Classifications

• • 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
  • 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
  • B29C55/023—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets using multilayered plates or sheets
• • 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
• • 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
• • 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
• • 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
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2029/00—Use of polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals or derivatives thereof as moulding material
  • B29K2029/04—PVOH, i.e. polyvinyl alcohol
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
  • B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
  • B29K2995/00—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds
  • B29K2995/0018—Properties of moulding materials, reinforcements, fillers, preformed parts or moulds having particular optical properties, e.g. fluorescent or phosphorescent
  • B29K2995/0034—Polarising
• • 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
  • B32B2250/00—Layers arrangement
  • B32B2250/24—All layers being polymeric
• • 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
  • B32B2307/402—Coloured
  • B32B2307/4026—Coloured within the layer by addition of a colorant, e.g. pigments, dyes
• • 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

Definitions

• the present invention relates to a laminate having a thermoplastic resin film layer and a polyvinyl alcohol layer and a method for producing a polarizing film using the laminate.
• the present invention also relates to a polarizing film having a dichroic dye adsorbed on a matrix and a method for producing 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”).
• PVA Polyvinyl alcohol
• a uniaxially stretched matrix stretched film oriented by uniaxial stretching
• iodine pigment I 3 - or I 5 - etc.
• dichroic organic dye The thing which adsorb
• 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.
• thermoplastic resin film is stretched, dyed and dried after being stretched, dyed and dried on a thermoplastic resin film, and then stretched as necessary.
• a method of peeling and removing a film layer is known (see Patent Documents 1 and 2, etc.).
• 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 elution of PVA into an aqueous solution during dyeing, an insolubilization treatment is performed on the PVA layer in advance before immersing the PVA layer produced on the resin base material in the dyeing solution. Specifically, a method of dipping in an aqueous boric acid solution at room temperature is described.
• the draw ratio is more preferably 5.5 times or more, PVA having a polymerization degree of 1,000 to 10,000 is used, and the maximum draw ratio is 4.0 to It is described that it was 5.5 times.
• Patent Document 2 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 adsorbed with a dichroic substance. Thereafter, a method for producing a polarizing film by further stretching in an aqueous boric acid solution is described.
• Patent Document 2 describes a method for producing a polarizing film without insolubilizing treatment with an aqueous boric acid solution as Example 1, but in practice, crystallization in high-temperature stretching in the air at 130 ° C. in Example 1 is described. As a result, the PVA layer is insolubilized.
• Patent Document 2 describes that PVA having a polymerization degree of 1,000 or more was used.
• the present invention can suppress the elution of PVA in the step of contacting with water without performing insolubilization treatment such as immersion in boric acid aqueous solution and high temperature stretching in the air in advance, and a polarizing film having excellent polarization performance can be used as a general purpose. It aims at providing the manufacturing method of the laminated body which can be simply manufactured using a polarizing film manufacturing facility, and the polarizing film using the same.
• another object of the present invention is to provide a polarizing film having excellent polarization performance and less leakage of red light in a crossed Nicol state, and a method for producing the same.
• an unstretched laminate has a stretched laminate having a thermoplastic resin film layer and a PVA layer to produce a polarizing film.
• the degree of swelling of the PVA layer is adjusted to 180% or more and 260% or less, the 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 advance. Therefore, the insolubilization treatment, which is complicated in operation or requires special production equipment, can be omitted, and a polarizing film having excellent polarization performance can be easily produced using a general-purpose polarizing film production equipment. I found.
• the inventors of the present invention in the polarizing film in which the dichroic dye is adsorbed on the matrix, when the birefringence of the matrix is set to 45 ⁇ 10 ⁇ 3 or higher than the conventional one, the polarizing performance is excellent and the crossed nicols state is achieved. It has been found that the polarizing film has little red light leakage. Further, when a PVA layer is formed on a thermoplastic resin film to form a laminate, and a polarizing film formed on the thermoplastic resin film by uniaxially stretching the PVA layer is obtained, the average degree of polymerization is 2,800 or more. It has been found that the use of PVA of 9,500 or less improves the limit draw ratio during uniaxial stretching.
• the present invention [1] A laminate having a thermoplastic resin film layer and a PVA layer having a swelling degree of 180% or more and 260% or less (hereinafter, this may be referred to as “laminate (1)”), [2] The laminate according to [1], wherein the ethylene content of the PVA contained in the PVA layer is 1 mol% or more and 12 mol% or less.
• the present invention also provides [12] A polarizing film in which a dichroic dye is adsorbed on a matrix having a birefringence of 45 ⁇ 10 ⁇ 3 or more (hereinafter, this may be referred to as “polarizing film (2)”), [13] The polarizing film according to [12], wherein the matrix contains PVA, and the average degree of polymerization is 2,800 or more and 9,500 or less, [14] The polarizing film according to [12], wherein the matrix contains PVA, and the average degree of polymerization is 4,100 or more and 9,500 or less, [15] The polarizing film of any one of the above [12] to [14], having a thickness of 10 ⁇ m or less, [16] A method for producing a polarizing film comprising a step of stretching a laminate having a thermoplastic resin film layer and a PVA layer to 5.7 times or more, wherein the average degree of polymerization of PVA contained in the PVA layer is 2, 800 to 9,500, a manufacturing method (her
• the laminate (1) of the present invention and the method (1) for producing a polarizing film using the same 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 in advance.
• the elution of PVA can be suppressed, and a polarizing film excellent in polarizing performance can be easily manufactured using a general-purpose polarizing film manufacturing facility.
• the polarizing film (2) of the present invention is excellent in polarizing performance and has little red light leakage in a crossed Nicol state. Furthermore, according to the manufacturing method (2) of the polarizing film of the present invention, the polarizing film (2) having excellent polarization performance and less red light leakage in the crossed Nicol state can be manufactured smoothly and simply.
• the laminate (1) of the present invention has 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 within the range of 20 to 250 ⁇ m, more preferably within the range of 30 to 230 ⁇ m, and even more preferably within the range of 50 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.
• it can suppress that the tension at the time of extending
• the degree of swelling of the PVA layer of the laminate (1) of the present invention needs to be 180% or more and 260% or less, preferably 185% or more, more preferably 190% or more, It is preferably 255% or less, and more preferably 250% or less.
• the degree of swelling is higher than 260%, PVA contained in the PVA layer is eluted in the step of contacting with water at the time of producing the polarizing film when the insolubilization treatment such as immersion in boric acid aqueous solution and high temperature stretching in the air is not performed in advance. Production of the film becomes difficult.
• the swelling degree of the PVA layer in the present invention is the mass of the PVA layer after the PVA layer is immersed in distilled water at 30 ° C. for 30 minutes and then dried at 105 ° C. for 16 hours after immersion. The percentage of the value obtained by dividing. Even if the swelling degree of the PVA layer is measured in the state of the laminated body, it is preferable to measure in the state of the laminated body in consideration of operability because substantially the same value as that obtained when the PVA layer is measured alone is obtained. . Specific methods for measuring the degree of swelling of the PVA layer include the methods described later in the examples.
• the method of adjusting the swelling degree of a PVA layer by using PVA which tends to reduce the swelling degree mentioned later is preferable. Therefore, even if the laminated body which has a thermoplastic resin film layer and a PVA layer on the conditions which do not become 100 degreeC or more is prepared, the swelling degree of the said PVA layer can be easily adjusted to the said range.
• 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, 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 the 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.
• PVA that tends to lower the degree of swelling as described above is used, even if a laminate having a thermoplastic resin film layer and a PVA layer is prepared under conditions that do not exceed 100 ° C., the degree of swelling of the PVA layer falls within the above range. It can be adjusted easily.
• PVA that easily reduces the degree of swelling include PVA having an ethylene content of 1 mol% or more and 12 mol% or less.
• ethylene content means the ratio (mol%) which the number of moles of the structural unit derived from ethylene accounts with respect to the number of moles of all the structural units which comprise PVA.
• the degree of swelling can be easily reduced to the above upper limit even when drying or heat treatment after application of the stock solution as described later is performed at a low temperature.
• the degree of swelling can be easily set to the above lower limit or more. Since the degree of swelling can be easily adjusted to the range specified in the present invention, the ethylene content is preferably 1.5 mol% or more, more preferably 2.0 mol% or more, It is preferably 11.5 mol% or less, and more preferably 11 mol% or less.
• PVA having a 1,2-glycol bond content of 0.4 mol% to 1.5 mol%.
• the amount of 1,2-glycol bonds accounts for the number of moles of bonds between adjacent vinyl alcohol units bonded by 1,2-glycol bonds to the total number of moles of bonds between adjacent vinyl alcohol units.
• the ratio (mol%) is referred to and can be determined by NMR measurement.
• the 1,2-glycol bond amount is 1.5 mol% or less, the degree of swelling can be easily reduced to the above upper limit even when drying or heat treatment after application of the stock solution as described below is performed at a low temperature. it can.
• the amount of 1,2-glycol bonds is preferably 0.5 mol% or more, and preferably 0.6 mol% or more. More preferably, it is preferably 1.4 mol% or less, and more preferably 1.3 mol% or less.
• PVA having a small 1,2-glycol bond amount can be produced using a polyvinyl ester obtained by polymerizing a vinyl ester at a low temperature as a raw material.
• a PVA having a 1,2-glycol bond content of 0.4 mol% or more and 1.5 mol% or less is obtained by polymerizing a vinyl ester within a range of approximately ⁇ 50 ° C. or more and + 50 ° C. or less.
• Esters can be used as raw materials.
• the above PVA may satisfy only one of the above-described ethylene content range and 1,2-glycol bond range, or may satisfy both. That is, PVA having an ethylene content within the above range and a 1,2-glycol bond amount exceeding 1.5 mol%; an ethylene content being less than 1 mol% and a 1,2-glycol bond amount within the above range And PVA having both the ethylene content and the 1,2-glycol bond amount within the above ranges can be used as PVA that tends to reduce the degree of swelling.
• PVA in which both the ethylene content and the 1,2-glycol bond content are within the above ranges is particularly suitable when the ethylene content is relatively high and / or the 1,2-glycol bond content is relatively low. The degree of swelling of the layer may be excessively reduced.
• the drying treatment and heat treatment after the PVA layer formation are performed at a relatively low temperature, or the ethylene content Is preferably low and / or the amount of 1,2-glycol bonds is high.
• 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 average degree of polymerization is 1,000 or more, the polarizing performance of the obtained polarizing film is improved.
• 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 98 mol% or more, more preferably 98.5 mol% or more, and 99 mol% or more from the viewpoint of the polarizing performance of the obtained polarizing film. Is more preferable.
• the degree of saponification is less than 98 mol%, PVA tends to be eluted during the production process of the polarizing film, and the eluted PVA may adhere to the film and reduce the polarizing performance of the polarizing 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 preferably contains a plasticizer from the viewpoint of improving stretchability when the laminate (1) is stretched.
• 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 stretchability of the laminate (1) 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 a polarizing film. Therefore, the total amount does not always remain in the polarizing 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 content of PVA in the PVA layer is preferably in the range of 50% by mass or more and 99% by mass or less from the ease of preparation of a desired polarizing film, and the content is 75% by mass or more. More preferably, it is more preferably 80% by mass or more, particularly preferably 85% by mass or more, more preferably 98% by mass or less, and further preferably 96% by mass or less. It is preferably 95% by 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 polarizing 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 laminate (1) of 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 is suppressed in the step of contacting with water. In addition, a thin polarizing film having excellent polarization performance can be easily produced.
• the thickness of the PVA layer is thin as described above, it is possible to reduce the tension when the laminate (1) is stretched.
• the thickness of a PVA layer is 3 micrometers or more, for example.
• the polarizing film excellent in polarizing performance is obtained more simply, etc., it is a two-layer structure of one thermoplastic resin film layer and one PVA layer. It is preferable that
• the shape of the laminate (1) is not particularly limited, but a more uniform laminate can be easily produced continuously, and can also be used continuously when producing a polarizing film using the laminate. Since it can do, it is preferable that it is a long laminated body.
• the length (length in the longitudinal direction) of the long laminate is not particularly limited, and can be appropriately set according to the use of the polarizing film to be produced. For example, the range is 5 m or more and 20,000 m or less. Can be inside.
• the width of the laminate (1) is not particularly limited and can be set as appropriate according to the use of the polarizing film to be produced. However, in recent years, liquid crystal televisions and liquid crystal monitors have been increasing in screen size. If the width of the laminate (1) is 0.5 m or more, more preferably 1.0 m or more, it is suitable for these applications. On the other hand, if the width of the laminate (1) is too wide, it tends to be difficult to uniformly stretch the polarizing film when the polarizing film is produced by a practical device. Is preferably 7 m or less.
• a method for producing the laminate (1) for example, a method of forming a PVA layer on a thermoplastic resin film can be mentioned. Specifically, PVA and, if necessary, a plasticizer other than PVA such as the above-described plasticizer can be mentioned.
• thermoplastic resin film A method in which a stock solution in which other components are dissolved in a liquid medium is coated on a thermoplastic resin film and dried; PVA, a liquid medium and, if necessary, a stock solution obtained by melting and kneading other components are thermoplastic resin A method of extruding onto a film and further drying as necessary; a method of producing a PVA film containing PVA and, if necessary, further other components by a known method, and then laminating it with a thermoplastic resin film, etc. .
• thermoplastic resin film a stock solution in which PVA and, if necessary, further other components are dissolved in a liquid medium is used as a thermoplastic resin film. A method of coating 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, and 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 industrial production of the laminate 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 for the production of the laminate (1) is subjected to a hydrophilic treatment.
• a hydrophilic treatment By forming the PVA layer so as to be in contact with the hydrophilically treated surface, the adhesion between the thermoplastic resin film layer and the PVA layer is improved.
• the 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.
• 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 when the thermoplastic resin film layer stretched after stretching the laminate (1) is peeled off. 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 discharge amount represented by the following formula (1) is preferably in the range of 180 to 350 W ⁇ min / m 2 , more preferably in the range of 190 to 320 W ⁇ min / m 2 , More preferably, it is within the range of 200 to 300 W ⁇ min / m 2 .
• Discharge amount (W ⁇ min / m 2 ) Output (W / m) / Processing speed (m / min) (1)
• the glass transition temperature is below the glass transition temperature of the thermoplastic resin film. Drying at a temperature is preferred. At this time, it is preferable to use PVA that tends to lower the degree of swelling as PVA and then dry under conditions that do not exceed 100 ° C.
• PVA that tends to lower the degree of swelling as PVA and then dry under conditions that do not exceed 100 ° C.
• the drying temperature is preferably 50 ° C.
• stacked on the thermoplastic resin film layer can be obtained easily.
• the manufacturing method (1) of the polarizing film of this invention includes the process of extending
• a dichroic dye is previously contained in the PVA layer, a polarizing film on which the dichroic dye is adsorbed can be obtained by stretching the laminate (1).
• the method for containing the dichroic dye in the PVA layer is not particularly limited.
• the method of bringing the dichroic dye into contact with the PVA layer of the laminate (1) or the above-mentioned method for forming the PVA layer A method of adding a dichroic dye to the prepared stock solution in advance 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 the stretching of the laminate (1), or the laminate ( After stretching 1), the dichroic dye is adsorbed by bringing the dichroic dye into contact with the stretched film layer formed from the PVA layer (before stretching), whereby a polarizing film on which the dichroic dye is adsorbed can be obtained.
• the PVA layer of the laminate (1) before stretching the PVA layer in the course of stretching during stretching of the laminate (1); and the PVA layer after stretching the laminate (1)
• the effect of the present invention is more remarkably obtained by obtaining a polarizing film in which the dichroic dye is adsorbed by a production method including a step of bringing the dichroic dye into contact with any one of the stretched film layers; Is preferable.
• 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.
• the swelling degree of the PVA layer of the laminate (1) is in the range of 180% or more and 260% or less. Even if the insolubilization treatment such as high temperature stretching in the air is not performed in advance, the elution of PVA can be suppressed in the step of contacting with water at the time of producing the polarizing film such as dyeing. Therefore, the effect of the present invention is more remarkably exhibited when a polarizing film is produced without such insolubilization treatment in advance.
• the PVA layer of the laminate (1) before stretching; the PVA layer in the course of stretching during stretching of the laminate (1); and the PVA layer after stretching the laminate (1) When the polarizing film in which the dichroic dye is adsorbed is produced by a production method including a step of bringing the dichroic dye into contact with any of the stretched film layers, the laminate (1 ), And before the step of contacting the dichroic dye, the step of contacting with an aqueous solution containing a boron compound such as boric acid such as boric acid and borax is not included, and / or It is preferable not to include a step of stretching at a temperature of 95 ° C. or higher (more preferably, not including a step of stretching at a temperature of 50 ° C. or higher).
• the laminate (1) having a PVA layer not containing a dichroic dye is subjected to a swelling treatment and then brought into contact with the dichroic dye.
• the PVA layer is made to contain a dichroic dye, further subjected to crosslinking treatment as necessary, the obtained laminate is stretched, further subjected to fixing treatment as necessary, and dried, a series of these treatments.
• the swelling treatment can be performed by immersing the laminate (1) 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 in which the dichroic dye is adsorbed on the matrix can be obtained by bringing the dichroic dye into contact with the film layer and dyeing.
• 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 as a solution containing a dichroic dye - in the case of using a potassium iodide solution (particularly aqueous solution), since that can be efficiently adsorb iodine dye matrix, iodine is used (I 2 ) Is preferably within a range of 0.01% by mass or more and 1.0% by mass or less, and the concentration of potassium iodide (KI) used is within a range of 0.01% by mass or more and 10% by mass or less. It is preferable that The temperature of the solution containing the dichroic dye is within a range of 20 ° C. or higher and 50 ° C. or lower, particularly 25 ° C. or higher and 40 ° C. or lower because the dichroic dye can be efficiently adsorbed to the matrix. Is preferred.
• 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 (1) 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 (1) is stretched is preferably in the range of 30 ° C. or more and 90 ° C. or less, more preferably 40 ° C. or more, and further preferably 50 ° C. or more. Moreover, it is more preferable that it is 80 degrees C or less, and it is further more preferable that it is 70 degrees C or less.
• a polarizing film having excellent thickness uniformity in the width direction can be obtained.
• the draw ratio at the time of drawing the laminate (1) is preferably 5.7 times or more, more preferably 5.8 times or more, and further preferably 5.9 times or more. By making the draw ratio of the laminate (1) within the above range, a polarizing film having better polarizing performance can be obtained.
• the upper limit of the draw ratio of the laminate (1) is not particularly limited, it is preferably 8 times or less. Stretching of the laminate (1) may be performed at one time or divided into a plurality of times, but when performed in a plurality of times, the total stretching ratio obtained by multiplying the stretching ratios of the respective stretching is the above. It only has to be within the range.
• the draw ratio in this specification is based on the length of the laminated body (1) before extending
• the stretching of the laminate (1) is preferably uniaxial stretching from the viewpoint of the performance of the obtained polarizing film.
• 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.
• lateral uniaxial stretching can be performed using a tenter type stretching machine.
• the fixing treatment is mainly performed in order to strengthen the adsorption of the dichroic dye to the PVA layer or the stretched film (matrix).
• 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 polarizing film obtained by the manufacturing method (1) of the polarizing film of the present invention 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.
• the dichroic dye is adsorbed on a matrix having a birefringence of 45 ⁇ 10 ⁇ 3 or more.
• the dichroic dye may be adsorbed inside the matrix or on the surface of the matrix, but from the viewpoint of polarization performance, the dichroic dye should be adsorbed inside the matrix. Is preferred.
• a polarizing film in which a dichroic dye is adsorbed on a matrix can be used to stretch a raw film containing dichroic dye in advance, or to adsorb a dichroic dye simultaneously with the stretching of the original film. It can be produced by, for example, adsorbing a dichroic dye after the film is stretched to form a matrix.
• the polarizing film (2) of the present invention has an unconventional structure in which the birefringence of the matrix constituting it is 45 ⁇ 10 ⁇ 3 or more.
• the birefringence of the matrix is less than 45 ⁇ 10 ⁇ 3 , red light leakage increases when the two polarizing films are arranged in a crossed Nicol state, and the polarization performance is also deteriorated.
• the birefringence of the matrix constituting the polarizing film (2) is preferably 46 ⁇ 10 ⁇ 3 or more, and 47 ⁇ 10 ⁇ more preferably 3 or more, still more preferably 48 ⁇ 10 -3 or more, and particularly preferably at 49 ⁇ 10 -3 or more, and most preferably 50 ⁇ 10 -3 or more.
• the birefringence of the matrix is, for example, 60 ⁇ 10 ⁇ 3 or less.
• the birefringence of the matrix constituting the polarizing film (2) corresponds to the birefringence of the polarizing film (2) minus the birefringence based on the dichroic dye.
• the birefringence of the film can be obtained by dividing the retardation value of the film (in-plane retardation value measured by light parallel to the thickness direction of the film) by the thickness of the film. Accordingly, the birefringence of the matrix defined in the polarizing film (2) is obtained after obtaining the retardation value of the matrix corresponding to the value obtained by subtracting the retardation value based on the dichroic dye from the retardation value of the polarizing film (2). This can be determined by dividing by the thickness of the matrix (which is usually the same as the thickness of the polarizing film (2)).
• the birefringence of the matrix in the wavelength region of light generally used for measuring the retardation value of a film, the birefringence of the matrix usually has almost no wavelength dependence, while the doublet based on a dichroic dye is used. Utilizing the fact that the refractive index is highly wavelength-dependent, the birefringence of the matrix can be obtained by the following method.
• the retardation value (unit: nm) of the polarizing film (2) measured by light having a wavelength ⁇ nm is R ⁇
• the retardation value (unit: nm) of the matrix is A
• the dichroic dye by the light of wavelength ⁇
• R ⁇ A + B ⁇ (2)
• B ⁇ B ′ / ( ⁇ 2 ⁇ 600 2 ) (3)
• the following formulas (2 ′), (3 ′), (2 ′′) and (3 ′′) obtained by substituting the measurement wavelengths of 800 nm and 1000 nm respectively into ⁇ of these formulas:
• R 800 A + B 800 (2 ′)
• B 800 B ′ / (800 2 ⁇ 600 2 ) (3 ′)
• R1000 A + B1000 (2 ")
• B 1000 B ′ / (1000 2 ⁇ 600 2 ) (3 ′′) Is obtained using the measured values of R 800 and R 1000 to obtain A, which is the retard
• a matrix contains PVA and the average degree of polymerization of PVA contained in the said matrix exists in the range of 2,800-9,500.
• the polarizing film (2) of the present invention can be easily produced by adopting the method described later using PVA having such an average polymerization degree, and as a result, such a polarizing film has an average polymerization of PVA contained in the matrix. Degrees fall within the above range.
• the average degree of polymerization of PVA contained in the matrix is more preferably 3,000 or more, further preferably 4,000 or more, and 4,100 or more.
• the average degree of polymerization of PVA contained in the matrix is obtained by extracting and removing components other than PVA contained in the matrix by immersing the polarizing film (2) in an aqueous sorbitol solution and washing with water as necessary.
• PVA obtained as a product it can be determined based on the description of JIS K6726-1994, and specifically, it can be determined by the method described later in Examples.
• the content rate of PVA in a matrix is more preferably 80% by mass or more, further preferably 90% by mass or more, more preferably 99% by mass or less, and still more preferably 98% by mass or less.
• the mass of the matrix is determined by subtracting the mass of the dichroic dye from the mass of the polarizing film (2).
• the description of PVA (including the description of the degree of saponification) other than the description of the average degree of polymerization described above is the column for the description of the laminate (1).
• the description of PVA described above can be adopted as it is, and therefore redundant description is omitted here.
• PVA in a polarizing film (2) and the manufacturing method (2) of a polarizing film mentioned later it is necessary to use PVA which is easy to reduce an above-mentioned swelling degree as preferable PVA in the column of description of a laminated body (1). Not particularly.
• the thickness of the polarizing film (2) of the present invention is preferably 10 ⁇ m or less, and more preferably 8 ⁇ m or less.
• the polarizing film (2) can be suitably used in a field where a demand for thinning a mobile phone or the like is increasing.
• the thickness of a polarizing film (2) is 1 micrometer or more, for example.
• ⁇ Production Method of Polarizing Film (2) Although the method for manufacturing the polarizing film (2) of this invention is not specifically limited, The manufacturing method of a polarizing film including the process of extending
• thermoplastic resin film layer which the said laminated body used in the manufacturing method (2) of a polarizing film has, description of the thermoplastic resin film layer mentioned above in the column of description of a laminated body (1) is employ
• the average degree of polymerization of PVA contained in the PVA layer of the laminate used in the polarizing film production method (2) is in the range of 2,800 to 9,500, and the average degree of polymerization is 3, 000 or more, more preferably 4,000 or more, further preferably 4,100 or more, particularly preferably 4,500 or more, and most preferably 5,000 or more. It is preferably 9,200 or less, more preferably 8,000 or less, and further preferably 6,000 or less. In general, if the average degree of polymerization of PVA is increased, it is considered that the tension during stretching increases and the limit stretching ratio decreases, but the present inventors have developed a laminate having a thermoplastic resin film layer and a PVA layer.
• the PVA layer which the said laminated body used in the manufacturing method (2) of a polarizing film has a plasticizer from a viewpoint of the extending
• 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 the PVA layer which the said laminated body used in the manufacturing method (2) of a polarizing film has is in the range of 1 mass part or more and 15 mass parts or less with respect to 100 mass parts of PVA contained in it. It is preferable. When the content is 1 part by mass or more, the stretchability of the laminate can be further improved. On the other hand, when 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.
• content of the plasticizer in a PVA layer is 2 mass parts or more with respect to 100 mass parts of PVA.
• the reason is not clear, but the limit draw ratio is further improved. Therefore, such a content is more preferable.
• the plasticizer contained in the PVA layer is eluted when the polarizing film is manufactured, so that the total amount does not always remain in the polarizing film.
• the PVA layer of the laminate used in the method for producing a polarizing film (2) includes an antioxidant, an antifreezing agent, a pH adjusting agent, a concealing agent, an anti-coloring agent, an oil agent, and a surfactant as necessary. And the like.
• the PVA content in the PVA layer of the laminate used in the polarizing film production method (2) is in the range of 50% by mass or more and 99% by mass or less from the ease of preparation of the desired polarizing film.
• the content is preferably 75% by mass or more, more preferably 80% by mass or more, particularly preferably 85% by mass or more, and 98% by mass. More preferably, it is 96 mass% or less, More preferably, it is 95 mass% or less.
• the thickness of the PVA layer included in the laminate used in the polarizing film production method (2) is not particularly limited, and can be, for example, 100 ⁇ m or less, and a thin polarizing film can be easily prepared. It is preferable to make the PVA layer thinner. Specifically, the thickness of 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 manufacturing method (2) of the polarizing film of 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 PVA layer can be stretched at a high limit stretch ratio.
• the thickness of the PVA layer is thin as described above, it is possible to reduce the tension when the laminate is stretched. If the thickness of the PVA layer is too thin, the PVA layer has a thickness of, for example, 3 ⁇ m or more because there is a tendency for stretching breakage to occur when the laminate is stretched.
• the laminate is stretched 5.7 times or more.
• the polarizing film (2) in which the dichroic dye is adsorbed on the matrix can be obtained by stretching the laminate.
• the method for containing the dichroic dye in the PVA layer is not particularly limited.
• the method for bringing the dichroic dye into contact with the PVA layer of the laminate or the above-described stock solution for forming the PVA layer may be used.
• a method of containing a dichroic dye in advance can be appropriately employed.
• a polarizing film (2) in which the dichroic dye is adsorbed on the matrix can be obtained by bringing the dichroic dye into contact with the matrix formed from the PVA layer (before stretching).
• insolubilization treatment insolubilization treatment, swelling treatment, crosslinking treatment, fixing treatment, drying, etc. of the PVA layer are further performed as necessary. Can do.
• 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.
• a laminate having a PVA layer not containing a dichroic dye is subjected to insolubilization treatment, further subjected to swelling treatment as necessary, A dichroic dye is contained in the PVA layer by bringing the chromatic dye into contact with each other, and if necessary, a crosslinking treatment is performed.
• the obtained laminate is stretched by 5.7 times or more, and further fixed as necessary. The method of giving a process, drying, obtaining the polarizing film formed on the stretched thermoplastic resin film layer by these series of processes, and peeling the said stretched thermoplastic resin film layer is mentioned.
• the insolubilization treatment of the PVA layer is mainly performed to prevent elution of PVA contained in the PVA layer into water.
• the insolubilization treatment for example, a method of performing a heat treatment on the laminate, or a method of immersing the laminate in an aqueous solution containing one or more boron compounds such as borate such as boric acid and borax. Is mentioned.
• a method of using an aqueous solution containing a boron compound is preferable because if the laminate is subjected to a heat treatment, wrinkles may occur with the dimensional change of the thermoplastic resin film layer.
• the heat treatment can be performed at a temperature in the range of 80 ° C. or higher and 200 ° C.
• the heat treatment is preferably performed while applying tension to the laminate.
• the temperature of the aqueous solution 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.
• the time for immersing in the aqueous solution containing the boron compound is, for example, in the range of 0.1 minutes to 5 minutes. By making it within the range of 0.1 minutes or more and 5 minutes or less, it can be insolubilized efficiently.
• the concentration of the boron compound in the aqueous solution containing the boron compound is preferably 0.5% by mass or more, more preferably 1.0% by mass or more, and further preferably 1.5% by mass or more, Moreover, it is preferable that it is 6.0 mass% or less, It is more preferable that it is 5.0 mass% or less, It is further more preferable that it is 4.0 mass% or less.
• dissolution of PVA can be prevented and it can insolubilize efficiently.
• the insolubilization treatment of the PVA layer is preferably performed before the treatment for bringing the dichroic dye into contact, and further before the swelling treatment.
• the stretching method when stretching the laminate there is no particular limitation on the stretching method when stretching the laminate, and any of wet stretching and dry stretching may be used.
• wet stretching method it can be carried out in an aqueous solution containing one or more boron compounds such as boric acid and borate such as borax, or in a solution containing the above-mentioned dichroic dye. It can also be performed in a fixed treatment bath described later.
• dry stretching method stretching may be performed at room temperature, stretching may be performed while applying heat, or stretching may be performed after water absorption.
• 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 laminate needs to be stretched to 5.7 times or more, preferably stretched to 5.8 times or more, and stretched to 5.9 times or more. More preferably.
• the stretch 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 polarizing film (2) formed on the stretched thermoplastic resin film layer is obtained.
• the method of using the polarizing film in such a form is not particularly limited.
• 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.
• 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.
• the average value of the five retardation values measured with light having a wavelength of 800 nm is defined as R 800 in the above formula (2 ′), and the average value of the five retardation values measured with light having a wavelength of 1,000 nm is expressed by the above formula ( As R 1000 in 2 ′′), solve the simultaneous equations of the above formulas (2 ′), (3 ′), (2 ′′) and (3 ′′) to obtain A (unit: nm) which is a retardation value of the matrix.
• the birefringence of the matrix is obtained by dividing this by the thickness of the polarizing film (average value at 5 locations, converted to nm) measured in “Measurement of thickness of polarizing film (2)” described later. Asked.
• 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 (5) to obtain the transmittance Ts (%) of the polarizing film.
• Ts (Ts1 + Ts2) / 2 (5)
• 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.
• the transmittance of light having a wavelength of 700 nm when tilted by 45 ° with respect to the length direction of one sample and the transmittance of light having a wavelength of 700 nm when tilted by ⁇ 45 ° are measured, and the average value thereof is measured.
• T 700 % (%) was set to T 700 % (%).
• the transmittance Ts (%) obtained in the evaluation of the polarization performance is plotted on the graph with a total of five points plotted on the horizontal axis and the orthogonal transmittance T 700 ⁇ (%) of light having a wavelength of 700 nm is plotted on the vertical axis.
• the orthogonal transmittance T 700 44 44 (%) of light having a wavelength of 700 nm when the transmittance Ts (%) is 44% was determined from the approximate curve. When the T 700 44 44 (%) was low, it was evaluated that there was little leakage of red light.
• thermoplastic resin film Amorphous polyethylene terephthalate film (A-PET sheet FR thickness 150 ⁇ m, manufactured by Teijin Chemicals Ltd.) is used as the thermoplastic resin film, and the amount of discharge on one side of the thermoplastic resin film. Corona treatment was performed at 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 two-layer laminate (a long laminate having a width of 0.5 m) composed of an amorphous polyethylene terephthalate film layer and a PVA layer having a thickness of 6 ⁇ m was produced.
• the swelling degree of the PVA layer was 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.
• PVA is immersed for 1 minute in an aqueous solution containing iodine-based 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 A laminate was obtained in the same manner as in Example 1 except that the ethylene content and 1,2-glycol bond amount of PVA were as shown in Table 1, and the degree of swelling of the PVA layer was measured.
• 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 (1) 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 ethylene content of PVA was as shown in Table 1, and the degree of swelling of the PVA layer was 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.
• Example 2 A laminate was obtained in the same manner as in Example 1 except that the ethylene content of PVA was as shown in Table 1, and the degree of swelling of the PVA layer was measured. Moreover, when the polarizing film was produced from the laminated body like Example 1, since the dyeability was bad and there were spots, only the thickness (1) was measured and the polarizing performance was not evaluated. The results are shown in Table 1 together with the adopted draw ratio.
• Example 1 since the degree of swelling of the PVA layer was in the range of 180% or more and 260% or less, the insolubilization treatment such as immersion in a boric acid aqueous solution and high-temperature stretching in the air was not performed in advance. A polarizing film having excellent performance could be produced.
• Comparative Example 1 since the degree of swelling of the PVA layer was higher than 260%, PVA contained in the PVA layer was eluted at the time of manufacturing the polarizing film, and a polarizing film could not be produced. Since the swelling degree of the layer was lower than 180%, it became a patchy polarizing film.
• the PVA film was subjected to swelling treatment, dyeing, uniaxial stretching, and drying treatment in this order to produce a polarizing film. That is, the PVA film was immersed in 30 ° C. water for 1 minute. Next, PVA is immersed for 1 minute in an aqueous solution containing iodine-based pigment (concentration of iodine used: 0.3 mass%, concentration of potassium iodide used: 2.1 mass%, temperature: 30 ° C.). An iodine pigment was contained in the film.
• thermoplastic resin film Amorphous polyethylene terephthalate film (A-PET sheet FR thickness 150 ⁇ m, manufactured by Teijin Chemicals Ltd.) is used as the thermoplastic resin film, and the amount of discharge on one side of the thermoplastic resin film. Corona treatment was performed at 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 two-layer laminate (a long laminate having a width of 0.5 m) composed of an amorphous polyethylene terephthalate film layer and a PVA layer having a thickness of 6 ⁇ m was produced.
• (4) Production of Polarizing Film A polarizing film was produced by subjecting the laminate produced in (3) to insolubilization treatment, dyeing, uniaxial stretching, and drying treatment in this order. That is, as an insolubilization treatment of the PVA layer, the laminate was immersed in a boric acid aqueous solution (concentration: 3 mass%, temperature: 30 ° C.) for 1 minute.
• PVA is immersed for 1 minute in an aqueous solution containing iodine-based 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.
• the birefringence of the matrix is high, such a polarizing film has a large dichroic ratio value and excellent polarization performance, and has a value of T 700 44 44 . It can be seen that there is little leakage of red light in the small Nicole state.
• the birefringence of the matrix is low, the dichroic ratio is small and the polarization performance is inferior, and the value of T 700 ⁇ 44 is large and crossed Nicols It can be seen that there is a lot of red light leakage in the state.
• a polarizing film such as dyeing can be obtained without performing insolubilization treatment such as immersion in a boric acid aqueous solution or high-temperature stretching in the air in advance. Since the elution of PVA contained in the PVA layer can be suppressed in the process of contact with water during production, the insolubilization treatment, which is complicated and requires special production equipment, can be omitted. Thus, it becomes possible to easily manufacture a polarizing film having excellent polarizing performance using a general-purpose polarizing film manufacturing facility.
• the polarizing film (2) of the present invention is excellent in polarizing performance and has little red light leakage in a crossed Nicol state. Furthermore, according to the manufacturing method (2) of the polarizing film of the present invention, the polarizing film (2) having excellent polarization performance and less red light leakage in the crossed Nicol state can be manufactured smoothly and simply.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Optics & Photonics (AREA)
• Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Nonlinear Science (AREA)
• Mathematical Physics (AREA)
• Chemical & Material Sciences (AREA)
• Crystallography & Structural Chemistry (AREA)
• Polarising Elements (AREA)
• Laminated Bodies (AREA)

Priority Applications (3)

Applications Claiming Priority (4)

Publications (1)

Family

ID=50067945

Family Applications (1)

Country Status (5)

Cited By (7)

Families Citing this family (4)

Citations (7)

Family Cites Families (5)

• 2013
  • 2013-07-29 WO PCT/JP2013/070431 patent/WO2014024712A1/ja active Application Filing
  • 2013-07-29 CN CN201380041597.8A patent/CN104602912B/zh active Active
  • 2013-07-29 KR KR1020157003718A patent/KR102059228B1/ko active IP Right Grant
  • 2013-07-29 JP JP2014504503A patent/JP6434309B2/ja active Active
  • 2013-08-02 TW TW102127781A patent/TWI645221B/zh active
  • 2013-08-02 TW TW106102789A patent/TWI710806B/zh active

Patent Citations (7)

Also Published As

Similar Documents

Legal Events