TWI795500B - Stack for polarizing plate, polarizing plate, stacked film roll, method for manufacturing stack for polarizing plate, and method for manufacturing polarizing plate - Google Patents

Abstract

A stacked body for polarizing plates, comprising: a polyvinyl alcohol resin film having a light transmittance of 550 nm at a wavelength of 50% or more, and a resin layer directly stacked on at least one side of the polyvinyl alcohol resin film. The aforementioned resin layer is preferably a laminate formed by coating the aforementioned polyvinyl alcohol resin film with a resin. Also disclosed are a method for manufacturing a stack for polarizing plates, a polarizing plate manufactured using a stack of polarizing plates, a stacked film roll, and a method for manufacturing polarizing plates.

Description

Stack for polarizing plate, polarizing plate, stacked film roll, method for manufacturing stack for polarizing plate, and method for manufacturing polarizing plate

The present invention relates to a stack for polarizing plates, a polarizing plate, a stack film roll, a method for manufacturing a stack for polarizing plates, and a method for manufacturing a polarizing plate.

Display devices such as liquid crystal display devices and organic electroluminescent (EL) display devices have conventionally been required to have a large display area, light weight, and thin thickness. Therefore, panels constituting display devices have also been required to be thinner in the past.

In a display device, a polarizing plate provided with a polarizer and a protective film for protecting the polarizer is generally used. In order to form a thin display device, the polarizing plate is also required to be thinner. In particular, since the polarizer sometimes shrinks in the use environment of the display device, in a thin and large-area display device, bending caused by such shrinkage may become a problem. Therefore, by using a thin polarizer with a thickness of 10 μm or less, in addition to the reduction in the thickness of the display device due to the reduction in the thickness of the polarizer itself, the reduction in the occurrence of warping as described above can also be expected.

However, when such a thin polyvinyl alcohol polarizer is to be manufactured by the conventional manufacturing method, melting of the polarizer frequently occurs. Several methods have been proposed as a method of manufacturing such a polarizing plate that "prevents melting of the polarizer and includes a thin polarizer".

For example, in Patent Document 1, it has been proposed to apply an aqueous solution containing a polyvinyl alcohol-based resin to a resin film made of an amorphous ester-based thermoplastic resin, thereby manufacturing a polyvinyl alcohol-based resin layer to form a laminate, and After stretching the stacked body, orienting the dichroic substance to make a colored stacked body, and then stretching the colored stacked body to obtain an optical film.

"Patent Documents" "Patent Document 1": Japanese Patent No. 4691205 (corresponding publication: US Patent No. 8314987 specification)

In the case of manufacturing a thin polarizing plate by the method described in Patent Document 1, a retardation may occur in the stretched resin film due to stretching the stacked body at a high stretching ratio. In such a case, since it is difficult to use the resin film as it is as a polarizing plate protective film, it must be peeled off and discarded, resulting in wasteful material. Furthermore, the work of additionally preparing a protective film for protecting the polarizing plate and affixing it to the polarizing plate may be added.

Therefore, an object of the present invention is to provide a laminate for polarizing plates that can be used as a protective film even if a resin film (resin layer) is used as a protective film, and can be efficiently produced even if it is thin, and a method for producing the same, and a product using the laminate. A polarizing plate, its manufacturing method, and a stacked film roll for a polarizing plate using the stack.

As a result of studies to solve the above problems, the present inventors found that by using "a polyvinyl alcohol resin film having a transmittance of light of a specified wavelength of 50% or more" and "a resin layer directly stacked on the film" The stacked body must solve the above problems, and then complete the present invention.

Therefore, according to the present invention, the following [1] to [18] can be provided.

[1] A stacked body for polarizing plates, comprising: A polyvinyl alcohol resin film with a light transmittance of more than 50% at a wavelength of 550 nm, and A resin layer directly stacked on at least one side of the polyvinyl alcohol resin film.

[2] The stacked body for polarizing plates according to [1], wherein the resin layer is a resin layer formed by coating the polyvinyl alcohol resin film with a resin.

[3] The polarizing plate stack according to [1] or [2], wherein the retardation Re1 in the in-plane direction of the polyvinyl alcohol resin film is 50 nm or less.

[4] The stacked body for polarizing plates according to any one of [1] to [3], wherein The thickness T of the aforementioned polyvinyl alcohol resin film is 45 μm or less, and The retardation Re2 in the in-plane direction of the extension of the resin layer is not less than 0 nm and not more than 20 nm, and the retardation Re2 is obtained by uniaxially extending the free end of the stack for polarizing plates at a temperature of 50°C to 120°C To 6.0 times, and when the aforementioned resin layer is made into the aforementioned extension, the phase difference of the aforementioned extension.

[5] The laminate for polarizing plates according to any one of [1] to [4], wherein the resin layer has a thickness of 50 μm or less.

[6] The stacked body for polarizing plates according to any one of [1] to [5], wherein the resin layer is made of a cycloolefin-based resin.

[7] The stacked body for polarizing plates according to [6], wherein The aforementioned cycloolefin-based resin includes a cycloolefin-based polymer, The aforementioned cycloolefin-based polymer is a hydrogenated block copolymer obtained by hydrogenating the block copolymer [D], and the block copolymer [D] is composed of: A polymer block [A] mainly composed of a repeating unit [I] derived from an aromatic vinyl compound, and Polymer block [B] mainly composed of repeating unit [I] derived from aromatic vinyl compound and repeating unit [II] derived from chain conjugated diene compound, or polymer block [B] derived from chain conjugated diene compound The repeating unit [II] of an alkene compound is formed as a polymer block [C] of the main component.

[8] The laminate for polarizing plates according to any one of [1] to [7], wherein the resin layer contains a plasticizer, a softener, or both.

[9] The polarizing plate stack according to [8], wherein the plasticizer, the softener, or both are one or more selected from ester-based plasticizers and aliphatic hydrocarbon polymers.

[10] The laminate for polarizing plates according to any one of [1] to [9], wherein the resin layer contains an organometallic compound.

[11] A polarizing plate in which the stacked body for polarizing plates according to any one of [1] to [10] is uniaxially stretched.

[12] A stacked film roll, which is wound into a roll shape and has: The stacked body for polarizing plates according to any one of [1] to [10], and A separator film stacked on the surface of the resin layer of the stacked body for polarizing plates that is opposite to the polyvinyl alcohol resin film.

[13] A method for manufacturing a stacked body for polarizing plates, which sequentially includes: The first process of coating resin on at least one side of a polyvinyl alcohol resin film with a light transmittance of 550 nm or more of 50% to form a resin layer; and A second step of drying the resin layer formed in the aforementioned first step.

[14] The method for producing a stacked body for polarizing plates according to [13], wherein the coating method is one or more methods selected from solution coating, emulsion coating, and melt extrusion coating.

[15] The method for producing a laminate for polarizing plates according to [13] or [14], including a third step of heat-treating the polyvinyl alcohol resin film before the first step.

[16] The method for producing a stacked body for polarizing plates according to any one of [13] to [15], comprising: prior to the first step, activating the surface of the polyvinyl alcohol resin film. The fourth process.

[17] A method for producing a polarizing plate, using the polarizing plate stack as described in any one of [1] to [10] or by using the polarizing plate as described in any one of [13] to [16] The method for manufacturing a polarizing plate obtained from the stacked body for a polarizing plate obtained by the method for manufacturing a stacked body for a polarizing plate, which includes: The fifth step of dyeing the aforementioned stacked body for polarizing plates with a dichroic dye, and A sixth step of uniaxially stretching the aforementioned stacked body for polarizing plates.

[18] The method for producing a polarizing plate as described in [17], comprising: after the aforementioned fifth step and/or the aforementioned sixth step, between the polyvinyl alcohol resin film and the resin of the stacked body for polarizing plates The seventh step of attaching the protective film to the surface on the opposite side of the layer.

According to the present invention, it is possible to provide a stacked body for a polarizing plate that "can be used even if the resin film (resin layer) is used as a protective film, and can be efficiently produced even if it is thin", and a method for producing the same, and a polarizing plate using the stacked body A method for manufacturing the same, and a stacked film roll.

Embodiments and examples are disclosed below to describe the present invention in detail. However, the present invention is not limited by the implementation forms and examples described below, and can also be implemented with arbitrary changes within the scope of the present invention without departing from the scope of the patent application and its equivalent scope.

In this application, the so-called "long" film refers to a film that has a length of 5 times or more, preferably 10 times or more, with respect to the width of the film, and specifically refers to a film that can be rolled. The length to be stored or transported in a roll shape. The upper limit of the ratio of the length to the film width is not particularly limited, but may be set at, for example, 100,000 times or less.

In this application, the retardation Re in the in-plane direction of the film and the retardation Rth in the thickness direction follow the formula Re=(nx-ny)×d and Rth={[(nx+ny)/2]-nz}×d And calculated. And the Nz coefficient of the thin film is a value represented by [(nx-nz)/(nx-ny)], which can also be expressed as [(Rth/Re)+0.5]. Here, nx is the refractive index in the direction of the slow axis in the plane of the film (the maximum refractive index in the plane), ny is the refractive index in the direction perpendicular to the slow axis in the plane of the film, and nz is the thickness direction of the film The refractive index, the thickness (nm) of the d-series film. The measurement wavelength is set to 550 nm, a representative wavelength in the visible light region, unless otherwise noted.

[Embodiment 1: Laminated body for polarizing plate and its manufacturing method, film roll of stacked body, polarizing plate and its manufacturing method]

The stacked body for polarizing plates (hereinafter also simply referred to as "stacked body"), the manufacturing method thereof, and the stacked body using the stacked body will be described below with reference to FIGS. 1 to 5 . A bulk film roll, a polarizing plate using the stack, and a manufacturing method thereof.

[1. Stack]

The stacked body of the present invention has: a polyvinyl alcohol resin film with a transmittance of 50% or more of light with a wavelength of 550 nm, and a resin layer directly stacked on at least one side of the polyvinyl alcohol resin film.

As stated clearly in the context of the article, in this application, the "resin layer" is a layer body different from the polyvinyl alcohol resin film.

In this application, the so-called "resin layer directly stacked" on the surface of the polyvinyl alcohol resin film is a resin layer in the following state: it is formed on the surface of the layer body of the material constituting the polyvinyl alcohol resin film, and the result is the same as that of the polyvinyl alcohol resin film. The surfaces of the polyvinyl alcohol resin films are directly in contact with each other.

FIG. 1 is an example of a schematic cross-sectional view of a stacked body 10 according to Embodiment 1 of the present invention. As shown in FIG. 1 , the stacked body 10 of this embodiment includes an unstretched polyvinyl alcohol resin film 11 and a resin layer 12 disposed on one side (upper side as shown) of the polyvinyl alcohol resin film 11 . The stacked body 10 of the present invention is a material used to manufacture polarizers (polarizers).

[Polyvinyl alcohol resin film]

In the present invention, the polyvinyl alcohol resin film has a transmittance of light with a wavelength of 550 nm (hereinafter also referred to as "transmittance of light with a wavelength of 550 nm" as "light transmittance") of 50% or more. film. In the present invention, an uncolored film is used as the polyvinyl alcohol resin film. The light transmittance of the polyvinyl alcohol resin film is preferably above 55%, preferably above 60%, preferably below 99%, preferably below 97%.

Polyvinyl alcohol resin film is an unstretched film made of polyvinyl alcohol resin (hereinafter, "polyvinyl alcohol" is sometimes abbreviated as "PVA"). In this application, the so-called "unstretched film" refers to one that has not been subjected to stretching treatment.

In the present invention, the PVA resin film (polyvinyl alcohol resin film) is not limited at all, but in terms of availability and the like, those produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate are good. The PVA contained in the PVA resin preferably has a degree of polymerization in the range of 500 to 8000, and a degree of saponification of 90 mol% or more, from the viewpoint of excellent extensibility and the polarizing performance of an obtainable polarizer. Here, the degree of polymerization is an average degree of polymerization measured in accordance with the description of JIS K6726-1994, and the degree of saponification is a value measured in accordance with the description of JIS K6726-1994. The preferred range of the degree of polymerization is 1000-6000, more preferably 1500-4000. The preferred range of saponification degree is above 95 mole %, more preferably above 99 mole %. PVA can also be a copolymer or graft polymer of vinyl acetate and other copolymerizable monomers.

In this invention, the manufacturing method of a PVA resin film is not specifically limited, It can manufacture by arbitrary methods, such as a well-known method. Examples of production methods include: cast film production using a PVA solution in which PVA is dissolved in a solvent as a film production stock solution, wet film production (draining into a poor solvent), dry and wet film production , Gel film-making method (first cooling the PVA aqueous solution to gel, then extracting and removing the solvent to obtain a PVA resin film) and a combination of these methods. As another example of the production method, there may be mentioned a melt-extrusion film-forming method in which a melted PVA containing a solvent is used as a film-forming stock solution. Among them, the cast film-making method and the melt-extrusion film-making method are preferable in terms of obtaining a PVA resin film with high transparency and little coloring, and the melt-extrusion method is preferable in terms of obtaining a high film-making speed. Membrane method is preferred.

In the present invention, the PVA resin film preferably contains 0.01 to 30% by weight of plasticizers such as glycerin and other polyols relative to the PVA in order to improve mechanical physical properties or smooth operation during secondary processing, and in order to improve handling It is preferable to contain 0.01 to 1% by weight of surfactants, such as anionic surfactants and nonionic surfactants, relative to PVA, in terms of properties or film appearance.

The PVA resin film may further contain optional components such as antioxidants, ultraviolet absorbers, lubricants, pH regulators, inorganic particles, colorants, preservatives, fungicides, other polymers other than the above components, and water, as needed. The PVA resin film may contain one or two or more of the aforementioned arbitrary components.

The thickness T of the PVA resin film is preferably not more than 45 μm, more preferably not more than 35 μm, more preferably not more than 25 μm, preferably not less than 5 μm, preferably not less than 10 μm, and more preferably not less than 15 μm better. When the thickness of the PVA resin film is not more than the upper limit of the above-mentioned range, the shrinkage force of the polarizing plate can be effectively reduced, and by being more than the lower limit of the above-mentioned range, a polarizing plate having a sufficiently high degree of polarization can be obtained.

The in-plane retardation Re1 of the PVA resin film is preferably less than 50 nm, more preferably less than 40 nm, more preferably less than 30 nm, preferably greater than 0 nm, more preferably greater than 3 nm. When the retardation Re1 in the in-plane direction of the PVA resin film is not more than the upper limit of the above-mentioned range, the stacked body can be stretched at a sufficient magnification, and a polarizing plate with a high degree of polarization can be obtained.

The shape and size of the PVA resin film are appropriately adjusted to correspond to the intended use. In terms of manufacturing efficiency, the PVA resin film is preferably a long film.

[Resin layer]

The resin layer is a layer body made of resin. The resin layer may be a resin layer formed by coating a resin with a PVA resin film. In the present invention, the resin forming the resin layer is preferably a flexible resin that can be stretched at a high extension ratio (such as 6.0 times) at a low temperature (such as 50 to 120 ° C), specifically, a cycloolefin-based resin better. The cycloolefin-based resin is a resin containing a cycloolefin-based polymer.

[Resin]

As the cycloolefin-based polymer contained in the cycloolefin-based resin, a hydrogenated block copolymer [D] obtained by hydrogenating the block copolymer [D] is preferably obtained from: A polymer block [A] composed mainly of a repeating unit [I] of an aromatic vinyl compound, and a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit derived from a chain conjugated diene compound [ II] A polymer block [B] as a main component or a polymer block [C] mainly comprising a repeating unit [II] derived from a chain-like conjugated diene compound. Examples of such hydrogenated block copolymers include: WO2000/32646, WO2001/081957, Japanese Patent Laid-Open No. 2002-105151, Japanese Patent Laid-Open No. 2006-195242, Japanese Patent Laid-Open No. 2011- Polymers described in Publication No. 13378, WO2015/002020, etc.

[Plasticizers and Softeners]

In the present invention, the resin forming the resin layer preferably contains a plasticizer and/or a softener (either or both of the plasticizer and the softener). By containing a plasticizer and/or a softener, it is possible to reduce the retardation generated in the resin layer when the laminate is stretched to obtain a polarizing plate.

As plasticizers and softeners, resins that can be uniformly dissolved or even dispersed to form a resin layer can be used. Specific examples of plasticizers and softeners include ester-based plasticizers composed of polyhydric alcohols and monocarboxylic acids (hereinafter referred to as "polyol ester-based plasticizers"), and ester-based plasticizers composed of polyhydric carboxylic acids and monocarboxylic acids. Ester-based plasticizers made of monohydric alcohols (hereinafter referred to as "polycarboxylic acid ester-based plasticizers") and other ester-based plasticizers, as well as phosphate-based plasticizers, sugar-ester-based plasticizers, and other polymeric material softener.

Examples of the polyhydric alcohol which is a raw material of the ester-based plasticizer preferably used in the present invention are not particularly limited, but ethylene glycol, glycerin, and trimethylolpropane are preferable.

Examples of polyol ester plasticizers include ethylene glycol ester plasticizers, glycerin ester plasticizers, and other polyol ester plasticizers.

As an example of a polybasic carboxylate plasticizer, a dicarboxylate plasticizer and other polybasic carboxylate plasticizers are mentioned.

Examples of phosphate-based plasticizers include: alkyl phosphates such as triacetyl phosphate and tributyl phosphate; cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate; triphenyl phosphate Phosphate esters, tricresyl phosphate and other aryl phosphate esters.

As the sugar ester-based plasticizer, specifically, glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, sucrose octaacetate, sucrose octabenzoate, etc. are preferred, among which Sucrose octaacetate is preferred.

Specific examples of polymer softeners include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, methyl methacrylate, and 2-hydroxymethacrylate. Acrylic polymers such as copolymers of ethyl esters, copolymers of methyl methacrylate and methyl acrylate with 2-hydroxyethyl methacrylate; polyvinyl isobutyl ether, poly-N-vinylhydropyrrolidone Ethylene-based polymers such as polystyrene, poly-4-hydroxystyrene and other styrene-based polymers; polybutylene succinate, polyethylene terephthalate, polyethylene naphthalate and other polyesters ; Polyethylene oxide, polypropylene oxide and other polyethers; polyamide, polyurethane, polyurea, etc.

Specific examples of aliphatic hydrocarbon polymers include low molecular weight products such as polyisobutene, polybutene, poly-4-methylpentene, poly-1-octene, ethylene-α-olefin copolymers, and their Hydrogenated products; low molecular weight products such as polyisoprene and polyisoprene-butadiene copolymer and their hydrogenated products. From the viewpoint of easy uniform dissolution and even dispersion in the cycloolefin resin, the number average molecular weight of the aliphatic hydrocarbon polymer is preferably 300-5,000.

These polymer softeners may be homopolymers consisting of one type of repeating unit, or copolymers having multiple repeating structures. In addition, the above-mentioned polymers may be used in combination of two or more.

In the present invention, the plasticizer and/or softener is preferably at least one selected from ester-based plasticizers and aliphatic hydrocarbon polymers in terms of excellent compatibility with the resin forming the resin layer. .

The proportion of the plasticizer and/or softener (hereinafter also referred to as "plasticizer, etc.") in the resin layer is preferably 0.2 parts by weight or more, and 0.5 parts by weight relative to 100 parts by weight of the resin forming the resin layer. It is preferably not less than 1.0 parts by weight, more preferably not less than 50 parts by weight, and more preferably not more than 40 parts by weight. By making the ratio of the plasticizer etc. into the said range, even after passing through the manufacturing process of the polarizing plate including stretching process, the resin layer can be made into the one which shows the retardation sufficiently low.

[Organometallic compounds]

In the present invention, the resin layer preferably contains an organometallic compound. By including the organometallic compound, it is possible to more effectively suppress the occurrence of peeling of the resin layer in the case of stretching the stacked body at a high stretching ratio (for example, wet stretching at a stretching ratio of 6.0).

The organometallic compound is a compound containing at least one of a chemical bond between a metal and carbon and a chemical bond between a metal and oxygen, and is a metal compound having an organic group. Examples of organometallic compounds include organosilicon compounds, organotitanium compounds, organoaluminum compounds, and organozirconium compounds. Among these, organosilicon compounds, organotitanium compounds, and organozirconium compounds are preferable, and organosilicon compounds are more preferable in terms of excellent reactivity with polyvinyl alcohol. Organometallic compounds can also be used alone or in combination of two or more.

Examples of organometallic compounds include organosilicon compounds represented by the following formula (1), but are not limited thereto. R ¹ _a Si(OR ² ) _{3 − a} (1) (In formula (1), R ¹ and R ² are independently selected from hydrogen atom, halogen atom, hydrocarbon group with 1 to 10 carbon atoms, epoxy group, amino group, mercapto group, isocyanate group and organic group with 1 to 10 carbon atoms, a represents an integer of 0 to 3.)

In the formula (1), if you want to give a good example as R ¹ , there are: epoxy group, amine group, mercapto group, isocyanate group, vinyl group, acryl group, aryl group, -CH ₂ OC _n H _2n+1 (n represents an integer of 1 to 4.), an alkyl group having 1 to 8 carbon atoms, and the like.

In addition, in the formula (1), as R ² , preferable examples include: a hydrogen atom, a vinyl group, an aryl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, and -CH ₂ OC _n H _2n+1 (n represents an integer from 1 to 4.) etc.

Examples of organosilicon compounds include epoxy-based organosilicon compounds such as 3-glycidoxypropyltrimethoxysilane and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-Aminopropyltrimethoxysilane, N-2-(Aminoethyl)-3-Aminopropyltrimethoxysilane and other amine organosilicon compounds, isocyanuric acid (trimethoxysilyl Isocyanate-based organosilicon compounds such as propyl) ester, mercapto-based organosilicon compounds such as 3-mercaptopropyltrimethoxysilane, and isocyanate-based organosilicon compounds such as 3-isocyanatopropyltriethoxysilane.

Examples of organic titanium compounds include titanium alkoxides such as tetraisopropyl titanate, titanium chelate compounds such as titanium acetylacetonate, and titanium acyl oxides such as titanium isostearate.

Examples of organic zirconium compounds include zirconium alkoxides such as n-propyl zirconate, zirconium chelates such as zirconium tetraacetylacetonate, and zirconyl acyl oxides such as zirconium stearate.

Examples of the organoaluminum compound include aluminum alkoxides such as secondary butylalumina and aluminum chelates such as aluminum triacetylacetonate.

The proportion of the organometallic compound in the resin layer is preferably at least 0.005 parts by weight, more preferably at least 0.01 parts by weight, and more preferably at least 0.03 parts by weight, relative to 100 parts by weight of the resin forming the resin layer. On the one hand, it is preferably not more than 1.0 parts by weight, more preferably not more than 0.5 parts by weight. By setting the ratio of the organometallic compound within the aforementioned range, it is possible to more effectively suppress the occurrence of peeling of the resin layer in the case of wet stretching the stacked body at a high magnification (for example, a stretching magnification of 6.0).

[arbitrary ingredients]

The resin layer has to contain optional components other than resins, plasticizers, organometallic compounds, and the like. Examples of optional components include stabilizers such as antioxidants, ultraviolet absorbers, and light stabilizers; resin modifiers such as slip agents; colorants such as dyes and pigments; and antistatic agents. These admixtures can be used alone or in combination of two or more, and the blending amount can be appropriately selected.

[Thickness of resin layer]

The thickness of the resin layer is preferably not less than 1 μm, more preferably not less than 3 μm, and preferably not more than 50 μm, more preferably not more than 20 μm. When the thickness of the resin layer is not less than the lower limit of the above-mentioned range, it is possible to effectively prevent the melting of the polarizer in the polarizing plate forming process, and by being not more than the upper limit of the above-mentioned range, it is possible to reduce the loss of the stretched stack. Retardation generated in the resin layer when obtaining a polarizing plate.

[Re2 of the resin layer]

Re2 of the resin layer is preferably not less than 0 nm and not more than 20 nm. Re2 is preferably above 0 nm, preferably below 10 nm, especially preferably below 5 nm. When Re2 is below an upper limit, the retardation which appears in a resin layer when stretching the laminated body 10 and making a polarizing plate can be made small.

Re2 refers to the surface of the extension of the resin layer when the free end of the stack 10 is uniaxially extended to 6.0 times at a temperature of 50°C to 120°C, and the resin layer in the stack is made into an extension The phase difference in the inner direction. In other words, Re2 is not the phase difference of the resin layer itself in the stack, but the phase difference generated in the extension of the resin layer after a specific stretching process is applied to the stack.

The extension temperature used to obtain such an extension can be any temperature within the range of 50°C to 120°C. Thus, a number of operating conditions for obtaining extension of the extension can be envisioned. In the case where the extension exhibits a phase difference of not less than 0 nm and not more than 20 nm due to any one of such a plurality of operating conditions, the stacked body satisfies the aforementioned requirements.

However, it is preferable that "the extension exhibits a phase difference of more than 0 nm and less than 20 nm due to all the above-mentioned multiple operating conditions obtained". In this case, in the manufacture of the polarizing plate through the stacked body for polarizing plates of the present invention, a high "degree of freedom in setting stretching conditions" can be obtained.

Generally speaking, in this temperature range, a larger phase difference will appear when the stretching temperature is lower. Therefore, as long as both the "retardation of the stretched product made by stretching at 50°C" and "the retardation of the stretched product made by stretching at 120°C" are within the range of 0 nm or more and 20 nm or less, that is It was judged that the extension exhibited a phase difference of not less than 0 nm and not more than 20 nm due to all of the aforementioned multiple operating conditions.

[2. Manufacturing method of stacked body]

The manufacturing method of the stacked body related to this embodiment includes in sequence: a first step of coating resin on at least one side of a PVA resin film with a light transmittance of 550 nm at a wavelength of 50% or more to form a resin layer; The second step of drying the resin layer formed in the first step.

And, the manufacturing method of stacked body also can comprise any process or two processes selected from the following: before the first process, the third process of heat-treating the PVA resin film, and carrying out activation treatment to the surface of the PVA resin film the fourth process.

[Manufacturing device of stacked body]

FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus 200 used in the method of manufacturing a stacked body according to this embodiment. The manufacturing device 200 includes an unwinding device 201 , a coating device 202 , a winding device 203 , a processing device 204 for performing treatments such as heat treatment and activation treatment, and a drying device 205 .

[Manufacturing method of stacked body]

As shown in Figure 2, the PVA resin film 11 unwound from the unwinding device 201 is transported to the processing device 204, and is selected from heat treatment (third process) and activation treatment (fourth process) in the processing device 204. After the treatment (processing step), the resin layer 12 is formed in the coating device 202 (first step) and dried in the drying device 205 (second step), to obtain the stacked body 10 . The manufactured stack 10 can be wound into a roll shape by the winding device 203 for further processing. Each step will be described below.

[First process]

The first process is the process of coating resin on at least one side of the PVA resin film 11 to form the resin layer 12 . The method (method of coating) of coating resin in PVA resin film 11 is not particularly limited, but is preferably selected from for example: more than one method of solution coating, emulsion coating or melt extrusion coating, with respect to Solution coating is preferable for a resin layer that can be coated at a high speed and can obtain a uniform film thickness.

In the case of forming the resin layer 12 by solution coating, the resin used for the formation of the resin layer 12 and components added if necessary are dissolved in a solvent to form a resin composition, and the resin composition is coated. Cover the PVA resin film 11. That is, the expression "coating resin" includes both "cases of coating only resin" and "cases of coating a resin composition including resin and other components".

[Second process]

The second step is a step of drying the resin layer formed in the first step.

In the second step, it is preferable to dry the resin layer for 0.5 minutes to 10 minutes in a dryer at a temperature of 50°C to 120°C. The drying temperature of the aforementioned resin layer is preferably above 60°C, more preferably above 70°C, preferably below 100°C, more preferably below 90°C. The drying time can be shortened by setting the drying temperature above the lower limit, and the crystallization of the PVA resin film can be suppressed by setting the drying temperature below the upper limit.

[Procedure]

The treatment step is a step of performing a treatment selected from heat treatment (third step) and activation treatment (fourth step).

[Third process]

The third step is a step of heat-treating the PVA resin film before the first step. In the present invention, the third step is an optional step, and may or may not be included. By heat-treating the PVA resin film in the third process, the wrinkles existing in the PVA resin film can be removed and the flatness can be improved. By smoothing the PVA resin film, the film thickness accuracy of the resin layer formed in the first process can be improved. The heating temperature of the PVA resin film is preferably above 50°C, more preferably above 60°C, preferably below 100°C, preferably below 90°C.

[Fourth process]

The fourth step is a step of activating the surface of the PVA resin film on which the resin layer is to be formed before the first step. In the present invention, the fourth step is an optional step, and may or may not be included. In the fourth process, by activating the surface of the PVA resin film, the plasticizer etc. seeping out to the surface of the PVA resin film is removed, and the surface of the PVA resin film is oxidized, thereby improving the adhesiveness of the resin layer and inhibiting the formation of the resin layer. The resin layer peeled off.

The method of activation treatment includes, for example, corona treatment, plasma treatment, saponification treatment, primer treatment, and anchor coating treatment.

The time to perform the fourth step is not limited as long as it is before the first step, and may be performed at any time before the third step, after the third step, or simultaneously with the third step. Since there is a possibility that the plasticizer contained in the PVA resin film may bleed out to the surface of the PVA resin film in the third step, it is particularly preferable to perform the fourth step after the third step.

[Use of the stack]

The stacked body 10 of the present invention is a material used to manufacture polarizers. The stacked body is made into a polarizing plate after being subjected to specified treatments such as stretching treatment and dyeing treatment. In the case where the stacked body 10 is used as the material of the polarizing plate, the stacked body wound up by the winding device 203 shown in FIG. 2 can be used directly, or the resin layer 12 of the stacked body wound by the winding device 203 Stacked on the separator, wound into a roll, and made into a stacked film roll for reuse. Hereinafter, the laminate film roll and the polarizing plate of this embodiment using the laminate 10 of this embodiment are demonstrated sequentially.

[3. Stacked film rolls]

FIG. 3 is a schematic cross-sectional view of a stacked film roll using the stacked body related to this embodiment.

As shown in FIG. 3 , the stacked body film roll 15 of this embodiment has a stacked body 10 and a surface (upper side in the figure) of the resin layer 12 stacked on the stacked body 10 opposite to the PVA resin film 11. The isolation film 13 is a film roll that is wound into a roll shape.

The separator 13 is not particularly limited as long as it is a film made of a material that can be peeled off from the resin layer 12. For example, a film made of a material selected from cycloolefin resins, acrylic resins, polyethylene A film made of one or more of vinyl resin, polypropylene resin and triacetyl cellulose resin.

[4. Manufacturing method of polarizing plate]

The polarizing plate 100 of the present invention can be obtained by uniaxially stretching the polarizing plate stack 10 of this embodiment. FIG. 4 is a schematic view showing an example of a manufacturing apparatus for manufacturing a polarizing plate using the stacked body for a polarizing plate according to this embodiment.

The manufacturing method of the polarizing plate of the present invention includes: a fifth step of dyeing the stacked body with a dichroic dye, and a sixth step of uniaxially stretching the stacked body.

Moreover, the manufacturing method of the polarizing plate of the present invention may also include: after passing through the fifth step and/or the sixth step, attaching the first layer of the protective film to the surface of the PVA resin film of the stacked body opposite to the resin layer. Seven procedures. The seventh step is an optional step, and in the embodiment, an example of manufacturing a polarizing plate by a manufacturing method that does not include the seventh step will be described.

［Apparatus for manufacturing polarizing plates］

As shown in FIG. 4 , the manufacturing apparatus 300 for manufacturing a polarizing plate includes unwinding apparatuses 301 & 307 , processing apparatuses 302 to 305 , drying apparatuses 306 & 309 , bonding apparatus 308 , and winding apparatus 310 .

[Manufacturing method of polarizing plate]

In this embodiment, the stacked body 10 unwound from the unwinding device 301 is transported to the processing devices 302-305, and the dyeing process (fifth process) of dyeing the PVA resin film 11 of the stacked body 10 is carried out, and the stacked body Stretching processing of uniaxial stretching (sixth process), and specified processing. The polarizing plate 100 can be obtained by performing the treatment (drying process) of “drying the stacked body after these treatments in the drying device 306 ”. Each step will be described in detail below.

[Fifth process]

The fifth step is a step of dyeing the PVA resin film 11 of the laminated body 10 . In this embodiment, although the PVA resin film of the stack is dyed, the dyeing of the PVA resin film can also be performed on the PVA resin film before forming the stack.

As a substance which dyes the PVA resin film in a 5th process, a dichroic substance is mentioned, and as a dichroic substance, an iodine, an organic dye, etc. are mentioned. The dyeing method using these dichroic substances is arbitrary. For example, dyeing can also be performed by immersing the layered body of the PVA resin film in a dyeing solution containing a dichroic substance. Furthermore, when using iodine as a dichroic substance, the dyeing solution may contain iodides, such as potassium iodide, from a viewpoint of improving dyeing efficiency. The dichroic substance is not particularly limited, but when the polarizing plate is used in a vehicle-mounted display device, an organic dye is preferable as the dichroic substance.

[Sixth process]

The sixth step is a step of uniaxially stretching the stacked body. The method for stretching the stack is not particularly limited, but wet stretching is preferable. The sixth step can also be performed at any time before the fifth step, after the fifth step, or simultaneously with the fifth step. In addition, the sixth step may be divided and performed multiple times before the fifth step, after the fifth step, or simultaneously with the fifth step. The stretching step may be performed once or twice or more.

The elongation ratio of the stacked body is preferably above 5.0, more preferably above 5.5, preferably below 7.0, preferably below 6.5. If the stretching magnification of the stacked body is set below the upper limit of the above-mentioned range, even after the production process of the polarizing plate including stretching treatment, the appearance of the retardation of the resin layer can be reduced, and the occurrence of cracking of the polarizing plate can be prevented, and A polarizing plate having sufficient polarizing performance can be obtained by setting the elongation ratio to be more than the lower limit of the aforementioned range. When stretching the stacked body two or more times, it is preferable that the total stretching ratio represented by the product of the respective stretching ratios falls within the aforementioned range.

The stretching temperature of the stack is not particularly limited, but it is preferably above 30°C, more preferably above 40°C, especially above 50°C, preferably below 140°C, preferably below 90°C , preferably below 70°C. Stretching can be smoothly performed by the stretching temperature being not less than the lower limit value of the aforementioned range, and effective orientation by stretching can be performed by being not more than the upper limit value of the aforementioned range. The range of the above-mentioned stretching temperature is suitable for both dry stretching and wet stretching, but it is especially preferable for wet stretching.

The stretching treatment of the stack may be any of the following: longitudinal stretching treatment for stretching along the long side direction of the film, transverse stretching treatment for stretching along the width direction of the film, stretching treatment along the direction neither parallel nor perpendicular to the film width Diagonal stretch processing that stretches diagonally. The stretching process of the stack is preferably uniaxially stretched at the free end, and more preferably uniaxially stretched at the free end in the longitudinal direction.

[Drying process]

The drying step is a step of drying the stack that has passed through the fifth step and the sixth step. In the drying process, it is preferable to dry the stacked body for 0.5 minutes to 10 minutes in a dryer at a temperature of 50°C to 100°C. The drying temperature of the aforementioned stacked body is preferably above 60°C, and preferably below 90°C. The drying time can be shortened by setting the drying temperature above the lower limit, and the cracking of the PVA resin film can be prevented by setting the drying temperature below the upper limit. The drying time of the stacked body is preferably more than 1 minute, and more preferably less than 5 minutes. By setting the drying time to be more than the lower limit, the above-mentioned stack can be sufficiently dried, and by setting the drying time to be below the upper limit, it is possible to prevent the cracking of the PVA resin film in the stack.

In conventional polarizers made only of films made of PVA resin, cracks sometimes occur after the drying process, but since the polarizer of this embodiment uses a resin that has a PVA resin film and is directly stacked on the PVA resin film It is manufactured by stacking the layers, so cracking of the polarizer can be suppressed even after the drying process.

[5. Polarizing plate]

A polarizing plate can be obtained by the above-mentioned manufacturing method of the polarizing plate of this embodiment. The polarizing plate of this embodiment is a polarizing plate in which the stacked body of this embodiment is stretched uniaxially. FIG. 5 is a schematic cross-sectional view of a polarizing plate manufactured using the stacked body related to this embodiment.

As shown in FIG. 5 , in the polarizing plate 100 , a resin layer 112 is stacked on one side (upper side as shown) of the PVA resin film 111 .

[Characteristics of each layer in the polarizing plate]

The thickness of the PVA resin film 111 in the polarizing plate 100 is preferably less than 20 μm, more preferably less than 10 μm, preferably more than 3 μm, more preferably more than 5 μm. When the thickness is not more than the upper limit, the thickness of the polarizing plate can be reduced, and when the thickness is not less than the lower limit, a polarizing plate having a sufficiently high degree of polarization can be obtained.

The retardation in the in-plane direction of the resin layer in the polarizing plate is preferably 20 nm or less, more preferably 15 nm or less, more preferably 10 nm or less, and preferably 0 nm or more. When the phase difference in the in-plane direction of the resin layer in the polarizing plate is within the above-mentioned range, black shift can be suppressed when the polarizing plate is mounted on a liquid crystal display device.

[Applications of Polarizing Plates]

The polarizing plate manufactured using the laminate for polarizing plates of this invention can be used as the material of a liquid crystal display device.

Generally, a liquid crystal display device is equipped with a light source, a light source-side polarizing plate, a liquid crystal cell, and a viewing-side polarizing plate in sequence. Can. The liquid crystal display device can be manufactured by arranging the polarizing plate of the present invention as both or one of the light source side polarizing plate and the viewing side polarizing plate on a liquid crystal panel.

And the polarizing plate manufactured using the laminated body for polarizing plates of this invention can be used as the material of an organic EL display device, an inorganic EL display device, etc.

Generally, an organic EL display device includes a substrate, a transparent electrode, a light-emitting layer, and a metal electrode layer sequentially from the light exit side, but the polarizer obtained by the manufacturing method of the present invention can be arranged on the light exit side of the substrate.

The EL display device has two substrates, a light-emitting layer located between them, and a polarizing plate arranged outside one of the two substrates. The display device can be manufactured by disposing the polarizing plate of the present invention on an organic EL panel or an inorganic EL panel.

[6. Functions and effects of this form of implementation]

In the present embodiment, since the polarizing plate is manufactured by stretching a stacked body having "a PVA resin film with a light transmittance of 50% or more" and "a resin layer directly stacked on the surface of the PVA resin film", Therefore, even when the stacked body is stretched at a high magnification at a low temperature, the occurrence of fusion of the PVA resin film can be suppressed, and the appearance of a phase difference in the stretched resin layer can be suppressed. As a result, according to this embodiment, it can be directly used as a protective film on one side of the PVA resin film without peeling off the resin layer, and wasteful materials can be reduced. A stack for a polarizing plate that can be efficiently produced even if it is thin, and a manufacturing method thereof, a polarizing plate using the stack and a manufacturing method thereof, and a film roll of the stack.

And, according to the present embodiment, since the resin layer 12 is directly stacked on the PVA resin film 11, there is no intermediary of other materials between the resin layer and the PVA resin film, so the fracture suppression effect is excellent, and the production environment can be prevented. Environmental pollution caused by other substances in the product, or the effect of preventing damage to the product (mixing of foreign matter).

[Example 2: Polarizing plate and its manufacturing method]

Referring to FIG. 4 and FIG. 6, the polarizing plate 120 and its manufacturing method related to Embodiment 2 will be described simultaneously. The polarizing plate 120 related to this embodiment is manufactured using the polarizing plate 100 related to the first embodiment. The same symbols are attached to the same structures and aspects as those of Embodiment 1, and repeated explanations are omitted.

[Polarizer]

FIG. 6 is a schematic cross-sectional view of a polarizing plate 120 related to Embodiment 2 of the present invention. In this polarizing plate 120, as shown in FIG. 6, a resin layer 112 is stacked on one side (upper side as shown) of a PVA resin film 111, and a resin layer 112 is stacked on the other side (lower side as shown) of the PVA resin film 111. ) is stacked with a protective film 115 . 114 in FIG. 5 is a bonding agent.

The manufacturing method of the polarizing plate 120 of this embodiment includes: after the fifth step and the sixth step, a seventh step of attaching a protective film to the surface of the PVA resin film of the stack body opposite to the resin layer. It is described in detail below.

The polarizing plate 120 of this embodiment is manufactured using the device shown in FIG. 4 . In the manufacturing method of the polarizing plate 120 of this embodiment, it is used: the dyeing treatment (the fifth step) of dyeing the PVA resin film 11 of the stacked body 10 and the stretching treatment (the sixth step) of uniaxially stretching the stacked body. ) Afterwards, the obtained polarizing plate 100 is dried in the drying device 306 .

The polarizing plate 120 can be placed on the opposite side of the PVA resin film of the stacked body from the resin layer by transporting the polarizing plate 100 obtained through the dyeing process (the fifth process) and the stretching process (the sixth process) to the bonding device 308 The surface (the surface on which the resin layer is not stacked) is coated with the adhesive 114 and bonded with the protective film 115 unwound from the unwinding device 307 (seventh step). The obtained polarizing plate 120 can be wound into a roll shape by the winding device 310 for further processing.

The adhesive 113 used in the seventh step to bond the protective film 115 to the PVA resin film 111 is not particularly limited, and examples thereof include acrylic adhesives, epoxy adhesives, and urethane adhesives. adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, modified polyolefin adhesives, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-acetic acid Vinyl ester-based adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer)-based adhesives, vinyl-based adhesives such as ethylene-styrene copolymers, ethylene-(meth)methacrylate copolymers, vinyl ―Acrylic adhesives such as (meth)ethyl acrylate copolymers, etc.

As the protective film 115 used in the seventh step, there can be mentioned one or more resins selected from the group consisting of cycloolefin resins, acrylic resins, polyethylene terephthalate resins, and triacetyl cellulose resins. film.

The polarizing plate of this embodiment is the same as the polarizing plate of Embodiment 1 by combining "a PVA resin film with a light transmittance of 50% or more" and "a resin layer directly stacked on the surface of the PVA resin film". The polarizing plate stack is stretched to manufacture the polarizing plate, so it has the same function and effect as that of Embodiment 1.

Moreover, according to the present embodiment, since the protective film 115 is provided on the surface of the PVA resin film 111 on the side where the resin layer 112 is not stacked, it also has the effect of preventing scratches etc. from being left on the surface of the PVA resin film 111 .

[Other Implementation Types]

Embodiment 1 discloses a laminate for polarizing plates in which a resin layer is laminated on one surface of a PVA resin film, and Embodiments 1 and 2 disclose polarizing plates produced using the above-mentioned stack, but this The invention is not limited thereto.

"Example"

The present invention will be described in further detail below with reference to examples and comparative examples, but the present invention is not limited by the following examples. "Parts" and "%" in the following about the quantitative ratio of ingredients represent parts by weight unless otherwise noted.

[Evaluation method]

[Weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn)]

The molecular weights of block copolymers and block copolymer hydrogenated products are measured at 38° C. as standard polystyrene conversion values of GPC using THF as an eluent. HLC8020GPC manufactured by TOSOH was used as a measuring device.

[Hydrogenation rate]

The hydrogenation rate of the hydrogenated block copolymer was calculated by ¹ H-NMR spectrum or GPC analysis. The area where the hydrogenation rate is less than 99% is calculated by measuring ¹ H-NMR spectrum, and the area where the hydrogenation rate exceeds 99% is calculated from the ratio of the peak areas of the UV detector and the RI detector by GPC analysis.

[Measurement method of phase difference]

The retardation Re1 and the retardation Re2 in the in-plane direction of the polyvinyl alcohol resin film, and the retardation in the in-plane direction of the resin layer in the polarizing plate were measured using a retardation meter (manufactured by OPTO SCIENCE, INC., trade name " Mueller matrix polarimeter (AxoScan)") measurement. When measuring, the measurement wavelength is set at 550 nm.

The measurement of the retardation Re2 is to measure the retardation in the in-plane direction of the resin layer produced when the free end of the stack is uniaxially extended to 6.0 times at the specified temperature (50°C and 120°C). In this application, as long as "the retardation in the in-plane direction of the resin layer generated when the free end of the stack is uniaxially stretched to 6.0 times at a temperature of 50°C" and "the stack is stretched at a temperature of 120°C The retardation in the in-plane direction of the resin layer produced when the free end of the body is uniaxially extended to 6.0 times" is within the range of 0 nm or more and 20 nm or less, then it is judged that "under the temperature condition of 50°C to 120°C When the free end of the stack is uniaxially extended to 6.0 times, the retardation Re2" of the in-plane direction of the resin layer is not less than 0 nm and not more than 20 nm.

[Measuring method of thickness]

The thickness of each film (polyvinyl alcohol resin film and resin layer) contained in the stack and the thickness of each film contained in the polarizing plate were measured using a thickness gauge (manufactured by Mitutoyo Corporation, trade name "ABS Digital Thickness Gauge (547 -401)") Measure 5 times, and set the average value as the thickness of each film.

[Evaluation of adhesion]

In the process from the production of the polarizing plate of each example to the second stretching treatment, the case where no peeling occurred between the polyvinyl alcohol resin film and the resin layer was designated as A, and the case where partial peeling was observed was designated as B, and The person who completely peeled off was rated as C.

[Evaluation of drying processability]

In the drying process at 70°C for 5 minutes in the production of the polarizing plate of each example, the case where no cracks occurred in the polarizer was rated as A, and the case where cracks occurred was rated as C.

[Evaluation of the bonded surface state of the stacked body]

Visually observe the number of air bubbles in a 10 cm square (100 cm ² ) of the stack.

[Black Offset]

Remove the liquid crystal display panel from the liquid crystal display device (manufactured by LG Electronics Japan, Inc., trade name "IPS panel display (23MP47)"), peel off the polarizing plate placed on the viewing side, and stick it so that the resin layer becomes the panel side Combining the polarizing plates produced in Examples and Comparative Examples. In addition, a single polarizer without a protective film was pasted next to the polarizers produced in Examples and Comparative Examples to reassemble the liquid crystal display device. The absorption axis of "the polarizing plates produced in Examples and Comparative Examples, and a single polarizer without a protective film" was bonded in the same direction as the absorption axis of the polarizing plate before peeling off.

When the direction of the absorption axis of the polarizing plate arranged on the viewing side is set as the azimuth angle of 0°, and the vertical direction of the panel is set as the polar angle of 0°, the panel is set to a black display state (that is, the entire display of the panel The state where the screen shows black), visually inspected from the azimuth angle of 45° and the polar angle of 45°, judged that the color change is the same as that of the polarizer without protective film as A, and judged that there was a slight color change as B, and judged The one with the largest change is judged as C.

[Example 1]

(1-1) Production of Polymer X

Referring to the production example described in Japanese Patent Publication No. 2002-105151, after polymerizing 25 parts of styrene monomer in the first stage, 30 parts of styrene monomer and 25 parts of isoprene monomer were polymerized in the second stage After polymerization, 20 parts of styrene monomers were polymerized in the third step to obtain a block copolymer [D1], and the block copolymer was hydrogenated to synthesize a hydrogenated block copolymer [E1]. The hydrogenated block copolymer [E1] has a Mw of 84,500, a Mw/Mn of 1.20, and a hydrogenation rate of the main chain and aromatic ring of almost 100%.

In 100 parts of hydrogenated block copolymer [E1], melt-knead 4{3-[3,5-bis(tertiary butyl)-4-hydroxyphenyl]propionic acid} neopentylthritol ester (Matsubara Sangyo Co., Ltd., product name "Songnox 1010") 0.1 part was blended as an antioxidant, and pelletized to obtain Polymer X for molding.

(1-2) Manufacture of stacked body

After dissolving the polymer X produced in (1-1) in cyclohexane, 40 parts by weight of polyisobutylene (manufactured by JX Nippon Oil & Energy Co., Ltd. HV-300", number average molecular weight 1,400) and 0.1 part by weight of an organosilicon compound (3-aminopropyltriethoxysilane, KBM903, manufactured by Shin-Etsu Chemical Co., Ltd.) to prepare a coating solution for film formation.

Apply the obtained coating solution for film formation to an unstretched polyvinyl alcohol resin film (average degree of polymerization about 2400, degree of saponification 99.9 mole%, width 650 mm, thickness 20 μm, hereinafter also referred to as Make one side of "PVA20") and dry. Thereby, a long stacked body composed of a PVA resin film and a resin layer (600 mm in width and 10 μm in thickness) containing polymer X was obtained.

The thickness of the resin layer in the obtained stack, the thickness of the polyvinyl alcohol resin film, and the phase difference Re1 and phase difference Re2 in the in-plane direction were measured (temperature conditions: 50°C, 120°C). The results are disclosed in Table 1.

(1-3) Manufacture of polarizing plate

The following operations were carried out while continuously conveying the guide roller in the stack produced in (1-2) in the longitudinal direction.

Swelling treatment of immersing in water, dyeing treatment of immersing in a dyeing solution containing iodine and potassium iodide, and first stretching treatment of extending the dyed stack are performed on the aforementioned stack. Subsequently, the stack after the first stretching process was subjected to a second stretching process of stretching in a bath containing boric acid and potassium iodide. The total stretching ratio represented by the product of the stretching ratio in the first stretching treatment and the stretching ratio in the second stretching treatment was set to be 6.0. The extension temperature was set at 57°C. The laminate after the second stretching treatment was dried in a dryer at 70° C. for 5 minutes (drying step) to obtain a polarizing plate.

The evaluation of adhesiveness was performed in the process up to the 2nd stretching process, the evaluation of drying processability was performed in a drying process, and the evaluation of black shift was performed about the obtained polarizing plate. The evaluation results are disclosed in Table 1.

In addition, the thickness and retardation of the resin layer in the obtained polarizing plate and the thickness of the polyvinyl alcohol resin film were measured, and the measurement results are disclosed in Table 1.

[Example 2]

Except in (1-2) of Example 1, 0.1 parts by weight of organotitanium compound (tetraisopropyl titanate, ORGATIX TA-8, manufactured by Matsumoto Fine Chemical Co., Ltd.) was added instead of 0.1 parts by weight In addition to forming a resin layer using a coating solution for film formation of an organosilicon compound, a stacked body and a polarizing plate were fabricated in accordance with Example 1, and evaluated in comparison with Example 1. The results are disclosed in Table 1.

[Example 3]

Except in (1-2) of Example 1, 0.1 parts by weight of organozirconium compound (n-propyl zirconate, ORGATIX ZA-45, manufactured by Matsumoto Fine Chemical Co., Ltd.) was added instead of 0.1 parts by weight of In addition to forming a resin layer using a coating solution for film formation of an organosilicon compound, a stacked body and a polarizing plate were manufactured in accordance with Example 1, and evaluated in comparison with Example 1. The results are disclosed in Table 1.

[Example 4]

Except in (1-2) of Example 1, when performing the operation of applying the coating liquid for film formation to the polyvinyl alcohol resin film using a die coater and drying it, the amount of coating etc. was adjusted so that the thickness became 5 μm. Except for forming a resin layer (the width is the same as that of Example 1) in the same way as in Example 1, a stacked body and a polarizing plate were fabricated and evaluated in comparison with Example 1. The results are disclosed in Table 1.

[Example 5]

Except that no polyisobutylene was used in (1-2) of Example 1, compared with Example 1, a stacked body and a polarizing plate were produced, and compared with Example 1, evaluation was performed. The results are disclosed in Table 2.

[Example 6]

Except that in (1-2) of Example 1, no organosilicon compound was used, and when the coating solution for film formation was applied to the polyvinyl alcohol resin film with a die coater and dried, the coating amount was adjusted, etc. Except for forming a resin layer (same width as in Example 1) so as to have a thickness of 5 μm, a stacked body and a polarizing plate were manufactured in accordance with Example 1, and evaluated in comparison with Example 1. The results are disclosed in Table 2.

[Comparative Example 1]

In (1-3) of Example 1, only an unstretched polyvinyl alcohol resin film (PVA20) was used instead of the stack produced in (1-2), and the same operation as (1-3) was performed As a result, melting occurred many times in the first stretching process and the second stretching process, and fractures occurred many times in the drying process, and the adhesiveness and black shift could not be evaluated.

[Reference example 1]

In (1-3) of Example 1, the following stacked body (R1-2) was used instead of the stacked body manufactured in (1-2) to produce a polarizing plate, and the same evaluation as Example 1 was performed. The results are disclosed in Table 2.

(R1-2) Manufacture of stacks

In (1-2) of Example 1, instead of applying the coating solution for film formation to the polyvinyl alcohol resin film, the coating solution for film formation was applied to the separator (manufactured by Mitsubishi Chemical Corporation, "MRV38") using a die coater. , and dried to obtain a long film (resin film) comprising polymer X having a width of 650 mm, a length of 500 m, and a thickness of 10 μm.

Mix 100 parts by weight of water, 3 parts by weight of a polyvinyl alcohol-based adhesive ("Z-200" manufactured by Nippon Synthetic Chemicals Co., Ltd.), and 0.3 parts by weight of a crosslinking agent ("SPM-01" manufactured by Nippon Synthetic Chemicals Co., Ltd.) to obtain a joint. agent. Apply this bonding agent on one side of the above resin film, and stick the unstretched polyvinyl alcohol resin film (the average degree of polymerization is about 2400, the degree of saponification is 99.9 mol%, the width is 650 mm, and the thickness is 20 μm, hereinafter also referred to as " PVA20"). In this state, the adhesive was heated and dried at 70° C. for 5 minutes to obtain a stacked body.

The evaluation results of Examples, Comparative Examples and Reference Examples are shown in Table 1 and Table 2.

In the table, the so-called "Re2 (50°C)" means the phase difference in the in-plane direction of the resin layer generated when the free end of the stack is uniaxially stretched to 6.0 times at a temperature of 50°C, and the so-called " Re2 (120°C)" means the retardation in the in-plane direction of the resin layer produced when the free end of the stack is uniaxially stretched to 6.0 times under the temperature condition of 120°C.

In the table, "Re1" means the retardation in the in-plane direction of the polyvinyl alcohol resin film in the stack.

In the table, "coating" means forming a resin layer by coating a film-forming coating solution (resin composition) on a polyvinyl alcohol resin film, and "bonding" means bonding a resin film to a polyvinyl alcohol resin film with an intermediary adhesive. Vinyl alcohol resin film.

"Table 1"

"Table 2"

As can be seen from the results in Table 1 and Table 2, according to the present invention, the phase difference that appears in the resin layer after the process of stretching the stack can be reduced, and a polarizing plate with excellent adhesion, drying processability, and optical physical properties can be obtained. . From this, it can be seen that it is possible to provide a stacked body for a polarizing plate that "can be used even if the resin layer is used as a protective film, and can be efficiently produced even if it is thin", and a manufacturing method thereof, a polarizing plate using the aforementioned stacked body, and a manufacturing method thereof , and stacked film rolls.

10‧‧‧Stack (stack for polarizer) 11‧‧‧Polyvinyl alcohol resin film (PVA resin film) 12‧‧‧resin layer 13‧‧‧Isolation film 15‧‧‧Stack film roll 100, 120‧‧‧polarizer 111‧‧‧Polyvinyl alcohol resin film (PVA resin film) 112‧‧‧resin layer 114‧‧‧Adhesive layer 115‧‧‧Protective film 200‧‧‧Manufacturing device 201, 202‧‧‧rolling out device 203‧‧‧Rewinding device 205‧‧‧Drying device 300‧‧‧Manufacturing device 301, 307‧‧‧rolling out device 302～305‧‧‧processing device 306, 309‧‧‧drying device 308‧‧‧Laminating device 310‧‧‧Rewinding device

<FIG. 1> FIG. 1 is a schematic cross-sectional view of a stacked body for polarizing plates related to Embodiment 1 of the present invention.

<FIG. 2> FIG. 2 is a schematic diagram showing an example of a manufacturing apparatus for a stacked body for polarizing plates related to Embodiment 1.

<FIG. 3> FIG. 3 is a schematic cross-sectional view of a stacked film roll manufactured by using the stacked body for polarizing plates according to Embodiment 1 of the present invention.

<FIG. 4> FIG. 4 is a schematic diagram showing an example of a manufacturing apparatus for manufacturing a polarizing plate using the polarizing plate stack according to Embodiment 1.

<FIG. 5> FIG. 5 is a schematic cross-sectional view of a polarizing plate manufactured using the stacked body for polarizing plates related to Embodiment 1 of the present invention.

<FIG. 6> FIG. 6 is a schematic cross-sectional view of a polarizing plate related to Embodiment 2 of the present invention.

10‧‧‧Stack (stack for polarizer)

11‧‧‧Polyvinyl alcohol resin film (PVA resin film)

12‧‧‧resin layer

Claims (16)

A stacked body for polarizing plates, comprising: a polyvinyl alcohol resin film with a transmittance of 50% or more of light with a wavelength of 550 nm, and a resin layer directly stacked on at least one side of the polyvinyl alcohol resin film, wherein the resin layer Contains a cycloolefin-based resin and an organometallic compound, and the ratio of the organometallic compound in the resin layer is 0.005 parts by weight to 0.5 parts by weight relative to 100 parts by weight of the resin forming the resin layer. The stacked body for polarizing plates according to claim 1, wherein the resin layer is a resin layer formed by coating the polyvinyl alcohol resin film with a resin. The stacked body for polarizing plates according to claim 1 or 2, wherein the retardation Re1 in the in-plane direction of the polyvinyl alcohol resin film is 50 nm or less. The stacked body for polarizing plates according to claim 1 or 2, wherein the thickness T of the polyvinyl alcohol resin film is 45 μm or less, and the retardation Re2 in the in-plane direction of the extension of the resin layer is 0 nm or more and 20 nm or less , the retardation Re2 is uniaxially extended to 6.0 times the free end of the polarizing plate stack under the temperature condition of 50°C~120°C, and when the resin layer is made into the extension, the extension has Phase difference. The stacked body for polarizing plates according to claim 1 or 2, wherein the resin layer has a thickness of 50 μm or less. The stacked body for polarizing plates according to claim 1 or 2, wherein The cyclic olefin resin comprises a cyclic olefin polymer, the cyclic olefin polymer is a hydrogenated block copolymer obtained by hydrogenating the block copolymer [D], and the block copolymer [D] is composed of: A polymer block [A] mainly composed of a repeating unit [I] derived from an aromatic vinyl compound, and a repeating unit derived from a repeating unit [I] derived from an aromatic vinyl compound and a chain conjugated diene compound The polymer block [B] mainly composed of the unit [II], or the polymer block [C] mainly composed of the repeating unit [II] derived from a chain conjugated diene compound. The stacked body for polarizing plates according to claim 1 or 2, wherein the resin layer contains a plasticizer, a softener, or both. The stacked body for polarizing plates according to Claim 7, wherein the plasticizer, the softener, or both are one or more selected from ester plasticizers and aliphatic hydrocarbon polymers. A polarizing plate, which is a stacked body for polarizing plates according to any one of Claims 1 to 8, which is uniaxially stretched. A stacked film roll, which is wound into a roll shape, and has: the stacked body for polarizing plates according to any one of claims 1 to 8, and the resin layer stacked on the stacked body for polarizing plates and A separator on the opposite side of the polyvinyl alcohol resin film. A method for manufacturing a stacked body for polarizing plates, which sequentially includes: The first process of coating resin and a resin composition containing an organic metal compound on at least one side of a polyvinyl alcohol resin film with a light transmittance of 550 nm or more to form a resin layer; The second step of drying the resin layer formed in , wherein the resin layer contains a cycloolefin resin and an organometallic compound, and the proportion of the organometallic compound in the resin layer is 100 parts by weight of the resin forming the resin layer , is not less than 0.005 parts by weight and not more than 0.5 parts by weight. The method for manufacturing a stacked body for polarizing plates according to claim 11, wherein the coating method is one or more methods selected from solution coating, emulsion coating or melt extrusion coating. The method for manufacturing a stacked body for polarizing plates according to claim 11 or 12, which includes a third step of heat-treating the polyvinyl alcohol resin film before the first step. The method for manufacturing a stacked body for polarizing plates according to claim 11 or 12, comprising: prior to the first step, a fourth step of activating the surface of the polyvinyl alcohol resin film. A method of manufacturing a polarizing plate, which uses the stacked body for polarizing plates according to any one of Claims 1 to 8 or the stacked body for polarizing plates according to any one of Claims 11 to 14 A method of manufacturing a polarizing plate from the stacked body for polarizing plates obtained by the manufacturing method, which includes: a fifth step of dyeing the stacked body for polarizing plates with a dichroic dye, and A sixth step of uniaxially stretching the stacked body for polarizing plates. The method of manufacturing a polarizing plate according to claim 15, which includes: after the fifth step and/or the sixth step, on the opposite side of the resin layer of the polyvinyl alcohol resin film of the polarizing plate stack The seventh step of attaching the protective film to the side surface.

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