TW202309625A - Resin film for polarizing plates, method for producing said resin film, polarizing plate, and display device - Google Patents

Abstract

The present invention addresses the problem of providing: a resin film for polarizing plates that, when used in a polarizing plate in a display device, suppresses contrast deterioration and reductions in adhesive strength caused by the heat generated by semiconductor substrates; and a polarizing plate and display device comprising this resin film for polarizing plates. The resin film for polarizing plates according to the present invention is a resin film for polarizing plates that is used in polarizing plates comprising at least an iodine-containing polarizer layer, wherein the resin film for polarizing plates characteristically comprises at least a thermoplastic resin and an iodine migration inhibitor and has a film thickness of at least 1 [mu]m but less than 15 [mu]m.

Description

Resin film for polarizing plate, method for producing same, polarizing plate, and display device

The present invention relates to a resin film for polarizing plates, a manufacturing method thereof, a polarizing plate, and a display device. More specifically, it relates to a resin film for a polarizing plate capable of suppressing a reduction in adhesive force and a deterioration in contrast due to heat generation of a semiconductor substrate when used for a polarizing plate in a display device, a method for producing the same, and further includes the polarizing plate. Resin film polarizer and display device.

In recent years, the introduction and popularization of the 5th generation mobile communication system (5G) is expected, and the development of communication equipment corresponding to 5G is progressing. In 5G, compared with the previous generation of 4G, the communication speed has been greatly increased. For 5G-compatible communication equipment, high-speed and large-capacity information processing is required, and there is a concern that the durability of the accompanying equipment will decrease due to heat generation.

Regarding a display device using a polarizer layer dyed with iodine (hereinafter, also referred to as "iodine") on a polyvinyl alcohol (PVA) film, it is known that the number of times of color switching or pixels due to high-definition As the number increases, the semiconductor substrate heats up, and the contrast decreases due to the deterioration of the color tone of the display.

As the main reason for the decrease in contrast, it is considered that the iodine system aligned in the PVA iodine-dyed polarizer layer (hereinafter also simply referred to as “polarizer layer”) moves, and the polarizing performance of the polarizer layer decreases. In addition, usually the polarizer layer is bonded with protective layers on both sides through the adhesive layer. Therefore, it is considered that the mobile iodine will enter into the protective layer, reducing the adhesive force between the protective layer and the polarizer layer, and further promoting the reduction of contrast.

Patent Document 1 discloses a technology of a cellulose acyl compound film containing an iodine uptake reducing agent and an acidic component as a polarizer protective film that has high transparency even in a film and can suppress deterioration of polarizing performance under high temperature and high humidity. However, in the high-temperature environment of communication equipment corresponding to 5G, the movement of polyiodine (I ₃ ^- or I ₅ ^- ) becomes more active and easy to move, so it is known that polyiodine and thin film The acidic part of the reactant precipitates out, and the contrast decreases.

Patent Document 2 discloses the technology of an optical compensation sheet that does not cause light leakage due to thermal strain, suppresses changes in optical characteristics caused by environmental conditions, and makes the resulting temperature distribution uniform. In addition, the cellulose acetate film contained in this optical compensation sheet can make the thermal conductivity more than 1W/(m･K) by further containing high thermal conductivity particles, showing that the higher the thermal conductivity, the better the thermal conductivity. Excellent effect. However, in this technology, the reduction in contrast cannot be suppressed under the higher temperature environment of communication equipment compatible with 5G, and there is room for improvement. [Prior Art Literature] [Patent Document]

[Patent Document 1] Japanese Unexamined Patent Publication No. 2014-80571 [Patent Document 2] Japanese Patent No. 4285919

[Problems to be Solved by the Invention]

The present invention was made in view of the above-mentioned problems and situations, and the problem to be solved is to provide a resin for polarizing plates that can suppress the decrease in adhesive force and contrast deterioration caused by heat generation of semiconductor substrates when used in polarizing plates in display devices. A film, a method for producing the same, and a polarizing plate and a display device using the polarizing plate resin film. [means to solve the problem]

In order to solve the above-mentioned problem, the inventors of the present invention examined the cause of the above-mentioned problem in a resin film for a polarizing plate used for a polarizing plate having at least a polarizer layer containing iodine, and found that by including at least an iodine migration inhibitor, Setting the film thickness within a specific range suppresses the movement of polyiodine, thereby suppressing the decrease in adhesive force and the deterioration of contrast caused by heat generation of the semiconductor substrate, thereby achieving the present invention. That is, the above-mentioned problems of the present invention are solved by the following means.

1. A resin film for a polarizing plate, which is at least used for a polarizing plate with a polarizer layer containing iodine, characterized in that it contains at least a thermoplastic resin and an iodine migration inhibitor, and the film thickness is more than 1 μm And less than 15μm.

2. The resin film for polarizing plates according to item 1, wherein the iodine transfer inhibitor is metal oxide particles, and the thermal conductivity of the resin film for polarizing plates is in the range of 0.2~0.6W/m･K.

3. The resin film for polarizing plates as described in Item 2, wherein the ratio of the average primary particle size to the average secondary particle size of the aforementioned metal oxide particles satisfies the following formula (1); Formula (1): 20<average secondary particle size/average primary particle size<2000.

4. The resin film for polarizing plates according to item 1, wherein the iodine transfer inhibitor is a non-organic acid, and the δP (polar force) of the Hansen solubility parameter (HSP value) of the non-organic acid is 5 ~9MPa ^0.5 range.

5. The resin film for polarizing plates as described in item 4, wherein the value of the ratio of δD (dispersion force) to δP (polar force) of the aforementioned HSP value of the aforementioned non-organic acid satisfies the following formula (2); Formula (2): 2<δD (dispersion force)/δP (polar force)<4.

6. The resin film for polarizing plates as described in item 4 or item 5, wherein the aforementioned iodine transfer inhibitor further contains sulfate ions, and the content of the aforementioned sulfate ions is 1 with respect to the total mass of solid components of the resin film for polarizing plates Within the range of ~100 mass ppm.

7. The resin film for polarizing plates according to any one of items 1 to 6, wherein the thermoplastic resin is a cycloolefin resin.

8. A method for manufacturing a resin film for a polarizing plate, which is a method for manufacturing a resin film for a polarizing plate as described in any one of items 1 to 7, characterized in that it has: A step of coating a resin film with a release layer as a support and coating a solution containing a thermoplastic resin and an iodine movement inhibitor on the release layer.

9. A polarizing plate, which is a polarizing plate having an adhesive layer and a polarizer layer on a resin film, characterized in that: as the aforementioned resin film, a polarizing plate as described in any one of items 1 to 7 is provided Use resin film.

10. The polarizing plate as described in item 9, wherein the thickness of the aforementioned polarizer layer is within the range of 4 to 15 μm.

11. A display device comprising a polarizing plate, characterized in that: the polarizing plate described in item 9 or 10 is provided as the polarizing plate. [Effect of the invention]

By means of the above means of the present invention, it is possible to provide a resin film for a polarizing plate that can suppress a decrease in adhesive force and a deterioration in contrast due to heat generation of a semiconductor substrate when used in a polarizing plate in a display device, and further comprises the resin film for a polarizing plate. Film polarizers and display devices.

Although it is not clear about the display mechanism or operation mechanism of the effect of this invention, it guesses as follows.

A polarizer layer made of iodine-dyed polyvinyl alcohol (PVA) film (hereinafter also referred to as "PVA iodine-dyed polarizer layer" or simply "polarizer layer"). Specifically, after the PVA film is dyed with iodine , the film is stretched to align the iodine to obtain the polarizing function. In addition, usually, the polarizer layer is bonded to both sides of the protective layer (also referred to as "resin film for polarizing plate" in the present invention) through the adhesive layer.

When the polarizer layer is thinner, that is, when the PVA film is thinner, since it is easy to break during stretching, sufficient tension cannot be applied for stretching, and the alignment is likely to decrease. In addition, in order to achieve the same polarizing function as before, that is, to contain polyiodine (I ₃ ⁻ , I ₅ ⁻ ) in the same amount as conventionally, it is necessary to increase the content of polyiodine per unit volume.

However, the amount of polyiodine that can be adsorbed and aligned by the thin film is limited. If the amount of polyiodine adsorbed and aligned exceeds the limit, a part of polyiodine will not be adsorbed and will be in a state that is easily detached (easy to move). Therefore, the alignment property is lowered, and the polarizing function of the polarizer layer is lowered. In addition, the easily mobile polyiodine migrates from the PVA film into the protective layer, possibly deteriorating the performance of the protective layer.

In particular, in communication equipment compatible with 5G, compared with conventional equipment, the semiconductor substrate generates more heat and is in a higher temperature environment, so more iodine tends to move more actively due to heat energy. Therefore, it is preferable to keep polyiodine in the PVA film even in a higher temperature environment.

As a means of suppressing the movement of iodine, there are means of dissipating heat in the polarizer layer to reduce the heat energy absorbed by polyiodine, and generating charge repulsion with actively moving polyiodine to prevent movement into the protective layer. means.

In the present invention, by containing an iodine movement inhibitor capable of suppressing the movement of iodine in the protective layer by the above-mentioned means, it is possible to keep much iodine in the PVA film.

Moreover, the conventional iodine movement suppression technology is to reduce the impact of excess iodine on the protective layer by chemically reacting with excess iodine to generate reactants. This reactant is easy to precipitate out of the interface between the protective layer and the adhesive layer or the interface between the adhesive layer and the polarizer layer, resulting in reduced adhesive force.

However, the iodine movement inhibitor of the present invention can suppress the reduction of the polarizing function of the polarizing film due to the ability to keep more iodine in the PVA film; The adhesion of the protective layer is reduced. Therefore, when the resin film for polarizing plates of the present invention is used as a protective layer for a polarizing plate in a display device, it is possible to suppress a decrease in adhesive force and a decrease in contrast due to heat generation of a semiconductor substrate.

[Mode of Carrying Out the Invention]

The resin film for a polarizing plate of the present invention is a resin film for a polarizing plate used at least for a polarizing plate having a polarizer layer containing iodine, and is characterized in that it contains at least a thermoplastic resin and an iodine migration inhibitor, and has a film thickness of 1 μm or more and no up to 15 μm. This feature is common or corresponds to the technical feature of the following embodiments.

As an embodiment of the present invention, from the viewpoint of releasing heat in the polarizer layer, the aforementioned iodine transfer inhibitor is preferably metal oxide particles, and the thermal conductivity of the aforementioned resin film for polarizing plates is preferably 0.2 to 0.6 W/ Within the range of m･K.

Also, from the viewpoint of promoting heat dissipation by the metal oxide particles, the value of the ratio of the average primary particle size to the average secondary particle size of the metal oxide particles preferably satisfies the following formula (1). Formula (1): 20<average secondary particle size/average primary particle size<2000

From the viewpoint of repelling polyiodine with charge, the aforementioned iodine transfer inhibitor is preferably a non-organic acid, and the δP (polar force) of the Hansen solubility parameter (HSP value) of the aforementioned non-organic acid is preferably 5 to 9 MPa within the range of ^0.5 .

Also, from the viewpoint of promoting charge repulsion by the non-organic acid, the ratio of δD (dispersion force) to δP (polar force) of the HSP value of the non-organic acid preferably satisfies the following formula (2). Formula (2): 2<δD (dispersion force)/δP (polar force)<4

Furthermore, from the viewpoint of stable polarity of the non-organic acid, it is preferable that the aforementioned iodine transfer inhibitor further contains sulfate ions, and the content of the aforementioned sulfate ions is 1 to 100% with respect to the total mass of the solid content of the resin film for polarizing plates. Preferably within the range of mass ppm.

From the viewpoint of improving the water resistance of the polarizing plate, the thermoplastic resin is preferably a cycloolefin resin.

The method for producing a resin film for polarizing plates according to the present invention is characterized by comprising: using a resin film having a release layer as a support, and coating a solution containing a thermoplastic resin and an iodine migration inhibitor on the release layer.

The resin film for a polarizing plate of the present invention is preferably included in the polarizing plate of the present invention, and further preferably included in the display device of the present invention. Also, from the viewpoint of obtaining a thinner polarizing plate and a display device, the thickness of the aforementioned polarizing sublayer is preferably in the range of 4 to 15 μm.

Hereinafter, the present invention, its components, and forms and aspects for carrying out the present invention will be described. Also, in this case, "~" is used to mean including the values described before and after it as the lower limit value and the upper limit value. However, if there is a case of "exceeding" or "not reaching" before the numerical value, the numerical value is not included as the lower limit value and the upper limit value. For example, "1 to less than 15 μm" means "more than 1 μm and less than 15 μm" in detail.

≪1 The resin film for polarizing plates of the present invention≫ The resin film for a polarizing plate of the present invention is a resin film for a polarizing plate used at least for a polarizing plate having a polarizer layer containing iodine, and is characterized in that it contains at least a thermoplastic resin and an iodine migration inhibitor, and has a film thickness of 1 μm or more and no up to 15 μm.

The resin film for polarizing plates of the present invention can pass through the adhesive layer and be bonded to the polarizer layer to protect the polarizer layer. The polarizer can use a resin film to protect both sides of the polarizer layer, or use other known protective layers on one side.

When the thickness of the resin film for polarizing plates of this invention is less than 1 micrometer, sufficient strength as a protective layer cannot be acquired. Moreover, when it is 15 micrometers or more, a polarizing plate cannot be thinned, and the capacity of the battery mounted in a communication apparatus becomes insufficient.

[1.1 Thermoplastic resin] In the present invention, the term "thermoplastic resin" means a thermoplastic resin other than cellulose acylate resin. The resin used is not particularly limited as long as it is cellulose acylate resin, and examples include cycloolefin resin (COP), polycarbonate resin, (meth)acrylic resin, styrene-(methyl) Acrylate copolymer, fumaric acid diester resin, polyarylate resin, etc.

From the viewpoint of improving the water resistance of the polarizing plate, the moisture content of the thermoplastic resin of the present invention is preferably 3.0% or less. By setting the storage environment at 23°C and 55%RH, the moisture content can be adjusted within the above range. Moisture content can be measured by the following method.

About 1 g of the thermoplastic resin was prepared, and its absolute dry mass (WB) was measured. After immersing this sample in distilled water at 25°C (normal temperature) for 1 hour, measure the mass (WA) of the sample in which the water content is in an equilibrium state, and calculate the water content by the following formula. Equilibrium moisture content (mass%)={(WA-WB)/WA}×100

＜Cycloolefin resin＞ In the present invention, the cycloolefin-based resin is preferably a polymer of a cycloolefin monomer, or a copolymer of a cycloolefin monomer and other copolymerizable monomers.

The cycloolefin monomer is preferably a cycloolefin monomer having a norbornene skeleton, more preferably a cycloolefin monomer having a structure represented by the following general formula (A-1) or (A-2).

In the general formula (A-1), R ¹ to R ⁴ each independently represent a hydrogen atom, a hydrocarbon group with 1 to 30 carbon atoms, or a polar group; p is an integer of 0 to 2. However, all of R ¹ to R ⁴ do not simultaneously represent a hydrogen atom, R ¹ and R ² do not simultaneously represent a hydrogen atom, and R ³ and R ⁴ do not simultaneously represent a hydrogen atom.

In the general formula (A-1), the hydrocarbon group having 1 to 30 carbon atoms represented by R ¹ to R ⁴ is, for example, preferably a hydrocarbon group having 1 to 10 carbon atoms, more preferably a hydrocarbon group having 1 to 5 carbon atoms Hydrocarbyl. The hydrocarbon group having 1 to 30 carbon atoms may further have, for example, a linking group containing a halogen atom, an oxygen atom, a nitrogen atom, a sulfur atom or a silicon atom. Examples of such linking groups include divalent polar groups such as carbonyl groups, imino groups, ether bonds, silyl ether bonds, and thioether bonds. Examples of hydrocarbon groups having 1 to 30 carbon atoms include methyl, ethyl, propyl, and butyl groups.

In the general formula (A-1), examples of the polar groups represented by R ¹ to R ⁴ include carboxyl, hydroxyl, alkoxy, alkoxycarbonyl, aryloxycarbonyl, amine, amide and cyano. Among them, carboxyl group, hydroxyl group, alkoxycarbonyl group and aryloxycarbonyl group are preferable, and alkoxycarbonyl group and aryloxycarbonyl group are preferable from the viewpoint of ensuring solubility during film formation from a solution.

p in the general formula (A-1) is preferably 1 or 2 from the viewpoint of improving the heat resistance of the resin film for polarizing plates. This is because when p is 1 or 2, the resulting polymer becomes bulky and the glass transition temperature tends to rise. In addition, it can respond to humidity to some extent, and there is an advantage that it is easy to control the curl balance as a laminate.

In the general formula (A-2), R ⁵ represents a hydrogen atom, a hydrocarbon group with 1 to 5 carbons, or an alkylsilyl group with an alkyl group with 1 to 5 carbons; R ⁶ represents a carboxyl group, a hydroxyl group, an alkoxycarbonyl group, Aryloxycarbonyl group, amino group, amido group, cyano group or halogen atom (fluorine atom, chlorine atom, bromine atom or iodine atom); p represents an integer of 0~2.

R in the general formula (A-2) preferably represents a hydrocarbon group with 1 to ⁵ carbons, more preferably a hydrocarbon group with 1 to 3 carbons.

^R in the general formula (A-2) preferably represents a carboxyl group, a hydroxyl group, an alkoxycarbonyl group and an aryloxycarbonyl group, and is more preferably an alkoxycarbonyl group and Aryloxycarbonyl.

p in the general formula (A-2) preferably represents 1 or 2 from the viewpoint of improving the heat resistance of the resin film for polarizing plates. This is because when p represents 1 or 2, the resulting polymer becomes bulky and tends to raise the glass transition temperature.

A cycloolefin monomer having a structure represented by the general formula (A-2) is preferable from the viewpoint of improving solubility in organic solvents. Organic compounds generally reduce their crystallinity by disrupting their symmetry and increase their solubility in organic solvents. R ⁵ and R ⁶ in the general formula (A-2) are for the symmetry axis of the molecule, and are only substituted on one side of the ring to constitute a carbon atom, so the symmetry of the molecule is low, that is, it has the general formula (A-2) The cycloolefin monomer system with the structure shown has high solubility, and is suitable for producing a resin film for polarizing plates by solution casting.

In the polymer of the cycloolefin monomer, the content ratio of the cycloolefin monomer having the structure represented by the general formula (A-2) is preferably relative to the total of all the cycloolefin monomers constituting the cycloolefin resin. More than 70 mole%, more preferably more than 80 mole%, and more preferably 100 mole%. When the cycloolefin monomer having a structure represented by the general formula (A-2) is contained at a certain level or more, the alignment of the resin will increase, and thus the phase difference (retardation) value will easily increase.

Below, specific examples of cycloolefin monomers having a structure represented by general formula (A-1) are shown in exemplified compounds 1 to 14, and cyclic olefin monomers having a structure represented by general formula (A-2) are shown in exemplified compounds 15 to 34. A specific example of the cycloolefin monomer of the structure.

Examples of copolymerizable monomers capable of copolymerizing with cycloolefin monomers include copolymerizable monomers capable of ring-opening copolymerization with cycloolefin monomers and copolymerizable monomers capable of addition copolymerization with cycloolefin monomers. single sex etc.

Cycloalkenes such as cyclobutene, cyclopentene, cycloheptene, cyclooctene, and dicyclopentadiene are included in examples of the copolymerizable monomer capable of ring-opening copolymerization.

Examples of the addition-copolymerizable copolymerizable monomer include unsaturated double bond-containing compounds, vinyl-based cyclic hydrocarbon monomers, (meth)acrylates, and the like. Examples of compounds containing unsaturated double bonds include olefin-based compounds having 2 to 12 carbon atoms (preferably 2 to 8), and examples thereof include ethylene, propylene, and butene. Vinylcyclopentene-based monomers such as 4-vinylcyclopentene and 2-methyl-4-isopropenylcyclopentene are included in examples of vinyl-based cyclic hydrocarbon monomers. Among the examples of (meth)acrylates, those with 1 to 20 carbon atoms including methyl (meth)acrylate, 2-ethylhexyl (meth)acrylate and cyclohexyl (meth)acrylate, etc. Alkyl methacrylate.

The content ratio of the cycloolefin monomer in the copolymer of the cycloolefin monomer and the copolymerizable monomer is preferably in the range of 20 to 80 mole % relative to the total of all monomers constituting the copolymer, and more preferably Preferably in the range of 30~70 mole%.

The cycloolefin-based resin is as mentioned above, and the cycloolefin monomer having a norbornene skeleton, preferably a cycloolefin monomer having a structure represented by general formula (A-1) or (A-2), is polymerized or copolymerized. Examples of polymers obtained by polymerization include the following.

1) Ring-opening polymer of cycloolefin monomer 2) Ring-opening copolymer of cycloolefin monomer and its copolymerizable monomer capable of ring-opening copolymerization 3) The hydrogenated product of the ring-opening (co)polymer of the above 1) or 2) 4) A (co)polymer obtained by cyclizing the ring-opening (co)polymer of the above 1) or 2) by the Friedel-Crafts reaction and then hydrogenating it 5) Saturated copolymers of cycloolefin monomers and compounds containing unsaturated double bonds 6) Addition copolymers of cyclic olefin monomers and vinyl cyclic hydrocarbon monomers and their hydrogenated products 7) Alternating copolymer of cycloolefin monomer and (meth)acrylate The above-mentioned polymers of 1) to 7) can be obtained by well-known methods, such as the methods described in JP-A-2008-107534 or JP-A-2005-227606. For example, catalysts or solvents used in the ring-opening copolymerization of the above-mentioned 2), for example, those described in paragraphs 0019 to 0024 of JP-A-2008-107534 can be used. As the catalysts used for the hydrogenation of the above 3) and 6), for example, those described in paragraphs 0025 to 0028 of JP-A-2008-107534 can be used. As the acidic compound used in the Friedel-Kuft reaction of the above 4), for example, those described in paragraph 0029 of JP-A-2008-107534 can be used. As the catalyst used for the addition polymerization of the above 5) to 7), for example, those described in paragraphs 0058 to 0063 of JP-A-2005-227606 can be used. The alternating copolymerization reaction of the above 7) can be carried out, for example, by the method described in paragraphs 0071 and 0072 of JP-A-2005-227606.

Among them, the polymers of the above-mentioned 1) to 3) and 5) are preferred, and the polymers of the above-mentioned 3) and 5) are more preferred. That is, the cycloolefin-based resin is preferably composed of a structural unit represented by the following general formula (B-1) and At least one of the structural units represented by the following general formula (B-2), more preferably contains only the structural unit represented by the general formula (B-2), or contains the structure represented by the general formula (B-1) Both of the unit and the structural unit represented by the general formula (B-2). The structural unit represented by the general formula (B-1) is a structural unit derived from the cycloolefin monomer represented by the aforementioned general formula (A-1), and the structural unit represented by the general formula (B-2) is derived from the aforementioned A structural unit of a cycloolefin monomer represented by general formula (A-2).

In general formula (B-1), X represents -CH=CH- or -CH ₂ CH ₂ -; R ¹ to R ⁴ and p are each synonymous with R ¹ to R ⁴ and p in general formula (A-1).

In general formula (B-2), X represents -CH=CH- or -CH ₂ CH ₂ -; R ⁵ to R ⁶ and p are each synonymous with R ⁵ to R ⁶ and p in general formula (A-2).

The cycloolefin-based resin used in the present invention may be a commercially available product. Examples of commercially available cycloolefin-based resins include Atong (registered trademark) G (eg, G7810, etc.), Atong F, and Atong R (eg, R4500, R4900, R5000, etc.) manufactured by JSR Co., Ltd. ) and Atong RX (for example, RX4500, etc.).

The intrinsic viscosity [η]inh of cycloolefin resin is measured at 30°C, preferably in the range of 0.2~5cm ³ /g, more preferably in the range of 0.3~3cm ³ /g, especially preferably in the range of 0.4~ Within the range of 1.5cm ³ /g.

The number average molecular weight (Mn) of the cycloolefin resin is preferably in the range of 8,000 to 100,000, more preferably in the range of 10,000 to 80,000, and most preferably in the range of 12,000 to 50,000. The weight average molecular weight (Mw) of the cycloolefin resin is preferably within the range of 20,000 to 300,000, more preferably within the range of 30,000 to 250,000, and most preferably within the range of 40,000 to 200,000. The number average molecular weight or weight average molecular weight of a cycloolefin resin can be measured in terms of polystyrene by gel permeation chromatography (GPC).

＜Gel Permeation Chromatography＞ Solvent: dichloromethane String: Shodex K806, K805, K803G (manufactured by Showa Denko Co., Ltd., used for connecting 3 strings) Column temperature: 25°C Sample concentration: 0.1% by mass Detector: RI Model 504 (manufactured by GL Science Co., Ltd.) Pump: L6000 (manufactured by Hitachi, Ltd.) Flow: 1.0mL/min Calibration curve: Calibration curve of 13 samples using standard polystyrene STK standard polystyrene (manufactured by Tosoh Co., Ltd.) Mw=500~2,800,000. The 13 samples are preferably used approximately equally spaced.

When the intrinsic viscosity [η]inh, the number average molecular weight and the weight average molecular weight are within the above ranges, the heat resistance, water resistance, chemical resistance, mechanical properties and molding processability of the resin film for polarizing plates of the cycloolefin-based resin are changed. good.

The glass transition temperature (Tg) of the cycloolefin resin is usually above 110°C, preferably in the range of 110-350°C, more preferably in the range of 120-250°C, and most preferably in the range of 120-220°C. When Tg is 110 degreeC or more, it becomes easy to suppress deformation|transformation under high temperature conditions. On the other hand, when Tg is 350 degrees C or less, molding processing becomes easy, and the deterioration of resin by heat at the time of molding processing is also suppressed easily.

The content of the cycloolefin-based resin is preferably at least 70% by mass, more preferably at least 80% by mass, based on the total mass of the resin film for polarizing plates.

＜Polycarbonate resin＞ In the present invention, the polycarbonate-based resin is not particularly limited, but from the viewpoint of chemical properties and physical properties, an aromatic polycarbonate resin is preferred, and a bisphenol A-based polycarbonate resin is particularly preferred. Among them, it is more preferable to use a bisphenol A derivative in which a benzene ring, a cyclohexane ring, an aliphatic hydrocarbon group, and the like are introduced into bisphenol A. Furthermore, it is particularly preferable to use a polycarbonate-based resin having a structure in which the anisotropy per unit molecule is reduced by introducing a derivative of the above-mentioned functional group asymmetrically to the central carbon of bisphenol A. As such a polycarbonate resin, for example, it is particularly preferable to use one in which two methyl groups at the central carbon of bisphenol A are replaced with benzene rings, and one hydrogen of each benzene ring of bisphenol A is replaced with a methyl group or a benzene ring. Groups, etc., the central carbon is substituted into asymmetric ones, and the polycarbonate resin is obtained.

Specifically, those obtained from 4,4'-dihydroxydiphenylalkane or its halogen substitutes by phosgene method or transesterification method, for example, 4,4'-dihydroxydiphenyl Phenylmethane, 4,4'-dihydroxydiphenylethane, 4,4'-dihydroxydiphenylbutane, etc. In addition, for example, JP-A 2006-215465, JP-A 2006-91836, JP-A 2005-121813, JP-A 2003-167121, JP-A 2009-126128 Polycarbonate-based resins described in Japanese Patent Publication No. 2012-31369, Japanese Patent Application Laid-Open No. 2012-67300, International Publication No. 00/26705, and the like.

Polycarbonate-based resins can also be mixed with transparent resins such as polystyrene-based resins, methyl methacrylate-based resins, and cellulose acetate-based resins. In addition, a resin layer containing a polycarbonate-based resin may be laminated on at least one surface of a resin film formed using a cellulose acetate-based resin.

The polycarbonate resin preferably has a glass transition temperature (Tg) of 110°C or higher and a moisture content (measured in water at 23°C for 24 hours) of 0.3% or less. Also, more preferably, it has a Tg of 120°C or higher and a moisture content of 0.2% or lower.

＜(Meth)acrylic resin＞ In the present invention, the (meth)acrylic resin preferably includes at least a structural unit (U1) derived from methyl methacrylate and a structural unit (U2) derived from phenylmaleimide. The (meth)acrylic resin containing the structural unit (U2) derived from phenylmaleimide reduces the photoelastic coefficient of the resin film for polarizing plates and is also advantageous in that it is less likely to cause unevenness even when it absorbs moisture. point.

The (meth)acrylic resin may further contain other structural units other than the above. Examples of such other structural units include alkyl (meth)acrylates such as adamantyl acrylate, cycloalkyl (meth)acrylates such as 2-ethylhexyl acrylate, and the like. Among them, it is preferable to further include a structural unit (U3) derived from an alkyl acrylate from the viewpoint of reducing the deterioration in brittleness due to the inclusion of the structural unit (U2) derived from phenylmaleimide.

That is, the (meth)acrylic resin preferably comprises a structural unit (U1) derived from methyl methacrylate, a structural unit (U2) derived from phenylmaleimide, and a structural unit derived from alkyl acrylate. Structural unit (U3).

The content of the structural unit (U1) derived from methyl methacrylate is preferably in the range of 50 to 95% by mass, more preferably 70 to 90% by mass, based on all the structural units constituting the (meth)acrylic resin % range.

Since the structural unit (U2) derived from phenylmaleimide has a relatively rigid structure, it can improve the mechanical strength of the resin film for polarizing plates. Also, the structural unit (U2) derived from phenylmaleimide has a relatively bulky structure due to the presence of microvoids in the resin matrix through which rubber particles can move. Therefore, the rubber particles can be biased in the surface layer of the resin film for polarizing plates.

The content of the structural unit (U2) derived from phenylmaleimide is preferably in the range of 1 to 25 mass % with respect to all the structural units constituting the (meth)acrylic resin. When the content of the structural unit (U2) derived from phenylmaleimide is 1% by mass or more, the resin film for polarizing plates has excellent storage properties in a high-humidity environment. By 25 mass % or less, the brittleness of the resin film for polarizing plates is hard to be impaired excessively. The content of the structural unit (U2) derived from phenylmaleimide is more preferably within the range of 7 to 15% by mass from the above viewpoint.

Since the alkyl acrylate-derived structural unit (U3) can impart moderate flexibility to the resin, for example, brittleness due to the inclusion of the phenylmaleimide-derived structural unit (U2) can be improved.

The alkyl acrylate preferably has an alkyl moiety with 1-7 carbon atoms, preferably an alkyl acrylate with 1-5 carbon atoms. Examples of alkyl acrylate include methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, 2-hydroxyethyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, and the like.

The content of the structural unit (U3) derived from an alkyl acrylate is preferably within the range of 1 to 25 mass % with respect to all the structural units constituting the (meth)acrylic resin. When the content of the structural unit (U3) derived from the alkyl acrylate is 1% by mass or more, moderate flexibility can be imparted to the (meth)acrylic resin, and the resin film for polarizing plates is not too brittle and difficult to break. Moreover, when it is 25 mass % or less, Tg of the resin film for polarizing plates is not too low, and the preservability in the high-humidity environment of the resin film for polarizing plates is excellent. The content of the structural unit (U3) derived from an alkyl acrylate is more preferably within the range of 5 to 15% by mass from the above viewpoint.

Ratio of phenylmaleimide-derived structural unit (U2) to the total amount of phenylmaleimide-derived structural unit (U2) and alkyl acrylate-derived structural unit (U3) Preferably it is within the range of 20 to 70% by mass. When this ratio is 20 mass % or more, it becomes easy to raise the tensile elastic modulus G2 of the resin film for polarizing plates, and when it is 70 mass % or less, the resin film for polarizing plates is not too brittle.

The glass transition temperature (Tg) of (meth)acrylic resin becomes like this. Preferably it is 100 degreeC or more, More preferably, it exists in the range of 120-150 degreeC. When Tg of a (meth)acryl-type resin exists in the said range, it becomes easy to improve the heat resistance of the resin film for polarizing plates. In order to adjust the Tg of the (meth)acrylic resin, for example, it is preferable to adjust the content of the structural unit (U2) derived from a phenylmaleimide or the structural unit (U3) derived from an alkyl acrylate.

The weight average molecular weight (Mw) of the (meth)acrylic resin is not particularly limited, and can be adjusted according to the purpose. The weight-average molecular weight of the (meth)acrylic resin, for example, promotes the entanglement of resin molecules to improve the toughness of the resin film for polarizing plates, and is not easy to break, or in the view of moderately increasing the coefficient of humidity expansion (also known as "" CHE ratio"), from the viewpoint of easily adjusting the amount of curl to a better degree of adhesion, is preferably 100,000 or more, more preferably 1 million or more. When the weight average molecular weight of the (meth)acrylic resin is 1 million or more, the toughness of the obtained resin film for polarizing plates can be improved. Thereby, when this resin film for polarizing plates is conveyed to a laminated film, it can suppress that the resin film for polarizing plates breaks by conveying tension, and can improve conveyance stability. From the same viewpoint, the weight average molecular weight of the (meth)acrylic resin is more preferably in the range of 1.5 million to 3 million. The method for measuring the weight average molecular weight is as described above.

＜Styrene-(meth)acrylate copolymer＞ In this invention, the resin film for polarizing plates excellent in transparency is obtained by using a styrene-(meth)acrylate copolymer (it is also called a styrene-acrylic resin hereafter). Moreover, since the humidity expansion coefficient can be adjusted by the copolymerization ratio of a styrene part, curling of the polarizing plate of this invention can be controlled by changing these ratios.

The styrene-acrylic resin is formed by addition-polymerizing at least a styrene monomer and a (meth)acrylate monomer. In addition to styrene represented by the structural formula of CH ₂ ═CH—C ₆ H ₅ , the styrene monomer system also includes styrene derivatives having well-known side chains or functional groups in the styrene structure.

In addition, the (meth)acrylate monomer system except CH(R ₁ )=CHCOOR ₂ (R ₁ represents a hydrogen atom or a methyl group, and R ² represents an alkyl group with 1 to 24 carbons) or methacrylate In addition to acrylates, acrylate derivatives or methacrylate derivatives having well-known side chains or functional groups in the structure of these esters are also included.

Examples of styrene monomers include styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-phenylstyrene, p -Ethylstyrene, 2,4-dimethylstyrene, p-tert-butylstyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p-n-decylbenzene Ethylene and p-n-dodecylstyrene.

Examples of (meth)acrylate monomers include methyl acrylate, ethyl acrylate, isopropyl acrylate, n-butyl acrylate, tert-butyl acrylate, isobutyl acrylate, n-octyl acrylate, acrylic acid Acrylate monomers such as 2-ethylhexyl (2EHA), octadecyl acrylate, lauryl acrylate and phenyl acrylate; methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, methyl Isopropyl acrylate, isobutyl methacrylate, tert-butyl methacrylate, n-octyl methacrylate, 2-ethylhexyl methacrylate, octadecyl methacrylate, lauryl methacrylate, Methacrylates such as phenyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate.

Furthermore, in this specification, the so-called "(meth)acrylate monomer" is a general term for "acrylate monomer" and "methacrylate monomer", and means one or both of them. For example, "methyl (meth)acrylate" means either or both of "methyl acrylate" and "methyl methacrylate".

The above (meth)acrylate monomers may be used alone or in combination of two or more. For example, any of the following may be used: a copolymer is formed by using a styrene monomer and two or more kinds of acrylate monomers, a copolymer is formed by using a styrene monomer and two or more kinds of methacrylate monomers, And styrene monomers are used in combination with acrylate monomers and methacrylate monomers to form copolymers.

The weight average molecular weight (Mw) of the styrene-acrylic resin is preferably within a range of 5,000 to 150,000, more preferably within a range of 30,000 to 120,000, from the viewpoint of easy control of plasticity.

The styrene-acrylic resin used in the present invention may be a commercial item, and MS resin "TX320XL" manufactured by Denka Co., Ltd. is mentioned as an example.

＜Fumaric acid diester resin＞ In the present invention, the fumaric acid diester resin is a fumaric acid diester resin comprising a fumaric acid diester residue unit and a fumaric acid diester residue unit having an alkyl group having 1 or 2 carbon atoms. .

Here, the alkyl groups having 1 or 2 carbon atoms in the fumaric acid diester residue unit having an alkyl group having 1 or 2 carbon atoms are each independently, and examples thereof include methyl groups, ethyl groups, and the like. In addition, these may be substituted with halogen groups such as fluorine and chlorine, ether groups, ester groups, or amino groups. Examples of the fumaric acid diester residue unit having an alkyl group having 1 or 2 carbon atoms include a fumarate dimethyl residue unit and a fumarate diethyl residue unit. Moreover, these may contain 1 type or 2 or more types.

Specific examples of fumaric acid diester resins include diisopropyl fumarate/dimethyl fumarate copolymer resin, diisopropyl fumarate/diethyl fumarate copolymer resin wait.

Fumaric acid diester resins may also contain other monomer residue units as long as they do not exceed the scope of the present invention. As other monomer residue units, for example, styrene residue units, α- Styrenic residue units such as methylstyrene residue units; (meth)acrylic acid residue units; methyl (meth)acrylate residue units, ethyl (meth)acrylate residue units, (meth)acrylate residue units, (meth)acrylate residue units such as butyl acrylate residue units; vinyl ester residue units such as vinyl acetate residue units and vinyl propionate residue units; acrylonitrile residue units; Acrylonitrile residue unit; vinyl ether residue unit such as methyl vinyl ether residue unit, ethyl vinyl ether residue unit, butyl vinyl ether residue unit, etc.; N-methylmaleinyl N-substituted maleimide residue units such as amine residue unit, N-cyclohexylmaleimide residue unit, N-phenylmaleimide residue unit, etc.; ethylene residue unit, Olefin residue units such as propylene residue units; di-n-butyl fumarate residue units, bis(2-ethylhexyl) fumarate residue units, etc. other than the aforementioned fumaric acid diester residue units Fumaric acid diester residues; and 1 or more selected cinnamic acid and cinnamic acid ester units.

The blending ratio of the fumaric acid diester resin used in the present invention is preferably 50-99 mol% of diisopropyl fumarate residue units and fumaric acid diisopropyl fumarate having an alkyl group with 1 or 2 carbon atoms. Ester residue unit 1~50 mol%. From the point of view of retardation characteristics or strength when it becomes a retardation film, it is particularly preferable to be a fumarate having 60 to 95 mol% of diisopropyl fumarate residue units and an alkyl group with 1 or 2 carbons. Fumaric acid diester resin composed of 5~40 mol% of acid diester residue units.

The fumaric acid diester resin used in the present invention is preferably in the range of 50,000 to 250,000 in standard polystyrene conversion number average molecular weight obtained from the elution curve measured by the aforementioned gel permeation chromatography.

(Synthesis example of fumaric acid diester resin) In a 1L autoclave equipped with a stirrer, a cooling pipe, a nitrogen introduction pipe, and a thermometer, 2 g of hydroxypropyl methylcellulose (manufactured by Shin-Etsu Chemical Co., Ltd., trade name Metolose 60SH-50), 600 g of distilled water, and diisofumaric acid were added. 330 g of propyl ester, 70 g of diethyl fumarate, and 3 g of tertiary butylperoxypivalate as a polymerization initiator were bubbled with nitrogen for 1 hour, and kept at 50° C. while stirring at 400 rpm. Free radical suspension polymerization was carried out for 24 hours. After cooling to room temperature, the suspension containing the generated polymer particles was separated by filtration, and washed with distilled water and methanol to obtain a fumaric acid diester resin (yield: 75%).

The number average molecular weight of the obtained fumaric acid diester resin was 120,000. Also, by 1H-NMR measurement, it was confirmed that the resin composition was diisopropyl fumarate residue unit/diethyl fumarate residue unit=84/16 (mol %).

＜Polyarylate resin＞ In the present invention, a film excellent in toughness can be obtained by using a polyarylate-based resin. This polyarylate resin contains at least a structural unit derived from an aromatic diol and a structural unit derived from an aromatic dicarboxylic acid.

The polyarylate-based resin used in the present invention may be a commercially available product, and PAR resin "U-100" manufactured by UNITIKA Co., Ltd., with a weight average molecular weight (Mw) of 100,000, is mentioned as an example.

[1.2 Iodine movement inhibitors] In the present invention, the so-called "iodine movement inhibitor" refers to a chemical material having the function of physically inhibiting the movement of iodine, including heat-dissipating materials and charge-repelling materials. The so-called heat-dissipating material refers to a material that actively moves in order to suppress the absorption of heat energy by polyiodine, and is easy to dissipate the heat in the polarizer layer. In addition, the so-called charge-repelling material refers to a material that prevents the movement of iodine by generating charge repulsion with respect to polyiodine having a charge.

[1.2.1 Heat dissipation material] The heat dissipation material is not particularly limited as long as it has relatively high thermal conductivity and can improve the thermal conductivity of the resin film for polarizing plates of the present invention. Examples include polymethyl methacrylate (PMMA), polycarbonate, glass, silicone rubber, diamond, diamond-like carbon (DLC), aluminum nitride, silicon nitride, boron nitride, magnesium nitride, Silicon carbide, aluminum oxide, silicon oxide, zinc oxide, magnesium oxide, etc. Among these, metal oxide particles are preferable from the viewpoint of thermal conductivity. Moreover, it is preferable to use transparent particle|grains from a viewpoint which does not impair the transparency of the resin film for polarizing plates.

The thermal conductivity of the resin film for polarizing plates containing the above heat-dissipating material as an iodine transfer inhibitor is preferably in the range of 0.2 to 0.6 W/m･K. Within the above range, in a display device provided with a polarizing plate having the polarizing plate resin film of the present invention, even if the polarizer layer generates heat during use, or heat is transmitted to the polarizer layer due to heat generated by the semiconductor substrate, Since the thermal conductivity of the resin film for polarizing plates is relatively high, that is, the resin film for polarizing plates has heat dissipation, heat is not easily transmitted to polyiodine, and the movement of polyiodine due to heat can be suppressed. Furthermore, when the thermal conductivity is 0.2W/m･K or more, the resin film for polarizing plates has sufficient heat dissipation, and when it is less than 0.6W/m･K, it is difficult to cause display problems caused by temperature differences with other components. Defective condition of the device.

The thermal conductivity of the resin film of the present invention can be measured as follows. The resin film was sandwiched between a TO-3 type heater case and a copper plate, and the thickness of the film was compressed by 10%. Next, 5W of electric power was applied to the copper heating box and kept for 4 minutes, and the temperature difference between the copper heating box and the copper plate was measured. Thermal conductivity can be calculated by the following formula. Thermal conductivity {W/m･K}={power (W)×thickness (m)}/{temperature difference (K)×measurement area (m ² )}

[1.2.1.1 Metal oxide particles] In the present invention, the heat dissipation material is preferably metal oxide particles from the viewpoint of easily adjusting the thermal conductivity of the resin film for polarizing plates to the above-mentioned suitable range. Examples of metal oxide particles include aluminum oxide, silicon oxide, zinc oxide, magnesium oxide, titanium oxide, and the like. These can be surface treated with silane coupling agents, etc.

As the metal oxide particles used in the present invention, commercially available products can be used, and examples of commercially available alumina products include trade name "AS-50" (manufactured by Showa Denko Co., Ltd.), trade name "AL-13KT" ( Average particle diameter: 96 μm) (manufactured by Showa Denko Co., Ltd.) and the like. Moreover, as a commercial item of zinc oxide, a brand name "SnO-310" (made by Sumitomo Osaka Cement Co., Ltd.), a brand name "SnO-350" (manufactured by Sumitomo Osaka Cement Co., Ltd.), and a brand name "SnO-410" are mentioned. (manufactured by Sumitomo Osaka Cement Co., Ltd.), etc.

In the present invention, the term "primary particle" is used as a general term for crystals and crystals that share a specific surface to form a strong aggregate (called "aggregate"). Furthermore, the particle aggregate (referred to as "agglomerate") formed by the aggregation of the primary particles is called "secondary particle".

In the present invention, the average primary particle diameter (particle diameter of the above-mentioned primary particles) and the average secondary particle diameter (particle diameter of the above-mentioned secondary particles) are defined as follows.

In the sample prepared by the ultrathin section method, observe the primary particle (or secondary particle) with a transmission electron microscope (for example, H-7100FA manufactured by Hitachi), and assume the diameter of a circle equal to its projected area (The so-called circle equivalent diameter) is regarded as the primary particle diameter (or secondary particle diameter). Then, the particle diameters of 1000 primary particles (or secondary particles) obtained in this way were averaged, and the average value was regarded as the average primary particle diameter (or average secondary particle diameter).

The average primary particle size of the metal oxide particles is preferably in the range of 50-100 nm, more preferably about 80 nm. Also, the average secondary particle diameter is preferably at least 1000 nm, more preferably at least 1200 nm. Furthermore, the shape of the particles may be spherical or needle-like.

The value of the ratio of the average primary particle size to the average secondary particle size of the metal oxide particles preferably satisfies the following formula. 20<average secondary particle size/average primary particle size<2000

The metal oxide particles of the present invention realize the heat dissipation function by absorbing the heat energy of the polarizer layer and transferring the heat energy to adjacent particles. In the resin film for polarizing plates of the present invention, the metal oxide particles are separated by the thermoplastic resin with relatively low thermal conductivity, so it is difficult to transmit heat energy. Therefore, due to the moderate formation of aggregates of the metal oxide particles, the particles are in contact with each other, so that heat energy can be transmitted more, and the heat dissipation function is improved.

When the ratio of the average primary particle size to the average secondary particle size of the metal oxide particles exceeds 20, a sufficient heat dissipation function is obtained. The larger the ratio, the better, but if it is less than 2000, the temperature difference between the various components in the display device will not be too large, and the deterioration and failure of the display device can be prevented. The value of the ratio of the average primary particle diameter to the average secondary particle diameter of the metal oxide particles can be controlled by dispersing the metal oxide particles.

Relative to the total mass of the thermoplastic resin, the content of the heat dissipation material is preferably in the range of 5-50% by mass. With 5% by mass or more, sufficient thermal conductivity is obtained, and with 50% by mass or less, sufficient strength is obtained in terms of productivity.

[1.2.2 Charge-repelling material] The charge-repelling material is not particularly limited as long as it prevents the movement of iodine by generating charge repulsion with respect to polyiodine having a charge. From the viewpoint of charge repulsion with polyiodine (I ₃ ^- or I ₅ ^- ), such a charge repelling material is preferably a compound having a negative charge or a compound having a negative polarity.

[1.2.2.1 Non-organic acids] In the present invention, the charge-repelling material is preferably a non-organic acid from the viewpoint that the reaction product is less likely to be precipitated by neutralization with polyiodine. In the present invention, the so-called non-organic acid refers to an organic compound having 5 or more carbon atoms that does not have a proton-donating group such as a carboxylic acid group or a sulfonic acid group. From the viewpoint of low reactivity and stability even in the presence of charge bias, an organic compound having 15 or more carbon atoms is more preferable. The polar non-organic acid is not particularly limited, and examples thereof include anionic surfactants, anionic ligands, triphenylmethane derivatives, barbituric acid-based compounds, and the like.

The molecular weight of the non-organic acid is preferably within the range of 200-1000, more preferably within the range of 250-800, and especially preferably within the range of 280-600. When the molecular weight is 200 or more, it is possible to suppress the disappearance of the non-organic acid due to volatilization during film formation of the resin film for polarizing plates. Moreover, when it is 1000 or less, the compatibility of the thermoplastic resin contained in a film and a non-organic acid becomes favorable, and the film with low haze is obtained.

The δP (polar force) of the Hansen solubility parameter (HSP value) of the non-organic acid is preferably within the range of 5~9MPa ^0.5 . When δP is 5 MPa ^0.5 or more, the charge repulsion between the non-organic acid system and polyiodine is sufficient. When δP is 9MPa ^0.5 or less, it has affinity with resin and suppresses bleeding. Also, by setting an appropriate repulsion force, the alignment of polyiodine in the polarizer layer can be maintained. The details of the Hansen solubility parameter system will be described later.

＜Anionic Surfactants＞ The anionic surfactant is not particularly limited, but is preferably a surfactant having a long-chain alkyl group, more preferably a surfactant having an alkyl group having 6 to 20 carbon atoms.

As examples, in the sulfate ester salt type, sodium lauryl sulfate, sodium hexyl sulfate, sodium heptyl sulfate, sodium octyl sulfate, sodium nonyl sulfate, sodium decyl sulfate, sodium lauryl sulfate, sodium tetradecyl sulfate, Sodium hexadecyl sulfate, sodium cetyl sulfate, sodium octadecyl sulfate, sodium eicosyl sulfate, or alkyl sulfate ester salts of potassium salts, calcium salts, ammonium salts, sodium polyoxyethylene hexyl ether sulfate, Sodium polyoxyethylene heptyl ether sulfate, sodium polyoxyethylene octyl ether sulfate, sodium polyoxyethylene nonyl ether sulfate, sodium polyoxyethylene decyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, polyoxyethylene tenyl ether sulfate Sodium tetrayl ether sulfate, sodium polyoxyethylene hexadecyl ether sulfate, sodium polyoxyethylene stearyl ether sulfate, sodium polyoxyethylene eicosyl ether sulfate, or polyoxyethylene of these potassium salts, ammonium salts, etc. Alkyl ether sulfate, sodium polyoxyethylene hexylphenyl ether sulfate, sodium polyoxyethylene heptylphenyl ether sulfate, sodium polyoxyethylene octylphenyl ether sulfate, sodium polyoxyethylene nonylphenyl ether sulfate, polyoxyethylene Sodium Oxyethylene Decyl Phenyl Ether Sulfate, Sodium Polyoxyethylene Lauryl Phenyl Ether Sulfate, Sodium Polyoxyethylene Tetradecyl Phenyl Ether Sulfate, Sodium Polyoxyethylene Hexadecyl Phenyl Ether Sulfate, Polyoxyethylene Decyl Phenyl Ether Sodium octalphenyl ether sulfate, sodium polyoxyethylene eicosylphenyl ether sulfate, or polyoxyethylene alkylphenyl ether sulfate, sodium caproate ethanolamide sulfate, potassium salt, ammonium salt, etc. Sodium ethanolamide caprylate sulfate, sodium ethanolamide caprate sulfate, sodium ethanolamide sulfate laurate, sodium ethanolamide sulfate palmitate, sodium ethanolamide sulfate stearate, sodium ethanolamide oleate sulfate or others Potassium salts, and other higher fatty acid alkanolamide sulfates, sulfated oils, higher alcohol ethoxysulfates, monoglycerol sulfates ( monoglysulfate) and so on.

In addition, in addition to the above-mentioned sulfate ester salt type, fatty acid soaps such as sodium oleate and castor oil potassium soap, N-acyl amino acids and their salts, polyoxyethylene alkyl carboxylates, acyl Carboxylate salt type of chemical peptides, sodium hexylsulfonate, sodium heptylsulfonate, sodium octylsulfonate, sodium nonylsulfonate, sodium decylsulfonate, sodium dodecylsulfonate, tetradecylsulfonate Sodium cetyl sulfonate, sodium cetyl sulfonate, sodium octadecyl sulfonate, a mixture of sodium aliphatic alkyl sulfonates with 6 to 18 carbon atoms, alkyl benzene sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonic acid Salt formalin polycondensate, salt formalin condensate of melamine sulfonic acid, dialkyl sulfosuccinate salt, alkenyl succinate, sulfosuccinic acid alkyl di-salt, polyoxyethylene alkyl sulfo Succinic acid disalt, alkyl sulfoacetate, α-olefin sulfonate, N-acylmethyl taurate, dimethyl-5-sulfoisophthalic acid sodium salt, etc. Oxyethylene alkyl ether phosphate, polyoxyethylene alkyl phenyl ether phosphate, phosphate ester salt type of alkyl phosphate, etc.

As an anionic surfactant, a commercial item can be used, For example, Elecut (registered trademark) S-412-2 by Takemoto Oil Co., Ltd., Electrostripper (registered trademark) F by Kao Corporation, etc. are mentioned.

＜Anionic ligand＞ The anionic ligand in the present invention refers to a divalent transition metal ion (for example, cobalt (II), nickel (II), copper (II), iron (II), zinc (II), etc.) Anionic ligands that form complexes.

As anionic ligands, compounds represented by the following general formulas (L1) to (L3) can be preferably used. However, in any compound, the carbon number is 5 or more.

In the formula, R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and X ₁ represents -NR ₅ R ₆ , OR ₇ , SR ₈ (R ₅ , R ₆ , R ₇ and R ₈ each represent a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group). n represents 0 or 1. In addition, R ₁ and R ₃ may be directly bonded to form a double bond, and two of R ₁ , R ₂ , R ₃ , R ₄ , and X ₁ may form a ring.

Examples of the alkyl group represented by R ₁ to R ₄ include methyl, ethyl, i-propyl, t-butyl, dodecyl, 1-hexylnonyl, etc., and examples of the cycloalkyl group include Cyclopropyl, cyclohexyl, bicyclo[2.2.1]heptyl, adamantyl, etc. Examples of the aryl group include phenyl, o-tolyl, o-anisyl, 1-naphthyl, and 9-anthracene Base etc.

These alkyl groups, cycloalkyl groups, and aryl groups may have a substituent. Examples of such substituents include linear or branched alkyl groups (methyl, ethyl, i-propyl, t-butyl, dodecyl, 1-hexylnonyl, etc.), cycloalkyl groups (cyclopropyl base, cyclohexyl, bicyclo[2.2.1]heptyl, adamantyl, etc.), alkenyl (2-propene, oleyl, etc.), aryl (phenyl, o-tolyl, o-anisyl, 1- Naphthyl, 9-anthryl, etc.), heterocyclic group (2-tetrahydrofuryl, 2-thienyl, 4-imidazolyl, 2-pyridyl, etc.), halogen atom (fluorine, chlorine, bromine, etc.), cyano, Nitro, alkylcarbonyl (acetyl, trimethylacetyl, etc.), arylcarbonyl (benzoyl, pentafluorobenzoyl, 3,5-di-tert-butyl-4-hydroxybenzene Formyl, etc.), oxycarbonyl (alkoxycarbonyl such as methoxycarbonyl, cyclohexyloxycarbonyl, dodecyloxycarbonyl, phenoxycarbonyl, 2,4-di-tert-pentylphenoxy Carbonyl, aryloxycarbonyl such as 1-naphthyloxycarbonyl), heterooxycarbonyl (2-pyridyloxycarbonyl, 1-phenylpyrazolyl-5-oxycarbonyl, etc.), carbamoyl ( Alkylaminoformyl such as dimethylaminoformyl, 4-(2,4-di-tert-pentylphenoxy)butylaminocarbonyl, phenylaminoformyl, 1-naphthylamine Arylamino formyl, such as formyl), alkoxy (methoxy, 2-ethoxyethoxy, etc.), aryloxy (phenoxy, 2,4-di-tert-pentylbenzene Oxy, 4-(4-hydroxyphenylsulfonyl)phenoxy, etc.), Heteroepoxy (4-pyridyloxy, 2-hexahydropyranyloxy, etc.), Carbonyloxy (acetyloxy Alkylcarbonyloxy groups such as trifluoroacetyloxy and trimethylacetyloxy groups, aryloxy groups such as benzoyloxy groups and pentafluorobenzoyloxy groups, etc.), carbamates Alkyl carbamate groups such as N,N-dimethyl carbamate, N-phenyl carbamate, N-(p-cyanophenyl) carbamate aryl carbamate group), sulfonyloxy (methanesulfonyloxy, trifluoromethanesulfonyloxy, dodecylsulfonyloxy and other alkylsulfonyloxy, benzenesulfonyloxy) Oxygen group, arylsulfonyloxy group such as p-toluenesulfonyloxy group), amino group (alkylamino group such as dimethylamino group, cyclohexylamine group, dodecylamine group, aniline group, p -Arylamino group such as tertiary octylanilino group), sulfonylamino group (alkylsulfonylamino group such as methanesulfonylamino group, heptafluoropropanesulfonylamino group, hexadecylsulfonylamino group, etc. Amine, p-toluenesulfonylamine, arylsulfonylamine of pentafluorobenzenesulfonylamine), sulfamoylamine (N,N-dimethylsulfamoylamine Alkylaminosulfonylamino groups such as N-phenylaminosulfonylamino groups, arylaminosulfonylamino groups such as N-phenylaminosulfonylamino groups), acylamino groups (acetylamino groups, myristylamino groups, etc.) Alkylcarbonylamine groups such as benzoylamine groups, arylcarbonylamino groups such as benzoylamino groups), ureido groups (alkylureido groups such as N,N-dimethylaminoureido groups, N-phenylureido groups, N-(p-cyanophenyl) ureido (aryl ureido, etc.), sulfonyl (methanesulfonyl, trifluoromethanesulfonyl, etc., alkylsulfonyl, p-toluenesulfonyl, etc. arylsulfonyl), sulfamoyl (dimethylsulfamoyl, 4-(2,4-di-tert-pentylphenoxy) butylaminosulfonyl, etc. Acyl group, arylsulfamoyl group such as phenylsulfamoyl group), alkylthio group (methylthio group, t-octylthio group, etc.), arylthio group (phenylthio group, etc.), heterocyclic thio group ( 1-phenyltetrazol-5-thio, 5-methylthio-1,3,4-oxadiazol-2-thio, etc.), etc.

In the formula, R ₉ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group, a thioether group or an amine group, and X ₂ and X ₃ represent -NR ₁₀ -, -O-, -S- or -CR ₁₁ (R ₁₂ )-(R ₁₀ , R ₁₁ and R ₁₂ each represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group, an aryloxy group or an amino group), and B represents Oxygen or sulfur atom. Also, R ₉ and X ₂ , R ₉ and X ₃ , or X ₂ and X ₃ may form a ring.

The alkyl, cycloalkyl, aryl, alkoxy, aryloxy and amino groups represented by R ₉ to R ₁₂ are synonymous with the substitutable groups in R ₁ to R ₄ above. Examples of the thioether group represented by _R9 include alkylthio (methylthio, t-octylthio, etc.), arylthio (phenylthio, etc.), heterocyclic thio (1-phenyltetrazolium, etc.) -5-thio, 5-methyl-1,3,4-oxadiazol-2-thio, etc.) etc.

Examples of the ring that may be formed by R ₉ and X ₂ , R ₉ and X ₃ , or X ₂ and X ₃ include carbocycles with 5 to 7 members, heterocycles with 5 to 6 members, and the like.

In the formula, R ₁₃ , R ₁₄ and R ₁₅ each independently represent a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, a heterocyclic group, an alkoxy group or an amine group, and X ₄ represents -NR ₁₆ -, -O- or -S-. R ₁₆ represents a hydrogen atom, an alkyl group, a cycloalkyl group, an aryl group, an alkoxy group or an amino group. However, when X ₄ is oxygen, R ₁₃ and R ₁₄ form an aromatic ring, and R ₁₅ is not a methyl group.

The alkyl group, cycloalkyl group and aryl group represented by R ₁₃ to R ₁₆ are the same as the above R ₁ to R ₄ . When _X4 is oxygen, examples of the aromatic ring formed by _R13 and _R14 include benzene, naphthalene, pyridine, furan, indole, and thiazole ring.

The compounds represented by the general formulas (L1) to (L3) will be described in detail below by giving specific examples, but the present invention is not limited at all by the following specific examples.

These compounds can be synthesized according to the methods described in Chelate Chemistry (5) Experimental Method of Complex Chemistry [I] (Edited by Nan Jiangtang) and the like. Hereinafter, typical synthesis examples are shown.

(Synthesis of L3-14) 17.8 g of nickel acetate was dissolved in 100 ml of water, and a solution in which 15.0 g of lauryl salicylate was dissolved in 45 ml of acetonitrile was dropped. After stirring for 5 hours under ice cooling, the precipitated solid was obtained by filtration. The structure was determined by NMR spectrum, IR spectrum.

＜Triphenylmethane Derivatives＞ As the triphenylmethane derivative, a compound represented by the following general formula (C) can be preferably used.

(wherein, X represents an amino group, an acylamino group, an alkoxycarbonylamino group, an aryloxycarbonylamine group, a sulfonylamine group, a hydroxyl group, a mercapto group, a carboxyl group, an arylaminocarbonyl group or a carboxyl group , These may have substituents. R ¹¹ ~ R ¹⁵ , R ²¹ ~ R ²⁵ , R ³¹ ~ R ³⁵ each independently represent a hydrogen atom or a substituent. R ¹¹ and R ²¹ , R ¹⁵ and R ³⁵ , or R ²⁵ and ^R31 may be bonded via a single bond or a divalent linking group).

X is preferably an amino group or a hydroxyl group, more preferably a hydroxyl group.

R ¹¹ to R ¹⁵ , R ²¹ to R ²⁵ , and R ³¹ to R ³⁵ each independently represent a hydrogen atom or a substituent, and the following substituent T can be used as the substituent.

As the substituent T, for example, an alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, especially preferably 1 to 8 carbon atoms, such as methyl, ethyl, i -Propyl, t-butyl, n-octyl, n-decyl, n-hexadecyl, cyclopropyl, cyclopentyl, cyclohexyl, etc.), alkenyl (preferably carbon number 2~20, More preferably, it has 2 to 12 carbons, especially preferably 2 to 8 carbons, such as vinyl, allyl, 2-butenyl, 3-pentenyl, etc.), alkynyl (preferably carbon The number is 2-20, more preferably 2-12 carbons, especially preferably 2-8 carbons, for example, propargyl, 3-pentynyl, etc.), aryl (preferably 6-30 carbons) , more preferably carbon number 6~20, especially preferably carbon number 6~12, such as phenyl, p-methylphenyl, naphthyl, etc.), substituted or unsubstituted amino groups (preferably carbon The number is 0-20, more preferably the carbon number is 0-10, especially the carbon number is 0-6, for example, amine group, methylamine group, dimethylamine group, diethylamine group, dibenzyl group amino group, etc.), alkoxy group (preferably having 1 to 20 carbons, more preferably 1 to 12 carbons, especially preferably 1 to 8 carbons, for example, methoxy, ethoxy, butoxy group, etc.), aryloxy group (preferably 6-20 carbons, more preferably 6-16 carbons, especially preferably 6-12 carbons, examples include phenoxy, 2-naphthyloxy, etc.) , acyl group (preferably having 1 to 20 carbons, more preferably 1 to 16 carbons, especially preferably 1 to 12 carbons, for example, acetyl, benzoyl, formyl, trimethyl acetylacetyl, etc.), alkoxycarbonyl (preferably 2 to 20 carbons, more preferably 2 to 16 carbons, especially preferably 2 to 12 carbons, for example, methoxycarbonyl, ethoxy ylcarbonyl, etc.), aryloxycarbonyl (preferably 7 to 20 carbons, more preferably 7 to 16 carbons, especially preferably 7 to 10 carbons, examples include phenoxycarbonyl, etc.), acyloxy Group (preferably having 2 to 20 carbons, more preferably 2 to 16 carbons, especially preferably 2 to 10 carbons, for example, acetyloxy, benzoyloxy, etc.), acylamino (preferably 2 to 20 carbons, more preferably 2 to 16 carbons, especially preferably 2 to 10 carbons, examples include acetylamino, benzoylamino, etc.), alkoxy Carbonylamino group (preferably having 2 to 20 carbons, more preferably 2 to 16 carbons, especially preferably 2 to 12 carbons, examples include methoxycarbonylamino, etc.).

Furthermore, an aryloxycarbonylamine group (preferably 7 to 20 carbons, more preferably 7 to 16 carbons, especially preferably 7 to 12 carbons, for example, phenoxycarbonylamine etc.), sulfonylamino group (preferably having 1 to 20 carbons, more preferably 1 to 16 carbons, especially preferably 1 to 12 carbons, examples include methanesulfonylamino, benzenesulfonyl Amino group, etc.), sulfamoyl group (preferably 0-20 carbons, more preferably 0-16 carbons, especially preferably 0-12 carbons, examples include sulfamoyl, methylamine Sulfonyl, dimethylsulfamoyl, phenylsulfamoyl, etc.), carbamoyl (preferably having 1 to 20 carbons, more preferably 1 to 16 carbons, especially preferably 1 to 2 carbons ~12, for example, carbamoyl, methylcarbamoyl, diethylcarbamoyl, phenylcarbamoyl, etc.), alkylthio (preferably 1 to 20 carbons, more Preferably it has 1 to 16 carbons, especially preferably 1 to 12 carbons, such as methylthio, ethylthio, etc.), arylthio (preferably 6 to 20 carbons, more preferably 6 carbons) ~16, preferably 6~12 carbons, such as phenylthio, etc.), sulfonyl (preferably 1~20 carbons, more preferably 1~16 carbons, especially 1 carbons ~12, for example, methylsulfonyl, toluenesulfonyl, etc.), sulfinyl (preferably 1~20 carbons, more preferably 1~16 carbons, especially preferably 1~12 carbons , such as methanesulfinyl, phenylsulfinyl, etc.), ureido (preferably 1 to 20 carbons, more preferably 1 to 16 carbons, especially preferably 1 to 12 carbons, for example Examples include ureido, methylureido, phenylureido, etc.), amide phosphate (preferably 1 to 20 carbons, more preferably 1 to 16 carbons, especially preferably 1 to 12 carbons, For example, diethylphosphonamide, phenylphosphonamide, etc.), hydroxyl group, mercapto group, halogen atom (for example, fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfonic acid group, carboxyl group, A nitro group, a hydroxylamine group, a sulfinic acid group, a hydrazine group, an imino group, a heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, examples of heteroatoms include nitrogen atoms, Oxygen atom, sulfur atom, specifically, such as imidazolyl, pyridyl, quinolinyl, furyl, piperidyl, morpholinyl, benzozozolyl, benzimidazolyl, benzothiazolyl, etc.), Silyl group (preferably 3-40 carbons, more preferably 3-30 carbons, especially preferably 3-24 carbons, examples include trimethylsilyl, triphenylsilyl, etc.) and the like. Among them, an alkyl group, an aryl group, a substituted or unsubstituted amino group, an alkoxy group, and an aryloxy group are more preferable, and an alkyl group, an aryl group, and an alkoxy group are particularly preferable. These substituents may be further substituted by substituent T. Moreover, when there are two or more substituents, they may be the same or different. In addition, they may be connected to each other to form a ring where possible.

The compound represented by general formula (C) can be obtained commercially, and can also be synthesized by a well-known method.

The compound represented by the general formula (C) will be described in detail below with specific examples, but the present invention is not limited at all by the following specific examples.

＜Barbituric acid compounds＞ As barbituric acid or a derivative thereof, a compound represented by the following general formula (1) can be preferably used.

(式中，R ¹、R ³及R ⁵各自獨立地表示氫原子、碳數1~20的烷基、碳數3~20的環烷基、碳數2~20的烯基或碳數6~20的芳香族基)。

(In the formula, R ¹ , R ³ and R ⁵ each independently represent a hydrogen atom, an alkyl group with 1 to 20 carbons, a cycloalkyl group with 3 to 20 carbons, an alkenyl group with 2 to 20 carbons, or an alkenyl group with 6 carbons ~20 aromatic groups).

The alkyl group with 1 to 20 carbons is preferably an alkyl group with 1 to 10 carbons, more preferably an alkyl group with 1 to 5 carbons, especially preferably an alkyl group with 1 to 3 carbons, especially methyl base or ethyl. The cycloalkyl group having 3 to 20 carbons is preferably a cycloalkyl group having 3 to 10 carbons, more preferably a cycloalkyl group having 4 to 8 carbons. As a specific example of a cycloalkyl group, a cyclopropyl group, a cyclopentyl group, a cyclohexyl group etc. are mentioned, for example, Cyclohexyl group is especially preferable.

The alkenyl having 2 to 20 carbons is preferably an alkenyl having 2 to 10 carbons, more preferably an alkenyl having 2 to 5 carbons. The aromatic group having 6 to 20 carbon atoms may be an aromatic hydrocarbon group or an aromatic heterocyclic group, but is preferably an aromatic hydrocarbon group. The aromatic hydrocarbon group is preferably a phenyl group or a naphthyl group, more preferably a phenyl group.

R ¹ , R ³ and R ⁵ may have substituents. As a substituent, there is no special limitation, for example, an alkyl group (preferably having 1 to 10 carbon atoms, such as methyl, ethyl, isopropyl, t-butyl, pentyl, heptyl, 1- Ethylpentyl, benzyl, 2-ethoxyethyl, 1-carboxymethyl, etc.), alkenyl (preferably carbon number 2~20, such as vinyl, allyl, oleyl, etc.), alkyne (preferably 2-20 carbons, such as ethynyl, butadiynyl, phenylethynyl, etc.), cycloalkyl (preferably 3-20 carbons, such as cyclopropyl, cyclopentyl, cyclo Hexyl, 4-methylcyclohexyl, etc.), aryl (preferably carbon number 6~26, such as phenyl, 1-naphthyl, 4-methoxyphenyl, 2-chlorophenyl, 3-methyl phenyl, etc.), heterocyclic group (preferably a heterocyclic group with 0 to 20 carbon atoms, the heteroatom constituting the ring is preferably an oxygen atom, a nitrogen atom, a sulfur atom, a 5- or 6-membered ring and can be a benzene ring or a heterocyclic Ring condensation, the ring can be saturated ring, unsaturated ring, aromatic ring, such as 2-pyridyl, 4-pyridyl, 2-imidazolyl, 2-benzimidazolyl, 2-thiazolyl, 2-㗁Azolyl, etc.), alkoxy (preferably 1 to 20 carbons, such as methoxy, ethoxy, isopropoxy, benzyloxy, etc.), aryloxy (preferably 6 to 26 carbons , such as phenoxy, 1-naphthyloxy, 3-methylphenoxy, 4-methoxyphenoxy, etc.), alkylthio (preferably carbon number 1~20, such as methylthio, ethyl Thio, isopropylthio, benzylthio, etc.), arylthio (preferably carbon number 6~26, such as phenylthio, 1-naphthylthio, 3-methylphenylthio, 4-methoxy phenylthio, etc.), acyl (including alkylcarbonyl, alkenylcarbonyl, arylcarbonyl, heterocyclic carbonyl, carbon number is preferably less than 20, such as acetyl, trimethylacetyl, acryl , methacryl, benzoyl, nicotinyl, etc.), arylalkyl, alkoxycarbonyl (preferably carbon number 2~20, such as ethoxycarbonyl, 2-ethylhexyl Oxycarbonyl, etc.), aryloxycarbonyl (preferably 7 to 20 carbons, such as phenoxycarbonyl, naphthyloxycarbonyl, etc.), amino (including amino, alkylamino, arylamino, Heterocyclic amino group, preferably with carbon number 0~20, such as amino group, N,N-dimethylamino group, N,N-diethylamino group, N-ethylamino group, aniline group, 1- pyrrolidinyl, piperidinyl, morpholinyl, etc.), sulfonamide (preferably carbon number 0~20, such as N,N-dimethylsulfonamide, N-phenylsulfonamide, etc. ), sulfamoyl group (preferably carbon number 0~20, such as N,N-dimethylsulfamoyl group, N-phenylsulfamoyl group, etc.), acyloxy group (preferably carbon number 1 ~20, such as acetyloxy, benzoyloxy, etc.), aminoformyl (preferably carbon number 1~20, such as N,N-dimethylaminoformyl, N-phenylaminoformyl Acyl amino group, etc.), acyl amino group (preferably carbon number 1~20, such as acetyl amino group, acryl amino group, benzoyl amino group, nicotinyl amino group, etc.), cyano group, A hydroxyl group, a mercapto group or a halogen atom (for example, a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, etc.). The aforementioned substituents that R ¹ , R ³ and R ⁵ may have may further have the aforementioned substituents. Among the above-mentioned substituents that each group of R ¹ , R ³ and R ⁵ may have, an alkyl group, an aryl group, an alkoxy group, and an acyl group are preferable.

<Hansen Solubility Parameter (HSP Value)> The δP (polar force) of the Hansen solubility parameter (HSP value) of the non-organic acid system of the present invention is preferably in the range of 5-9 MPa ^0.5 . When δP is 5 MPa ^0.5 or more, non-organic acid and polyiodine sufficiently perform charge repulsion. When δP is 9MPa ^0.5 or less, it has affinity with resin and suppresses bleeding. Also, the alignment of polyiodine in the polarizer layer can be maintained by moderate repulsive force.

Furthermore, the value of the ratio of δD (dispersion force) to δP (polar force) of the HSP value of the non-organic acid preferably satisfies the following formula. 2<δD (dispersion force)/δP (polar force)<4 Within the above range, the non-organic acid has moderate polarity and is dispersed, so the movement of polyiodine can be more effectively suppressed.

In addition, the SP value and the HSP value will be described below. Hildebrand's SP value (solubility parameter; δ) has conventionally been used as an index for evaluating the physical properties of a substance, especially the dissolution behavior of a solvent. The "SP value" is a physical property value inherent to a substance expressed by the square root of the condensation energy density of the substance. In addition, this SP value is divided into three components of dispersive force term (δD), polar term (δP), and hydrogen bond term (δH) by Hansen, and the proposed Hansen solubility parameter is used as a parameter considering the polarity of the substance (HSP value) is represented by the following formula. SP value=(δD ² +δP ² +δH ² ) ^0.5

The Hansen solubility parameter (HSP value) is based on the consideration that "two substances with similar intermolecular interactions are easily soluble in each other", and consists of the following three parameters. These three parameters can be regarded as three-dimensional space (also known as "Hansen space") coordinates. The closer the distance between the coordinates of the two substances is, the higher the mutual affinity is, and they are considered to be easily soluble. δD: energy caused by the dispersion force between molecules δP: Energy due to dipole interactions between molecules δH: energy due to intermolecular hydrogen bonds

Furthermore, the method of calculating δD, δP, and δH in the Hansen solubility parameters is not particularly limited, and the calculation can be performed by inputting the chemical structure into the software, or can be calculated experimentally, but it is preferably calculated by inputting the chemical structure into the software.

As the HSP value, registered values or estimated values in HSPiP 5th Edition 5.0.10.1 of commercially available software can be used. This software can be obtained from websites such as https://www.hansen-solbility.com/. Also, the calculation method of the HSP based on this software is, for example, based on the document "Hansen Solubility Parameters: A User's Handbook, Second Edition" by C. M. Hansen et al. (CRC Press, 2007).

It is preferable that the iodine migration inhibitor of the present invention further contains sulfate ions, and the content of the sulfate ions is within the range of 1 to 100 mass ppm relative to the total solid mass of the resin film for polarizing plates. By containing sulfate ions within the above range, the polarity of the non-organic acid is stabilized in the resin film for polarizing plates, and sufficient charge repulsion with polyiodine is performed.

As a method for measuring the content of sulfate ions relative to the total mass of the solid content of the resin film for polarizing plates, a capillary electrophoresis device is used to compare with the standards of each ion containing sulfate ions and compare the swimming time (in HPLC terms) retention time) for quantification.

[1.3 Other additives] The resin film for polarizing plates of this invention may further contain other components other than the above as needed. Examples of other components include antioxidants, rubber particles, matting agents (fine particles) to be described later, plasticizers, ultraviolet absorbers, and the like. Among them, the antioxidant is preferably contained from the viewpoint of contributing to the improvement of the storage stability of the film over time, and the rubber particles are preferably contained from the viewpoint of imparting toughness (flexibility) to the film.

＜Antioxidant＞ As the antioxidant, well-known ones can be used. In particular, lactone-based, sulfur-based, phenol-based, double bond-based, hindered amine-based, and phosphorus-based compounds can be preferably used.

As said lactone compound, "Irgafos XP40, Irgafos XP60 (trade name)" marketed by BASF Japan Co., Ltd. etc. are mentioned, for example.

As said sulfur compound, "Sumilizer (registered trademark) TPL-R" and "Sumilizer (registered trademark) TP-D" marketed by Sumitomo Chemical Co., Ltd. are mentioned, for example.

As the above-mentioned phenolic compound, for example, those having a structure of 2,6-dialkylphenol are preferable, for example, "Irganox (registered trademark) 1076" commercially available from BASF Japan Co., Ltd., "Irganox (registered trademark) 1076" and "Irganox (registered trademark) Trademark) 1010", "ADK STAB (registered trademark) AO-50" marketed by ADEKA Co., Ltd., etc.

Examples of the above-mentioned double bond compound include “Sumilizer (registered trademark) GM” and “Sumilizer (registered trademark) GS” commercially available from Sumitomo Chemical Co., Ltd., and the like. Relative to the total mass of the thermoplastic resin, the content of the double bond compound is 0.05-20% by mass, preferably 0.1-1% by mass.

Examples of the hindered amine compound include "Tinuvin (registered trademark) 144" and "Tinuvin (registered trademark) 770" commercially available from BASF Japan Co., Ltd., "ADK STAB (registered trademark) LA-52".

Examples of the above-mentioned phosphorus compounds include "Sumilizer (registered trademark) GP" marketed by Sumitomo Chemical Co., Ltd., "ADK STAB (registered trademark) PEP-24G" marketed by ADEKA Co., Ltd., "ADK STAB (registered trademark) PEP-36" and "ADK STAB (registered trademark) 3010", "IRGAFOS P-EPQ" commercially available from BASF Japan Co., Ltd., commercially available from Sakai Chemical Industry Co., Ltd. "GSY-P101".

Furthermore, as an acid scavenger, a compound having an epoxy group as described in US Pat. No. 4,137,201 may also be contained.

The content of the antioxidants other than the above-mentioned double bond compound is preferably in the range of 0.0001 to 0.01% by mass, more preferably in the range of 0.002 to 0.01% by mass, based on the total mass of the thermoplastic resin.

These antioxidants may be used alone or in combination of two or more. For example, it is preferable to use a lactone type, a phosphorus type, a phenol type, and a double bond type compound together.

＜Rubber Particles＞ The rubber particles are particles comprising a rubber-like polymer. The rubber-like polymer is a soft cross-linked polymer with a glass transition temperature of 20°C or lower. Examples of such cross-linked polymers include butadiene-based cross-linked polymers, (meth)acrylic-based cross-linked polymers, and organosiloxane-based cross-linked polymers. Among them, a (meth)acrylic cross-linked polymer is preferable, and an acrylic crosslinked polymer is more preferable from the standpoint that the difference in refractive index with the (meth)acrylic resin is small and the transparency of the resin film for polarizing plates is less likely to be impaired. Cross-linked polymer (acrylic rubber-like polymer).

That is, the rubber particles are preferably particles containing the acrylic rubber-like polymer (a).

Regarding the acrylic rubber-like polymer (a): The acrylic rubber-like polymer (a) is a cross-linked polymer containing an acrylate-derived structural unit as a main component. What is contained as a main component means that content of the structural unit derived from an acrylate falls within the range mentioned later. The acrylic rubber-like polymer (a) preferably contains a structural unit derived from an acrylate, a structural unit derived from another monomer copolymerizable therewith, and a polymer having two or more radically polymerizable groups in one molecule. (Non-conjugated reactive double bond) cross-linked polymer of structural units of polyfunctional monomers.

Acrylate is preferably methyl acrylate, ethyl acrylate, n-propyl acrylate, n-butyl acrylate, second butyl acrylate, isobutyl acrylate, benzyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate , Alkyl acrylate with 1 to 12 carbon atoms in the alkyl group such as n-octyl acrylate. Acrylates may be used alone or in combination of two or more.

The content of the structural unit derived from acrylate is preferably in the range of 40 to 80% by mass, more preferably in the range of 50 to 80% by mass, based on all the structural units constituting the acrylic rubber-like polymer (a1). When the content of the acrylate is within the above range, it is easy to impart sufficient toughness to the film.

Other monomers that can be copolymerized are those other than polyfunctional monomers among the monomers that can be copolymerized with acrylate. That is, the copolymerizable monomer does not have two or more radically polymerizable groups. Examples of copolymerizable monomers include methacrylates such as methyl methacrylate; styrenes such as styrene and methylstyrene; (meth)acrylonitriles; (meth)acrylic Amides; (meth)acrylic acid. Among them, other copolymerizable monomers preferably include styrenes. Other copolymerizable monomers may be used alone or in combination of two or more.

The content of the structural units derived from other copolymerizable monomers is preferably in the range of 5 to 55% by mass, more preferably 10 to 45% by mass, relative to all the structural units constituting the acrylic rubber-like polymer (a). % range.

Examples of polyfunctional monomers include allyl (meth)acrylate, triallyl cyanurate, triallyl isocyanurate, diallyl phthalate, malic acid Diallyl ester, divinyl adipate, divinylbenzene, ethylene glycol di(meth)acrylate, diethylene glycol (meth)acrylate, triethylene glycol di(meth)acrylate , Trimethylolpropane Tri(meth)acrylate, Tetramethylolmethane Tetra(meth)acrylate, Dipropylene Glycol Di(meth)acrylate, Polyethylene Glycol Di(meth)acrylate.

The content of the structural unit derived from the polyfunctional monomer is preferably in the range of 0.05 to 10% by mass, more preferably 0.1 to 5% by mass, relative to all the structural units constituting the acrylic rubber-like polymer (a). within range. When the content of the polyfunctional monomer is 0.05% by mass or more, the degree of crosslinking of the obtained acrylic rubber-like polymer (a) is easily increased, and the hardness and rigidity of the obtained film are less likely to be impaired. Moreover, the toughness of this thin film is hard to be impaired by being 10 mass % or less.

The monomer composition constituting the acrylic rubber-like polymer (a) can be measured, for example, by the peak area ratio detected by thermal decomposition GC-MS.

The glass transition temperature (Tg) of the rubbery polymer is preferably at most 0°C, more preferably at most -10°C. When the glass transition temperature (Tg) of a rubbery polymer is 0 degreeC or less, moderate toughness can be imparted to this film. The glass transition temperature (Tg) of the rubbery polymer was measured in the same manner as above.

The glass transition temperature (Tg) of the rubbery polymer can be adjusted by the composition of the rubbery polymer. For example, in order to lower the glass transition temperature (Tg) of the acrylic rubber-like polymer (a), it is preferable to increase the number of carbon atoms of the alkyl group in the acrylic rubber-like polymer (a) to 4 or more. The mass ratio of other copolymerized monomers (for example, 3 or more, preferably 4 to 10).

The particles comprising the acrylic rubber-like polymer (a) may be particles made of the acrylic rubber-like polymer (a), or may be a hard cross-linked polymer (c) having a glass transition temperature of 20°C or higher. ) and the particles of the soft layer made of acrylic rubber-like polymer (a) arranged around it (also referred to as "elastomer"); Particles of an acrylic graft copolymer obtained by polymerizing a mixture of monomers such as methacrylate in at least one stage in the presence of the polymer (a). The particles made of the acrylic graft copolymer may be core-shell particles having a core comprising the acrylic rubber-like polymer (a) and a shell covering it.

Regarding core-shell rubber particles comprising acrylic rubber-like polymers: (core) The core part contains an acrylic rubber-like polymer (a), and may further contain a hard crosslinked polymer (c) if necessary. That is, the core may have a soft layer made of an acrylic rubber-like polymer and a hard layer made of a hard cross-linked polymer (c) arranged inside it.

The crosslinked polymer (c) may be a crosslinked polymer mainly composed of methacrylate. That is, the crosslinked polymer (c) preferably contains at least one of a structural unit derived from an alkyl methacrylate, a structural unit derived from another monomer copolymerizable therewith, and a structural unit derived from a polyfunctional monomer. cross-linked polymer.

The alkyl methacrylate may be the above-mentioned alkyl methacrylate, and other copolymerizable monomers may be the above-mentioned styrenes or acrylates, and the polyfunctional monomers may be those listed as the above-mentioned polyfunctional monomers. the same.

The content of the structural unit derived from an alkyl methacrylate is preferably within a range of 40 to 100% by mass relative to all structural units constituting the crosslinked polymer (c). The content of the structural units derived from other copolymerizable monomers is preferably in the range of 60 to 0% by mass relative to all the structural units constituting the other crosslinked polymer (c). The content of the structural unit derived from the polyfunctional monomer is preferably in the range of 0.01 to 10% by mass relative to all the structural units constituting other crosslinked polymers.

(shell) The shell portion contains a methacrylic polymer (b) (other polymer) containing a structural unit derived from methacrylate as a main component graft-bonded to the acrylic rubber-like polymer (a). What is contained as a main component means that content of the structural unit derived from a methacrylate falls within the range mentioned later.

The methacrylate constituting the methacrylic polymer (b) is preferably an alkyl methacrylate having 1 to 12 carbon atoms in the alkyl group such as methyl methacrylate. Methacrylates may be used alone or in combination of two or more.

The content of methacrylate is preferably 50% by mass or more with respect to all the structural units constituting the methacrylic polymer (b). When content of methacrylate is 50 mass % or more, compatibility with the methacrylic resin containing the structural unit derived from methyl methacrylate as a main component becomes easy to acquire. From the above viewpoint, the content of methacrylate is more preferably 70 mass % or more with respect to all the structural units constituting the methacrylic polymer (b).

The methacrylic polymer (b) may further contain a structural unit derived from another monomer copolymerizable with methacrylate. Examples of other copolymerizable monomers include acrylates such as methyl acrylate, ethyl acrylate, and n-butyl acrylate; benzyl (meth)acrylate, dicyclopentyl (meth)acrylate, (meth)acrylate (meth)acrylic monomers having alicyclic rings, heterocyclic rings or aromatic rings (ring-containing (meth)acrylic monomers) such as phenoxyethyl acrylate.

The content of the structural unit derived from the copolymerizable monomer is preferably at most 50% by mass, more preferably at most 30% by mass, relative to all the structural units constituting the methacrylic polymer (b).

In this embodiment, since the resin film for polarizing plates is not stretched, the shape of the rubber particles may be close to a true spherical shape. That is, when observing the cross section or surface of the film, the aspect ratio of the rubber particles is preferably about 1 to 2.

The average particle diameter of the rubber particles is preferably in the range of 100-400 nm. When the average particle size of the rubber particles is 100 nm or more, it is easy to impart sufficient toughness or stress relaxation to the film, and when it is 400 nm or less, the transparency of the film is less likely to be impaired. Based on the above viewpoint, the average particle diameter of the rubber particles is more preferably in the range of 150 to 300 nm.

The average particle diameter of rubber particles can be calculated by the following method.

The average particle diameter of the rubber particles can be measured as the average value of the circle-equivalent diameters of 100 particles obtained by SEM photography or TEM photography on the surface or slice of the resin film for polarizing plates. The circle-equivalent diameter can be obtained by converting the projected area of the particles obtained by photography into the diameter of a circle having the same area. At this time, rubber particles observed by SEM observation and/or TEM observation at a magnification of 5000 times were used for calculation of the average particle diameter.

The content of the rubber particles is not particularly limited, but is preferably within a range of 5 to 40% by mass, more preferably within a range of 7 to 30% by mass, relative to the total mass of the film.

[1.4 Physical properties] <Phase difference Ro and Rt> The resin film for polarizing plates of the present invention not only functions as a protective layer but also functions as an optical film such as a retardation film.

For example, from the point of view of using this film as a retardation film for IPS mode, the retardation Ro in the in-plane direction measured in an environment with a measurement wavelength of 590nm and 23°C･55%RH is preferably in the range of 0 to 10nm. More preferably within the range of 0~5nm. The retardation Rt in the thickness direction of the thin film is preferably in the range of -40~40nm, more preferably in the range of -25~25nm.

Each of Ro and Rt is defined by the following formula.

Formula (a): Ro=(n _x -n _y )×d Formula (b): Rt=((n _x +n _y )/2-n _z )×d (where n _x represents the resin for polarizing plate The refractive index in the direction of the in-plane slow axis of the film (the direction in which the refractive index becomes the largest), _ny represents the refractive index in the direction perpendicular to the in-plane slow axis of the resin film for polarizing plates, _nz represents the refractive index of the resin film for polarizing plates The refractive index in the thickness direction, d represents the film thickness (nm) of the resin film for polarizing plates). The in-plane slow axis system of the thin film can be confirmed with an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by AXOMETRICS).

Ro and Rt can be measured by the following methods.

1) Condition the film for 24 hours in an environment of 23°C･55%RH. The average refractive index of the thin film was measured with an Abbe refractometer, and the film thickness d was measured using a commercially available micrometer.

2) Using an automatic birefringence meter Axo Scan (Axo Scan Mueller Matrix Polarimeter: manufactured by AXOMETRICS Co., Ltd.), the retardation Ro and Rt at the measurement wavelength of 590 nm of the film after humidity adjustment were respectively measured in an environment of 23° C. and 55% RH.

The retardation Ro and Rt of the film can be adjusted by, for example, the type of thermoplastic resin, stretching conditions, and drying conditions. For example, by increasing the drying temperature, Rt can be lowered.

≪2 Manufacturing method of resin film for polarizing plate of the present invention≫ The form of the resin film for polarizing plates of the present invention is not particularly limited, but is preferably in the form of a belt, for example. That is, it is preferable that the resin film for polarizing plates of this invention is wound up into the roll shape in the direction orthogonal to the width direction, and it becomes a roll body.

[Manufacturing method] The method for producing a resin film for a polarizing plate of the present invention comprises: 1) a step of obtaining a solution for a resin film for a polarizing plate, 2) a step of applying the obtained solution for a resin film for a polarizing plate to the surface of a support, and 3) A step of removing the solvent from the applied solution for a resin film for a polarizing plate to form a resin film for a polarizing plate.

1) Step of obtaining a solution for a resin film for a polarizing plate A solution for a resin film for a polarizing plate (also referred to as a "solution for a film" or a "coating solution") containing a thermoplastic resin, an iodine transfer inhibitor, and a solvent is prepared. The solution for the thin film may suitably contain sulfate ions.

The film solution is prepared by adding a powder or liquid (in the case of metal oxide particles, a dispersion liquid) iodine transfer inhibitor, a solvent, further adding sulfuric acid as the case may be, stirring, and then adding a resin and stirring.

When using metal oxide particles as the iodine transfer inhibitor, the metal oxide particles are dispersed in the form of particles in a solvent used for a thin film solution described below to obtain a dispersion. The dispersion of metal oxide particles can be carried out using mechanical energy. Such a disperser system is not particularly limited. As mentioned above, as examples, low-speed shear dispersers, high-speed shear dispersers, and friction dispersers can be mentioned. , High-pressure jet disperser, ultrasonic homogenizer, etc. Ultrasonic disperser or high-pressure impact disperser wet micronizer, etc.

The solvent used for the solution for the resin film for polarizing plates is not particularly limited as long as it can disperse or dissolve the resin well. For example, as the organic solvent used in the present invention, alcohols (methanol, ethanol or glycols, triols, tetrafluoropropanol, etc.), glycols, celloxal, ketones (acetone, methyl ethyl alcohol, etc.) ketone, etc.), carboxylic acids (formic acid, acetic acid, etc.), carbonates (ethylene carbonate, propylene carbonate, etc.), esters (ethyl acetate, propyl acetate, etc.), ethers (isopropyl ether , THF, etc.), amides (dimethyl sulfide, etc.), hydrocarbons (heptane, etc.), nitriles (acetonitrile, etc.), aromatics (cyclohexylbenzene, toluene, xylene, chlorobenzene, etc.), Alkyl halides (dichloromethane (also known as "methylene chloride"), etc.), amines (1,4-diazabicyclo[2.2.2]octane, diazabicycloundecene, etc.) , Lactone series, etc.

Among them, as the solvent for the thin film solution, those having a boiling point of 100° C. or lower under atmospheric pressure are preferable, and chlorine-based solvents are preferable. Specifically, dichloromethane (also known as "methylene chloride") is more preferred. Since the solvent is dichloromethane, it has high solubility and is easy to handle, and has high volatility and fast drying speed, so it is easy to adjust the film quality of the coating film.

In addition, a hydrophilic solvent may be added to the solvent of the thin film solution. As a hydrophilic solvent, a ketone, alcohol, etc. are mentioned, for example, Alcohol is preferable. More preferably, it is isopropanol, ethanol, methanol, etc., most preferably, it is methanol. The added amount is preferably in the range of 1 to 20% by mass, more preferably in the range of 3 to 10% by mass, based on the total mass of the solvent of the thin film solution.

The concentration of the resin in the film solution is preferably within a range of, for example, 1.0 to 20% by mass relative to the total mass of the film solution from the viewpoint of easy adjustment of the viscosity to the range described later. Also, from the viewpoint of reducing the amount of shrinkage of the coating film during drying, the concentration of the resin in the film solution is preferably moderately high, more preferably in the range of more than 5% by mass and not more than 20% by mass, and particularly preferably It is within the range of more than 5% by mass and not more than 15% by mass.

By adjusting the concentration of the resin, the time until the coating film is formed is shortened, and the drying time and the surface state of the film can be controlled. Also, by using a mixed solvent appropriately, the concentration of the resin can be increased.

The viscosity of the film solution is not particularly limited as long as it can form a polarizing plate resin film with a desired film thickness, but it is preferably in the range of 5 to 5000 mPa·s, for example. When the viscosity of the film solution is above 5mPa･s, it is easy to form a film with a moderate film thickness, and when it is below 5000mPa･s, it is possible to suppress the occurrence of uneven film thickness due to the increase in the viscosity of the solution. The viscosity of the film solution is more preferably in the range of 100 to 1000 mPa･s from the above point of view. The viscosity of the film solution can be measured with an E-type viscometer at 25°C.

2) Step of providing solution for resin film for polarizing plate Next, the obtained solution for a thin film is applied to the surface of the support. Specifically, the solution for the obtained thin film is coated on the surface of the support.

＜Support＞ The support system supports when forming a polarizing plate with a resin film, and usually uses a resin film. The thickness of the support is preferably 50 μm or less. The thickness of the support body must be a thin film and a certain degree of strength (rigidity) as the support body, so it is preferably within the range of 15-45 μm, more preferably within the range of 20-40 μm.

As the resin used for the resin film of the support, cellulose ester resins, cycloolefin resins, polypropylene resins, acrylic resins, polyester resins, polyarylate resins, and styrene resins or their Among the composite resins, polyester-based resins are preferably used as resins excellent in storage stability in a high-humidity environment.

Examples of resin films include polyester resins (such as polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), polybutylene naphthalate (PBN), etc.), etc. Among these, polyester-based resin films made of polyethylene terephthalate (PET) or polyethylene naphthalate (PEN) are preferred from the viewpoint of ease of handling.

The resin film may be heat-treated (heat-relaxed) or stretched.

The heat treatment is performed in order to reduce the residual stress of the resin film (for example, the residual stress accompanying stretching, etc.). The temperature system is not particularly limited, but when the glass transition temperature of the resin constituting the resin film is taken as Tg, it can be carried out at (Tg+60)~(Tg+180)°C.

The stretching treatment is performed to increase the residual stress of the resin film, and the stretching treatment is preferably performed, for example, in biaxial directions of the resin film. The stretching treatment can be carried out under arbitrary conditions, for example, it can be carried out within the range of about 120 to 900% of the stretching ratio. Whether or not the resin film is stretched can be confirmed, for example, by whether or not there is an in-plane slow axis (the axis extending in the direction in which the refractive index becomes the maximum). Stretching treatment may be performed before lamination of functional layers or after lamination, but it is preferable to perform stretching before lamination.

A commercially available polyester film (simply referred to as polyester film) can be used, for example, polyethylene terephthalate film TN100 (manufactured by Toyobo Co., Ltd.), MELINEX (registered trademark) ST504 (Teijin DuPont Film Co., Ltd.), etc.

The support may further have a release layer on the surface of the resin film. When the resin film for polarizing plates of this invention is produced by having a release layer, a support body can be peeled off easily.

The release layer may contain a well-known release agent and is not particularly limited. Examples of the release agent contained in the release layer include silicone-based release agents and non-silicone-based release agents.

Examples of silicone-based release agents include well-known silicone-based resins. Examples of non-silicone-based release agents include long-chain alkyl pendant polymers obtained by reacting long-chain alkyl isocyanates with polyvinyl alcohol or ethylene-vinyl alcohol copolymers, and olefin-based resins (such as Copolymerized polyethylene, cyclic polyolefin, polymethylpentene), polyarylate resin (such as polycondensate of aromatic dicarboxylic acid component and dihydric phenol component), fluororesin (such as polytetrafluoroethylene (PTFE ), polyvinylidene fluoride (PVDF), polyvinyl fluoride (PVF), PFA (copolymer of tetrafluoroethylene and perfluoroalkoxyethylene), FEP (copolymer of tetrafluoroethylene and hexafluoropropylene), ETFE (copolymer of tetrafluoroethylene and ethylene)), etc.

The thickness of the release layer is not particularly limited as long as the desired peelability can be exhibited, but is preferably within a range of 0.1 to 1.0 μm, for example.

The support may also contain plasticizers as additives. The plasticizer is not particularly limited, but examples include polyol ester-based plasticizers, phthalate-based plasticizers, citric acid-based plasticizers, fatty acid ester-based plasticizers, and phosphate ester-based plasticizers. , polycarboxylate-based plasticizers, polyester-based plasticizers, etc.

Moreover, a support body may contain an ultraviolet absorber. Examples of the ultraviolet absorber to be used include benzotriazole-based, 2-hydroxybenzophenone-based, and phenyl salicylate-based agents. Specifically, 2-(5-methyl-2-hydroxyphenyl)benzotriazole, 2-[2-hydroxy-3,5-bis(α,α-dimethylbenzyl)benzene Base]-2H-benzotriazole, 2-(3,5-di-tert-butyl-2-hydroxyphenyl)benzotriazole and other triazoles, 2-hydroxy-4-methoxydiphenyl Benzophenones such as ketone, 2-hydroxy-4-octyloxybenzophenone, and 2,2'-dihydroxy-4-methoxybenzophenone, etc.

Furthermore, the support used in the present invention preferably contains fine particles in order to improve transportability.

Examples of fine particles include silica, titania, alumina, zirconia, calcium carbonate, calcium carbonate, talc, clay, fired kaolin, fired calcium silicate, hydrated calcium silicate, Aluminum silicate, magnesium silicate and calcium phosphate.

In addition, fine particles of an organic compound can also be preferably used as the fine particles. Examples of organic compounds include polytetrafluoroethylene, cellulose acetate, polystyrene, polymethyl methacrylate, polypropyl methacrylate, polymethyl acrylate, polyethylene carbonate, acrylic Styrene resin, silicone resin, polycarbonate resin, benzoguanamine resin, melamine resin, polyolefin powder, polyester resin, polyamide resin, polyimide resin, Or pulverized and fractionated organic polymer compounds such as polyvinyl fluoride resin and starch, or polymer compounds synthesized by suspension polymerization.

From the viewpoint of lowering the turbidity, the fine particles are preferably those containing silicon, particularly preferably silicon dioxide. As fine particles of silica, commercially available products can be used, for example, Aerosil (registered trademark) R972, R972V, R974, R812, 200, 200V, 300, R202, OX50, TT600 (manufactured by Nippon Aerosil Co., Ltd.) wait.

As the manufacturing method of the support used in the present invention, the usual inflation method, T-die method, calendering method, cutting method, casting method, emulsification method, hot pressing method, etc. can be used, but from the suppression of coloring, the suppression of From the viewpoint of foreign matter defects, optical defects such as suppression of die line, etc., the film production method is preferably solution casting method and melt casting method. In addition, in the case of the solution casting method, the temperature of the processing step is relatively low, so various additives can be used to provide further functions.

When forming a film by a solution casting method, the production method of the support preferably includes a step of dissolving and dispersing additives such as thermoplastic resin and the above-mentioned fine particles in a solvent to prepare a coating solution (dissolving step; coating solution preparation step) ), the step of casting the coating solution on the infinitely moving endless metal support (casting step), the step of making the cast coating solution become a web (web) and drying (solvent evaporation step), from the metal The step of peeling the support (peeling step), the step of drying, stretching, and maintaining the width (stretching, width maintaining, and drying step), and the step of winding the processed film into a roll (winding step).

It is preferable to form the resin film for polarizing plates of this invention by the following method using the support manufactured as mentioned above.

The coating method of the solution for the resin film for polarizing plates is not particularly limited, and for example, well-known methods such as post-roll coating, gravure coating, spin coating, wire bar coating, and roll coating can be used. method. In particular, the back coating method is preferable from the viewpoint of being able to form a thin and uniform coating film.

3) Step of forming resin film for polarizing plate Next, the solvent is removed from the solution for the resin film for polarizing plates provided to the support body, and the resin film for polarizing plates is formed.

Specifically, the solution for thin film applied to the support is dried. Drying can be performed by blowing air or heating, for example. Among them, from the viewpoint of easily suppressing curling of the film, it is preferable to dry by blowing air, and from the viewpoint of controlling variation in film thickness described below, it is preferable to cause a difference in wind speed between the initial stage of drying and the second half of drying. Specifically, the variation in film thickness tends to increase when the initial wind speed is high, and to decrease when the initial wind speed is low.

Therefore, by adjusting the drying conditions (such as drying temperature, drying air volume, drying time, etc.) to control the density of the resin film for polarizing plates, the thickness of the film can be adjusted to the range satisfying the following formula.

5<|Average (B)-average film thickness (A)|/average film thickness (A)×100＜20(%) Here, the average film thickness value (A) is the average value of film thickness values at 10 points arbitrarily extracted from the film.

When the value shown in the above formula exceeds 5%, the surface has moderate unevenness, and the adhesion with the upper layer is improved. When it is less than 20%, the unevenness of the surface is not too large, and the coatability and smoothness of the upper layer are not affected.

A commercially available film thickness measuring device can be used for the measurement of the film thickness, and as a film thickness measuring system, F20-UV (manufactured by FILMETRICS, Inc.) is mentioned, for example.

In addition, it is preferable that the deviation ρ of the thickness of the resin film for polarizing plates be adjusted within the range of 0.5±0.2 μm. Also, from the viewpoint of improving the adhesion to the upper layer, it is preferable to adjust the film quality to a thinning direction. Specifically, it is preferable to increase the drying speed, preferably in the range of 0.0015~0.05kg/hr･m ² , more preferably in the range of 0.002~0.05kg/hr･m ² .

The drying speed is expressed by the mass of solvent evaporated per unit time and unit area. Drying speed can usually be adjusted by drying temperature. Although the drying temperature also depends on the type of solvent used, for example, it is preferably 50~200°C (in the range of (Tb-50)~(Tb+50)°C relative to the boiling point Tb of the solvent used). The temperature control system can be carried out in multiple stages. After a certain degree of drying, drying at a higher temperature can control the drying speed and film quality.

The resin film for polarizing plates of the present invention is as described above, preferably in the form of a belt. Therefore, it is preferable that the manufacturing method of the laminated film of this embodiment further includes (4) the step of winding the tape-shaped laminated film into a roll to form a roll body.

4) The step of winding up the resin film for polarizing plates to obtain a roll body The obtained resin film for a strip-shaped polarizing plate was wound up into a roll in a direction perpendicular to its width direction to form a roll body.

The length of the resin film for band-shaped polarizing plates is not particularly limited, but may be, for example, within a range of 100 to 10000 m. Moreover, the width of the resin film for band-shaped polarizing plates is preferably at least 1 m, more preferably within a range of 1.1 to 4 m. From the viewpoint of improving the uniformity of the film, it is more preferably in the range of 1.3 to 2.5 m.

[manufacturing device] The manufacturing method of the resin film for polarizing plates of this invention can be performed by the manufacturing apparatus shown in FIG. 1, for example.

1 is a model diagram of a manufacturing device B200 for implementing the manufacturing method of a resin film for polarizing plates of the present invention. The manufacturing device B200 has a supply part B210, a coating part B220, a drying part B230, a cooling part B240 and a winding part B250. Ba~Bd represent the conveyance roller which conveys the support body B110.

The supply part B210 has the sending-out device (not shown) which sends out the roll body B201 of the tape-shaped support body B110 wound on the winding core.

The coating unit B220 is a coating device, and has a support roll B221 holding the support body B110, a coating head B222 for coating a solution for a resin film for a polarizing plate on the support body B110 held by the support roll B221, and a coating head B222. The decompression chamber B223 installed on the upstream side of B222.

The flow rate of the solution for the resin film for polarizing plates discharged from the coating head B222 can be adjusted with the pump which is not shown in figure. The flow rate of the solution for the polarizing plate resin film discharged from the coating head B222 is the amount that can stably form a coating layer with a specified thickness when continuously coating under the conditions of the previously adjusted coating head B222 .

The decompression chamber B223 is a mechanism for stabilizing the beads formed between the solution for the resin film for polarizing plates from the coating head B222 and the support B110 (retention of the coating solution) during coating, and can be adjusted. decompression degree. The decompression chamber B223 is connected to a decompression blower (not shown), and can depressurize the inside. The decompression chamber B223 is in a state of no air leakage, and the gap between the back-up roll and the back-up roll is also adjusted narrowly, and stable beads of the coating liquid can be formed.

The drying part B230 is a drying device for drying the coating film applied on the surface of the support body B110, and has a drying chamber B231, an inlet B232 for a drying gas, and an outlet B233. The temperature and air volume of the drying air can be appropriately determined according to the type of the coating film and the type of the support B110. By setting the drying air temperature, air volume, drying time and other conditions of the drying section B230, the amount of residual solvent in the dried coating film can be adjusted. The residual solvent amount of the dried coating film can be measured by comparing the unit mass of the dried coating film with the unit mass of the fully dried coating film.

(residual solvent amount) After the resin film for polarizing plates of this invention is obtained by coating the solution for films, the solvent derived from the said solution remains. The amount of residual solvent can be controlled by the solvent used, solution concentration, film drying wind speed, drying temperature, time, drying room conditions (external air or internal air circulation), heating temperature of the back roller during coating, etc.

As mentioned above, the surface state can be controlled by increasing the drying rate to make the film thinner.

From the viewpoint of the curl balance of the film, the residual solvent amount S1 of the resin film for polarizing plates is preferably within a range of more than 10 ppm and less than 1000 ppm.

Furthermore, from the standpoint of improved film curl balance, the residual solvent content of the resin film for polarizing plates is preferably in the range of more than 100 ppm and less than 800 ppm, more preferably in the range of more than 500 ppm and less than 700 ppm. In addition, by selecting a solvent and coating procedure in which the solvent remains on the support, the adhesion between the support and the resin film for polarizing plates is improved. The residual solvent content of the support is preferably in the range of 10-100 ppm.

The amount of residual solvents in the support body and the resin film for polarizing plates can be measured by headspace gas chromatography. In headspace gas chromatography, the sample is sealed in a container, heated, and the container is filled with volatile components, and the gas in the container is quickly injected into the gas chromatograph for mass analysis to identify the compound. Volatile components were quantified. In the headspace method, the full peaks of volatile components can be observed by gas chromatography, and at the same time, the quantitative analysis of volatile substances or monomers can also be performed with high precision by using an analysis method that utilizes electromagnetic interaction. .

The cooling part B240 cools the temperature of the support body B110 having the coating film dried by the drying part B230, and adjusts it to an appropriate temperature. The cooling unit B240 has a cooling chamber B241, a cooling air inlet B242, and a cooling air outlet B243. The temperature and air volume of the cooling air can be appropriately determined according to the type of the coating film and the type of the support body B110. In addition, when the appropriate cooling temperature can be achieved without the cooling unit B240, the cooling unit B240 may not be provided.

The winding part B250 is a winding device (not shown) for winding the support body B110 formed with the resin film for polarizing plates to obtain the roll body B251.

≪3 Polarizer≫ The polarizing plate of the present invention is a polarizing plate having an adhesive layer and a polarizer layer on a resin film, and the resin film is characterized by comprising the resin film for polarizing plates of the present invention. The resin film is synonymous with the aforementioned protective layer, but preferably also has the function of a retardation film. Both sides of the polarizer layer can be protected by the polarizer resin film of the present invention, or one side can be protected by other known protective layers. In addition, the support system used when forming the resin film for polarizing plates may peel off, or may not peel off.

In FIG. 2, although one example is shown about the preferable layer structure of the polarizing plate of this invention, it is not limited to this example.

Fig. 2 is a cross-sectional view of the basic layer configuration of the polarizing plate of the present invention. The basic structure of the polarizing plate 10 of the present invention is that the polarizing plate resin film 1 of the present invention is bonded to the polarizer layer 3 through the adhesive layer 2 . On the surface of the polarizer 3 opposite to the surface of the polarizing plate resin film 1 of the present invention, a protective layer 4 can be pasted through the adhesive layer 2 if necessary. The protective layer system is not particularly limited, but the resin film for polarizing plates of the present invention can be used, and the retardation film described later can also be used.

The polarizing plate of the present invention suppresses movement of iodine contained in the polarizing sublayer by including the resin film for polarizing plates of the present invention. Therefore, the deterioration of the adhesion between the polarizer layer and the resin film for polarizing plates due to heat generation of the semiconductor substrate is suppressed, and contrast deterioration is suppressed in a display device including the polarizing plate of the present invention.

[3.1 Polarizer layer] The polarizer layer of the present invention is preferably a PVA iodine-dyed polarizer layer obtained by using a polyvinyl alcohol (PVA) film dyed with iodine. By using this polarizer layer, the effect of this invention can be expected. Furthermore, the so-called "polarizer" refers to an element that only passes light of a polarized wavefront in a certain direction. Hereinafter, although an example is shown about the preferable structure of the polarizer layer of this invention, it is not limited to this example.

Also, the thickness of the polarizer layer of the present invention is preferably in the range of 4-15 μm. Within the above range, the polarizing plate can be thinned.

[3.1.1 PVA iodine dyed polarizer layer] The thickness of the PVA film used for the PVA iodine-dyed polarizer layer before stretching is preferably 5 μm to 300 μm, particularly preferably 10 to 200 μm, from the viewpoint of stability of the film and uniformity of stretching. Also, as described in JP-A-2002-236212, a PVA film having a stress of 10 N or less can be used when stretching 4 to 6 times in water.

The stretched thickness of the PVA film is preferably within the range of 3-30 μm, more preferably within the range of 3-20 μm, and especially preferably within the range of 3-15 μm. Within the above range, the warpage or distortion of the liquid crystal panel caused by the ambient humidity can be reduced, and the display unevenness can be improved.

As the PVA film, it is preferably a polymer material after saponification of polyvinyl acetate, for example, it may also contain polyvinyl acetate copolymers such as unsaturated carboxylic acids, unsaturated sulfonic acids, olefins, and vinyl ethers. No matter the ingredients. Moreover, modified PVA containing an acetoacetyl group, a sulfonic acid group, a carboxyl group, an oxyalkylene group, etc. can also be used.

In addition, a PVA film having a 1,2-diol bonding amount of 1.5 mol% or less described in Japanese Patent No. 3021494, and an optical film having a thickness of 5 μm or more described in Japanese Patent Laid-Open No. 2001-316492 can be preferably used. The PVA film whose foreign matter is 500 or less per 100 cm ² , the PVA film whose hot water cut-off temperature variation in the TD direction of the film described in Japanese Patent Application Laid-Open No. A solution of 3-6 valent polyhydric alcohols such as glycerin or a PVA film made of a solution mixed with more than 15% by mass of a plasticizer described in Japanese Patent Application Laid-Open No. 06-289225.

The iodine to be dyed is preferably a high-order iodide ion such as I ₃ ^- or I ₅ ^- (polyiodide). High-order iodide ions can be as recorded in "Application of Polarizing Plates" Nagata Ryo, CMC Publishing or Industrial Materials, Vol. / Or immerse the PVA film in the boric acid aqueous solution to form in the state of adsorption and alignment on the PVA film.

Relative to the total mass of the polarizer layer, the content of iodine is preferably within the range of 1.8-5.0% by mass, more preferably within the range of 2.0-4.0% by mass. By obtaining a polarizing plate with a desired transmittance within the above range, a liquid crystal display device with high contrast in the front direction can be obtained.

The polarizer layer preferably contains boric acid as a crosslinking agent. By cross-linking with boric acid, the stability of the complex formed by iodine and PVA is improved, which can inhibit the deterioration of the polarizing performance under high temperature and high humidity conditions.

The content of boric acid is calculated as boron, and relative to the total mass of the polarizer layer, it is preferably within the range of 0.5-3.0% by mass, more preferably within the range of 1.0-2.8% by mass, and most preferably within the range of 1.5-2.6% by mass. within range.

The dichroic ratio DR of the polarizer layer is preferably above 160, more preferably within the range of 160-220, especially preferably within the range of 170-210, and particularly preferably within the range of 175-185. Within the above range, a liquid crystal panel and a liquid crystal display device having a high front contrast and having a polarizing plate of the present invention are obtained. Such a liquid crystal panel and a liquid crystal display device are suitable for television use, for example. In addition, the dichromatic ratio DR is calculated|required by the following formula. Two-color ratio DR=log(0.919/k2)/log(0.919/k1) Here, k1 is the transmittance in the direction of the transmission axis of the polarizer layer, k2 is the transmittance in the direction of the absorption axis of the polarizer layer, and the constant 0.919 is the interface reflectance.

The transmittance (single substance transmittance) Ts of the polarizer layer is preferably at least 42%, more preferably in the range of 42.0-44.0%, and most preferably in the range of 42.5-43.0%. Within the above range, a high-brightness liquid crystal panel or liquid crystal display device including the polarizing plate of the present invention can be obtained. Such a liquid crystal panel and a liquid crystal display device are suitable for television use, for example. Also, the transmittance of the polarizing plate can be obtained from the following formula. Penetration rate (%)={(k1+k2)/2}×100 Here, k1 is the transmittance in the direction of the transmission axis of the polarizer layer, and k2 is the transmittance in the direction of the absorption axis of the polarizer layer.

The linear expansion coefficient of the polarizer layer in the direction of the transmission axis is not particularly limited, and is preferably in the range of 4.0×10 ^-5 ~5.0×10 ^-5 /°C.

[Manufacturing method] The manufacturing method of the PVA iodine-dyed polarizer layer used in the present invention is not particularly limited, but for example, it is preferably manufactured by introducing iodine into the PVA after thinning the above-mentioned PVA. The PVA film can refer to paragraphs 0213~0237 of Japanese Patent Application Publication No. 2007-86748, Japanese Patent Application Publication No. 3342516, Japanese Patent Application Publication No. 09-328593, Japanese Patent Application Publication No. 2001-302817, and Japanese Patent Application Publication No. 2002-144401. Manufactured by the method described in the gazette, etc.

As a method for producing the PVA iodine-dyed polarizing layer, for example, a method of sequentially performing a preparation step of a PVA solution, a casting step, a swelling step, a dyeing step, a dura mater step, an extending step, and a drying step is preferable. In addition, during or after the above-mentioned journey, a step of checking the shape on the line can also be provided.

(Preparation of PVA solution) In the step of preparing the PVA solution, it is preferable to prepare a stock solution in which PVA is dissolved in water or an organic solvent. The concentration of PVA in the stock solution is preferably in the range of 5-20% by mass. For example, it is preferable to put the wet cake of PVA into the dissolving tank, add plasticizer and water if necessary, and stir while blowing water vapor from the bottom of the tank. The internal resin temperature is preferably heated to a range of 50~150°C, and the system can also be pressurized.

(casting) The casting step is preferably a method of casting the PVA solution prepared above to form a film. As the method of casting, there is no special limitation, but it is preferred to supply the heated PVA solution stock solution to the twin-screw extruder, and discharge it from the discharge means (preferably a die head, more preferably T-shaped) by a gear pump. slot die) onto a support to form a film. Also, the temperature of the PVA solution discharged from the die is not particularly limited. As the above-mentioned support body, a casting drum is preferred, and the diameter, width, rotation speed and surface temperature of the drum are not particularly limited. Then, drying is preferably carried out while passing the back surface and the surface of the obtained roll alternately through drying rolls.

(swelling) The swelling step is preferably carried out only with water, but as described in Japanese Patent Application Laid-Open No. 10-153709, in order to stabilize the optical properties and avoid wrinkles of the PVA film in the production line, the PVA film can also be swollen by boric acid aqueous solution, Manage swelling of PVA film. Also, the temperature and time of the swelling step can be specified arbitrarily, but are preferably within the range of 10-60°C and within the range of 5-2000 seconds. Furthermore, it is also possible to slightly extend during the swelling step, for example, it is preferable to extend to about 1.3 times.

(dyeing) For the dyeing step, the method described in JP 2002-86554 A can be used. In addition, as a dyeing method, not only immersion, but also arbitrary means such as application or spraying of iodine may be used. In addition, as described in Japanese Patent Application Laid-Open No. 2001-296427, the concentration of iodine, the temperature of the dyeing bath, and the stretching ratio in the bath are set at appropriate values, and the bath liquid in the bath is dyed while stirring, so that the polarizer layer can be obtained. Polarizing plate with high light transmittance and high polarizing rate.

When high-order iodide ions are used, in order to obtain a high-contrast polarizing plate, the dyeing step preferably uses a solution in which iodine is dissolved in an aqueous potassium iodide solution. In this case, the mass ratio of iodine to potassium iodide in the iodine-potassium iodide aqueous solution can use the form described in JP-A-2007-086748. Also, as described in Japanese Patent No. 3145747, boron compounds such as boric acid and borax may be added to the dyeing solution.

(dural) In the hard coat step, it is preferable to immerse or coat the solution in a crosslinking agent solution so as to contain the crosslinking agent. Also, as described in JP-A-11-52130, the dura mater step may be divided into several times.

As the crosslinking agent, those described in US Reissued Patent No. 232897 can be used, and as described in Japanese Patent No. 3357109, in order to improve dimensional stability, polyvalent aldehydes can also be used, but boric acids are preferably used. When boric acid is used as the cross-linking agent for the hard coating step, metal ions can be added to the boric acid-potassium iodide aqueous solution. As the metal ion, zinc chloride is preferable, and as described in JP-A-2000-35512, instead of zinc chloride, zinc halides such as zinc iodide, zinc sulfate, zinc acetate and other zinc salts can also be used.

In addition, it is also possible to prepare a boric acid-potassium iodide aqueous solution containing zinc chloride, and dip a PVA film to form a hard film, and the method described in JP 2007-086748 A can be used.

In addition, here, as a method of improving durability in a high-temperature environment, a well-known dipping treatment in an acidic solution may be performed. Examples of the treatment of the acidic solution include methods described in JP-A-2001-83329, JP-A-6-254958, and International Publication WO2006/095815.

(extend) For the stretching step, the longitudinal uniaxial stretching method described in US Patent No. 2,454,515 or the tenter method described in Japanese Patent Application Laid-Open No. 2002-86554 can be preferably used. The preferred extension ratio is in the range of 2-12 times, more preferably in the range of 3-10 times.

In addition, the relationship between the elongation ratio, the thickness of the original material and the thickness of the polarizer layer is as described in Japanese Patent Application Laid-Open No. 2002-040256 (the thickness of the polarizer film after the protective film is pasted/the thickness of the original material) × (total elongation magnification) > 0.17, the relationship between the width of the polarizer layer when leaving the final bath and the width of the polarizer layer when the protective film is pasted is 0.80≦(when the protective film is pasted The width of the polarizer layer/the width of the polarizer when leaving the final bath)≦0.95 can also be carried out better. Also, the so-called protective film here is synonymous with the protective layer in the present invention.

(dry) For the drying step, a well-known method described in JP-A-2002-86554 can be used, but the preferred temperature is within the range of 30 to 100° C., and the preferred drying time is within the range of 30 seconds to 60 minutes. Also, it is preferable to carry out a heat treatment such as a temperature of 50° C. or higher for discoloration in water as described in Japanese Patent No. 3148513, or as described in Japanese Patent Application Publication No. 07-325215 or Japanese Patent Application Publication No. 07-325218. Aged in a temperature and humidity controlled environment.

Through the above-mentioned steps, it is preferable to manufacture so that the thickness of the polarizer layer may be in the range of 4 to 15 μm. Furthermore, the thickness can be controlled by a well-known method, for example, by setting the slit width or stretching conditions in the above-mentioned casting step to appropriate values.

[3.2 Adhesive layer] The polarizing plate of the present invention is obtained by laminating protective layers on both sides of the obtained polarizer layer through an adhesive layer. Both sides of the polarizer layer can be protected by the polarizer resin film of the present invention, and one side can also be protected by other known protective layers.

The adhesive layer of the present invention is formed by an adhesive. As an adhesive agent, an isocyanate type adhesive agent, a polyvinyl alcohol type adhesive agent, a gelatin type adhesive agent, vinyl latex type, water-type polyester etc. are mentioned, for example. These adhesives are usually used as adhesives (water-based adhesives) formed from aqueous solutions, and the solid content concentration of the adhesives in the aqueous solution is preferably in the range of 0.5 to 60% by mass. Among them, a polyvinyl alcohol-based adhesive is preferable, and an acetoacetyl group-containing polyvinyl alcohol-based adhesive is more preferable.

The water-based adhesive may contain a crosslinking agent. As a crosslinking agent, a compound having at least two functional groups reactive with components such as a polymer constituting the adhesive in one molecule is usually used, for example, alkyl diamines; isocyanates; epoxy ; Aldehydes; methylol urea, methylol melamine and other amino-formaldehyde. The content of the crosslinking agent in the adhesive is preferably within a range of 10 to 60% by mass relative to the components such as the polymer constituting the adhesive.

Examples of the adhesive include active energy ray-curable adhesives such as ultraviolet-curable adhesives and electron beam-curable adhesives, in addition to the above. As said active energy ray hardening type adhesive agent, a (meth)acrylate type adhesive agent is mentioned, for example. As a curable component in the said (meth)acrylate adhesive agent, the compound which has a (meth)acryl group, the compound which has a vinyl group is mentioned, for example. Examples of compounds having a (meth)acryl group include chain alkyl (meth)acrylates having 1 to 20 carbon atoms, alicyclic alkyl (meth)acrylates, poly(meth)acrylates, etc. Alkyl (meth)acrylates such as cyclic alkyl esters; hydroxyl-containing (meth)acrylates; epoxy-group-containing (meth)acrylates such as glycidyl (meth)acrylate, etc. (Meth) acrylate-based adhesives can include hydroxyethyl (meth) acrylamide, N-methylol (meth) acrylamide, N-methoxymethyl (meth) acrylamide, Nitrogen-containing monomers such as N-ethoxymethyl(meth)acrylamide, (meth)acrylamide, (meth)acrylylmorpholine, etc. (Meth)acrylate adhesives can include tripropylene glycol diacrylate, 1,9-nonanediol diacrylate, tricyclodecane dimethanol diacrylate, cyclic trimethylolpropane formal acrylate, Dioxanediol diacrylate, EO modified diglycerol tetraacrylate and other multifunctional monomers are used as crosslinking components. Moreover, the compound which has an epoxy group or an oxetanyl group can also be used as a cationic polymerization hardening type adhesive agent. 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.

The above-mentioned adhesive system may contain appropriate additives as necessary. Examples of additives include coupling agents such as silane coupling agents and titanium coupling agents, adhesion promoters such as ethylene oxide, ultraviolet absorbers, anti-deterioration agents, dyes, processing aids, ion scavengers, antioxidants, Tackifier, filler, plasticizer, leveling agent, foam inhibitor, antistatic agent, heat-resistant stabilizer, hydrolysis-resistant stabilizer, etc.

The application of the adhesive agent may be performed on either the protective layer side or the polarizer layer side, or both. After bonding, a drying step is applied to form an adhesive layer formed by coating a dry layer. After the adhesive drying step, ultraviolet rays or electron rays may be irradiated if necessary.

The bonding method of the protective layer and the polarizer layer is preferably such that the transmission axis of the polarizer layer is substantially parallel to the slow axis of the protective layer. Here, the term “substantially parallel” means that the deviation between the direction of the main refractive index n _x of the protective layer and the direction of the transmission axis of the polarizer layer is within 5°. The offset is preferably within 1°, more preferably within 0.5°. As long as the deviation is within 1°, the polarizing performance of the polarizing plate under crossed Nicols is unlikely to decrease, and light leakage is unlikely to occur.

The thickness of the adhesive layer of the present invention is not particularly limited, but in the case of using a water-based adhesive or the like, it is preferably in the range of 30 to 5000 nm, more preferably in the range of 100 to 1000 nm. When using ultraviolet curable adhesives, electron beam curable adhesives, etc., it is preferably in the range of 0.1 to 100 μm, more preferably in the range of 0.5 to 10 μm.

[3.3 Protection layer] As the protective layer 4 shown in Figure 2, in addition to the resin film for polarizing plates of the present invention can be used suitably, a known protective layer can be used, such as cellulose acylate film, polyester film (such as polyparaphenylene Diformic acid ethylene glycol film, etc.), cycloolefin resin film, acrylic resin film, etc.

Examples of commercially available cellulose acylate films include Konica Minolta TAC KC8UX, KC5UX, KC4UX, KC8UCR3, KC4SR, KC4BR, KC4CR, KC4DR, KC4FR, KC4KR, KC8UY, and KC6UY manufactured by Konica Minolta Advanced Layer Co., Ltd. , KC4UY, KC4UE, KC8UE, KC8UY-HA, KC2UA, KC4UA, KC6UA, KC2UAH, KC4UAH, KC6UAH, etc.

The thickness of the protective layer is not particularly limited, but is preferably within the range of 1-100 μm, more preferably within the range of 3-40 μm, and most preferably within the range of 5-20 μm.

≪4 Display device≫ The display device of the present invention suppresses contrast deterioration by including the polarizing plate of the present invention.

The display device of the present invention is obtained, for example, by attaching the polarizing plate of the present invention to the surface of the display device through an adhesive layer or an adhesive layer. The so-called display device refers to a device with a display mechanism, including a light emitting element or a light emitting device as a light source.

Examples of display devices include liquid crystal display devices, organic electroluminescence (EL) display devices, inorganic electroluminescence (EL) display devices, touch panel display devices, electron emission display devices (field emission display devices (FED, etc.) , surface electric field emission display device (SED)), electronic paper (display device using electronic ink or electrophoretic moving element), plasma display device, projection display device (display device with gate light valve (GLV), digital micromirror device (DMD) display devices, etc.) and piezoelectric ceramic displays, etc.

The above-mentioned liquid crystal display device includes any one of a transmissive liquid crystal display device, a semi-transmissive liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection type liquid crystal display device. These display devices may be display devices that display 2D images, or may be stereoscopic display devices that display 3D images. In particular, as the display device of the present invention, an organic EL display device and a touch panel display device are preferable, and an organic EL display device is particularly preferable. [Example]

Hereinafter, although an Example is given and this invention is demonstrated concretely, this invention is not limited to these. In addition, the expression of "part" or "%" is used in an Example, and unless otherwise specified, it represents "part by mass" or "% by mass", respectively.

Example 1 [1] Manufacture of resin film for polarizing plate

＜Preparation of resin film 1 for polarizing plate＞ (support body) As a support, a polyethylene terephthalate film (PET film): (TN100 manufactured by Toyobo Co., Ltd., release layer containing a non-silicone release agent, film thickness 38 μm) was used.

(Preparation of solution for resin film 1 for polarizing plates) The following components were mixed to obtain a solution for resin film 1 for polarizing plates. Dichloromethane (boiling point: 41°C) 860 parts by mass Methanol (boiling point: 65°C) 40 parts by mass 100 parts by mass of metal oxide particles: Al ₂ O ₃ (SA43A: manufactured by Nippon Light Metal Co., Ltd.) 20 parts by mass of antioxidant (Irganox (registered trademark) 1076: manufactured by BASF Corporation: molecular weight 531) added to the resin film for polarizing plates When the addition amount was 0.002% by mass, the metal oxide was put into a mixed solvent (50:50) of methylene chloride and methanol, and the dispersion treatment with a Manton Gaulin homogenizer was performed three times. Then, it was charged into a dissolution tank into which dichloromethane was charged and stirred, and the resin was further charged and stirred to obtain a solution for a resin film 1 for a polarizing plate.

(Production of resin film 1 for polarizing plate) On the release layer of the above-mentioned support body, the solution for resin film 1 for polarizing plates was coated with a die head by the back coating method, and then the following drying process was performed to form a resin film for polarizing plates with a thickness of 6 μm to obtain polarized light. Resin film 1 for board. Step 1: 1 minute at 40°C Step 2: 1 minute at 70°C Step 3: 1 minute at 100°C Step 4: 2 minutes at 130°C

The thickness of the prepared resin film for polarizing plates was measured using F20-UV (manufactured by FILMETRICS) as a film thickness measuring system.

Also, the thermal conductivity of the film is sandwiched between the TO-3 type heating box and the copper plate, compressing 10% of the thickness of the film. Next, 5W of electric power was applied to the copper heating box and kept for 4 minutes, and the temperature difference between the copper heating box and the copper plate was measured. The thermal conductivity was calculated by the following formula. Thermal conductivity {W/m･K}={power (W)×thickness (m)}/{temperature difference (K)×measurement area (m ² )}

The value of the ratio of the average primary particle diameter to the average secondary particle diameter (particle diameter ratio) shown by the average secondary particle diameter/average primary particle diameter of metal oxide particles is calculated using the average particle diameter obtained by the following method figured out. In the sample prepared by the ultrathin section method, observe the primary particle (or secondary particle) with a transmission electron microscope (H-7100FA manufactured by Hitachi), and assume the diameter of a circle equal to the projected area (the so-called circle equivalent diameter) as the primary particle size (or secondary particle size). Then, the particle diameters of 1000 primary particles (or secondary particles) obtained in this way were averaged, and the average value was regarded as the average primary particle diameter (or average secondary particle diameter).

<Preparation of resin films 2, 12, and 13 for polarizing plates> Except that the metal oxide particles were changed to ZnO (FINEX (registered trademark) 50: manufactured by Sakai Chemical Industry Co., Ltd.), CuO (FCO500: Except for Furukawa Chemical Co., Ltd.) and TiO ₂ (STR (registered trademark) 100N: Sakai Chemical Industry Co., Ltd.), the resin films 2 and 12 for polarizing plates were produced in the same manner as the resin film 1 for polarizing plates. and 13.

＜Preparation of resin film 3 for polarizing plate＞ Except having changed the solution for the resin film for polarizing plates into the following, it carried out similarly to preparation of the resin film 1 for polarizing plates, and produced the resin film 3 for polarizing plates.

(modulation of rubber particles R1) Rubber particles R1 prepared by the following method were used. In the 8L polymerization device with agitator, add the following substances. Deionized water 180 parts by mass Polyoxyethylene lauryl ether phosphoric acid 0.002 parts by mass Boric acid 0.473 parts by mass Sodium carbonate 0.047 parts by mass Sodium hydroxide 0.008 parts by mass

After fully substituting the inside of the polymerizer with nitrogen, the internal temperature was set to 80° C., and 0.021 parts by mass of potassium persulfate was added as a 2% aqueous solution. Next, in a monomer mixture composed of 84.6% by mass of methyl methacrylate, 5.9% by mass of butyl acrylate, 7.9% by mass of styrene, 0.5% by mass of allyl methacrylate, and 1.1% by mass of n-octyl mercaptan (c') 0.07 mass part of polyoxyethylene lauryl ether phosphoric acid was added to 21 mass parts, and the obtained liquid mixture was continuously added to the said solution over 63 minutes. Furthermore, by continuing the polymerization reaction for 60 minutes, the innermost hard polymer (c) was obtained.

Then, 0.021 parts by mass of sodium hydroxide was added as a 2% by mass aqueous solution, and 0.062 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution. Next, 0.25% polyoxyethylene lauryl ether phosphoric acid was added to 39 parts by mass of a monomer mixture (a') consisting of 80.0% by mass of butyl acrylate, 18.5% by mass of styrene, and 1.5% by mass of allyl methacrylate. The obtained mixed solution was added continuously for 117 minutes in parts by mass. After completion of the addition, 0.012 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution, and the polymerization reaction was continued for 120 minutes to obtain a soft layer (a layer made of an acrylic rubber-like polymer (a)).

Then, 0.04 parts by mass of potassium persulfate was added as a 2% by mass aqueous solution, and 26.1 parts by mass of a monomer mixture (b') consisting of 97.5% by mass of methyl methacrylate and 2.5% by mass of butyl acrylate was continuously added over 78 minutes. . Furthermore, the polymerization reaction was continued for 30 minutes to obtain a polymer (b).

The obtained polymer was put into a warm aqueous solution of 3% by mass sodium sulfate, and salted out and coagulated. Next, after repeated dehydration and washing, it was dried to obtain acrylic graft copolymer particles (rubber particles R1) with a three-layer structure. The average particle diameter of the obtained rubber particles R1 was 200 nm.

The average particle diameter of the rubber particles was measured by the following method. The dispersed particle diameter of the rubber particles in the obtained dispersion liquid was measured with a zeta potential and particle diameter measuring system (ELSZ-2000ZS manufactured by Otsuka Electronics Co., Ltd.).

(Preparation of solution for resin film 3 for polarizing plates) The following components were mixed to obtain solution 5 for resin films for polarizing plates. Dichloromethane (boiling point 41° C.) 800 parts by mass Acrylic acid: MMA/PMI/MADA copolymer (60/20/20 mass ratio), Mw: 1.5 million, Tg: 137° C. (Also, abbreviated as follows. MMA: methyl Methyl acrylate, PMI: phenylmaleimide and MADA: adamantyl acrylate) 80 parts by mass of rubber particles R1 20 parts by mass of metal oxide particles: Al ₂ O ₃ (SA43A: manufactured by Nippon Light Metal Co., Ltd.) 20 Parts by mass of dispersant (sodium polyoxyethylene lauryl ether phosphate: molecular weight 332) is added in an amount of 0.006% by mass to the resin film for polarizing plates

＜Production of resin films 4~6 and 11 for polarizing plates＞ Except for changing the thickness of the resin film for polarizing plates to the thickness described in Table 1, the resin films for polarizing plates 4 to 6 and 11 were produced in the same manner as the production of resin film 1 for polarizing plates.

＜Production of resin films for polarizing plates 7~10＞ Resin films 7 to 10 for polarizing plates were produced in the same manner as the production of resin film 1 for polarizing plates, except for changing the number of times of processing by the Menton Collin homogenizer and changing the particle size ratio of the metal oxide particles.

＜Production of resin films 14~16 for polarizing plates＞ The resin film 14 for a polarizing plate was produced in the same manner as the production of the resin film 1 for a polarizing plate except that 5 parts by mass of Compound 1 shown below and 0.005 parts by mass of sulfuric acid were used instead of the metal oxide particles. Moreover, the thickness of the resin film for polarizing plates was changed to the thickness described in Table II, and the resin films 15 and 16 for polarizing plates were produced.

＜Manufacture of resin films for polarizing plates 17~20＞ Resin films 18 to 20 for polarizing plates were produced in the same manner as the production of resin film 14 for polarizing plates, except that the content of sulfuric acid ions was changed to the content described in Table II. In addition, sulfuric acid was not added to the resin film 17 for polarizing plates.

<Production of resin film 21 for polarizing plate> The resin film 21 for a polarizing plate was produced in the same manner as the production of the resin film 14 for a polarizing plate except that the addition amount of the compound 1 and the content of the sulfate ion were changed to those described in Table II.

<Production of resin film 22 for polarizing plate> The resin film 22 for a polarizing plate was produced in the same manner as the production of the resin film 3 for a polarizing plate except that 5 parts by mass of Compound 1 shown below was used instead of the metal oxide particles.

＜Production of resin films 23~32 and 34~36 for polarizing plates＞ Resin films 23 to 32 and 34 to 36 for polarizing plates were produced in the same manner as the production of resin film 14 for polarizing plates except that compound 1 was changed to the compounds shown below.

<Production of resin film 33 for polarizing plate> A polarizing plate resin film 33 was fabricated in the same manner as the polarizing plate resin film 14 except that compound 1 was changed to the following compound 7 and the thickness of the polarizing plate resin film was changed to 20 μm.

The structural formulas of the organic compounds used (commercially available products and our company's synthetic products synthesized by well-known methods) are shown below. As the compound 6, (18-crown 6-ether) manufactured by Tokyo Chemical Industry Co., Ltd. was used as the commercially available product, and acetic acid manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. was used as the compound 10. Synthesis by our company is carried out with reference to, for example, the method described in paragraph 0083 of Japanese Patent No. 5919227.

Compounds 1-9 and 13-14 function as iodine mobilization inhibitors. Also, Compound 10 does not satisfy the definition of the non-organic acid of the present invention, and does not function as an iodine transfer inhibitor. Compounds 11 and 12 were outside the range of 5 to 9 MPa ^0.5 in δP (polar force) of the HSP value, and did not function as iodine migration inhibitors.

The HSP value (δP and δD) of each compound described in Table II is the calculated value of HSPiP 5th edition.

In addition, the content of sulfate ions relative to the total solid mass of the resin film for polarizing plates was measured with a capillary electrophoresis device. In addition, the conditions of capillary electrophoresis are as follows. Capillary electrophoresis device: CAPI-3100 (manufactured by Otsuka Electronics Co., Ltd.) Capillary: Fused silica capillary with unmodified inner surface (manufactured by GL Sciences, inner diameter 50 μm, length 62.5 cm, effective length 50 cm) Sample injection: drop method (2.5cmx30 seconds) Applied voltage: 25kV Detection wavelength: 200nm Swimming solution: 50mM boric acid buffer (pH10.5)

[2] Production of polarizer layer ＜Fabrication of polarizer layer (3μm)＞ A polyvinyl alcohol-based film with a thickness of 20 μm was swelled with water at 35° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and further immersed in a 45° C. aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. The obtained film was uniaxially stretched at a stretching temperature of 55° C. and a stretching ratio of 5 times. After the uniaxially stretched film was washed with water, it was dried to form a polarizer layer with a thickness of 3 μm.

＜Fabrication of polarizer layer (7μm)＞ A polyvinyl alcohol-based film with a thickness of 40 μm was swelled with water at 35° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and further immersed in a 45° C. aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. The obtained film was uniaxially stretched at a stretching temperature of 55° C. and a stretching ratio of 5 times. After the uniaxially stretched film was washed with water, it was dried to form a polarizer layer with a thickness of 7 μm.

＜Fabrication of polarizer layer (13μm)＞ A polyvinyl alcohol-based film with a thickness of 60 μm was swelled with water at 35° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and further immersed in a 45° C. aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. The obtained film was uniaxially stretched at a stretching temperature of 55° C. and a stretching ratio of 5 times. After the uniaxially stretched film was washed with water, it was dried to form a polarizer layer with a thickness of 13 μm.

＜Fabrication of polarizer layer (20μm)＞ A polyvinyl alcohol-based film with a thickness of 100 μm was swelled with water at 35° C. The obtained film was immersed in an aqueous solution consisting of 0.075 g of iodine, 5 g of potassium iodide, and 100 g of water for 60 seconds, and further immersed in a 45° C. aqueous solution of 3 g of potassium iodide, 7.5 g of boric acid, and 100 g of water. The obtained film was uniaxially stretched at a stretching temperature of 55° C. and a stretching ratio of 5 times. After the uniaxially stretched film was washed with water, it was dried to form a polarizer layer with a thickness of 20 μm.

[3] Production of polarizing plate On the resin films 1-36 for polarizing plates, the following water-soluble adhesive solutions were passed through, respectively, and the polarizer layer (7 μm) and the protective layer were bonded to produce polarizing plates 1-29. Regarding the resin film 1 for polarizing plates, polarizing plates 1-1, 1-2, 1-3, and 1-4 each having polarizing sublayers with a thickness of 7, 3, 13, and 20 μm bonded thereto were produced. Similarly, with respect to the resin film 14 for polarizing plates, polarizing plates 14-1, 14-2, and 14-3 in which polarizing sub-layers having a thickness of 7, 3, and 20 μm were bonded were produced, respectively.

(Preparation of water-soluble adhesive solution) After mixing the following components, defoaming was performed to prepare a water-soluble adhesive solution. Pure water 100 parts by mass "Epocros WS-300" manufactured by Nippon Shokubai Co., Ltd. 7.5 parts by mass "CROSSLINKER CL-427" made by MENADIONA 0.1 parts by mass

Moreover, the production of polarizing plates is to apply corona discharge treatment to the adhesive side surface of the resin film for polarizing plates with a corona output intensity of 2.0kW and a line speed of 18m/min, and to coat the corona discharge treated surface with a bar coater. The water-soluble adhesive solution prepared above was dried to a thickness of about 3 μm after drying, and then dried at 50° C., 60° C., and 70° C. for 60 seconds in order, and then bonded. Similarly, KC2CT-W (manufactured by Konica-Minolta Co., Ltd.) was bonded to the surface of the polarizer layer on which the polarizing plate resin film was not bonded, and the support of the polarizing plate resin film was peeled off to obtain polarizing plates 1 to 36.

≪Evaluation≫ The obtained polarizing plate was incorporated into a display device, and the backlight was continuously turned on for 1 week in an environment of 80°C･55%RH. After that, a part of the polarizing plate was removed, and the following adhesion evaluation was performed. Moreover, the following comparative evaluation was performed about the remaining polarizing plate parts.

(1) Positive comparative evaluation Using the device "CS-2000" manufactured by Konica Minolta Sensing Co., Ltd., light with a wavelength of 550 nm was irradiated, and the brightness of the white display state and the black display state of the liquid crystal display device were measured from the normal direction of the display screen of each liquid crystal display device. Then, the obtained value was applied to the following formula, and the front contrast (CR) was computed. Front contrast (CR)=(brightness of white display state)-(brightness of black display state)

The value of the frontal comparison after continuous lighting for 1 week was evaluated based on the following criteria. Also after the lighting treatment, whether or not the front CR was similarly expressed was evaluated by the following criteria, and △ or more was regarded as good. ◎: 900≦CR 〇: 850≦CR<900 △: 800≦CR<850 ×: 800>CR

(2) Adhesion evaluation The obtained sample was subjected to a peeling test at a peeling speed of 300 mm/min in a direction of 180° at the interface between the resin film for a polarizing plate and the polarizer layer. The peel strength (adhesive force) [N/25mm] at this time was measured using "Autograph AGS-50NX" manufactured by Shimadzu Corporation. Then the value of the force is to make 3 samples (N number = 3), and the average value of the 3 values is used. Also, although the peeling between the resin film for polarizing plates and the polarizer layer occurs at either the interface between the resin film for polarizing plates and the adhesive layer or the interface between the polarizer layer and the adhesive layer, in this evaluation , the peeling state was visually observed, and the peeling strength when peeling occurred at the interface between the resin film for polarizing plates and the adhesive layer was adopted. The value of adhesive force was evaluated according to the following criteria. After the lighting treatment, it was evaluated whether or not the adhesive force was similarly exhibited by the following criteria, and △ or more was regarded as good. ◎: The film material will be damaged, and the adhesive force cannot be measured 〇: Adhesion force exceeds 2.0N/25mm △: Adhesive force within the range of 1.0~2.0N/25mm ×: Adhesion force is less than 1.0N/25mm

The evaluation results are shown in Table I and Table II below.

From the above results, it can be seen that the polarizing plate provided with the resin film for polarizing plates of the present invention suppresses the decrease in adhesive force and the deterioration in contrast due to heat generation of the semiconductor substrate. [industrial availability]

By using the resin film for polarizing plates of the present invention as a polarizing plate in a display device, it is possible to suppress the decrease in adhesive force and the deterioration of contrast due to heat generation of the semiconductor substrate, so that it is possible to suppress the effects of the 5th generation mobile communication system (5G). ) The durability of communication equipment due to heat is reduced.

B110: Support body B200: Manufacturing Devices B210: Supply Department B220: Coating Department B230: Drying section B240: Cooling section B250: Coiler 1: Resin film for polarizing plate 2: Adhesive layer 3: polarizer layer 4: Protective layer 10: polarizer

[FIG. 1] It is a model diagram of the manufacturing apparatus B200 for implementing the manufacturing method of the resin film for polarizing plates of this invention. [ Fig. 2 ] is a cross-sectional view of the basic layer structure of the polarizing plate of the present invention.

1: Resin film for polarizing plate

2: Adhesive layer

3: polarizer layer

4: Protective layer

10: polarizer

Claims (11)

A resin film for a polarizing plate, which is at least used for a polarizing plate with a polarizing sub-layer containing iodine, characterized in that: Contains at least a thermoplastic resin and an iodine migration inhibitor, The film thickness is 1 μm or more and less than 15 μm. Such as the resin film for polarizing plates of claim 1, wherein The aforementioned iodine movement inhibitor is a metal oxide particle, The thermal conductivity of the aforementioned resin film for polarizing plates is within the range of 0.2 to 0.6 W/m･K. The resin film for polarizing plates as claimed in claim 2, wherein the ratio of the average primary particle size to the average secondary particle size of the aforementioned metal oxide particles satisfies the following formula (1); Formula (1): 20<average secondary particle size/average primary particle size<2000. Such as the resin film for polarizing plates of claim 1, wherein the aforementioned iodine transfer inhibitor is a non-organic acid, and the δP (polar force) of the Hansen (Hansen) solubility parameter (HSP value) of the aforementioned non-organic acid is 5 ~ 9MPa ^0.5 within the range. Such as the resin film for polarizing plates of claim 4, wherein The value of the ratio of δD (dispersion force) and δP (polar force) of the aforementioned HSP value of the aforementioned non-organic acid satisfies the following formula (2); Formula (2): 2<δD (dispersion force)/δP (polar force)<4. The resin film for polarizing plates as claimed in item 4 or 5, wherein The aforementioned iodine movement inhibitor further contains sulfate ions, and Content of the said sulfate ion exists in the range of 1-100 mass ppm with respect to the solid content gross mass of the resin film for polarizing plates. The resin film for polarizing plates according to any one of claims 1 to 6, wherein the thermoplastic resin is a cycloolefin resin. A method for manufacturing a resin film for a polarizing plate, which is a method for manufacturing a resin film for a polarizing plate according to any one of claims 1 to 7, characterized in that it has: A step of coating a solution containing a thermoplastic resin and an iodine migration inhibitor on the release layer using a resin film having a release layer as a support. A polarizing plate, which is a polarizing plate with an adhesive layer and a polarizer layer on a resin film, characterized by: As said resin film, the resin film for polarizing plates in any one of Claims 1-7 is provided. The polarizing plate according to claim 9, wherein the thickness of the aforementioned polarizing sub-layer is within the range of 4 to 15 μm. A display device, which is a display device equipped with a polarizing plate, is characterized in that: As the polarizing plate, the polarizing plate according to claim 9 or 10 is provided.

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