JP7294142B2 - LAMINATE FOR POLARIZING PLATE, POLARIZING PLATE, DISPLAY DEVICE, AND METHOD FOR MANUFACTURING POLARIZING PLATE - Google Patents

Description

TECHNICAL FIELD The present invention relates to a polarizing plate laminate, a polarizing plate, a display device, and a method for manufacturing a polarizing plate.

2. Description of the Related Art Display devices such as liquid crystal display devices and organic electroluminescence (EL) display devices have conventionally been required to have a large display area, a light weight, and a small thickness. For this reason, thin panels that form display devices have been conventionally desired.

A polarizing plate including a polarizer and a protective film for protecting the polarizer is generally used in a display device. In order to construct a thin display device, a thinner polarizing plate is required. In particular, since the polarizer may shrink in the usage environment of the display device, warping due to such shrinkage may become a problem in a display device that is thin and has a large area. Therefore, by adopting a thin polarizer having a thickness of 10 μm or less, in addition to reduction in the thickness of the display device due to the reduction in the thickness of the polarizer itself, reduction in the occurrence of warping as described above can be expected.

However, when it is attempted to manufacture such a thin polyvinyl alcohol polarizer by a conventional manufacturing method, the polarizer is frequently melted. Several methods have been proposed as methods for preventing such melt-down of the polarizer and manufacturing a polarizing plate containing a thin polarizer.
For example, in Patent Document 1, a polyvinyl alcohol-based resin layer is formed into a laminate by applying an aqueous solution containing a polyvinyl alcohol-based resin to an amorphous ester-based thermoplastic resin substrate, and the laminate is stretched. A method of obtaining an optical film by orienting a dichroic substance after treatment to form a colored laminate and stretching the colored laminate has been proposed.

Japanese Patent No. 4691205 (corresponding publication: US Patent No. 8314987)

When a thin polarizing plate is produced by the method described in Patent Document 1, a retardation may occur in the base film after the stretching treatment due to the stretching of the laminate at a high stretching ratio. In such a case, it is difficult to use the base film as it is as a polarizing plate protective film, and the base film is peeled off and discarded, resulting in wasted material. Furthermore, an operation of separately preparing a protective film for protecting the polarizing plate and attaching it to the polarizing plate may occur.

Therefore, the present invention provides a polarizing plate laminate that can be efficiently manufactured even if the substrate film is thin and can be used as a protective film, a polarizing plate and a display device comprising the laminate, Another object of the present invention is to provide a method for manufacturing the polarizing plate.

As a result of studies to solve the above problems, the present inventors have found a polyvinyl alcohol resin film having an in-plane retardation and thickness within a predetermined range, and a flexible resin that can be stretched at a low temperature and at a high magnification. The inventors have found that the above problems can be solved by using a base film consisting of and completed the present invention.
Therefore, according to the present invention, the following [1] to [15] are provided.
[1] A polarizing plate laminate comprising an unstretched polyvinyl alcohol resin film and a base film,
The polyvinyl alcohol resin film has an in-plane retardation Re1 of 50 nm or less and a thickness T of 45 μm or less,
The base film is a film made of resin,
The resin has a melt flow rate of 1 g/10 minutes or more, and the melt flow rate is a value measured at 190 ° C. and a load of 2.16 kg,
The resin has a tensile modulus E of 50 MPa or more and 1200 MPa or less,
The retardation Re2 in the in-plane direction of the stretched product of the base film is 0 nm or more and 20 nm or less, and the retardation Re2 is 6.0 times the polarizing plate laminate under a temperature condition of 50 ° C. to 120 ° C. A laminate for a polarizing plate, which is a retardation possessed by the stretched product obtained by uniaxially stretching the free end of the substrate film into the stretched product.
[2] The resin is a cycloolefin resin,
The cycloolefin-based resin contains a cycloolefin-based polymer,
a polymer block [A] in which the cycloolefin-based polymer comprises a repeating unit [I] derived from an aromatic vinyl compound as a main component;
A polymer block [B] containing, as main components, a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a chain conjugated diene compound, or a repeating unit [II] derived from a chain conjugated diene compound, a polymer block [C] as a main component;
A block copolymer [D] consisting of
The laminate for a polarizing plate according to [1], which is a hydrogenated block copolymer hydride.
[3] A polarizing plate laminate comprising an unstretched polyvinyl alcohol resin film and a base film,
The polyvinyl alcohol resin film has an in-plane retardation Re1 of 50 nm or less and a thickness T of 45 μm or less,
The base film is a film made of resin,
The resin is a cycloolefin resin,
The cycloolefin-based resin contains a cycloolefin-based polymer,
a polymer block [A] in which the cycloolefin-based polymer comprises a repeating unit [I] derived from an aromatic vinyl compound as a main component;
A polymer block [B] containing, as main components, a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a chain conjugated diene compound, or a repeating unit [II] derived from a chain conjugated diene compound, a polymer block [C] as a main component;
A block copolymer [D] consisting of
A hydrogenated block copolymer hydride,
The retardation Re2 in the in-plane direction of the stretched product of the base film is 0 nm or more and 20 nm or less, and the retardation Re2 is 6.0 times the polarizing plate laminate under a temperature condition of 50 ° C. to 120 ° C. A laminate for a polarizing plate, which is a retardation possessed by the stretched product obtained by uniaxially stretching the free end of the substrate film into the stretched product.
[4] The polarizing plate laminate of [2] or [3], wherein the cycloolefin resin contains a plasticizer, a softener, or both.
[5] The polarizing plate laminate of [4], wherein the plasticizer, the softener, or both of them are one or more selected from an ester plasticizer and an aliphatic hydrocarbon polymer.
[6] The polarizing plate laminate of any one of [1] to [5], wherein the resin contains an organometallic compound.
[7] The laminate for a polarizing plate according to any one of [1] to [6], wherein the base film is laminated on the polyvinyl alcohol resin film via an adhesive layer.
[8] A polarizing plate obtained by uniaxially stretching the polarizing plate laminate according to any one of [1] to [7].
[9] The polarizing plate of [8], wherein the surface of the polyvinyl alcohol resin film of the polarizing plate on which the base film is not laminated has a protective film or an adhesive.
[10] The polarizing plate of [9], wherein the protective film is made of one or more resins selected from cycloolefin resins, acrylic resins, polyethylene terephthalate resins, and triacetylcellulose resins.
[11] Two substrates, a liquid crystal layer positioned between them,
and a polarizing plate according to any one of [8] to [10] arranged outside at least one of the two substrates.
[12] two substrates, a light-emitting layer positioned between them,
and a polarizing plate according to any one of [8] to [10] arranged outside one of the two substrates.
[13] The display device according to [11], wherein a base film of the polarizing plate is provided between the polyvinyl alcohol resin film of the polarizing plate and the liquid crystal layer.
[14] The display device according to [12], wherein a base film of the polarizing plate is provided between the polyvinyl alcohol resin film of the polarizing plate and the light-emitting layer.
[15] A method for producing a polarizing plate, comprising a step of uniaxially stretching the polarizing plate laminate of any one of [1] to [7].

According to the present invention, a laminate for a polarizing plate that can be efficiently manufactured even if the substrate film is thin and can be used as a protective film, a polarizing plate and a display device using the laminate, Also, a method for producing a polarizing plate using the laminate can be provided.

FIG. 1 is a cross-sectional view schematically showing a polarizing plate laminate according to Embodiment 1 of the present invention. FIG. 2 is a diagram schematically showing an example of a manufacturing apparatus for a polarizing plate laminate according to Embodiment 1. FIG. FIG. 3 is a cross-sectional view schematically showing a polarizing plate manufactured using the polarizing plate laminate according to Embodiment 1 of the present invention. FIG. 4 is a diagram schematically showing an example of a manufacturing apparatus for manufacturing a polarizing plate using the polarizing plate laminate according to Embodiment 1. FIG. FIG. 5 is a cross-sectional view schematically showing a polarizing plate of Modification 1 manufactured using the polarizing plate laminate according to Embodiment 1 of the present invention. FIG. 6 is a cross-sectional view schematically showing a polarizing plate of Modification 2 manufactured using the polarizing plate laminate according to Embodiment 1 of the present invention. FIG. 7 is a cross-sectional view schematically showing a polarizing plate laminate according to Embodiment 2 of the present invention. FIG. 8 is a cross-sectional view schematically showing a polarizing plate manufactured using the polarizing plate laminate according to Embodiment 2 of the present invention. FIG. 9 is a cross-sectional view schematically showing a polarizing plate of Modification 3 manufactured using the polarizing plate laminate according to Embodiment 2 of the present invention. FIG. 10 is a cross-sectional view schematically showing a polarizing plate of Modification 4 manufactured using the polarizing plate laminate according to Embodiment 2 of the present invention. FIG. 11 is a cross-sectional view schematically showing a display device according to Embodiment 3 of the present invention. FIG. 12 is a cross-sectional view schematically showing a display device according to Embodiment 4 of the present invention. FIG. 13 is a cross-sectional view schematically showing a display device according to Embodiment 5 of the present invention. FIG. 14 is a cross-sectional view schematically showing a display device according to Embodiment 6 of the present invention. FIG. 15 is a cross-sectional view schematically showing a display device according to Embodiment 7 of the present invention. FIG. 16 is a cross-sectional view schematically showing a display device according to Embodiment 8 of the present invention.

Hereinafter, the present invention will be described in detail by showing embodiments and examples. However, the present invention is not limited to the embodiments and examples described below, and may be arbitrarily modified without departing from the scope of the claims of the present invention and equivalents thereof.

In the present application, the term "long-shaped" film refers to a film having a length of 5 times or more, preferably 10 times or more, of the width of the film. It is long enough to be rolled up and stored or transported. Although the upper limit of the ratio of the length to the width of the film is not particularly limited, it can be, for example, 100,000 times or less.

In the present application, the retardation Re in the in-plane direction and the retardation Rth in the thickness direction of the film are calculated according to the formulas Re=(nx−ny)×d and Rth=[{(nx+ny)/2}−nz]×d. do. The Nz coefficient of the film is a value represented by [(nx-nz)/(nx-ny)] and can also be represented by [(Rth/Re)+0.5]. Here, nx is the refractive index in the in-plane slow axis direction of the film (in-plane maximum refractive index), and ny is the refractive index in the in-plane direction perpendicular to the in-plane slow axis of the film. , nz is the refractive index in the thickness direction of the film, and d is the thickness (nm) of the film. Unless otherwise specified, the measurement wavelength is 550 nm, which is a typical wavelength in the visible light region.

[Embodiment 1: Laminate for polarizing plate and polarizing plate]
Hereinafter, a polarizing plate laminate of Embodiment 1, which is one embodiment of the present invention, a polarizing plate produced using the laminate, and a method for producing the same will be described with reference to FIGS. 1 to 4. FIG.
[1. Laminate for polarizing plate]
A laminate for a polarizing plate of the present invention (hereinafter also simply referred to as "laminate") includes an unstretched polyvinyl alcohol resin film and a base film. FIG. 1 is an example of a cross-sectional view schematically showing a laminate 10 of Embodiment 1 according to the present invention. As shown in FIG. 1 , the laminate 10 of this embodiment includes an unstretched polyvinyl alcohol resin film 11 and a base film 12 provided on the polyvinyl alcohol resin film 11 . In FIG. 1, 13 is an adhesive for bonding the polyvinyl alcohol resin film 11 and the base film 12 together. The laminate 10 of the present invention is a material for manufacturing a polarizer (polarizing plate).

[Polyvinyl alcohol resin film]
In the present invention, the polyvinyl alcohol resin film is a film having an in-plane retardation Re1 of 50 nm or less and a thickness T of 45 μm or less. A polyvinyl alcohol resin film is an unstretched film made of polyvinyl alcohol resin (hereinafter, "polyvinyl alcohol" may be abbreviated as "PVA"). In the present application, "unstretched film" refers to a film that has not been stretched.

In the present invention, the PVA resin film (polyvinyl alcohol resin film) is not necessarily limited, but from the viewpoint of availability, it is preferable to use a film produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate. is preferred. 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 stretchability and polarizing performance of the resulting polarizer. preferable. Here, the degree of polymerization is the average degree of polymerization measured according to JIS K6726-1994, and the degree of saponification is the value measured according to JIS K6726-1994. A more preferred range of the degree of polymerization is 1,000 to 6,000, more preferably 1,500 to 4,000. A more preferable range of saponification degree is 95 mol % or more, more preferably 99 mol % or more. PVA may be a copolymer or a graft polymer of vinyl acetate and other copolymerizable monomers.

In the present invention, the method for producing the PVA resin film is not particularly limited, and it can be produced by any method such as a known method. Examples of manufacturing methods include a casting film-forming method, a wet film-forming method (discharging into a poor solvent), a dry-wet film-forming method, and a gel film-forming method using a PVA solution obtained by dissolving PVA in a solvent as a film-forming stock solution. method (method of obtaining a PVA resin film by cooling and gelling a PVA aqueous solution once and then extracting and removing the solvent to obtain a PVA resin film), and a method using a combination thereof. A further example of the production method is a melt extrusion film-forming method in which a solvent-containing PVA is melted as a film-forming stock solution. Among these, the casting film-forming method and the melt-extrusion film-forming method are preferable because a PVA resin film with high transparency and little coloration can be obtained, and the melt-extrusion film-forming method is more preferable.

In the present invention, the PVA resin film contains a plasticizer such as a polyhydric alcohol such as glycerin in an amount of 0.01 to 30% by weight relative to the PVA in order to improve the mechanical properties and process passability during secondary processing. 0.01 to 1% by weight of PVA of surfactants such as anionic surfactants and nonionic surfactants to improve handling and film appearance. is preferred.

The PVA resin film may optionally contain antioxidants, ultraviolet absorbers, lubricants, pH adjusters, inorganic fine particles, colorants, preservatives, antifungal agents, other polymeric compounds other than the above components, moisture, etc. may further contain optional components. The PVA resin film can contain one or more of the above optional components.

The thickness T of the PVA resin film is 45 µm or less, preferably 35 µm or less, more preferably 25 µm or less, still more preferably 20 µm or less, preferably 5 µm or more, more preferably 10 µm or more, and still more preferably 15 µm or more. . When the thickness of the PVA resin film is equal to or less than the upper limit of the range, the shrinkage force of the polarizing plate can be effectively reduced, and when the thickness is equal to or greater than the lower limit of the range, the polarizing plate has sufficiently high polarizing performance. can be obtained.

The in-plane retardation Re1 of the PVA resin film is 50 nm or less, preferably 40 nm or less, more preferably 30 nm or less, still more preferably 20 nm or less, preferably 0 nm or more, more preferably 3 nm or more. When the in-plane retardation Re1 of the PVA resin film is equal to or less than the upper limit of the above range, the laminate can be stretched at a sufficient magnification, and a polarizing plate with high polarizing performance can be obtained.

The shape and dimensions of the PVA resin film can be appropriately adjusted according to the desired application. From the viewpoint of production efficiency, the PVA resin film is preferably a long film.

[Base film]
The base film is a layer separate from the PVA resin film and is a film made of resin. In the present invention, the resin forming the base film is a resin having flexibility capable of being stretched at a low temperature (eg, 50 to 120° C.) at a high draw ratio (eg, 6.0 times). In the present invention, the resin forming the base film is a resin (resin A) having a melt flow rate of 1 g/10 minutes or more and a tensile elastic modulus E of 50 MPa or more and 1200 MPa or less, or a predetermined cyclo It is a cycloolefin resin (resin B) containing an olefin polymer.

[Resin A]
In the present invention, the melt flow rate of the resin A forming the base film is 1 g/10 min or more, preferably 3 g/10 min or more, more preferably 5 g/10 min or more, and preferably 300 g/10 min or less. , more preferably 100 g/10 minutes or less. The melt flow rate referred to here is a value measured at 190° C. and a load of 2.16 kg. Hereinafter, "melt flow rate measured at 190°C and a load of 2.16 kg" is also simply referred to as "MFR". By setting the MFR of the resin A to the lower limit or more, the retardation of the polarizing plate can be kept small, and by setting the MFR to the upper limit or less, the heat resistance can be enhanced.

The MFR of resin A can be measured according to JIS-K-7210 using a melt indexer under conditions of a temperature of 190° C. and a load of 2.16 kg.

In the present invention, the tensile modulus E of the resin A forming the base film is 50 MPa or more, preferably 100 MPa or more, more preferably 200 MPa or more, and 1200 MPa or less, preferably 1000 MPa or less, more preferably 800 MPa or less. . By setting the tensile modulus E of the resin A to the lower limit or more, the retardation of the base film is reduced when the laminate is stretched to form a polarizing plate, and by setting it to the upper limit or less, the laminate is stretched. It is possible to prevent breakage of the base film when the coating is applied.

The resin A forming the base film is not particularly limited as long as it has an MFR of 1 g/10 min or more and a tensile elastic modulus E of 50 MPa or more and 1200 MPa or less. A cycloolefin-based resin containing a cycloolefin-based polymer is preferable from the viewpoint of excellent properties and water vapor barrier properties.

As the cycloolefin-based polymer, a polymer block [A] mainly composed of repeating units [I] derived from an aromatic vinyl compound, and a repeating unit [I] derived from an aromatic vinyl compound and a chain conjugated diene compound A block copolymer consisting of a polymer block [B] whose main component is the repeating unit [II] derived from A hydrogenated block copolymer obtained by hydrogenating the coalescence [D] is preferred. Such block copolymer hydrides include WO2000/32646, WO2001/081957, JP-A-2002-105151, JP-A-2006-195242, JP-A-2011-13378, and WO2015/002020. , and the like.

[Resin B]
In the present invention, the resin B forming the base film is a cycloolefin resin containing a cycloolefin polymer. The cycloolefin-based polymer contained in the resin B comprises a polymer block [A] mainly composed of repeating units [I] derived from an aromatic vinyl compound, repeating units [I] derived from an aromatic vinyl compound and a chain A polymer block [B] mainly composed of repeating units [II] derived from a conjugated diene compound, or a polymer block [C] mainly composed of repeating units [II] derived from a chain conjugated diene compound. Block copolymer hydride obtained by hydrogenating block copolymer [D]. As such a hydrogenated block copolymer, the same hydrogenated block copolymer as the aforementioned hydrogenated block copolymer which is suitably used as the resin A can be used.

The resin B forming the base film may be a resin having an MFR of 1 g/10 minutes or more and a tensile elastic modulus E of 50 MPa or more and 1200 MPa or less.

[Plasticizer and softening agent]
In the present invention, the resins (resin A and resin B) forming the base film preferably contain a plasticizer and/or a softening agent (one or both of the plasticizer and the softening agent). By containing a plasticizer and/or a softening agent, it is possible to reduce the retardation generated in the base film when the polarizing plate is obtained by stretching the laminate.

As the plasticizer and softener, those that can be uniformly dissolved or dispersed in the resin forming the base film can be used. Specific examples of plasticizers and softeners include an ester plasticizer composed of a polyhydric alcohol and a monovalent carboxylic acid (hereinafter referred to as a "polyhydric alcohol ester plasticizer"), and a polyhydric carboxylic acid and a monovalent (hereinafter referred to as "polyvalent carboxylic acid ester plasticizer"), phosphate ester plasticizers, carbohydrate ester plasticizers, and other polymer softeners is mentioned.

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

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

Examples of polycarboxylic acid ester plasticizers include dicarboxylic acid ester plasticizers and other polycarboxylic acid ester plasticizers.

Specific examples of phosphate ester plasticizers include alkyl phosphates such as triacetyl phosphate and tributyl phosphate; cycloalkyl phosphates such as tricyclopentyl phosphate and cyclohexyl phosphate; triphenyl phosphate and tricresyl phosphate. phosphate aryl esters such as

Specific preferred carbohydrate ester plasticizers include glucose pentaacetate, glucose pentapropionate, glucose pentabutyrate, saccharose octaacetate, saccharose octabenzoate, etc. Of these, saccharose octaacetate is more preferred. preferable.

Specific examples of polymer softeners include aliphatic hydrocarbon polymers, alicyclic hydrocarbon polymers, polyethyl acrylate, polymethyl methacrylate, and mixtures of methyl methacrylate and 2-hydroxyethyl methacrylate. Acrylic polymers such as copolymers, copolymers of methyl methacrylate, methyl acrylate and 2-hydroxyethyl methacrylate; vinyl polymers such as polyvinyl isobutyl ether and poly N-vinylpyrrolidone; polystyrene, poly4 -Styrenic polymers such as hydroxystyrene; polyesters such as polybutylene succinate, polyethylene terephthalate and polyethylene naphthalate; polyethers such as polyethylene oxide and polypropylene oxide; polyamides, polyurethanes and polyureas.

Specific examples of aliphatic hydrocarbon polymers include low molecular weight substances such as polyisobutylene, polybutene, poly-4-methylpentene, poly-1-octene, ethylene/α-olefin copolymers, and hydrides thereof; polyisoprene , polyisoprene-butadiene copolymers, and hydrides thereof. The aliphatic hydrocarbon-based polymer preferably has a number average molecular weight of 300 to 5,000 from the viewpoint of uniform dissolution or dispersibility in the cycloolefin resin.

These polymeric softening agents may be homopolymers consisting of one type of repeating unit or copolymers having a plurality of repeating structures. Also, two or more of the above polymers may be used in combination.

In the present invention, the plasticizer and/or softening agent is one or more selected from ester plasticizers and aliphatic hydrocarbon polymers because of their particularly excellent compatibility with the resin forming the base film. is preferred.

The ratio of the plasticizer and/or softener (hereinafter also referred to as "plasticizer, etc.") in the base film is preferably 0.2 parts by weight or more, more preferably 100 parts by weight of the resin forming the base film. is 0.5 parts by weight or more, more preferably 1.0 parts by weight or more, and preferably 50 parts by weight or less, more preferably 40 parts by weight or less. By setting the ratio of the plasticizer and the like within the above range, the substrate film can be made to exhibit sufficiently low retardation even after undergoing a polarizing plate manufacturing process including a stretching treatment.

[Organometallic compound]
In the present invention, the substrate film preferably contains an organometallic compound. By containing the organometallic compound, it is possible to more effectively suppress the occurrence of peeling of the base film when the laminate is stretched at a high draw ratio (for example, wet drawing at a draw ratio of 6.0).

An 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. Organic metal compounds include organic silicon compounds, organic titanium compounds, organic aluminum compounds, organic zirconium compounds, and the like. Among these, organic silicon compounds, organic titanium compounds and organic zirconium compounds are preferred, and organic silicon compounds are more preferred because of their excellent reactivity with polyvinyl alcohol. The organometallic compounds may be used singly or in combination of two or more.

Examples of organometallic compounds include, but are not limited to, organosilicon compounds represented by the following formula (1).
R ¹ _a Si(OR ² ) _3-a (1)
(In Formula (1), R ¹ and R ² each independently represent a hydrogen atom, a halogen atom, a hydrocarbon group having 1 to 10 carbon atoms, an epoxy group, an amino group, a thiol group, an isocyanate group and a carbon represents a group selected from the group consisting of organic groups having 1 to 10 atoms, and a represents an integer of 0 to 3.)

In formula (1), preferred examples of R ¹ include an epoxy group, an amino group, a thiol group, an isocyanate group, a vinyl group, an aryl group, an acrylic group, an alkyl group having 1 to 8 carbon atoms, and —CH ₂ OC. _n H _2n+1 (n represents an integer of 1 to 4) and the like.
In formula (1), preferred examples of R ² include a hydrogen atom, a vinyl group, an aryl group, an acryl group, an alkyl group having 1 to 8 carbon atoms, —CH ₂ OC _n H _2n+1 (n is 1 represents an integer of up to 4.) and the like.

Examples of organosilicon compounds include epoxy-based organosilicon compounds such as 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, 3-aminopropyltrimethoxysilane, N- Amino-based organosilicon compounds such as 2-(aminoethyl)-3-aminopropyltrimethoxysilane, isocyanurate-based organosilicon compounds such as tris-(trimethoxysilylpropyl)isocyanurate, 3-mercaptopropyltrimethoxysilane and the like Isocyanate-based organosilicon compounds such as mercapto-based organosilicon compounds and 3-isocyanatopropyltriethoxysilane are included.

Examples of organic titanium compounds include titanium alkoxides such as tetraisopropyl titanate, titanium chelates such as titanium acetylacetonate, and titanium acylates such as titanium isostearate.

Examples of organic zirconium compounds include zirconium alkoxides such as normal propyl zirconate, zirconium chelates such as zirconium tetraacetylacetonate, and zirconium acylates such as zirconium stearate.

Examples of organoaluminum compounds include aluminum alkoxides such as aluminum secondary butoxide and aluminum chelates such as aluminum trisacetylacetonate.

The proportion of the organometallic compound in the substrate film is preferably 0.005 parts by weight or more, more preferably 0.01 parts by weight or more, and still more preferably 0.005 parts by weight or more, with respect to 100 parts by weight of the resin forming the substrate film. 03 parts by weight or more, preferably 1.0 parts by weight or less, and more preferably 0.5 parts by weight or less. By setting the proportion of the organometallic compound within the above range, it is possible to more effectively suppress the occurrence of peeling of the base film when the laminate is wet-stretched at a high draw ratio (for example, a draw ratio of 6.0). can.

[Optional component]
The base film may contain optional components in addition to resins, plasticizers, organometallic compounds, and the like. Examples of optional ingredients include stabilizers such as antioxidants, ultraviolet absorbers and light stabilizers; resin modifiers such as lubricants; colorants such as dyes and pigments; These compounding agents can be used singly or in combination of two or more, and the amount to be compounded is appropriately selected within a range that does not impair the object of the present invention.

[Method for producing base film]
The base film is a composition (hereinafter also referred to as "resin composition") containing components (resin and optionally added components) for forming the base film, formed into a film by any molding method. It can be manufactured by molding.

Examples of methods for molding the resin composition into a film include cast molding, extrusion molding, and inflation molding.

The thickness of the substrate film is preferably 1 µm or more, more preferably 3 µm or more, preferably 50 µm or less, and more preferably 20 µm or less. When the thickness of the base film is at least the lower limit of the range, it is possible to effectively prevent melting of the polarizer in the process of forming a polarizing plate. It is possible to reduce the retardation generated in the base film when the polarizing plate is obtained by the above method.

[Laminate production method]
FIG. 2 is a schematic diagram schematically showing an example of a laminate manufacturing apparatus 200 according to this embodiment. The manufacturing apparatus 200 includes feeding devices 201 and 202 , a bonding device 205 and a winding device 203 .

As shown in FIG. 2, the PVA resin film 11 fed out from the feeding device 201 is conveyed to the bonding device 205, the adhesive is applied in the bonding device 205, and the base film 12 fed out from the feeding device 202 is applied. The laminated body 10 is obtained by bonding together. The manufactured laminate 10 can be wound by a winding device 203 into a roll shape and subjected to further processes.

The adhesive 13 for bonding the PVA resin film 11 and the base film 12 together is not particularly limited, and examples include acrylic adhesives, urethane adhesives, polyester adhesives, polyvinyl alcohol adhesives, polyolefin adhesives, and adhesives. Adhesives, modified polyolefin adhesives, polyvinyl alkyl ether adhesives, rubber adhesives, vinyl chloride-vinyl acetate adhesives, SEBS (styrene-ethylene-butylene-styrene copolymer) adhesives, ethylene-styrene Ethylene-based adhesives such as copolymers, acrylate-based adhesives such as ethylene-methyl (meth)acrylate copolymers and ethylene-ethyl (meth)acrylate copolymers, and the like can be used. It is possible to more effectively suppress the occurrence of separation between the PVA resin film 11 and the base film 12 when the laminate is wet-stretched at a high draw ratio (for example, a draw ratio of 6.0). is preferred.

The surface of the base film 12 to be attached to the PVA resin film or the surface of the PVA resin film to be attached to the base film 12 is subjected to an easy adhesion treatment such as corona treatment, saponification treatment, primer treatment, or anchor coating treatment. processing may be applied.

[Laminate]
In the present invention, Re2 is 0 nm or more and 20 nm or less. Re2 is preferably 0 nm or more, preferably 10 nm or less, more preferably 5 nm or less. When Re2 is equal to or less than the upper limit value, it is possible to reduce the retardation that appears in the base film when the laminate 10 is stretched to form a polarizing plate.
Re2 is obtained by uniaxially stretching the laminate 10 to 6.0 times at the free end under a temperature condition of 50 ° C. to 120 ° C., and making the substrate film in the laminate a stretched product. , is the phase difference in the in-plane direction. That is, Re2 is not the phase difference of the base film itself in the laminate, but the phase difference that occurs in the stretched base film after the laminate is subjected to a specific stretching treatment.
The stretching temperature for obtaining such a stretched product may be any temperature within the range of 50°C to 120°C. Therefore, multiple operating conditions are conceivable for stretching to obtain the stretch. When the stretched product exhibits a retardation of 0 nm or more and 20 nm or less under any one of these operation conditions, the laminate satisfies the above requirements.
However, it is preferable that the stretched product expresses a retardation of 0 nm or more and 20 nm or less under all of the plurality of possible operation conditions. In this case, a high degree of freedom in setting stretching conditions can be obtained in the production of a polarizing plate using the laminate for a polarizing plate of the present invention.
Generally, in the temperature range, when the stretching temperature is lower, a larger retardation is developed. Therefore, if both the retardation of the stretched product obtained by stretching at 50° C. and the retardation of the stretched product obtained by stretching at 120° C. are within the range of 0 nm or more and 20 nm or less, the stretched product is 0 nm under all of the plurality of operating conditions. It can be judged that a retardation of 20 nm or less is exhibited.

The laminate 10 of the present invention is a material for manufacturing a polarizing plate. The laminate is made into a polarizing plate after being subjected to predetermined treatments such as stretching treatment and dyeing treatment. The polarizing plate of the present invention manufactured using the laminate 10 of the present embodiment will be described below.

[2. Polarizer]
The polarizing plate 100 of the present invention is obtained by uniaxially stretching the laminate 10 of the present embodiment. FIG. 3 is a cross-sectional view schematically showing a polarizing plate 100 manufactured using the laminate 10 according to this embodiment.

As shown in FIG. 3, in the polarizing plate 100, a base film 112 is laminated on one surface (upper surface in the drawing) of a PVA resin film 111. As shown in FIG. In FIG. 3, 113 is an adhesive layer.

[Method for producing polarizing plate]
A method for manufacturing a polarizing plate using the laminate according to Embodiment 1 of the present invention will be described. FIG. 4 is a diagram schematically showing an example of a manufacturing apparatus 300 for manufacturing the polarizing plate 100 using the laminate 10 according to this embodiment.

As shown in FIG. 4, the manufacturing apparatus 300 includes feeding devices 301 and 307 , processing devices 302 to 305 , drying devices 306 and 309 , bonding device 308 and winding device 310 .

The method for producing the polarizing plate of the present invention includes a step of uniaxially stretching the laminate of the present invention (stretching treatment step). The method for producing a polarizing plate of the present invention may include a dyeing treatment step of dyeing the laminate and/or a drying step of drying the laminate. In the present embodiment, the laminate 10 fed out from the feeding device 301 is conveyed to the processing devices 302 to 305, and a dyeing process (dyeing process) for dyeing the PVA resin film of the laminate is carried out, and the laminate is uniaxially stretched. A stretching treatment (stretching treatment step) and a predetermined treatment are performed. The polarizing plate 100 is obtained by performing a process (drying process) of drying the laminate after performing these processes in a drying device 306 . Each step will be described in detail below.

[Stretching process]
In the present embodiment, the stretching treatment step is a step of uniaxially stretching the laminate. Although the method for stretching the laminate is not particularly limited, wet stretching is preferred. The stretching step may be performed once or twice or more.

The draw ratio of the laminate is preferably 5.0 or more, more preferably 5.5 or more, and preferably 7.0 or less, more preferably 6.5 or less. When the stretch ratio of the laminate is set to the upper limit value or less of the above range, the expression of the retardation of the base film is reduced and the occurrence of breakage of the polarizing plate is prevented even after the manufacturing process of the polarizing plate including the stretching treatment. A polarizing plate having sufficient polarizing performance can be obtained by setting the draw ratio to the lower limit of the above range or more. When the laminate is stretched twice or more, it is preferable that the total stretch ratio represented by the product of the stretch ratios for each stretch falls within the above range.

The stretching temperature of the laminate is not particularly limited, but is preferably 30° C. or higher, more preferably 40° C. or higher, particularly preferably 50° C. or higher, preferably 140° C. or lower, more preferably 90° C. or lower. Preferably, it is 70°C or less. When the stretching temperature is equal to or higher than the lower limit of the above range, stretching can be smoothly performed, and when it is equal to or lower than the upper limit of the above range, effective orientation can be achieved by stretching. The stretching temperature range is preferable for both dry stretching and wet stretching, and is particularly preferable for wet stretching.

The laminate may be stretched in the longitudinal direction of the film, laterally stretched in the width direction of the film, or diagonally stretched in an oblique direction that is neither parallel nor perpendicular to the width direction of the film. may be performed. The stretching treatment of the laminate is preferably free uniaxial stretching, more preferably free uniaxial stretching in the longitudinal direction.

[Dyeing treatment process]
The dyeing process is a process of dyeing the PVA resin film of the laminate. In the present embodiment, the method for producing a polarizing plate includes a dyeing treatment (step) for dyeing the PVA resin film of the laminate, but in the present invention, the dyeing treatment is optional and may not be included. . The dyeing treatment step may be performed before the stretching treatment. Moreover, the dyeing of the PVA resin film may be performed on the PVA resin film before forming the laminate.

The substance for dyeing the PVA resin film in the dyeing process includes a dichroic substance, and examples of the dichroic substance include iodine and organic dyes. Dyeing methods using these dichroic substances are optional. For example, dyeing may be performed by immersing a layer of PVA resin film in a dyeing solution containing a dichroic substance. Further, when iodine is used as the dichroic substance, the dyeing solution may contain an iodide such as potassium iodide from the viewpoint of increasing dyeing efficiency. Although the dichroic substance is not particularly limited, organic dyes are preferable as the dichroic substance when the polarizing plate is used in a vehicle-mounted display device.

[Drying process]
The drying step is a step of drying the laminate that has undergone treatment steps such as a dyeing treatment step and a stretching treatment step. In the drying step, the laminate after the treatment step is preferably dried in a dryer at a temperature of 50° C. to 100° C. for 0.5 to 10 minutes. The drying temperature of the laminate is more preferably 60° C. or higher, and more preferably 90° C. or lower. By setting the drying temperature to the lower limit or higher, the drying time can be shortened, and by setting the drying temperature to the upper limit or lower, cracking of the PVA resin film can be prevented. The drying time of the laminate is more preferably 1 minute or longer, and more preferably 5 minutes or shorter. By setting the drying time to the lower limit or more, the laminate can be sufficiently dried, and by setting the drying time to the upper limit or less, cracking of the PVA resin film in the laminate can be prevented.

Conventional thin-film polarizers made only of PVA resin may crack after the drying process. Since the polarizer is manufactured, cracking of the polarizer can be suppressed even after the drying process.

[Characteristics of each layer in the polarizing plate]
The thickness of the PVA resin film in the polarizing plate is preferably 20 µm or less, more preferably 10 µm or less, preferably 3 µm or more, and more preferably 5 µm or more. When the thickness is equal to or less than the upper limit, the thickness of the polarizing plate can be reduced, and when the thickness is equal to or more than the lower limit, a polarizing plate having sufficiently high polarizing performance can be obtained.

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

[3. Actions and effects of the present embodiment]
In the present embodiment, a laminate including a PVA resin film having a small in-plane retardation Re1 and a small thickness and a base film made of a flexible resin capable of being stretched at a low temperature at a high magnification is provided. Since the polarizing plate is produced by stretching, even when the laminate is stretched at a low temperature and at a high magnification, it is possible to suppress the occurrence of fusing of the PVA resin film, and the retardation of the base film after stretching can be reduced. Expression can be suppressed. As a result, according to the present embodiment, the base film can be used as a protective film on one side of the PVA resin film as it is without being peeled off, and waste material can be reduced. can also be used as a protective film, and it is possible to provide a method for producing a polarizing plate that can be efficiently produced even if the thickness is small.

[Modification 1]
Hereinafter, a polarizing plate 120 of Modification 1 manufactured using the laminate 10 according to Embodiment 1 of the present invention will be described with reference to FIGS. 4 and 5. FIG.

FIG. 5 is a cross-sectional view schematically showing a polarizing plate 120 of Modification 1 manufactured using the laminate 10 according to Embodiment 1 of the present invention. In this polarizing plate 120, as shown in FIG. 5, a base film 112 is laminated on one side (upper side in the drawing) of the PVA resin film 111, and the other side (lower side in the drawing) of the PVA resin film 111 is laminated. A protective film 115 is laminated on the side surface). In FIG. 5, 113 and 114 are adhesive layers. As the adhesive for bonding the protective film 115 to the PVA resin film, the same adhesive as that for bonding the base film to the PVA resin film can be used.

The manufacturing method of the polarizing plate 120 according to this example includes a step of bonding the protective film 115 to the PVA resin film 111 of the polarizing plate 100 obtained in Embodiment 1 directly or via an adhesive.

Specifically, as shown in FIG. 4, the polarizing plate 100 of Embodiment 1 is transported to a lamination apparatus 308, and an adhesive 114 is applied to the surface of the PVA resin film 111 on the side where the base film 112 is not laminated. The polarizing plate 120 having the protective film 115 is obtained by applying the protective film 115 and attaching it to the protective film 115 delivered from the delivery device 307 . The manufactured polarizing plate 120 can be wound by a winding device 310 into a roll shape and subjected to further processes.

In this example, as the protective film 115, a film made of one or more resins selected from cycloolefin resin, acrylic resin, polyethylene terephthalate resin, and triacetyl cellulose resin can be used.

Similarly to the polarizing plate of Embodiment 1, the polarizing plate of this example is also made of a PVA resin film having a small in-plane direction retardation Re1 and a small thickness, and a flexible resin that can be stretched at a low temperature at a high magnification. Since the polarizing plate is manufactured by stretching the laminate containing the base film, the same effects as those of the first embodiment are obtained.

Further, according to this example, since the surface of the PVA resin film 111 on which the base film 112 is not laminated is provided with the protective film 115, the surface of the PVA resin film 111 is prevented from being damaged. Play.

[Modification 2]
Hereinafter, the polarizing plate 130 of Modification 2 manufactured using the laminate 10 according to Embodiment 1 of the present invention will be described with reference to FIG.
FIG. 6 is a cross-sectional view schematically showing a polarizing plate 130 of Modification 2 manufactured using the laminate 10 according to Embodiment 1 of the present invention.

FIG. 6 is a cross-sectional view schematically showing the polarizing plate 130 of this example. In this polarizing plate 130, as shown in FIG. 6, a base film 112 is laminated on one side (upper side in the drawing) of the PVA resin film 111, and the other side (lower side in the drawing) of the PVA resin film 111 is laminated. side) is laminated with an adhesive layer 116 .

The manufacturing method of the polarizing plate 130 according to this example includes the step of providing the adhesive layer 116 on the PVA resin film 111 of the polarizing plate 100 obtained in the first embodiment.

As the adhesive that forms the adhesive layer 116, various commercially available adhesives, for example, an adhesive containing an acrylic polymer as a main component polymer can be used.
The polarizing plate 130 of this example is, for example, a film having a commercially available adhesive layer (for example, Fujimori Kogyo (manufactured by "Mastak Series") to form an adhesive layer.

Like the polarizing plate of Embodiment 1, the polarizing plate 130 of this example also has a small in-plane retardation Re1, a thin PVA resin film, and a flexible resin that can be stretched at a low temperature at a high magnification. Since the polarizing plate is manufactured by stretching the laminate containing the base film made of and, the same effects as those of the first embodiment are obtained.

Further, according to this example, since the surface of the PVA resin film 111 on which the base film 112 is not laminated is provided with the adhesive layer 116, the surface of the PVA resin film 111 is prevented from being damaged. also play.

[Embodiment 2: Laminate for polarizing plate and polarizing plate]
7 and 8 for a laminate 15 (laminate for polarizing plate) according to Embodiment 2 of the present invention, a polarizing plate 150 produced using the laminate 15, and a method for producing the same. I will explain as I go along. The same reference numerals are assigned to the same configurations and modes as those of the first embodiment, and duplicate descriptions are omitted.

FIG. 7 is a cross-sectional view schematically showing a laminate 15 according to Embodiment 2 of the present invention, and FIG. 8 schematically shows a polarizing plate 150 manufactured using the laminate 15 according to this embodiment. It is a sectional view.

[Laminate]
The laminate 15 of this embodiment differs from the laminate of Embodiment 1 in that the base film 12 is directly laminated on the PVA resin film 11 .

Examples of methods for directly laminating the base film 12 on the PVA resin film 11 include heat fusion, ultrasonic fusion, and laser fusion. In the present application, the base film "directly laminated" on the surface of the PVA resin film means that the PVA resin film and the base film are separately prepared and laminated so as to be in direct contact without interposing other layers. including cases where

The laminate 15 of the present embodiment can also be used as a material for manufacturing a polarizing plate, like the laminate 10 of the first embodiment.

[Polarizer]
The polarizing plate 150 of the present invention manufactured using the laminate 15 of the present embodiment will be described below. The polarizing plate 150 is obtained by uniaxially stretching the laminate 10 of this embodiment.

As shown in FIG. 8, in the polarizing plate 150, the base film 112 is directly laminated on one side (upper side in the figure) of the PVA resin film 111. As shown in FIG. The polarizing plate 150 of this embodiment can also be manufactured by the same method as the polarizing plate 100 of the first embodiment.

[Effect of this embodiment]
Also in this embodiment, as in the polarizing plate of Embodiment 1, it is composed of a PVA resin film having a small in-plane direction retardation Re1 and a small thickness, and a flexible resin that can be stretched at a low temperature at a high magnification. Since the polarizing plate 150 is manufactured by stretching the laminate including the base film, the same effects as in the first embodiment are obtained.

Further, according to the present embodiment, since a laminate in which the base film 12 is directly laminated on the PVA resin film 11 is used, it is excellent in the effect of suppressing breakage, prevents environmental pollution due to other substances in the production environment, and improves the product. It also has the effect of preventing contamination (mixing of foreign matter).

[Modification 3]
Hereinafter, a polarizing plate 160 of Modified Example 3 manufactured using the laminate 15 according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 9 is a cross-sectional view schematically showing a polarizing plate 160 of Modification 3 manufactured using the laminate according to Embodiment 2 of the present invention.

In the polarizing plate 160, as shown in FIG. 9, the base film 112 is laminated on one side (upper side in the drawing) of the PVA resin film 111, and the other side (lower side in the drawing) of the PVA resin film 111 is laminated. ) is laminated with a protective film 115 via an adhesive layer 114 . As the adhesive 114 for bonding the protective film 115 to the PVA resin film 111, the same adhesive as the adhesive for bonding the base film to the PVA resin film described in the first embodiment can be used.

The manufacturing method of the polarizing plate 160 according to this example includes a step of bonding the protective film 115 to the PVA resin film 111 of the polarizing plate 150 obtained in the second embodiment with an adhesive. The protective film 115 and the method of laminating the protective film are the same as in the first modification.

Like the polarizing plate of Embodiment 1, the polarizing plate 160 of this example also has a small in-plane retardation Re1, a thin PVA resin film, and a flexible resin that can be stretched at a low temperature at a high magnification. Since the polarizing plate is manufactured by stretching the laminate containing the base film made of and, the same effects as those of the first embodiment are obtained.

In addition, according to this example, since the laminate 15 in which the base film 12 is directly laminated on the PVA resin film 11 is used, it is excellent in the effect of suppressing breakage, prevents environmental pollution due to other substances in the production environment, and improves the product. It also has the effect of preventing contamination (mixing of foreign matter).

Furthermore, according to this example, since the surface of the PVA resin film 111 on which the base film 112 is not laminated is provided with the protective film 115, the surface of the PVA resin film 111 is prevented from being damaged. Play.

[Modification 4]
Hereinafter, a polarizing plate 170 of Modification 4 manufactured using the laminate 15 according to Embodiment 2 of the present invention will be described with reference to FIG. FIG. 10 is a cross-sectional view schematically showing a polarizing plate 170 of Modification 4 manufactured using the laminate according to Embodiment 2 of the present invention.

In the polarizing plate 170, as shown in FIG. 10, a base film 112 is laminated on one surface (upper side in the drawing) of the PVA resin film 111, and the other side (lower side in the drawing) of the PVA resin film 111 is laminated. ) is laminated with an adhesive layer 116 .

The manufacturing method of the polarizing plate 170 according to this example includes the step of providing the adhesive layer 116 on the PVA resin film 111 of the polarizing plate 150 obtained in the second embodiment.
The method of forming the adhesive layer 116 and the adhesive used for forming the adhesive layer 116 are the same as those of the second modification.

Similarly to the polarizing plate of Embodiment 1, the polarizing plate 170 of this example also has a small in-plane retardation Re1, a thin PVA resin film, and a flexible resin that can be stretched at a low temperature at a high magnification. Since the polarizing plate is manufactured by stretching the laminate containing the base film made of and, the same effects as those of the first embodiment are obtained.

In addition, according to this example, since the laminate 15 in which the base film 12 is directly laminated on the PVA resin film 11 is used, it is excellent in the effect of suppressing breakage, prevents environmental pollution due to other substances in the production environment, and improves the product. It also has the effect of preventing contamination (mixing of foreign matter).

Furthermore, according to this example, since the adhesive layer 116 is provided on the side of the PVA resin film 111 on which the base film 112 is not laminated, the effect of preventing the surface of the PVA resin film 111 from being scratched or the like. also play.

[Embodiment 3: Display device]
A polarizing plate manufactured using the polarizing plate laminate of the present invention can be used as a material for a liquid crystal display device.
Usually, a liquid crystal display device comprises a light source, a light source side polarizing plate, a liquid crystal cell and a viewing side polarizing plate in this order. may be used.

Liquid crystal cell driving methods include, for example, in-plane switching (IPS) mode, vertical alignment (VA) mode, multi-domain vertical alignment (MVA) mode, continuous spin wheel alignment (CPA) mode, and hybrid alignment nematic (HAN) mode. mode, twisted nematic (TN) mode, super twisted nematic (STN) mode, optically compensated bend (OCB) mode, and the like.

A display device 400 according to Embodiment 3 having a polarizing plate 100 manufactured using the laminate 10 of the present invention will be described below with reference to FIG. 11 . The display device 400 of the present embodiment is manufactured by laminating the polarizing plate 100 of the first embodiment on a liquid crystal panel as a light source side polarizing plate and a viewer side polarizing plate.

FIG. 11 is a cross-sectional view schematically showing a display device 400 according to Embodiment 3 of the present invention. As shown in FIG. 11, the display device 400 includes two substrates 410 and 420, a liquid crystal layer 430 positioned between them, polarizing plates 100 and 100 arranged outside the two substrates 410 and 420, respectively, have Two polarizing plates 100 are polarizing plates 100 manufactured using the laminate 10 of the first embodiment. As shown in FIG. 11, the two polarizing plates 100 are each laminated such that the base film 112 of the polarizing plate is arranged between the PVA resin film 111 of the polarizing plate and the liquid crystal layer 430. .

According to the present embodiment, it is possible to provide a display device including a polarizing plate that can use the base film as a protective film and that can be efficiently manufactured even if the polarizing plate is thin.

[Embodiment 4: Display device]
A display device 450 according to Embodiment 4 having the polarizing plate of the present invention will be described with reference to FIG. The display device 450 of this embodiment uses the polarizing plate of the present invention as one of the light source side polarizing plate and the viewing side polarizing plate, and is manufactured by laminating the polarizing plate on a liquid crystal panel.
FIG. 12 is a cross-sectional view schematically showing a display device 450 according to Embodiment 4 of the present invention. As shown in FIG. 12, the display device 450 includes two substrates 410 and 420, a liquid crystal layer 430 positioned between them, and a polarizing plate 120 disposed on the outer surface of the lower substrate 410 (bottom surface in the drawing). , has A polarizing plate 120 is the polarizing plate of the first modification. As shown in FIG. 12, the polarizing plate 120 is laminated such that the base film 112 of the polarizing plate is arranged between the PVA resin film 111 of the polarizing plate and the liquid crystal layer 430 .

According to this embodiment, it is possible to use the base film as a protective film, and to provide a method for manufacturing a display device equipped with the polarizing plate of the present invention, which can be efficiently manufactured even if the thickness is thin. can be done.

[Embodiment 5: Display device]
A display device 460 according to Embodiment 5 having the polarizing plate 160 of the present invention will be described with reference to FIG. The display device 460 of the present embodiment uses the polarizing plate of the present invention as one of the light source side polarizing plate and the viewer side polarizing plate, and is manufactured by laminating the polarizing plate on a liquid crystal panel.
FIG. 13 is a cross-sectional view schematically showing a display device 460 according to Embodiment 5 of the present invention. As shown in FIG. 13, the display device 460 includes two substrates 410 and 420, a liquid crystal layer 430 positioned between them, and a polarizing plate 160 disposed on the outer surface of the lower substrate 410 (bottom surface in the drawing). , has A polarizing plate 160 is the polarizing plate of the third modification. As shown in FIG. 13, the polarizing plate 160 is laminated such that the base film 112 of the polarizing plate is arranged between the PVA resin film 111 of the polarizing plate and the liquid crystal layer 430 .

According to this embodiment, it is possible to use the base film as a protective film, and to provide a method for manufacturing a display device equipped with the polarizing plate of the present invention, which can be efficiently manufactured even if the thickness is thin. can be done.

[Embodiment 6: Display device]
A polarizing plate manufactured using the laminate for polarizing plate of the present invention can be used as a material for an EL display device.
An organic EL display device usually comprises a substrate, a transparent electrode, a light emitting layer and a metal electrode layer in this order from the light emitting side, and the polarizing plate obtained by the manufacturing method of the present invention is arranged on the light emitting side of the substrate. be.
An EL display device has two substrates, a light-emitting layer positioned between them, and a polarizing plate disposed outside one of the two substrates. The display device can be produced by laminating the polarizing plate of the present invention on an organic EL panel or an inorganic EL panel.

A display device 500 according to Embodiment 6, which includes a polarizing plate manufactured using the polarizing plate laminate of the present invention, will be described below with reference to FIG. The display device 500 of this embodiment is manufactured by laminating the polarizing plate 100 of the present invention on an organic EL panel.
FIG. 14 is a cross-sectional view schematically showing a display device 500 according to Embodiment 6 of the present invention. The display device 500 has two substrates 510 and 520 , a light-emitting layer 530 positioned between them, and a polarizing plate 100 disposed on the outer surface (bottom surface in the drawing) of the lower substrate 510 . A polarizing plate 100 is the polarizing plate of the first embodiment. As shown in FIG. 14, the polarizing plate 100 is laminated such that the base film 112 of the polarizing plate 100 is arranged between the PVA resin film 111 of the polarizing plate 100 and the light-emitting layer 530 .

According to the present embodiment, it is possible to provide a display device including the polarizing plate of the present invention, which can use the base film as a protective film and can be efficiently manufactured even if it is thin.

[Embodiment 7: Display device]
A display device 550 according to Embodiment 7 having a polarizing plate manufactured using the laminate of the present invention will be described with reference to FIG. The display device 550 of this embodiment is manufactured by laminating the polarizing plate 120 of the present invention on an organic EL panel.
FIG. 15 is a cross-sectional view schematically showing a display device 550 according to Embodiment 7 of the present invention. The display device 550 has two substrates 510 and 520 , a light-emitting layer 530 positioned between them, and a polarizing plate 120 disposed on the outer surface (bottom surface in the drawing) of the lower substrate 510 . A polarizing plate 120 is the polarizing plate of the first modification. As shown in FIG. 15, the polarizing plate 120 is laminated such that the base film 112 of the polarizing plate 120 is arranged between the PVA resin film 111 of the polarizing plate 120 and the light emitting layer 530 .

According to the present embodiment, it is possible to provide a display device including the polarizing plate of the present invention, which can use the base film as a protective film and can be efficiently manufactured even if it is thin.

[Embodiment 8: Display device]
A display device 560 according to Embodiment 8 comprising a polarizing plate manufactured using the laminate of the present invention will be described with reference to FIG. The display device 560 of this embodiment is manufactured by laminating the polarizing plate 160 of the present invention on an organic EL panel.
FIG. 16 is a cross-sectional view schematically showing a display device 560 according to Embodiment 8 of the present invention. The display device 560 has two substrates 510 and 520, a light-emitting layer 530 positioned between them, and a polarizing plate 160 arranged outside (bottom side in the figure) of the lower substrate 510. FIG. A polarizing plate 160 is the polarizing plate of the third modification. As shown in FIG. 16, the polarizing plate 160 is laminated such that the base film 112 of the polarizing plate 160 is arranged between the PVA resin film 111 of the polarizing plate 160 and the light emitting layer 530 .

According to the present embodiment, it is possible to provide a display device including the polarizing plate of the present invention, which can use the base film as a protective film and can be efficiently manufactured even if it is thin.

[Other embodiments]
(1) In Embodiment 3, the polarizing plate of Embodiment 1 is used for each of the light source side polarizing plate and the viewer side polarizing plate. Alternatively, two polarizing plates of Embodiment 2 or Modifications 1 to 4 may be used.
(2) In Embodiments 4 and 5, the polarizing plate of Modification 1 and the polarizing plate of Modification 3 are used as one of the light source side polarizing plate and the viewer side polarizing plate, respectively. The polarizing plate of Embodiment 2, Modification 2, or Modification 4 may be used.
(3) Embodiments 6 to 8 show examples in which the polarizing plate of Embodiment 1, the polarizing plate of Modification 1, and the polarizing plate of Modification 3 are used in the organic EL display device, respectively, but the present invention is not limited to this. . For example, the polarizing plate of Embodiment 2, the polarizing plate of Modification 2, or the polarizing plate of Modification 4 may be used, or the polarizing plate of the present invention may be used in an inorganic EL display device.

EXAMPLES The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to the following examples. In the following, "parts" and "%" regarding the quantitative ratios of components represent parts by weight unless otherwise specified.

〔Evaluation methods〕
[Weight average molecular weight (Mw) and molecular weight distribution (Mw/Mn]
The molecular weights of block copolymers and hydrogenated block copolymers were measured at 38° C. as standard polystyrene conversion values by GPC using THF as an eluent. As a measuring device, HLC8020GPC manufactured by Tosoh Corporation was used.

[Hydrogenation rate]
The hydrogenation rate of the hydrogenated block copolymer was calculated by ¹ H-NMR spectrum or GPC analysis. The region of hydrogenation rate of 99% or less was calculated by measuring ¹ H-NMR spectrum, and the region of over 99% was calculated by GPC analysis from the peak area ratio by UV detector and RI detector.

[Measurement of MFR (melt flow rate measured at 190°C and a load of 2.16 kg)]
The melt flow rate was measured according to JIS K7210 using an extrusion plastometer (manufactured by Tateyama Kagaku Kogyo Co., Ltd., trade name "Melt Indexer (L240)") under the conditions of a temperature of 190°C and a load of 2.16 kg. It was measured.

[Measurement of tensile modulus]
The tensile modulus was measured according to JIS K7127 using a tensile tester (manufactured by Instron Japan Company Limited, trade name "Electromechanical universal material testing machine (5564)") by the following method.
The substrate film was punched into a test piece type 1B shape described in JIS K7127, and the stress when the test piece was stretched in the long side direction and distorted was measured. The stress measurement conditions were a temperature of 23° C., a humidity of 60±5% RH, a distance between chucks of 115 mm, and a tensile speed of 50 mm/min. Stress measurements were performed five times. From the measured stress and the measurement data of the strain corresponding to the stress, the strain of the test piece is in the range of 0.6% to 1.2%. Measurement data at 0.6%, 0.8%, 1.0% and 1.2%) is selected, and the least squares method is performed from the measurement data of 4 points of 5 measurements (total 20 points) was used to calculate the tensile modulus.

[Method for measuring phase difference]
The in-plane retardation Re1 of the polyvinyl alcohol resin film, the in-plane retardation Re2 of the stretched material of the base film, and the in-plane retardation of the base film in the polarizing plate were measured using a phase difference meter (Inc. It was measured using Optoscience Co., Ltd., trade name "Mueller Matrix Polarimeter (Axo Scan)"). The measurement wavelength was set to 550 nm for the measurement.
The retardation in the in-plane direction of the base film generated when the laminate is uniaxially stretched at the free end at a temperature of 50 ° C. and the laminate at a temperature of 120 ° C. is 6.0 times. If both retardations in the in-plane direction of the substrate film generated when the free end is uniaxially stretched are within the range of 0 nm or more and 20 nm or less, the laminate is heated at a temperature of 50 ° C. to 120 ° C., and 6.0 It was determined that the retardation Re2 in the in-plane direction of the substrate film, which occurs when the free-end uniaxial stretching was doubled, was 0 nm or more and 20 nm or less.

[Method for measuring thickness]
The thickness of each film (polyvinyl alcohol resin film and base film) contained in the laminate and the thickness of each film contained in the polarizing plate were measured using a thickness meter (manufactured by Mitutoyo Co., Ltd., trade name "ABS Digimatic Thickness Gauge (547 -401)”) was used to measure five times, and the average value was taken as the thickness of each film.

[Evaluation of Adhesion]
In the process up to the second stretching treatment in the production of the polarizing plate of each example, A indicates that no separation occurred between the polyvinyl alcohol resin film and the base film, and B indicates that partial separation was observed. , and C was completely peeled off.

[Evaluation of drying process]
When the polarizer was dried at 70° C. for 5 minutes in the production of the polarizing plate of each example, the polarizer was rated A when cracks did not occur, and rated C when the cracks occurred.

[Black color shift]
Manufactured in Examples and Comparative Examples by removing the liquid crystal display panel from the liquid crystal display device (manufactured by LG Electronics Japan, trade name “IPS panel monitor (23MP47)”) and peeling off the polarizing plate arranged on the viewing side. The resulting polarizing plates were laminated so that the base film was on the panel side. Further, a single polarizer without a protective film was pasted next to the polarizing plates produced in Examples and Comparative Examples, and the liquid crystal display device was reassembled. The polarizing plates prepared in Examples and Comparative Examples and the polarizer alone without a protective film were stuck together so that the absorption axis thereof was in the same direction as the absorption axis of the polarizing plate before peeling.
When the direction of the absorption axis of the polarizing plate placed on the viewing side is 0° in azimuth and the vertical direction of the panel is 0° in polar angle, the panel is in a black display state (that is, black color is displayed on the entire display screen of the panel). 45° in azimuth and 45° in polar angle. The one with a large change was judged as C.

[Example 1]
(1-1) Preparation of Polymer X Referring to the production example described in JP-A-2002-105151, after polymerizing 25 parts of styrene monomer in the first stage, 30 parts of styrene monomer and After polymerizing 25 parts of an isoprene monomer and then polymerizing 20 parts of a styrene monomer in the third stage to obtain a block copolymer [D1], the block copolymer is hydrogenated to obtain a block copolymer hydride [ E1] was synthesized. The hydrogenated block copolymer [E1] had an Mw of 84,500, an Mw/Mn of 1.20, and a hydrogenation rate of the main chain and aromatic ring of almost 100%.
Block copolymer hydride [E1] 100 parts, as an antioxidant pentaerythrityl tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (manufactured by Matsubara Sangyo Co., Ltd., product (named "Songnox 1010") was melt-kneaded and blended, and then pelletized to obtain a polymer X for molding.

(1-2) Production of base film After dissolving the polymer X produced in (1-1) in cyclohexane, 40 parts by weight of polyisobutene (manufactured by JX Nippon Oil & Energy Co., Ltd.) per 100 parts by weight of polymer X "Nisseki Polybutene HV-300", number average molecular weight 1,400), and 0.1 parts by weight of an organosilicon compound (3-aminopropyltriethoxysilane, KBM903, manufactured by Shin-Etsu Chemical Co., Ltd.) are added to form a cast film. was prepared.
The resulting film-forming coating liquid was applied to a separator film ("MRV38" manufactured by Mitsubishi Chemical Corporation) using a die coater and dried. As a result, a long base film containing the polymer X having a width of 650 mm, a length of 500 m and a thickness of 10 μm was obtained. The base film had an MFR of 10 g/10 minutes and a tensile modulus of 600 MPa.

(1-3) Production of laminate 100 parts by weight of water, polyvinyl alcohol-based adhesive ("Z-200" manufactured by Nippon Synthetic Chemical Co., Ltd.) 3 parts by weight, and cross-linking agent ("SPM-01" manufactured by Nippon Synthetic Chemical Co., Ltd.) 0.3 parts by weight were mixed to obtain an adhesive. This adhesive was applied to one surface of the base film produced in (1-2), and an unstretched polyvinyl alcohol resin film (average degree of polymerization of about 2400, saponification degree of 99.9 mol%, width of 650 mm, 20 μm thick, hereinafter also referred to as “PVA20”). In this state, the adhesive was dried by heating at 70° C. for 5 minutes to obtain a laminate.
The thickness of the substrate film, the thickness of the polyvinyl alcohol resin film, the in-plane retardation Re1, and the retardation Re2 of the obtained laminate were measured. The results are listed in Table 1. The temperature conditions for the free-end uniaxial stretching were 50°C and 120°C.

(1-4) Production of Polarizing Plate The laminate produced in (1-3) was subjected to the following operations while being continuously transported in the longitudinal direction via guide rolls.
The laminate was subjected to a swelling treatment of immersing it in water, a dyeing treatment of immersing it in a dyeing solution containing iodine and potassium iodide, and a first stretching treatment of stretching the dyed laminate. Next, the laminate after the first stretching treatment was subjected to a second stretching treatment in which the laminate was stretched in a bath containing boric acid and potassium iodide. The total draw ratio represented by the product of the draw ratio in the first drawing treatment and the draw ratio in the second drawing treatment was set to 6.0. 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.
Adhesion was evaluated in the steps up to the second stretching treatment, drying process properties were evaluated in the drying step, and the obtained polarizing plate was evaluated for black color shift. Table 1 shows the evaluation results.
Also, the thickness and retardation of the base film and the thickness of the polyvinyl alcohol resin film in the obtained polarizing plate were measured. Table 1 shows the measurement results.

[Example 2]
In (1-2) of Example 1, 0.1 parts by weight of an organic titanium compound (tetraisopropyl titanate, ORGATICS TA-8, manufactured by Matsumoto Fine Chemical Co., Ltd.) was added instead of 0.1 parts by weight of the organic silicon compound. A laminate and a polarizing plate were produced in the same manner as in Example 1, except that the base film obtained by the addition was used, and evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 3]
In (1-2) of Example 1, 0.1 parts by weight of an organic zirconium compound (N-propyl zirconate, Orgatics ZA-45, manufactured by Matsumoto Fine Chemical Co., Ltd.) was used in place of 0.1 parts by weight of the organic silicon compound. A laminate and a polarizing plate were prepared in the same manner as in Example 1 except that a base film obtained by adding was used, and evaluated in the same manner as in Example 1. Table 1 shows the results.

[Example 4]
In (1-2) of Example 1, when the film-forming coating solution was applied to the separator film using a die coater and dried, the coating amount and the like were adjusted to obtain a long film having a thickness of 5 μm. A laminate and a polarizing plate were prepared in the same manner as in Example 1, except that a base film (width and length were the same as in Example 1) was produced, and evaluation was performed in the same manner as in Example 1. . Table 1 shows the results.

[Example 5]
A laminate and a polarizing plate were produced and evaluated in the same manner as in Example 1, except that polyisobutene was not used in (1-2) of Example 1. Table 2 shows the results. The base film used in Example 5 had an MFR of 3 g/10 minutes and a tensile modulus of elasticity of 800 MPa.

[Example 6]
In (1-2) of Example 1, the organosilicon compound was not used, and the film-forming coating solution was applied to the separator film using a die coater and dried. A laminate and a polarizing plate were prepared in the same manner as in Example 1, except that a long base film having a thickness of 5 μm (the width and length were the same as those in Example 1) was produced, Evaluation was performed in the same manner as in Example 1. Table 2 shows the results.

[Comparative Example 1]
In (1-4) of Example 1, the same operation as in (1-4) was performed using only an unstretched polyvinyl alcohol resin film (PVA20) instead of the laminate produced in (1-3). As a result, fusing occurred frequently in the first stretching process and the second stretching process, and breakage occurred frequently in the drying process, so adhesion and black color shift could not be evaluated.

[Comparative Example 2]
In (1-3) of Example 1, instead of the base film produced in (1-2), a cycloolefin resin film having an elastic modulus of 2300 MPa (Zeonor Film, manufactured by Nippon Zeon, thickness 13 μm, temperature 190 ° C., A laminate was produced in the same manner as in Example 1, except that the MFR at a load of 2.16 kg was not measurable). When the laminate was subjected to the same operation as in Example 1 (1-4), breakage occurred in the first stretching treatment, and a polarizing plate could not be produced.

Tables 1 and 2 show the evaluation results of Examples and Comparative Examples.
In the table, "COP" means cycloolefin resin.
In the table, "Re2 (50 ° C.)" means the retardation in the in-plane direction of the base film generated when the laminate is uniaxially stretched 6.0 times at the free end under a temperature condition of 50 ° C. "Re2 (120°C)" means the retardation in the in-plane direction of the base film that occurs when the laminate is uniaxially stretched 6.0 times at the free end under a temperature condition of 120°C.
In the table, "Re1" means the in-plane retardation of the polyvinyl alcohol resin film in the laminate.

From the results of Tables 1 and 2, according to the present invention, the retardation that appears in the base film after the step of stretching the laminate can be reduced, and the adhesion, drying processability, and optical properties It can be seen that an excellent polarizing plate can be obtained. Thus, the base film can also be used as a protective film, and the laminate for a polarizing plate that can be efficiently manufactured even if the thickness is thin, the polarizing plate and the display device using the laminate, and the polarizing plate It can be seen that a manufacturing method can be provided.

10, 15... Laminated body (laminated body for polarizing plate)
11... Polyvinyl alcohol resin film (PVA resin film)
Reference Signs List 12 Base film 13 Adhesive layer 100, 120, 130, 150, 160, 170 Polarizing plate 111 Polyvinyl alcohol resin film (PVA resin film)
DESCRIPTION OF SYMBOLS 112... Base film 113, 114... Adhesive layer 115... Protective film 116... Adhesive layer 200... Manufacturing apparatus 201, 202... Feeding apparatus 203... Winding apparatus 205... Bonding apparatus 300... Manufacturing apparatus 301, 307... Feeding Devices 302 to 305 Processing devices 306, 309 Drying device 308 Bonding device 310 Winding device 400, 450, 460 Display device (liquid crystal display device)
410, 420... Substrate 430... Liquid crystal layer 500, 550, 560... Display device (organic EL display device)
510, 520... Substrate 530... Light-emitting layer

Claims (12)

A polarizing plate laminate comprising an unstretched polyvinyl alcohol resin film and a base film,
The polyvinyl alcohol resin film has an in-plane retardation Re1 of 50 nm or less and a thickness T of 45 μm or less,
The base film is a film made of resin,
The resin has a melt flow rate of 1 g/10 minutes or more, and the melt flow rate is a value measured at 190 ° C. and a load of 2.16 kg,
The resin has a tensile modulus E of 50 MPa or more and 1200 MPa or less,
The resin contains an organometallic compound, and the proportion of the organometallic compound is 0.005 parts by weight or more and 1.0 parts by weight or less with respect to 100 parts by weight of the resin,
The retardation Re2 in the in-plane direction of the stretched product of the base film is 0 nm or more and 20 nm or less, and the retardation Re2 is 6.0 times the polarizing plate laminate under a temperature condition of 50 ° C. to 120 ° C. The retardation of the stretched product when the free end is uniaxially stretched and the base film is used as the stretched product,
The resin is a cycloolefin resin,
The cycloolefin-based resin contains a cycloolefin-based polymer,
a polymer block [A] in which the cycloolefin-based polymer comprises a repeating unit [I] derived from an aromatic vinyl compound as a main component;
A polymer block [B] containing, as main components, a repeating unit [I] derived from an aromatic vinyl compound and a repeating unit [II] derived from a chain conjugated diene compound, or a repeating unit [II] derived from a chain conjugated diene compound, a polymer block [C] as a main component;
A block copolymer [D] consisting of
A laminate for a polarizing plate, which is a hydrogenated block copolymer hydride. 2. The polarizing plate laminate according to claim 1, wherein the cycloolefin resin contains a plasticizer, a softener, or both. 3. The polarizing plate laminate according to claim 2, wherein said plasticizer, said softener, or both of them are one or more selected from an ester plasticizer and an aliphatic hydrocarbon polymer. 4. The polarizing plate laminate according to claim 1 , wherein the base film is laminated on the polyvinyl alcohol resin film via an adhesive layer. A polarizing plate obtained by uniaxially stretching the polarizing plate laminate according to any one of claims 1 to 4 . 6. The polarizing plate according to claim 5 , wherein the surface of the polyvinyl alcohol resin film of the polarizing plate on which the base film is not laminated has a protective film or an adhesive. 7. The polarizing plate according to claim 6 , wherein the protective film is made of one or more resins selected from cycloolefin resins, acrylic resins, polyethylene terephthalate resins, and triacetylcellulose resins. two substrates and a liquid crystal layer positioned between them;
and the polarizing plate according to any one of claims 5 to 7 arranged outside at least one of the two substrates. two substrates and a light-emitting layer positioned therebetween;
and a polarizing plate according to any one of claims 5 to 7 arranged outside one of the two substrates. 9. The display device according to claim 8 , wherein a base film of the polarizing plate is provided between the polyvinyl alcohol resin film of the polarizing plate and the liquid crystal layer. 10. The display device according to claim 9 , wherein a base film of the polarizing plate is provided between the polyvinyl alcohol resin film of the polarizing plate and the light-emitting layer. A method for producing a polarizing plate, comprising the step of uniaxially stretching the polarizing plate laminate according to any one of claims 1 to 4 .

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