of the polarizer 11 (the upper surface in the same figure), and on the intervening layer 12, A hard coat layer 13 is directly laminated. In the present invention, the intervening layer and the hard coat layer may have a single layer structure or a laminated structure of two or more layers.

  The cross-sectional view of FIG. 2 shows the configuration of another example of the polarizing plate of the present invention. In FIG. 2, the same parts as those in FIG. As shown in FIG. 2, in the polarizing plate 101 of this example, an intervening layer 12 is directly laminated on one surface of the polarizer 11 (the upper surface in the figure), and a hard coat is formed on the intervening layer 12. The layer 13 is directly laminated, and a protective layer 22 is laminated on the other surface (the lower surface in the figure) of the polarizer 11 via an adhesive layer 21. Although not shown, an adhesive layer can be arbitrarily provided on the protective layer 22 in order to attach the polarizing plate 101 to another member. Although not shown, a hard coat layer may be formed on the protective layer 22. In this case, the protective layer 22 is preferably thin. An adhesive layer may be further formed on the hard coat layer formed on the protective layer 22.

  The cross-sectional view of FIG. 3 shows the configuration of still another example of the polarizing plate of the present invention. 3, the same parts as those in FIG. 1 are denoted by the same reference numerals. As shown in the figure, in the polarizing plate 102 of this example, the hard coat layer 13 includes fine particles 31 and the surface of the hard coat layer 13 has an uneven structure. If the surface of the hard coat layer 13 has a concavo-convex structure, antiglare properties (antiglare properties) can be exhibited. The polarizing plate of this example is the same as the polarizing plate of FIG. 2 except for the surface uneven structure of the hard coat layer.

  The cross-sectional view of FIG. 4 shows the configuration of still another example of the polarizing plate of the present invention. 4, the same parts as those in FIG. 3 are denoted by the same reference numerals. As shown in the figure, the polarizing plate 103 of this example has a configuration in which an antireflection layer (low refractive index layer) 41 is formed on the hard coat layer 13 having a concavo-convex structure, and other configurations are as follows. This is the same as the polarizing plate shown in FIG. In the present invention, the antireflection layer may have a single layer structure or a laminated structure of two or more layers.

  The thickness of the polarizing plate of this invention is the range of 20 micrometers-250 micrometers, for example, Preferably, it is the range of 40 micrometers-200 micrometers, More preferably, it is the range of 60 micrometers-180 micrometers.

  In the polarizing plate of the present invention, the single transmittance (T) is preferably in the range of 38% to 45%, and the degree of polarization (P) is preferably 98% or more. By setting the single transmittance (T) and the degree of polarization (P) within the above ranges, in the liquid crystal display device using the polarizing plate of the present invention, a display image with a higher contrast ratio in the front direction is obtained. be able to. The single transmittance (T) is more preferably in the range of 39% to 44%, and the polarization degree (P) is more preferably 99% or more. The single transmittance (T) and the degree of polarization (P) can be obtained, for example, by the method described in Examples described later.

  In the polarizing plate of the present invention, the hue a value (single a value) is preferably −2.0 or more, and the hue b value (single b value) is preferably 4.2 or less. The most ideal value of the hue a value (single a value) and the hue b value (single b value) is 0. By setting the hue a value (single a value) and the hue b value (single b value) to values close to 0, a display image with more vivid colors can be obtained. The hue a value (single a value) and the hue b value (single b value) are determined by using a spectrophotometer (trade name “DOT-3” manufactured by Murakami Color Research Laboratory Co., Ltd.), for example. It can be measured by obtaining a value and b value in the color system.

[B. Polarizer)
As the polarizer used in the present invention, any appropriate one can be selected as long as the object of the present invention can be achieved. Examples of the polarizer include a uniaxially stretched film obtained by adsorbing a dichroic substance such as iodine or a dichroic dye on a hydrophilic polymer film, a dehydrated polyvinyl alcohol product or a dehydrochlorinated polyvinyl chloride product. And polyene-based oriented films. Examples of the hydrophilic polymer film include a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film, and an ethylene / vinyl acetate copolymer partially saponified film. In the present invention, a polarizer in which iodine is adsorbed on a polyvinyl alcohol film is preferable.

  In consideration of optical properties, the iodine content of the polarizer is, for example, in the range of 2.0 wt% to 5.0 wt%, and preferably in the range of 2.0 wt% to 4.0 wt%. is there.

  The polarizer preferably further contains at least one of potassium and boron. The potassium content of the polarizer is preferably in the range of 0.2 wt% to 1.0 wt%, more preferably in the range of 0.3 wt% to 0.9 wt%. The boron content of the polarizer is preferably in the range of 0.5 wt% to 3.0 wt%, more preferably in the range of 1.0 wt% to 2.8 wt%. When the polarizer contains potassium and boron, a polarizer (polarizing plate) having a preferable composite elastic modulus (Er) and a high degree of polarization can be obtained. For production of a polarizer containing at least one of potassium and boron, for example, a film which is a material for forming a polarizer may be immersed in a solution of at least one of potassium and boron. The solution may also serve as a solution containing iodine.

  The polyvinyl alcohol resin can be obtained, for example, by saponifying a vinyl ester polymer obtained by polymerizing a vinyl ester monomer. The saponification degree of the polyvinyl alcohol-based resin is preferably in the range of 95 mol% to 99.9 mol% in consideration of the durability of the polarizer. The average degree of polymerization of the polyvinyl alcohol resin can be appropriately selected according to the purpose, but is preferably in the range of 1200 to 3600. In addition, the said average degree of polymerization can be calculated | required according to JISK6724 (1994), for example.

  Any appropriate molding method can be adopted as a method for obtaining the polyvinyl alcohol film. A conventionally known method can be applied as the molding method.

  The polyvinyl alcohol film preferably contains at least one of a plasticizer and a surfactant. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. By using the polyhydric alcohol or the surfactant, it is possible to further improve the dyeability and stretchability of the polarizer.

  A commercially available film can also be used as it is for the polyvinyl alcohol film. Examples of commercially available polyvinyl alcohol films include the product name “Kuraray Vinylon Film” manufactured by Kuraray Co., Ltd., the product name “Tosero Vinylon Film” manufactured by Tosero Co., Ltd., and the product manufactured by Nippon Synthetic Chemical Industry Co., Ltd. Names include “Nippon Vinylon Film”.

  The thickness of the polarizer is, for example, in the range of 5 μm to 80 μm, preferably in the range of 10 μm to 40 μm, and more preferably in the range of 20 μm to 40 μm.

[C. Intervening layer)
In the present invention, the “intervening layer” is interposed between the polarizer and the hard coat layer to improve the adhesion between them. As described above, the intervening layer is formed from a thermosetting resin. The thermosetting resin, transparency is preferably one excellent in mechanical strength, may be a Solvent-based resin may be a water-based resin. The thermosetting resins are solvent-based thermoset polyester urethane resins, water-based thermosetting polyester urethane resins, water-based thermosetting silanol group-containing polycarbonate urethane resin and aqueous thermosetting carbonate urethane resin. The thermosetting resin may be used in combination with a crosslinking agent. As the thermosetting resin, a commercially available product may be used as it is, or two or more commercially available products may be mixed and used. Examples of commercially available thermosetting resins include, for example, “Neorez” series manufactured by Enomoto Kasei Co., Ltd., “Takelac” series manufactured by Mitsui Chemicals, Inc., and “Takelac” series manufactured by Toyobo Co., Ltd. Byron "series.

As described above, the intervening layer preferably contains an ultraviolet absorber. When the intervening layer contains an ultraviolet absorber, the transmittance of ultraviolet rays, which is a cause of polarizer deterioration, can be kept low. As the ultraviolet absorber, those which do not affect the performance of the polarizing plate and are excellent in ultraviolet absorbing ability are preferable. Examples of such an ultraviolet absorber include benzotriazole-based, hydroxyphenyltriazine-based, and benzophenone-based ultraviolet absorbers. Among these, from the viewpoint that the addition amount is small and coloring of the intervening layer can be minimized, if the forming material of the intervening layer is a solvent-based resin, a hydroxyphenyltriazine-based UV absorber Is particularly preferable, or a benzotriazole-based ultraviolet absorber is particularly preferable if the material for forming the intervening layer is an aqueous resin. As the ultraviolet absorber, a commercially available product may be used as it is, or two or more commercially available products may be mixed and used. Examples of commercially available ultraviolet absorbers include trade name “TINUVIN” series manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “UVINUL” series manufactured by BASF Corporation, and the like. The content of the ultraviolet absorber in the intervening layer is, for example, 0.5 to 20 parts by weight, preferably 2 to 15 parts by weight with respect to 100 parts by weight of the thermosetting resin. . The thickness of the intervening layer is in the range of 5 μm to 25 μm, and preferably in the range of 10 μm to 20 μm.

  The thermosetting resin may be appropriately diluted with a diluent solvent. The dilution solvent is not particularly limited, and various solvents can be adopted. Examples of the diluting solvent include dibutyl ether, dimethoxymethane, dimethoxyethane, diethoxyethane, propylene oxide, 1,4-dioxane, 1,3-dioxolane, 1,3,5-trioxane, tetrahydrafuran, acetone, Methyl ethyl ketone, diethyl ketone, dipropyl ketone, diisobutyl ketone, cyclopentanone, cyclohexanone, methyl cyclohexanone, ethyl formate, propyl formate, n-pentyl formate, methyl acetate, ethyl acetate, butyl acetate, methyl propionate, ethyl propionate, acetic acid n-pentyl, acetylacetone, diacetone alcohol, methyl acetoacetate, ethyl acetoacetate, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-pe Tanol, 2-methyl-2-butanol, cyclohexanol, isobutyl acetate, methyl isobutyl ketone, 2-octanone, 2-pentanone, 2-hexanone, 2-heptanone, 3-pentanone, 3-heptanone, 4-heptanone, etc. It is done. These may be used alone or in combination of two or more.

  The intervening layer is formed by coating a coating liquid containing the thermosetting resin directly on one surface of the polarizer to form a coating film, followed by a drying treatment, and then a heat treatment. Then, the coating film is formed by curing. The coating liquid may be prepared in-house by dissolving or dispersing the thermosetting resin in the diluent solvent, or a commercially available product may be used. As a coating method of the coating liquid, a coating method using an appropriate coater can be adopted as appropriate. Examples of the coater include a reverse roll coater, a forward rotation roll coater, a gravure coater, a knife coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, a fountain coater, an air doctor coater, a kiss coater, a dip coater, a bead coater, and a blade coater. Cast coater, spray coater, spin coater, extrusion coater, hot melt coater and the like. The coater is preferably a reverse roll coater, a forward rotation roll coater, a gravure coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, and a fountain coater. The coater preferably uses a coater head using a closed applicator in order to prevent a change in the concentration of the coating liquid. If it is the coating system using the said coater, an intervening layer with small thickness variation can be obtained.

  The heating temperature in the curing treatment of the coating film is appropriately determined depending on the type of the thermosetting resin and the like, and is, for example, in the range of 60 ° C to 150 ° C, and preferably in the range of 80 ° C to 130 ° C. More preferably, it is the range of 90 degreeC-110 degreeC. The heat treatment time is, for example, in the range of 0.5 minutes to 10 minutes, preferably in the range of 0.5 minutes to 5 minutes, and more preferably in the range of 0.5 minutes to 3 minutes. . Moreover, the said heat processing may serve as the drying process of arbitrary processes. Examples of the heating and drying means include an air circulation type constant temperature oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, a roll heated for temperature control, a heat pipe roll, or a metal belt. The heating method and temperature control method used are mentioned.

[D. Hard coat layer)
In the present invention, the hard coat layer is for imparting a certain hardness to the polarizer and also serves to protect the polarizer. The hard coat layer is formed from a pre-Symbol photocurable resin. That is, the coating liquid containing the resin is applied onto the intervening layer to form a coating film, the coating film is dried as necessary, and the coating film is obtained by light irradiation treatment. The hard coat layer can be formed by curing.

As described above, the resin, under Symbol of (A) ~ (C) including a solventless photocurable composition containing the components. Since the solvent-free photocurable composition does not contain a solvent, it is possible to use a polarizer made of a material that is easily eroded by the solvent. In addition, since it does not contain a solvent, the drying process can be omitted when forming the hard coat layer, the production efficiency is increased, and problems such as dimensional changes and curling due to the drying process are avoided. can do. And since it does not contain a solvent, when the hard coat layer is formed, the solvent does not volatilize and diffuse in the work environment, the health of the worker is not harmed, and the environment is not polluted. The photocurable composition preferably further contains the following component (D).

(A) At least one of a polyfunctional acrylic monomer and a polyfunctional methacrylic monomer represented by the following general formula (I) (B) a photocurable prepolymer that is at least one of polyurethane acrylate and polyurethane methacrylate (C) photopolymerization initiation Agent (D) Reactive Diluent

  In the present invention, the “polyfunctional acrylic monomer” means an acrylic monomer having two or more acryloyl groups in the molecular structure. In the present invention, “polyfunctional methacrylic monomer” means a methacrylic monomer having two or more methacryloyl groups in the molecular structure. In the present invention, the “photocurable prepolymer” means a polymer having a photoreactive functional group in the molecular structure and having 2 to 20 repeating structural units.

  In the hard coat layer, the unreacted substances of the components (A) to (C) may remain, but from the viewpoint of obtaining a hard cord layer with higher hardness, the remaining amount of the unreacted substance is small. Moderately, ideally not.

In the component (A), the polyfunctional acrylic monomer, for example, dipentaerythritol penta acrylated bets, and the like. Further, in the component (A), the polyfunctional methacrylic monomers, for example, dipentaerythritol penta meth click relay bets, and the like.

The polyfunctional acrylic monomers and polyfunctional methacrylic monomers, in its molecular structure, an acryloyl group or a methacryloyl group, a monomer represented by four to six Yusuke that before following general formula (I). By using such a methacrylic monomer and an acrylic monomer, the degree of crosslinking of the hard coat layer can be further increased, and as a result, the obtained hard coat layer can be made to have a higher hardness. Preferable examples of the monomer represented by the general formula (I) include a monomer represented by the following general formula (II).

  The weight average molecular weight (Mw) of the polyfunctional acrylic monomer and polyfunctional methacrylic monomer is preferably in the range of 250 to 800, more preferably 320, from the viewpoint of improving the surface hardness of the hard coat layer and preventing curing shrinkage. It is the range of -700, More preferably, it is the range of 400-650.

  In the present invention, the polyfunctional acrylic monomer and polyfunctional methacrylic monomer may be used alone or in combination of two or more. As the polyfunctional acrylic monomer and polyfunctional methacrylic monomer, commercially available products may be used as they are, or two or more commercially available products may be used in combination. As a commercial item containing at least one of a polyfunctional acrylic monomer and a polyfunctional methacryl monomer, for example, Toagosei Co., Ltd. trade name "Aronix" series, Shin-Nakamura Chemical Co., Ltd. trade name "NK ester" Series, Nippon Kayaku Co., Ltd. trade name “KAYARAD” series and the like.

  The photocurable prepolymer which is the component (B) is used mainly for improving the film physical properties of the hard coat layer. By using the component (A) and the component (B) in combination, the hard coat layer can be provided with appropriate flexibility, has a high surface hardness, and has excellent adhesion. Can be obtained.

The photocurable prepolymer, Ru least one Der polyurethane acrylates and polyurethane methacrylates. These prepolymers may be used alone or in combination of two or more . Po Li urethane acrylates and polyurethane methacrylates, the molecular weight is large, this crosslink density per unit area of the hard coat layer by using the is lower, it is possible to further suppress the curing shrinkage of the hard coat layer. As a result, cracks and warpage of the polarizing plate due to the curing shrinkage can be further reduced.

  As the polyurethane methacrylate and polyurethane acrylate, commercially available products may be used as they are, or two or more commercially available products may be used in combination. Examples of commercially available products containing at least one of polyurethane methacrylate and polyurethane acrylate include trade name “Shikou” series manufactured by Nippon Synthetic Chemical Industry Co., Ltd., and aliphatic urethane acrylate manufactured by Daicel Cytec Co., Ltd.

  The weight average molecular weight (Mw) of the photocurable prepolymer is preferably in the range of 250 to 5000, more preferably in the range of 300 to 4000, from the viewpoint of improving the surface hardness of the hard coat layer and preventing curing shrinkage. More preferably, it is the range of 400-3000.

  The mass ratio (A: B) between the component (A) and the component (B) is preferably in the range of 98: 2 to 50:50 from the viewpoint of surface hardness and adhesion of the hard coat layer. More preferably, it is the range of 90: 10-60: 40.

  The photopolymerization initiator that is the component (C) is not particularly limited, and examples thereof include acetophenone photopolymerization initiators, benzoin ether photopolymerization initiators, benzophenone photopolymerization initiators, and thioxanthone photopolymerization initiators. Is mentioned. The photopolymerization initiator is preferably an acetophenone-based photopolymerization initiator from the viewpoint of preventing coloring during curing and curing speed. Examples of the acetophenone photopolymerization initiator include diethoxyacetophenone, benzyldimethyl ketal, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 4- (2-hydroxy And ethoxy) phenyl- (2-hydroxy-2-propyl) ketone, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime, and the like. In this invention, a photoinitiator may be used individually by 1 type and may use 2 or more types together.

  As the photopolymerization initiator, a commercially available product may be used as it is, or two or more commercially available products may be used in combination. Examples of commercially available photopolymerization initiators include “IRGACURE” series manufactured by Ciba Specialty Chemicals. As the photopolymerization initiator, various products available from Tokyo Chemical Industry Co., Ltd. can be used.

  The amount of the component (C) is 100 parts by weight of the sum of the component (A) and the component (B) (A + B) (when the component (D) is further included, the sum of adding the component (D)) (A + B + D) is preferably in the range of 1 to 10 parts by weight, more preferably in the range of 4 to 8 parts by weight.

  It is preferable that the photocurable composition further contains a reactive diluent which is component (D). By using the reactive diluent, the hard coat layer having excellent surface uniformity can be obtained by adjusting the viscosity of the photocurable composition to a range suitable for coating.

  As the reactive diluent, for example, a 1-3 functional low functional group monomer is used. Examples of the low functional group monomer include trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,3-butanediol diacrylate, 1,3-butanediol dimethacrylate, 1,4-butanediol diacrylate, 1 , 4-butanediol dimethacrylate, 1,6-hexanediol diacrylate, 1,6-hexanediol dimethacrylate, diethylene glycol diacrylate, diethylene glycol dimethacrylate, neopentyl glycol diacrylate, neopentyl glycol dimethacrylate, 2-ethylhexyl acrylate 2-ethylhexyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropylene Acrylate, 2-hydroxypropyl methacrylate, tetrahydrofurfuryl acrylate, tetrahydrofurfuryl methacrylate, acryloyl morpholine, methacryloyl morpholine, and the like. These reactive diluents may be used alone or in combination of two or more.

  From the viewpoint of the viscosity of the photocurable composition and the surface hardness of the hard coat layer, the total ratio (A + B) of the component (A) and the component (B) and the mass ratio of the component (D) (A + B: D) is, for example, in the range of 95: 5 to 50:50, and preferably in the range of 85:15 to 65:35.

  The photocurable composition may further contain any additive. Examples of the additive include a leveling agent, a matting agent, a sensitizer, an antistatic agent, an antioxidant, a thermal polymerization inhibitor, an adhesion imparting agent, a plasticizer, and a nonreactive polymer. The amount of the additive used is, for example, in the range of more than 0 and 5 parts by weight or less with respect to 100 parts by weight of the total of the component (A) and the component (B) (A + B).

  Arbitrary appropriate methods may be employ | adopted as the method of light-curing the said photocurable composition and forming a hard-coat layer. In the photocuring method, preferably, after the photocurable composition is directly applied to the surface of the intervening layer, the surface of the photocurable composition is irradiated with at least one of ultraviolet rays and electron beams. And a method of curing the photocurable composition.

  As a method for applying the photocurable composition, a coating method using an appropriate coater may be employed as appropriate. Examples of the coater include a reverse roll coater, a forward rotation roll coater, a gravure coater, a knife coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, a fountain coater, an air doctor coater, a kiss coater, a dip coater, a bead coater, and a blade coater. Cast coater, spray coater, spin coater, extrusion coater, hot melt coater and the like. The coater is preferably a reverse roll coater, a forward rotation roll coater, a gravure coater, a rod coater, a slot die coater, a slot orifice coater, a curtain coater, and a fountain coater. The coater preferably uses a coater head using a closed applicator in order to prevent a change in the concentration of the coating liquid. If it is the coating system using the said coater, a hard-coat layer with small thickness variation can be obtained.

  For the ultraviolet irradiation, ultraviolet irradiation means is used, and the ultraviolet irradiation means includes, for example, a light source, an irradiator, a cooling device, and a power supply device.

Examples of the light source include a high-pressure mercury lamp, an ozone-less mercury lamp, a xenon lamp, a fusion lamp, and a metal halide lamp. The wavelength of the light source can be appropriately selected from the viewpoints of curing time, ultraviolet penetration depth, and the like, but is, for example, in the range of 100 nm to 400 nm, and preferably in the range of 210 nm to 380 nm. Integrated light quantity from the light source is preferably in the range from ^{50mJ / cm 2 ~1000mJ / cm 2} .

  The irradiator is used for efficiently irradiating an object with ultraviolet rays. The irradiator preferably includes a filter (for example, a heat ray cut filter) for cutting wavelengths of infrared rays and visible rays in order to reduce thermal damage to the polarizer.

  The cooling device and the power supply device are used for keeping the temperature of the light source and the entire irradiator constant and lighting the light source stably. Examples of the cooling device include an air cooling (exhaust air or reverse exhaust) system and a water cooling system.

The thickness of the hard coat layer is in the range of 5 μm to 25 μm. If the thickness of the hard coat layer is within the above range, the surface hardness can be further increased. The thickness of the hard coat layer is more preferably in the range of 10 μm to 20 μm.

  As described above, the hard coat layer may contain fine particles in order to make the surface structure an uneven structure. This is because if the surface structure of the hard coat layer is an uneven structure, antiglare properties can be imparted. Examples of the fine particles include inorganic fine particles and organic fine particles. The inorganic fine particles are not particularly limited, and examples thereof include silicon oxide fine particles, titanium oxide fine particles, aluminum oxide fine particles, zinc oxide fine particles, tin oxide fine particles, calcium carbonate fine particles, barium sulfate fine particles, talc fine particles, kaolin fine particles, calcium sulfate fine particles and the like. Can be given. The organic fine particles are not particularly limited, and examples thereof include polymethyl methacrylate acrylate resin powder (PMMA fine particles), silicone resin powder, polystyrene resin powder, polycarbonate resin powder, acrylic styrene resin powder, benzoguanamine resin powder, melamine resin powder, Examples thereof include polyolefin resin powder, polyester resin powder, polyamide resin powder, polyimide resin powder, and polyfluorinated ethylene resin powder. These inorganic fine particles and organic fine particles may be used alone or in combination of two or more.

  The shape of the fine particles is not particularly limited, and may be, for example, a bead-like substantially spherical shape or an irregular shape such as a powder. The weight average particle diameter of the fine particles is, for example, in the range of 1 to 30 μm, and preferably in the range of 2 to 20 μm. The fine particles are preferably substantially spherical, more preferably substantially spherical fine particles having an aspect ratio of 1.5 or less.

  The mixing ratio of the fine particles is not particularly limited and can be set as appropriate. The blending ratio of the fine particles is, for example, in the range of 2 to 60 parts by weight, and preferably in the range of 1 to 50 parts by weight with respect to 100 parts by weight of the hard coat layer forming material.

  From the viewpoint of preventing light scattering and interference fringes generated at the interface between the fine particles and the hard coat layer, it is preferable to reduce the refractive index difference between the fine particles and the hard coat layer. The interference fringes are a phenomenon in which reflected light of external light entering the hard coat layer exhibits a rainbow hue. Recently, three-wavelength fluorescent lamps with excellent clarity are frequently used in offices and the like, and interference fringes appear remarkably under the three-wavelength fluorescent lamps. Since the refractive index of the hard coat layer is generally in the range of 1.4 to 1.6, fine particles having a refractive index close to this refractive index range are preferred. The difference in refractive index between the fine particles and the hard coat layer is preferably less than 0.05.

  In the polarizing plate of the present invention, an antireflection layer (low refractive index layer) may be disposed on the hard coat layer. When light strikes an object, it repeats the phenomenon of reflection at the interface, absorption inside, and scattering, and passes through the back of the object. For example, when a polarizing plate is attached to an image display device, light reflection at the interface between air and a hard coat layer is one of the factors that reduce the visibility of an image. The antireflection layer reduces the surface reflection.

  In the present invention, the antireflection layer is formed of an optical thin film whose thickness and refractive index are strictly controlled. The antireflection layer exhibits an antireflection function by canceling out the reversed phases of incident light and reflected light using the interference effect of light. The wavelength region of visible light that exhibits the antireflection function is, for example, 380 to 780 nm, and the wavelength region with particularly high visibility is in the range of 450 to 650 nm, and the reflectance at 550 nm, which is the central wavelength, is minimized. Thus, it is preferable to design the antireflection layer.

  In designing the antireflection layer based on the light interference effect, as a means for improving the interference effect, for example, there is a method of increasing the refractive index difference between the antireflection layer and the hard coat layer. In general, in a multilayer antireflection layer having a structure in which two to five optical thin layers (thin films whose thickness and refractive index are strictly controlled) are laminated, a plurality of components having different refractive indexes are formed in a predetermined thickness. Thus, the degree of freedom in optical design of the antireflection layer is increased, the antireflection effect can be further improved, and the spectral reflection characteristics can be made uniform (flat) in the visible light region. Since the optical thin film requires high thickness accuracy, each layer is generally formed by a dry method such as vacuum evaporation, sputtering, or CVD.

  The multilayer antireflection layer has a two-layer structure in which a low refractive index silicon oxide layer (refractive index: about 1.45) is laminated on a high refractive index titanium oxide layer (refractive index: about 1.8). More preferably, a four-layer structure in which a silicon oxide layer is laminated on a titanium oxide layer, a titanium oxide layer is laminated on the silicon oxide layer, and a silicon oxide layer is laminated on the titanium oxide layer. belongs to. By forming these two-layer antireflection layers or four-layer antireflection layers, it is possible to uniformly reduce reflection in the visible light wavelength region (for example, a range of 380 to 780 nm).

  Further, the antireflection effect can be exhibited also by forming a single-layer optical thin film (antireflection layer) on the hard coat layer. In general, for forming the single-layer antireflection layer, for example, a wet method such as phanten coating, die coating, spin coating, spray coating, gravure coating, roll coating, or bar coating is employed.

  The material for forming the single-layer antireflection layer is, for example, a resin material such as an ultraviolet curable acrylic resin, a hybrid material in which inorganic fine particles such as colloidal silica are dispersed in the resin, tetraethoxysilane, titanium tetraethoxide, or the like. Examples include sol-gel materials using metal alkoxides. Moreover, in the said forming material, what contains a fluorine group is preferable for imparting antifouling properties to the surface. In the forming material, for reasons such as scratch resistance, a forming material having a high inorganic component content is preferable, and the sol-gel material is more preferable. The sol-gel material can be used after partial condensation.

  The antireflection layer (low refractive index layer) may contain an inorganic sol in order to improve the film strength. The inorganic sol is not particularly limited, and examples thereof include inorganic sols such as silica, alumina, and magnesium fluoride. Among these, silica sol is preferable. The blending ratio of the inorganic sol is, for example, in the range of 10 to 80 parts by weight with respect to 100 parts by weight of the total solid content of the antireflection layer forming material. The particle size of the inorganic fine particles in the inorganic sol is preferably in the range of 2 to 50 nm, and more preferably in the range of 5 to 30 nm.

The material for forming the antireflection layer preferably contains hollow spherical silicon oxide ultrafine particles. The silicon oxide ultrafine particles preferably have an average particle diameter of about 5 to 300 nm, and more preferably in the range of 10 to 200 nm. The silicon oxide ultrafine particles are hollow spheres in which cavities are formed inside the outer shell having pores, and the cavities include at least one of a solvent and a gas at the time of preparing the silicon oxide ultrafine particles. It is. Moreover, it is preferable that the precursor substance for forming the said cavity of the said silicon oxide ultrafine particle remains in the said cavity. The thickness of the outer shell is preferably in the range of about 1 to 50 nm and in the range of about 1/50 to 1/5 of the average particle diameter of the silicon oxide ultrafine particles. The outer shell is preferably formed from a plurality of coating layers. Further, in the silicon oxide ultrafine particles, it is preferable that the pores are closed and the cavity is sealed by the outer shell. This is because the porous or voids of the silicon oxide ultrafine particles are maintained in the antireflection layer, and the refractive index of the antireflection layer can be further reduced. Such a method of manufacturing the spherical silicon oxide ultrafine particles are hollow, for example, a manufacturing method of the silica fine particles as disclosed in JP 200 1 No. -233611 Patent is preferably employed.

  The temperature of drying and curing when forming the antireflection layer (low refractive index layer) is not particularly limited, and is, for example, in the range of 60 to 150 ° C, preferably in the range of 70 to 130 ° C. The drying and curing time is, for example, in the range of 1 to 30 minutes, and when considering productivity, the range of 1 to 10 minutes is preferable. Further, after the drying and curing, a high-hardness polarizing plate having an antireflection layer can be obtained by further heat treatment. The temperature of the heat treatment is not particularly limited, and is, for example, in the range of 40 to 130 ° C., preferably in the range of 50 to 100 ° C. The heat treatment time is not particularly limited, and for example, 1 minute to From the viewpoint of improving scratch resistance for 100 hours, it is more preferable to carry out for 10 hours or more. The heat treatment can be performed by a method using a hot plate, an oven, a belt furnace, or the like.

  When a polarizing plate having an antireflection layer is attached to an image display device, the antireflection layer is likely to be the outermost layer, and thus is susceptible to contamination from the external environment. Antireflection layers are more prone to contamination than mere transparent plates.For example, surface reflectance changes due to adhesion of contaminants such as fingerprints, hand dirt, sweat, and hairdressing materials, and the deposits appear white. The displayed content may be unclear. In order to prevent the adhesion of contaminants and improve the ease of removing the adhered contaminants, a contamination prevention layer formed of a fluorine group-containing silane compound or fluorine group-containing organic compound is laminated on the antireflection layer. It is preferable to do.

[E. (Protective layer)
In the present invention, the “protective layer” is formed on the surface of the polarizer opposite to the side on which the intervening layer is disposed, and is an arbitrary component, but is preferably formed. The protective layer is preferably one that is excellent in transparency, mechanical strength, thermal stability, moisture shielding properties, retardation value stability, and the like. Examples of the material for forming the protective layer include polyester resins such as polyethylene terephthalate and polyethylene naphthalate; cellulose resins such as diacetyl cellulose and TAC; acrylic resins such as polymethyl methacrylate; polystyrene, acrylonitrile butadiene styrene, and the like. Examples thereof include resins, styrene resins such as acrylonitrile / ethylene / styrene resins, styrene / maleimide copolymers and styrene / maleic anhydride copolymers; polycarbonate resins and the like. Also, polyolefin resins such as cycloolefin resins, norbornene resins, polyethylene, polypropylene, ethylene / propylene copolymers; vinyl chloride resins; amide resins such as nylon and aromatic polyamide; aromatic polyimides, polyimideamides, etc. Imide resins; sulfone resins; polyethersulfone resins; polyetheretherketone resins; polyphenylene sulfide resins; vinyl alcohol resins; vinylidene chloride resins; vinyl butyral resins; arylate resins; Resins; Epoxy resins, polymer films made of a mixture of two or more of the above resins, and the like are also examples of the protective layer forming material.

  Examples of the polymer film include polymer films described in JP-A No. 2001-343529 and International Patent Publication WO / 37007. Examples of the polymer film include (A) a thermoplastic resin having at least one of a substituted imide group and an unsubstituted imide group on the side chain, and (B) at least one of a substituted phenyl group and an unsubstituted phenyl group on the side chain. And a polymer film containing a thermoplastic resin having a nitrile group. More specifically, for example, a polymer film containing a copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer can be mentioned.

  As the material for forming the protective layer, a cellulose resin such as TAC or a norbornene resin is preferably used from the viewpoints of polarization characteristics and durability. Commercially available products of these resins include, for example, the product name “Fujitac” manufactured by Fuji Photo Film Co., Ltd., the product name “Zeonor” manufactured by Zeon Corporation, and the product name “Arton” manufactured by JSR Corporation. Or the like.

  The thickness of the protective layer can be determined as appropriate, but is, for example, in the range of 1 μm to 500 μm from the viewpoints of workability such as strength and handleability, and thinning. When the thickness of the protective layer is within the above range, the polarizer is mechanically protected, and even when exposed to high temperature and high humidity, the polarizer is prevented from contracting and stable optical characteristics can be maintained. The thickness of the protective layer is preferably in the range of 5 μm to 200 μm, more preferably in the range of 10 μm to 150 μm.

  As the protective layer, it is preferable to use a layer having an optimized retardation value. If such a protective layer is used, the viewing angle characteristics of the image display device are not affected.

  As the retardation value of the protective layer, the retardation value (Re) in the film plane is preferably in the range of 0 nm to 5 nm, more preferably in the range of 0 nm to 3 nm, and still more preferably 0 nm. The thickness direction retardation value (Rth) is preferably in the range of 0 nm to 15 nm, more preferably in the range of 0 nm to 12 nm, and still more preferably in the range of 0 nm to 5 nm. Most preferably, it is in the range of 0 nm to 3 nm.

[F. Lamination of polarizer and protective layer)
The method for laminating the polarizer and the protective layer is not particularly limited, and can be performed, for example, via an adhesive layer as shown in FIG. Examples of the adhesive include an adhesive made of an acrylic polymer or a vinyl alcohol polymer. The adhesive is preferably an adhesive made of a vinyl alcohol polymer from the viewpoint of adhesive strength with a polarizer. The adhesive may contain a water-soluble crosslinking agent of vinyl alcohol polymer such as boric acid, borax, glutaraldehyde, melamine, oxalic acid, and the like. By providing the adhesive layer, the protective layer is unlikely to peel off due to the influence of temperature and heat, and a polarizing plate with better light transmittance and degree of polarization can be obtained.

  When a polymer film containing a norbornene-based resin is used as the protective layer, it is preferable to use an adhesive that is excellent in transparency, has a small birefringence, and can exhibit a sufficient adhesive force even as a thin layer. . As such an adhesive, for example, an adhesive for dry laminate, a styrene butadiene rubber adhesive, an epoxy two-component curable adhesive (for example, an epoxy resin and an epoxy resin) mixed with a polyurethane resin solution and a polyisocyanate resin solution. A two-component polythiol or a two-component epoxy resin and polyamide) can be used, and a solvent-type adhesive and an epoxy two-component curable adhesive are particularly preferable. Some adhesives can improve the adhesive force by using an appropriate adhesive primer. When using such an adhesive, it is preferable to use the adhesive primer.

  The adhesive primer is not particularly limited as long as it can improve the adhesive force.For example, in the same molecule, a reactive functional group such as amino group, vinyl group, epoxy group, mercapto group, chloro group and the like. Silane coupling agent having hydrolyzable alkoxysilyl group, titanate coupling agent having hydrolyzable hydrophilic group and organic functional group containing titanium in the same molecule, aluminum in the same molecule Coupling agents such as aluminate-based coupling agents having a hydrolyzable hydrophilic group and an organic functional group containing; organic reactive groups such as epoxy resins, isocyanate resins, urethane resins, ester urethane resins A resin having can be used. Especially, it is preferable to use a silane coupling agent from a viewpoint that it is easy to handle industrially.

[G. Lamination of polarizing plate to liquid crystal cell)
When the polarizing plate of the present invention is used by being laminated on a liquid crystal cell, for example, an adhesive layer or a pressure-sensitive adhesive layer is preferably provided on the surface of the protective layer opposite to the polarizer side. Thereby, lamination | stacking of the polarizing plate of this invention to the said liquid crystal cell becomes easy.

  The adhesive or the pressure-sensitive adhesive is not particularly limited. For example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based Those having a base polymer of a rubber-based polymer such as natural rubber or synthetic rubber can be appropriately selected and used. In particular, an acrylic pressure-sensitive adhesive is preferably used in that it is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesiveness, and is excellent in weather resistance and heat resistance.

[I. (Use)
The polarizing plate of the present invention can be preferably used for various image display devices such as a liquid crystal display device (LCD) and an EL display (ELD). The liquid crystal display device of the present invention has the same configuration as the conventional liquid crystal display device except that the polarizing plate of the present invention is used. In the liquid crystal display device of the present invention, for example, a liquid crystal cell, an optical member such as a polarizing plate of the present invention, and various components such as an illumination system (backlight or the like) are appropriately assembled to incorporate a drive circuit. Etc. can be manufactured.

  In the present invention, the configuration of the liquid crystal display device is not particularly limited, and a liquid crystal display device in which an optical member such as a polarizing plate of the present invention is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector is used for an illumination system. Liquid crystal display devices. When optical members such as the polarizing plate of the present invention are arranged on both sides of the liquid crystal cell, they may be the same or different. Furthermore, in the liquid crystal display device of the present invention, for example, optical members and optical components such as a diffusion plate, an antiglare layer, an antireflection layer, a protective plate, a prism array, and a lens array sheet may be disposed.

  The image display device of the present invention is used for any appropriate application. Applications include, for example, OA equipment such as desktop personal computers, notebook personal computers, and copiers, mobile phones, watches, digital cameras, personal digital assistants (PDAs), portable devices such as portable game machines, video cameras, televisions, microwave ovens, etc Household electrical equipment, back monitor, car navigation system monitor, car audio and other in-vehicle equipment, display equipment for commercial store information monitors, security equipment such as monitoring monitors, nursing care monitors, medical monitors, etc. Nursing care / medical equipment.

  Examples of the present invention will be described together with comparative examples. The present invention is not limited or restricted by the following examples and comparative examples. In addition, various properties and physical properties in each example and each comparative example were measured and evaluated by the following methods.

(1) Thickness When the thickness was less than 10 μm, measurement was performed using a spectrophotometer for thin film [manufactured by Otsuka Electronics Co., Ltd., trade name “instant multiphotometry system MCPD-2000”]. When the thickness was 10 μm or more, measurement was performed using a digital micrometer manufactured by Anritsu Co., Ltd., trade name “KC-351C type”.

(2) Single transmittance of polarizing plate (T)
Using a spectrophotometer [Murakami Color Research Laboratory Co., Ltd., trade name “DOT-3”], the single transmittance (T) of the polarizing plate was determined in accordance with the 2 degree field of view defined in JlS Z 8701 (1982) ( C light source) was used to measure and obtain the Y value that had been corrected for visibility.

(3) Polarization degree of polarizing plate (P)
Polarization degree (P) of the polarizer was determined by using a spectrophotometer [Murakami Color Research Laboratory Co., Ltd., trade name “DOT-3”], parallel transmittance (H ₀ ) and orthogonal transmittance of the polarizing plate. (H ₉₀ ) was measured and determined from the formula: degree of polarization (%) = {(H ₀ −H ₉₀ ) / (H ₀ + H ₉₀ )} ^1/2 × 100. The parallel transmittance (H ₀ ) is a transmittance value of a parallel laminated polarizing plate produced by superposing two polarizing plates of the same type so that their absorption axes are parallel to each other. The orthogonal transmittance (H ₉₀ ) is a value of the transmittance of an orthogonal laminated polarizing plate produced by superposing two polarizing plates of the same type so that their absorption axes are orthogonal to each other. Note that these transmittances are Y values obtained by performing visibility correction with a two-degree field of view (C light source) defined in JlS Z 8701 (1982).

(4) Pencil hardness Pencil hardness was calculated | required by the test method according to JISK5400 (1990) using the pencil of different hardness.

(5) Adhesiveness Adhesiveness is applied to the surface of the hard coat layer after the surface opposite to the one on which the hard coat layer of the polarizing plate is formed is attached to the glass plate via an adhesive layer having a thickness of about 20 μm. A cross-cut peel test in accordance with JIS K 5400 was performed, and the determination was made according to the following index.
A: Number of peeled off 0/100
○: Number of peeled 1-5 / 100
(Triangle | delta): The number of peeling 6-20 / 100
X: Number of peeled pieces 21 to 99/100
XX: Number of peeled 100/100

[Example 1]
(Production of polarizer)
Dip a 75 μm thick polyvinyl alcohol film (Kuraray Co., Ltd., trade name “VF-PS # 7500”) in 5 baths under the following conditions (1) to (5) while applying tension in the longitudinal direction of the film. And it extended | stretched so that the final draw ratio might be 6 time with respect to the original length of a film. The stretched film was dried in an air circulation drying oven at 40 ° C. for 1 minute to produce a polarizer having a thickness of 30 μm.
<Conditions>
(1) Swelling bath: 30 ° C. pure water (2) Dyeing bath: 0.03 parts by weight of iodine with respect to 100 parts by weight of water, and 0.2 parts by weight of potassium iodide with respect to 100 parts by weight of water 30 ° C. aqueous solution (3) First crosslinking bath: 3% by weight potassium iodide and 3% by weight boric acid, 40 ° C. aqueous solution (4) Second crosslinking bath: 5% 60 ° C. aqueous solution containing 5% potassium iodide and 4% by weight boric acid (5) Washing bath: 25 ° C. aqueous solution containing 3% by weight potassium iodide

(Lamination of protective layer)
Next, a TAC film having a thickness of 80 μm (manufactured by Fuji Photo Film Co., Ltd.) is applied to one surface of the polarizer, and a water-soluble adhesive layer mainly composed of a polyvinyl alcohol resin having a thickness of 0.1 μm (Japan) Attached via a synthetic chemical industry (trade name “Gosefimer Z200”).

(Formation of intervening layer)
Next, on the other side of the polarizer, a coating liquid containing a thermosetting resin is applied to form a coating film, and then the coating film is cured by heating and drying to obtain a thickness. A 15 μm intervening layer was formed. The coating liquid comprises, as the thermosetting resin, 90 parts by weight of a water-based thermosetting silanol group-containing polycarbonate urethane resin (trade name “Takelac WS5100”, manufactured by Mitsui Chemicals, Inc.), an ultraviolet absorber (Ciba Specialty Chemicals). (Trade name "TINUVIN1130") 5 parts by weight and 5 parts by weight of a diluting solvent (ethanol) were prepared. The heat drying treatment was performed using an air circulation drying oven, and the drying temperature was 100 ° C. and the drying time was 2 minutes.

(Formation of hard coat layer)
Next, after applying a solvent-free photocurable composition on the intervening layer, using a high-pressure mercury lamp, the coated surface is irradiated with ultraviolet light having a wavelength of 365 nm so that the integrated light quantity becomes 300 mJ / cm ^2. Thus, a hard coat layer having a thickness of 10 μm was formed. The photocurable composition is a solvent-free type containing no solvent, and has the following composition.

Component (A): 54 parts by weight of the monomer represented by the structural formula (II) (product name “KAYARAD DPHA” (Mw = 578), manufactured by Nippon Kayaku Co., Ltd.) Component (B): Polyurethane acrylate ( Nippon Synthetic Chemical Industry Co., Ltd., trade name “purple light UV-1700B”) 18 parts by weight Component (C): Photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, Ciba Specialty Chemicals Co., Ltd., product) Name “IRGACURE184”) 5 parts by weight Component (D): Reactive diluent (acryloylmorpholine, manufactured by Kojin Co., Ltd.) 23 parts by weight

  Thus, the polarizing plate 101 having the configuration shown in FIG. 2 was produced. The single transmittance (T) of the polarizing plate 101 of this example was 43.7%, and the degree of polarization (P) was 99.9%.

(Example 2)
As the coating liquid used for forming the intervening layer, 69 parts by weight of a solvent-based thermosetting polyester urethane resin (manufactured by Toyobo Co., Ltd., trade name “Byron UR1350”) as the thermosetting resin, UV absorber (Ciba -Specialty Chemicals Co., Ltd., trade name "CGL777" 1 part by weight, polyisocyanate resin (Japan Polyurethane Industry Co., Ltd., trade name "Coronate HX") 7 parts by weight and diluent solvent (ethyl acetate) 23 parts by weight A polarizing plate 101 having the configuration shown in FIG. 2 was produced in the same manner as in Example 1, except that a mixture prepared by mixing parts was used. The single transmittance (T) of the polarizing plate 101 of this example was 43.6%, and the degree of polarization (P) was 99.9%.

(Example 3)
Example 1 was used except that a water-based thermosetting polyester urethane resin (manufactured by Enomoto Kasei Co., Ltd., trade name “Neorez R9660”) was used as the thermosetting resin used for forming the intervening layer. Thus, a polarizing plate 101 having the configuration shown in FIG. 2 was produced. The single transmittance (T) of the polarizing plate 101 of this example was 43.5%, and the degree of polarization (P) was 99.9%.

Example 4
As in Example 1, except that a water-based thermosetting polycarbonate urethane resin (trade name “Takelac W6010” manufactured by Mitsui Chemicals, Inc.) was used as the thermosetting resin used for forming the intervening layer. Thus, a polarizing plate 101 having the configuration shown in FIG. 2 was produced. The single transmittance (T) of the polarizing plate 101 of this example was 43.3%, and the degree of polarization (P) was 99.9%.

(Comparative Example 1)
Instead of forming the intervening layer, after applying a photocurable composition on the other side of the polarizer, using a high-pressure mercury lamp, ultraviolet light having a wavelength of 365 nm is applied to the coated surface with an integrated light quantity of 600 mJ / Irradiate to a cm ² to form a 20 μm thick photocured material layer, and form a hard coat layer thereon in the same manner as in Example 1. A plate was made. The photocurable composition is a solvent-based photocurable acrylic urethane resin and has the following composition.

72 parts by weight of urethane-based ultraviolet curable resin (Dainippon Ink Chemical Co., Ltd., trade name “GRANDIC PC-1070”) 1 part by weight of UV absorber (Ciba Specialty Chemicals, trade name “CGL777”) Photopolymerization initiator (bis (2,4,6-trimethylbenzoyl) -phenylphosphine oxide, manufactured by Ciba Specialty Chemicals, Inc., trade name “IRGACURE819”) 2 parts by weight ethyl acetate 25 parts by weight

(Comparative Example 2)
Instead of forming the intervening layer, after applying a photocurable composition on the other side of the polarizer, using a high-pressure mercury lamp, ultraviolet light having a wavelength of 365 nm is applied to the coated surface with an integrated light quantity of 600 mJ / Irradiation to a thickness of cm ² , a 10 μm thick photocured product layer was formed, and a hard coat layer was formed thereon in the same manner as in Example 1. A plate was made. The photocurable composition is a solvent-free photocurable polyurethane acrylate resin and has the following composition.

Monomer represented by the structural formula (II) (manufactured by Nippon Kayaku Co., Ltd., trade name “KAYARAD DPHA” (Mw = 578)) 49 parts by weight polyurethane acrylate (manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name “ Purple light UV-1700B ") 16 parts by weight photopolymerization initiator (1-hydroxycyclohexyl phenyl ketone, manufactured by Ciba Specialty Chemicals, Inc., trade name" IRGACURE184 "and bis (2,4,6-trimethylbenzoyl) -phenyl Phosphine oxide, manufactured by Ciba Specialty Chemicals Co., Ltd., trade name “IRGACURE819”) 5 parts by weight each reactive diluent (acryloylmorpholine, manufactured by Kojin Co., Ltd.) 21 parts by weight UV absorber (Ciba Specialty)・ Chemicals Co., Ltd., trade name “CGL777”) 4 parts by weight

  Table 1 below shows the results of evaluating pencil hardness and adhesion for each of the polarizing plates of Examples 1 to 4 and Comparative Examples 1 and 2 together with the forming material, the curing means, and the thickness of each layer. In Table 1 below, the HC layer represents a hard coat layer.

  As shown in Table 1, each of the polarizing plates of Examples 1 to 4 was thin, had a hardness of H and high hardness, and had good adhesion. On the other hand, each polarizing plate of Comparative Examples 1 and 2 had poor adhesion, and the hard coat layer was easily peeled from the polarizer.

  As described above, the polarizing plate of the present invention can be thinned and has high performance that is excellent in adhesion and hardness of the hard coat layer. Applications of the polarizing plate of the present invention and an image display device using the polarizing plate are, for example, OA equipment such as a desktop personal computer, a notebook personal computer, and a copy machine, a mobile phone, a clock, a digital camera, a personal digital assistant (PDA), and a portable game machine. Portable devices such as video cameras, televisions, microwave ovens and other household electrical devices, back monitors, car navigation system monitors, car audio and other in-vehicle devices, commercial store information monitors and other display devices, monitoring monitors Such as security equipment such as nursing care, medical care monitor, and other nursing care / medical equipment, and the use thereof is not limited and can be applied to a wide range of fields.

FIG. 1 is a structural cross-sectional view showing the structure of an example of the polarizing plate of the present invention. FIG. 2 is a structural sectional view showing the structure of another example of the polarizing plate of the present invention. FIG. 3 is a structural sectional view showing the structure of still another example of the polarizing plate of the present invention. FIG. 4 is a structural sectional view showing the structure of still another example of the polarizing plate of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 11 Polarizer 12 Intervening layer 13 Hard-coat layer 21 Adhesive layer 22 Protective layer 31 Fine particle 41 Antireflection layer 100,101,102,103 Polarizing plate

Claims (9)

On at least one surface of the polarizer, intervening layer formed of a thermosetting resin is laminated directly on the intermediate layer, a hard coat layer formed from the photocurable resin is laminated directly,
The polarizer includes a hydrophilic polymer;
The thermosetting resin that is the material for forming the intervening layer is a solvent-based thermosetting polyester urethane resin, a water-based thermosetting polyester urethane resin, a water-based thermosetting silanol group-containing polycarbonate urethane resin, and a water-based thermosetting carbonate urethane resin. Including at least one selected from the group consisting of:
The photocurable resin that is the material for forming the hard coat layer includes a solvent-free photocurable composition containing the following components (A), (B), and (C):
The thickness of each layer of the intervening layer and the hard coat layer is in the range of 5 to 25 μm.
Polarizer.
(A) At least one of a polyfunctional acrylic monomer and a polyfunctional methacrylic monomer represented by the following general formula (I)
(B) A photocurable prepolymer that is at least one of polyurethane acrylate and polyurethane methacrylate
(C) Photopolymerization initiator

In the general formula (I), R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ are each independently a hydrogen atom, an acryloyl group or a methacryloyl group, and R ₁ , R ₂ , In R ₃ , R ₄ , R ₅ and R ₆ , at least 4 are an acryloyl group or a methacryloyl group. The polarizing plate according to claim 1, wherein the intervening layer contains an ultraviolet absorber. Furthermore, the said solventless photocurable composition is a polarizing plate of Claim 1 or 2 containing the following (D) component.
(D) Reactive diluent The polarizing plate according to claim 1, wherein the hydrophilic polymer contains a polyvinyl alcohol-based resin. The polarizing plate according to claim 1, wherein the polarizer includes a dichroic substance and a polyvinyl alcohol-based resin. The polarizing plate as described in any one of Claim 1 to 5 in which the said polarizer contains an iodine and polyvinyl alcohol-type resin. An image display device equipped with a polarizing plate, wherein the polarizing plate is the polarizing plate according to any one of claims 1 to 6 . A method for producing a polarizing plate according to any one of claims 1 to 6,
The manufacturing method of the polarizing plate characterized by including the process of following (A) and (B).
(A) A coating liquid containing a thermosetting resin is directly applied to at least one surface of a polarizer to form a coating film, and the coating film is heated and cured to form an intervening layer. Process.
(B) On the intervening layer, a coating liquid containing the photo-curable resin is applied to form a coating film, and the coating film is cured by light irradiation treatment to form a hard coat layer. Forming step. Furthermore, the manufacturing method of the polarizing plate of Claim 8 including the following (C) process.
(C) The process of laminating | stacking a protective layer on the other surface of the said polarizer through an adhesive bond layer or an adhesive layer.

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