JP2006018089A - Polarizing plate and liquid crystal display device - Google Patents

Abstract

Disclosed is a polarizing plate and a liquid crystal display device that are excellent in transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion by making a transparent protective layer of a polarizer specific. is there.
At least a transparent protective layer (A), a hard coat layer (B), and a low refractive index layer (C) are laminated in this order on one surface of a polarizer, and transparent on the other surface of the polarizer. In the polarizing plate in which the protective layer (D) is laminated, the transparent protective layer (A) is a film containing a polyester resin having a haze value of 1.0 or less at a thickness of 50 μm. A polarizing plate characterized in that the surface hardness is H or more in pencil hardness.

Description

  The present invention relates to a polarizing plate, and more specifically, a polarizing plate comprising a laminate obtained by laminating a transparent protective layer on both sides of a polarizer, and having excellent transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion. Is to provide.

A liquid crystal display device (hereinafter referred to as “LCD”) is characterized by being thin, lightweight, and consuming little power. The field of use of LCDs is expanding from conventional calculators and watches to automobile applications that require durability and heat resistance, such as car navigation systems and automobile inner panels.
The LCD is composed of a liquid crystal cell that has a function of switching the passage and blocking of polarized light by controlling the orientation direction of the liquid crystal by applying an electric field, and a polarizing plate arranged at right angles with the liquid crystal cell in between. Is done.
As a polarizing plate, what laminated | stacked the polarizing plate protective film on both polarizers is used. The protective film is a film that is attached to the outside of the polarizer for scratch resistance, antireflection properties, and the like of the liquid crystal display element.
As a material of the polarizer, polyvinyl alcohol (hereinafter referred to as “PVA”) is mainly used. Specifically, the polarizer is uniaxially stretched from a PVA film, and then iodine or a dichroic dye. A polarizer is formed by dyeing or stretching after dyeing and further crosslinking with a boron compound. However, since this PVA polarizer has low mechanical strength and shrinks due to heat and moisture, the polarizing function is lowered. In order to prevent this, protective layers are laminated on both sides.
Protective layer has high light transmittance, excellent moisture and heat resistance, excellent mechanical properties, smooth surface, good adhesion to polarizer, etc. Is required.
A polarizing plate is known in which cellulose triacetate (TAC) is used as a protective layer and is bonded to a polarizer with a water-soluble adhesive. In order to prevent adhesion and scratches of dust and foreign substances on the polarizing plate, a hard coat layer is provided on the TAC protective layer or an antistatic layer is provided.
The present applicant has proposed to use a thermoplastic norbornene-based resin as a protective layer (for example, Patent Document 1). According to this, providing a polarizer protective layer excellent in water resistance, moisture resistance, physical strength, heat resistance, transparency, low birefringence, adhesion to an adhesive, durability to an adhesive, and the like. Can do.
On the other hand, a polarizing plate is also disposed on the front side of a liquid crystal cell in an LCD and may be exposed to the outside, so that it is easily damaged by physical damage. Further enhancement of scratch resistance and surface hardness is desired. In addition, it is also desired that the LCD display unit is made easy to see the screen by preventing reflection of external light, reflection, glare, etc., and that there is no dust adhesion due to static electricity. Therefore, it has been studied to provide a hard coat layer, an antireflection layer, an antistatic layer, etc. on the surface of the protective film, but it is still insufficient, and there is a need for a polarizing plate that can satisfy all of these characteristics. Yes.

JP-A-6-511117 JP 2003-149403 A JP 2003-185841 A

  The present invention has been made in view of the state of the prior art, and by making the transparent protective layer of the polarizer specific, transparency, mechanical strength, antireflection performance, scratch resistance, adhesion It is providing the polarizing plate and liquid crystal display device which are excellent in all of these.

  As a result of diligent research to solve the above problems, the present inventors sequentially laminated a polarizer, a transparent protective layer, a hard coat layer, and a low refractive index layer, and formed a transparent protective layer on the other surface of the polarizer. As a result, the polarizing plate of the present invention that is optimal for the liquid crystal display element was completed.

Thus, according to the present invention,
(1) At least a transparent protective layer (A), a hard coat layer (B), and a low refractive index layer (C) are laminated in this order on one surface of the polarizer, and transparent protection is provided on the other surface of the polarizer. In the polarizing plate in which the layer (D) is laminated, the transparent protective layer (A) is a film containing a polyester resin having a haze value of 1.0 or less at a thickness of 50 μm,
The polarizing plate is characterized in that the surface hardness of the polarizing plate is H or more in pencil hardness.
(2) The polarizing plate of (1) or (2), wherein the refractive index of the low refractive index layer (C) is 1.36 or less.
(3) The polarizing plate according to any one of (1) to (3), wherein the low refractive index layer (C) is a layer containing an airgel made of silicon oxide.
(4) The polarizing plate according to any one of (1) to (4), wherein the transparent protective layer (D) is a polymer resin having an alicyclic structure or a cellulose resin.
(5) The polarizing plate according to any one of (1) to (4), wherein the transparent protective layer (D) is a layer exhibiting a retardation.
(6) A liquid crystal display device in which the transparent protective layer (A) side of the polarizing plate of any one of (1) to (6) is disposed on the viewing side.
Are provided respectively.

  The polarizing plate of the present invention is a polarizing plate excellent in transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion, and the polarizing plate can be suitably used as a liquid crystal display device.

  In the polarizing plate of the present invention, at least a transparent protective layer (A) and an antireflection layer (B) having a low refractive index are laminated on one surface of a polarizer, and a transparent protective layer ( C) is laminated, and a transparent protective layer (D) is laminated on the other surface of the polarizer.

Polarizer for use in a polarizer present invention is not particularly limited as long as it has a function as a polarizer. For example, (1) vinyl alcohol polymer (PVA) / iodine polarizer, (2) PVA / dye polarizer with dichroic dye adsorbed and oriented on PVA film, (3) dehydrated from PVA film A polyene polarizer in which a polyene is formed by inducing a reaction or by dehydrochlorination of a polyvinyl chloride film, (4) the surface and / or the inside of a PVA film comprising a modified PVA containing a cationic group in the molecule And a polarizer having a dichroic dye. From the viewpoint of the initial polarization performance of the polarizer, (1) a PVA / iodine-based polarizer is preferable, and from the viewpoint of heat resistance, (2) a PVA / dye-based polarizing film is preferable.

A polarizer is not specifically limited by the manufacturing method. For example, 1) a method of adsorbing iodine ions after stretching a PVA-based film, 2) a method of stretching a PVA-based film after dyeing with a dichroic dye, and 3) after stretching a PVA-based film, using a dichroic dye There are known methods such as a dyeing method, 4) a method of drawing a dichroic dye on a PVA film and then stretching, and 5) a method of printing a dichroic dye after stretching the PVA film.
For example, in the method of 1), more specifically, iodine is dissolved in a potassium iodide solution to form iodine ions, the ions are adsorbed on a PVA film and stretched, and then bathed in a 1 to 4% boric acid aqueous solution. A polarizing plate is produced by dipping at a temperature of 30 to 40 ° C. More specifically, in the method of 2), the PVA film is dipped in a boric acid aqueous solution in the same manner as in 1), and then stretched about 3 to 7 times in the uniaxial direction, and 0.05 to 5% dichroic dye. It is immersed in an aqueous solution at a bath temperature of 30 to 40 ° C. to adsorb the dye, dried at 80 to 100 ° C. and thermally fixed to produce a polarizer. The polarization degree of the polarizer is preferably 99.993% or more.

Transparent protective layer (A)
The transparent protective layer (A) of the present invention contains a polyester resin. Examples of such polyester include polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and copolymers having these constituents as main components.

  As a polyester resin copolymer used for a polyester resin film, a crystalline polyester resin mainly composed of terephthalic acid is 98 to 80 wt%, a crystal segment having a melting point of 170 ° C. or more, and a melting point or softening point is 100 ° C. or less, and a molecular weight is Examples include a copolymer of 2 to 20 wt% of a block copolymer polyester resin composed of 400 to 8000, preferably 800 to 4000 soft polymer segments.

In the block copolymer polyester resin, the crystal segment having a melting point of 170 ° C. or higher has a melting point of 170 ° C. or higher when only the component is used as a polymer. For example, residues of aromatic dicarboxylic acids such as terephthalic acid, isophthalic acid, 2,6-naphthalenedicarboxylic acid, and aliphatics such as ethylene glycol, propylene glycol, butanediol, pentamethylene glycol, P-xylene glycol, and cyclohexanedimethanol Polyester composed of residues of aromatic and alicyclic diols can be used.
Further, the soft polymer segment having a molecular weight of 400 to 8000 is one having a melting point or a softening point of 100 ° C. or less when measured only with the segment constituent components. When such a block copolymer polyester resin is used, the adhesiveness with the adhesive is excellent.

  The transparent protective layer (A) used for the polarizing plate of the present invention is a film containing a polyester resin having a haze value of 1.0 or less at a thickness of 50 μm, but the transparent protective layer (A) of the present invention. The polyester used in the polyester resin film is not particularly limited as long as the above conditions are satisfied.

In this polyester, various additives such as antioxidants, heat stabilizers, weathering stabilizers, ultraviolet absorbers, infrared absorbers, organic lubricants, pigments, dyes, organic or inorganic fine particles, fillers, An antistatic agent, a nucleating agent, and the like may be appropriately selected and added depending on the application.
Since the type and amount of the additive adversely affect the haze and the like of the polyester film of the present invention, the haze at a thickness of 50 μm should be 1.0% or less, preferably 0.5% or less. Is preferred.

In this invention, the manufacturing method of the polyester resin film which comprises a transparent protective layer (A) can be obtained by shape | molding in a film form with a well-known shaping | molding method.
For example, a polymer resin having a polyester resin is melted by an extruder, extruded from a die attached to the extruder into a sheet shape, and the extruded sheet-shaped polyester resin film is brought into close contact with at least one cooling drum. Thus, it is obtained by having a step of taking up.

When the haze value at a thickness of 50 μm of the transparent protective layer (A) exceeds 1.0%, the total light transmittance is undesirably lowered. The haze value is 1.0% or less, preferably 0.5% or less. The haze value is measured using a commercially available turbidimeter in accordance with ASTM D1003.
In the present invention, the tensile strength in the take-up direction (MD direction) measured in accordance with JIS K7127 of the transparent protective layer (A) to be used is preferably 10 MPa or more, and more preferably 15 MPa or more. When the tensile strength in the length direction measured in accordance with JIS K7127 of the transparent protective layer (A) is in the above range, the surface strength of the film, distortion due to heat and humidity is alleviated. Further, the pencil hardness value measured according to JIS K5400 (overweight 500 g), the value of the pencil hardness of the film is B or more, preferably HB or more. When the pencil hardness is in the above range, the scratch resistance is improved.

  In the present invention, the transparent protective layer (A) has a total light transmittance at a thickness of 100 μm of 80% or more, preferably 90% or more.

The thickness of the transparent protective layer (A) is usually 10 to 500 μm from the viewpoint of easy handling and workability, and preferably 30 to 300 μm, more preferably 40 to 200 μm from the viewpoint of transparency and mechanical strength. It is.
The transparent protective layer (A) may be a single layer or multiple layers, but is usually a single layer.
Moreover, as a transparent protective layer (A), what gave the surface modification process to the single side | surface or both surfaces can be used. By performing the surface modification treatment, adhesion to the low refractive index layer and other layers described later can be improved. Examples of the surface modification treatment include energy beam irradiation treatment and chemical treatment.

  Examples of the energy ray irradiation treatment include corona discharge treatment, plasma treatment, electron beam irradiation treatment, ultraviolet ray irradiation treatment and the like. From the viewpoint of treatment efficiency, corona discharge treatment and plasma treatment are preferred, and corona discharge treatment is particularly preferred. As the chemical treatment, it may be immersed in an aqueous oxidizing agent solution such as potassium dichromate solution or concentrated sulfuric acid and then thoroughly washed with water. It is effective to shake in the immersed state, but there is a problem that the surface dissolves or transparency decreases when treated for a long period of time. Depending on the reactivity, concentration, etc. of the chemical used, the treatment time etc. Need to adjust.

Hard coat layer (B)
In this invention, it is preferable to have a hard-coat layer (B) on a transparent protective layer (A). The hard coat layer (B) preferably has a high-refractive index layer, a reflection plate that prevents reflection of external light, etc., and has excellent scratch resistance and antifouling properties. It becomes possible.
Further, in the polarizing plate of the present invention, the hard coat layer (B) can serve as a protective film and a high refractive index layer, so that not only thinning but also manufacturing cost can be reduced.
In the present invention, the hard coat layer (B) also serving as a high refractive index layer refers to a layer having a refractive index layer larger than that of the low refractive index layer (C). Although the refractive index of a high refractive index layer should just satisfy the said conditions, it is preferable that it is 1.55 or more.
The refractive index can be obtained by measuring using, for example, a known spectroscopic ellipsometer.

  The material for forming the hard coat layer is not particularly limited as long as it shows a hardness of “HB” or higher in the pencil hardness test specified in JIS K5400. Examples thereof include organic hard coat materials such as organic silicone, melamine, epoxy, acrylic, and urethane acrylate; inorganic hard coat materials such as silicon dioxide; and the like. Of these, urethane acrylate-based and polyfunctional acrylate-based hard coat materials are preferably used from the viewpoint of good adhesive strength and excellent productivity.

  The method for forming the hard coat layer (B) is not particularly limited. For example, the coating liquid for forming a high refractive index layer is coated on a support by a known coating method, and is formed by irradiating with ultraviolet rays and curing. The method of doing is mentioned. Although the thickness of a high refractive index layer is not specifically limited, Usually, 0.5-30 micrometers, Preferably it is 3-15 micrometers.

  The hard coat layer includes an active energy ray-curable resin, and has a refractive index of 1.55 or more as a whole. By containing an active energy ray-curable resin, a high refractive index layer having sufficient strength, durability, adhesion, and transparency can be obtained.

  The active energy ray-curable resin is a resin obtained by curing a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in a molecule by irradiation with active energy rays. An active energy ray refers to an electromagnetic wave or a charged particle beam having an energy quantum capable of polymerizing or crosslinking molecules, and usually an ultraviolet ray or an electron beam is used.

  Examples of prepolymers and oligomers having a polymerizable unsaturated bond or epoxy group in the molecule include unsaturated polyesters such as a condensation product of unsaturated dicarboxylic acid and polyhydric alcohol; polyester methacrylate, polyether methacrylate, polyol methacrylate And methacrylates such as melamine methacrylate, polyester acrylates, epoxy acrylates, urethane acrylates, polyether acrylates, polyol acrylates, acrylates such as melamine acrylates, and cationic polymerization type epoxy compounds.

Examples of the monomer having a polymerizable unsaturated bond or epoxy group in the molecule include styrene monomers such as styrene and α-methylstyrene; methyl acrylate, ethyl acrylate, -2-ethylhexyl acrylate, methoxy acrylate Acrylic esters such as ethyl, butoxyethyl acrylate, butyl acrylate, methoxybutyl acrylate, and phenyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, methoxyethyl methacrylate, ethoxymethyl methacrylate, methacrylic acid Methacrylic acid esters such as phenyl and lauryl methacrylate; acrylic acid-2- (N, N-diethylamino) ethyl, acrylic acid-2- (N, N-dimethylamino) ethyl, acrylic acid-2- (N, N -Dibenzylamino) methyl, acrylic -2-(N, N-diethylamino) substituted amino alcohol esters of unsaturated substituted and propyl; acrylamide, unsaturated carboxylic acid amides such as methacrylamide;

Ethylene glycol diacrylate, propylene glycol diacrylate, neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, triethylene glycol diacrylate, dipropylene glycol diacrylate, ethylene glycol diacrylate, propylene glycol dimethacrylate, diethylene glycol dimethacrylate 2-hydroxy acrylate, 2-hexyl acrylate, phenoxyethyl acrylate, ethylene glycol diacrylate, 1,6-hexanediol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, dipentaerythritol hexaacrylate Multifunctional Acrela such as REIT G
And polythiols having two or more thiol groups in the molecule, such as trimethylolpropane trithioglycolate, trimethylolpropane trithiopropylate, and pentaerythritol tetrathioglycolate.
In the present invention, these prepolymers, oligomers and / or monomers can be used singly or in combination of two or more.

For the hard coat layer, an energy ray curable resin is used for the purpose of adjusting the refractive index, improving the flexural modulus, stabilizing the volume shrinkage, heat resistance, antistatic property, antiglare property, etc., if desired. In addition, for example, various fillers such as silica, alumina, hydrated alumina and the like may be added, and it is preferable to further include inorganic oxide particles.
Furthermore, various additives such as an antioxidant, an ultraviolet absorber, a light stabilizer, an antistatic agent, a leveling agent, and an antifoaming agent can be added.
By adding inorganic oxide particles, a high refractive index layer having excellent scratch resistance and a refractive index of 1.55 or more can be easily formed.

  As the inorganic oxide particles that can be used in the hard coat layer (B), those having a high refractive index are preferable. Specifically, the refractive index of the inorganic oxide particles is preferably 1.7 or more, and more preferably 1.7 to 2.3.

Examples of the inorganic oxide having a high refractive index include titania (titanium oxide), zirconia (zirconium oxide), zinc oxide, tin oxide, cerium oxide, antimony oxide, tin-doped indium oxide (ITO), and antimony. Examples thereof include tin oxide (ATO), zinc-doped indium oxide (IZO), aluminum-doped zinc oxide (AZO), and fluorine-doped tin oxide (FTO).
In addition, metal oxide such as alumina, silica, zinc oxide, zirconium oxide, tin oxide doped with antimony (ATO), indium oxide doped with tin (ITO), indium oxide doped with zinc (IZO), aluminum Doped zinc oxide (AZO), fluorine-doped tin oxide (FTO), antimony pentoxide, tin oxide, tin-doped indium oxide (ITO),
And tin oxide (ATO) doped with antimony, indium oxide (IZO) doped with zinc, zinc oxide (AZO) doped with aluminum, tin oxide (FTO) doped with fluorine, and the like.
Among these, antimony oxide is suitable as a component for adjusting the refractive index because of its high refractive index and excellent balance between conductivity and transparency.
These inorganic oxide particles can be used singly or in combination of two or more.

  The inorganic oxide particles have a so-called ultrafine particle size, more specifically, a primary particle size of 1 nm or more and 100 nm or less, preferably 30 nm or less so as not to lower the transparency of the hard coat layer. It is preferable to use it.

  The primary particle diameter of the inorganic oxide particles may be visually measured from a secondary electron emission image photograph obtained by a scanning electron microscope (SEM) or the like, or a dynamic light scattering method or a static light scattering method may be used. Mechanical measurement may be performed by a particle size distribution meter to be used.

  If the primary particle diameter of the inorganic oxide particles is within the above range, the particle shape can be used in the present invention regardless of whether it is spherical, needle-shaped, or any other shape. In the case of an acicular shape, the length is 100 nm or less, preferably 50 nm or less.

  Further, as the inorganic oxide particles that can be used in the present invention, at least a part of the surface thereof is coated with an organic compound or an organometallic compound having an anionic polar group in order to enhance dispersibility in an organic solvent. It is preferable that When the hard coat layer is formed by a wet method, the dispersibility of the inorganic oxide particles in the dispersion used can be improved.

  As the organic compound having an anionic polar group, those having an anionic polar group such as a carboxyl group, a phosphate group, or a hydroxyl group can be used. Examples thereof include stearic acid, lauric acid, oleic acid, linoleic acid, linolenic acid, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, EO (ethylene oxide) -modified phosphoric acid triacrylate, ECH-modified glycerol triacrylate, and the like.

  Examples of the organometallic compound having an anionic polar group include 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N- (2-aminoethyl) 3-aminopropylmethyldiethoxysilane, 3-mercaptopropyltrimethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane Silane coupling agents such as vinyltris (2-methoxyethoxy) silane and 3-methacryloxypropyltrimethoxysilane; KR-TTS, KR-46B, KR-55, KR-41B, KR-38S, KR-138S, KR -238S, 338X, KR-44, KR-9S , KR-ET (above, titanate coupling agent manufactured by Ajinomoto Fine Techno Co., Ltd.), tetramethoxy titanium, tetraethoxy titanium, tetraisopropoxy titanium, tetra n-propoxy titanium, tetra n-butoxy titanium, tetra sec-butoxy And titanate coupling agents such as titanium and tetra-tert-butoxytitanium;

  The inorganic oxide particles having a surface coated with an organic compound and / or an organic metal compound to impart hydrophobicity are obtained by dissolving the organic compound and / or the organic metal compound having the anionic polar group in an organic solvent. The organic solvent can be obtained by completely evaporating and removing the organic oxide after dispersing the inorganic oxide in the solution.

  Two or more inorganic oxide particles may be used in combination. In this case, a transparent thin film having a plurality of functions in a balanced manner can be formed by combining inorganic oxide particles having different main functions. For example, a predetermined refractive index is obtained by combining rutile-type titanium oxide fine particles having a very high refractive index but low conductivity and the above-described conductive inorganic oxide having extremely high conductivity but a refractive index smaller than that of rutile-type titanium oxide. It is possible to form a hard coat layer having good antistatic performance.

  The hard coat layer containing an active energy ray-curable resin is an active energy ray containing a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule, and optionally inorganic oxide particles. It can be formed by applying the curable resin composition on the support or other layers formed on the support surface, drying the resulting coating, and curing it by irradiating with active energy rays. it can.

  The content of the prepolymer, oligomer and / or monomer in the active energy ray-curable resin composition to be used is preferably 5% by weight to 95% by weight from the viewpoint of obtaining excellent coating suitability. Further, the amount of the inorganic oxide fine particles is not particularly limited, but from the viewpoint of easily obtaining a hard coat layer having excellent scratch resistance and a refractive index of 1.55 or more, the entire hard coat layer is used. Thus, it is preferably 40 to 90% by weight.

  When the active energy ray-curable resin composition is cured by ultraviolet irradiation, a photopolymerization initiator or a photopolymerization accelerator is added to the composition. As photopolymerization initiators, radical polymerization initiators such as acetophenones, benzophenones, thioxanthones, benzoin, benzoin methyl ether; aromatic diazonium salts, aromatic sulfonium salts, aromatic iodonium salts, metathelone compounds, benzoin sulfonic acids Cationic polymerizable initiators such as esters; These can be used individually by 1 type or in combination of 2 or more types. The addition amount of the photopolymerization initiator is usually 0.1 to 10 parts by weight with respect to 100 parts by weight of the active energy ray-curable resin composition.

In addition, an organic reactive silicon compound may be added to the active energy ray-curable resin composition. Examples of the organic reactive silicon compound used include tetramethoxysilane, tetraethoxysilane, tetraisopropoxysilane, tetra-n-propoxysilane, tetra-n-butoxysilane, tetra-sec-butoxysilane, tetra-tert-butoxysilane, Methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltributoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, dimethylethoxysilane, dimethylmethoxysilane, dimethylpropoxysilane, dimethylbutoxysilane, methyldimethoxysilane, methyl diethoxy silane, hexyl trimethoxy silane, _{formula: R m Si (oR ')} n ( wherein, R and R' each independently represent an alkyl group having 1 to 10 carbon atoms, m, n it Is independently an organic silicon compound expressed by satisfying the relationship of m + n = 4 is a positive integer).;

  γ- (2-aminoethyl) aminopropyltrimethoxysilane, γ- (2-aminoethyl) aminopropylmethyldimethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, γ-aminopropyltriethoxysilane , Γ-methacryloxypropylmethoxysilane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropylmethoxysilane hydrochloride, γ-glycidoxypropyltrimethoxysilane, aminosilane, methylmethoxysilane, vinyltri Acetoxysilane, γ-mercaptopropyltrimethoxysilane, γ-chloropropyltrimethoxysilane, hexamethyldisilazane, vinyltris (β-methoxyethoxy) silane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium chloride, methyltri Silane coupling agents such as chlorosilane and dimethyldichlorosilane;

  One-end vinyl group-substituted polysilane, both-end vinyl group-substituted polysilane, one-end vinyl group-substituted polysiloxane, both-end vinyl group-substituted polysiloxane, vinyl group-substituted polysilane obtained by reacting these compounds, or vinyl group-substituted poly Active energy ray-curable silicon compounds such as siloxane; other organosilicon compounds such as 3- (meth) acryloxypropyltrimethoxysilane and (meth) acryloxysilane compounds such as 3- (meth) acryloxypropylmethyldimethoxysilane And the like.

  The active energy ray-curable resin composition that can be used comprises a prepolymer, an oligomer and / or a monomer having a polymerizable unsaturated bond or an epoxy group in the molecule, and, if desired, inorganic oxide particles in an appropriate organic form. It can be prepared by dissolving or dispersing in a solvent.

  Examples of the organic solvent that can be used include alcohols such as methanol, ethanol, isopropanol, n-butanol, and isobutanol; ethylene glycol, ethylene glycol monobutyl ether, ethylene glycol monoethyl ether, diethylene glycol, diethylene glycol monobutyl ether, diethylene glycol, Glycols such as acetone glycol; Aromatic hydrocarbons such as toluene and xylene; Aliphatic hydrocarbons such as n-hexane and n-heptane; Esters such as ethyl acetate and butyl acetate; Ketones such as methyl ethyl ketone and methyl isobutyl ketone Oximes such as methyl ethyl ketoxime; and combinations of two or more thereof; and the like.

  The method for coating the active energy ray-curable resin composition on the support is not particularly limited, and a known method can be employed. Examples of the coating method include a wire bar coating method, a dip method, a spray method, a spin coating method, and a roll coating method.

After obtaining the coating film of the active energy ray-curable resin composition, it can be dried and cured by irradiation with active energy rays to form a high refractive index layer.
The irradiation intensity and irradiation time of the active energy ray are not particularly limited, and irradiation conditions such as irradiation intensity and irradiation time can be appropriately set according to the composition of the active energy ray curable resin composition to be used.

The thickness of the hard coat layer is usually 1 to 20 μm, preferably 3 to 10 μm.
The entire hard coat layer has a refractive index of 1.50 or more, more preferably a refractive index of 1.55 or more.

Low refractive index layer (C)
The low refractive index layer (C) used in the present invention refers to a layer having a refractive index lower than that of the hard coat layer (B). The refractive index of the low refractive index layer (C) may satisfy the above conditions, but is preferably 1.36 or less, more preferably 1.35 to 1.25, and 1.34 to 1. 30 is particularly preferred. When the refractive index of the low refractive index layer is less than 1.25, the strength of the low refractive index layer is weak, and the desired scratch resistance required as a polarizing plate protective film may not be obtained. On the other hand, if it exceeds 1.36, the desired antireflection effect may not be obtained. The refractive index can be obtained by measuring using, for example, a known spectroscopic ellipsometer.

  The low refractive index layer used in the optical laminated film of the present invention is not particularly limited as long as it is a material constituting a layer having a refractive index of 1.36 or less, but it is easy to control the refractive index and water resistance. In terms of superiority, airgel is preferred.

The airgel is a transparent porous body in which minute bubbles are dispersed in a matrix. Most of the size of the bubbles is 200 nm or less, and the content of the bubbles is usually 10% by volume or more and 60% by volume or less, preferably 20% by volume or more and 40% by volume or less.
Specific examples of the airgel in which minute bubbles are dispersed include silica aerogel and a porous body in which hollow particles are dispersed in a matrix.

  Silica airgel is a wet state composed of a silica skeleton obtained by hydrolysis polymerization reaction of alkoxysilane as disclosed in US Pat. No. 4,402,927, US Pat. No. 4,432,956, US Pat. No. 4,610,863 and the like. The gel-like compound can be produced by drying in a supercritical state above the critical point of the solvent in the presence of a solvent (dispersion medium) such as alcohol or carbon dioxide. In supercritical drying, for example, a gel compound is immersed in liquefied carbon dioxide, and all or part of the solvent contained in the gel compound is replaced with liquefied carbon dioxide having a critical point lower than that of the solvent. It can be carried out by drying under supercritical conditions of a single system of or a mixed system of carbon dioxide and a solvent. Silica airgel may be produced in the same manner as described above using sodium silicate as a raw material as disclosed in US Pat. No. 5,137,279, US Pat. No. 5,124,364, and the like.

  Here, as disclosed in JP-A-5-279011 and JP-A-7-138375, the gel-like compound obtained by hydrolysis and polymerization reaction of alkoxysilane as described above is hydrophobized. It is preferable to impart hydrophobicity to the silica airgel. Hydrophobic silica airgel imparted with hydrophobicity as described above can prevent moisture, water, and the like from entering, and prevent the performance of the silica airgel from being degraded in refractive index, light transmittance, and the like.

  This hydrophobization treatment step can be performed before or during supercritical drying of the gel compound. The hydrophobization treatment is performed to make the hydrophobization by reacting the hydroxyl group of the silanol group present on the surface of the gel compound with the functional group of the hydrophobization treatment agent and replacing it with the hydrophobic group of the hydrophobization treatment agent. . As a method of performing the hydrophobization treatment, the gel is immersed in a hydrophobization treatment solution in which the hydrophobization treatment agent is dissolved in a solvent, mixed, and so on. There is a method in which the hydrophobization reaction is performed by heating accordingly.

  Examples of the solvent used for the hydrophobic treatment include methanol, ethanol, isopropanol, xylene, toluene, benzene, N, N-dimethylformamide, hexamethyldisiloxane, and the like, but the hydrophobic treatment agent can be easily dissolved. And what is necessary is just to be able to substitute for the solvent which the gel before hydrophobization treatment contains, and it is not limited to these. Further, when supercritical drying is performed in a later step, a medium that can be easily supercritically dried, such as methanol, ethanol, isopropanol, liquefied carbon dioxide, or the like, is preferable. Examples of the hydrophobizing agent include hexamethyldisilazane, hexamethyldisiloxane, trimethylmethoxysilane, dimethyldimethoxysilane, methyltrimethoxysilane, ethyltrimethoxysilane, trimethylethoxysilane, dimethyldiethoxysilane, and methyltriethoxysilane. Etc.

The refractive index of silica airgel can be freely changed by the raw material compounding ratio of silica airgel.
When the low refractive index layer is silica aerogel, the formation method of the low refractive index layer is not particularly limited. For example, the gel compound is applied on the high refractive index layer by a known coating method. And a method of forming by performing the above-mentioned supercritical drying. Further, the hydrophobization treatment may be performed before or during supercritical drying. In the supercritical drying, for example, the gel compound is immersed in liquefied carbon dioxide, and all or a part of the solvent containing the gel compound is replaced with liquefied carbon dioxide having a lower critical point than the solvent. It can be carried out by drying under supercritical conditions of a single system of carbon dioxide or a mixed system of carbon dioxide and a solvent.

As a porous material in which hollow particles are dispersed in a matrix, hollow fine particles having voids inside fine particles as disclosed in JP-A Nos. 2001-233611 and 2003-149642 are used as binder resins. And a porous material dispersed in the substrate.
The binder resin can be selected from resins suitable for conditions such as dispersibility of hollow fine particles, transparency of the porous body, and strength of the porous body. For example, conventionally used polyester resins and acrylic resins Resin, urethane resin, vinyl chloride resin, epoxy resin, melamine resin, fluorine resin, silicon resin, butyral resin, phenol resin, vinyl acetate resin, UV curable resin, electron beam curable resin, emulsion resin, water-soluble resin, hydrophilic resin Further, a mixture of these resins, a coating resin such as a copolymer or a modified product of these resins, a hydrolyzable organosilicon compound such as alkoxysilane, and a hydrolyzate thereof can be used.
Among these, hydrolyzable organosilicon compounds such as acrylic resins, epoxy resins, urethane resins, silicon resins, alkoxysilanes, and hydrolysates thereof are preferable from the viewpoint of the dispersibility of the fine particles and the strength of the porous body.
In the present invention, when a porous body in which hollow particles are dispersed in a matrix is used as the low refractive index layer, the reflection characteristics and antifouling properties of the low refractive index layer are improved. You may mix.
The fluororesin is not limited as long as it is an amorphous fluoropolymer that is substantially free of light scattering by crystals, but tetrafluoroethylene / vinylidene fluoride / hexafluoropropylene = 37-48 wt% / 15- An amorphous fluoroolefin copolymer such as a 35% by weight / 26 to 44% by weight terpolymer and a polymer having a fluorine-containing aliphatic ring structure are preferred because of excellent mechanical properties.

The hydrolyzable organosilicon compound such as alkoxysilane and the hydrolyzate thereof are formed from one or more compounds selected from the group consisting of the following (a) to (c), and in the molecule: -(O-Si) _m -O- (wherein _m represents a natural number) has a bond.
(A) A compound represented by formula (1): SiX ₄ .
(B) At least one partial hydrolysis product of the compound represented by the formula (1).
(C) At least one complete hydrolysis product of the compound represented by the formula (1).

In the compound represented by the formula (1) in (a), X is a halogen atom such as a chlorine atom or a bromine atom; a monovalent hydrocarbon group which may have a substituent; an oxygen atom; Organic acid radicals such as nitrate radicals; β-diketonate groups such as acetylacetonate; inorganic acid radicals such as nitrate radicals and sulfate radicals; alkoxy groups such as methoxy groups, ethoxy groups, n-propoxy groups, and n-butoxy groups; or hydroxyl groups Represents.
Among these, as the compound represented by the formula (1), the formula (2): R _a SiY _4-a [wherein, R represents a hydrocarbon group which may have a substituent, a Represents an integer of 0 to 2, and when a is 2, R may be the same or different. Y represents a hydrolyzable group, and Y may be the same or different. ] The silicon compound represented by this is preferable.

  Examples of the monovalent hydrocarbon group which may have a substituent include alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group, a hexyl group, a heptyl group, and an octyl group; a cyclopentyl group, A cycloalkyl group such as a cyclohexyl group; an aryl group optionally having a substituent such as a phenyl group, a 4-methylphenyl group, a 1-naphthyl group, and a 2-naphthyl group; an alkenyl group such as a vinyl group and an allyl group; Aralkyl groups such as benzyl group, phenethyl group and 3-phenylpropyl group; haloalkyl groups such as chloromethyl group and γ-chloropropyl group; 3,3,3-trifluoropropyl group, methyl-3,3,3-tri Perfluoroalkyl group such as fluoropropyl group, heptadecafluorodecyl group, trifluoropropyl group, tridecafluorooctyl group; Alkenylcarbonyloxyalkyl groups such as methacryloxypropyl groups; alkyl groups having epoxy groups such as γ-glycidoxypropyl groups and 3,4-epoxycyclohexylethyl groups; alkyl groups having mercapto groups such as γ-mercaptopropyl groups An alkyl group having an amino group such as a 3-aminopropyl group; Among these, an alkyl group having 1 to 4 carbon atoms, a perfluoroalkyl group, and a phenyl group are preferable because of easy synthesis, easy availability, and low reflection characteristics.

In the formula (2), Y represents a hydrolyzable group. Here, the hydrolyzable group refers to a group that is hydrolyzed in the presence of an acid or a base catalyst as desired to form a — (O—Si) _m —O— bond.
Specific examples of the hydrolyzable group include alkoxy groups such as methoxy group, ethoxy group and propoxy group; acyloxy groups such as acetoxy group and propionyloxy group; oxime group (—O—N═C—R ′ (R ″) )), Enoxy group (—O—C (R ′) ═C (R ″) R ′ ″), amino group, aminoxy group (—O—N (R ′) R ″), amide group (— N (R ′) — C (═O) —R ″) and the like. In these groups, R ′, R ″, and R ′ ″ each independently represent a hydrogen atom or a monovalent hydrocarbon group. Among these, Y is preferably an alkoxy group from the viewpoint of availability.

  The silicon compound represented by the formula (2) is preferably a silicon compound in which a is an integer of 0 to 2 in the formula (2). Specific examples thereof include alkoxysilanes, acetoxysilanes, oxime silanes, enoxysilanes, aminosilanes, aminoxysilanes, amidosilanes and the like. Among these, alkoxysilanes are more preferable because of their availability.

  In the formula (2), examples of the tetraalkoxysilane in which a is 0 include tetramethoxysilane and tetraethoxysilane. Examples of the organotrialkoxysilane in which a is 1 include methyltrimethoxysilane and methyltriethoxy. Examples include silane, methyltriisopropoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, 3,3,3-trifluoropropyltrimethoxysilane, and the like. Examples of the diorganodialkoxysilane in which a is 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, and methylphenyldimethoxysilane.

  The molecular weight of the compound represented by the formula (1) is not particularly limited, but is preferably 40 to 300, and more preferably 100 to 200.

  At least one partial hydrolysis product (hereinafter referred to as “compound (3)”) of the compound represented by formula (1) of (b), and represented by formula (1) of (c). At least one complete hydrolysis product of the compound (hereinafter referred to as “compound (4)”) is obtained by fully or partially hydrolyzing one or more of the compounds represented by the formula (1). Can be obtained by condensation.

Compound (3) and compound (4) are, for example, a metal tetraalkoxide represented by Si (Or) ₄ (r represents a monovalent hydrocarbon group) and a molar ratio [H ₂ O] / [Or ] Is 1.0 or more, for example, 1.0 to 5.0, preferably 1.0 to 3.0, and can be obtained by hydrolysis in the presence of water. Hydrolysis can be performed by stirring the whole volume at a temperature of 5 to 100 ° C. for 2 to 100 hours.

When hydrolyzing the compound represented by the formula (1), a catalyst may be used as necessary. The catalyst to be used is not particularly limited, but the obtained partial hydrolyzate and / or hydrolyzate is likely to have a two-dimensional cross-linked structure, and the condensed compound is easily made porous. From the viewpoint of shortening the time required, an acid catalyst is preferred.
The acid catalyst to be used is not particularly limited. For example, acetic acid, chloroacetic acid, citric acid, benzoic acid, dimethylmalonic acid, formic acid, propionic acid, glutaric acid, glycolic acid, maleic acid, malonic acid, toluenesulfonic acid, Organic acids such as acids; inorganic acids such as hydrochloric acid, nitric acid, and halogenated silane; acidic sol-like fillers such as acidic colloidal silica and oxidized titania sol; These acid catalysts can be used alone or in combination of two or more.
Instead of the acid catalyst, a base catalyst such as an aqueous solution of an alkali metal or alkaline earth metal hydroxide such as sodium hydroxide or calcium hydroxide, an aqueous ammonia or an aqueous solution of amines may be used.

  The molecular weights of the compound (3) and the compound (4) are not particularly limited, but usually the weight average molecular weight is in the range of 200 to 5,000.

The hollow fine particles are not particularly limited as long as they are inorganic compound fine particles, but the use of silica-based hollow fine particles is particularly preferable.
As the inorganic compound, an inorganic oxide is common. As the inorganic _{oxide, SiO 2, Al 2 O 3} , B 2 O 3, TiO 2, ZrO 2, SnO 2, Ce 2 O 3, P 2 O 5, Sb 2 O 3, MoO 3, ZnO 2, WO One or two or more of ₃ or the like can be mentioned. Examples of the two or more inorganic oxides include TiO ₂ —Al ₂ O ₃ , TiO ₂ —ZrO ₂ , In ₂ O ₃ —SnO ₂ , and Sb ₂ O ₃ —SnO ₂ . These can be used alone or in combination of two or more.

  As the inorganic hollow fine particles, (1) an inorganic oxide single layer, (2) a single layer of a composite oxide composed of different kinds of inorganic oxides, and (3) a double layer of the above (1) and (2) What is included can be used.

  The outer shell may be porous with pores, or the pores may be closed and the cavity sealed with respect to the outside of the outer shell. The outer shell is preferably a plurality of inorganic oxide coating layers comprising an inner first inorganic oxide coating layer and an outer second inorganic oxide coating layer. By providing the second inorganic oxide coating layer on the outer side, the fine pores of the outer shell are closed to make the outer shell dense, and furthermore, the inorganic hollow fine particles in which the inner cavity is sealed can be obtained. In particular, when a fluorine-containing organosilicon compound is used for forming the second inorganic oxide coating layer, the coating layer containing fluorine atoms is formed, so that the resulting particles have a lower refractive index and are reduced to an organic solvent. The dispersibility is good, and further, it is effective for imparting antifouling property to the low refractive index layer, which is preferable. Such fluorine-containing organic silicon compounds include 3,3,3-trifluoropropyltrimethoxysilane, methyl-3,3,3-trifluoropropyldimethoxysilane, heptadecafluorodecylmethyldimethoxysilane, heptadecafluorodecyl. Examples thereof include trichlorosilane, heptadecafluorodecyltrimethoxysilane, trifluoropropyltrimethoxysilane, and tridecafluorooctyltrimethoxysilane.

  The thickness of the outer shell is preferably in the range of 1 to 50 nm, particularly 5 to 20 nm. If the thickness of the outer shell is less than 1 nm, the inorganic hollow fine particles may not maintain a predetermined particle shape. On the other hand, when the thickness of the outer shell exceeds 50 nm, the cavities in the inorganic hollow fine particles are small, and as a result, the ratio of the cavities may be reduced and the refractive index may not be sufficiently lowered. Furthermore, the thickness of the outer shell is preferably in the range of 1/50 to 1/5 of the average particle diameter of the inorganic hollow fine particles.

When the first inorganic oxide coating layer and the second inorganic oxide coating layer are provided as outer shells as described above, the total thickness of these layers may be in the range of 1 to 50 nm. For the densified outer shell, the thickness of the second inorganic oxide coating layer is preferably in the range of 20 to 40 nm.
In addition, the solvent used when preparing the inorganic hollow fine particles and / or the gas that enters during drying may exist in the cavity, and a precursor substance for forming the cavity described later remains in the cavity. Also good.
The precursor material is a porous material that remains after removing some of the constituent components of the core particles from the core particles surrounded by the outer shell. As the core particles, porous composite oxide particles made of different types of inorganic oxides are used. The precursor material may remain slightly attached to the outer shell or may occupy the majority of the cavity.
The solvent or gas may be present in the pores of the porous material. If the removal amount of the constituent components of the core particles at this time increases, the volume of the cavity increases, and inorganic hollow fine particles having a low refractive index are obtained. Excellent prevention performance.

  The average particle size of the inorganic hollow fine particles is not particularly limited, but is preferably 5 to 2000 nm, and more preferably 20 to 100 nm. If it is smaller than 5 nm, the effect of lowering the refractive index due to hollowness is small. Conversely, if it is larger than 2000 nm, the transparency is extremely deteriorated, and the contribution due to diffuse reflection increases. Here, the average particle diameter is a number average particle diameter by observation with a transmission electron microscope.

  The method for producing inorganic hollow fine particles as described above is described in detail, for example, in JP-A-2001-233611, and the inorganic hollow fine particles that can be used in the present invention are produced based on the method described therein. In addition, commercially available inorganic hollow fine particles can also be used.

  The blending amount of the inorganic hollow fine particles is not particularly limited, but is preferably 10 to 30% by weight with respect to the entire low refractive index layer. When the blending amount of the inorganic fine particles is within this range, an optical laminated film having both low refractive index properties and scratch resistance can be obtained.

  The inorganic hollow fine particles can also be used in the form of a dispersion. The type of the organic solvent used in the dispersion is not particularly limited. For example, lower aliphatic alcohols such as methanol, ethanol, isopropanol (IPA), n-butanol, isobutanol; ethylene glycol, ethylene glycol mono Ethylene glycol derivatives such as butyl ether and ethylene glycol monoethyl ether; diethylene glycol derivatives such as diethylene glycol and diethylene glycol monobutyl ether; diacetone alcohol; aromatic hydrocarbons such as toluene and xylene; aliphatic carbonization such as n-hexane and n-heptane Hydrogen; esters such as ethyl acetate and butyl acetate; ketones such as acetone, methyl ethyl ketone and methyl isobutyl ketone; These organic solvents can be used alone or in combination of two or more.

  The formation method is not particularly limited when the inorganic hollow particles constituting the low refractive index layer are porous bodies dispersed in a matrix. For example, a hollow having voids at least inside the fine particles on the hard coat layer An example is a method in which a coating liquid containing fine particles containing a binder resin is applied by a known coating method and, if necessary, dried and heat-treated. The temperature of the heating performed as necessary is usually 50 to 200 ° C, preferably 80 to 150 ° C.

In the present invention, the refractive index of the low refractive index layer is 1.35 or less, preferably 1.34 to 1.25, and more preferably 1.34 to 1.30. By setting the refractive index of the low refractive index layer within the above range, an optical laminated film having an excellent balance between antireflection performance and scratch resistance can be obtained.
In the present invention, the thickness of the low refractive index layer is 10 to 1000 nm, preferably 30 to 500 nm.

  The reflectance of the laminate of the present invention is usually 0.7% or less, preferably 0.5% or less. The reflectance can be obtained as a reflectance at a wavelength of 550 nm by measuring a reflection spectrum at a predetermined incident angle using a known spectrophotometer, for example.

  The antireflection laminate of the present invention is excellent in scratch resistance. The antireflection laminate of the present invention is preferably a test in which the surface of a high refractive index layer or a low refractive index layer formed on the resin layer is rubbed 10 times in a state where a load of 0.025 MPa is applied to steel wool ( Even after the steel wool test), no scratches are observed on the film surface by visual observation.

  In the antireflection laminate of the present invention, the change in the total light transmittance before and after the steel wool test is extremely small. Here, change rate of total light transmittance (%) = (change amount of total light transmittance before and after test) / (total light transmittance before test) × 100. The change rate of the total light transmittance is preferably 1% or less.

  The antireflection laminate of the present invention has a very small change in haze value before and after the steel wool test. Here, haze change rate (%) = (haze change amount before and after test) / (haze before test) × 100, the haze change rate of the antireflection laminate of the present invention is 15% or less. Preferably there is.

Adhesive By bonding the polarizer and the transparent protective layer with an adhesive, functions such as mechanical strength of the polarizing plate and prevention of contraction of the polarizer can be further improved. Examples of the material constituting the adhesive include polyester urethane resins, polyether urethane resins, polyisocyanate resins, polyolefin resins, resins having a hydrocarbon skeleton in the main chain, polyamide resins, acrylic resins, and polyester resins. Examples thereof include resins, vinyl chloride / vinyl acetate copolymers, chlorinated rubber, cyclized rubber, and modified products obtained by introducing polar groups into these polymers. Among these, a modified product of a resin having a hydrocarbon skeleton in the main chain and a modified product of a cyclized rubber can be suitably used.

  Examples of the resin having a hydrocarbon skeleton in the main chain include a polybutadiene skeleton or a resin having a polybutadiene skeleton hydrogenated to at least a part thereof, specifically, a polybutadiene resin, a hydrogenated polybutadiene resin, a styrene / butadiene / styrene. Examples thereof include a block copolymer (SBS copolymer), a hydrogenated product thereof (SEBS copolymer), and the like. Among these, a modified product of a hydrogenated product of a styrene / butadiene / styrene block copolymer can be suitably used.

  As a compound for introducing a polar group used for obtaining a modified product of a polymer, a carboxylic acid or a derivative thereof is preferable. For example, unsaturated carboxylic acids such as acrylic acid, methacrylic acid, maleic acid and fumaric acid; halides, amides, imides, anhydrides and esters of unsaturated carboxylic acids such as maleyl chloride, maleimide, maleic anhydride and citraconic anhydride And the like; and the like. Among these, a modified product with an unsaturated carboxylic acid or an unsaturated carboxylic acid anhydride is excellent in adhesion, and thus can be suitably used. Among the unsaturated carboxylic acids or anhydrides thereof, acrylic acid, methacrylic acid, maleic acid, and maleic anhydride are more preferable, and maleic acid and maleic anhydride are particularly preferable. These unsaturated carboxylic acids and the like can be modified by mixing two or more kinds.

Transparent resin layer (D)
In the present invention, the transparent protective layer (D) constituting the polarizing plate of the present invention preferably has a birefringent layer in the transparent protective layer (D) that is close to the polarizer. In particular, the transparent protective layer (D) has a birefringence, the retardation can be easily controlled, the retardation is not uneven, and the optical compensation is excellent. Polymer resin or cellulose having an alicyclic structure It is preferable that it is a film containing a resin.

  The alicyclic structure-containing polymer resin that can be used for the transparent protective layer (D) of the present invention has an alicyclic structure in the main chain and / or side chain, and has mechanical strength, heat resistance, etc. From the viewpoint, those containing an alicyclic structure in the main chain are preferred.

  Examples of the alicyclic structure of the polymer include a saturated alicyclic hydrocarbon (cycloalkane) structure and an unsaturated alicyclic hydrocarbon (cycloalkene) structure. From the viewpoint of mechanical strength and heat resistance, cycloalkane. A structure or a cycloalkene structure is preferable, and a cycloalkane structure is most preferable. The number of carbon atoms constituting the alicyclic structure is not particularly limited, but is usually 4 to 30, preferably 5 to 20, more preferably 5 to 15 in the mechanical strength, The properties of heat resistance and film formability are highly balanced and suitable. The proportion of the repeating unit containing the alicyclic structure in the alicyclic structure-containing polymer used in the present invention may be appropriately selected according to the purpose of use, but is preferably 30% by weight or more, Preferably it is 50% by weight or more, particularly preferably 70% by weight or more, and most preferably 90% by weight or more. It is preferable from the viewpoints of transparency and heat resistance of the film that the ratio of the repeating unit having an alicyclic structure in the polymer resin having an alicyclic structure is in this range.

Specifically, the polymer resin having an alicyclic structure includes (1) a norbornene polymer, (2) a monocyclic olefin polymer, (3) a cyclic conjugated diene polymer, and (4) vinyl. Examples thereof include alicyclic hydrocarbon polymers and hydrogenated products thereof. Among these, norbornene-based polymers are more preferable from the viewpoints of transparency and moldability.
Specific examples of the norbornene-based polymer include ring-opening polymers of norbornene-based monomers, ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization, and hydrogenated products thereof, norbornene-based polymers Examples include addition polymers of monomers and addition copolymers with other monomers copolymerizable with norbornene monomers. Among these, from the viewpoint of transparency, a ring-opening (co) polymer hydrogenated product of a norbornene-based monomer is most preferable.
The polymer resin having the alicyclic structure is selected from known polymers disclosed in, for example, Japanese Patent Application Laid-Open No. 2002-321302.

Among the norbornene polymers suitably used for the transparent protective layer (D) of the present invention, as a repeating unit, X: bicyclo [3.3.0] octane-2,4-diyl-ethylene structure and Y: tricyclo [4.3.0.1 ^2,5 ] decane-7,9-diyl-ethylene structure, and the content of these repeating units is 90% by weight based on the entire repeating units of the thermoplastic norbornene resin. % And the ratio of the content ratio of X and the content ratio of Y is preferably 100: 0 to 40:60 in terms of a weight ratio of X: Y. By using such a resin, it is possible to obtain an optical film that has no dimensional change in the long term and is excellent in stability of optical characteristics.

Examples of the monomer that gives a repeating unit having the structure of X by polymerization include norbornene-based monomers having a structure in which a 5-membered ring is bonded to a norbornene ring. More specifically, tricyclo [4.3.0. 1 ^2,5 ] deca-3,7-diene (common name: dicyclopentadiene) and its derivatives (having a substituent on the ring), 7,8-benzotricyclo [4.3.0.10 ^{, 5} ] Dec-3-en (common name: methanotetrahydrofluorene) and its derivatives.
As the monomer polymerized to provide the repeating units of the structure Y, tetracyclo [4.4.0.1 ^{2, 5.} 1 ^7,10 ] deca-3,7-diene (common name: tetracyclododecene) and derivatives thereof (those having a substituent in the ring).
Here, examples of the substituent include an alkyl group, an alkylene group, and a polar group. In addition, these substituents may be the same or different and a plurality may be bonded to the ring. Norbornene monomers can be used alone or in combination of two or more.

  Specifically, as means for obtaining such a norbornene-based polymer, a) a monomer that is polymerized to give a repeating unit of the structure of X and a monomer that is polymerized to give a repeating unit of the structure of Y A method of polymerizing by controlling the copolymerization ratio, and if necessary, hydrogenating unsaturated bonds in the polymer; b) having a polymer having the X structure as a repeating unit, and having the Y structure as a repeating unit The method of controlling by the blend ratio with a polymer is mentioned.

  The molecular weight of the alicyclic structure-containing polymer resin that can be used in the present invention is gel permeation chromatography (hereinafter referred to as “GPC”) using cyclohexane (toluene when the polymer resin is not dissolved) as a solvent. The weight average molecular weight (Mw) in terms of polyisoprene or polystyrene measured in step) is usually 8,000 to 100,000, preferably 10,000 to 80,000, more preferably 15,000 to 50,000. It is. When the weight average molecular weight is in such a range, the mechanical strength and moldability of the film are highly balanced and suitable.

  The molecular weight distribution (weight average molecular weight (Mw) / number average molecular weight (Mn)) of the alicyclic structure-containing polymer resin used in the present invention is not particularly limited, but is usually 1.0 to 10.0, preferably 1.0. It is -4.0, More preferably, it is the range of 1.2-3.5.

  The alicyclic structure-containing polymer resin of the present invention may contain other compounding agents. The compounding agent is not particularly limited, but is a layered crystal compound; inorganic fine particles; antioxidants, heat stabilizers, light stabilizers, weathering stabilizers, ultraviolet absorbers, near infrared absorbers and other stabilizers; lubricants, plastics Resin modifiers such as agents; Colorants such as dyes and pigments; Antistatic agents and the like. These compounding agents can be used alone or in combination of two or more, and the compounding amount is appropriately selected within a range not impairing the object of the present invention.

  Examples of the antioxidant include phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, etc. Among them, phenolic antioxidants, particularly alkyl-substituted phenolic antioxidants are preferable. By blending these antioxidants, film coloring and strength reduction due to oxidative degradation during film formation can be prevented without lowering transparency, low water absorption and the like. These antioxidants can be used alone or in combination of two or more, and the blending amount thereof is appropriately selected within a range not impairing the object of the present invention, but is an amorphous thermoplastic resin. The amount is usually 0.001 to 5 parts by weight, preferably 0.01 to 1 part by weight per 100 parts by weight.

Examples of the material constituting the transparent protective layer (D) in the present invention include ethylene-vinyl alcohol copolymer and cellulose ester. Examples of the acetylated cellulose ester include diacetyl cellulose and triacetyl cellulose. Of these, triacetylcellulose (TAC) is most preferable from the viewpoints of transparency, mechanical strength, and the like. The thickness of the transparent protective layer (D) is preferably 30 to 150 μm, more preferably 40 to 100 μm. When the thickness of the transparent protective layer (D) is less than 20 μm, the mechanical strength of the laminate is lowered, and when it exceeds 200 μm, warpage or the like tends to occur when the laminate is placed in a high temperature and high humidity environment. The transmittance is also reduced. Therefore, when the thickness of the transparent protective layer (D) is in the above range, a laminate excellent in durability, mechanical strength and optical performance can be obtained. The moisture permeability of the further the transparent protective layer (D) is preferably 100~1,000g ^/ m 2 · 24h, more preferably 150~800g ^/ m 2 · 24h. If the moisture permeability is too low, drying of the adhesive for bonding the transparent protective layer (D) to the polarizer becomes insufficient, and if the moisture permeability is too high, the polarizing film absorbs moisture in the usage environment. Therefore, when the moisture permeability is in the above range, the reliability when the laminate is used as a polarizer protective film is improved.
The transparent protective layer (D) is subjected to alkali saponification treatment, plasma treatment, glow discharge treatment, corona discharge treatment, high frequency treatment, electron beam treatment, etc. in order to improve the adhesion to the polarizer. It doesn't matter.

  As the layer having birefringence, an appropriate layer showing a phase difference due to birefringence can be used. For example, those obtained by imparting birefringence to a transparent resin layer by stretching treatment, or those obtained by orienting an anisotropic material such as a liquid crystal polymer on an alignment film of a liquid crystal polymer or an alignment film of a transparent resin layer It is done. In particular, the transparent resin layer is preferably provided with birefringence by stretching treatment or the like.

  The alignment treatment for imparting birefringence to the transparent resin layer can be performed by an appropriate method such as a uniaxial stretching treatment or a biaxial stretching treatment using a free end or a fixed end. In the present invention, a film oriented in the thickness direction, or a film in which the direction of the main refractive index in the thickness direction is inclined with respect to the normal direction of the film can also be used as the birefringent layer.

The polarizing plate of this invention is arrange | positioned at the visual recognition side of a liquid crystal display device. The liquid crystal display device can be formed as a liquid crystal display device having an appropriate structure according to the prior art, such as a transmission type or a reflection type in which a polarizing plate is arranged on one side or both sides of a liquid crystal cell, or a transmission / reflection type. . In the present invention, it is necessary to select and form a transparent resin film that has been subjected to an orientation treatment for imparting birefringence according to the liquid crystal mode used in the liquid crystal cell.
Liquid crystal modes used in the liquid crystal cell include in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous spin wheel alignment (CPA) mode, and twisted nematic (TN) mode. , Super twisted nematic (STN) mode, hybrid alignment nematic (HAN) mode, and optically compensated bend (OCB) mode.

A plate having a layer exhibiting birefringence can be used as the transparent protective layer (D). It functions as a broadband quarter-wave plate, a uniaxial retardation plate, and a biaxial retardation plate.
The broadband 1/4 phase difference plate refers to a quarter wavelength plate whose phase difference is almost ¼ wavelength over the entire visible light region including wavelengths of 410 to 660 nm. Specific examples of the broadband quarter wave plate include norbornene on both sides of a layer made of a material having a negative intrinsic birefringence value such as a laminate of a half wave plate and a quarter wave plate or polystyrene resin. And a stretched laminate in which layers made of a material having a positive intrinsic birefringence such as a resin are laminated.

Examples of the resin having a negative intrinsic birefringence value include vinyl aromatic polymers, polyacrylonitrile polymers, polymethyl methacrylate polymers, cellulose ester polymers, and multicomponent copolymers thereof. . These resins having a negative intrinsic birefringence value can be sequentially selected according to the liquid crystal mode described later, and it may be preferable to use one kind alone, or two or more kinds may be used in combination. May be preferred.
Among these, as the resin having a negative intrinsic birefringence value, a vinyl aromatic polymer, a polyacrylonitrile polymer, and a polymethyl methacrylate polymer can be suitably used, and the vinyl aromatic polymer is Since it exhibits high birefringence, it can be used particularly suitably.

  Examples of the vinyl aromatic polymer include polystyrene; styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-chlorostyrene, p-nitrostyrene, p-aminostyrene, p-carboxystyrene, p-phenylstyrene, p-methoxystyrene, pt-butoxystyrene, etc., ethylene, propylene, butene, butadiene, isoprene, (meth) acrylonitrile, α-chloroacrylonitrile, methyl (meth) acrylate And a copolymer with ethyl (meth) acrylate, (meth) acrylic acid, maleic anhydride, maleimide, vinyl acetate, vinyl chloride, and the like. Among these, polystyrene and a copolymer of styrene and maleic anhydride can be suitably used.

Examples of the uniaxial retardation plate include a C plate and an A plate.
The C plate is a retardation layer having no or very small retardation in the plane and having a retardation only in the thickness direction, and the optical axis exists in the thickness direction perpendicular to the in-plane direction. The C plate is referred to as a positive C plate when its optical characteristic condition satisfies the following formula (1), and is referred to as a negative C plate when the following formula (2) is satisfied.
The following nx, ny, and nz represent the refractive indexes in the X-axis, Y-axis, and Z-axis directions in the retardation plate or the like, and the X-axis direction has the maximum refractive index in the plane of the layer. Direction (in-plane slow axis direction), and the Y-axis direction is a direction (in-plane fast axis direction) perpendicular to the X-axis direction in the plane of the layer, and the Z-axis direction is , The thickness direction of the layer perpendicular to the X-axis direction and the Y-axis direction.
nx≈ny <nz (■)
nx≈ny> nz (■■)
The A plate is a retardation layer having no or very small retardation in the thickness direction and having a retardation only in the plane, and the optical axis exists in the in-plane direction. The A plate is called a positive A plate when its optical characteristics satisfy the following formula (3), and is called a negative A plate when the following formula (4) is satisfied.
nx> ny≈nz (■■■)
nx≈nz> ny (■ V)
Examples of the biaxial retardation plate include a positive biaxial retardation plate (nz>nx> ny) and a negative biaxial retardation plate (nx>ny> nz).
As a retardation plate having uniaxiality or a retardation plate having biaxiality, a film obtained by stretching a film made of a material having a positive intrinsic birefringence value, a material having a negative intrinsic birefringence value such as a polystyrene resin, etc. A layered product in which layers made of a material having a positive intrinsic birefringence, such as norbornene-based resin, are stretched on both sides of the layer, or a discotic liquid crystal aligned in parallel or perpendicularly to the surface. Can be mentioned.
The in-plane retardation Re of the layer exhibiting birefringence and Rth which is the retardation perpendicular to the surface may be appropriately adjusted according to the liquid crystal mode to be used.

The method for obtaining the polarizing plate of the present invention is not particularly limited, but the transparent protective layer (A), the hard coat layer (B), the low refractive index layer (C) and the like are directly on one side of the polarizer or through another layer. These layers are laminated, and a transparent protective layer (D) is laminated on the other surface of the polarizer. At the time of lamination, they can be bonded using an appropriate adhesive means such as an adhesive or a pressure-sensitive adhesive through the polymer layer. Examples of the adhesive or pressure-sensitive adhesive include acrylic, silicone, polyester, polyurethane, polyether, rubber, and the like. Among these, an acrylic type is preferable from the viewpoint of heat resistance and transparency.
When laminating the polarizer and the transparent protective layer (D), when the transparent protective layer has a birefringent layer, the transmission axis of the polarizer and the slow axis of the transparent protective layer (D) are parallel. Or it is preferable to laminate | stack so that it may orthogonally cross.

The present invention will be described in more detail with reference to examples, but the present invention is not limited to the following examples. Parts and% are based on weight unless otherwise specified.
Evaluation in this example is performed by the following method.
(1) Pencil hardness Measured according to JIS-K5400 with a load of 500 g.
(2) In-plane retardation Re
Measurement is performed using an automatic birefringence meter [Oji Scientific Instruments, KOBRA-21ADH].
(3) Refractive index high-speed spectroscopic ellipsometry (manufactured by JAWoollam, M-2000U) was used to measure the measurement wavelength from 400 to 1000 nm and the incident angles at 55, 65, and 75 degrees, respectively, and calculated from these measured values (4 ) Tensile strength In accordance with JIS K7127, “Tensilon UTM-10T-PL” manufactured by Toyo Bald Wien Co., Ltd., the shape of the test piece is W = 10 mm, L = 40 mm, the tensile speed is 500 mm / min, load Measures with a load cell of 50 kgf. In addition, the same measurement is performed 5 times and the arithmetic average value is set as the representative value of the tensile strength.
(5) Based on haze ASTM D1003, it is measured using “turbidimeter NDH-300A” manufactured by Nippon Denshoku Industries Co., Ltd. In addition, the same measurement is performed 5 times and the arithmetic average value is used as the representative value of the total light transmittance and haze. Until the thickness is about 300 μm, the film thickness and the haze value are in a proportional relationship.
(6) Reflectance (%)
Using a spectrophotometer (manufactured by JASCO, UV-visible near-infrared spectrophotometer V-570, the reflection spectrum was measured at an incident angle of 5 degrees, and the reflectance at a wavelength of 550 nm was determined.
(7) The operation of bending a polarizing plate having a mechanical strength of 300 mm square on both sides along a diagonal line was repeated 500 times alternately, and the film was checked for microcracks with an optical microscope and evaluated as follows.
○: No change Δ: Slight microcracks are generated at the film edge, but there is no practical problem.
×: Microcracks are generated along the bent part (8)
In a state where a load of 0.025 MPa was applied to steel wool # 0000, the surface of the high refractive index layer or the low refractive index layer formed on the support was rubbed 10 times, and then the microscope observation was performed. There should be no scratches on the surface.
○: No scratches Δ: Slight scratches ×: Many conspicuous scratches (9) Evaluation of display performance A liquid crystal cell of a commercially available liquid crystal television (Sharp Corporation, LC-13C5-S) (Hitachi, Ltd., TX80D12VC0CAB) is sandwiched The polarizing plate and the viewing angle compensation film are peeled off, and instead, the optical laminate is bonded to the liquid crystal cell to obtain a monitor for evaluation. Then, a black background is displayed, and color unevenness and luminance unevenness from 45 degrees from the front direction and from the top, bottom, left, and right are visually confirmed. In addition, white characters are displayed with a black background, and the angle at which the characters do not change is measured when the line of sight is moved up, down, left, and right from the front.

(Production Example 1) Production of transparent protective layer D Pellets of norbornene polymer (product name “ZEONOR 1420R”, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature 136 ° C., saturated water absorption of less than 0.01% by weight) It dried for 4 hours at 110 degreeC using the distribute | circulated hot air dryer. And this pellet was coated with a coat hanger type T-die with a lip width of 650 mm with an average surface height Ra = 0.05 μm and a chrome-plated tip of the die lip provided with a leaf disk-shaped polymer filter (filtration accuracy 30 μm). A long transparent protective layer D having a width of 600 mm was obtained by melt extrusion at 260 ° C. using a short-shaft extruder.
The obtained long transparent protective layer D had a volatile component content of 0.012% by weight and a saturated water absorption of 0.015% by weight. Moreover, the film thickness of this transparent protective layer D was 40 micrometers. The in-plane retardation Re value was 3 nm.

(Production Example 2) Preparation of coating solution for hard coat layer Antimony pentoxide fine particle 40% methyl isobutyl ketone (referred to as “MIBK”) solution (average particle size 20 nm: on the antimony atoms where hydroxyl groups appear on the surface of the pyrochlore structure) 100 parts of UV curable urethane acrylate purple light UV7000B (manufactured by Nippon Synthetic Chemical Co., Ltd.), 10 parts of photoinitiator Irgacure-184 (manufactured by Ciba Geigy), A UV curable hard coat layer coating solution was prepared.

(Production Example 3) Preparation of Adhesive Solution 2 parts of a hydrogenated maleic anhydride-modified styrene / butadiene / styrene block copolymer (Asahi Kasei Co., Ltd., Tuftec M1913) was mixed with 8 parts of xylene and 40 parts of methyl isobutyl ketone. It melt | dissolved in the solvent and filtered the filter made from polytetrafluoroethylene with a hole diameter of 1 micrometer, and it was set as the adhesive agent solution.

(Production Example 4) Preparation of coating solution for low refractive index layer (C) Tetramethoxysilane oligomer ("Methyl silicate 51" manufactured by Colcoat Co.), methanol, water, and hydrochloric acid aqueous solution of 0.01N in a mass ratio of 21: The mixture was mixed at 36: 2: 2 and stirred in a high-temperature bath at 25 ° C. for 2 hours to cause the oligomer to undergo condensation polymerization to adjust the weight average molecular weight to 850, thereby obtaining a silicone resin.
Next, hollow silica isopropanol dispersion sol (manufactured by Catalyst Kasei Kogyo Co., Ltd., solid content 20% by weight, average primary particle diameter of about 35 nm, outer shell thickness of about 8 nm) prepared as an airgel method as hollow silica fine particles is added to the silicone resin, A fine refractive index / silicone resin (condensed compound equivalent) is blended so that the weight ratio is 8: 2 based on the solid content, and then diluted with methanol so that the total solid content becomes 1%. Was prepared.

[Example 1]
A polyester film is used as a transparent protective layer (Cosmo Shine: A4100 thickness 50 μm, manufactured by Toyobo Co., Ltd.) A high-frequency transmitter (Corona Generator HV05-2, manufactured by Tamtec) is used on both sides of a film having a haze of 0.5, a pencil hardness of H, and a strength of 16 MPa. Using a wire electrode with a diameter of 1.2 mm, an output voltage of 100%, an output of 250 W, an electrode length of 240 mm, and a workpiece electrode of 1.5 mm, a corona discharge treatment was performed for 3 seconds, and the surface tension was 0.072 N / m. The surface was modified so that a transparent protective layer A1 was obtained.
The adhesive solution obtained in Production Example 3 was applied to one surface of the surface-modified transparent resin layer A1 using a die coater and dried in a drying furnace at 80 ° C. for 5 minutes. The film thickness of the adhesive layer after drying was 0.5 μm. As a result, a transparent resin layer A1 having an adhesive layer was obtained.
The hard coat layer coating liquid obtained in Production Example 2 was continuously applied to the surface having the adhesive layer of the transparent resin layer A1 having the adhesive layer using a die coater. Next, after drying at 80 ° C. for 5 minutes, ultraviolet irradiation (integrated light amount 300 mJ / c ■) was performed to cure the coating solution, and a hard coat layer B1 was laminated. The film thickness of the hard coat layer (B) after curing was 5 μm. Further, the surface resistance value on this hard coat layer was 1 × 10 ⁹ Ω / cm.

The preparation liquid that was allowed to stand for 1 hour after the preparation of the coating liquid for the low refractive index layer was applied on the hard coat layer with a wire bar coater to form a coating film having a thickness of about 100 nm, and was further left for 1 hour to dry. Later, the film was heat-treated at 120 ° C. for 10 minutes in an oxygen atmosphere to obtain a laminated film C1 on which a low refractive layer having a thickness of 7 μm was formed.
A 75 μm-thick PVA film (Kurarayvinilon # 7500) was attached to the chuck and immersed in an aqueous solution of 0.2 g / l iodine and 60 g / l potassium iodide at 30 ° C. for 240 seconds, and then boric acid 70 g / l. Then, it was immersed in an aqueous solution having a composition of 30 g / l of potassium iodide and simultaneously subjected to boric acid treatment for 5 minutes while being uniaxially stretched 6.0 times. Finally, it was dried at room temperature for 24 hours to produce a polarizer. The degree of polarization was 99.995%.
A laminated film C1 is bonded to a polarizer via an acrylic adhesive (manufactured by Sumitomo 3M, “DP-8005 clear”), and an acrylic adhesive (manufactured by Sumitomo 3M, “DP” is attached to the other surface of the polarizer. -8005 clear ") to obtain a polarizing plate by bonding to the transparent protective layer D1 subjected to the surface modification treatment. Table 1 shows the evaluation results of the optical characteristics.

[Example 2]
As in Example 1, except that a 40 μm thick triacetylcellulose (TAC) film (manufactured by Konica Minolta, KC 4UX2M) having a haze of 0.5, a pencil hardness of HB, and a strength of 16 MPa was used as the transparent protective layer (D). Thus, a polarizing plate on which an antireflection layer was formed was obtained. Table 1 shows the evaluation results of the optical characteristics.

[Example 3]
As the transparent protective layer (A), a polyethylene terephthalate (PET) film having a thickness of 40 μm (Toyobo Ester Film Cosmo Shine A4300 thickness 50 μm) was used in the same manner as in Example 1 except that a film having a haze of 0.6, a pencil hardness of H, and a strength of 18 MPa was used. Thus, a polarizing plate on which an antireflection layer was formed was obtained. Table 1 shows the evaluation results of the optical characteristics.

[Comparative Example 1]
Example except that a 40 μm thick triacetylcellulose (TAC) film (manufactured by Konica Minolta ■, KC 4UX2M) having a haze of 0.5, a pencil hardness of HB and a strength of 16 MPa is used as the transparent protective layer (A) of 40 μm in thickness A polarizing plate on which an antireflection layer was formed was obtained in the same manner as in Example 1, but the antireflection layer was not laminated. Table 1 shows the evaluation results of the optical characteristics.

[Comparative Example 2]
A polarizing plate was obtained in the same manner as in Example 1, except that a polyester film (Toyobo Ester Film E5001 thickness 50 μm) having a haze of 2.2, a pencil hardness of H, and a strength of 18 MPa was used as the transparent protective layer (A). Table 1 shows the evaluation results of the optical characteristics.

(Production Example 5) Production of MVA retardation plate The retardation film used in the present invention is a norbornene polymer (product name “ZEONOR 1420R”, manufactured by Nippon Zeon Co., Ltd .; glass transition temperature 136 ° C., saturated water absorption 0.01). This was carried out using an original film having a thickness of less than 100% by weight.
Therefore, the above-described liquid crystal mode was sequentially adjusted. Examples of the biaxial stretching method include a method of sequentially biaxial stretching in the vertical direction and the horizontal direction, and a method of biaxial stretching in the vertical direction and the horizontal direction at the same time. In particular, the method was simultaneously biaxially stretched in that the process can be simplified, the stretched film is difficult to break, and the retardation value Rth in the thickness direction can be increased as an embodiment of the present invention. In the present invention, the raw film was formed by biaxial stretching at a stretching ratio of 1.3 in both the longitudinal direction and the transverse direction.
Using a coaxial biaxial stretching machine, the raw film 1 is heated at an oven temperature (preheating temperature, stretching temperature, heat setting temperature) of 136 ° C., a film feeding speed of 1 m / min, a chuck moving accuracy within ± 1%, and a longitudinal stretching ratio. Simultaneous biaxial stretching is performed at 1.41 times and a transverse stretching ratio of 1.41 times, and both end portions are cut off by 60 mm, and a stretched film 1 having a thickness of 89 μm and a width of 350 mm (hereinafter referred to as “optical compensation film 1”). Got. Re of the optical compensation film 1 was 20 nm, and Rth was 300 nm.

(Production Example 6) Production of IPS retardation plate A retardation plate was produced using polystyrene as a resin having a negative intrinsic birefringence value. Polystyrene is weak in film strength. In the present invention, an alicyclic structure-containing resin (Nippon Zeon Co., Ltd., ZEONOR 1020, glass transition temperature 105 ° C.) is used as a transparent resin that forms a substantially non-oriented layer. A layer consisting of styrene-maleic anhydride copolymer [Nova Chemical Japan Co., Ltd., Dilark D332, glass transition temperature 130 ° C., oligomer component content 3% by weight] It has a d layer composed of a combination [Mitsubishi Chemical Corporation, Modic AP F534A, Vicat softening point 55 ° C.], b layer (20 μm) -d layer (5 μm) -a layer (60 μm) -d layer (5 μm) An unstretched laminate of -b layer (20 μm) was obtained by coextrusion molding.
This unstretched laminate was longitudinally uniaxially stretched by a nip roll at a stretching temperature of 136 ° C., a stretching speed of 120% / min, and a stretching ratio of 1.2 times. From the styrene-maleic anhydride copolymer having a negative intrinsic birefringence value, An optical compensation film laminate having a thickness of 100 μm in which a substantially non-oriented layer made of a transparent norbornene-based polymer is laminated on both sides of a layer made of a modified ethylene-vinyl acetate copolymer via a layer made of Obtained.
The in-plane retardation measured with a light beam having a wavelength of 550 nm of the layer A of the obtained optical laminate was 120 nm, and the total of the in-plane retardations measured with light beams having a wavelength of 550 nm of the two layer B was 0 nm. In-plane retardations at wavelengths of 450 nm, 550 nm, and 650 nm were 148 nm, 120 nm, and 110 nm, respectively. The refractive index Σnz = 1.5800 in the thickness direction measured with a light beam having a wavelength of 550 nm of the optical laminate, and the refractive index measured with a light beam with a wavelength of 550 nm in two directions perpendicular to the thickness direction is Σnx = 1. 5788 and Σny = 1.5800. The thickness unevenness of the A layer was 1.0% with respect to the average thickness of the A layer.

Example 4 (Production of liquid crystal display device)
The transparent protective layer (D) portion of the polarizing plate laminated in Example 1 was replaced with the MVA retardation plate prepared in Production Example 5, and the liquid crystal of a commercially available liquid crystal television (manufactured by Sharp Corporation, LC-13C5-S). The polarizing plate and the viewing angle compensation film sandwiching the cell are peeled off, and instead the optical laminate is bonded to the liquid crystal cell to obtain an evaluation monitor. Then, color unevenness and luminance unevenness from the front direction and 45 degrees from the top, bottom, left, and right when the background is displayed in black are visually confirmed. In addition, white characters were displayed with a black background, and the angle at which the characters could not be seen when the line of sight was moved up and down and left and right from the front was measured. The results are shown in Table 2.

[Example 5] (Production of liquid crystal display device)
Except that the part of the transparent protective film (D) of the polarizing plate laminated in Example 1 was replaced with the transparent protective layer 1A (substantially non-oriented and the Re value was 3 nm) prepared in Production Example 1. Measurement was performed in the same manner as in No. 4. The results are shown in Table 2.

[Comparative Example 3] (Production of liquid crystal display device)
The transparent protective layer (D) of the polarizing plate laminated in Example 1 was used as the transparent protective layer A prepared in Production Example 1 as a polyester film (Toyobo Ester Film E5001 thickness 50 μm) haze 2.2, pencil hardness H, The measurement was performed in the same manner as in Example 4 except that a film having a strength of 18 MPa was used. The results are shown in Table 2.

[Example 6] (Production of liquid crystal display device)
The part of the transparent protective film (D) of the polarizing plate laminated in Example 1 was replaced with the retardation plate for IPS prepared in Production Example 6 and measured. The results are shown in Table 2.

[Example 7] (Production of liquid crystal display device)
Except that the part of the transparent protective film (D) of the polarizing plate laminated in Example 1 was replaced with the transparent protective layer 1A prepared in Production Example 1 (substantially non-oriented and the Re value was 3 nm). Measurement was performed in the same manner as in No. 4. The results are shown in Table 2.

[Comparative Example 4] (Creation of liquid crystal display device)
The transparent protective layer (D) of the polarizing plate laminated in Example 1 was used as the transparent protective layer A prepared in Production Example 1 as a polyester film (Toyobo Ester Film Cosmo Shine E5001 thickness 50 μm) haze 2.2, pencil hardness. The measurement was performed in the same manner as in Example 4 except that a film having H and a strength of 18 MPa was used. The results are shown in Table 2.

From the results in Table 1, the following can be understood.
As shown in the examples, the polarizing plate of the present invention is a polarizing plate having specific properties and excellent in all of transparency, mechanical strength, antireflection performance, scratch resistance, and adhesion by using PET. It can be seen that it can be formed.
On the other hand, as shown in the comparative example, when PET having a high haze is used as the transparent protective film, the pencil hardness is increased, but the light transmittance, the haze of the polarizing plate is deteriorated, the visibility is deteriorated, and triacetyl is used. It can be seen that there is a problem in scratch resistance when cellulose (TAC) is used.
When a liquid crystal display device was produced and the viewing angle was measured in accordance with various liquid crystal modes, it was found that the retardation plate of the present invention had improved viewing angle characteristics. Moreover, in the comparative example, the viewing angle was measured, but it was also confirmed that the brightness was lowered in addition to the viewing angle reduction as a whole.

FIG. 1 is a schematic diagram showing a panel configuration of a liquid crystal display device. FIG. 2 is a schematic view of the polarizing plate of the present invention.

Explanation of symbols

1: Low refractive index layer and hard coat laminate. 2: A polarizer. 3: A retardation plate. 4: A liquid crystal cell. 5: Retardation plate. 6: A polarizing plate.
7: Transparent protective layer (D). 8: A polarizer. 9: Hard coat layer. 10: Low refractive index layer.

Claims (6)

At least a transparent protective layer (A), a hard coat layer (B), and a low refractive index layer (C) are laminated in this order on one surface of the polarizer, and a transparent protective layer (D ) Is laminated, the transparent protective layer (A) is a film containing a polyester resin having a haze value of 1.0 or less at a thickness of 50 μm,
A polarizing plate characterized in that the surface hardness on the (A) side is H or more in pencil hardness. The polarizing plate according to claim 1, wherein the refractive index of the low refractive index layer (C) is 1.36 or less. The polarizing plate according to claim 1, wherein the low refractive index layer (C) is a layer containing an airgel made of silicon oxide. The polarizing plate according to any one of claims 1 to 3, wherein the transparent protective layer (D) is a polymer resin having an alicyclic structure or a cellulose resin. The polarizing plate according to claim 1, wherein the transparent protective layer (D) is a layer having a retardation. The liquid crystal display device formed by arrange | positioning the transparent protective layer (A) side of the polarizing plate in any one of Claims 1-6 in the visual recognition side.

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