Polarizing film laminate

Abstract

To provide a polarization film laminated body having a polarization film excellent in suppressing effect of lowering of single transmittance under high temperature environment.SOLUTION: In a polarization film laminated body, a first substrate, a polarization film, and a second substrate are laminated in this order. The first substrate and the second substrate have moisture permeability of 300g / m2 24h or less. At least one layer existing between the first substrate and the second substrate contains a water-soluble radical scavenger.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a polarizing film laminate.

Background Art

[0002] Conventionally, as a polarizing film used in various image display devices such as liquid crystal display devices and organic EL display devices, a polyvinyl alcohol-based film that has both high transmittance and high polarization degree and is dyed (contains dichroic substances such as iodine and dichroic dyes) has been used. The polarizing film is manufactured by subjecting a polyvinyl alcohol-based film to various treatments such as swelling, dyeing, crosslinking, and stretching in a bath, then performing a washing treatment, and then drying.

[0003] In recent years, such various image display devices are used not only in mobile devices such as mobile phones and tablet terminals but also in in-vehicle image display devices such as car navigation devices and rear monitors, and their applications are expanding. Along with this, a polarizing film laminate having a polarizing film is required to have higher durability in a more severe environment (for example, a high-temperature environment) than conventionally required, and a polarizing film laminate aimed at ensuring such durability has been proposed (Patent Documents 2-3).

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] In the above-described in-vehicle image display device, due to the recent development of autonomous driving technology, the display design has become more irregular and larger. Along with such changes in the display design, means for further improving the durability in a high-temperature environment are required in the polarizing film laminate.

[0006] In view of the above circumstances, an object of the present invention is to provide a polarizing film laminate having an excellent effect of suppressing a decrease in the single transmittance in a high-temperature environment.

Means for Solving the Problems

[0007] That is, the present invention is a polarizing film laminate in which a first substrate, a polarizing film, and a second substrate are laminated in this order, and the first substrate and the second substrate have a moisture permeability of 300 g / (m 2 ·24 h) or less, and relates to a polarizing film laminate in which at least one layer present between the first substrate and the second substrate contains a water-soluble radical scavenger.

Effects of the Invention

[0008] Although there are some unclear parts in the detailed mechanism of the action of the effects in the polarizing film laminate of the present invention, it is presumed as follows. However, the present invention is not construed as being limited to this action mechanism.

[0009] The polarizing film laminate of the present invention is a polarizing film laminate in which a first substrate, a polarizing film, and a second substrate are laminated in this order, and the first substrate and the second substrate have a moisture permeability of 300 g / (m 2 ·24 h) or less, and at least one layer present between the first substrate and the second substrate contains a water-soluble radical scavenger. The polarizing film is presumed to undergo polyene formation accompanied by radical generation due to the deterioration of polyvinyl alcohol in a high-temperature environment, resulting in a decrease in the single transmittance. On the other hand, when the polarizing film laminate of the present invention is exposed to a high-temperature environment, the water-soluble radical scavenger contained in at least one layer present between the first substrate and the second substrate has a moisture permeability of 300 g / (m 2·Since it can efficiently capture radicals generated in the polarizing film by staying (moving) between the first substrate and the second substrate together with the moisture contained in the polarizing film, it is excellent in the effect of suppressing the decrease in the single transmittance in a high-temperature environment.

Embodiments for Carrying Out the Invention

[0010] The polarizing film laminate of the present invention is a polarizing film laminate in which a first substrate, a polarizing film, and a second substrate are laminated in this order, and the first substrate and the second substrate have a moisture permeability of 300 g / (m 2 ·24h) or less, and at least one layer present between the first substrate and the second substrate contains a water-soluble radical scavenger.

[0011] <Water-soluble radical scavenger> The water-soluble radical scavenger is preferably a compound that can be dissolved in 1 part by weight or more with respect to 100 parts by weight of water at 25°C, more preferably a compound that can be dissolved in 2 parts by weight or more with respect to 100 parts by weight of water at 25°C, and even more preferably a compound that can be dissolved in 5 parts by weight or more with respect to 100 parts by weight of water at 25°C, from the viewpoint of being easily transferred to the moisture in the polarizing film. The water-soluble radical scavenger may be used alone or in combination of two or more.

[0012] The water-soluble radical scavenger is presumed to be able to suppress the polyene formation of the polarizing film in a high-temperature environment. Examples of the water-soluble radical scavenger include compounds having a radical scavenging function such as hindered phenol-based, hindered amine-based, phosphorus-based, sulfur-based, benzotriazole-based, benzophenone-based, hydroxylamine-based, salicylic acid ester-based, and triazine-based compounds. The water-soluble radical scavenger is preferably, from the viewpoint of the radical species generated in the polarizing film, for example, a nitroxyl radical or a compound having a nitroxide group.

[0013] As the nitroxy radical or the compound having a nitroxide group, from the viewpoint of having a radical that is relatively stable at room temperature in air, N-oxyl compounds (as a functional group, C-N(-C)-O · compounds having (O · represents an oxy radical)) can be mentioned, and known ones can be used. Examples of the N-oxyl compound include compounds having an organic group with the following structure. [Chemical formula] (In general formula (1), R 1 represents an oxy radical, and R 2 to R 5 each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, and n represents 0 or 1.) In addition, the left side of the dotted line part in general formula (1) represents an arbitrary organic group.

[0014] Examples of the compound having the above organic group include compounds represented by the following general formulas (2) to (5). [Chemical formula] (In general formula (2), R 1 to R 5 , and n are the same as above, and R 6 represents a hydrogen atom, or an alkyl group, an acyl group, or an aryl group having 1 to 10 carbon atoms, and n represents 0 or 1.) [Chemical formula] (In general formula (3), R 1 to R 5 , and n are the same as above, and R 7 and R 8 each independently represents a hydrogen atom, or an alkyl group, an acyl group, or an aryl group having 1 to 10 carbon atoms.) [Chemical formula] (In general formula (4), R 1 to R 5, and n is the same as above, and R 9 from R 11 independently represents a hydrogen atom, or an alkyl group, an acyl group, an amino group, an alkoxy group, a hydroxy group, or an aryl group having 1 to 10 carbon atoms.)

Chemical formula

[0015] In the above General Formulas (1) to (5), R 2 from R 5 is preferably an alkyl group having 1 to 6 carbon atoms, more preferably an alkyl group having 1 to 3 carbon atoms, from the viewpoint of availability. Also, in General Formula (2), from the viewpoint of availability, R 6 is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom. Also, in General Formula (3), from the viewpoint of availability, R 7 and R 8 are preferably independently a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, more preferably a hydrogen atom. Also, in General Formula (4), from the viewpoint of availability, R 9 from R 11 is preferably a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Also, in General Formula (5), from the viewpoint of availability, R 12 is preferably a hydroxy group, an amino group, or an alkoxy group. In the above General Formulas (1) to (5), n is preferably 1 from the viewpoint of availability.)

[0016] In addition, examples of the N-oxyl compound include N-oxyl compounds described in JP-A-2003-64022, JP-A-11-222462, JP-A-2002-284737, International Publication No. 2016 / 047655, and the like.

[0017] Examples of the nitroxy radical or the compound having a nitroxide group include the following compounds. [Chemical formula] (In General Formula (6), R represents a hydrogen atom, an alkyl group having 1 to 10 carbon atoms, an acyl group, or an aryl group.) [Chemical formula] [Chemical formula]

[0018] In addition, from the viewpoint that the water-soluble radical scavenger can efficiently capture radicals generated in the polarizing film by the water-soluble radical scavenger contained in at least one layer existing between the first substrate and the second substrate staying (moving) between the first substrate and the second substrate together with the moisture contained in the polarizing film in a high-temperature environment, the molecular weight is preferably 1000 or less, more preferably 500 or less, and even more preferably 300 or less.

[0019] [Polarizing film] The polarizing film is formed by adsorbing and orienting a dichroic substance such as iodine or a dichroic dye on a polyvinyl alcohol-based film. From the viewpoint of the initial polarization performance of the polarizing film, an iodine-based polarizing film containing iodine as the dichroic substance is preferable.

[0020] The polyvinyl alcohol (PVA)-based film has translucency in the visible light region, and those that disperse and adsorb dichroic substances such as iodine and dichroic dyes can be used without particular limitation. Examples of the material of the polyvinyl alcohol-based film include polyvinyl alcohol or its derivatives. Examples of the derivatives of polyvinyl alcohol include those modified with polyvinyl formal, polyvinyl acetal; olefins such as ethylene and propylene; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and their alkyl esters, acrylamide, and the like. The polyvinyl alcohol preferably has an average degree of polymerization of about 100 to 10,000, more preferably about 1,000 to 10,000, and even more preferably about 1,500 to 4,500. Further, the polyvinyl alcohol preferably has a saponification degree of about 80 to 100 mol%, more preferably about 95 mol% to 99.95 mol%. The average degree of polymerization and the saponification degree can be determined according to JIS K 6726.

[0021] The polarizing film is obtained by a conventional method for producing a polarizing film. For example, it is obtained by subjecting the polyvinyl alcohol-based film to an optional swelling step and washing step, and at least a dyeing step, a crosslinking step, and a stretching step. When the polarizing film contains the water-soluble radical scavenger, the treatment bath in any one or more of the treatment steps of the swelling step, the washing step, the dyeing step, the crosslinking step, and the stretching step may contain the water-soluble radical scavenger.

[0022] From the viewpoint of improving the initial polarization degree of the polarizing film, the thickness of the polarizing film is preferably 1 μm or more, more preferably 2 μm or more, and from the viewpoint of preventing warping of the panel, it is preferably 20 μm or less, more preferably 15 μm or less, still more preferably 10 μm or less, and even more preferably 8 μm or less. In particular, in order to obtain a polarizing film with a thickness of about 8 μm or less, the following method for manufacturing a thin polarizing film can be applied, which uses, as the polyvinyl alcohol-based film, a laminate including a polyvinyl alcohol-based resin layer formed on a thermoplastic resin substrate.

[0023] The polarizing film (thin polarizing film) is obtained by a conventional method for manufacturing a polarizing film. For example, a step of forming a polyvinyl alcohol-based resin layer (PVA-based resin layer) containing a polyvinyl alcohol-based resin (PVA-based resin) on one side of a long thermoplastic resin substrate to prepare a laminate, and while transporting the obtained laminate in the longitudinal direction, subjecting the laminate to an optional insolubilization treatment step, crosslinking treatment step, and washing treatment step, and at least an air-assisted stretching treatment step, dyeing treatment step, and underwater stretching treatment step. When the polarizing film contains the water-soluble radical scavenger, the treatment bath in any one or more of the treatment steps of the insolubilization treatment step, crosslinking treatment step, washing treatment step, dyeing treatment step, and underwater stretching treatment step may contain the water-soluble radical scavenger.

[0024] <First Substrate and Second Substrate> The first substrate and the second substrate have a moisture permeability of 300 g / (m 2· If it is below 300 g / (m²·24 h), there is no particular limitation, and for example, an organic substrate such as a transparent protective film or a retardation film used in a polarizing film can be used. The first substrate and the second substrate may be the same or different. The moisture permeability can be calculated by measuring the weight increase of calcium chloride before and after setting a sample cut to a diameter of 60 mm in a moisture permeation cup containing about 15 g of calcium chloride, placing it in a constant temperature chamber at a temperature of 40 °C and a humidity of 90% R.H., and leaving it for 24 hours in accordance with the moisture permeability test (cup method) of JIS Z0208.

[0025] Examples of the material constituting the transparent protective film include cellulose ester resins, polycarbonate resins, (meth)acrylic resins, cyclic polyolefin resins, polyester resins, and the like. Examples of the retardation film include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, an alignment film of a liquid crystal polymer, and a film supporting an alignment layer of a liquid crystal polymer. In addition, the transparent protective film and the retardation film may be provided with one or more other layers such as a hard coat layer, an antireflection layer, an anti-sticking layer, a diffusion layer or an antiglare layer; and optical layers used for forming an image display device such as a reflector, a transflective plate, a retardation plate (including wavelength plates such as 1 / 2 and 1 / 4), and a viewing angle compensation film.

[0026] From the viewpoint that at least one water-soluble radical scavenger contained in at least one layer existing between the first substrate and the second substrate can efficiently capture radicals generated in the polarizing film by staying (moving) between the first substrate and the second substrate together with the moisture contained in the polarizing film in a high-temperature environment, the total moisture permeability of the first substrate and the second substrate is preferably 300 g / (m²·24 h) or less, more preferably 200 g / (m²·24 h) or less, and even more preferably 100 g / (m²·24 h) or less. 2 ·24 h) or less, 2 ·24 h) or less is more preferable, and 100 g / (m²·24 h) or less 2· It is more preferably 100 g / (m 2 ·24 h) or less, preferably 50 g / (m 2 ·24 h) or less, more preferably 20 g / (m 2 ·24 h) or less.

[0027] <The layer existing between the first substrate and the second substrate> From the viewpoint that the total thickness of the layers existing between the first substrate and the second substrate allows the water-soluble radical scavenger contained in at least one of the layers existing between the first substrate and the second substrate to stay (move) between the first substrate and the second substrate together with the moisture contained in the polarizing film, thereby efficiently scavenging the radicals generated in the polarizing film, the total thickness is preferably 50 μm or less, more preferably 30 μm or less, and even more preferably 20 μm or less under high-temperature environments.

[0028] From the viewpoint that the total thickness of the layers existing between the first substrate and the second substrate allows the water-soluble radical scavenger contained in at least one of the layers existing between the first substrate and the second substrate to stay (move) between the first substrate and the second substrate together with the moisture contained in the polarizing film, thereby efficiently scavenging the radicals generated in the polarizing film, the total thickness is preferably 3 times or less, more preferably 2.5 times or less, and even more preferably 2 times or less with respect to the thickness of the polarizing film.

[0029] The layer existing between the first substrate and the second substrate includes, in addition to the polarizing film, an adhesive layer, an adhesive layer, a functional layer, and the like.

[0030] As the adhesive for forming the adhesive layer, various adhesives used in polarizing films can be applied, for example, acrylic adhesives. Also, as the adhesive for forming the adhesive layer, various adhesives used in polarizing films can be applied, for example, polyvinyl alcohol-based adhesives, active energy ray-curable adhesives, etc. As the active energy ray-curable adhesive, for example, (meth)acrylate-based adhesives can be mentioned. As the curable components in the (meth)acrylate-based adhesive, for example, compounds having a (meth)acryloyl group and compounds having a vinyl group can be mentioned. Examples of the compound having a (meth)acryloyl group include alkyl (meth)acrylates such as linear alkyl (meth)acrylates having 1 to 20 carbon atoms, alicyclic alkyl (meth)acrylates, and polycyclic alkyl (meth)acrylates; hydroxyl group-containing (meth)acrylates; epoxy group-containing (meth)acrylates such as glycidyl (meth)acrylate, etc. The (meth)acrylate-based adhesive may contain nitrogen-containing monomers such as hydroxyethyl (meth)acrylamide, N-methylol (meth)acrylamide, N-methoxymethyl (meth)acrylamide, N-ethoxymethyl (meth)acrylamide, (meth)acrylamide, and (meth)acryloylmorpholine. The (meth)acrylate-based adhesive may contain polyfunctional monomers such as tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, dioxane glycol diacrylate, and EO-modified diglycerin tetraacrylate as crosslinking components. Also, compounds having an epoxy group or an oxetanyl group can be used as cationic polymerization-curable adhesives. The compound having an epoxy group is not particularly limited as long as it has at least two epoxy groups in the molecule, and various generally known curable epoxy compounds can be used.

[0031] As the functional layer, there are a blocking layer having a function to prevent impurities such as oligomers and ions eluted from a transparent protective film or the like from migrating (invading) into the polarizing film; a refractive index adjustment layer provided to suppress a decrease in transmittance due to reflection between layers with different refractive indices such as a transparent protective film and a polarizing film; a reinforcing layer for preventing the polarizing film from being bent; a liquid crystal coating layer having a retardation function, and the like. Note that, from the viewpoint of efficiently capturing radicals generated in the polarizing film in a high-temperature environment, it is preferable to add the water-soluble radical scavenger to a layer containing a PVA-based resin such as a polarizing film, an aqueous adhesive, or a functional layer (reinforcing layer).

[0032] The first substrate, the second substrate, and the layer present between the first substrate and the second substrate may be surface-modified or easily adhered.

Example

[0033] The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to only these examples.

[0034] <Example 1> <Production of polarizing film> On one side of an amorphous isophthalic acid copolymer polyethylene terephthalate (IPA copolymer PET) film (thickness: 100 μm) substrate with a water absorption rate of 0.75% and a Tg of 75°C, corona treatment was performed. On this corona-treated surface, an aqueous solution containing polyvinyl alcohol (degree of polymerization 4200, saponification degree 99.2 mol%) and acetoacetyl-modified PVA (degree of polymerization 1200, degree of acetoacetyl modification 4.6%, saponification degree 99.0 mol% or more, manufactured by Nippon Synthetic Chemical Industry Co., Ltd., trade name "Gosefimer Z200") in a ratio of 9:1 was applied and dried at 25°C to form a PVA-based resin layer with a thickness of 11 μm, and a laminate was produced. The obtained laminate was uniaxially stretched 2.0 times in the longitudinal direction (lengthwise direction) between rolls with different peripheral speeds in an oven at 120°C (air-assisted stretching treatment). Next, the laminate was immersed in an insolubilization bath (an aqueous boric acid solution obtained by blending 4 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30°C for 30 seconds (insolubilization treatment). Next, it was immersed in a dyeing bath at a liquid temperature of 30°C while adjusting the iodine concentration and immersion time so that the polarizing film had a predetermined transmittance (dyeing treatment). Next, it was immersed in a cross-linking bath (an aqueous boric acid solution obtained by blending 3 parts by weight of potassium iodide and 3 parts by weight of boric acid with respect to 100 parts by weight of water) at a liquid temperature of 30°C for 30 seconds (cross-linking treatment). Then, while immersing the laminate in an aqueous boric acid solution (an aqueous solution obtained by blending 4 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) at a liquid temperature of 70°C, uniaxial stretching was performed in the longitudinal direction (lengthwise direction) between rolls with different peripheral speeds so that the total stretching ratio was 5.5 times (stretching treatment in water). Then, the laminate was immersed in a washing bath at a liquid temperature of 30°C (an aqueous solution with a potassium iodide concentration of 3% by weight and a concentration of the compound represented by the following general formula (9) as a water-soluble radical scavenger of 1% by weight) (washing treatment). Then, while drying in an oven maintained at 90°C, it was brought into contact with a SUS heating roll with a surface temperature maintained at 75°C for about 2 seconds (dry shrinkage treatment). Thus, an optical film laminate containing a polarizing film with a thickness of 5.4 μm was obtained. The content of the radical scavenger in the polarizing film determined by the following measurement method was 0.19% by weight.

Chemical formula

[0035] [Method for Measuring Content (wt%) of Water-Soluble Radical Scavenger in Polarizing Film] Approximately 20 mg of the polarizing film was sampled and quantified, heated and dissolved in 1 mL of water, diluted with 4.5 mL of methanol, the resulting extract was filtered through a membrane filter, and the concentration of the water-soluble radical scavenger in the filtrate was measured using HPLC (ACQUITY UPLC H-class Bio manufactured by Waters).

[0036] <Fabrication of Polarizing Film Laminate> As the adhesive, an aqueous solution containing a polyvinyl alcohol resin containing an acetoacetyl group (average degree of polymerization: 1,200, degree of saponification: 98.5 mol%, degree of acetoacetylation: 5 mol%) and methylol melamine in a weight ratio of 3:1 was used. On the polarizing film surface of the optical film laminate obtained above, as the first substrate, a 30-μm-thick transparent protective film (moisture permeability: 125 g / (m 2 ·24 h)) made of a (meth)acrylic resin (modified acrylic polymer having a lactone ring structure) was laminated using a roll laminator through the above adhesive (dry film thickness: 0.1 μm), and then heated and dried in an oven (temperature: 60°C, time: 4 minutes). Next, the polyethylene terephthalate film was peeled off, and on the peeled surface, as the second substrate, a 27-μm-thick cycloolefin resin film (ZF14 manufactured by Nippon Zeon Co., Ltd., moisture permeability: 10 g / (m 2 ·24 h)) was adhered via an ultraviolet-curable adhesive. Then, UV light was irradiated from the second substrate surface to cure the adhesive, and a polarizing film laminate was fabricated. The details of the ultraviolet-curable adhesive are as follows. 40 parts by weight of N-hydroxyethylacrylamide (HEAA), 60 parts by weight of acryloylmorpholine (ACMO), and 3 parts by weight of a photoinitiator “IRGACURE 819” (manufactured by BASF) were mixed to prepare the adhesive. The adhesive was applied onto the polarizing film so that the thickness of the cured adhesive layer would be 1.0 μm, and ultraviolet light was irradiated as the active energy ray to cure the adhesive. The ultraviolet irradiation was performed using a gallium-encapsulated metal halide lamp, irradiation device: Light HAMMER10 manufactured by Fusion UV Systems, Inc., bulb: V bulb, peak illuminance: 1600 mW / cm2 , Integrated irradiation dose of 1000 / mJ / cm 2 (wavelength 380 - 440 nm) was used, and the ultraviolet illuminance was measured using the Sola-Check system manufactured by Solatell.

[0037] [Preparation of Acrylic Adhesive] A monomer mixture containing 99 parts of butyl acrylate and 1 part of 4-hydroxybutyl acrylate was charged into a four-necked flask equipped with a stirring blade, a thermometer, a nitrogen gas inlet tube, and a cooler. Further, 0.1 part of 2,2'-azobisisobutyronitrile as a polymerization initiator was charged together with 100 parts of ethyl acetate per 100 parts of the monomer mixture (solid content). After introducing nitrogen gas with gentle stirring for nitrogen substitution, the polymerization reaction was carried out for 8 hours while maintaining the liquid temperature in the flask at around 55 °C to prepare a solution of an acrylic polymer with a weight average molecular weight (Mw) of 1.8 million. Then, 0.02 part of an isocyanate crosslinking agent (manufactured by Tosoh Corporation, trade name "Takenate D110N", trimethylolpropane / xylene diisocyanate adduct) and 0.2 part of a silane coupling agent (manufactured by Shin-Etsu Chemical Co., Ltd., trade name "X-41-1056") were blended per 100 parts of the solid content of the obtained acrylic polymer solution to prepare a solution of an acrylic adhesive composition.

[0038] [Preparation of Polarizing Film Laminate with Adhesive] The solution of the acrylic adhesive composition obtained above was applied to one side of a polyethylene terephthalate film (manufactured by Mitsubishi Chemical Polyester Film, trade name "MRF38", separator film) treated with a silicone-based release agent so that the thickness of the dried adhesive layer would be 20 μm, and dried at 90 °C for 1 minute to form an adhesive layer on the surface of the separator film. Next, the adhesive layer formed on the separator film was transferred to one surface of the polarizing film laminate prepared above to prepare a polarizing film laminate with an adhesive layer.

[0039] [Evaluation of Single Transmittance under High Temperature Environment] The polarizing film laminate with an adhesive layer obtained above was cut into a size of 45×40 mm so that the absorption axis of the polarizing film was parallel to the long side, and a glass plate (EG-XG manufactured by Hirata Special Glass Co., Ltd., 50×45 mm, thickness 0.7 mm) was bonded through the adhesive layer, and autoclave treatment was performed at 50 °C and 0.5 MPa for 15 minutes to produce a laminate. The obtained laminate was left standing in a hot air oven at a temperature of 105 °C for 500 hours, and the single transmittance (ΔTs) before and after charging (heating) was measured. The single transmittance was obtained by measuring the optical properties using an ultraviolet-visible spectrophotometer (manufactured by Otsuka Electronics Co., Ltd., "LPF-200"). The single transmittance is the Y value with visual sensitivity correction according to the 2-degree field of view (C light source) of JlS Z 8701-1982. The measurement wavelength is 380 to 780 nm (every 5 nm). ΔTs(%) = Ts 500 - Ts0 Here, Ts0 is the single transmittance of the laminate before heating, and Ts 500 is the single transmittance of the laminate after heating for 500 hours. The results are shown in Table 1. It is preferable that 5 ≧ ΔTs(%) ≧ 0, and more preferably 3 ≧ ΔTs(%) ≧ 0.

[0040] <Example 2> In the production of the polarizing film laminate, as the first base material, a cycloolefin-based film with a thickness of 23 μm (ZF12 manufactured by Nippon Zeon Co., Ltd., moisture permeability of 10 g / (m 2 ·24 h)) was used, and a polarizing film laminate with an adhesive layer was produced in the same manner as in Example 1, except that the ultraviolet curable adhesive described in Example 1 was used as the adhesive and bonded.

[0041] <Example 3> In the production of the polarizing film, without adding the water-soluble radical scavenger represented by the general formula (9) to the cleaning bath, and in the production of the polarizing film laminate, the water-soluble radical scavenger represented by the general formula (9) was added to the adhesive used for laminating the polarizing film and the first substrate so that the weight ratio to the polyvinyl alcohol resin was 4:3, and potassium hydroxide was added so that the molar ratio to the water-soluble radical scavenger was 1:1 to adjust the pH (neutralize), except for this, a polarizing film laminate with an adhesive layer was produced by the same operation as in Example 1.

[0042] <Example 4> In the production of the polarizing film, without adding the water-soluble radical scavenger represented by the general formula (9) to the cleaning bath, and in the production of the polarizing film laminate, the exposed surface of the polarizing film was subjected to corona treatment, and a resin composition (an aqueous solution containing a polyvinyl alcohol resin (manufactured by Nippon Vinylon Co., Ltd., trade name: JC-25H) with a polymerization degree of 2500 and a saponification degree of 99.8 mol% dissolved in pure water and the water-soluble radical scavenger represented by the above general formula (9) in a weight ratio of 3:1 after drying and forming a film (solid content 25% by weight)) was applied with a wire bar so that the thickness after drying was 0.8 μm, and then dried at 60°C for 5 minutes to form a functional layer (reinforcing layer) on the polarizing film. Then, a polarizing film laminate with an adhesive layer was produced by the same operation as in Example 1, except that the first substrate was laminated through an aqueous adhesive.

[0043] <Comparative Example 1> In the production of the polarizing film, a polarizing film laminate with an adhesive layer was produced by the same operation as in Example 1, except that the compound represented by the general formula (9) was not added to the cleaning bath.

[0044] <Comparative Example 2> In the production of the polarizing film, a polarizing film laminate with an adhesive layer was produced by the same operation as in Example 2, except that the compound represented by the general formula (9) was not added to the cleaning bath.

[0045] Using the polarizing film laminate with an adhesive layer of each of the examples and comparative examples obtained above, the above [evaluation of the single transmittance under high-temperature environment] was conducted. The results are shown in Table 1.

[0046]

Table 1

Claims

**Claim 1** A polarizing film laminate in which a first substrate, a polarizing film, and a second substrate are laminated in this order, The first substrate and the second substrate have a moisture permeability of 300 g / (m ２ ・24 h) or less, wherein at least one layer present between the first substrate and the second substrate contains a water-soluble radical scavenger, and the water-soluble radical scavenger is a nitroxyl radical or a compound having a nitroxide group. A polarizing film laminate characterized by this. **Claim 2** The polarizing film laminate according to claim 1, wherein the total thickness of the layers present between the first substrate and the second substrate is 50 μm or less. **Claim 3** The polarizing film laminate according to claim 1 or 2, wherein at least one layer present between the first substrate and the second substrate is one or more selected from the group consisting of the polarizing film, an adhesive layer, an adhesive layer, and a functional layer. **Claim 4** The polarizing film laminate according to any one of claims 1 to 3, wherein the thickness of the polarizing film is 20 μm or less. **Claim 5** The polarizing film laminate according to any one of claims 1 to 4, wherein the polarizing film is an iodine-based polarizing film in which iodine is adsorbed and oriented.

Images