Classifications

• • 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
  • 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
  • B32B27/06—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material
  • B32B27/08—Layered products comprising a layer of synthetic resin as the main or only constituent of a layer, which is next to another layer of the same or of a different material of synthetic resin
• • 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
  • B32B27/18—Layered products comprising a layer of synthetic resin characterised by the use of special additives
  • B32B27/22—Layered products comprising a layer of synthetic resin characterised by the use of special additives using plasticisers
• • 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
  • B32B27/306—Layered products comprising a layer of synthetic resin comprising vinyl (co)polymers; comprising acrylic (co)polymers comprising vinyl acetate or vinyl alcohol (co)polymers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/0427—Coating with only one layer of a composition containing a polymer binder
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/043—Improving the adhesiveness of the coatings per se, e.g. forming primers
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J7/00—Chemical treatment or coating of shaped articles made of macromolecular substances
  • C08J7/04—Coating
  • C08J7/056—Forming hydrophilic coatings
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B1/00—Optical elements characterised by the material of which they are made; Optical coatings for optical elements
  • G02B1/04—Optical elements characterised by the material of which they are made; Optical coatings for optical elements made of organic materials, e.g. plastics
• • 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
  • B32B2307/00—Properties of the layers or laminate
  • B32B2307/40—Properties of the layers or laminate having particular optical properties
  • B32B2307/42—Polarizing, birefringent, filtering
• • 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
  • B32B2457/00—Electrical equipment
  • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
• • 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
  • B32B2457/00—Electrical equipment
  • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
  • B32B2457/202—LCD, i.e. liquid crystal displays
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08J—WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
  • C08J2429/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
  • C08J2429/02—Homopolymers or copolymers of unsaturated alcohols
  • C08J2429/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids

Definitions

• the present invention relates to a raw film for producing an optical film having a thermoplastic resin film layer and a polyvinyl alcohol layer, and a method for producing an optical film using the same.
• a polarizing plate having a light transmission and shielding function is a basic component of a liquid crystal display (LCD) together with a liquid crystal that changes a polarization state of light.
• LCD liquid crystal display
• Many polarizing plates have a structure in which a protective film such as a cellulose triacetate (TAC) film is bonded to the surface of a polarizing film.
• TAC cellulose triacetate
• a polarizing film constituting the polarizing plate a polyvinyl alcohol film (hereinafter referred to as “polyvinyl alcohol”).
• a polarizing film can be obtained by uniaxially stretching a PVA film preliminarily containing a dichroic dye, adsorbing a dichroic dye simultaneously with uniaxial stretching of the PVA film, or dichroic after uniaxially stretching the PVA film. Manufactured by adsorbing dyes.
• LCDs are used in a wide range of devices such as small devices such as calculators and wrist watches, notebook computers, liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, in-vehicle navigation systems, mobile phones, and measuring devices used indoors and outdoors.
• small devices such as calculators and wrist watches
• notebook computers liquid crystal monitors, liquid crystal color projectors, liquid crystal televisions, in-vehicle navigation systems, mobile phones, and measuring devices used indoors and outdoors.
• thinner polarizing plates In particular, there is an increasing demand for the thickness of the polarizing film constituting the polarizing plate to be 10 ⁇ m or less.
• a laminated body formed by forming a PVA layer on one side of the thermoplastic resin film is stretched, dyed and dried, and then the stretched thermoplastic resin film layer is formed.
• a method of peeling and removing as necessary is known (see Patent Documents 1 and 2, etc.).
• PVA contained in the PVA layer does not elute in a step of contacting with water at the time of producing the polarizing film, such as dyeing. Therefore, in the conventional method, it has been essential to perform insolubilization treatment of the PVA layer in advance before the step of contacting with water such as dyeing.
• Patent Document 1 After a PVA layer is formed on a resin substrate having a thickness of at least 20 ⁇ m and a dichroic substance is adsorbed, the total draw ratio is 5 times the original length in an aqueous boric acid solution. A method for producing a polarizing film by stretching as described above is described. Patent Document 1 describes that in order to prevent the dissolution of PVA into an aqueous solution in the dyeing step, the PVA layer is previously insolubilized before the PVA layer formed on the resin substrate is immersed in the dyeing solution. Specifically, a method of immersing in an aqueous boric acid solution at room temperature is described.
• Patent Document 2 discloses that a laminate formed by forming a PVA layer on an amorphous ester thermoplastic resin base material is stretched in the air at a high temperature of 95 to 150 ° C., and then adsorbs a dichroic substance. Thereafter, a method for producing a polarizing film by further stretching in an aqueous boric acid solution is described.
• the PVA layer is insolubilized by crystallization in high-temperature stretching in the air.
• the present invention can suppress the elution of PVA in the step of contacting with water without performing insolubilization treatment such as immersion in a boric acid aqueous solution or high temperature stretching in the air, and an optical film excellent in optical performance can be used as a general-purpose optical film. It aims at providing the manufacturing method of optical films, such as a raw film for optical film manufacture which can be simply manufactured using a film manufacturing facility, and a polarizing film using the same.
• the inventors of the present invention stretch an original film for producing an optical film having a thermoplastic resin film layer and a PVA layer to produce an optical film such as a polarizing film.
• an optical film such as a polarizing film.
• by including a boron compound in advance in the PVA layer of the unstretched optical film manufacturing raw film it comes into contact with water without performing insolubilization treatment such as immersion in boric acid aqueous solution or high temperature stretching in the air.
• insolubilization treatment such as immersion in boric acid aqueous solution or high temperature stretching in the air.
• elution of PVA can be suppressed. Therefore, the above insolubilization treatment, which is complicated in operation or requires special production equipment, is omitted, and an optical film excellent in optical performance is used as a general-purpose optical film production equipment.
• the present invention was completed through further investigation based on this finding.
• the present invention [1] A raw film for producing an optical film having a thermoplastic resin film layer and a PVA layer containing a boron compound, [2] The raw film for producing an optical film according to the above [1], wherein the moisture content of the PVA layer is 10% by mass or less, [3] The raw film for producing an optical film according to the above [1] or [2], wherein the PVA layer contains a boron compound in an amount of 0.05 part by mass or more and 3 parts by mass or less in terms of boron atom with respect to 100 parts by mass of PVA [4] The raw film for producing an optical film according to any one of [1] to [3], wherein the boron compound is boric acid, [5] The raw film for producing an optical film according to any one of the above [1] to [4], wherein the average degree of polymerization of PVA contained in the PVA layer is 1,000 or more and 9,500 or less, [6] The raw film for producing an optical film according to any one of the above [1]
• the raw film for producing an optical film of the present invention in the process of contacting with water without performing insolubilization treatment such as immersion in boric acid aqueous solution or high temperature stretching in the air,
• the optical film which can suppress elution and is excellent in optical performance can be easily manufactured using general-purpose optical film manufacturing equipment.
• the raw film for producing an optical film of the present invention is a laminated film having a thermoplastic resin film layer and a PVA layer.
• the thermoplastic resin constituting the thermoplastic resin film layer include various thermoplastic resins such as polyethylene, polypropylene, polymethylpentene, polystyrene, polycarbonate, polyvinyl chloride, methacrylic resin, nylon, polyethylene terephthalate, and their heat. Examples thereof include a copolymer having a plurality of types of monomer units constituting the plastic resin.
• the thermoplastic resin film layer only one kind of thermoplastic resin may be contained, or two or more kinds of thermoplastic resins may be contained. Among these, polyethylene terephthalate is preferable and amorphous polyethylene terephthalate is more preferable because it has high heat resistance and stretchability.
• the thickness of the thermoplastic resin film layer is preferably in the range of 20 ⁇ m to 250 ⁇ m, more preferably in the range of 30 ⁇ m to 230 ⁇ m, and still more preferably in the range of 50 ⁇ m to 200 ⁇ m.
• the thickness of the thermoplastic resin film layer is 20 ⁇ m or more, wrinkles can be effectively prevented when forming the PVA layer.
• the thickness of the thermoplastic resin film layer is 250 ⁇ m or less, it is possible to suppress an excessive increase in tension when stretching the raw film for producing an optical film.
• the PVA layer of the raw film for producing an optical film of the present invention contains a boron compound.
• elution of PVA can be suppressed in the step of contacting with water without performing insolubilization treatment such as immersion in boric acid aqueous solution or high-temperature stretching in the air in the production of an optical film.
• An optical film excellent in optical performance can be easily produced using a general-purpose optical film production facility.
• Examples of the boron compound contained in the PVA layer include boric acid salts such as boric acid and sodium tetraborate, and boric acid is preferable because the effects of the present invention are more remarkable.
• the PVA layer may contain either one type of boron compound or two or more types of boron compounds.
• the PVA layer preferably contains a boron compound in an amount of 0.05 part by mass or more and 3 parts by mass or less in terms of boron atom with respect to 100 parts by mass of PVA.
• a boron compound in an amount of 0.05 parts by mass or more in terms of boron atom with respect to 100 parts by mass of PVA
• elution of PVA can be more effectively suppressed in the step of contacting with water during optical film production.
• it can prevent more effectively that the undiluted
• the PVA layer more preferably contains 0.07 parts by mass or more in terms of boron atoms with respect to 100 parts by mass of PVA. More preferably, 1 part by mass or more, more preferably 2.5 parts by mass or less, further preferably 2 parts by mass or less, particularly preferably 1.5 parts by mass or less, 1 part by mass Most preferably, it contains:
• the raw film for producing an optical film is often stored or transported in an arbitrary form such as a sheet form or a roll form. Therefore, from the viewpoint of preventing blocking during storage or transportation, the moisture content of the optical film-manufacturing raw film is preferably at a low level, unlike a film in the process of producing an optical film.
• the moisture content of the PVA layer in the raw film for producing an optical film is preferably 10% by mass or less, more preferably 9.5% by mass or less, and 8.0% by mass or less. More preferably it is.
• the said moisture content can be 1 mass% or more, for example.
• species or 2 or more types can be used.
• vinyl esters vinyl acetate is preferable from the viewpoints of ease of production of PVA, availability, cost, and the like.
• the above-mentioned polyvinyl ester may be obtained using only one or two or more kinds of vinyl esters as a monomer. It may be a copolymer of two or more kinds of vinyl esters and other monomers copolymerizable therewith.
• Examples of the other monomer copolymerizable with the vinyl ester include ⁇ -olefins having 2 to 30 carbon atoms such as ethylene, propylene, 1-butene, and isobutene; (meth) acrylic acid or a salt thereof; (Meth) methyl acrylate, (meth) ethyl acrylate, (meth) acrylate n-propyl, (meth) acrylate i-propyl, (meth) acrylate n-butyl, (meth) acrylate i-butyl, ( (Meth) acrylic acid esters such as t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, dodecyl (meth) acrylate and octadecyl (meth) acrylate; (meth) acrylamide; N-methyl ( (Meth) acrylamide, N-ethyl (meth) acrylamide, N,
• Vinyl ether vinyl cyanide such as (meth) acrylonitrile
• vinyl halide such as vinyl chloride, vinylidene chloride, vinyl fluoride, vinylidene fluoride
• Allyl compounds such as allyl acetate and allyl chloride; maleic acid or its salts, esters or acid anhydrides; itaconic acid or its salts, esters or acid anhydrides
• vinylsilyl compounds such as vinyltrimethoxysilane; unsaturated sulfonic acids be able to.
• Said polyvinyl ester can have a structural unit derived from 1 type, or 2 or more types of an above described other monomer.
• the proportion of structural units derived from the other monomers described above in the polyvinyl ester is preferably 15 mol% or less based on the number of moles of all structural units constituting the polyvinyl ester, and is preferably 10 mol%. Hereinafter, it may be 5 mol% or less.
• the other monomer described above is a monomer that may promote water solubility of the obtained PVA, such as (meth) acrylic acid or unsaturated sulfonic acid
• the proportion of structural units derived from these monomers in the polyvinyl ester is 5 mol% or less based on the number of moles of all structural units constituting the polyvinyl ester. It is preferable that it is 3 mol% or less.
• the above PVA may be modified with one or two or more types of graft copolymerizable monomers as long as the effects of the present invention are not impaired.
• the graft copolymerizable monomer include unsaturated carboxylic acids or derivatives thereof; unsaturated sulfonic acids or derivatives thereof; ⁇ -olefins having 2 to 30 carbon atoms, and the like.
• the proportion of structural units derived from the graft copolymerizable monomer in PVA (structural units in the graft modified portion) is preferably 5 mol% or less based on the number of moles of all structural units constituting PVA. .
• the above PVA may have a part of its hydroxyl group cross-linked or not cross-linked. Moreover, said PVA may react with aldehyde compounds, such as acetaldehyde and a butyraldehyde, etc. to form an acetal structure, and the said PVA does not react with these compounds and does not form an acetal structure. May be.
• aldehyde compounds such as acetaldehyde and a butyraldehyde, etc.
• the average degree of polymerization of the PVA is preferably in the range of 1,000 to 9,500, and the average degree of polymerization is more preferably 1,500 and more, and 2,000 and more. More preferably, it is more preferably 9,200 or less, and further preferably 6,000 or less.
• the optical performance such as polarization performance
• the productivity of PVA is improved.
• the average degree of polymerization of PVA used for forming the PVA layer (PVA contained in the PVA layer) can be measured according to the description of JIS K6726-1994.
• the degree of saponification of the PVA is preferably 95 mol% or more, more preferably 96 mol% or more, and more preferably 98 mol% or more from the viewpoint of the water resistance of the obtained optical film. preferable.
• the degree of saponification is less than 95 mol%, PVA is likely to be eluted during the production process of the optical film, and the eluted PVA may adhere to the film and reduce the optical performance (polarization performance, etc.) of the optical film.
• the degree of saponification of PVA refers to the total number of moles of structural units (typically vinyl ester units) that can be converted into vinyl alcohol units by saponification and the vinyl alcohol units of PVA. The proportion (mol%) occupied by the number of moles of vinyl alcohol units.
• the degree of saponification can be measured according to the description of JIS K6726-1994.
• the PVA layer may contain a plasticizer from the viewpoint of improving stretchability when stretching the raw film for producing an optical film.
• the plasticizer may include polyhydric alcohols such as ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, tetraethylene glycol, and trimethylolpropane.
• One or more of the agents can be included. Among these, glycerin is preferable from the viewpoint of the effect of improving stretchability.
• content of the plasticizer in a PVA layer exists in the range of 1 to 15 mass parts with respect to 100 mass parts of PVA contained in it.
• the content is 1 part by mass or more, the stretchability of the raw film for producing an optical film can be further improved.
• the content is 15 parts by mass or less, it is possible to prevent the PVA layer from being excessively flexible and to deteriorate the handleability, or to prevent the PVA layer from peeling off from the thermoplastic resin film layer. can do.
• the content of the plasticizer in the PVA layer is more preferably 2 parts by mass or more with respect to 100 parts by mass of PVA, further preferably 4 parts by mass or more, and particularly preferably 5 parts by mass or more.
• the plasticizer contained in a PVA layer elutes when manufacturing an optical film. Therefore, the entire amount does not always remain in the optical film.
• the PVA layer may further contain components such as an antioxidant, an antifreezing agent, a pH adjuster, a hiding agent, a coloring inhibitor, an oil agent, and a surfactant as necessary.
• the PVA content in the PVA layer depends on the plasticizer content and moisture content, but is preferably 50% by mass or more from the viewpoint of ease of preparation of the desired optical film, and 75% by mass. More preferably, it is more preferably 80% by mass or more, particularly preferably 85% by mass or more, more preferably 99% by mass or less, and 98% by mass or less. More preferably, it is 96 mass% or less, More preferably, it is 95 mass% or less.
• the thickness of the PVA layer is not particularly limited and can be, for example, 100 ⁇ m or less. However, it is preferable to make the PVA layer thin because a thin optical film can be easily prepared. Specifically, the PVA layer Is preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, and even more preferably 10 ⁇ m or less. In the present invention, since the PVA layer has the specific configuration as described above, even if the thickness of the PVA layer is reduced as described above, the elution of PVA can be suppressed in the step of contacting with water, and the optical performance (polarization) A thin optical film excellent in performance and the like can be easily produced.
• the thickness of the PVA layer is thin as described above, it is possible to reduce the tension when the optical film-producing raw film is stretched.
• the thickness of a PVA layer is 1 micrometer or more, for example.
• the shape of the original film for producing an optical film is not particularly limited, but a more uniform original film for producing an optical film can be easily produced continuously, and also when producing an optical film using the same. Since it can be used continuously, it is preferably long.
• the length (length in the longitudinal direction) of the original optical film for producing a long optical film is not particularly limited, and can be appropriately set according to the use of the produced optical film. , 000 m or less.
• the width of the raw film for producing an optical film is not particularly limited and can be set as appropriate according to the use of the produced optical film. In recent years, the screen size of liquid crystal televisions and liquid crystal monitors has been increasing. From the viewpoint, the width of the raw film for producing an optical film is preferably 0.5 m or more, more preferably 1.0 m or more, which is suitable for these applications. On the other hand, if the width of the raw film for producing an optical film is too wide, it tends to be difficult to uniformly stretch the optical film when it is produced with a device that has been put into practical use.
• the width of the anti-film is preferably 7 m or less.
• Examples of the method for producing a raw film for producing an optical film include, for example, PVA, a boron compound and, if necessary, other components (other components other than PVA and boron compound such as the above-described plasticizer) in a liquid medium.
• PVA polyvinyl alcohol
• boron compound a boron compound and, if necessary, other components (other components other than PVA and boron compound such as the above-described plasticizer) in a liquid medium.
• a method in which a stock solution dissolved in a solution is applied onto a thermoplastic resin film and dried; a stock solution obtained by melt-kneading PVA, a boron compound, a liquid medium and other components as required is extruded onto a thermoplastic resin film.
• a method of further drying as necessary a method of producing a PVA film containing PVA, a boron compound and, if necessary, further other components by a known method, and then laminating it with a thermoplastic resin film.
• a stock solution in which PVA, a boron compound and other components are further dissolved in a liquid medium is heated.
• a method of coating on a plastic resin film and drying is preferred.
• liquid medium examples include water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, N-methylpyrrolidone, ethylene glycol, glycerin, propylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol, trimethylolpropane, ethylenediamine, diethylenetriamine. Of these, one or more of these can be used. Among these, water is preferable from the viewpoint of environmental load and recoverability.
• the volatile content rate of the stock solution (the content ratio in the stock solution of volatile components such as a liquid medium that is removed by volatilization or drying during the formation of the PVA layer) varies depending on the formation method and formation conditions of the PVA layer, It is preferably in the range of 50% by mass to 98% by mass, and more preferably in the range of 55% by mass to 95% by mass.
• the volatile content of the stock solution is 50% by mass or more, its viscosity does not become too high, and filtration and defoaming during the preparation of the stock solution are smoothly performed, and formation of a PVA layer with less foreign matter and defects is facilitated. At the same time, the coatability is also improved.
• the volatile content of the stock solution is 98% by mass or less, the concentration of the stock solution does not become too low, and the industrial production of the raw film for producing an optical film is facilitated.
• Examples of the coating method for coating the stock solution on the thermoplastic resin film include a die coating method, a comma coating method, and a dip coating method.
• the die coating method is preferable from the viewpoint of the uniformity of the thickness of the obtained PVA layer.
• thermoplastic resin film used in the production of the raw film for producing an optical film is subjected to a hydrophilic treatment so that the thermoplastic resin film can be easily adhered to the PVA layer.
• hydrophilic treatment include corona treatment, plasma treatment, anchor coat treatment, and the like. Among these, corona treatment is preferable from the viewpoint of easy adjustment of hydrophilicity.
• the contact angle of the surface of the thermoplastic resin film is preferable to adjust to 55 ° or more and 70 ° or less by the hydrophilization treatment, more preferably to adjust the contact angle to 57 ° or more, and to 59 ° or more. More preferably, it is more preferably adjusted to 69 ° or less, and further preferably adjusted to 68 ° or less. If the contact angle is lower than 55 °, the adhesive strength between the thermoplastic resin film layer and the PVA layer tends to be too strong, and the stretched thermoplastic resin film layer is peeled off after stretching the original film for optical film production. In some cases, peeling may be difficult.
• the contact angle of the surface of the thermoplastic resin film is the angle formed by the water surface and the surface of the thermoplastic resin film where the free surface of water is in contact with the thermoplastic resin film (takes an angle inside the water) It can measure by the method mentioned later in an Example.
• the glass transition temperature is below the glass transition temperature of the thermoplastic resin film. Drying at a temperature is preferred.
• the specific drying temperature is not particularly limited, but in consideration of drying efficiency, it is preferably within a range of 20 ° C. or higher and 95 ° C. or lower, and the drying temperature is more preferably 50 ° C. or higher. More preferably, the temperature is more than 90 ° C, more preferably 90 ° C or less, and still more preferably 85 ° C or less.
• the original film for producing an optical film of the present invention is used as an original film for producing an optical film.
• a polarizing film, retardation film, etc. are mentioned, for example, Since the effect of this invention is show
• Such an optical film can be produced, for example, by a method using the raw film for producing an optical film of the present invention and having a step of stretching, specifically, for producing an optical film of the present invention.
• a laminate derived from the original film itself or the original film for producing an optical film of the present invention produced by applying a swelling treatment described later hereinafter referred to as “the original film for producing an optical film of the present invention”).
• the “laminated body derived from the raw film for producing an optical film of the present invention” can be collectively produced by a method having a step of stretching (sometimes abbreviated as “laminated body”).
• the dichroic dye is contained in the PVA layer in advance, the dichroic dye is adsorbed by stretching the laminate.
• a polarizing film can be obtained.
• the method for containing the dichroic dye in the PVA layer is not particularly limited. For example, a method of bringing the dichroic dye into contact with the PVA layer (PVA layer before stretching) of the laminate or a PVA layer is formed. For example, a method of previously containing a dichroic dye in the stock solution described above can be appropriately employed.
• the dichroic dye when the dichroic dye is not previously contained in the PVA layer, the dichroic dye is brought into contact with the PVA layer that is in the process of stretching during stretching of the laminate, or after the laminate is stretched A polarizing film in which the dichroic dye is adsorbed can be obtained by bringing the dichroic dye into contact with the stretched film layer formed from the PVA layer (before stretching).
• Obtaining a polarizing film in which a dichroic dye is adsorbed by a production method including a step of bringing one or two or more dichroic dyes into contact with each other has the effect of the present invention more remarkably. To preferred.
• a swelling treatment, a crosslinking treatment, a fixing treatment, drying, and the like can be further performed as necessary in addition to the treatment (dyeing) in which the drawing and dichroic dye are brought into contact.
• the order of each process may be changed as needed, each process may be performed twice or more, and different processes may be performed simultaneously.
• the process of peeling the said stretched thermoplastic resin film as needed is included. Also good.
• insolubilization treatment such as immersion in a boric acid aqueous solution or high-temperature stretching in the air.
• a manufacturing method including a step of bringing one or two or more dichroic dyes into contact with each other, an original film for producing an optical film of the present invention
• a laminate having a PVA layer not containing a dichroic dye is subjected to a swelling treatment, and then brought into contact with the dichroic dye, whereby the dichroic dye is applied to the PVA layer.
• the method of obtaining the polarizing film formed on the layer and peeling the said stretched thermoplastic resin film layer is mentioned.
• the swelling treatment can be performed by immersing the laminate in water.
• the temperature of the water when immersed in water is preferably within a range of 20 ° C. or higher and 40 ° C. or lower, more preferably 22 ° C. or higher, and further preferably 25 ° C. or higher. Moreover, it is more preferable that it is 38 degrees C or less, and it is still more preferable that it is 35 degrees C or less.
• time to immerse in water it is preferable to exist in the range of 0.1 minute or more and 5 minutes or less, and it is more preferable to exist in the range of 0.5 minute or more and 3 minutes or less.
• a PVA layer can be efficiently swollen by setting it within the range of 0.1 minute or more and 5 minutes or less.
• the water at the time of immersing in water is not limited to pure water, The aqueous solution in which various components melt
• a polarizing film on which a dichroic dye is adsorbed can be obtained by contacting the dye with a dye.
• the contact of the dichroic dye can be performed by immersing the laminated body before stretching, during stretching, or after stretching in a solution (particularly an aqueous solution) containing the dichroic dye.
• the concentration of the dichroic dye in the solution containing the dichroic dye can be appropriately set according to the type of the dichroic dye used, for example, 0.001% by mass to 1% by mass.
• iodine-potassium iodide solution especially an aqueous solution
• iodine-based dye can be adsorbed efficiently, so that the iodine (I 2 ) used
• concentration is preferably in the range of 0.01% by mass to 1.0% by mass
• concentration of potassium iodide (KI) used is in the range of 0.01% by mass to 10% by mass. It is preferable.
• the temperature of the solution containing the dichroic dye is preferably in the range of 20 ° C. or higher and 50 ° C. or lower, particularly in the range of 25 ° C. or higher and 40 ° C. or lower, because the dichroic dye can be adsorbed efficiently. .
• dichroic dye examples include iodine based dye (I 3 - and I 5 -, etc.), and the like dichroic organic dyes.
• the iodine dye can be obtained, for example, by bringing iodine (I 2 ) into contact with potassium iodide.
• dichroic organic dye examples include direct black 17, 19, 154; direct brown 44, 106, 195, 210, 223; direct red 2, 23, 28, 31, 37, 39, 79, 81, 240, 242, 247; Direct Blue 1, 15, 22, 78, 90, 98, 151, 168, 202, 236, 249, 270; Direct Violet 9, 12, 51, 98; Direct Green 1, 85; Direct Yellow 8, 12, 44, 86, 87; Direct Orange 26, 39, 106, 107 and the like.
• dichroic dyes iodine-based dyes are preferable from the viewpoints of handleability, availability, and polarization performance.
• the dichroic dye may either be two or more even alone, for example, I 3 - may be a balanced mixture as - and I 5.
• the crosslinking treatment is preferably performed after the treatment for bringing the dichroic dye into contact and before the stretching.
• the crosslinking treatment can be performed by immersing the laminate in an aqueous solution containing a crosslinking agent.
• a crosslinking agent one or more of boron compounds such as boric acid and borate such as borax can be used.
• the concentration of the crosslinking agent in the aqueous solution containing the crosslinking agent is preferably in the range of 1% by mass or more and 15% by mass or less, more preferably 2% by mass or more, and further preferably 3% by mass or more, Moreover, it is more preferable that it is 7 mass% or less, and it is further more preferable that it is 6 mass% or less. Sufficient stretchability can be maintained when the concentration of the crosslinking agent is in the range of 1% by mass to 15% by mass.
• the aqueous solution containing a crosslinking agent may contain an auxiliary agent such as potassium iodide.
• the temperature of the aqueous solution containing the crosslinking agent is preferably in the range of 20 ° C. or higher and 50 ° C. or lower, particularly in the range of 25 ° C. or higher and 40 ° C. or lower. It can bridge
• the wet stretching method is preferable from the viewpoint of the uniformity of the thickness in the width direction of the obtained polarizing film, and it is more preferable to stretch in a boric acid aqueous solution.
• the concentration of boric acid in the boric acid aqueous solution is preferably in the range of 0.5% by mass or more and 6.0% by mass or less, and the concentration is more preferably 1.0% by mass or more.
• the content is more preferably 5% by mass or more, more preferably 5.0% by mass or less, and further preferably 4.0% by mass or less.
• the aqueous solution containing the boron compound described above may contain potassium iodide, and the concentration is preferably in the range of 0.01% by mass to 10% by mass.
• concentration of potassium iodide is in the range of 0.01% by mass or more and 10% by mass or less, a polarizing film with better polarizing performance can be obtained.
• the temperature at which the laminate is stretched is preferably in the range of 30 ° C. or higher and 90 ° C. or lower, the temperature is more preferably 40 ° C. or higher, further preferably 50 ° C. or higher, 80 ° C. or lower is more preferable, and 70 ° C. or lower is further preferable.
• the temperature is in the range of 30 ° C. or higher and 90 ° C. or lower, a polarizing film having excellent thickness uniformity in the width direction can be obtained.
• the draw ratio at the time of drawing the laminate is preferably 5.7 times or more, more preferably 5.8 times or more, and further preferably 5.9 times or more.
• a polarizing film that is more excellent in polarizing performance can be obtained.
• the upper limit of the draw ratio of the laminate is not particularly limited, it is preferably 8 times or less.
• the stretching of the laminate may be performed at once or may be performed in multiple times, but when performed in multiple times, the total stretch ratio multiplied by the stretch ratio of each stretch is within the above range. I just need it.
• the draw ratio in this specification is based on the length of the laminated body before extending
• the stretching of the laminate is preferably uniaxial stretching from the viewpoint of the performance of the obtained polarizing film.
• Uniaxial stretching in the longitudinal direction is preferred. Uniaxial stretching in the longitudinal direction can be performed by changing the peripheral speed between the rolls using a stretching apparatus including a plurality of rolls parallel to each other. On the other hand, lateral uniaxial stretching can be performed using a tenter type stretching machine.
• the fixing treatment is mainly performed to strengthen the adsorption of the dichroic dye to the PVA layer or the stretched film layer.
• the fixing treatment can be performed by immersing the laminate before stretching, during stretching, or after stretching in a fixing treatment bath.
• a fixing treatment bath an aqueous solution containing one or more of boron compounds such as boric acid such as boric acid and borax can be used.
• the concentration of the boron compound in the aqueous solution containing the boron compound used as the fixing treatment bath is generally in the range of 2% by mass to 15% by mass, and particularly preferably in the range of 3% by mass to 10% by mass. .
• the temperature of the fixing treatment bath is preferably in the range of 15 ° C. or higher and 60 ° C. or lower, particularly in the range of 25 ° C. or higher and 40 ° C. or lower.
• suction of a dichroic dye can be strengthened more.
• Drying conditions are not particularly limited, but drying is preferably performed at a temperature in the range of 30 ° C. to 150 ° C., particularly in the range of 50 ° C. to 130 ° C.
• a polarizing film excellent in dimensional stability is easily obtained by drying at a temperature in the range of 30 ° C. or higher and 150 ° C. or lower.
• the stretched thermoplastic resin film layer is not peeled off, but is used as it is or optically transparent to the polarizing film side as desired. It is good also as a polarizing plate by laminating
• a cellulose triacetate (TAC) film, an acetic acid / cellulose butyrate (CAB) film, an acrylic film, a polyester film, or the like can be used.
• the adhesive for bonding include a PVA adhesive and a urethane adhesive, and a PVA adhesive is preferable.
• the thickness of the obtained polarizing film is preferably 10 ⁇ m or less, and more preferably 8 ⁇ m or less.
• the polarizing film can be suitably used in a field where demand for thinning such as a cellular phone is increasing.
• the thickness of the polarizing film is, for example, 1 ⁇ m or more.
• thermoplastic resin film Measurement of the contact angle of the surface of the thermoplastic resin film Using a “DropMaster 500” manufactured by Kyowa Interface Science Co., Ltd., in an environment of 20 ° C. and 65% RH, 2 ⁇ L of pure water from a needle having an inner diameter of 0.4 mm is used as the thermoplastic resin. The contact angle was measured by extruding onto the surface of the film.
• Measurement of the content of boron atoms in the PVA layer The measurement of the content of boron atoms in the PVA layer was performed using an ICP emission analyzer “IRIS AP” (manufactured by Thermo Fisher Scientific). The measurement sample was weighed 10 mg of the PVA layer peeled from the laminate (original film for optical film production), then burned in an oxygen flask using 20 mL of ion-exchanged water as the absorbing solution, and filtered with a 0.45 ⁇ m filter. Prepared.
• IRIS AP ICP emission analyzer
• Ts A square sample of 2 cm in the width direction of the polarizing film and 2 cm in the length direction from the center in the width direction of the polarizing film obtained in the following Examples or Comparative Examples 2 samples, using a spectrophotometer with an integrating sphere ("V7100" manufactured by JASCO Corporation), compliant with JIS Z 8722 (object color measurement method), C light source, visible light region of 2 ° field of view Measure the light transmittance when tilted by 45 ° with respect to the length direction and the light transmittance when tilted by -45 ° for one sample. Ts1 (%) was determined.
• Ts1 and Ts2 were averaged by the following formula (2) to obtain the transmittance Ts (%) of the polarizing film.
• Ts (Ts1 + Ts2) / 2 (2)
• a total of 5 points including one point based on the transmittance Ts (%) and the degree of polarization V (%) of the polarizing film obtained in each example or comparative example are plotted on the graph with V (%) as the vertical axis.
• An approximate curve was obtained, and the degree of polarization V 44 (%) when the transmittance Ts (%) was 44% was obtained from the approximate curve.
• thermoplastic resin film As a thermoplastic resin film, an amorphous polyethylene terephthalate film (A-PET sheet FR thickness 150 ⁇ m manufactured by Teijin Chemicals Ltd.) is used to discharge on one side of the thermoplastic resin film. Corona treatment was performed at an amount of 280 W ⁇ min / m 2 (output 280 W / m, treatment speed 1.0 m / min). The contact angle of the surface of the thermoplastic resin film after the corona treatment was 60 ° (the contact angle before the corona treatment was 79 °).
• a laminate having a two-layer structure composed of an amorphous polyethylene terephthalate film layer and a PVA layer having a thickness of 6 ⁇ m (an original film for manufacturing a long optical film having a width of 0.5 m) was produced.
• the moisture content of the PVA layer and the content of boron atoms were measured. The results are shown in Table 1.
• (4) Production of Polarizing Film A polarizing film was produced by subjecting the laminate produced in (3) to swelling treatment, dyeing, uniaxial stretching, and drying treatment in this order. That is, the laminate was immersed in distilled water for 1 minute as a swelling treatment.
• iodine pigment concentration of iodine used: 0.3 mass%, concentration of potassium iodide used: 2.1 mass%, temperature: 30 ° C.
• the layer contained an iodine dye.
• it was uniaxially stretched to the limit in the longitudinal direction in an aqueous boric acid solution (boric acid concentration: 4 mass%, potassium iodide concentration: 6 mass%, temperature: 65 ° C.).
• the magnification which draws and cuts by the same method in advance was confirmed, and a magnification 0.20 times lower than the cut magnification was set as the above limit.
• Examples 2 to 4 Except having changed the kind and usage-amount of the boron compound at the time of preparing a stock solution as shown in Table 1, it carried out similarly to Example 1, and obtained the laminated body, the moisture content of a PVA layer, and content of a boron atom In addition, a polarizing film (from which the stretched amorphous polyethylene terephthalate layer was peeled) was obtained from the laminate, and each measurement or evaluation of thickness and polarizing performance was performed. The results are shown in Table 1 together with the adopted draw ratio.
• Example 5 A laminate was obtained in the same manner as in Example 1 except that the drying time for producing the laminate was changed from 240 seconds to 220 seconds, and the moisture content of the PVA layer and the boron atom content were measured. Then, a polarizing film (from which the stretched amorphous polyethylene terephthalate layer was peeled) was obtained from the laminate, and each measurement or evaluation of thickness and polarizing performance was performed. The results are shown in Table 1 together with the adopted draw ratio.
• Example 1 A laminate was obtained in the same manner as in Example 1 except that the boron compound was not used when preparing the stock solution, and the moisture content of the PVA layer and the boron atom content were measured. Moreover, when it was going to produce a polarizing film from the laminated body like Example 1, since the PVA contained in the PVA layer eluted at the time of a swelling process, the polarizing film was not able to be produced. The results are shown in Table 1.

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