CN111183378B - Polarizing plate, image display device, and method for manufacturing polarizing plate - Google Patents

Polarizing plate, image display device, and method for manufacturing polarizing plate Download PDF

Info

Publication number
CN111183378B
CN111183378B CN201880064510.1A CN201880064510A CN111183378B CN 111183378 B CN111183378 B CN 111183378B CN 201880064510 A CN201880064510 A CN 201880064510A CN 111183378 B CN111183378 B CN 111183378B
Authority
CN
China
Prior art keywords
stretching
polarizing plate
polyester resin
polarizer
pva
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN201880064510.1A
Other languages
Chinese (zh)
Other versions
CN111183378A (en
Inventor
南川善则
池岛健太郎
后藤周作
德冈咲美
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nitto Denko Corp
Original Assignee
Nitto Denko Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nitto Denko Corp filed Critical Nitto Denko Corp
Publication of CN111183378A publication Critical patent/CN111183378A/en
Application granted granted Critical
Publication of CN111183378B publication Critical patent/CN111183378B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H10—SEMICONDUCTOR DEVICES; ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR
    • H10K—ORGANIC ELECTRIC SOLID-STATE DEVICES
    • H10K59/00—Integrated devices, or assemblies of multiple devices, comprising at least one organic light-emitting element covered by group H10K50/00
    • H10K59/80—Constructional details
    • H10K59/8791—Arrangements for improving contrast, e.g. preventing reflection of ambient light
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • G02B5/3041—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
    • B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
    • B29C55/04—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique
    • B29C55/06—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets uniaxial, e.g. oblique parallel with the direction of feed
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/30—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/36—Layered products comprising a layer of synthetic resin comprising polyesters
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • G—PHYSICS
    • G09—EDUCATION; CRYPTOGRAPHY; DISPLAY; ADVERTISING; SEALS
    • G09F—DISPLAYING; ADVERTISING; SIGNS; LABELS OR NAME-PLATES; SEALS
    • G09F9/00—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements
    • G09F9/30—Indicating arrangements for variable information in which the information is built-up on a support by selection or combination of individual elements in which the desired character or characters are formed by combining individual elements
    • H—ELECTRICITY
    • H05—ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR
    • H05B—ELECTRIC HEATING; ELECTRIC LIGHT SOURCES NOT OTHERWISE PROVIDED FOR; CIRCUIT ARRANGEMENTS FOR ELECTRIC LIGHT SOURCES, IN GENERAL
    • H05B33/00—Electroluminescent light sources
    • H05B33/02—Details

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Engineering & Computer Science (AREA)
  • Nonlinear Science (AREA)
  • Theoretical Computer Science (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Mechanical Engineering (AREA)
  • Polarising Elements (AREA)
  • Laminated Bodies (AREA)
  • Liquid Crystal (AREA)
  • Electroluminescent Light Sources (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)

Abstract

The invention provides a polarizing plate with small thermal shrinkage behavior and inhibited peeling. The polarizing plate comprises a polyester resin base material and a polarizer laminated on one side of the polyester resin base material, wherein the polarizer has a thickness of 10 [ mu ] m or less, and the polyester resin base material has an elastic modulus of 2.70GPa or more.

Description

Polarizing plate, image display device, and method for manufacturing polarizing plate
Technical Field
The invention relates to a polarizing plate, an image display device and a method for manufacturing the polarizing plate.
Background
There is proposed a method of forming a polyvinyl alcohol resin layer on a polyester resin substrate, and stretching and dyeing the laminate to obtain a thin polarizer (for example, patent document 1). Such a method of manufacturing a polarizer can contribute to, for example, a reduction in thickness of an image display device, and is attracting attention.
The polarizer can be used in a state of being laminated on the polyester resin base material, and in this case, the polyester resin base material is used as a protective layer of the polarizer (patent document 2). Thus, the laminate of the polyester resin base material and the polarizer can be used as a polarizing plate without attaching a protective film to the polarizer, and this can contribute to cost reduction of the image display device, for example.
Documents of the prior art
Patent document
Patent document 1: japanese patent laid-open publication No. 2000-338329
Patent document 2: japanese patent No. 4979833
Disclosure of Invention
Problems to be solved by the invention
However, when the polarizer side surface of the polarizing plate is bonded to another optical member such as a display unit or a retardation plate with an adhesive, if the polyester resin substrate has a large heat shrinkage behavior, the polarizing plate may be peeled off in a high-temperature and high-humidity environment.
The present invention has been made to solve the above-described conventional problems, and a main object of the present invention is to provide a polarizing plate having a small heat shrinkage behavior and suppressed peeling, an image display device including the polarizing plate, and a method for manufacturing the polarizing plate.
Means for solving the problems
The polarizing plate of the present invention comprises a polyester resin base material and a polarizer laminated on one side of the polyester resin base material, wherein the polarizer has a thickness of 10 [ mu ] m or less, and the polyester resin base material has an elastic modulus of 2.70GPa or more.
In one embodiment, the polarizer is laminated on one side of the polyester resin base material without an adhesive layer interposed therebetween.
In one embodiment, an easy adhesion layer is provided between the polyester resin base material and the polarizer.
In one embodiment, the polyester resin base material functions as a protective layer for the polarizer.
According to another aspect of the present invention, there is provided an image display device. The image display device has the polarizing plate.
According to another aspect of the present invention, there is provided a method of manufacturing the polarizing plate described above. The manufacturing method comprises the following steps: forming a polyvinyl alcohol resin layer on one side of the polyester resin base material to form a laminate; dyeing and stretching the laminate to form a polarizer from the polyvinyl alcohol resin layer; and heat treating the laminate of the polyester resin base material and the polarizer after the stretching, wherein a temperature of a stretching bath during the stretching is 67 ℃ or lower and a maximum heating temperature during the heat treatment is 102 ℃ or higher, or a temperature of a stretching bath during the stretching is 69 ℃ or lower and a maximum heating temperature during the heat treatment is 105 ℃ or higher.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, a polarizing plate having a small heat shrinkage behavior and suppressed peeling, an image display device including the polarizing plate, and a method for manufacturing the polarizing plate can be provided.
Drawings
Fig. 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention.
Fig. 2 is a schematic diagram showing a manufacturing step of a polarizing plate of one embodiment.
Description of the symbols
10 polarizing plate
11 polyester resin base Material
12 polarizer
Detailed Description
The following describes embodiments of the present invention, but the present invention is not limited to these embodiments.
A. Integral constitution of polarizing plate
Fig. 1 is a cross-sectional view of a polarizing plate according to an embodiment of the present invention. As shown in fig. 1, the polarizing plate 10 includes a polyester resin substrate 11 and a polarizer 12 laminated on one side of the polyester resin substrate 11. The polarizer 12 has a thickness of 10 μm or less. The polyester resin base material 11 has an elastic modulus of 2.70GPa or more. The elastic modulus of the polyester resin substrate 11 is typically measured by a nanoindentation method using an indenter (typically, a nanoindenter). More specifically, the elastic modulus (E) of the polyester-based resin substrate 11 is calculated by the following equation based on the contact rigidity S obtained from the displacement-load hysteresis curve and the projected contact area a between the indenter and the polyester-based resin substrate, which is obtained by pressing a probe (indenter) against the surface of the polyester-based resin substrate to be measured.
E＝S×π 1/2 /2A 1/2
The polarizer 12 is preferably laminated in close contact with one surface of the polyester resin base material 11 (in other words, without an adhesive layer interposed therebetween). The polarizing plate 10 preferably has an easy-adhesion layer (not shown) between the polyester resin substrate 11 and the polarizer 12. The polarizing plate 10 may have a protective film (not shown) on the side of the polarizer 12 opposite to the polyester resin substrate 11. The polyester resin base material 11 typically functions as a protective layer of the polarizer 12. In the conventional polarizing plate, when the polarizer-side surface is bonded to another optical member and placed in a high-temperature and high-humidity environment, both ends of the polarizing plate in the stretching direction may be peeled off from the optical member. In contrast, in the polarizing plate 10 of the present embodiment, when the surface on the polarizer 12 side is bonded to another optical member, the polyester resin substrate 11 has a small thermal shrinkage behavior, and peeling in a high-temperature and high-humidity environment can be suppressed.
B. Polarizer
The polarizer is substantially a polyvinyl alcohol resin layer (PVA resin layer) in which iodine is adsorbed and oriented. The thickness of the polarizer is 10 μm or less, preferably 7.5 μm or less, and more preferably 5 μm or less, as described above. On the other hand, the thickness of the polarizer is preferably 0.5 μm or more, and more preferably 1.5 μm or more. If the thickness is too thin, the optical characteristics of the polarizer to be obtained may be deteriorated. The polarizer preferably exhibits dichroism of absorption at any wavelength of 380nm to 780 nm. The monomer transmittance of the polarizer is preferably 40.0% or more, more preferably 41.0% or more, and still more preferably 42.0% or more. The degree of polarization of the polarizer is preferably 99.8% or more, more preferably 99.9% or more, and still more preferably 99.95% or more.
Any suitable PVA type resin may be used for forming the PVA type resin layer. Examples thereof include polyvinyl alcohol and ethylene-vinyl alcohol copolymers. Polyvinyl alcohol can be obtained by saponifying polyvinyl acetate. The ethylene-vinyl alcohol copolymer can be obtained by saponifying an ethylene-vinyl acetate copolymer. The saponification degree of the PVA-based resin is usually 85 mol% to 100 mol%, preferably 95.0 mol% to 99.95 mol%, and more preferably 99.0 mol% to 99.93 mol%. The degree of saponification can be determined in accordance with JIS K6726-. By using the PVA-based resin having such a saponification degree, a polarizer having excellent durability can be obtained. When the saponification degree is too high, gelation may occur.
The average polymerization degree of the PVA-based resin may be appropriately selected depending on the purpose. The average degree of polymerization is usually 1000 to 10000, preferably 1200 to 4500, and more preferably 1500 to 4300. The average polymerization degree can be determined in accordance with JIS K6726-.
C. Polyester resin base material
The polyester resin base material has an elastic modulus of 2.70GPa or more, as described above. The elastic modulus is preferably 2.70GPa to 4.50GPa, and more preferably 2.80GPa to 3.90 GPa. This can suppress shrinkage of the polyester resin substrate in a high-temperature and high-humidity environment, and as a result, peeling of the polyester resin substrate from the optical member can be suppressed when the polarizing plate is bonded to the optical member. In the method for producing a polarizing plate described later, the elastic modulus may be controlled to fall within a desired numerical range by appropriately setting the temperature of a stretching bath when stretching a laminate of a polyester resin substrate and a polyvinyl alcohol resin layer in an aqueous solution and the maximum heating temperature when heating the laminate after stretching in an aqueous solution.
As the material for forming the polyester-based resin substrate, for example, there can be used: polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polyethylene naphthalate (PEN), isophthalic acid, copolymerized PET (PET-G) containing alicyclic dicarboxylic acids or alicyclic diols containing a cyclohexane ring or the like, other polyesters, copolymers thereof, mixtures thereof, and the like. Among them, amorphous (uncrystallized) PET or copolymerized PET is preferably used. These resins are amorphous in an unstretched state and have excellent stretchability suitable for stretching at a high ratio, and can be crystallized by stretching or heating to impart heat resistance and dimensional stability. Further, the PVA-based resin can be applied and dried in an unstretched state with sufficient heat resistance.
The glass transition temperature (Tg) of the polyester-based resin substrate is preferably 170 ℃ or lower. By using such a polyester resin base material, sufficient stretchability can be ensured while suppressing crystallization of the PVA resin layer. From the viewpoints of plasticization of the polyester resin substrate with water, favorable stretching in an aqueous solution, and the like, it is more preferably 120 ℃ or lower. In one embodiment, the glass transition temperature of the polyester-based resin substrate is preferably 60 ℃ or higher. By using such a polyester-based resin substrate, when a coating liquid containing a PVA-based resin described later is applied and dried, defects such as deformation (for example, generation of unevenness, sagging, wrinkles, and the like) of the polyester-based resin substrate can be prevented. The laminate may be stretched at an appropriate temperature (for example, about 60 to 70 ℃). In another embodiment, when a coating liquid containing a PVA-based resin is applied and dried, the glass transition temperature may be lower than 60 ℃ as long as the polyester-based resin substrate is not deformed. The glass transition temperature (Tg) is a value determined according to JIS K7121.
In one embodiment, the water absorption rate of the polyester resin base material is preferably 0.2% or more, more preferably 0.3% or more. Such a polyester resin base material absorbs water, and the water functions as a plasticizer to plasticize. As a result, the tensile stress can be greatly reduced in the aqueous solution drawing, and the drawing has excellent stretchability. On the other hand, the water absorption rate of the polyester resin base material is preferably 3.0% or less, more preferably 1.0% or less. By using such a polyester resin base material, it is possible to prevent problems such as a significant decrease in dimensional stability of the polyester resin base material during production and deterioration in appearance of the resulting laminate. Further, the PVA-based resin layer can be prevented from being broken when stretched in an aqueous solution and being peeled from the polyester-based resin substrate. The water absorption is a value obtained in accordance with JIS K7209.
The thickness of the polyester resin base material is preferably 10 to 200. mu.m, more preferably 20 to 150. mu.m.
D. Protective film
As described above, the polarizing plate 10 may have a protective film on the side of the polarizer 12 opposite to the polyester resin substrate 11. Examples of the material for forming the protective film include (meth) acrylic resins, cellulose resins such as cellulose diacetate and cellulose triacetate, cycloolefin resins, olefin resins such as polypropylene, ester resins such as polyethylene terephthalate resins, polyamide resins, polycarbonate resins, and copolymer resins thereof. The thickness of the protective film is preferably 10 μm to 100 μm.
E. Easy adhesive layer
As described above, the polarizing plate 10 may have an easy adhesion layer between the polyester resin substrate 11 and the polarizer 12. The easy adhesion layer may be a layer substantially formed only of the composition for forming an easy adhesion layer, or may be a layer or a region in which the composition for forming an easy adhesion layer is mixed (including compatibility) with the material for forming a polarizer. By forming the easy adhesion layer, excellent adhesion can be obtained. The thickness of the easy adhesion layer is preferably about 0.05 μm to 1 μm. The easy adhesion layer can be confirmed by observing the cross section of the polarizing plate with a Scanning Electron Microscope (SEM), for example.
The composition for forming an easy adhesion layer preferably contains a polyvinyl alcohol component. Any suitable PVA-based resin can be used as the polyvinyl alcohol-based component. Specific examples thereof include polyvinyl alcohol and modified polyvinyl alcohol. Examples of the modified polyvinyl alcohol include polyvinyl alcohols modified with an acetoacetyl group, a carboxylic acid group, an acryloyl group and/or a carbamate group. Among these, acetoacetyl group-modified PVA is preferably used. The acetoacetyl group-modified PVA is preferably a polymer having at least a repeating unit represented by the following general formula (I).
[ chemical formula 1]
Figure BDA0002436594690000061
In the formula (I), the ratio of n to l + m + n is preferably 1% to 10%.
The average degree of polymerization of the acetoacetyl-modified PVA is preferably 1000 to 10000, more preferably 1200 to 5000. The saponification degree of the acetoacetyl group-modified PVA is preferably 97 mol% or more. The pH of a 4 wt% aqueous solution of the acetoacetyl-modified PVA is preferably 3.5 to 5.5.
The composition for forming an easy-adhesion layer may further contain a polyolefin component, a polyester component, a polyacrylic component, and the like, depending on the purpose and the like. The easy adhesion layer-forming composition preferably further contains a polyolefin component.
Any suitable polyolefin-based resin can be used for the polyolefin-based component. Examples of the olefin component as the main component of the polyolefin resin include olefin hydrocarbons having 2 to 6 carbon atoms such as ethylene, propylene, isobutylene, 1-butene, 1-pentene, and 1-hexene. These may be used alone, or two or more kinds may be used in combination. Of these, olefinic hydrocarbons having 2 to 4 carbon atoms such as ethylene, propylene, isobutylene, and 1-butene are preferably used, and ethylene is more preferably used.
The proportion of the olefin component in the monomer components constituting the polyolefin resin is preferably 50 to 95 wt%.
The polyolefin-based resin preferably contains a carboxyl group and/or an acid anhydride group thereof. The polyolefin resin can be dispersed in water, and can form an easy-adhesion layer satisfactorily. Examples of the monomer component having such a functional group include unsaturated carboxylic acids and anhydrides thereof, half esters and half amides of unsaturated dicarboxylic acids. Specific examples thereof include acrylic acid, methacrylic acid, maleic anhydride, itaconic acid, itaconic anhydride, fumaric acid, and crotonic acid. The polyolefin resin has a molecular weight of 5000 to 80000, for example.
In the easy-adhesion layer-forming composition, the blending ratio of the polyvinyl alcohol component to the polyolefin component (the former: the latter (solid component)) is preferably 5: 95-60: 40, more preferably 20: 80-50: 50. if the polyvinyl alcohol component is excessive, sufficient adhesion may not be obtained. Specifically, the peeling force required for peeling the polarizer from the polyester resin substrate may be reduced, and sufficient adhesion may not be obtained. On the other hand, if the polyvinyl alcohol component is too small, the appearance of the obtained polarizing plate may be impaired. Specifically, when the easy-adhesion layer is formed, a defect such as white turbidity of the coating film occurs, and it is difficult to obtain a polarizing plate having excellent appearance.
The composition for forming an easy-adhesion layer is preferably aqueous. The composition for forming an easy adhesion layer may contain an organic solvent. Examples of the organic solvent include ethanol and isopropanol. The concentration of the solid content of the easy adhesion layer-forming composition is preferably 1.0 to 10% by weight.
The method for applying the composition for forming an easy-adhesion layer may be any appropriate method. After the composition for forming an easy adhesion layer is applied, the applied film may be dried. The drying temperature is, for example, 50 ℃ or higher.
F. Method for manufacturing polarizing plate
The method for manufacturing a polarizing plate of the present invention includes: forming a PVA resin layer on one side of a polyester resin substrate to prepare a laminated body; dyeing and stretching the laminated body to make the PVA resin layer into a polarizer; and after the stretching, heat-treating the laminate of the polyester resin base material and the polarizer. The temperature of the stretching bath is 67 ℃ or lower and the maximum heating temperature in the heating treatment is 102 ℃ or higher, or the temperature of the stretching bath is 69 ℃ or lower and the maximum heating temperature in the heating treatment is 105 ℃ or higher.
Fig. 2 is a schematic diagram showing a manufacturing step of a polarizing plate of one embodiment. In the process of manufacturing the polarizing plate of the present embodiment, typically, the laminate 10' of the polyester-based resin substrate and the PVA-based resin layer is fed out from the feeding unit 101, immersed in the bath 110 of an aqueous boric acid solution by the rollers 111 and 112 (insolubilization treatment), and then immersed in the bath 120 of an aqueous solution of a dichroic material (iodine) and potassium iodide by the rollers 121 and 122 (dyeing treatment). Subsequently, the substrate was immersed in a bath 130 of an aqueous solution of boric acid and potassium iodide by rollers 131 and 132 (crosslinking treatment). Next, the laminate 10' is stretched (stretching treatment in an aqueous solution) by applying tension in the longitudinal direction (longitudinal direction, conveyance direction, MD direction) by rollers 141 and 142 having different speed ratios while being immersed in a stretching bath 140 of an aqueous boric acid solution, thereby forming the PVA-based resin layer into a polarizer. Next, the laminate 10' stretched in the aqueous solution is immersed in a bath 150 of an aqueous potassium iodide solution with rolls 151 and 152 (cleaning treatment), and subjected to drying treatment (not shown). Next, the laminate 10' is sent to a heating mechanism 160 and heated (heat-treated), whereby the polarizing plate 10 of the present embodiment is obtained. Then, the obtained polarizing plate 10 is wound by a winding unit 170. Although not shown, the laminate 10' may be subjected to stretching treatment in a gas atmosphere before being subjected to insolubilization treatment. The manufacturing steps shown in fig. 2 are examples, and the number and order of the above-described processes are not particularly limited.
F-1 preparation of laminate
Any suitable method can be used for forming the PVA-based resin layer on the polyester-based resin substrate. It is preferable that a coating solution containing a PVA type resin is applied to the polyester type resin substrate and dried to form a PVA type resin layer. In one embodiment, a composition for forming an easy adhesion layer is applied to a polyester resin substrate and dried to form an easy adhesion layer, and a PVA type resin layer is formed on the easy adhesion layer.
The polyester resin base material is formed as described in the above item C. The thickness of the polyester resin base material (thickness before stretching described later) is preferably 20 to 300. mu.m, and more preferably 50 to 200. mu.m. If the thickness is less than 20 μm, the PVA based resin layer may be difficult to form. If it exceeds 300 μm, for example, when stretching in an aqueous solution, it may take a long time for the polyester resin substrate to absorb water and an excessive load may be required for stretching.
The coating liquid is typically a solution obtained by dissolving the PVA-based resin in a solvent. Examples of the solvent include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, various glycols such as glycols and trimethylolpropane, and amines such as ethylenediamine and diethylenetriamine. These may be used alone, or two or more kinds may be used in combination. Of these, water is preferred. The concentration of the PVA-based resin in the solution is preferably 3 to 20 parts by weight based on 100 parts by weight of the solvent. When the resin concentration is such as described above, a uniform coating film can be formed which adheres to the polyester resin substrate. In one embodiment, the coating liquid contains a halide. Any suitable halide may be used as the halide. Examples thereof include iodide and sodium chloride. Examples of the iodide include potassium iodide, sodium iodide and lithium iodide. Of these, potassium iodide is preferred. The amount of the halide in the coating liquid is preferably 5 to 20 parts by weight based on 100 parts by weight of the PVA-based resin, and more preferably 10 to 15 parts by weight based on 100 parts by weight of the PVA-based resin. If the amount of the halide is more than 20 parts by weight based on 100 parts by weight of the PVA-based resin, the halide may bleed out, and the resulting polarizer may be cloudy. The laminate of the PVA type resin layer containing the halide and the polyester type resin substrate is stretched at a high temperature in the air (auxiliary stretching) before stretching in boric acid water, whereby the crystallization of the PVA type resin in the PVA type resin layer after the auxiliary stretching can be promoted. As a result, when the PVA type resin layer is immersed in a liquid, the alignment disorder and the decrease in alignment of the polyvinyl alcohol molecules can be suppressed more than in the case where the PVA type resin layer does not contain a halide. This improves the optical characteristics of the polarizer to be finally obtained.
Additives may be added to the coating liquid. Examples of the additives include plasticizers and surfactants. Examples of the plasticizer include polyhydric alcohols such as ethylene glycol and glycerin. Examples of the surfactant include nonionic surfactants. These additives can be used for further improving the uniformity, dyeing property and stretching property of the PVA-based resin layer to be obtained. Further, examples of the additive include an easily bondable component. By using the easily adhesive component, the adhesion between the polyester resin base and the PVA resin layer can be improved. As a result, for example, the PVA-based resin layer can be prevented from being peeled off from the polyester-based substrate, and dyeing and stretching in an aqueous solution described later can be performed satisfactorily. As the easy-to-bond component, for example, a modified PVA such as acetoacetyl-modified PVA can be used.
Any suitable method can be used for applying the coating liquid. Examples thereof include roll coating, spin coating, wire bar coating, dip coating, die coating, curtain coating, spray coating, and blade coating (e.g., doctor blade coating). The coating and drying temperature of the coating liquid is preferably 50 ℃ or higher.
The thickness of the PVA based resin layer (thickness before stretching described later) is preferably 3 to 20 μm.
Before the PVA-based resin layer is formed, the polyester-based resin substrate may be subjected to a surface treatment (for example, corona treatment), or a composition for forming an easy-adhesion layer may be applied to the polyester-based resin substrate (coating treatment). By performing such treatment, the adhesion between the polyester resin base and the PVA resin layer can be improved. As a result, for example, the PVA-based resin layer is prevented from being peeled off from the polyester-based resin substrate, and dyeing and stretching described later can be performed satisfactorily.
F-2 stretching treatment in gas atmosphere
The stretching method for assisting stretching in a gas atmosphere may be fixed-end stretching (for example, a method of stretching using a tenter) or free-end stretching (for example, a method of unidirectionally stretching a laminate by passing the laminate between rolls having different peripheral speeds). In one embodiment, the stretching treatment in a gas atmosphere includes a hot roll stretching step of stretching the laminate by utilizing a peripheral speed difference between hot rolls while conveying the laminate in the longitudinal direction thereof. The stretching treatment in a gas atmosphere typically includes a zone (zone) stretching step and a heat roller stretching step. The order of the zone stretching step and the heat roll stretching step is not limited, and the zone stretching step may be performed first, or the heat roll stretching step may be performed first. The zone stretching step may also be omitted. In one embodiment, the zone stretching step and the hot roll stretching step are performed sequentially.
The stretching temperature of the laminate may be set to any suitable value depending on the material for forming the polyester resin base material, the stretching method, and the like. The stretching temperature in the stretching treatment in the gas atmosphere is preferably not less than the glass transition temperature (Tg) of the polyester-based resin substrate, more preferably not less than the glass transition temperature (Tg) +10 ℃, and particularly preferably not less than Tg +15 ℃. On the other hand, the upper limit of the stretching temperature of the laminate is preferably 170 ℃. Stretching at such a temperature can suppress rapid progress of crystallization of the PVA type resin, and can suppress defects caused by the crystallization (for example, the PVA type resin layer is inhibited from being oriented by stretching).
F-3. insolubilization treatment
The insolubilization treatment is typically performed by immersing the PVA-based resin layer in an aqueous boric acid solution. By performing insolubilization treatment, water resistance can be imparted to the PVA-based resin layer. The concentration of the aqueous boric acid solution is preferably 1 to 4 parts by weight with respect to 100 parts by weight of water. The liquid temperature of the insolubilization bath (aqueous boric acid solution) is preferably 20 to 50 ℃. The insolubilization treatment is preferably performed before the stretching in the aqueous solution or the dyeing treatment.
F-4 dyeing treatment
The PVA-based resin layer is typically dyed by adsorbing iodine to the PVA-based resin layer. Examples of the adsorption method include: a method of immersing the PVA-based resin layer (laminate) in a dyeing solution containing iodine; a method of applying the dyeing liquid to a PVA-based resin layer; and a method of spraying the dyeing solution onto the PVA-based resin layer. A method of immersing the PVA-based resin layer (laminate) in a dyeing solution is preferably employed. This is because iodine can be adsorbed well.
The dyeing liquid is preferably an aqueous iodine solution. The amount of iodine is preferably 0.1 to 0.5 parts by weight based on 100 parts by weight of water. In order to increase the solubility of iodine in water, it is preferable to add an iodide to the aqueous iodine solution. Specific examples of the iodide are as described above. The amount of the iodide is preferably 0.02 to 20 parts by weight, more preferably 0.1 to 10 parts by weight, based on 100 parts by weight of water. In order to suppress dissolution of the PVA based resin, the dyeing liquid is preferably at a liquid temperature of 20 ℃ to 50 ℃ during dyeing. When the PVA-based resin layer is immersed in the dyeing liquid, the immersion time is preferably 5 seconds to 5 minutes in order to ensure the transmittance of the PVA-based resin layer. The dyeing conditions (concentration, liquid temperature, and immersion time) may be set so that the polarization degree or monomer transmittance of the polarizer finally obtained falls within a predetermined range. In one embodiment, the immersion time is set so that the degree of polarization of the polarizer obtained becomes 99.98% or more. In another embodiment, the immersion time is set so that the monomer transmittance of the polarizer obtained is 40% to 44%.
The dyeing treatment may be performed at any appropriate timing. Preferably before stretching in aqueous solution.
F-5. crosslinking treatment
The crosslinking treatment is typically performed by immersing the PVA-based resin layer (laminate) in an aqueous boric acid solution. By performing the crosslinking treatment, water resistance can be imparted to the PVA-based resin layer. The concentration of the aqueous boric acid solution is preferably 1 to 5 parts by weight with respect to 100 parts by weight of water. In addition, when the crosslinking treatment is performed after the dyeing treatment, it is preferable to further blend an iodide. The iodine compound can suppress elution of iodine adsorbed on the PVA-based resin layer. The amount of the iodide is preferably 1 to 5 parts by weight based on 100 parts by weight of water. Specific examples of the iodide are as described above. The liquid temperature of the crosslinking bath (aqueous boric acid solution) is preferably 20 to 60 ℃. The crosslinking treatment is preferably performed before the stretching treatment in an aqueous solution. In a preferred embodiment, the stretching treatment, the dyeing treatment and the crosslinking treatment are sequentially performed in a gas atmosphere.
F-6 stretching treatment in aqueous solution
The polarizing plate is produced by the steps including subjecting the laminate to a stretching treatment in an aqueous solution in a stretching bath, as described above. Specifically, the laminate is stretched in an aqueous solution in a direction parallel to the stretching direction of the laminate. The stretching in an aqueous solution can be performed at a temperature lower than the glass transition temperature (typically, about 80 ℃) of the polyester resin base material or the PVA resin layer, and the stretching can be performed at a high magnification while suppressing crystallization of the PVA resin layer. As a result, a polarizer having excellent optical characteristics (e.g., degree of polarization) can be produced. In the present specification, the term "parallel direction" includes the case of 0 ° ± 5.0 °, preferably 0 ° ± 3.0 °, and more preferably 0 ° ± 1.0 °.
The stretching temperature (liquid temperature of the stretching bath) in the aqueous solution is preferably 69 ℃ or lower, and more preferably 67 ℃ or lower. The lower liquid temperature limit of the stretching bath is preferably 40 c, more preferably 50 c. By setting the liquid temperature of the stretching bath within the above range, the elastic modulus of the polyester-based resin substrate can be adjusted to a value within a preferred range, in addition to the maximum heating temperature in the heating treatment described later. Further, if the temperature is as described above, the PVA-based resin layer can be stretched at a high ratio while dissolution thereof is suppressed. Specifically, as described above, the glass transition temperature (Tg) of the polyester-based resin substrate is preferably 60 ℃ or higher in view of the relationship with the formation of the PVA-based resin layer. In this case, if the stretching temperature is lower than 40 ℃, there is a possibility that the polyester resin substrate cannot be stretched well in consideration of plasticization of the polyester resin substrate by water. On the other hand, the higher the temperature of the stretching bath, the higher the solubility of the PVA-based resin layer, and there is a possibility that excellent optical characteristics cannot be obtained. The immersion time of the laminate in the stretching bath is preferably 15 seconds to 5 minutes.
The stretching treatment in the aqueous solution may be any suitable method. Specifically, the stretching may be performed at a fixed end or a free end. The stretching direction of the laminate is substantially the stretching direction (longitudinal direction) of the laminate stretched in the above-described gas atmosphere. The stretching of the laminate may be performed in one stage or may be performed in multiple stages.
The stretching in an aqueous solution is preferably performed by immersing the laminate in an aqueous boric acid solution (stretching in an aqueous boric acid solution). By using an aqueous boric acid solution as a stretching bath, the PVA-based resin layer can be provided with rigidity capable of withstanding the tension applied during stretching and water resistance not dissolving in water. Specifically, boric acid generates tetrahydroxyborate anions in an aqueous solution, and crosslinks with the PVA-based resin through hydrogen bonds. As a result, the PVA-based resin layer can be provided with rigidity and water resistance and can be stretched well, and a polarizer having excellent optical characteristics (for example, degree of polarization) can be produced.
The aqueous boric acid solution is preferably obtained by dissolving boric acid and/or a borate in a solvent, i.e., water. The boric acid concentration is preferably 1 to 10 parts by weight relative to 100 parts by weight of water. When the boric acid concentration is 1 part by weight or more, the dissolution of the PVA-based resin layer can be effectively suppressed, and a polarizer having higher characteristics can be produced. In addition to boric acid or a borate, an aqueous solution obtained by dissolving a boron compound such as borax, glyoxal, glutaraldehyde, or the like in a solvent may be used.
When a dichroic material (represented by iodine) is adsorbed on the PVA-based resin layer by dyeing treatment in advance, it is preferable to add an iodide to the stretching bath (aqueous boric acid solution). The iodine compound can be added to suppress elution of iodine adsorbed on the PVA-based resin layer. The iodide may be exemplified by: potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide, copper iodide, barium iodide, calcium iodide, tin iodide, titanium iodide, and the like. Of these, potassium iodide is preferred. The concentration of the iodide is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 8 parts by weight, based on 100 parts by weight of water.
By combining the polyester resin base material with stretching in an aqueous solution (stretching in an aqueous boric acid solution), it is possible to stretch at a high magnification and produce a polarizer having excellent optical characteristics (for example, degree of polarization). Specifically, the maximum stretching ratio is preferably 5.0 times or more, more preferably 5.5 times or more, and even more preferably 6.0 times or more, with respect to the original length of the laminate (including the stretching ratio of the laminate). In the present specification, "maximum stretching ratio" means the stretching ratio immediately before the laminate breaks, and the stretching ratio at which the laminate breaks is confirmed, and "maximum stretching ratio" means a value lower than this value by 0.2. The maximum draw ratio of the laminate using the polyester resin base material is higher when the laminate is stretched in an aqueous solution than when the laminate is stretched only by stretching in a gas atmosphere.
F-7 cleaning treatment
The cleaning treatment is typically performed by immersing the PVA-based resin layer in an aqueous potassium iodide solution. The drying temperature in the drying treatment is preferably 30 to 100 ℃.
F-8, heat treatment
The heat treatment is performed after stretching in an aqueous solution. By the heat treatment, crystallization of the polyester-based resin substrate can proceed. The heating process is typically performed by heating a transport roller disposed in the heating mechanism 160 (using a so-called hot drum roller (heating roller)) (hot drum roller heating method). In one embodiment, the heating mechanism 160 is an oven, and a heating method (oven heating method) by sending hot air into the oven may be used in combination. By using the hot drum roller heating method and the oven heating method in combination, a rapid temperature change between the hot drum rollers can be suppressed, and the shrinkage of the layered product 10' in the width direction can be easily controlled. The oven temperature of the oven is preferably 30 ℃ to 100 ℃. The heating time in the oven is preferably 1 second to 300 seconds. The wind speed of the hot wind is preferably about 10m/s to 30 m/s. The wind speed is the wind speed in the oven and can be measured by a digital anemometer of a mini-fan blade type.
By heating with a hot drum roller, curling is suppressed and a polarizer having excellent appearance can be produced. Specifically, by heating the laminate 10' in a state of being along a hot drum roller, the crystallization of the polyester-based resin substrate can be efficiently promoted to increase the crystallinity, and the crystallinity of the polyester-based resin substrate can be favorably increased even at a relatively low heating temperature. As a result, the polyester resin base material has increased rigidity and can withstand the shrinkage of the PVA type resin layer caused by heating, thereby suppressing curling. Further, since the laminate 10' can be heated while being kept flat by using the hot drum roller, not only curling but also wrinkles can be suppressed.
In the heating mechanism 160, a plurality of heat drum rollers may be arranged, and the respective heat drum rollers may be set to different temperatures. In the heating mechanism 160, 2 to 20 hot drum rollers may be disposed, and 4 to 10 hot drum rollers are preferably disposed. The contact time (total contact time) of the laminate 10' with the hot drum roller is preferably 1 second to 300 seconds. The heating conditions can be controlled by adjusting the temperature of the hot drum rollers, the number of hot drum rollers, the contact time with the hot drum rollers, and the like.
When the temperature of the heat drum roller set to the highest temperature among the plurality of heat drum rollers is defined as "the highest heating temperature", the highest heating temperature is 102 ℃ or higher, more preferably 105 ℃ or higher, and still more preferably 110 ℃ or higher. The upper limit of the maximum heating temperature is preferably 150 c, more preferably 120 c. By setting the maximum heating temperature in the heating treatment within the above range, the durability index of the polyester-based resin substrate can be adjusted to a value within a preferable range in addition to the temperature of the stretching bath in the stretching treatment in the aqueous solution. The temperature of the hot drum roller may be measured by a contact thermometer. The contact time of the laminate with the hot drum roller kept at the maximum heating temperature (total contact time when there are a plurality of hot drum rollers at the maximum heating temperature) is preferably 0.2 to 2 seconds, more preferably 0.5 to 2 seconds. The "contact time" refers to a time from any point on the laminate to separation after contacting the outer peripheral surface of the hot drum roller held at the maximum heating temperature.
G. Image display device
The polarizing plate according to the above items a to E obtained by the production method according to the above item F can be applied to an image display device such as a liquid crystal display device. Accordingly, the present invention includes an image display device using the above polarizing plate. An image display device according to an embodiment of the present invention includes the polarizing plate described in the above items a to E.
Examples
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples. The measurement method and evaluation method of each characteristic are as follows.
(1) Thickness of
Measured using a digital micrometer (manufactured by Anritsu corporation, product name "KC-351C").
(2) Modulus of elasticity
The polyester resin substrates of the polarizing plates obtained in examples and comparative examples were measured for elastic modulus by nanoindentation under the following measurement conditions using a nanoindenter (manufactured by Hysitron Inc., ltd. "Triboindenter"). Specifically, a probe (indenter) of the nanoindenter was pressed into the surface of the polarizing plate on the polyester resin substrate side, and the contact rigidity S obtained from the displacement-load hysteresis curve and the projected contact area a between the indenter and the polyester resin substrate were calculated by the following equation.
Modulus of elasticity (E) ═ S × π 1/2 /2A 1/2
(measurement conditions)
The measurement method: single press-in method
Measurement temperature: 25 deg.C
Indentation speed: about 2nm/sec
Indentation depth: about 2000nm
Probe: made of diamond, Berkovich type (triangular pyramid type)
(3) Evaluation of adhesion
The long polarizing plates obtained in examples and comparative examples were cut into 150mm (MD direction) × 200mm (TD direction) sizes to be used as evaluation samples. The polarizer side of the above-mentioned sample for evaluation was bonded to glass with an acrylic adhesive, and after storing the sample for 500 hours at 60 ℃/90% Rh, the presence or absence of peeling of the end of the sample for evaluation from the glass was confirmed. Then, if the evaluation sample is peeled from the glass, the length of the peeled portion is measured.
< example 1>
As the polyester-based resin substrate, a long amorphous ethylene isophthalate copolymer terephthalate (IPA copolymer PET) film (thickness: 100 μm, IPA modification degree: 5 mol%) was used. (degree of modification ═ ethylene isophthalate unit ]/[ ethylene terephthalate unit + ethylene isophthalate unit ])
One surface of a polyester resin substrate was subjected to corona treatment (treatment condition: 50 W.min/m) 2 ) Then, an aqueous dispersion of a modified polyolefin resin (product name "GOHSEFIMER Z200" manufactured by japan synthetic chemical industry co., ltd.) of acetoacetyl-modified polyvinyl alcohol (PVA) (product name "ARROW BASE SE 1030N" manufactured by Unitika) was mixed with pure water, and the resulting mixture (solid content concentration 4.0%) was applied to the corona-treated surface so that the thickness after drying was 2000nm, and dried at 65 ℃ for 2 minutes to form an undercoat layer. Wherein the solid component mixing ratio of the acetoacetyl modified PVA to the modified polyolefin in the mixed solution is 30: 70. subsequently, an aqueous solution comprising 90 parts by weight of PVA (polymerization degree 4200, saponification degree 99.2 mol%) and 10 parts by weight of acetoacetyl-modified PVA (product name "GOHSEFIMER Z410" manufactured by Nippon Kagaku Kogyo Co., Ltd.) and 13 parts by weight of potassium iodide per 100 parts by weight of the PVA resin was applied to the surface of the undercoat layer at 25 ℃ and dried at 60 ℃ for 3 minutes to form a PVA resin layer having a thickness of 13 μm. A laminate was produced as described above.
The obtained laminate was subjected to uniaxial stretching with the free end extending 2 times in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds in an oven at 140 ℃ (auxiliary stretching in a gas atmosphere).
Next, the laminate was immersed in an insolubilization bath (aqueous boric acid solution containing 4 parts by weight of boric acid per 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (insolubilization treatment).
Then, the resultant was immersed in a dyeing bath (aqueous iodine solution containing 0.2 parts by weight of iodine and 1.5 parts by weight of potassium iodide based on 100 parts by weight of water) at a liquid temperature of 30 ℃ for 60 seconds (dyeing treatment).
Subsequently, the resultant was immersed in a crosslinking bath (aqueous boric acid solution containing 3 parts by weight of potassium iodide and 5 parts by weight of boric acid based on 100 parts by weight of water) at a liquid temperature of 40 ℃ for 30 seconds (crosslinking treatment).
Then, the laminate was uniaxially stretched 2.75 times (total stretching ratio: 5.5 times) in the longitudinal direction (longitudinal direction) between rolls having different peripheral speeds while being immersed in a stretching bath (stretching bath temperature: 67 ℃) of an aqueous boric acid solution (an aqueous solution prepared by mixing 3 parts by weight of boric acid and 5 parts by weight of potassium iodide with respect to 100 parts by weight of water) (stretching treatment in an aqueous solution).
Then, the laminate was immersed in a cleaning bath (aqueous solution containing 3.5 parts by weight of potassium iodide per 100 parts by weight of water) at a liquid temperature of 30 ℃ (cleaning treatment).
Then, in an oven having a plurality of heating rollers maintained at 80 to 110 ℃ and maintained at 80 ℃, the laminate is subjected to a heat treatment while being conveyed by the heating rollers so that the contact time between the laminate and the heating roller maintained at the maximum heating temperature of 110 ℃ is 1 second in total.
Thus, a long polarizing plate 1 in which polarizers having a thickness of 5 μm were laminated on a polyester resin base material was obtained. The elastic modulus of the polyester resin substrate of the polarizing plate 1 was 3.15 GPa. After the polarizing plate 1 was subjected to the adhesion evaluation, peeling from the glass did not occur.
< example 2>
A polarizing plate 2 was obtained in the same manner as in example 1, except that the maximum heating temperature was set to 105 ℃. The polyester resin substrate of the polarizing plate 2 had an elastic modulus of 2.85 GPa. The polarizing plate 2 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< example 3>
A polarizing plate 3 was obtained in the same manner as in example 1, except that the maximum heating temperature was set to 102 ℃. The polyester resin substrate of the polarizing plate 3 had an elastic modulus of 2.70 GPa. The polarizing plate 3 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< example 4>
A polarizing plate 4 was obtained in the same manner as in example 1, except that the laminated body was stretched in an aqueous solution using a stretching bath having a stretching bath temperature of 69 ℃. The elastic modulus of the polyester resin substrate of the polarizing plate 4 was 2.72 GPa. The polarizing plate 4 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< comparative example 1>
A polarizing plate 5 was obtained in the same manner as in example 1, except that the maximum heating temperature was set to 100 ℃. The elastic modulus of the polyester resin substrate of the polarizing plate 5 was 2.65 GPa. The polarizing plate 5 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< comparative example 2>
A polarizing plate 6 was obtained in the same manner as in example 1, except that the maximum heating temperature was 95 ℃. The polyester resin substrate of the polarizing plate 6 had an elastic modulus of 2.37 GPa. The polarizing plate 6 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< comparative example 3>
A polarizing plate 7 was obtained in the same manner as in example 1, except that the furnace temperature was set to 60 ℃, the maximum heating temperature was set to 60 ℃, and the total contact time was set to 1 second. The elastic modulus of the polyester resin substrate of the polarizing plate 7 was 2.10 GPa. The polarizing plate 7 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< comparative example 4>
A polarizing plate 8 was obtained in the same manner as in example 4, except that the maximum heating temperature was set to 102 ℃. The elastic modulus of the polyester resin substrate of the polarizing plate 8 was 2.57 GPa. The polarizing plate 8 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
< comparative example 5>
A polarizing plate 9 was obtained in the same manner as in example 4, except that the maximum heating temperature was set to 100 ℃. The elastic modulus of the polyester resin substrate of the polarizing plate 9 was 2.50 GPa. The polarizing plate 9 was subjected to the same evaluation as in example 1. The results are shown in Table 1.
[ Table 1]
Stretching bath temperature Maximum heating temperature Modulus of elasticity Length of peel
Example 1 67℃ 110℃ 3.15GPa 0mm
Example 2 67℃ 105℃ 2.85GPa 0mm
Example 3 67℃ 102℃ 2.70GPa 0mm
Example 4 69℃ 105℃ 2.72GPa 0mm
Comparative example 1 67℃ 100℃ 2.65GPa 1.0mm
Comparative example 2 67℃ 95℃ 2.37GPa 5.5mm
Comparative example 3 67℃ 60℃ 2.10GPa 13.5mm
Comparative example 4 69℃ 102℃ 2.57GPa 2.0mm
Comparative example 5 69℃ 100℃ 2.50GPa 3.0mm
As is clear from table 1, the polarizing plate having an elastic modulus of 2.70GPa or more does not peel from the glass even when placed in a high-temperature and high-humidity environment.
Industrial applicability
The polarizing plate of the present invention can be suitably used for image display devices such as liquid crystal display devices and organic EL display devices.

Claims (5)

1. A method for producing a polarizing plate having a polyester resin base material and a polarizer laminated on one side of the polyester resin base material,
the thickness of the polarizer is less than 10 μm,
the polyester resin base material has an elastic modulus of 2.70GPa or more,
the method comprises the following steps:
forming a polyvinyl alcohol resin layer on one side of the polyester resin base material to form a laminate;
dyeing and stretching the laminated body to make the polyvinyl alcohol resin layer into a polarizer; and
after the stretching, the laminate of the polyester resin base material and the polarizer is subjected to a heat treatment,
wherein,
the temperature of the stretching bath during the stretching is 67 ℃ or lower, and the maximum heating temperature during the heating treatment is 102 ℃ or higher, or
Wherein the temperature of a stretching bath during the stretching is 69 ℃ or lower and the maximum heating temperature during the heating treatment is 105 ℃ or higher,
the time for holding at the maximum heating temperature is 0.2 seconds to 2 seconds.
2. The polarizing plate production method according to claim 1, wherein,
the polarizer is laminated on one side of the polyester resin substrate without an adhesive layer interposed therebetween.
3. The polarizing plate production method according to claim 1, wherein,
an easy adhesion layer is arranged between the polyester resin base material and the polarizer.
4. The method for manufacturing a polarizing plate according to any one of claims 1 to 3,
the polyester resin base material functions as a protective layer of the polarizer.
5. A method for manufacturing an image display device, comprising the method for manufacturing a polarizing plate according to any one of claims 1 to 4.
CN201880064510.1A 2017-10-03 2018-09-26 Polarizing plate, image display device, and method for manufacturing polarizing plate Active CN111183378B (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2017193274A JP7240090B2 (en) 2017-10-03 2017-10-03 Polarizing plate, image display device, and method for manufacturing polarizing plate
JP2017-193274 2017-10-03
PCT/JP2018/035613 WO2019069755A1 (en) 2017-10-03 2018-09-26 Polarizing plate, image display device, and production method for polarizing plate

Publications (2)

Publication Number Publication Date
CN111183378A CN111183378A (en) 2020-05-19
CN111183378B true CN111183378B (en) 2022-09-27

Family

ID=65994677

Family Applications (1)

Application Number Title Priority Date Filing Date
CN201880064510.1A Active CN111183378B (en) 2017-10-03 2018-09-26 Polarizing plate, image display device, and method for manufacturing polarizing plate

Country Status (4)

Country Link
JP (1) JP7240090B2 (en)
CN (1) CN111183378B (en)
TW (1) TWI771503B (en)
WO (1) WO2019069755A1 (en)

Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002040243A (en) * 2000-07-19 2002-02-06 Fuji Photo Film Co Ltd Circularly polarizing plate, touch panel and reflective liquid crystal display device
JP2003043257A (en) * 2001-08-01 2003-02-13 Sumitomo Chem Co Ltd Method for manufacturing polarizing film and polarizing film
JP2003154616A (en) * 2001-11-20 2003-05-27 Teijin Dupont Films Japan Ltd Laminated film and surface protective film
CN1831568A (en) * 2005-03-09 2006-09-13 柯尼卡美能达精密光学株式会社 Anti-glare film, manufacturing method of anti-glare film, anti glaring anti-reflection film, polarizing plate, and display
CN1973218A (en) * 2004-08-19 2007-05-30 日东电工株式会社 Phase difference plate with protective film, method for manufacture thereof, pressure-sensitive adhesion type phase difference plate with protective film and pressure-sensitive adhesion type optical m
JP2008162108A (en) * 2006-12-28 2008-07-17 Nippon Polyethylene Kk Surface protective film
CN103472519A (en) * 2012-06-06 2013-12-25 日东电工株式会社 Polarizing film including modified PVA, and optical laminate with the polarizing film
JP2014095880A (en) * 2012-10-04 2014-05-22 Fujifilm Corp Optical film, phase difference film, polarizing plate, and liquid crystal display device
CN104062701A (en) * 2013-03-19 2014-09-24 日东电工株式会社 Method Of Producing Polarizing Plate
CN104635288A (en) * 2013-11-06 2015-05-20 富士胶片株式会社 Polarizer manufacturing method
CN106019419A (en) * 2015-03-31 2016-10-12 住友化学株式会社 Laminated film, manufacturing method of laminated film, manufacturing method of polarized laminated film, and manufacturing method of polaroid
CN106163764A (en) * 2014-03-31 2016-11-23 株式会社可乐丽 Biaxially oriented film and manufacture method, polarizer protecting film, decorating film and laminate film
KR20170027558A (en) * 2015-09-02 2017-03-10 주식회사 엘지화학 Manufacturing method for thin polarizer, thin polarizer manufactured by thereof, polarizing plate and display device comprising thereof
CN106597594A (en) * 2015-10-14 2017-04-26 日东电工株式会社 Polarizing plate and manufacturing method thereof
JP2017078155A (en) * 2015-05-21 2017-04-27 株式会社巴川製紙所 Protective film, film laminate and polarizing plate
WO2017145607A1 (en) * 2016-02-26 2017-08-31 日東電工株式会社 Polarizer, one-side-protected polarizing film, polarizing film including adhesive layer, and image display device and method for continuously manufacturing same

Family Cites Families (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP4279944B2 (en) * 1999-06-01 2009-06-17 株式会社サンリッツ Manufacturing method of polarizing plate
JP2002303725A (en) * 2001-04-06 2002-10-18 Nitto Denko Corp Polarizing film, optical film and liquid crystal display device both using the polarizing film
WO2004081090A1 (en) * 2003-03-11 2004-09-23 Mitsubishi Polyester Film Corporation Biaxially oriented polyester film and release film
JP4759317B2 (en) * 2005-05-26 2011-08-31 富士フイルム株式会社 Polarizing plate and liquid crystal display device using the same
JP2008003541A (en) * 2006-01-27 2008-01-10 Fujifilm Corp Polarizer protective film, and polarizer and liquid crystal display using the same
KR101833579B1 (en) * 2010-12-02 2018-02-28 닛토덴코 가부시키가이샤 Method of manufacturing polarizing plate
JP6144548B2 (en) * 2012-08-01 2017-06-07 日東電工株式会社 Transparent conductive laminated film, method for producing the same, and touch panel
JPWO2014057949A1 (en) * 2012-10-12 2016-09-05 富士フイルム株式会社 Liquid crystal display
JP6127490B2 (en) * 2012-12-11 2017-05-17 東亞合成株式会社 Polarizer
TW201428011A (en) * 2012-12-11 2014-07-16 Toagosei Co Ltd Active-energy-ray-curable composition for forming optical film, optical film, and polarizing plate
JP6096582B2 (en) * 2013-04-19 2017-03-15 富士フイルム株式会社 Polarizing plate, method for manufacturing the same, and image display device
KR101555782B1 (en) * 2013-06-18 2015-09-24 주식회사 엘지화학 Thin polarizing plate and method for maunfacturing the same
JPWO2015001980A1 (en) * 2013-07-01 2017-02-23 コニカミノルタ株式会社 Polarizing plate and liquid crystal display device using the same
JPWO2015076101A1 (en) * 2013-11-19 2017-03-16 コニカミノルタ株式会社 Polarizing plate and liquid crystal display device using the same
JP6138755B2 (en) 2014-12-24 2017-05-31 日東電工株式会社 Polarizer
KR102569041B1 (en) * 2015-05-27 2023-08-21 미츠비시 가스 가가쿠 가부시키가이샤 Polyester resin and manufacturing method thereof
KR101803675B1 (en) * 2016-01-19 2017-11-30 스미또모 가가꾸 가부시키가이샤 Polarizing plate and image display device
JP6893762B2 (en) * 2016-03-04 2021-06-23 日東電工株式会社 Polarizer
JP7240091B2 (en) * 2017-10-03 2023-03-15 日東電工株式会社 Polarizing plate, image display device, and method for manufacturing polarizing plate

Patent Citations (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2002040243A (en) * 2000-07-19 2002-02-06 Fuji Photo Film Co Ltd Circularly polarizing plate, touch panel and reflective liquid crystal display device
JP2003043257A (en) * 2001-08-01 2003-02-13 Sumitomo Chem Co Ltd Method for manufacturing polarizing film and polarizing film
JP2003154616A (en) * 2001-11-20 2003-05-27 Teijin Dupont Films Japan Ltd Laminated film and surface protective film
CN1973218A (en) * 2004-08-19 2007-05-30 日东电工株式会社 Phase difference plate with protective film, method for manufacture thereof, pressure-sensitive adhesion type phase difference plate with protective film and pressure-sensitive adhesion type optical m
CN1831568A (en) * 2005-03-09 2006-09-13 柯尼卡美能达精密光学株式会社 Anti-glare film, manufacturing method of anti-glare film, anti glaring anti-reflection film, polarizing plate, and display
JP2008162108A (en) * 2006-12-28 2008-07-17 Nippon Polyethylene Kk Surface protective film
CN103472519A (en) * 2012-06-06 2013-12-25 日东电工株式会社 Polarizing film including modified PVA, and optical laminate with the polarizing film
JP2014095880A (en) * 2012-10-04 2014-05-22 Fujifilm Corp Optical film, phase difference film, polarizing plate, and liquid crystal display device
CN104062701A (en) * 2013-03-19 2014-09-24 日东电工株式会社 Method Of Producing Polarizing Plate
CN104635288A (en) * 2013-11-06 2015-05-20 富士胶片株式会社 Polarizer manufacturing method
CN106163764A (en) * 2014-03-31 2016-11-23 株式会社可乐丽 Biaxially oriented film and manufacture method, polarizer protecting film, decorating film and laminate film
CN106019419A (en) * 2015-03-31 2016-10-12 住友化学株式会社 Laminated film, manufacturing method of laminated film, manufacturing method of polarized laminated film, and manufacturing method of polaroid
JP2017078155A (en) * 2015-05-21 2017-04-27 株式会社巴川製紙所 Protective film, film laminate and polarizing plate
KR20170027558A (en) * 2015-09-02 2017-03-10 주식회사 엘지화학 Manufacturing method for thin polarizer, thin polarizer manufactured by thereof, polarizing plate and display device comprising thereof
CN106597594A (en) * 2015-10-14 2017-04-26 日东电工株式会社 Polarizing plate and manufacturing method thereof
WO2017145607A1 (en) * 2016-02-26 2017-08-31 日東電工株式会社 Polarizer, one-side-protected polarizing film, polarizing film including adhesive layer, and image display device and method for continuously manufacturing same

Non-Patent Citations (1)

* Cited by examiner, † Cited by third party
Title
《浇注料在不同加热过程中的弹性模量变化》;陈风毅 等;《耐火材料》;20141231;144-146 *

Also Published As

Publication number Publication date
CN111183378A (en) 2020-05-19
JP7240090B2 (en) 2023-03-15
TW201935047A (en) 2019-09-01
TWI771503B (en) 2022-07-21
KR20200064078A (en) 2020-06-05
JP2019066715A (en) 2019-04-25
WO2019069755A1 (en) 2019-04-11

Similar Documents

Publication Publication Date Title
CN108780172B (en) Polarizing plate
CN111164473B (en) Polarizing plate, image display device, and method for manufacturing polarizing plate
CN108780171B (en) Polarizing plate
CN111183380A (en) Polarizing plate, image display device, and method for manufacturing polarizing plate
JP6921953B2 (en) Laminates, methods for manufacturing laminates, polarizing plates, and methods for manufacturing polarizing plates
KR102640210B1 (en) Polarizer, image display device and method of manufacturing polarizer
CN111183378B (en) Polarizing plate, image display device, and method for manufacturing polarizing plate
KR102716823B1 (en) Polarizing plate, image display device and method for manufacturing polarizing plate
KR102718408B1 (en) Polarizing plate, image display device and method for manufacturing polarizing plate
TWI857940B (en) Polarizing plate, image display device, and method for manufacturing polarizing plate
JP7083612B2 (en) Manufacturing method of optical laminate
CN115989138A (en) Optical laminate and method for manufacturing polarizing plate using same

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant