TWI764913B - Polarizing plate - Google Patents

Abstract

An object of the present is to provide a polarizing plate in which crack (broken piece) of a polarizing film hardly occurs due to thermal shock.

A solution for resolving the object is to provide a polarizing plate comprising a first thermoplastic resin film, a first adhesive layer and a polarizing film in this order, wherein the product of the rigidity represented by R_1t × R_1a ×R_p is 5.0 × 10^-8 [(MPa ． mm³)³] or more, provided that the rigidity of the first thermoplastic resin film is R_1t [MPa · mm³], the rigidity of the first adhesive layer is R_1a [MPa · mm³], and the rigidity of the polarizing film is R_p [MPa · mm³]. The rigidity R_1t is (the tensile elastic modulus at 80 ℃ of the first thermoplastic resin film [MPa]) × (the thickness of the first thermoplastic resin film [mm])³; The rigidity R_1a is (the storage elastic modulus at 80℃ of the first adhesive layer [MPa]) × (the thickness of the first adhesive layer [mm])³; and the rigidity R_p is (the tensile elastic modulus at 80℃ in the transmission axis direction of the polarizing film [MPa]) × (the thickness of the polarizing film [mm])³.

Description

polarizer

The present invention relates to polarizing plates.

In general, a polarizing plate has a configuration in which a protective film made of a thermoplastic resin is bonded to one side or both sides of a polarizing film through an adhesive. Since the polarizing film is generally a film obtained by extending a film made of a polyvinyl alcohol-based resin or the like at a high draw ratio, the resistance to cracking or cracking (cracking) is relatively low. By laminating the protective film, the durability of the polarizing film is improved, but even so, the polarizing film is prone to cracks and the like.

Cracks in the polarizing film not only occur when the polarizing film containing the polarizing film is subjected to mechanical shock, such as cutting the polarizing film (Patent Document 1), but also may be caused by the surrounding environment exposed to the polarizing film during use. A sudden temperature change (thermal shock) occurs (Patent Document 2).

[Prior Art Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2004-029367

[Patent Document 2] Japanese Patent Laid-Open No. 2012-145645

An object of the present invention is to provide a polarizing plate that is less prone to cracks (cracks) of the polarizing film due to thermal shock.

The present invention provides the polarizing plate shown below.

[1] A polarizing plate comprising a first thermoplastic resin film, a first adhesive layer, and a polarizing film in this order, wherein the rigidity of the first thermoplastic resin film is R _1t [MPa·mm ³ ], and When the rigidity of the first adhesive layer is set to R _1a [MPa·mm ³ ], and the rigidity of the polarizing film is set to R _p [MPa·mm ³ ], the product of the rigidity represented by the following formula (I) 5.0×10 ⁻⁸ (MPa·mm ³ ) ³ or more: Product of rigidity=R _1t ×R _1a ×R _p (I), where rigidity R _1t is represented by the following formula (Ia): rigidity R _1t =(tensile modulus of elasticity of the first thermoplastic resin film at 80°C [MPa])×(thickness of the first thermoplastic resin film [mm]) ³ (Ia), the rigidity R _1a is represented by the following formula (Ib) Representation: rigidity R _1a =(storage modulus of elasticity of the first adhesive layer at 80°C [MPa])×(thickness of the first adhesive layer [mm]) ³ (Ib), the rigidity R _p is represented by the following formula (Ic) represents: rigidity R _p = (tensile elastic modulus [MPa] of the transmission axis direction of the polarizing film at 80° C.)×(thickness [mm] of the polarizing film) ³ (Ic).

[2] The polarizing plate according to [1], wherein the first adhesive layer is a cured product layer of an active energy ray-curable adhesive.

[3] The polarizing plate according to [2], wherein the active energy ray-curable adhesive contains a cation-curable component.

[4] The polarizing plate according to any one of [1] to [3], wherein the first thermoplastic resin film is made of a polyester-based resin, a polycarbonate-based resin, a polyolefin-based resin, ( Meth) acrylic resins and cellulose ester resins are composed of thermoplastic resins.

[5] The polarizing plate according to any one of [1] to [4], comprising the first thermoplastic resin film, the first adhesive layer, the polarizing film, the second adhesive layer, and The second thermoplastic resin film.

[6] The polarizing plate according to [5], wherein the rigidity of the second adhesive layer is R _2a [MPa·mm ³ ], and the rigidity of the second thermoplastic resin film is R _2t [ MPa·mm ³ ], the product of rigidity represented by the following formula (II) is 5.0×10 ^-8 (MPa·mm ³ ) ³ or more: product of rigidity=R _p ×R _2a ×R _2t (II), Here, rigidity R _2a is represented by the following formula (IIa): rigidity R _2a =(storage modulus of elasticity of the second adhesive layer at 80° C. [MPa])×(thickness of the second adhesive layer [mm] ]) ³ (IIa), the rigidity R _2t is represented by the following formula (IIb): Rigidity R _2t = (the tensile modulus of elasticity of the second thermoplastic resin film at 80° C. [MPa]) × (the second thermoplastic resin film thickness [mm]) ³ (IIb).

[7] The polarizing plate according to [5] or [6], wherein the second adhesive layer is a cured product layer of an active energy ray-curable adhesive.

[8] The polarizing plate according to [7], wherein the active energy ray-curable adhesive contains a cation-curable component.

[9] The polarizing plate according to any one of [5] to [8], wherein the second thermoplastic resin film is made of a polyester-based resin, a polycarbonate-based resin, a polyolefin-based resin, ( Meth) acrylic resins and cellulose ester resins are composed of thermoplastic resins.

[10] The polarizing plate according to any one of [5] to [9], wherein the first thermoplastic resin film is made of a (meth)acrylic resin, and the second thermoplastic resin film is made of a polymer It consists of olefin resin or cellulose ester resin.

[11] The polarizing plate according to any one of [5] to [9], wherein both the first thermoplastic resin film and the second thermoplastic resin film are made of a (meth)acrylic resin.

[12] The polarizing plate according to any one of [5] to [11], wherein at least one of the first thermoplastic resin film and the second thermoplastic resin film is a retardation film.

ADVANTAGE OF THE INVENTION According to this invention, the polarizing plate which is hard to generate|occur|produce the crack (crack) of the polarizing film by thermal shock can be provided.

10‧‧‧Polarizing Film

15‧‧‧First Adhesive Layer

21‧‧‧The first thermoplastic resin film

22‧‧‧Second thermoplastic resin film

25‧‧‧Second Adhesive Layer

Fig. 1 is a schematic cross-sectional view showing an example of a polarizing plate according to the present invention.

Fig. 2 is a schematic cross-sectional view showing another example of the polarizing plate according to the present invention.

Hereinafter, the present invention will be described in detail with reference to embodiments.

(1) The composition of the polarizing plate

Fig. 1 and Fig. 2 are schematic cross-sectional views showing an example of a polarizing plate according to the present invention. The polarizing plate according to the present invention includes the first thermoplastic resin film 21 , the first adhesive layer 15 , and the polarizing film 10 in this order. As shown in FIG. 1 , the polarizing plate may be composed of a first thermoplastic resin film 21 , a first adhesive layer 15 , and a polarizing film 10 . As shown in FIG. 2 , the polarizing plate may include a first thermoplastic resin film 21 , a first adhesive layer 15 , a polarizing film 10 , a second adhesive layer 25 and a second thermoplastic resin film 22 in this order.

Usually, the first thermoplastic resin film 21 is laminated in contact with the surface of the first adhesive layer 15 , and the first adhesive layer 15 is laminated in contact with the surface of the polarizing film 10 . In addition, generally, the second thermoplastic resin film 22 is laminated in contact with the surface of the second adhesive layer 25 , and the second adhesive layer 25 is laminated in contact with the surface of the polarizing film 10 .

The polarizing plate may further include other layers laminated on the first thermoplastic resin film 21 , the second thermoplastic resin film 22 , or the polarizing film 10 . As another layer, a retardation plate, a reflection layer, a transflective layer, a light-diffusion layer, a light collecting plate, a brightness enhancement film, an adhesive (pressure-sensitive adhesive) layer, etc. are mentioned, for example. The polarizing plate may have two or more other layers. The other layers can be laminated on the first thermoplastic resin film 21, the second thermoplastic resin film 22, or the polarizing film 10 using an adhesive or an adhesive. The other layers may also serve as the first thermoplastic resin film 21 or the second thermoplastic resin film 22 .

Among the adhesives constituting the adhesive layer, (meth)acrylic polymers, polysiloxane-based polymers, polyesters, polyurethanes, polyethers, and the like can be used as matrix polymers. Among these, it is preferable to select and use a (meth)acrylic adhesive, which has excellent optical transparency, maintains moderate wettability or cohesion, and is also excellent in adhesion to the substrate. Furthermore, it has weather resistance. Those that do not cause problems such as floating or peeling under heating or humidification. In the (meth)acrylic adhesive, an alkyl ester of (meth)acrylic acid having an alkyl group having a carbon number of 20 or less, such as methyl, ethyl, and butyl, is mixed with (meth)acrylic acid or (meth)acrylic acid. (Meth)acrylic monomers containing functional groups such as hydroxyethyl acrylate are prepared so that the glass transition temperature is preferably 25°C or lower, more preferably 0°C or lower, and the weight average molecular weight is 100,000 or more ( Meth)acrylic copolymers are useful as matrix polymers. In this specification, "(meth)acrylic" means at least one selected from the group consisting of acrylic and methacrylic. The same applies to "(meth)acrylate".

To form an adhesive layer on a polarizing plate, etc., for example, a coating solution can be prepared by dissolving or dispersing the adhesive composition in an organic solvent such as toluene or ethyl acetate and directly coating it on the polarizing plate, or It is performed by forming an adhesive layer on a release film in advance and transferring it to a polarizing plate. The thickness of the adhesive layer is determined according to the adhesive force, etc., and is preferably in the range of about 1 to 50 μm.

In the adhesive layer, fillers, pigments or colorants, antioxidants, ultraviolet absorbers, etc., composed of glass fibers or glass beads, resin beads, metal powders or other inorganic powders, etc., can also be formulated as required. Examples of the ultraviolet absorber include salicylate-based compounds, benzophenone-based compounds, benzotriazole-based compounds, cyanoacrylate-based compounds, nickel zirconium salt-based compounds, and the like.

(2) Product of rigidity

In the polarizing plate according to the present invention, the rigidity of the first thermoplastic resin film 21 is R _1t [MPa·mm ³ ], the rigidity of the first adhesive layer 15 is R _1a [MPa·mm ³ ], and the When the rigidity of the polarizing film 10 is set to R _p [MPa·mm ³ ], the product of rigidity represented by the following formula (I) is 5.0×10 ⁻⁸ (MPa·mm ³ ) ³ or more: Product of rigidity=R _1t ×R _1a ×R _p (I).

By setting the product of rigidity represented by the above formula (I) to be 5.0×10 ⁻⁸ (MPa·mm ³ ) ³ or more, cracks (cracks) of the polarizing film 10 due to thermal shock can be suppressed. From the viewpoint of more effectively suppressing cracks, the product of the rigidity represented by the above formula (I) is preferably 1.0×10 ^-7 (MPa·mm ³ ) ³ or more, more preferably 1.5×10 ^-7 (MPa ‧mm ³ ) ³ or more, more preferably 2.0×10 ^-7 (MPa‧mm ³ ) ³ or more. The product of rigidity represented by the above formula (I) is usually 5 × 10 ^-6 (MPa·mm ³ ) ³ or less, and is preferably 2 × 10 ^-6 (MPa·mm 3 ) from the viewpoint of thinning the polarizing plate and the like mm ³ ) ³ or less.

The rigidity R _1t of the first thermoplastic resin film 21 is represented by the following formula (Ia): rigidity R _1t =(tensile modulus of elasticity of the first thermoplastic resin film 21 at 80° C. [MPa])×(first thermoplastic resin The thickness of the film 21 [mm]) ³ (Ia).

The rigidity R _1a of the first adhesive layer 15 is represented by the following formula (Ib): rigidity R _1a =(storage modulus of elasticity of the first adhesive layer 15 at 80° C. [MPa])×(first adhesive layer 15 thickness [mm]) ³ (Ib).

The rigidity _Rp of the polarizing film 10 is represented by the following formula (Ic): Rigidity _Rp =(tensile modulus of elasticity at 80° C. in the transmission axis direction of the polarizing film 10 [MPa])×(thickness of the polarizing film 10 ) [mm]) ³ (Ic).

The methods of measuring the tensile modulus and thickness of each film, and the storage modulus and thickness of the first adhesive layer 15 are as described in the paragraphs of Examples described later.

The polarizing plate including the first thermoplastic resin film 21 , the first adhesive layer 15 , the polarizing film 10 , the second adhesive layer 25 and the second thermoplastic resin film 22 in this order suppresses cracking (breaking) of the polarizing film 10 . In other words, when the rigidity of the second adhesive layer 25 is set to R _2a [MPa·mm ³ ], and the rigidity of the second thermoplastic resin film 22 is set to R _2t [MPa·mm ³ ], it may be further satisfied The product of rigidity represented by the following formula (II) is 5.0×10 ⁻⁸ (MPa·mm ³ ) ³ or more: Product of rigidity=R _p ×R _2a ×R _2t (II).

From the viewpoint of suppressing cracks, the product of the rigidity represented by the above formula (II) is preferably 1.0×10 ^-7 (MPa·mm ³ ) ³ or more, more preferably 1.5×10 ^-7 (MPa·mm ³ ) ) ³ or more, more preferably 2.0×10 ^-7 (MPa·mm ³ ) ³ or more. The product of rigidity represented by the above formula (II) is usually 5 × 10 ^-6 (MPa·mm ³ ) ³ or less, and is preferably 2 × 10 ^-6 (MPa·mm 3 ) from the viewpoint of thinning the polarizing plate and the like mm ³ ) ³ or less.

The rigidity R _2a of the second adhesive layer 25 is represented by the following formula (IIa): rigidity R _2a =(storage modulus of elasticity of the second adhesive layer 25 at 80° C. [MPa])×(second adhesive layer 25 thickness [mm]) ³ (IIa).

The rigidity R _2t of the second thermoplastic resin film 22 is represented by the following formula (IIb): Rigidity R _2t = (tensile modulus of elasticity of the second thermoplastic resin film 22 at 80° C. [MPa])×(second thermoplastic resin Thickness of film 22 [mm]) ³ (IIb).

The storage elastic modulus and thickness of the second adhesive layer 25 and the tensile elastic modulus and thickness of the second thermoplastic resin film 22 are measured as described in the paragraph of Examples described later.

(3) Polarizing film

The polarizing film 10 may be obtained by adsorbing and aligning a dichroic dye to a uniaxially stretched polyvinyl alcohol-based resin film. As the polyvinyl alcohol-based resin constituting the polyvinyl alcohol-based resin film, one obtained by saponifying a polyvinyl acetate-based resin can be used. As the polyvinyl acetate-based resin, polyvinyl acetate, which is a homopolymer of vinyl acetate, can be exemplified, and other than these, there are copolymers of vinyl acetate and other monomers that can be copolymerized therewith. Examples of other monomers that can be copolymerized with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, and (meth)acrylamides having an ammonium group.

The degree of saponification of the polyvinyl alcohol-based resin may be in the range of 80.0 to 100.0 mol %, preferably 90.0 to 100.0 mol %, and more preferably 98.0 to 100.0 mol %. If the degree of saponification is less than 80.0 mol %, the water resistance and/or heat and humidity resistance of the polarizing plate may decrease.

The degree of saponification refers to the ratio of converting the acetate group (acetoxy group: -OCOCH ₃ ) contained in the polyvinyl acetate-based resin, which is the raw material of the polyvinyl alcohol-based resin, into a hydroxyl group by a unit ratio ( Molar %), which is defined by the following formula: degree of saponification (mol %)=100×(the number of hydroxyl groups)/(the number of hydroxyl groups+the number of acetate groups).

The degree of saponification can be determined according to JIS K 6726 (1994).

The average degree of polymerization of the polyvinyl alcohol-based resin is preferably from 100 to 10,000, more preferably from 1,500 to 8,000, and even more preferably from 2,000 to 5,000. The average degree of polymerization of the polyvinyl alcohol-based resin can also be determined in accordance with JIS K 6726 (1994). When the average degree of polymerization is less than 100, it is difficult to obtain favorable polarization performance, and when it exceeds 10,000, the solubility to the solvent deteriorates, and it may become difficult to form a polyvinyl alcohol-based resin film.

The dichroic dye contained in the polarizing film 10 (adsorption alignment) can be iodine or a dichroic organic dye. Specific examples of dichroic organic dyes include red BR, red LR, red R, pink LB, magenta BL, burgundy GS, sky blue LG, lemon yellow, blue BR, blue 2R, navy blue RY, green LG, violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR, Orange 3R, Scarlet GL, Scarlet KGL, Congo Red, Brilliant Violet BK, Supra Blue G, Supra Blue GL, Supra Orange GL, Direct Sky Blue, Direct Fast Orange S, Fast Black. A dichroic dye may be used individually by 1 type, and may use 2 or more types together. The dichroic pigment is preferably iodine.

The polarizing film 10 can be manufactured through the following steps: a step of uniaxially extending a polyvinyl alcohol-based resin film; a step of adsorbing the dichroic dye by dyeing the polyvinyl alcohol-based resin film with a dichroic dye ; The step of carrying out cross-linking treatment on the polyvinyl alcohol-based resin film adsorbed with the dichroic pigment; and the step of washing with water after the cross-linking treatment.

The polyvinyl alcohol-based resin film is obtained by film-forming the above-mentioned polyvinyl alcohol-based resin. The film-forming method is not particularly limited, and known methods such as melt extrusion and solvent casting can be employed.

The uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before, simultaneously with, or after the dyeing of the dichroic dye. In the case of performing uniaxial stretching after dyeing, this uniaxial stretching can also be performed before or during the cross-linking treatment. Furthermore, uniaxial stretching may also be performed in these plural stages.

In the case of uniaxial stretching, the uniaxial stretching can be performed between rolls with different peripheral speeds, and the uniaxial stretching can also be performed using a heat roll. In addition, the uniaxial stretching may be dry stretching in which the stretching is performed in the atmosphere, or wet stretching in which the polyvinyl alcohol-based resin film is stretched in a solution. The elongation ratio is usually about 3 to 8 times.

As a method of dyeing a polyvinyl alcohol-based resin film with a dichroic dye, for example, a method of immersing the polyvinyl alcohol-based resin film in an aqueous solution (dyeing solution) containing a dichroic dye is employed. The polyvinyl alcohol-based resin film is preferably subjected to water immersion treatment (swelling treatment) before dyeing treatment.

In the case of using iodine as a dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in an aqueous solution containing iodine and potassium iodide is usually employed. The content of iodine in the dyeing aqueous solution is usually 0.01 to 1 part by weight per 100 parts by weight of water. In addition, the content of potassium iodide is usually 0.5 to 20 parts by weight per 100 parts by weight of water. The temperature of the dyeing aqueous solution is usually about 20 to 40°C.

On the other hand, when a dichroic organic dye is used as a dichroic dye, a method of dyeing by immersing a polyvinyl alcohol-based resin film in a dyeing aqueous solution containing a water-soluble dichroic organic dye is generally employed. The content of the dichroic organic dye in the dyeing aqueous solution is usually 1×10 ^-4 to 10 parts by weight, preferably 1×10 ^-3 to 1 part by weight, per 100 parts by weight of water. The dyeing aqueous solution may also contain inorganic salts such as sodium sulfate as dyeing auxiliaries. The temperature of the dyeing aqueous solution is usually about 20 to 80°C.

The crosslinking treatment after dyeing with a dichroic dye can be performed by immersing the dyed polyvinyl alcohol-based resin film in an aqueous solution containing a crosslinking agent. A suitable example of the crosslinking agent is boric acid, and other crosslinking agents such as boron compounds such as borax, glyoxal, and glutaraldehyde can also be used. Only one type of crosslinking agent may be used, or two or more types may be used in combination.

The amount of the crosslinking agent in the aqueous solution containing the crosslinking agent is usually 2 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. In the case of using iodine as the dichroic dye, the aqueous solution containing the crosslinking agent preferably contains potassium iodide. The amount of potassium iodide in the aqueous solution containing the crosslinking agent is usually 0.1 to 15 parts by weight, preferably 5 to 12 parts by weight, per 100 parts by weight of water. The temperature of the aqueous solution containing the crosslinking agent is usually 50°C or higher, preferably 50 to 85°C.

The polyvinyl alcohol-based resin film after the cross-linking treatment is usually washed with water. The water washing treatment can be performed by, for example, immersing the cross-linked polyvinyl alcohol-based resin film in water. The temperature of the water in the water washing treatment is usually about 1 to 40°C.

After washing with water, drying treatment is performed to obtain the polarizing film 10 . The drying treatment may be drying by a hot air dryer, drying by contact with a hot roller, drying by a far-infrared heater, or the like. The temperature of the drying treatment is usually about 30 to 100°C, preferably 50 to 90°C.

The thickness of the polarizing film 10 is, for example, 2 to 50 μm. From the viewpoint of increasing the rigidity R _p of the polarizing film 10 , the thickness thereof is preferably 5 μm or more, more preferably 10 μm or more, and even more preferably 15 μm or more. From the viewpoint of thinning the polarizing plate and the like, the thickness of the polarizing film 10 is preferably 40 μm or less, and more preferably 30 μm or less.

From the viewpoint of increasing the rigidity R _p of the polarizing film 10 , the tensile modulus of elasticity at 80° C. in the transmission axis direction of the polarizing film 10 is preferably 3000 MPa or more, more preferably 4000 MPa or more. The tensile modulus of elasticity is usually 7000 MPa or less. The rigidity R _p of the polarizing film 10 is preferably 4500 MPa·mm ³ or more from the viewpoint of increasing the rigidity product represented by the above formula (I) and even the rigidity product represented by the above formula (II). From the viewpoint of thinning the polarizing plate, etc., the rigidity R _p is preferably 6500 MPa·mm ³ or less.

(4) Thermoplastic resin film

The thermoplastic resin constituting the first thermoplastic resin film 21 and the second thermoplastic resin film 22 may be, for example, a chain polyolefin-based resin (polypropylene-based resin, etc.), a cyclic polyolefin-based resin (norbornene-based resin, etc.), or the like. Polyolefin-based resins; Cellulose ester-based resins such as triacetyl cellulose, diacetyl cellulose; Polyester-based resins such as polyethylene terephthalate, polybutylene terephthalate, etc.; Polycarbonate Ester resin; (meth)acrylic resin such as methyl methacrylate resin; polystyrene resin; polyvinyl chloride resin; acrylonitrile/butadiene/styrene resin; acrylonitrile/styrene series resin; polyvinyl acetate series resin; polyvinylidene chloride series resin; polyamide series resin; polyacetal series resin; modified polyphenylene ether series resin; arylate resin; polyamide imide resin; polyimide resin, etc.

The thermoplastic resins constituting the first thermoplastic resin film 21 and the second thermoplastic resin film 22 are each preferably selected from polyester-based resins, polycarbonate-based resins, polyolefin-based resins, (meth)acrylic resins, and cellulose A thermoplastic resin of the group consisting of ester resins. The first thermoplastic resin film 21 and the second thermoplastic resin film 22 may each be a single-layer structure film containing one or more thermoplastic resins selected from the above-mentioned group, or may be made of different thermoplastic resins or the same thermoplastic resin A film with a multilayer structure composed of two or more layers of resin.

The polyester-based resin is a resin other than the above-mentioned cellulose ester-based resin having an ester bond, and is generally composed of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As a polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalene dicarboxylate. As a polyhydric alcohol, a dihydric glycol can be used, for example, ethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol, etc. are mentioned. Examples of suitable polyester-based resins include polyethylene terephthalate.

Polycarbonate resins are engineering plastics composed of polymers obtained by bonding monomer units through carbonate groups. They are resins with high impact resistance, heat resistance, flame retardancy and transparency. The polycarbonate-based resin may also be, for example, a resin called modified polycarbonate in which the polymer backbone is modified so as to reduce the photoelastic coefficient, or a copolymerized polycarbonate in which wavelength dependence is improved.

Examples of the chain polyolefin resin include homopolymers of chain olefins such as polyethylene resins and polypropylene resins, and there are also copolymers composed of two or more kinds of chain olefins. More specific examples include polypropylene-based resins (polypropylene resins that are homopolymers of propylene or copolymers mainly composed of propylene), polyethylene-based resins (polyethylene resins that are homopolymers of ethylene or ethylene-based resins) the copolymer).

Cyclic polyolefin-based resin is a general term for resins polymerized by cyclic olefins as polymerized units. Specific examples of cyclic polyolefin-based resins include ring-opening (co)polymers of cyclic olefins, addition polymers of cyclic olefins, and copolymers of cyclic olefins and linear olefins such as ethylene and propylene. (representatively, random copolymers), graft polymers obtained by modifying these with unsaturated carboxylic acids or derivatives thereof, and hydrides of these. Among these, it is preferable to use a norbornene-based resin using a norbornene-based monomer such as norbornene or a polycyclic norbornene-based monomer as a cyclic olefin.

The (meth)acrylic resin is not particularly limited, but is generally a polymer containing methacrylate as a main monomer, preferably a copolymer in which a small amount of other comonomer components are copolymerized. This copolymer is usually obtained by polymerizing a monofunctional monomer composition containing (meth)acrylates such as methyl methacrylate and methyl acrylate in the coexistence of a radical polymerization initiator and a chain transfer agent. In addition, the third monofunctional monomer may be copolymerized to the (meth)acrylic resin.

Examples of the third monofunctional monomer include ethyl methacrylate, butyl methacrylate, cyclohexyl methacrylate, phenyl methacrylate, benzyl methacrylate, and 2-ethyl methacrylate. Methacrylates other than methyl methacrylate such as hexyl ester and 2-hydroxyethyl methacrylate; ethyl acrylate, butyl acrylate, cyclohexyl acrylate, phenyl acrylate, benzyl acrylate, 2-ethyl acrylate Acrylates such as methylhexyl and 2-hydroxyethyl acrylate; methyl 2-(hydroxymethyl)acrylate, methyl 2-(1-hydroxyethyl)acrylate, ethyl 2-(hydroxymethyl)acrylate and Hydroxyalkyl acrylates such as butyl 2-(hydroxymethyl)acrylate; unsaturated acids such as methacrylic acid and acrylic acid; halogenated styrenes such as chlorostyrene and bromostyrene; vinyltoluene and α-methylstyrene substituted styrenes; unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated acid anhydrides such as maleic anhydride and citraconic anhydride; phenylmaleimide and cyclohexylmaleimide, etc. Unsaturated imides. Only one type of the third monofunctional monomer may be used alone, or a plurality of different types may be used in combination.

Polyfunctional monomers can also be copolymerized to the (meth)acrylic resin. Examples of polyfunctional monomers include ethylene glycol di(meth)acrylate, diethylene glycol di(meth)acrylate, triethylene glycol di(meth)acrylate, and tetraethylene glycol di(meth)acrylate. (Meth)acrylate, nonaethylene glycol di(meth)acrylate, tetradecylethylene glycol di(meth)acrylate, etc., the two terminal hydroxyl groups of ethylene glycol or its oligomers are replaced with acrylic acid or methyl group. The product obtained by the esterification of acrylic acid; the product obtained by the esterification of the two terminal hydroxyl groups of propylene glycol or its oligomers with acrylic acid or methacrylic acid; neopentyl glycol di(meth)acrylate, hexanediol di (Meth)acrylates and butanediol di(meth)acrylates, etc., the hydroxyl groups of dihydric alcohols are esterified with acrylic acid or methacrylic acid; bisphenol A, bisphenol A alkylene oxide The two terminal hydroxyl groups of adducts or these halogen-substituted products are esterified with acrylic acid or methacrylic acid; polyols such as trimethylolpropane and neotaerythritol are esterified with acrylic acid or methacrylic acid The products obtained by adding the epoxy group of glycidyl acrylate or glycidyl methacrylate to these terminal hydroxyl groups by ring-opening; the epoxy group of glycidyl acrylate or glycidyl methacrylate Products obtained by ring-opening addition of radicals to succinic acid, adipic acid, terephthalic acid, phthalic acid, dibasic acids such as these halogen substitution products, and these alkylene oxide adducts, etc.; (methyl) Aromatic divinyl compounds such as divinyl benzene and aryl acrylates. Among these, ethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, and neopentyl glycol dimethacrylate are preferably used.

The (meth)acrylic resin may be modified by further reacting with the functional groups possessed by the copolymer. Examples of the reactant include intramolecular demethanol condensation reaction of methyl acrylate group of methyl acrylate and hydroxyl group of methyl 2-(hydroxymethyl)acrylate, carboxyl group of acrylic acid and 2-(hydroxymethyl)acrylic acid. The dehydration condensation reaction of the hydroxyl group of methyl ester in the polymer chain, etc.

The glass transition temperature Tg of the (meth)acrylic resin is preferably in the range of 80 to 120°C. In order to adjust the Tg of the (meth)acrylic resin to the above range, the polymerization ratio of the methacrylate-based monomer and the acrylate-based monomer, the carbon chain length of each ester group, or the The kind of functional group it has, or the method of the polymerization ratio of the polyfunctional monomer to the whole monomer, etc.

(meth)acrylic-type resin may contain well-known additives as needed. Examples of known additives include lubricants, anti-caking agents, thermal stabilizers, antioxidants, antistatic agents, light fastness agents, impact resistance improvers, surfactants, and the like.

The (meth)acrylic resin may contain acrylic rubber particles which are impact modifiers from the viewpoints of the film formability of the film, the shock resistance of the film, and the like. The acrylic rubber particles referred to here refer to particles having an elastic polymer mainly composed of acrylate as an essential component, and examples include those having substantially only a single-layer structure composed of the elastic polymer, or elastic polymerization of the same. The object is a multi-layer structure of one layer. An example of such an elastic polymer includes a cross-linked elastic copolymer obtained by copolymerizing an alkyl acrylate as a main component with other vinyl-based monomers and cross-linkable monomers which can be copolymerized therewith. As the alkyl acrylate that is the main component of the elastic polymer, for example, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, etc., with alkyl groups having an alkyl group of about 1 to 8 carbon atoms, can be mentioned. Specifically, it is preferable to use an acrylate having an alkyl group having 4 or more carbon atoms. Other vinyl-based monomers that can be copolymerized with this alkyl acrylate include compounds having one polymerizable carbon-carbon double bond in the molecule, and more specifically, methyl methacrylate, etc. Methacrylates, aromatic vinyl compounds such as styrene, vinyl cyanide compounds such as acrylonitrile, and the like. In addition, as a crosslinkable monomer, a crosslinkable compound having at least two polymerizable carbon-carbon double bonds in the molecule can be mentioned, and more specifically, ethylene glycol di(meth)acrylate can be mentioned. and (meth)acrylates of polyols such as butanediol di(meth)acrylate, vinyl esters of (meth)acrylic acid such as allyl (meth)acrylate, divinylbenzene, and the like.

In addition, a laminate of a film composed of a (meth)acrylic resin containing no rubber particles and a film composed of a (meth)acrylic resin containing rubber particles may be used as the first thermoplastic resin film 21 and/or or the second thermoplastic resin film 22 .

The cellulose ester-based resin is a resin in which at least a part of the hydroxyl groups in cellulose is acetate-esterified, and may be a mixed ester in which a part is acetate-esterified and a part is other-esterified. The cellulose ester-based resin is preferably an acetyl cellulose-based resin. Specific examples of the acetyl cellulose-based resin include triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, cellulose acetate butyrate, and the like.

The first thermoplastic resin film 21 and/or the second thermoplastic resin film 22 may be a protective film for protecting the polarizing film 10, or may be a film having optical functions, such as a retardation film. The first thermoplastic resin film 21 and/or the second thermoplastic resin film 22 may be an unstretched film or a uniaxially or biaxially stretched film. For example, by stretching a thermoplastic resin film made of the above-mentioned materials (uniaxial stretching or biaxial stretching, etc.), or by forming a liquid crystal layer on the film, a film with an arbitrary retardation value can be produced. retardation film. The first thermoplastic resin film 21 and/or the second thermoplastic resin film 22 may have a surface treatment layer (coating layer) on the surface opposite to the polarizing film 10 . Specific examples of the surface treatment layer include an antiglare layer, a hard coat layer, an antireflection layer, a light diffusion layer, an antifouling layer, and an antistatic layer.

The thermoplastic resin constituting the first thermoplastic resin film 21 and the thermoplastic resin constituting the second thermoplastic resin film 22 may be the same or different. In terms of the embodiment of the polarizing plate including the first thermoplastic resin film 21, the first adhesive layer 15, the polarizing film 10, the second adhesive layer 25 and the second thermoplastic resin film 22 in this order, the following can be mentioned: 1) A polarizing plate, wherein the thermoplastic resin constituting the first thermoplastic resin film 21 is the same as the thermoplastic resin constituting the second thermoplastic resin film 22, and the thermoplastic resin is selected from polyester-based resins, polycarbonate-based resins, and polyolefin-based resins , a group consisting of (meth)acrylic resin and cellulose ester resin; 2) a polarizing plate, wherein the first thermoplastic resin film 21 is composed of (meth)acrylic resin, and the second thermoplastic resin The film 22 is made of polyolefin-based resin or cellulose ester-based resin. A suitable example of the embodiment of 1) is a polarizing plate in which both the first thermoplastic resin film 21 and the second thermoplastic resin film 22 are made of (meth)acrylic resin.

The first thermoplastic resin film 21 and/or the second thermoplastic resin film 22 may contain an ultraviolet absorber. Examples of the ultraviolet absorber include salicylate-based compounds, benzophenone-based compounds, benzotriazole-based compounds, cyanoacrylate-based compounds, nickel zirconium salt-based compounds, and the like.

The thickness of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 is, for example, 5 to 200 μm. From the viewpoint of increasing the rigidity R _1t and R _2t of these thermoplastic resin films, the thickness of these thermoplastic resin films is preferably 20 μm or more, more preferably 40 μm or more, and even more preferably 60 μm or more. The thickness of these thermoplastic resin films is preferably 160 μm or less, more preferably 140 μm or less, and even more preferably 120 μm or less, from the viewpoint of thinning the polarizing plate and the like. The thickness of the first thermoplastic resin film 21 and the thickness of the second thermoplastic resin film 22 may be the same or different.

The tensile modulus of elasticity of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 at 80°C is preferably 500 MPa or more, more preferably 700 MPa or more, from the viewpoint of increasing the rigidity R _1t and R _2t of the film. The tensile modulus of elasticity is usually 7000 MPa or less. The tensile modulus of elasticity at 80° C. of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 may be the same or different from each other.

From the viewpoint of increasing the rigidity product represented by the above formula (I) and even the rigidity product represented by the above formula (II), the rigidity R _1t of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 , R _2t is preferably 900 MPa·mm ³ or more. From the viewpoint of thinning the polarizing plate, etc., the rigidity R _p is preferably 4000 MPa·mm ³ or less, and more preferably 5000 MPa·mm ³ or less. Rigidities R _1t and R _2t of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 may be the same or different from each other.

(5) Adhesive layer

The first adhesive layer 15 and the second adhesive layer 25 may be formed of an active energy ray-curable adhesive, a thermosetting adhesive, or a water-based adhesive, and from the viewpoint of improving the rigidity R _1a and R _2a of the adhesive layers It is preferable that at least one of them is formed of an active energy ray-curable adhesive, and it is more preferable that both the adhesive layers are formed of an active energy ray-curable adhesive. In this case, the first adhesive layer 15 and the second adhesive layer 25 are cured product layers of an active energy ray-curable adhesive. The first adhesive layer 15 and the second adhesive layer 25 may be formed of the same type of adhesive, or may be formed of different types of adhesives. Active energy ray-curable adhesives are adhesives that are cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron rays, and X-rays. The active energy ray-curable adhesive is preferably an ultraviolet-curable adhesive. The adhesive is responsible for bonding the first thermoplastic resin film 21 to the polarizing film 10 and bonding the second thermoplastic resin film 22 to the polarizing film 10 .

From the viewpoint of improving the rigidity R _1a and R _2a of the adhesive layer, the active energy ray-curable adhesive preferably contains one or more cation-curable components (A). The cation-curable component (A) is a component that can be cured by cationic polymerization caused by irradiation with active energy rays. Adhesion is expressed by the polymerization hardening of the cationic curable component (A).

(5-1) Cation sclerosing component (A)

As a cationic curable component (A), an epoxy compound (A1) is mentioned. The epoxy compound means a compound having one or two or more epoxy groups in the molecule. The cationic curable component (A) may contain one or two or more types of epoxy compounds (A1).

As the epoxy compound (A1), aromatic epoxy compound (A1-1), aliphatic diglycidyl compound (A1-2), epoxy group-containing polymer (A1-3), monofunctional Aliphatic epoxy compound (A1-4) etc. The epoxy compound (A1) may comprise selected from aromatic epoxy compound (A1-1), aliphatic diglycidyl compound (A1-2), epoxy group-containing polymer (A1-3) and monofunctional aliphatic Two or more epoxy compounds of the group consisting of the epoxy compound (A1-4).

In addition, the compounds in which X and/or Y in the examples of the epoxy group-containing polymer (A1-3) described later have “aromatic rings and epoxy groups” are not included in the aromatic epoxy compound (A1) -1). Likewise, the compound in which X and/or Y in the epoxy group-containing polymer (A1-3) described later has an "epoxy group" is not included in the monofunctional aliphatic epoxy compound (A1-4) )middle.

The above-mentioned aromatic epoxy compound (A1-1) is an epoxy compound having an aromatic ring. The epoxy compound (A1) may contain one kind or two or more kinds of the aromatic epoxy compound (A1-1). Specific examples of the aromatic epoxy compound (A1-1) include monohydric phenols such as phenol, cresol, and butylphenol, bisphenol derivatives such as bisphenol A and bisphenol F, and alkylene oxide adducts thereof. Mono- or polyglycidyl ether compounds; epoxy novolac resins (novolak-type epoxy resins); mono- or poly-aromatic compounds with 2 or more phenolic hydroxyl groups such as resorcinol, hydroquinone, catechol, etc. Glycidyl ethers; glycidyl ethers of aromatic compounds having two or more alcoholic hydroxyl groups, such as benzenedimethanol, benzenediethanol, and benzenedibutanol; phthalic acid, terephthalic acid, trimellitic acid, etc., having two Glycidyl ester of polybasic acid aromatic compounds of the above carboxyl groups; glycidyl ester of benzoic acid, or glycidyl ester of toluic acid, naphthoic acid, etc.; styrene oxide, alkylated styrene oxide , styrene oxides such as epoxides of vinylnaphthalene, or diepoxides of divinylbenzene, etc.

Among these, from the viewpoint of curability and adhesiveness, the aromatic epoxy compound (A1-1) preferably contains a polyfunctional aromatic epoxy compound, and more preferably contains a tri- or more functional aromatic epoxy compound. Moreover, it is preferable that the epoxy equivalent of an aromatic epoxy compound (A1-1) is 80-500 from a sclerosing|hardenability and adhesive viewpoint.

The epoxy compound (A1) may contain one or more aliphatic diglycidyl compounds (A1-2). The inclusion of the aliphatic diglycidyl compound (A1-2) is advantageous from the viewpoint of lowering the viscosity of the active energy ray-curable adhesive. Moreover, it is also advantageous from the viewpoint of improving rigidity R _1a and R _2a of the adhesive layer that the aliphatic diglycidyl compound (A1-2) is contained. As the aliphatic diglycidyl compound (A1-2), it is more preferable to include the following formula (III):

the indicated compound. In the above formula (III), Z represents a straight-chain or branched alkylene group or a divalent alicyclic hydrocarbon group having 1 to 9 carbon atoms, and the methylene group in the alkylene group may be selected from oxygen atom, -CO Divalent group substitution of -O-, -O-CO-, -SO ₂ -, -SO- or -CO-. Typical examples of the divalent alicyclic hydrocarbon group include a cyclopentylene group and a cyclohexylene group.

In the above formula (III), the compound in which Z is an alkylene group is diglycidyl ether of alkanediol, and specific examples thereof include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, and 1,3-propylene glycol diglycidyl ether. Glyceryl ether, 1,4-butanediol diglycidyl ether, neopentyl glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, and the like. Among them, in the above formula (III), Z is an alkylene group from the viewpoint of lowering the viscosity of the active energy ray-curable adhesive and the viewpoint of improving the rigidity R _1a and R _2a of the adhesive layer. The compound is preferably a compound in which Z in the above formula (III) is a branched alkylene having 3 to 10 carbons, such as propylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, and the like.

The epoxy compound (A1) may contain one type or two or more types of epoxy group-containing polymers (A1-3). The inclusion of the epoxy group-containing polymer (A1-3) is advantageous in terms of improving adhesion to the substrate. The epoxy group-containing polymer (A1-3) is derived from the following formula (IV):

The represented monomer (IV) and the following formula (V):

The polymer which has the epoxy group contained in X and/or Y which consists of the structural unit of 1 or more types of monomers of the group which the monomer (V) represents. Specifically, 1) a homopolymer obtained by polymerizing one kind of monomer (IV), 2) a copolymer obtained by polymerizing two or more kinds of monomers (IV), 3) one kind Homopolymers obtained by polymerizing monomer (V), 4) Copolymers obtained by polymerizing two or more monomers (V), 5) One or more monomers (IV) and one or more monomers (V) A copolymer obtained by polymerization, and 6) A mixture of two or more kinds of these polymers.

In the polymers of 1) and 2), X in one or more of the monomers (IV) contains an epoxy group. In the polymers of 3) and 4), Y of one or more monomers (V) contains an epoxy group. In the polymer of 5), X of monomer (IV) and/or Y of monomer (V) contains an epoxy group.

X in the above formula (IV) represents a hydrogen atom or an alkane having 1 to 7 carbon atoms which may be partially substituted by one or more functional groups selected from the group consisting of epoxy, oxetanyl, hydroxyl and carboxyl groups group, an alkoxy group having 1 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, or an alicyclic hydrocarbon group having 6 to 10 carbon atoms.

Examples of the alkyl group having 1 to 7 carbon atoms include methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, isobutyl, n-pentyl, isobutyl pentyl, tert-pentyl, n-hexyl, 2-hexyl, 3-hexyl, cyclohexyl, 4-methylcyclohexyl, n-heptyl, 2-heptyl, 3-heptyl, isoheptyl, tert-heptyl Base et al. Among these, from the viewpoint of the rigidity of the adhesive layer, an alkyl group having 1 to 4 carbon atoms is preferable.

Examples of alkoxy groups having 1 to 7 carbon atoms include methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, 2nd butoxy, 3rd butoxy, isopropoxy Butoxy, n-pentyloxy, isopentyloxy, tert-pentyloxy, n-hexyloxy, 2-hexyloxy, 3-hexyloxy, cyclohexyloxy, 4-methylcyclohexyloxy, n-heptyloxy, 2-heptyloxy, 3-heptyloxy, isoheptyloxy, tertiary heptyloxy and the like. Among these, an alkoxy group having 1 to 4 carbon atoms is preferable from the viewpoint of the rigidity of the adhesive layer.

As the aryl group having 6 to 12 carbon atoms, a phenyl group, a methylphenyl group, a naphthyl group and the like can be mentioned. The number of carbon atoms is preferably 6 to 10.

As an aryloxy group having 6 to 12 carbon atoms, a phenoxy group, a methylphenoxy group, a naphthoxy group and the like can be mentioned. The number of carbon atoms is preferably 6 to 10.

Examples of the alicyclic hydrocarbon group having 6 to 10 carbon atoms include cyclohexyl, methylcyclohexyl, norbornyl, bicyclopentyl, bicyclooctyl, trimethylbicycloheptyl, tricyclooctyl, and tricyclodecyl base, spirooctyl, spirobicyclopentyl, adamantyl, isobornyl, etc.

In the above formula (IV), the following formulae (IVa), (IVb) and The monomer represented by (IVc).

(in the formula, R ⁴ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and m represents an integer of 1 to 6)

(in the formula, R ⁵ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and n represents an integer of 1 to 6)

(In the formula, R ⁶ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and s represents an integer of 1 to 6).

R ¹ in the above formula (V) represents a hydrogen atom, a methyl group or a halogen atom. Y represents an alkyl group having 1 to 7 carbon atoms, an aryl group having 6 to 12 carbon atoms that may be substituted with one or more functional groups selected from the group consisting of epoxy, oxetanyl, hydroxyl and carboxyl groups, or Alicyclic hydrocarbon group having 6 to 10 carbon atoms.

As said halogen atom, fluorine, chlorine, bromine, iodine, etc. are mentioned. Specific examples of the alkyl group having 1 to 7 carbon atoms, the aryl group having 6 to 12 carbon atoms, and the alicyclic hydrocarbon group having 6 to 10 carbon atoms are the same as X in formula (IV).

In the above formula (V), the following formulae (Va), (Vb) and The monomer represented by (Vc).

(In the formula, R ¹ is the same as the above formula (V), R ⁷ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and t represents an integer of 1 to 6)

(In the formula, R ¹ is the same as the above formula (V), R ⁸ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and p represents an integer of 1 to 6)

(In the formula, R ¹ is the same as the above formula (V), R ⁹ represents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and q represents an integer of 1 to 6).

The epoxy group-containing polymer (A1 -3) The weight average molecular weight of standard polystyrene conversion by gel permeation chromatography (GPC) is preferably 5,000 to 500,000, more preferably 6,000 to 100,000.

The epoxy compound (A1) may contain one type or two or more types of the monofunctional aliphatic epoxy compound (A1-4). Examples of the monofunctional aliphatic epoxy compound (A1-4) include glycidyl ether products of aliphatic alcohols, glycidyl esters of alkyl carboxylic acids, and the like, and specific examples thereof include allyl glycidyl ether, butyl glycidyl ether, and the like. Glycidyl ether, 2-butylphenyl glycidyl ether, 2-ethylhexyl glycidyl ether, mixed alkyl glycidyl ether with 12 and 13 carbon atoms, glycidyl ether of alcohol, monoglycidyl ether of aliphatic higher alcohol, Glycidyl esters of higher fatty acids, etc.

The epoxy compound (A1) may contain a cationic curable epoxy compound not belonging to any one of the above (A1-1) to (A1-4).

Among these, it is preferable that the epoxy compound (A1) contains an aliphatic diglycidyl compound (A1-2) and/or an epoxy compound from the viewpoint of improving the rigidity R _1a and R _2a of the adhesive layer. base polymer (A1-3), and preferably an aliphatic diglycidyl compound (A1-2) and an epoxy group-containing polymer (A1-3). The total content of the aliphatic diglycidyl compound (A1-2) and the epoxy group-containing polymer (A1-3) in the epoxy compound (A1) is less than 100 parts by weight of the epoxy compound (A1). It is preferably 40 to 100 parts by weight, more preferably 50 to 100 parts by weight, still more preferably 60 to 100 parts by weight.

The cation-curable component (A) may contain one or more cation-curable components other than the epoxy compound (A1). Examples of other cationic curable components include oxetane compounds (A2), vinyl ether compounds (A3), cyclic lactone compounds (A4), cyclic acetal compounds (A5), and cyclic sulfides Compound (A6), spiro orthoester compound (A7) and the like. In addition, the compound in which X and/or Y in the example of the above-mentioned epoxy group-containing polymer (A1-3) has "oxetanyl group" is not included in the oxetane compound (A2) here middle.

The cationic curable component (A) may contain one or more oxetane compounds (A2). The oxetane compound (A2) is a compound having an oxetanyl group, and specific examples thereof include 3,7-bis(3-oxetanyl)-5-oxa-nonane, 1,4- Bis[(3-ethyl-3-oxetanylmethoxy)methyl]benzene, 1,2-bis[(3-ethyl-3-oxetanylmethoxy)methyl]ethane, 1 ,3-bis[(3-ethyl-3-oxetanylmethoxy)methyl]propane, ethylene glycol bis(3-ethyl-3-oxetanylmethyl) ether, triethylene glycol bis (3-ethyl-3-oxetanylmethyl)ether, tetraethylene glycol bis(3-ethyl-3-oxetanylmethyl)ether, 1,4-bis(3-ethyl-3- Oxetanylmethoxy)butane, 1,6-bis(3-ethyl-3-oxetanylmethoxy)hexane, 3-ethyl-3-[(phenoxy)methyl]oxy Hetetane, 3-ethyl-3-(hexyloxymethyl)oxetane, 3-ethyl-3-(2-ethylhexyloxymethyl)oxetane, 3 -Ethyl-3-(hydroxymethyl)oxetane, 3-ethyl-3-(chloromethyl)oxetane, etc.

Examples of the vinyl ether compound (A3) include aliphatic or alicyclic vinyl ether compounds, and specific examples thereof include n-amyl vinyl ether, isopentyl vinyl ether, n-hexyl vinyl ether, and n-octyl vinyl ether. Vinyl ethers of alkyl or alkenyl alcohols with 5 to 20 carbon atoms, such as vinyl ether, 2-ethylhexyl vinyl ether, n-dodecyl vinyl ether, stearyl vinyl ether, oleyl vinyl ether, etc. 2-hydroxyethyl vinyl ether, 3-hydroxypropyl vinyl ether, 4-hydroxybutyl vinyl ether and other vinyl ethers containing hydroxyl groups; cyclohexyl vinyl ether, 2-methylcyclohexyl vinyl ether Ethyl ether, cyclohexyl methyl vinyl ether, benzyl vinyl ether and other vinyl ethers of monoalcohols with aliphatic or aromatic rings; glycerol monovinyl ether, 1,4-butanediol divinyl ether ether, 1,6-hexanediol divinyl ether, neopentyl glycol divinyl ether, neopentaerythritol divinyl ether, neotaerythritol tetravinyl ether, trimethylolpropane divinyl ether , Trimethylolpropane trivinyl ether, 1,4-dihydroxycyclohexane monovinyl ether, 1,4-dihydroxycyclohexane divinyl ether, 1,4-dihydroxymethylcyclohexane Mono- or polyvinyl ethers of polyols such as monovinyl ether and 1,4-dihydroxymethylcyclohexane divinyl ether; diethylene glycol divinyl ether, triethylene glycol divinyl ether, Diethylene glycol monobutyl monovinyl ether and other polyalkanediol mono or divinyl ethers; glycidyl vinyl ether, ethylene glycol vinyl ether methacrylate and other vinyl ethers.

The cationic curable component (A) preferably contains other cationic curable components other than the epoxy compound (A1), and among these, it is more preferable to increase the rigidity R _1a and R _2a of the adhesive layer. The epoxy compound (A1) and the oxetane compound (A2) are included. The content of other cationic curable components (preferably including the oxetane compound (A2)) in the cationic curable component (A) is 100 weight in the total amount of the epoxy compound (A1) and other cationic curable components 5 parts by weight or more, more preferably 10 parts by weight or more, even more preferably 20 parts by weight or more, particularly preferably 30 parts by weight or more ( For example, 40 parts by weight or more). The content of other cationic curable components is usually 90 parts by weight or less in 100 parts by weight of the total amount of epoxy compound (A1) and other cationic curable components, that is, in 100 parts by weight of cationic curable components (A) , from the viewpoint of accelerating curing immediately after UV irradiation, is preferably 80 parts by weight or less, more preferably 70 parts by weight or less, still more preferably 60 parts by weight or less. In a preferred embodiment, the cationic curable component (A) contains 40 to 70% by weight (preferably 45 to 65% by weight) of the epoxy compound (A1) and 30 to 60% by weight (preferably 35 to 55% by weight) of the oxetane compound (A2).

The epoxy compound (A1) tends to have a relatively rapid onset of hardening compared to the oxetane compound (A2), on the other hand, the oxetane compound (A1) After the hardening of the cyclobutane compound (A2) starts, the hardening proceeds relatively rapidly, and thus by rapidly starting the hardening and then also rapidly hardening, as a result, a hardened layer having a sufficient storage elastic modulus can be formed. In other words, the usage-amount of the epoxy compound (A1) and the oxetane compound (A2) is preferably within the above-mentioned range.

(5-2) Cationic polymerization initiator (B)

The active energy ray-curable adhesive containing the cation-curable component (A) usually contains a cationic polymerization initiator (B). Thereby, the cationic curable component (A) can be hardened by cationic polymerization by irradiation of active energy rays, and an adhesive layer can be formed. The cationic polymerization initiator (B) generates cationic species or Lewis acid by irradiation with active energy rays such as visible rays, ultraviolet rays, X-rays, and electron rays, and starts the polymerization reaction of the cationic curable component (A). substance. Since the cationic polymerization initiator (B) acts photocatalytically, even if it is mixed with the cationic curable component (A), it is excellent in storage stability and workability. As a compound that can be used as a cationic polymerization initiator (B) to generate a cationic species or a Lewis acid by irradiation with active energy rays, for example, aromatic diazonium salts; such as aromatic iodonium salts or aromatic pericynium salts can be exemplified. Onium salts such as salts; iron-aromatic complexes, etc.

As the aromatic diazonium salt, for example, benzene diazonium hexafluoroantimonate, benzene diazonium hexafluorophosphate, and benzene diazonium hexafluoroborate can be mentioned.

Examples of the aromatic iodonium salt include diphenyl iodonium (pentafluorophenyl) borate, diphenyl iodonium hexafluorophosphate, diphenyl iodonium hexafluoroantimonate, bis(4-nonyl) phenyl) iodonium hexafluorophosphate.

As the aromatic perylene salt, for example, triphenyl perylene hexafluorophosphate, triphenyl perylene hexafluoroantimonate, triphenyl perylene (pentafluorophenyl) borate, 4,4'-bis [Diphenylperyl]diphenylsulfide bishexafluorophosphate, 4,4'-bis[bis(β-hydroxyethoxy)phenylperyl]diphenylsulfide bishexafluoroantimonate , 4,4'-bis[bis(β-hydroxyethoxy)phenyl peryl]diphenyl sulfide bishexafluorophosphate, 7-[bis(p-tolyloxy) peryl]-2- Isopropylthioxanthone hexafluoroantimonate, 7-[bis(p-toluyl) peryl]-2-isopropylthioxanthone tetra(pentafluorophenyl)borate, 4-benzene ylcarbonyl-4'-diphenylperylanyl-diphenylsulfide hexafluorophosphate, 4-(p-tert-butylphenylcarbonyl)-4'-diphenylperylanyl-diphenylsulfide hexa Fluoroantimonate, 4-(p-tert-butylphenylcarbonyl)-4'-bis(p-toluyl) peryl-diphenylsulfide tetra(pentafluorophenyl)borate.

Examples of iron-aromatic complexes include xylene-cyclopentadienyl iron (II) hexafluoroantimonate, cumene-cyclopentadienyl iron (II) hexafluorophosphate, Toluene-cyclopentadienyl iron(II) gins(trifluoromethylsulfonyl)methanate.

The active energy ray-curable adhesive may contain one or more cationic polymerization initiators (B). Among the above, especially aromatic periconium salts are preferable because they have ultraviolet absorption properties even in the wavelength region around 300 nm, are excellent in curability, and can provide an adhesive layer having high rigidity and good adhesive strength.

The content of the cationic polymerization initiator (B) is usually 0.1 to 10 parts by weight, preferably 0.5 to 8 parts by weight, more preferably 1 to 6 parts by weight relative to 100 parts by weight of the cationic curable component (A) . By containing 0.1 part by weight or more of the cationic polymerization initiator (B), the cationic curable component (A) can be sufficiently cured. Thereby, the rigidity of an adhesive bond layer can be improved. On the other hand, if the amount is too large, the ionic substances in the cured product will increase, the hygroscopicity of the cured product will increase, and the durability of the polarizing plate may be lowered. A) The amount of the cationic polymerization initiator (B) is usually 10 parts by weight or less for 100 parts by weight.

(5-3) Sensitizer (C)

The active energy ray curable adhesive may contain a sensitizer (C). The cationic polymerization initiator (B) exhibits maximum absorption in a wavelength region near 300 nm or less, for example, and generates cationic species or Lewis acid by sensing light of a wavelength near the cationic species and causes the cationic cation of the cationic hardening component (A). The polymerization starts to proceed, but in order to also sense light of wavelengths longer than these, the sensitizer (C) is preferably one that exhibits an absorption maximum in the wavelength region longer than 380 nm. As such a photosensitizer (C), an anthracene-based compound is preferably used.

Specific examples of anthracene-based compounds include, for example, 9,10-dimethoxyanthracene, 9,10-diethoxyanthracene, 9,10-dipropoxyanthracene, and 9,10-diisopropoxyanthracene Anthracene, 9,10-dibutoxyanthracene, 9,10-dipentyloxyanthracene, 9,10-dihexoxyanthracene, 9,10-bis(2-methoxyethoxy)anthracene, 9 , 10-bis(2-ethoxyethoxy)anthracene, 9,10-bis(2-butoxyethoxy)anthracene, 9,10-bis(3-butoxypropoxy)anthracene, 2-Methyl or 2-ethyl-9,10-dimethoxyanthracene, 2-methyl or 2-ethyl-9,10-diethoxyanthracene, 2-methyl or 2-ethyl- 9,10-Dipropoxyanthracene, 2-methyl or 2-ethyl-9,10-diisopropoxyanthracene, 2-methyl or 2-ethyl-9,10-dibutoxyanthracene , 2-methyl or 2-ethyl-9,10-dipentyloxyanthracene, 2-methyl or 2-ethyl-9,10-dihexyloxyanthracene.

By including the sensitizer (C) in the active energy ray-curable adhesive, the curability of the adhesive can be improved compared to the case where the sensitizer (C) is not included. Such an effect can be exhibited by making content of a sensitizer (C) 0.1 weight part or more with respect to 100 weight part of cationic curable components (A). On the other hand, when the content of the sensitizer (C) is too large, problems such as precipitation may occur during low-temperature storage, so the amount thereof is preferably 2 with respect to 100 parts by weight of the cationic curable component (A). parts by weight or less. In addition, from the viewpoint of maintaining the neutral gradation of the polarizing plate, it is more advantageous to reduce the content of the photosensitizer. The amount of (C) is set to be in the range of 0.1 to 0.5 parts by weight, more preferably 0.1 to 0.3 parts by weight.

Depending on the composition of the active energy ray-curable adhesive to be used, it may be advantageous not to include the sensitizer (C). For example, when the active energy ray-curable adhesive contains the cationic curable component (A), and the cationic curable component (A) contains 40 to 70 wt % (preferably, when the total amount of the cation curable component (A) is set to 100 wt %) 45 to 65 wt %) of epoxy compound (A1) and 30 to 60 wt % (preferably 35 to 55 wt %) of oxetane compound (A2), even if active energy ray hardening The adhesive agent does not substantially contain the sensitizer (C), and also exhibits good curability. To be substantially free means that the content of the sensitizer (C) is 0 to 0.01 part by weight with respect to 100 parts by weight of the cationic curable component (A). By not containing substantially the sensitizer (C), the coloring of the polarizing plate can be suppressed, whereby the neutral gradation of the polarizing plate can be well maintained.

(5-4) Sensitizer (D)

The active energy ray curable adhesive may contain a sensitizer (D). The sensitizer (D) is preferably a naphthalene-based photosensitizer.

Specific examples of naphthalene-based photosensitizers include, for example, 4-methoxy-1-naphthol, 4-ethoxy-1-naphthol, 4-propoxy-1-naphthol, 4- Butoxy-1-naphthol, 4-hexyloxy-1-naphthol, 1,4-dimethoxynaphthalene, 1-ethoxy-4-methoxynaphthalene, 1,4-diethoxy naphthalene, 1,4-dipropoxynaphthalene, 1,4-dibutoxynaphthalene.

By including a sensitizing aid (D) such as a naphthalene-based photosensitizing aid in the active energy ray-curable adhesive, the curability of the adhesive can be improved compared to the case where it is not included. Such an effect can be exhibited by making content of a sensitization adjuvant (D) 0.1 weight part or more with respect to 100 weight part of cationic curable components (A). On the other hand, when the content of the sensitizer (D) is too large, problems such as precipitation may occur during storage at low temperature, so the amount is preferably set to 100 parts by weight of the cationic curable component (A). 5 parts by weight or less, more preferably 3 parts by weight or less.

(5-5) Other ingredients

The active energy ray curable adhesive may contain other components than the above. Examples of other components include thermal cationic polymerization initiators, polyols, ion trapping agents, antioxidants, photostabilizers, chain transfer agents, adhesion imparting agents, thermoplastic resins, fillers, flow modifiers, plasticizers agent, defoamer, leveling agent, pigment, organic solvent, etc.

(5-6) Thickness, storage elastic modulus and rigidity of adhesive layer

The thickness after hardening of the 1st adhesive agent layer 15 and the 2nd adhesive agent layer 25 is 0.01-20 micrometers, for example. From the viewpoint of increasing the rigidity R _1a and R _2a of these adhesive layers, the thickness of these adhesive layers is preferably 0.1 μm or more, more preferably 0.5 μm or more, and even more preferably 1 μm or more. The thickness of these adhesive layers is preferably 15 μm or less, and more preferably 10 μm or less, from the viewpoint of thinning the polarizing plate and the like. The thickness of the first adhesive layer 15 and the thickness of the second adhesive layer 25 may be the same or different. When the thickness of an adhesive agent layer is made too small, it becomes easy to generate|occur|produce a bubble mixing into an adhesive agent layer, and adhesiveness and durability fall.

From the viewpoint of increasing the rigidity R _1a and R _2a of the adhesive layer, the storage elastic modulus of the first adhesive layer 15 and the second adhesive layer 25 at 80° C. is preferably 100 MPa or more, more preferably 200 MPa or more , more preferably 400MPa or more, particularly preferably 500MPa or more. The tensile modulus of elasticity is usually 3000 MPa or less. The storage elastic moduli at 80° C. of the first adhesive layer 15 and the second adhesive layer 25 may be the same or different from each other.

From the viewpoint of increasing the rigidity product represented by the above formula (I) and even the rigidity product represented by the above formula (II), the rigidity R 1a of the first adhesive layer 15 and the second adhesive layer 25 , R _1a , R _2a is preferably 1×10 ^-8 MPa·mm ³ or more, more preferably 5×10 ^-7 MPa·mm ³ or more. From the viewpoint of thinning of the polarizing plate, etc., the rigidity R _p is preferably 5×10 ^-3 MPa·mm ³ or less, and more preferably 3×10 ^-4 MPa·mm ³ or less. Rigidities R _1a and R _2a of the first adhesive layer 15 and the second adhesive layer 25 may be the same or different from each other.

(6) Manufacture of polarizing plate

The polarizing plate shown in FIG. 1 can be obtained by adhering the first thermoplastic resin film 21 to one side of the polarizing film 10 using the above-mentioned adhesive (preferably an active energy ray-curable adhesive). The polarizing plate shown in FIG. 2 can be obtained by bonding the first thermoplastic resin film 21 to one side of the polarizing film 10 and bonding the second thermoplastic resin film 22 to the other side using the above-mentioned adhesive.

For example, the polarizing plate shown in FIG. 1 can be manufactured by the following steps: forming a coating layer of adhesive on the bonding surface of the polarizing film 10 and/or the first thermoplastic resin film 21, After the polarizing film 10 and the first thermoplastic resin film 21 are bonded together, if the adhesive is an active energy ray-curable adhesive, the coating layer of the uncured adhesive is cured by irradiation with active energy rays. The same applies to the polarizing plate shown in Figure 2. When forming the coating layer of the adhesive, various coating methods such as a doctor blade, a wire bar, a die coater, a notch coater, and a gravure coater can be used. In addition, while continuously supplying the polarizing film 10 and the first thermoplastic resin film 21 so that the adhesive surfaces of both are inside, a method of casting an adhesive therebetween may be employed. When manufacturing a polarizing plate including the first and second thermoplastic resin films 21 and 22, the bonding of the first thermoplastic resin film 21 and the second thermoplastic resin film 22 to the polarizing film 10 may be performed simultaneously or sequentially.

Before the polarizing film 10 and the first and/or second thermoplastic resin films 21 and 22 are bonded, saponification treatment and corona treatment may be applied to the bonding surface of the thermoplastic resin film and/or the bonding surface of the polarizing film 10 , Plasma treatment, primer treatment, anchor coating treatment, flame treatment, etc.

The light source for irradiating the active energy rays may be any one that can generate ultraviolet rays, electron rays, X rays, or the like. Specifically, a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultra-high-pressure mercury lamp, a fluorescent lamp for insect traps, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, etc., which have a light emission distribution at a wavelength of 400 nm or less, are preferably used.

The active energy ray irradiation intensity is not particularly limited, but the irradiation intensity in a wavelength region effective for activation of the cationic polymerization initiator (B) is preferably 0.1 to 3000 mW/cm ² . If it is less than 0.1 mW/cm ² , the reaction time will be too long. If it exceeds 3000 mW/cm ² , the yellowing of the adhesive or the polarizing film will occur due to the heat radiated from the lamp and the heat release during the polymerization of the adhesive. the possibility of deterioration.

The irradiation time of the active energy ray is also not particularly limited, but is preferably set so that the cumulative light amount represented by the product of the irradiation intensity and the irradiation time is 10 to 5000 mJ/cm ² . If it is less than 10 mJ/cm ² , the generation of active species derived from the cationic polymerization initiator (B) is insufficient, and there is a possibility that the curing of the obtained adhesive layer may become insufficient. On the other hand, When the said accumulated light quantity exceeds 5000mJ/cm< ² >, the irradiation time will become very long, and it will become unfavorable for improvement of productivity.

The polarizing plate obtained in the above manner, in the case of the polarizing plate composed of the first thermoplastic resin film 21, the first adhesive layer 15 and the polarizing film 10 shown in FIG. From the viewpoint of cracking and meeting the requirement of thinning the polarizing plate, it is preferably 10 to 200 μm, more preferably 25 to 130 μm, and even more preferably 25 to 110 μm thick. Regardless of whether the polarizing plate includes the first thermoplastic resin film 21 , the first adhesive layer 15 and other layers other than the polarizing film 10 , the thickness referred to here refers to the first thermoplastic resin film 21 , the first adhesive layer 15 and the polarizing film 10 . Total thickness of film 10 . In the case of the polarizing plate composed of the first thermoplastic resin film 21, the first adhesive layer 15, the polarizing film 10, the second adhesive layer 25, and the second thermoplastic resin film 22 shown in FIG. From the viewpoint of cracking of the film 10 and the viewpoint of meeting the requirements of thinning the polarizing plate, the polarizing plate preferably has a thickness of 15 to 400 μm, more preferably has a thickness of 40 to 200 μm, and even more preferably has a thickness of 40 to 180 μm The thickness of the particularly preferred series has a thickness of 40 to 150 μm. Regardless of whether the polarizing plate includes layers other than the first thermoplastic resin film 21 , the first adhesive layer 15 , the polarizing film 10 , the second adhesive layer 25 and the second thermoplastic resin film 22 , the thickness here refers to the first 1 The total thickness of the thermoplastic resin film 21 , the first adhesive layer 15 , the polarizing film 10 , the second adhesive layer 25 , and the second thermoplastic resin film 22 .

The polarizing plate is generally laminated on the panel through an adhesive layer. When the polarizing plate is a polarizing plate composed of the first thermoplastic resin film 21 , the first adhesive layer 15 , the polarizing film 10 , the second adhesive layer 25 , and the second thermoplastic resin film 22 , the polarizing plate can be attached through the adhesive layer. The first thermoplastic resin film 21 and the panel are laminated, and the second thermoplastic resin film 22 and the panel may be laminated via an adhesive layer. For example, in the case where the second thermoplastic resin film 22 and the panel are laminated through the adhesive layer, the value of the product of the rigidity represented by the above formula (I) is preferably greater than the value of the rigidity represented by the above formula (II). value of the product.

[Example]

Hereinafter, although an Example and a comparative example are shown and this invention is demonstrated more concretely, this invention is not limited to these examples. Hereinafter, the parts and % indicating the usage amount or content are based on weight unless otherwise specified.

The thicknesses of the thermoplastic resin film, the polarizing film and the adhesive layer, the tensile elastic modulus of the thermoplastic resin film and the polarizing film, and the storage elastic modulus of the adhesive layer were measured according to the following methods.

(1) Thickness of thermoplastic resin film and polarizing film

A strip-shaped test piece having an MD length of 50 mm×TD length and a full width was cut out from the film. Next, the thickness of the film was measured at intervals of 100 mm in the film width direction using a digital micrometer "MH-15M" manufactured by Nikon Corporation. The average value of the obtained measurement value was made into thickness [mm].

(2) Tensile modulus of elasticity of thermoplastic resin film at 80°C

A rectangular test piece having an MD length of 100 mm and a TD length of 20 mm was cut out from the thermoplastic resin film. Next, the upper and lower jigs of the tensile testing machine ["Autograph AG-1S testing machine" manufactured by Shimadzu Corporation] were used to clamp both ends of the test piece in the MD longitudinal direction so that the interval between the jigs was 5 cm. In an environment of 80°C, the test piece was stretched in the MD longitudinal direction at a tensile speed of 5 mm/min. From the slope of the initial straight line in the obtained stress-strain curve, the tensile elastic modulus at 80°C was calculated. number [MPa].

(3) Tensile modulus of elasticity at 80°C in the direction of the penetration axis of the polarizing film

A rectangular test piece having an MD length (length in the transmission axis direction) of 100 mm×TD length (length in the absorption axis direction) of 20 mm was cut out from the polarizing film. Next, the MD longitudinal direction (penetration axis) of the above-mentioned test piece was clamped so that the interval between the clamps was 5 cm using the upper and lower clamps of a tensile testing machine ["Autograph AG-1S Tester" manufactured by Shimadzu Corporation]. direction) both ends, in the environment of 80 ° C, the test piece was stretched in the MD longitudinal direction (penetration axis direction) at a tensile speed of 5 mm/min, and the initial straight line in the obtained stress-strain curve was obtained. The slope of the polarizing film was calculated from the tensile modulus of elasticity [MPa] at 80°C in the direction of the transmission axis of the polarizing film.

(4) Storage elastic modulus of adhesive layer at 80°C

On one side of a cyclic polyolefin-based resin film with a thickness of 50 μm, a coating machine [Bar Coater manufactured by Daiichi Rika Co., Ltd.] was used, and the thickness after drying was obtained by Bar Coater #18. The adhesive composition was coated with a thickness of 25 μm. Then, using "D Bulb" manufactured by Fusion UV Systems, the cumulative light intensity of UVA in the UV wavelength region was 3000 mJ/cm ² (measured value using a measuring device: UV Power Puck II manufactured by Fusion UV) in The adhesive was cured by irradiating ultraviolet rays in the atmosphere with a temperature of 25°C and a relative humidity of 60%RH, and leaving it for 48 hours in the dark in an atmosphere with a temperature of 25°C and a relative humidity of 60%RH. This was cut into a size of 5 mm×30 mm, and the cyclic polyolefin-based resin film was peeled off to obtain a cured film of the adhesive. This cured film was held at a distance of 2 cm between the clamps using a dynamic viscoelasticity measuring device "DVA-220" manufactured by IT-Measuring Co., Ltd. so that its long side was in the stretching direction, and the frequency of stretching and shrinking was set. 1 Hz, and the heating rate was set to 3°C/min, and the storage elastic modulus at 80°C was obtained.

(Production Example 1: Preparation of Active Energy Ray Curable Adhesive)

After mixing the cationic curable component (A) and the cationic polymerization initiator (B) shown in Table 1, defoaming was performed to prepare an adhesive belonging to an active energy ray curable adhesive (ultraviolet curable adhesive). 1 and 2. The unit of the compounding quantity of each component in Table 1 is "part".

Details of each component shown in Table 1 are as follows.

[1] Epoxy compound A1-1: Special novolak type epoxy resin "157S20" manufactured by Mitsubishi Chemical Corporation, [2] Epoxy compound A1-2: Neopentyl glycol diglycidyl ether [in the above formula In (III), Z=-CH ₂ C(CH ₃ ) ₂ CH ₂ - compound], [3] Epoxy compound A1-3: composed of 25 parts of glycidyl methacrylate (GMA) and methacrylic acid Epoxy group-containing polymer (GMA-MMA copolymer) with a weight average molecular weight of 15,000 obtained by radical polymerization of a monomer composition consisting of 75 parts of methyl ester (MMA), [4] oxetane compound A2-1: Oxetane compound "OXT-221" (chemical name: 3-ethyl-3-[(3-ethyloxetan-3-yl)methan) manufactured by Toagosei Co., Ltd. Oxymethyl]oxetane), [5] cationic polymerization initiator (B): "CPI-110P" (chemical name: triaryl perylene hexafluorophosphate) manufactured by San Apro Co., Ltd., active ingredient : 100%).

(Production Example 2: Production of Polarizing Film 1 )

A polyvinyl alcohol film manufactured by Kuraray (“PE6000” manufactured by Kuraray Co., Ltd.) was continuously conveyed and immersed in a swelling bath composed of pure water at 20° C. for a residence time of 31 seconds (swelling step). Subsequently, the film pulled out from the swelling bath was immersed in a dyeing bath containing iodine at 30°C with a residence time of 122 seconds in a potassium iodide/water ratio of 2/100 (weight ratio) (dyeing step).

Then, the film pulled out from the dyeing bath was immersed in a cross-linking bath at 56°C having a potassium iodide/boric acid/water ratio of 12/4.1/100 (weight ratio) for a residence time of 70 seconds, followed by immersion for a residence time of 13 seconds In a crosslinking bath at 40°C with potassium iodide/boric acid/water 9/2.9/100 (weight ratio) (crosslinking step). In the dyeing step and the crosslinking step, longitudinal uniaxial stretching is performed by stretching between rolls in the bath. The total stretching ratio based on the original film was set to 5.5 times. Then, the film pulled out from the crosslinking bath was immersed in a cleaning bath composed of pure water at 5°C for a residence time of 3 seconds (cleaning step), and then introduced into a drying oven at 80°C for a residence time of 190 seconds During the drying process (drying step), the polarizing film 1 was obtained. The thickness of the polarizing film 1 was 25 μm.

(Production Example 3: Production of Polarizing Film 2 )

A polarizing film 2 was produced in the same manner as in Production Example 2, except that a polyvinyl alcohol film (“PE3000” produced by Kuraray Co., Ltd.) was used as a raw material film. The thickness of the polarizing film 2 was 12 μm.

<Example 1: Production of polarizing plate 1>

The first (meth)acrylic resin film ("Technolloy S001" manufactured by Sumitomo Chemical Co., Ltd., containing an ultraviolet absorber) and a cyclic polyolefin-based resin film (retardation film "ZEONOR" manufactured by Japan Zeon Corporation) were prepared. ”). On one side of each of these films, an adhesive 1 is applied using an adhesive coating apparatus to form an adhesive layer, and the first (meth)acrylic resin film is bonded to the polarizing film 1 via the adhesive layer. On one side, the cyclic polyolefin-based resin film was bonded to the other side. Next, ultraviolet rays were irradiated from the side of the cyclic polyolefin-based resin film so that the cumulative light intensity of UVA in the UV wavelength region was about 350 mJ/cm ² (measured value using a measuring device: UV Power Puck II manufactured by Fusion UV Co., Ltd.), and The adhesive layer was cured to obtain a polarizing plate 1 . The layer structure of the polarizing plate 1 is the first (meth)acrylic resin film (the first thermoplastic resin film) / the first adhesive layer composed of the adhesive 1 / the polarizing film 1 / the first adhesive layer composed of the adhesive 1. 2. Adhesive layer/cyclic polyolefin resin film (second thermoplastic resin film).

<Example 2: Production of polarizing plate 2>

A polarizing plate 2 was produced in the same manner as in Example 1, except that a second (meth)acrylic resin film (without an ultraviolet absorber) was used as the second thermoplastic resin film in place of the above-mentioned cyclic polyolefin resin film. Ultraviolet rays are irradiated from the side of the second (meth)acrylic resin film. The layer structure of the polarizing plate 2 is the first (meth)acrylic resin film (the first thermoplastic resin film) / the first adhesive layer composed of the adhesive 1 / the polarizing film 1 / the first adhesive layer composed of the adhesive 1. 2. Adhesive layer/2nd (meth)acrylic resin film (2nd thermoplastic resin film).

<Example 3: Production of polarizing plate 3>

In addition to using the above-mentioned cyclic polyolefin-based resin film instead of the first (meth)acrylic resin film as the first thermoplastic resin film, the second (meth)acrylic-based resin film was used instead of the above-mentioned cyclic polyolefin-based resin film as the first thermoplastic resin film. 2 The thermoplastic resin film and the polarizing plate 3 were produced in the same manner as in Example 1 except that the adhesive 2 was used when the second thermoplastic resin film and the polarizing film 1 were bonded together. Ultraviolet rays are irradiated from the cyclic polyolefin resin film side. The layer structure of the polarizing plate 3 is a cyclic polyolefin resin film (first thermoplastic resin film) / a first adhesive layer composed of adhesive 1 / polarizing film 1 / a second adhesive composed of adhesive 2 Layer/2nd (meth)acrylic resin film (2nd thermoplastic resin film).

<Comparative Example 1: Production of Polarizing Plate 4>

A polarizing plate 4 was produced in the same manner as in Example 2, except that the adhesive 2 was used as the adhesive for forming the first adhesive layer and the second adhesive layer. Ultraviolet rays are irradiated from the side of the second (meth)acrylic resin film. The layer structure of the polarizing plate 4 is the first (meth)acrylic resin film (the first thermoplastic resin film) / the first adhesive layer composed of the adhesive 2 / the polarizing film 1 / the first adhesive layer composed of the adhesive 2 . 2. Adhesive layer/2nd (meth)acrylic resin film (2nd thermoplastic resin film).

<Comparative Example 2: Production of Polarizing Plate 5>

Except using the third (meth)acrylic resin film (“Technolloy S001” manufactured by Sumitomo Chemical Co., Ltd., containing an ultraviolet absorber) instead of the first (meth)acrylic resin film as the first thermoplastic resin film, and using A polarizing plate 5 was produced in the same manner as in Example 2, except that the fourth (meth)acrylic resin film (excluding the ultraviolet absorber) was used as the second thermoplastic resin film instead of the second (meth)acrylic resin film. The ultraviolet ray is irradiated from the side of the fourth (meth)acrylic resin film. The layer structure of the polarizing plate 5 is the third (meth)acrylic resin film (the first thermoplastic resin film) / the first adhesive layer composed of the adhesive 1 / the polarizing film 1 / the first adhesive layer composed of the adhesive 1. 2. Adhesive layer/4th (meth)acrylic resin film (2nd thermoplastic resin film).

<Comparative Example 3: Production of Polarizing Plate 6>

A polarizing plate 6 was produced in the same manner as in Example 2 except that the polarizing film 2 was used instead of the polarizing film 1 . Ultraviolet rays are irradiated from the side of the second (meth)acrylic resin film. The layer structure of the polarizing plate 6 is the first (meth)acrylic resin film (the first thermoplastic resin film) / the first adhesive layer composed of the adhesive 1 / the polarizing film 2 / the first adhesive layer composed of the adhesive 1. 2. Adhesive layer/2nd (meth)acrylic resin film (2nd thermoplastic resin film).

(5) Thickness of the adhesive layer (after curing)

Using a microtome (“Ultramicrotome EM UC6rt” manufactured by Hitachi High Technologies Co., Ltd.) of the produced polarizing plate, a sample for cross-section observation was produced. The obtained sample for cross-section observation was observed with a scanning electron microscope (Model JSM-5510 manufactured by Nippon Electron Datum Co., Ltd.), and the thickness of the adhesive layer was determined.

The thickness of the thermoplastic resin film, the polarizing film and the adhesive layer constituting the polarizing plate, the tensile elastic modulus of the thermoplastic resin film and the polarizing film (transmission axis direction) at 80°C, and the storage elastic modulus of the adhesive layer at 80°C were measured. The numbers are summarized in Table 2.

In addition, the structure of the polarizing plate and the rigidity based on the above formulae (Ia), (Ib), (Ic), (IIa), (IIb) of each thin film and adhesive layer constituting the polarizing plate are summarized in Table 3.

(Evaluation of thermal shock resistance)

The polarizing plate produced above was cut into a size of 170 mm (the direction of the transmission axis of the polarizing film)×110 mm (the direction of the absorption axis of the polarizing film). An adhesive layer was laminated on the obtained polarizing plate sample, and the polarizing plate sample was attached to a glass plate through the adhesive layer. A thermal shock test (thermal shock test) was performed on the polarizing plate sample attached to the glass plate. The thermal shock test is performed by taking the polarizing plate sample attached to the glass plate at -30°C for 1 hour, then raising the temperature to 70°C and holding it for 1 hour as one cycle, and repeating this for a total of 100 cycles. implement. Five polarizing plate samples were prepared for each Example/Comparative Example, and the thermal shock test was performed 5 times using these polarizing plate samples. Evaluation of thermal shock resistance was performed by calculating the ratio of the number of samples in which cracks (cracks) were observed in the polarizing film after the test to the number of all samples (5). The evaluation results are shown in Table 4 together with the value of the product of the rigidity represented by the above formula (I) and formula (II).

<Example 4: Production of polarizing plate 7>

On the second (meth)acrylic resin film (without the ultraviolet absorber), an adhesive 1 is applied using an adhesive coating apparatus to form an adhesive layer, and the polarizing film 1 is bonded via the adhesive layer. The cumulative light intensity of UVA in the UV wavelength region from the side of the (meth)acrylic resin film (excluding the ultraviolet absorber) is about 350 mJ/cm ² (measured value using a measuring device: UV Power Puck II manufactured by Fusion UV Co., Ltd.) In this way, ultraviolet rays are irradiated to harden the adhesive layer, and a polarizing plate 7 is obtained. The layer structure of the polarizing plate 7 is the second (meth)acrylic resin film (the first thermoplastic resin film)/the first adhesive layer composed of the adhesive 1/the polarizing film 1 .

<Example 5: Production of polarizing plate 8>

On a cyclic polyolefin-based resin film (retardation film "ZEONOR" manufactured by Japan Zeon Co., Ltd.), an adhesive agent 1 is applied using an adhesive agent coating device to form an adhesive agent layer, and the polarized light is pasted through the adhesive agent layer. Film 1. Ultraviolet rays were irradiated from the cyclic polyolefin resin film side so that the cumulative light intensity of UVA in the UV wavelength region became about 350 mJ/cm ² (measured value using a measuring device: UV Power Puck II manufactured by Fusion UV Co., Ltd.). The agent layer was hardened, and a polarizing plate 8 was obtained. The layer structure of the polarizing plate 8 is a cyclic polyolefin-based resin film (first thermoplastic resin film)/first adhesive layer composed of an adhesive 1/polarizing film 1 .

The structure of the polarizing plate and the rigidity of each thin film and adhesive layer constituting the polarizing plate based on the above formulae (Ia), (Ib), (Ic), (IIa), and (IIb) are summarized in Table 5.

The same evaluation as the evaluation of thermal shock resistance described above was performed. The results are shown in Table 6.

10‧‧‧Polarizing Film

15‧‧‧First Adhesive Layer

21‧‧‧The first thermoplastic resin film

22‧‧‧Second thermoplastic resin film

25‧‧‧Second Adhesive Layer

Claims (10)

A polarizing plate comprising a first thermoplastic resin film, a first adhesive layer, and a polarizing film in this order, wherein the first adhesive layer is a cured product layer of an active energy ray-curable adhesive containing a cation-curable component , the cationic curable component contains an epoxy compound and an oxetane compound, the rigidity of the first thermoplastic resin film is R _1t [MPa·mm ³ ], and the rigidity of the first adhesive layer is R _1a [MPa·mm ³ ], and when the rigidity of the polarizing film is R _p [MPa·mm ³ ], the product of the rigidity represented by the following formula (I) is 5.0×10 ^-8 (MPa·mm ³ ) ³ or more: product of rigidity=R _1t ×R _1a ×R _p (I), where rigidity R _1t is represented by the following formula (Ia): rigidity R _1t =(1st thermoplastic resin film at 80° C. The tensile modulus of elasticity [MPa]) × (thickness of the first thermoplastic resin film [mm]) ³ (Ia), the rigidity R _1a is represented by the following formula (Ib): Rigidity R _1a =(1st adhesive agent) The storage elastic modulus of the layer at 80°C [MPa]) × (the thickness of the first adhesive layer [mm]) ³ (Ib), the rigidity R _p is represented by the following formula (Ic): rigidity R _p = (polarized light Tensile modulus of elasticity at 80°C in the penetration axis direction of the film [MPa])×(thickness of the polarizing film [mm]) ³ (Ic). The polarizing plate according to claim 1, wherein the first The thermoplastic resin film is composed of a thermoplastic resin selected from the group consisting of polyester-based resins, polycarbonate-based resins, polyolefin-based resins, (meth)acrylic-based resins, and cellulose ester-based resins. The polarizing plate according to claim 1 or 2, comprising the first thermoplastic resin film, the first adhesive layer, the polarizing film, the second adhesive layer, and the second thermoplastic resin film in this order. The polarizing plate according to claim 3, wherein the rigidity of the second adhesive layer is R _2a [MPa·mm ³ ], and the rigidity of the second thermoplastic resin film is R _2t [ MPa·mm ³ ], the product of rigidity represented by the following formula (II) is 5.0×10 ^-8 (MPa·mm ³ ) ³ or more: product of rigidity=R _p ×R _2a ×R _2t (II), Here, rigidity R _2a is represented by the following formula (IIa): rigidity R _2a =(storage modulus of elasticity of the second adhesive layer at 80° C. [MPa])×(thickness of the second adhesive layer [mm] ]) ³ (IIa), the rigidity R _2t is represented by the following formula (IIb): Rigidity R _2t = (the tensile modulus of elasticity of the second thermoplastic resin film at 80° C. [MPa]) × (the second thermoplastic resin film thickness [mm]) ³ (IIb). The polarizing plate according to claim 3, wherein the second adhesive layer is a cured product layer of an active energy ray-curable adhesive. The polarizing plate according to claim 5, wherein the active energy ray-curable adhesive contains a cation-curable component. The polarizing plate according to claim 3, wherein the second The thermoplastic resin film is composed of a thermoplastic resin selected from the group consisting of polyester-based resins, polycarbonate-based resins, polyolefin-based resins, (meth)acrylic-based resins, and cellulose ester-based resins. The polarizing plate according to claim 3, wherein the first thermoplastic resin film is made of (meth)acrylic resin, and the second thermoplastic resin film is made of polyolefin resin or cellulose ester Made of resin. The polarizing plate according to claim 3, wherein both the first thermoplastic resin film and the second thermoplastic resin film are made of (meth)acrylic resin. The polarizing plate according to claim 3, wherein at least one of the first thermoplastic resin film and the second thermoplastic resin film is a retardation film.

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