CN103442871B - Polymer film of polyvinyl alcohol and manufacture method thereof - Google Patents

Polymer film of polyvinyl alcohol and manufacture method thereof Download PDF

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Publication number
CN103442871B
CN103442871B CN201280015847.6A CN201280015847A CN103442871B CN 103442871 B CN103442871 B CN 103442871B CN 201280015847 A CN201280015847 A CN 201280015847A CN 103442871 B CN103442871 B CN 103442871B
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film
pva
dryer roll
polymer film
ratio
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CN103442871A (en
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森保二郎
风藤修
日笠慎太郎
胜野良治
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Kuraray Co Ltd
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Kuraray Co Ltd
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    • 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
    • C08J5/00—Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18—Manufacture of films 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
    • B29C41/00—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/24—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length
    • B29C41/26—Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor for making articles of indefinite length by depositing flowable material on a rotating drum
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • 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
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3083—Birefringent or phase retarding elements

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Optics & Photonics (AREA)
  • Manufacturing & Machinery (AREA)
  • Mechanical Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Mathematical Physics (AREA)
  • Materials Engineering (AREA)
  • Medicinal Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Health & Medical Sciences (AREA)
  • Polarising Elements (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Liquid Crystal (AREA)
  • Shaping By String And By Release Of Stress In Plastics And The Like (AREA)
  • Moulding By Coating Moulds (AREA)

Abstract

The present invention is the manufacture method of PVA film and film, and wherein, described PVA film is the PVA film that the productivity ratio of draftability and polarizing coating is good, meet following formula (I) and (II); Δ n (MD) Ave-0.1 × 10 -3≤ Δ n (TD) Ave≤Δ n (MD) Ave+0.25 × 10 -3(I) Δ n (TD) Ave≤2.5 × 10 -3(II) [in formula, Δ n (MD) Ave represents the birefringence of the length direction of PVA film equalization and the value obtained on the thickness direction of film, and Δ n (TD) Ave represents the birefringence of the width of PVA film equalization and the value obtained on the thickness direction of film]; In the manufacture method of described film, the masking stoste containing PVA spues to the first dryer roll of the film forming apparatus possessing many dryer rolls and after carrying out part drying with membranaceous by (a), carries out drying to manufacture successively with follow-up dryer roll; Now, the peripheral speed (S of the dryer roll when volatile ingredient ratio of (b) PVA film reaches 13 quality % t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 0.990 ~ 1.050; Peripheral speed (the S of (c) final dryer roll l) relative to peripheral speed (S t) ratio (S l/ S t) be 0.960 ~ 0.980; (d) ratio (S l/ S 1) be 0.970 ~ 1.010.

Description

Polymer film of polyvinyl alcohol and manufacture method thereof
Technical field
The polarizing coating that the present invention relates to polymer film of polyvinyl alcohol (Off ィ Le system) and manufacture method thereof and be made up of this film.In more detail, there is high limit stretching ratio with high magnification stretched film also not easy fracture, the polarizing coating that the interruption of stretching operation etc. can not occur with the fracture of film, can the polymer film of polyvinyl alcohol of the stretched film of the excellent in optical properties such as polarization property and manufacture method thereof be manufactured with high finished product rate, good productivity ratio and be made up of this film even if the present invention relates to.
Background technology
The liquid crystal etc. of the polarizer with the transmission of light and function of shielding and the switching function with light is all the important inscape of liquid crystal indicator (LCD).The application of this liquid crystal indicator also from the miniature instruments such as calculator during initial stage of development and wrist-watch expand to notebook computer, LCDs, color liquid crystal projecting apparatus, LCD TV, onboard navigation system, mobile phone, in doors the vast scope such as the metrical instrument that uses, particularly in LCDs, LCD TV etc., the positive development of large screen.
The general manufacture as described below of polarizer: by the method for process of carrying out with iodine, dichroic dye after by polymer film of polyvinyl alcohol uniaxial tension dyeing, by polymer film of polyvinyl alcohol dyeing and the method being fixed process after uniaxial tension with boron compound, the method etc. that is fixed process in dyeing in any one method above-mentioned manufacture polarizing coating, at the diaphragm such as one or both sides laminating tri cellulose acetate membrane, cellulose acetate butyrate (CAB) film etc. of the polarizing coating obtained thus simultaneously.
In recent years, along with the expansion etc. of the purposes of liquid crystal indicator, except display quality advanced except, also require the further reduction of cost and the further raising of treatability.From the viewpoint of what reduce costs, need to improve speed of production when manufacturing polarizing coating, and need the tension failure (fracture) prevented when being stretched by polymer film of polyvinyl alcohol, reduce fracture loss, improve yield rate, and the interruption etc. of the stretching operation preventing the fracture with film and produce, stretching-dyeing operation.
As a kind of method of the raising of productivity ratio during manufacture polarizing coating, require the shortening of drying time when manufacturing polarizing coating, from this viewpoint, as the former film (former anti-Off ィ Le system) of polarizing coating, generally use thickness was the polymer film of polyvinyl alcohol of about 75 μm in the past, but in recent years, the polymer film of polyvinyl alcohol of thinner than 70 μm, the further filming of required thickness.
But, there is the problem that polymer film of polyvinyl alcohol more easily occurs when more Bao Ze stretches with high magnification to rupture, from this viewpoint, even if require the polymer film of polyvinyl alcohol that ultimate elongation multiplying power highly very thinly also to stretch with high magnification in cases where no fracturing is occurring, thus can have the polarizing coating of the equal above polarization property with existing product with good operability, high finished product rate, low cost, good productivity ratio manufacture.
In the past, in order to improve polymer film of polyvinyl alcohol draftability, improve homogeneity when stretching, improve and polymer film of polyvinyl alcohol is stretched and the object such as the polarization property of polarizing coating that obtains and durability, use the stoste containing vinol series polymer on one side dry masking on one side time, the adjustment etc. of the moisture content of Polyvinyl alcohol film when being filmed the adjustment of draw ratio (ratio of the transporting velocity of the Polyvinyl alcohol film between the roller of masking), masking.
As such prior art, known (1) has carried out the stretched film of molecularly oriented in order to obtain fully when uniaxial tension, adopt the masking draw ratio of less than 1, ad infinitum reduce the method (patent document 1, particularly its paragraph [0008] ~ [0009], embodiment etc.) that masking tension force carries out operating for the manufacture of the masking of polymer film of polyvinyl alcohol; (2) in order to obtain the polymer film of polyvinyl alcohol that can carry out powerful stretching, when manufacturing polymer film of polyvinyl alcohol with drum-type film-making machine, make [coiling speed of the polymer film of polyvinyl alcohol of gained]/[being positioned at the speed of the drum of the most upstream of supply masking raw material] be 0.8 ~ 1.3 method (patent document 2); (3) in order to obtain the polymer film of polyvinyl alcohol that can carry out powerful stretching, in drying process when manufacturing polymer film of polyvinyl alcohol with drum-type film-making machine, the operation speed Rc when volatile ingredient ratio of film is reached below 10 % by weight and the velocity ratio (Rf/Rc) of final coiling speed Rf are the method (patent document 3) etc. of 0.9 ~ 1.1.
In addition, known (4) are even can manufacture to obtain the polyvinyl alcohol mesentery that large area also has the polarizing coating of the wide cut of homogeneous optical property, the velocity ratio (Rf/Rc) of the speed (Rc) and coiling speed (Rf) that the volatile ingredient being positioned at polyvinyl alcohol film are reached the dryer roll of the operation of less than 10% controls 0.9 ~ 1.1, the temperature reducing drying process is unequal, thus manufactures the tensile elongation (S in MD direction m) and the tensile elongation (S in TD direction t) ratio (S m/ S t) be the method (patent document 4) of the polyvinyl alcohol mesentery of 0.7 ~ 1.3; (5) even can manufacture to obtain the polyvinyl alcohol mesentery that large area also has the polarizing coating of the wide cut of homogeneous optical property, when the volatile ingredient of polyvinyl alcohol film reaches 10 ~ 50 % by weight, from the drum being positioned at side, most upstream, polyvinyl alcohol film is peeled off, and the speed making the speed V1 of the drum being positioned at side, most upstream and the volatile ingredient being positioned at polyvinyl alcohol film just start the speed V2 of the drum of the operation being less than 10 % by weight is the method (patent document 5) of 1.0 ~ 1.3 than V2/V1.
Also known (6) can carry out homogeneous uniaxial tension to obtain providing, fine crackle and the stretched film in space is not had during stretching, comprise the polymer film of polyvinyl alcohol of specific skin/core/cortex, be the stoste heating of 50 ~ 90 quality % to the volatile ingredient ratio containing vinol series polymer with the first dryer roll, and under defined terms, hot blast is sprayed to the Polyvinyl alcohol film face do not contacted with the first dryer roll simultaneously, Polyvinyl alcohol film is peeled off from the first dryer roll by the moment reaching 15 ~ 30 quality % in volatile ingredient ratio, make it contact with the second dryer roll and carry out drying, now, make the peripheral speed (S of the first dryer roll 1) and the peripheral speed (S of the second dryer roll 2) ratio (S 2/ S 1) be 1.000 ~ 1.100 method (patent document 6) etc.
But, in above-mentioned patent document 1 ~ 6, and be not disclosed in by polymer film of polyvinyl alcohol thin for the thickness of polymer film of polyvinyl alcohol, particularly film with make during high magnification uniaxial tension film do not occur rupture scheme, particularly improve the scheme of the ultimate elongation multiplying power of film further.
Prior art document
Patent document
Patent document 1: Japanese Patent Laid-Open 6-136151 publication
Patent document 2: Japanese Patent Laid-Open 2001-315141 publication
Patent document 3: Japanese Patent Laid-Open 2001-315146 publication
Patent document 4: Japanese Patent Laid-Open 2002-30164 publication
Patent document 5: Japanese Patent Laid-Open 2002-79531 publication
Patent document 6: Japanese Patent Laid-Open 2005-324355 publication
Non-patent literature
Non-patent literature 1: " the high molecular smooth physical property of polymer science One Point 10 ", first edition the 3rd printing, altogether vertical publication Co., Ltd., on December 15th, 2007, p.19-21.
Summary of the invention
Invent problem to be solved
The object of this invention is to provide that a kind of ultimate elongation multiplying power is high, the polymer film of polyvinyl alcohol of the stretched film such as the polarizing coating of the equal above optical property with existing product that can stretch with high magnification in cases where no fracturing is occurring, thus can have with good operability, high finished product rate, low cost, good productivity ratio manufacture.
Even if object of the present invention particularly provides the polymer film of polyvinyl alcohol used in the manufacture of polarizing coating than ever thinlyyer also to have high limit stretching ratio, can carry out uniaxial tension in cases where no fracturing is occurring swimmingly when stretching with high magnification, can make stretched film thinner than ever and shorten drying time when manufacturing polarizing coating further, can manufacture the polymer film of polyvinyl alcohol of polarizing coating with better productivity ratio.
Object of the present invention is also to provide and can manufactures the method with the polymer film of polyvinyl alcohol of the characteristic of above-mentioned excellence swimmingly continuously with high production rate.
In addition, the object of this invention is to provide the polarizing coating be made up of above-mentioned polymer film of polyvinyl alcohol.
For solving the means of problem
The present inventor has carried out conscientiously studying in order to achieve the above object and repeatedly, found that, if the birefringence in the mechanical flow direction (length direction) of polymer film of polyvinyl alcohol is equalization and the birefringence of the value obtained and width equalization and the value obtained meets specific relation on the thickness direction of film on the thickness direction of film, and the birefringence of the width of polymer film of polyvinyl alcohol on the thickness direction of film equalization and the value obtained in specific number range, then the ultimate elongation multiplying power of film raises, even if stretch with high magnification the fracture of film also not easily occurs, can when not interrupting stretching operation with high finished product rate, with low cost, the stretched film such as the polarizing coating of the excellent in optical properties such as polarization property are manufactured with good productivity ratio.In addition also find, if equalization and the value obtained are in specific number range on the thickness direction of film for the birefringence in the mechanical flow direction of polymer film of polyvinyl alcohol, then the ultimate elongation multiplying power of film improves further.
Particularly find, the birefringence in the mechanical flow direction of polymer film of polyvinyl alcohol is equalization and the birefringence of the value obtained and width equalization and the value obtained meets specific relation on the thickness direction of film on the thickness direction of film, and the birefringence of width equalization and in the above-mentioned polymer film of polyvinyl alcohol of the value obtained in specific scope on the thickness direction of film, even if the thickness of the polymer film of polyvinyl alcohol that the Thickness Ratio of this film is in the past conventional in the manufacture of polarizing coating is thinner, be the thickness of about 30 ~ 65 μm, also there is high limit stretching ratio, therefore uniaxial tension can be carried out swimmingly with high magnification in cases where no fracturing is occurring, thus further filming when manufacturing polarizing coating can be realized, drying time when manufacturing polarizing coating can be shortened further.
In addition, the discoveries such as the present inventor, the above-mentioned polymer film of polyvinyl alcohol with high limit stretching ratio manufactures with high production rate swimmingly continuously by following method: the masking stoste containing vinol series polymer spued after to the first dryer roll of the film forming apparatus possessing many dryer rolls, be filmed with these many dryer rolls successively drying, now, the peripheral speed of dryer roll when making the volatile ingredient ratio of Polyvinyl alcohol film reach 13 quality % relative to the ratio of the peripheral speed of the first dryer roll in specific number range, the ratio of the peripheral speed of dryer roll when making the peripheral speed of final dryer roll reach 13 quality % relative to the volatile ingredient ratio of Polyvinyl alcohol film is in specific number range, make the peripheral speed of final dryer roll relative to the ratio of the peripheral speed of the first dryer roll in specific number range.
In addition, the discoveries such as the present inventor, when the polymer film of polyvinyl alcohol high by said method manufacturing limit stretching ratio, preferably make the volatile ingredient ratio of Polyvinyl alcohol film when peeling off from the first dryer roll in specific number range, the roll surface temperature of preferred each dryer roll is more than 65 DEG C, also have, if the volatile ingredient ratio of the masking stoste containing vinol series polymer is 60 ~ 75 quality %, and the roll surface temperature of the first dryer roll is 80 ~ 120 DEG C, even if then the peripheral speed of the first dryer roll reaches the high speed of more than 8m/ minute, the birefringence of the birefringence in mechanical flow direction that also can manufacture polymer film of polyvinyl alcohol with good productivity ratio swimmingly equalization and the value that obtains and width on the thickness direction of film equalization and the value that obtains meets specific relation on the thickness direction of film, and the birefringence of width on the thickness direction of film equalization and the value that obtains in the number range of regulation, the polymer film of polyvinyl alcohol that ultimate elongation multiplying power is high, repeatedly study further based on these discoveries, thus complete the present invention.
That is, the present invention is:
(1) polymer film of polyvinyl alcohol, is characterized in that, meets following formula (I) and (II).
Δn(MD) Ave—0.1×10 -3≤Δn(TD) Ave≤Δn(MD) Ave+0.25×10 -3(I)
Δn(TD) Ave≤2.5×10 -3(II)
[in above formula, Δ n (MD) averepresent the birefringence in mechanical flow direction of polymer film of polyvinyl alcohol equalization and value of obtaining on the thickness direction of this film, Δ n (TD) averepresent the birefringence of width of polymer film of polyvinyl alcohol equalization and value of obtaining on the thickness direction of this film].
In addition, the present invention is:
(2) polymer film of polyvinyl alcohol of above-mentioned (1), it meets following formula (III);
1.3 × 10 -3≤ Δ n (MD) ave≤ 2.0 × 10 -3(III); And
(3) polymer film of polyvinyl alcohol of above-mentioned (1) or (2), its thickness is in the scope of 30 ~ 65 μm.
The present invention is still:
(4) manufacture method of polymer film of polyvinyl alcohol, is characterized in that,
A () uses the film forming apparatus possessing the many dryer rolls that rotating shaft is parallel to each other, masking stoste containing vinol series polymer is spued to the first dryer roll of this film forming apparatus and after carrying out part drying with membranaceous, carries out drying further with follow-up dryer roll and carry out masking; Now,
Peripheral speed (the S of the dryer roll when volatile ingredient ratio of () Polyvinyl alcohol film reaches 13 quality % b t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 0.990 ~ 1.050;
Peripheral speed (the S of (c) final dryer roll l) peripheral speed (S of dryer roll when reaching 13 quality % relative to the volatile ingredient ratio of Polyvinyl alcohol film t) ratio (S l/ S t) be 0.960 ~ 0.980;
Peripheral speed (the S of (d) final dryer roll l) relative to the peripheral speed (S of the first dryer roll 1) ratio (S l/ S 1) be 0.970 ~ 1.010.
In addition, the present invention is:
(5) manufacture method of above-mentioned (4), wherein, the volatile ingredient ratio of Polyvinyl alcohol film when peeling off from the first dryer roll is 17 ~ 30 quality %;
(6) manufacture method of above-mentioned (4) or (5), wherein, the roll surface temperature of each dryer roll is more than 65 DEG C; And
(7) manufacture method any one of above-mentioned (4) ~ (6), wherein, the volatile ingredient ratio of the masking stoste containing vinol series polymer is 60 ~ 75 quality %, the roll surface temperature of the first dryer roll is 80 ~ 120 DEG C, the peripheral speed (S of the first dryer roll 1) be 8 ~ 25m/ minute.
In addition, the present invention is:
(8) polarizing coating, its polymer film of polyvinyl alcohol any one of above-mentioned (1) ~ (3) is made.
The effect of invention
Polymer film of polyvinyl alcohol of the present invention has high limit stretching ratio, therefore when manufacturing stretched film, even if also not easily there is the fracture of film with high magnification uniaxial tension, thus can when not interrupting stretching operation with high finished product rate, with low cost, the stretched film such as polarizing coating manufacturing the excellent in optical properties such as polarization property with good productivity ratio.
Even if particularly the Thickness Ratio of polymer film of polyvinyl alcohol film of the present invention in the past in order to the thickness manufacturing polarizing coating etc. and conventional polymer film of polyvinyl alcohol is thinner, be the thickness of about 30 ~ 65 μm, also there is high limit stretching ratio, therefore uniaxial tension can be carried out swimmingly with high magnification in cases where no fracturing is occurring, thus further filming when manufacturing stretched film can be realized, drying time when manufacturing polarizing coating etc. can be shortened further, and can boost productivity by this.
In addition, in recent years, as the former film of polarizing coating, also use length more than the polymer film of polyvinyl alcohol of 1000m, and polymer film of polyvinyl alcohol of the present invention has high limit stretching ratio, therefore can stretch with multiplying power higher than ever, the amount of obtaining of the polarizing coating be thus made up of polymer film of polyvinyl alcohol is more than ever before.
By adopting manufacture method of the present invention, the polymer film of polyvinyl alcohol of the present invention with the characteristic of above-mentioned excellence can be manufactured swimmingly continuously with high production rate.
Accompanying drawing explanation
[Fig. 1] Fig. 1 represents the Δ n (MD) measuring polymer film of polyvinyl alcohol avetime the schematic diagram of acquisition method of sample.
[Fig. 2] Fig. 2 represents the Δ n (TD) measuring polymer film of polyvinyl alcohol avetime the schematic diagram of acquisition method of sample.
Detailed description of the invention
Below, the present invention is described in detail.
In general, in the transparent film made with transparent polymer such as vinol series polymers, polymer chain under the effect of the plastic deformation caused by shear stress and strain etc. along flow direction (mechanical flow direction: length direction) orientation, the polarised direction forming the atomic group of polymer is consistent on microcosmic, thus produces the distinctive birefringence of polymer (non-patent literature 1).
The birefringence [Δ n (MD)] in the mechanical flow direction of polymer film of polyvinyl alcohol is tried to achieve by following formula [i], and in addition, the birefringence [Δ n (TD)] of width is tried to achieve by following formula [ii].
Δn(MD)=nMD-nz [i]
Δn(TD)=nTD-nz [ii]
[in formula, nMD represents the refractive index in the mechanical flow direction (length direction) of film, and nTD represents the refractive index of the width of film, and nz represents the refractive index of the thickness direction of film].
As recorded in non-patent literature 1, in the film made with transparent polymer such as vinol series polymers, form the polymer chain of film easily along mechanical flow direction (length direction) orientation, comprise in the polymer film of polyvinyl alcohol of the polymer film of polyvinyl alcohol recorded in above-mentioned patent document 1 ~ 6, the general relation in " birefringence [Δ n (MD)] in mechanical flow direction " > " birefringence [Δ n (TD)] of width ", namely, the birefringence [Δ n (MD)] in mechanical flow direction is easily larger than the birefringence [Δ n (TD)] of width.
In contrast, polymer film of polyvinyl alcohol of the present invention meets following formula (I) and (II), different from existing polymer film of polyvinyl alcohol in this.
Δn(MD) Ave—0.1×10 -3≤Δn(TD) Ave≤Δn(MD) Ave+0.25×10 -3(I)
Δn(TD) Ave≤2.5×10 -3(II)
[in above formula, Δ n (MD) averepresent the birefringence in mechanical flow direction of polymer film of polyvinyl alcohol equalization and value of obtaining on the thickness direction of this film, Δ n (TD) averepresent the birefringence of width of polymer film of polyvinyl alcohol equalization and value of obtaining on the thickness direction of this film].
Namely, from above formula (I), in polymer film of polyvinyl alcohol of the present invention (sometimes " polyvinyl alcohol " being called " PVA " below), the birefringence of the mechanical flow direction of PVA series polymer film (manufacturing streamline direction during PVA series polymer film continuously) [hereinafter sometimes referred to " length direction (MD) "] equalization and value " the Δ n (MD) that obtains on the thickness direction of this film ave" with the birefringence of the width (direction at a right angle with length direction) [hereinafter sometimes referred to " width (TD) "] of PVA series polymer film equalization and value " the Δ n (TD) that obtains on the thickness direction of this film ave" equal or smaller, even if or exceed " Δ n (TD) ave", its amount is also little.
PVA series polymer film of the present invention, except this formula (I), also has the feature meeting above formula (II).
PVA series polymer film of the present invention meets above formula (I) and (II), even if thus when the Thickness Ratio of film is in the past thin, also there is high limit stretching ratio, even if thus also not easily there is the fracture of film with high magnification uniaxial tension when manufacturing the stretched film such as polarizing coating, the interruption of stretching operation can not be caused because of the fracture of film, can with high finished product rate, the stretched film manufacturing the filming of the excellent in optical properties such as polarization property with good productivity ratio.
If do not meet above formula (I), then the ultimate elongation multiplying power of PVA series polymer film reduces, and easily there is the fracture of film during high magnification uniaxial tension, particularly easily ruptures when the thickness of film is thin.
PVA series polymer film of the present invention preferably meets following formula (I '), more preferably meets following formula (I ' '), preferably meets following formula (I ' ' ') further.
Δn(MD) Ave-0.05×10 -3≤Δn(TD) Ave≤Δn(MD) Ave+0.23×10 -3(I’)
Δn(MD) Ave≤Δn(TD) Ave≤Δn(MD) Ave+0.2×10 -3(I’’)
Δn(MD) Ave+0.05×10 -3≤Δn(TD) Ave≤Δn(MD) Ave+0.18×10 -3(I’’’)
In addition, if the Δ n (TD) of PVA series polymer film avebe greater than 2.5 × 10 -3, outside the scope of above-mentioned formula (II), then the ultimate elongation multiplying power of PVA series polymer film reduces, and is difficult to PVA series polymer film is stretched with high magnification at length direction (MD), is difficult to the stretched film obtaining excellent in optical properties.
In order to exceedingly reduce Δ n (TD) ave, needing the drying allowing width when manufacturing PVA series polymer film to shrink, having the tendency that the effective width yield of PVA series polymer film reduces, therefore the Δ n (TD) of PVA series polymer film of the present invention avepreferably 1.5 × 10 -3~ 2.2 × 10 -3scope in, more preferably 1.6 × 10 -3~ 2.0 × 10 -3scope in.
PVA series polymer film of the present invention, except above formula (I) and (II), preferably also meets following formula (III).
1.3×10 -3≤Δn(MD) Ave≤2.0×10 -3(III)
By the Δ n (MD) of PVA series polymer film ave2.0 × 10 -3below, the ultimate elongation multiplying power of PVA series polymer film improves further, is easily stretched with high magnification at length direction (MD) by PVA series polymer film, more easily obtains the stretched film of excellent in optical properties.On the other hand, in order to make the Δ n (MD) of PVA series polymer film avebe less than 1.3 × 10 -3, need the peripheral speed ratio greatly reducing dryer roll, therefore have the tendency that PVA based polymer film easily relaxes between dryer roll when masking.
The Δ n (MD) of PVA series polymer film of the present invention avemore preferably 1.4 × 10 -3~ 1.95 × 10 -3scope in, preferred 1.5 × 10 further -3~ 1.9 × 10 -3scope in.
In addition, in PVA series polymer film, at the upper Δ n (MD) of the width (TD) of film aveand/or Δ n (TD) avevalue often can change, particularly at the both ends of width, Δ n (MD) aveeasy rising, as long as but at least meet formula (I) and (II) at the central portion of the width (TD) of PVA series polymer film, preferably meet formula (I) ~ (III), in the whole region of 8 one-tenth of the width (TD) centered by the central part of the width of PVA series polymer film (TD) above parts, preferably meet formula (I) and (II), preferably meet formula (I) ~ (III).Removing (deburring) can be cut in the both ends not meeting the width (TD) of the PVA series polymer film of formula (I) and (II) before by PVA series polymer film alongst (MD) stretching.
" the Δ n (MD) of PVA series polymer film ave" [birefringence of the length direction (MD) of PVA series polymer film on the thickness direction of this film equalization and the value obtained] and " Δ n (TD) ave" [birefringence of the width (TD) of PVA series polymer film on the thickness direction of this film equalization and the value obtained] measure by following methods.
" 1 " Δ n (MD) avedetermination method:
(that exemplify here is the Δ n (MD) of the central portion of the width (TD) of PVA series polymer film avedetermination method.)
I () is on the optional position of the length direction (MD) of PVA series polymer film, cut out the shred of the size of MD × TD=2mm × 10mm from the central portion of the width (TD) of film as Suo Shi Fig. 1 (a), the PET film of this shred with thick 100 μm is clamped from both sides, be clipped in again in wooden frame, be installed on slicer device.
(ii) then, by the shred that gathers as mentioned above, as Suo Shi Fig. 1 (b), the length direction (MD) of (PET film and wooden frame not shown) and shred, abreast with the cut-space of 10 μm, manufactures the section (MD × TD=2mm × 10 μm) of the observation shown in 10 Fig. 1 (c).From this section, select 5 tangent planes level and smooth and there is no the section of slice thickness inequality, by their respectively placing on slide, measure slice thickness with microscope (Keyemce Inc.).In addition, observe in the visual field of 10 times, eyepiece, 20 times, object lens (amounting to 200 times).
(iii) then, in order to can tangent plane be observed, to cut into slices and to fall as described in Fig. 1 (d), make cut side up placing on slide, with cover glass and silicone oil (refractive index 1.04) sealing, measure the delay of 5 sections with two-dimentional photoelastic evaluation system " PA-micro " (P Co., Ltd. hotonic Lattice system).
(iv) under the state that the delay of each section distribution is presented on the mensuration picture of " PA-micro ", the vertical line α in the surface original with film is marked in the mode of cross sectional, in the enterprising line linearity analysis of this line segment α, obtain the delay distributed data of the thickness direction of film.In addition, observe in the visual field of 10 times, eyepiece, 20 times, object lens (amounting to 200 times).In addition, in order to the error suppressing the change of position because the line segment α in section passes through to cause, live width is set to 300 pixels, gets the mean value of delay.
V value that the delay of the thickness direction of the film obtained as mentioned above distributes by () is divided by the thickness recorded with microscope, obtain birefringence Δ n (MD) distribution of the thickness direction of film, the mean value that the birefringence Δ n (MD) getting the thickness direction of this film distributes.The mean value distributed by the birefringence Δ n (MD) of the thickness direction for 5 films of trying to achieve respectively of cutting into slices is average further, as " Δ n (MD) ave".
" 2 " Δ n (TD) avedetermination method:
(that exemplify here is the Δ n (TD) of the central portion of the width (TD) of PVA series polymer film avedetermination method.)
I () is on the optional position of the length direction (MD) of PVA series polymer film, cut out the shred of the size of MD × TD=10mm × 2mm from the central portion of the width (TD) of film as Suo Shi Fig. 2 (a), the PET film of this shred with thick 100 μm is clamped from both sides, be clipped in again in wooden frame, be installed on slicer device.
(ii) then, by the shred that gathers as mentioned above, as Suo Shi Fig. 2 (b), the width (TD) of (PET film and wooden frame not shown) and shred, abreast with the cut-space of 10 μm, manufactures the section (MD × TD=10 μm × 2mm) of the observation shown in 10 Fig. 2 (c).From this section, select 5 tangent planes level and smooth and there is no the section of slice thickness inequality, by their respectively placing on slide, measure slice thickness with microscope (Keyemce Inc.).In addition, observe in the visual field of 10 times, eyepiece, 20 times, object lens (amounting to 200 times).
(iii) then, in order to can tangent plane be observed, to cut into slices and to fall as described in Fig. 2 (d), make cut side up placing on slide, with cover glass and silicone oil (refractive index 1.04) sealing, measure the delay of 5 sections with two-dimentional photoelastic evaluation system " PA-micro " (P Co., Ltd. hotonic Lattice system).
(iv) under the state that the delay of each section distribution is presented on the mensuration picture of " PA-micro ", the vertical line β in the surface original with film is marked in the mode of cross sectional, in the enterprising line linearity analysis of this line segment β, obtain the delay distributed data of the thickness direction of film.In addition, observe in the visual field of 10 times, eyepiece, 20 times, object lens (amounting to 200 times).In addition, in order to the error suppressing the change of position because the line segment β in section passes through to cause, live width is set to 300 pixels, gets the mean value of delay.
V value that the delay of the thickness direction of the film obtained as mentioned above distributes by () is divided by the thickness recorded with microscope, obtain birefringence Δ n (TD) distribution of the thickness direction of film, the mean value that the birefringence Δ n (TD) getting the thickness direction of this film distributes.The mean value distributed by the birefringence Δ n (TD) of the thickness direction for 5 films of trying to achieve respectively of cutting into slices is average further, as " Δ n (TD) ave".
The thickness of PVA series polymer film of the present invention can in the scope of 5 ~ 150 μm, as in the former film situation etc. of polarizing coating, is preferably 30 ~ 65 μm.PVA series polymer film of the present invention has high limit stretching ratio, even if therefore Film Thickness Ratio in the past the multiplex thickness making the former film of polarizing coating be that the PVA series polymer film of about 75 μm is thinner, when being 30 ~ 65 μm as mentioned above, also can stretch with high magnification when there is not the fracture of film, thus can have the stretched film of the optical characteristics such as the polarization property above on an equal basis with existing product swimmingly with good productivity ratio manufacture with high finished product rate, and stretched with high magnification by the PVA series polymer film by thickness being 30 ~ 65 μm, the Thickness Ratio of the film after stretching can be made in the past thinner, and the drying time that can shorten when manufacturing polarizing coating, the manufacturing speed of polarizing coating can be improved.
If the thickness of PVA series polymer film is blocked up, is then difficult to promptly carry out drying when manufacturing polarizing coating, on the other hand, if the thickness of PVA series polymer film is excessively thin, then the fracture of film easily occurs when the uniaxial tension for the manufacture of polarizing coating.
The width of PVA series polymer film of the present invention is not particularly limited, but in recent years, because the large screen of LCD TV, display screen, so in order to can effectively use wherein, width is preferably more than 2m, is more preferably more than 3m, more preferably more than 4m.In addition, when in fact manufacturing polarizer by production machine, if the width of film is excessive, be then difficult to carry out homogeneous uniaxial tension, therefore the width of PVA series polymer film is preferably below 8m.
Its quality swellbility of PVA series polymer film of the present invention is preferably 180 ~ 250%, is more preferably 185 ~ 240%, and more preferably 190 ~ 230%.If the quality swellbility of PVA series polymer film is too low, is then difficult to stretch, has the tendency being difficult to the stretched film manufacturing excellent in optical properties, on the other hand, if quality swellbility is too high, then operation when stretching is deteriorated by property, sometimes cannot obtain the polarizing coating of high-durability.
Quality swellbility mentioned here refers to the percentage of the value that quality when PVA series polymer film being flooded in the distilled water of 30 DEG C 30 minutes obtains divided by the quality after above-mentioned dipping at 105 DEG C after dry 16 hours, and the method specifically by recording in following examples measures.
As forming the PVA based polymer of PVA series polymer film of the present invention, the polyvinylesters saponification that such as obtains making vinyl esters be polymerized and the PVA obtained, the modified PVA based polymer that comonomer graft copolymerization is obtained on the main chain of PVA can be exemplified, vinyl esters and comonomer will be made and the modified polyvinyl ester saponification that obtains and make modified PVA based polymer, a part for the hydroxyl of unmodified PVA or modified PVA based polymer is cross-linked by aldehydes such as formaldehyde, butyraldehyde, benzaldehydes and the so-called polyvinyl acetal resin etc. that obtains.
When the PVA based polymer forming PVA series polymer film of the present invention is modified PVA based polymer, the modification amount of PVA based polymer is preferably less than 15 % by mole, is more preferably less than 5 % by mole.
The above-mentioned vinyl esters used in manufacture as PVA based polymer, can exemplify such as vinyl acetate, vinyl formate, vinyl laurate, propionate, vinyl butyrate, new vinyl acetate acid, tertiary ethylene carbonate, stearic acid vinyl ester, vinyl benzoate etc.These vinyl esters can be used alone or in combination.In these vinyl esters, from the preferred vinyl acetate of the viewpoint of productivity ratio.
In addition, as above-mentioned copolymer, the olefines (alpha-olefin etc.) of the carbon numbers 2 ~ 30 such as such as ethene, propylene, 1-butylene, isobutene can be exemplified; Acrylic acid or its salt; The esters of acrylic acids (such as acrylic acid carbon number 1 ~ 18 Arrcostab) such as methyl acrylate, ethyl acrylate, n-propyl, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, acrylic acid-2-ethyl caproite, dodecylacrylate, octadecyl acrylate; Methacrylic acid or its salt; The methyl acrylic esters (carbon number 1 ~ 18 Arrcostab of such as methacrylic acid) such as methyl methacrylate, EMA, n propyl methacrylate, isopropyl methacrylate, n-BMA, isobutyl methacrylate, Tert-butyl Methacrylate, methacrylic acid-2-Octyl Nitrite, lauryl methacrylate, octadecyl methacrylate; Acrylamide, N methacrylamide, N-ethyl acrylamide, N,N-DMAA, DAAM, acryamidopropanesulfonic acid or its salt, acrylamido diemethylamine or the acrylamide derivative such as its salt, N hydroxymethyl acrylamide or derivatives thereof; Methacrylamide, N-methyl methacrylamide, N-ethyl methacrylamide, methacryl amido propane sulfonic acid or its salt, methacryiamidopropyl dimethylamine or the methacrylamide derivatives such as its salt, N-methylol methacrylamide or derivatives thereof; The N-vinylamide classes such as N-vinyl formamide, N-vinyl acetamide, NVP; The vinyl ethers such as methyl vinyl ether, ethyl vinyl ether, n-propyl vinyl ether, isopropyl-ethylene base ether, n-butyl vinyl ether, IVE, tert-Butyl vinyl ether, dodecyl vinyl, stearyl vinyl ethers; The nitrile such as acrylonitrile, methacrylonitrile; The vinyl halides base class such as vinyl chloride, vinylidene chloride, PVF, vinylidene; The allyl compound such as allyl acetate, chloropropene; The derivatives such as the unsaturated dicarboxylic such as maleic acid, itaconic acid, its salt or its ester; The vinyl silanes based compounds such as vinyltrimethoxy silane; Methylvinyl acetate; Unsaturated sulfonic acid or derivatives thereof etc.Wherein preferred alpha-olefin, particularly preferably ethene.
From the viewpoint of the polarization property and durability etc. of the polarizing coating of gained, the average degree of polymerization forming the PVA based polymer of PVA series polymer film of the present invention is preferably more than 1000, is more preferably more than 1500, and more preferably more than 2000.On the other hand, from the viewpoint of the easiness, draftability etc. of the manufacture of the PVA series polymer film of homogeneous, the upper limit of the average degree of polymerization of PVA based polymer is preferably less than 8000, is particularly preferably less than 6000.
Here, " average degree of polymerization " of the PVA based polymer in this description refers to the average degree of polymerization recorded for benchmark with JIS K6726-1994, tries to achieve according to by the inherent viscosity recorded in the water of 30 DEG C after the saponification again of PVA based polymer, purifying.
From the viewpoint of the polarization property and durability etc. of the polarizing coating of gained, the saponification degree forming the PVA based polymer of PVA series polymer film of the present invention is preferably more than 95.0 % by mole, be more preferably more than 98.0 % by mole, more preferably more than 99.0 % by mole, most preferably be more than 99.3 % by mole.
Here, " saponification degree " of the PVA based polymer in this description refers to relative to the ratio (% by mole) shared by the molal quantity of the total mole number of the construction unit changing into vinyl alcohol units by saponification (typically vinyl ester units) and vinyl alcohol units, this vinyl alcohol units.The saponification degree of PVA based polymer measures with the benchmark that is recited as of JIS K6726-1994.
The method for making of PVA series polymer film of the present invention is not particularly limited, as long as the method for the PVA series polymer film meeting above formula (I) and (II) can be manufactured, namely manufacture by any one method, and PVA series polymer film of the present invention can be manufactured with high production rate swimmingly continuously by manufacture method of the present invention, this manufacture method comprises the steps:
A () uses the film forming apparatus possessing the many dryer rolls that rotating shaft is parallel to each other, masking stoste containing PVA based polymer is spued to the first dryer roll of this film forming apparatus and after carrying out part drying with membranaceous, carries out drying further with follow-up dryer roll and carry out masking; Now,
Peripheral speed (the S of the dryer roll when volatile ingredient ratio of () PVA based polymer film reaches 13 quality % b t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 0.990 ~ 1.050;
Peripheral speed (the S of (c) final dryer roll l) peripheral speed (S of dryer roll when reaching 13 quality % relative to the volatile ingredient ratio of PVA based polymer film t) ratio (S l/ S t) be 0.960 ~ 0.980;
Peripheral speed (the S of (d) final dryer roll l) relative to the peripheral speed (S of the first dryer roll 1) ratio (S l/ S 1) be 0.970 ~ 1.010.
Below more specific description is carried out to the manufacture method of the PVA series polymer film of the invention described above.
Masking stoste containing PVA based polymer makes solution or by the meltings such as the PVA based polymer particle containing liquid medium etc. are made fused solution to prepare by being mixed with liquid medium by PVA based polymer.
The melting of the dissolving of PVA based polymer in liquid medium, PVA based polymer particle containing liquid medium etc. can be carried out with stirring-type mixing arrangement, melt extruder etc.
As liquid medium now used, can exemplify such as water, methyl-sulfoxide, dimethyl formamide, dimethylacetylamide, 1-METHYLPYRROLIDONE, ethylenediamine, diethylenetriamines etc., these liquid mediums one can be used alone or be used in combination.Wherein preferably use water, methyl-sulfoxide or both mixtures, particularly preferably use water.
From operation when promoting that the dissolving of PVA based polymer liquid medium, melting, raising film manufacture by property, the viewpoint improving the draftability etc. of the PVA series polymer film of gained, preferably in masking stoste, add plasticizer.
As plasticizer, preferably use polyalcohol, can exemplify such as ethylene glycol, glycerine, diglycerol, propane diols, diethylene glycol, triethylene glycol, TEG, trimethylolpropane etc., these plasticizer one can be used alone or be used in combination.From the viewpoint of the raising excellent effect of draftability, wherein preferably use in glycerine, diglycerol and ethylene glycol one or more.
The addition of plasticizer is preferably 0 ~ 30 mass parts relative to PVA based polymer 100 mass parts, is more preferably 3 ~ 25 mass parts, is particularly preferably 5 ~ 20 mass parts.If the addition of plasticizer is relative to PVA based polymer 100 mass parts more than 30 mass parts, then the PVA series polymer film of gained is too soft sometimes, and treatability reduces.
From raising from the viewpoint of the treatability of the PVA series polymer film of the fissility dryer roll when manufacturing PVA series polymer film, gained etc., preferably in masking stoste, add surfactant.As the kind of surfactant, be not particularly limited, preferably use anionic surfactant or nonionic surfactant.
As anionic surfactant, preference is as the anionic surfactant of the sulfonic acid types such as sulfuric acid ester type, dodecyl benzene sulfonate such as the carboxylic acid types such as potassium laurate, sulfuric acid monooctyl ester.
In addition, as nonionic surfactant, preference is as the nonionic surfactant of the allyl phenyl ether type such as the alkylol amide type such as polypropylene glycol ether type, oleic acid diethyl amide, polyoxyalkylene allyl phenyl ether such as alkyl amine type, the polyoxyethylene laural acid amides etc. such as the alkyl ester such as the alkyl phenyl such as alkyl ether type, NONIN HS 240 ether type, polyoxyethylene laurate, polyoxyethylene laural base amino ethers alkylamide type, polyoxyethylene poly-oxygen propylene aether such as polyoxyethylene oleyl ether.These surfactants one can be used alone or be used in combination.
The addition of surfactant is preferably 0.01 ~ 1 mass parts relative to PVA based polymer 100 mass parts, is more preferably 0.02 ~ 0.5 mass parts, is particularly preferably 0.05 ~ 0.3 mass parts.If be less than 0.01 mass parts, be then sometimes difficult to the raising effect embodying masking, fissility, on the other hand, if more than 1 mass parts, then surfactant, in film surface stripping, becomes the reason of adhesion sometimes, and treatability reduces.
Masking stoste can contain various additive in the scope of characteristic not hindering PVA series polymer film of the present invention, such as stabilizing agent (such as antioxidant, ultra-violet absorber, heat stabilizer etc.), bulking agent (dissolving drug mutually), anti-blocking agent, fire retardant, antistatic agent, lubricant, dispersant, fluidizing reagent, antiseptic etc.These additives one can be used alone or be used in combination.
The volatile ingredient ratio of the masking stoste used in the manufacture of PVA series polymer film is preferably 60 ~ 75 quality %, is more preferably 65 ~ 70 quality %.If the volatile ingredient ratio of masking stoste is less than 60 quality %, then the viscosity of masking stoste raises, and be difficult to carry out filtering and deaeration, in addition masking itself is all very difficult sometimes.On the other hand, if the volatile ingredient ratio of masking stoste is greater than 75 quality %, then viscosity is too low sometimes, and the homogeneity of the thickness of PVA series polymer film is impaired.
Here, said in this description " the volatile ingredient ratio of masking stoste " refers to the volatile ingredient ratio of being tried to achieve by following formula [iii].
Volatile ingredient ratio (quality %)={ (Wa-Wb)/Wa} × 100 [iii] of masking stoste
[in formula, Wa represents the quality (g) of masking stoste, and Wb represents the quality (g) of the masking stoste of Wa (g) in the electric air drier of 105 DEG C after dry 16 hours.]
What use in the manufacture of PVA series polymer film possesses in the film forming apparatus of the many dryer rolls that rotating shaft is parallel to each other, and the quantity of dryer roll is preferably more than 3, is more preferably more than 4, more preferably 5 ~ 30.
Many dryer rolls are such as preferred to be formed by metals such as nickel, chromium, copper, iron, stainless steels, and particularly preferably by roller surface, not easily burn into and the metal material with bright luster are formed.In addition, in order to improve the durability of dryer roll, plating is more preferably used to have the dryer roll of the nickel dam, layers of chrome, nickel/chromium alloy layer etc. of individual layer or two-layer above combination.
The roll surface temperature of each dryer roll in many dryer rolls is preferably more than 65 DEG C, is more preferably more than 75 DEG C.In addition, as the roll surface temperature of each dryer roll, the roll surface temperature of the dryer roll that can use as Heat treating roll in final operation or operation close is with it preferably more than 100 DEG C, and be more preferably 100 ~ 120 DEG C, the roll surface temperature of dryer roll is in addition preferably less than 100 DEG C.
The film forming apparatus used in the present invention can have the hot-air drying device, annealing device, humidity control device etc. of hot-blast stove formula as required after many dryer rolls.
During by the masking stoste containing PVA based polymer with membranaceous spuing to the first dryer roll of film forming apparatus, such as use the membranaceous device for discharging fixed (membranaceous casting device) that T-shaped slit die, hopper plate (hopper plate), I-mould, lip coater mould etc. are known, by the masking stoste containing PVA based polymer with membranaceous spue (curtain coating) on the first dryer roll.
On the first dryer roll with membranaceous spue dry on the first dryer roll containing the liquid of PVA based polymer, peel off from the first dryer roll in the moment that the volatile ingredient ratio of PVA based polymer film reaches preferably 17 ~ 30 quality %, be more preferably 17 ~ 29 quality %, more preferably 18 ~ 28 quality %.
If the volatile ingredient ratio of PVA based polymer film when peeling off from the first dryer roll is less than 17 quality %, then there is Δ n (MD) avevalue relative to Δ n (TD) aveincrease and do not meet the tendency of formula (I), on the other hand, if the volatile ingredient ratio of PVA based polymer film when peeling off from the first dryer roll is more than 30 quality %, then has and be difficult to peel off from the first dryer roll, fracture occurs sometimes or easily produces uneven tendency.
Here, " the volatile ingredient ratio of PVA based polymer film or PVA series polymer film " in this description refers to the volatile ingredient ratio of being tried to achieve by following formula [iv].
A (quality %)={ (Wc-Wd)/Wc} × 100 [iv]
[in formula, A represents the volatile ingredient ratio (quality %) of PVA based polymer film or PVA series polymer film, Wc represents the quality (g) of the sample gathered from PVA based polymer film or PVA series polymer film, and Wd represents the dry 4 little quality (g) constantly of vacuum drier above-mentioned sample Wc (g) being put into temperature 50 C, below pressure 0.1kPa].
By using PVA based polymer, the polyalcohols such as glycerine (plasticizer), in the PVA based polymer film that the masking stoste prepared of surfactant and water is formed or PVA series polymer film, at above-mentioned " temperature 50 C, below pressure 0.1kPa, 4 hours " condition under dry time, water is mainly only had to volatilize, other composition beyond water volatilizees hardly, remain in PVA based polymer film or PVA series polymer film, therefore the volatile ingredient ratio of PVA based polymer film or PVA series polymer film is tried to achieve by measuring amount of moisture (moisture content) contained in PVA based polymer film or PVA series polymer film.
Time dry with the first dryer roll, from the viewpoint of homogeneous drying property, rate of drying etc., the roll surface temperature of the first dryer roll is preferably 80 ~ 120 DEG C, is more preferably 85 ~ 105 DEG C, more preferably 93 ~ 99 DEG C.If the surface temperature of the first dryer roll is higher than 120 DEG C, then film easily foams, and on the other hand, during lower than 80 DEG C, the drying on the first dryer roll is insufficient, becomes and peels off bad reason.
From the viewpoint of the productivity ratio of homogeneous drying property, rate of drying and PVA series polymer film etc., the peripheral speed (S of the first dryer roll 1) be preferably 8 ~ 25m/ minute, be more preferably 11 ~ 23m/ minute, more preferably 14 ~ 22m/ minute.If the peripheral speed (S of the first dryer roll 1) being less than 8m/ minute, then productivity ratio reduces, and birefringence easily increases, not preferably.On the other hand, if the peripheral speed (S of the first dryer roll 1) being greater than 25m/ minute, then the drying on the first dryer roll is easily insufficient, not preferably.
The heat from the first dryer roll can be only utilized to carry out with the part drying of the membranaceous masking stoste containing PVA based polymer spued on the first dryer roll, but from the viewpoint of homogeneous drying property, rate of drying etc., preferably while carrying out heating with the first dryer roll, hot blast is sprayed to the face do not contacted with the first dryer roll (hereinafter sometimes referred to " the first dryer roll noncontact face "), apply heat from the two sides of PVA based polymer film and carry out drying.
When hot blast is sprayed to the first dryer roll noncontact face of the PVA based polymer film be positioned on the first dryer roll, preferably to the hot blast of whole area spray wind speed 1 ~ 10m/ second in the first dryer roll noncontact face, more preferably spray the hot blast of wind speed 2 ~ 8m/ second, preferably spray the hot blast of wind speed 3 ~ 8m/ second further.
If too small to the wind speed of the hot blast that the first dryer roll noncontact face is sprayed, then be difficult to obtain as the high PVA series polymer film of the ultimate elongation multiplying power of target of the present invention, and time dry on the first dryer roll, there is the condensation of steam etc., this water droplet drops onto on PVA based polymer film, easily produces defect in the PVA series polymer film finally obtained.On the other hand, if excessive to the wind speed of the hot blast that the first dryer roll noncontact face is sprayed, then be difficult to obtain as the high PVA series polymer film of the ultimate elongation multiplying power of target of the present invention, and the PVA series polymer film finally obtained produces uneven thickness, easily there is the problems such as the uneven generation of dyeing thereupon.
From the viewpoint of drying efficiency, dry homogeneity etc., 50 ~ 150 DEG C are preferably to the temperature of the hot blast that the first dryer roll noncontact face of PVA based polymer film is sprayed, are more preferably 70 ~ 120 DEG C, more preferably 80 ~ 95 DEG C.In addition, 10 ~ 15 DEG C are preferably to the dew-point temperature of the hot blast that the first dryer roll noncontact face of PVA based polymer film is sprayed.If too low to the temperature of the hot blast that the first dryer roll noncontact face of PVA based polymer film is sprayed, then drying efficiency, homogeneous drying property etc. easily reduce, and on the other hand, if too high, then easily foam.
Mode for spraying hot blast to the first dryer roll noncontact face of PVA based polymer film is not particularly limited, can adopt and can spray homogeneous and any one mode of the hot blast that temperature is homogeneous of wind speed equably to the first dryer roll noncontact face of PVA based polymer film, preferably its entirety, wherein preferably adopt nozzle mode, cowling panel mode or their combination etc.The injection direction of the hot blast on the first dryer roll noncontact face of PVA based polymer film both can be the direction relative with the first dryer roll noncontact face, also can be roughly along the direction (roughly along the direction of the circumference on the roller surface of the first dryer roll) of the circumferential shapes in the first dryer roll noncontact face of PVA based polymer film, or also can be direction in addition.
In addition, during the PVA based polymer film on the first dryer roll dry, be preferably exhausted by the dry volatile ingredient that produced by PVA based polymer film and the hot blast after spraying.The method of exhaust is not particularly limited, and preferably adopts the method for exhausting that wind speed is uneven and temperature is uneven that can not produce the hot blast that the first dryer roll noncontact face of PVA based polymer film is sprayed.
The PVA based polymer film first dryer roll is preferably dried to volatile ingredient ratio reaches 17 ~ 30 quality % is peeled off from the first dryer roll, this time, preferably make the first dryer roll noncontact face of PVA based polymer film relative with the second dryer roll, carry out drying with the second dryer roll
Peripheral speed (the S of the second dryer roll 2) relative to the peripheral speed (S of the first dryer roll 1) ratio (S 2/ S 1) be preferably 1.005 ~ 1.090, be more preferably 1.010 ~ 1.080.If ratio (S 2/ S 1) being less than 1.005, then PVA based polymer film easily becomes heterogeneity from the pick-up point the first dryer roll, and the birefringence inequality of width increases, and sometimes cannot be used as the former film of optical film.In addition, if ratio (S 2/ S 1) be greater than 1.090, be then difficult to the PVA series polymer film of the present invention obtaining having high limit stretching ratio.
Time dry with the second dryer roll, from the viewpoint of homogeneous drying property, rate of drying etc., the roll surface temperature of the second dryer roll is preferably 65 ~ 100 DEG C, is more preferably 65 ~ 98 DEG C, more preferably 75 ~ 96 DEG C.
To peel off from the second dryer roll with the second dryer roll dried PVA based polymer film, according to the quantity etc. of the dryer roll arranged in film forming apparatus, with the 3rd dryer roll, the 4th dryer roll, the 5th dryer roll ... drying is carried out successively etc. many dryer rolls.
Now, in the present invention, the tension force putting on PVA based polymer film is regulated to carry out drying, the peripheral speed (S of dryer roll when reaching 13 quality % to make the volatile ingredient ratio of PVA based polymer film t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 0.990 ~ 1.050.Here, as " the volatile ingredient ratio of PVA based polymer film reaches dryer roll during 13 quality % ", the volatile ingredient ratio of PVA based polymer film reaches 13 quality % on dryer roll, refer to this dryer roll, volatile ingredient ratio reaches 13 quality % between two dryer rolls, refer to position dryer roll rearward in these two dryer rolls.By making ratio (S t/ S 1) in above-mentioned scope, the problems such as lax, the circumvolution of film can not be there is in the drying process that the volatile ingredient ratio of PVA based polymer film reaches till 13 quality %, can the birefringence of factory length direction (MD) swimmingly equalization and value [the Δ n (MD) that obtains on the thickness direction of film ave] and the birefringence of width (TD) equalization and value [the Δ n (TD) obtained on the thickness direction of film ave] meet above formula (I) and (II) and then also meet the PVA series polymer film of the present invention of above formula (III).
Manufacture above-mentioned ratio (S during PVA series polymer film t/ S 1) be preferably 1.000 ~ 1.045.
In the present invention, PVA based polymer film volatile ingredient ratio being reached 13 quality % is dry further with follow-up dryer roll, makes PVA based polymer film.Now, in the present invention, make the peripheral speed (S of final dryer roll l) peripheral speed (S of dryer roll when reaching 13 quality % relative to the volatile ingredient ratio of PVA series polymer film t) ratio (S l/ S t) in the scope of 0.960 ~ 0.980, carry out drying.By making ratio (S l/ S t) in above-mentioned scope, obtaining can not occurring in the drying process till final PVA series polymer film the problem such as lax, circumvolution of film, can the birefringence of factory length direction (MD) swimmingly equalization and value [the Δ n (MD) that obtains on the thickness direction of film ave] and the birefringence of width (TD) equalization and value [the Δ n (TD) obtained on the thickness direction of film ave] meet above formula (I) and (II) and then also meet the PVA series polymer film of the present invention of above formula (III).
Manufacture above-mentioned ratio (S during PVA series polymer film l/ S t) be preferably 0.963 ~ 0.976.
In addition, when manufacturing PVA series polymer film by said method, the birefringence of the length direction (MD) of PVA series polymer film equalization and value [the Δ n (MD) obtained on the thickness direction of film ave] and the birefringence of width (TD) equalization and value [the Δ n (TD) obtained on the thickness direction of film ave] according to the peripheral speed (S of the first dryer roll 1) and the peripheral speed (S of final dryer roll l) ratio (S l/ S 1) and change.In order to manufacture the PVA series polymer film of the present invention meeting above formula (I) and (II) and then also meet above formula (III) swimmingly, need the peripheral speed (S making final dryer roll l) relative to the peripheral speed (S of the first dryer roll 1) ratio (S l/ S 1) in the scope of 0.970 ~ 1.010, preferably in the scope of 0.972 ~ 1.008, more preferably in the scope of 0.975 ~ 1.006.By this, fold and lax generation can be suppressed to manufacture swimmingly meet above formula (I) and (II) and then also meet the PVA series polymer film of above formula (III).
In the manufacture method of the invention described above, final dryer roll or close to final dryer roll and final dryer roll can improve its surface temperature and be used as Heat treating roll.When dryer roll is used as Heat treating roll, roll surface temperature is preferably 90 ~ 140 DEG C, is more preferably 100 ~ 130 DEG C.
In addition, also annealing device can be provided separately with dryer roll.
Heating direction time PVA based polymer film is dry to the process of final dryer roll from the first dryer roll is not particularly limited, because can be dry by PVA based polymer film more equably, so preferably carry out drying with the front and back of the arbitrary portion of PVA based polymer film with the mode alternately contacted to each dryer roll of final dryer roll from the first dryer roll.
The PVA series polymer film having carried out above-mentioned drying process can be heat-treated as required, conditioning etc., finally coils into roll with the length of regulation, thus obtains PVA series polymer film of the present invention.
The volatile ingredient ratio of the PVA series polymer film finally obtained by above-mentioned a succession of process preferably in the scope of 1 ~ 5 quality %, more preferably in the scope of 2 ~ 4 quality %.
When manufacturing polarizing coating by PVA series polymer film of the present invention, such as, can dye to PVA series polymer film, uniaxial tension, fixing process, dry process and heat treatment as required.The order of dyeing and uniaxial tension is not particularly limited, and both can carry out dyeing process before uniaxial tension process, also can carry out dyeing with uniaxial tension process simultaneously and process, or also can carry out dyeing process after uniaxial tension process.In addition, the operation such as uniaxial tension, dyeing can be repeatedly.
The dyestuff used in dyeing as PVA series polymer film, can use iodine or dichroic organic dye (such as direct black (DirectBlack) 17,19,154; Direct brown (DirectBrown) 44,106,195,210,223; Directly red (DirectRed) 2,23,28,31,37,39,79,81,240,242,247; Direct indigo plant (DirectBlue) 1,15,22,78,90,98,151,168,202,236,249,270; Direct purple (DirectViolet) 9,12,51,98; Direct green (DirectGreen) 1,85; Direct Huang (DirectYellow) 8,12,44,86,87; The dichroic dyes such as direct orange (DirectOrange) 26,39,106,107) etc.These dyestuffs one can be used alone or be used in combination.Dyeing usually by make PVA series polymer film be immersed in containing above-mentioned dyestuff solution in carry out, its treatment conditions and processing method are not particularly limited.
The PVA series polymer film uniaxial tension that alongst (MD) stretches can be undertaken by any one method in wet type pulling method or xeothermic pulling method.When carrying out uniaxial tension by wet type pulling method, both uniaxial tension can be carried out in borated warm water, also uniaxial tension can be carried out in the solution containing above-mentioned dyestuff or in following fixing process bath, also can carry out uniaxial tension in atmosphere with the PVA series polymer film after water suction, uniaxial tension can also be carried out by other method.Draft temperature during uniaxial tension process is not particularly limited, PVA series polymer film is stretched in warm water (wet type stretching), adopt and be preferably 30 ~ 90 DEG C, be more preferably 40 ~ 70 DEG C, the more preferably temperature of 45 ~ 65 DEG C, when xeothermic stretching, adopt the temperature being preferably 50 ~ 180 DEG C.In addition, as the stretching ratio (being total stretching ratio when carrying out uniaxial tension with multistep) of uniaxial tension process, preferred until film stretches before facing fracture as much as possible from the viewpoint of polarization property, specifically be preferably more than 4 times, be more preferably more than 5 times, more preferably more than 5.5 times.As long as the upper limit film of stretching ratio does not rupture just being not particularly limited, in order to carry out homogeneous stretching, being preferably less than 8.0 times.
The thickness of the film (polarizing coating) after stretching is preferably 5 ~ 35 μm, is particularly preferably 20 ~ 30 μm.
When manufacturing polarizing coating, in order to make the absorption on the film of dyestuff after uniaxial tension firm, be mostly fixed process.The general extensive employing of fixing process is by the method for film immersion in the process bath being added with boric acid and/or boron compound.Now, iodine compound can be added as required in process bath.
Then, preferably drying process (heat treatment) is carried out to the film having carried out uniaxial tension process or uniaxial tension process and fixing process.The temperature of dry process (heat treatment) is preferably 30 ~ 150 DEG C, is particularly preferably 50 ~ 140 DEG C.Dry process (heat treatment) if temperature too low, then the dimensional stability of the polarizing coating of gained easily reduces, and on the other hand, if too high, then the reduction of polarization property easily occurs with the decomposition etc. of dyestuff.
Can be fitted in optically transparent on the two sides of the polarizing coating obtained as mentioned above or one side and there is the diaphragm of mechanical strength, thus make polarizer.As diaphragm now, use cellulose triacetate (TAC) film, cellulose acetate butyrate (CAB) (CAB) film, acrylic acid mesentery, polyester mesentery etc.In addition, as the bonding agent for diaphragm of fitting, general use PVA system bonding agent and urethane adhesive etc., wherein preferably use PVA system bonding agent.
The polarizer obtained as mentioned above can fit in glass substrate after the bonding agents such as coating acrylic acid series, and the parts as LCD device use.When polarizer is fitted in glass substrate, phase retardation film of can simultaneously fitting, viewing-angle increasing film, brightness improve film etc.
Embodiment
By the following examples the present invention is specifically described, but the present invention is not limited in any way the following examples.
In following examples and comparative example, the volatile ingredient ratio (moisture content) of the volatile ingredient ratio of masking stoste, PVA film or PVA film, each physical property of PVA film and the optical property of polarizing coating measure by the following method.
(1) the volatile ingredient ratio of masking stoste:
Try to achieve described above by above formula [iii].
(2) the volatile ingredient ratio (moisture content) of PVA film or PVA film:
Try to achieve described above by above formula [iv].
In addition, the mensuration of the volatile ingredient ratio (moisture content) of PVA film or PVA film uses the sample of width (TD) the central portion collection from the PVA film taken out by dryer roll or PVA film to carry out.
(3) the Δ n (MD) of PVA film ave:
By " " 1 " Δ n (MD) avedetermination method " method described hereinbefore in project obtains the Δ n (MD) of the central portion of the width (TD) of PVA film ave, it can be used as the Δ n (MD) of PVA film ave.
(4) the Δ n (TD) of PVA film ave:
By " " 2 " Δ n (TD) avedetermination method " method described hereinbefore in project obtains the Δ n (TD) of the central portion of the width (TD) of PVA film ave, it can be used as the Δ n (TD) of PVA film ave.
(5) the quality swellbility of PVA film:
PVA film is cut into 1.5g, floods 30 minutes in the distilled water 1000g of 30 DEG C, flood after 30 minutes and PVA film is taken out, suck the water on surface with filter paper after, measure its quality (W e).Then, this PVA film after dry 16 hours, is measured its quality (W with the drying machine of 105 DEG C f).By the quality W of gained eand W fthe quality swellbility of PVA film is obtained by following formula [v].
Quality swellbility (%)=(W e/ W f) × 100 [v].
(6) the ultimate elongation multiplying power of PVA film:
The test film of central portion acquisition length direction (MD) × width (TD)=10cm × 5cm of the width (TD) of the PVA film before the stretching obtained from following examples or comparative example, stretching clamp is fixed at the two ends of the length direction of this test film, length direction (MD) × width (TD)=5cm × 5cm is of a size of to make stretched portion, flooded for 38 seconds in the water of 30 DEG C, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (first step stretching) to after 2.2 times of raw footage, iodine is being contained with the concentration of 0.03 quality %, contain with the concentration of 3 quality % in the iodine/potassium iodide aqueous solution of the temperature 30 DEG C of KI and flooded for 90 seconds, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (second step stretching) to 3.3 times of raw footage, then, boric acid is being contained with the concentration of 3 quality %, contain with the concentration of 3 quality % in the boric acid/potassium iodide aqueous solution of the temperature 30 DEG C of KI and flooded for about 20 seconds, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (the 3rd step stretch) to 3.6 times of raw footage, then, while containing boric acid with the concentration of 4 quality %, contain with the concentration of about 5 quality % in the boric acid/potassium iodide aqueous solution of the temperature about 60 DEG C of KI and flood, while with the draw speed of 12cm/ minute alongst (MD) uniaxial tension rupture to test film, read the stretching ratio (length during fracture is relative to the ratio of raw footage) during test film fracture.
For same PVA film, carry out 5 above-mentioned tension tests, get the ultimate elongation multiplying power (doubly) of its mean value as PVA film.
(7) optical property of polarizing coating:
(i) transmissivity:
The central portion of the width of the polarizing coating obtained from following examples or comparative example and the differently-oriented directivity of polarizing coating gather the foursquare sample of 2 pieces of 1.5cm × 1.5cm abreast, for each sample respectively with the spectrophotometer V-7100 of Hitachi (subsidiary integrating sphere) with JIS Z8722 (assay method of object color) for benchmark carries out illuminant-C, the brightness correction of the visible region in 2 degree of visuals field, for 1 piece of polarizing coating sample, measure relative to tensile axis direction tilt 45 degree time the transmissivity of light and inclination-45 spend time the transmissivity of light, obtain their mean value (Y 1).
For another block polarizing coating sample, the transmissivity of the light when transmissivity of light when also as described above measuring inclination 45 degree and inclination-45 are spent, obtains their mean value (Y 2).
By the Y tried to achieve as mentioned above 1and Y 2on average, as transmissivity (Y) (%) of polarizing coating.
(ii) degree of polarization:
For the 2 pieces of polarizing coating samples gathered in above-mentioned (i), measure with the transmissivity (Y ∥) of the light during mode overlap that its differently-oriented directivity is parallel and with the transmissivity (Y ⊥) of the light during mode overlap that differently-oriented directivity is orthogonal by the method same with the assay method of above-mentioned transmissivity, obtained degree of polarization (V) (%) by following formula [vi].
Degree of polarization (V) (%)={ (Y ∥-Y ⊥)/(Y ∥+Y ⊥) } 1/2× 100 [vi].
(iii) degree of polarization during transmissivity 44.25%:
As recorded in following embodiment and comparative example, in each embodiment or comparative example, change the dip time in iodine/potassium iodide aqueous solution when second step stretches, make 5 pieces of polarizing coatings, for each polarizing coating, transmissivity (Y) and degree of polarization (V) is obtained respectively with said method, for each embodiment or comparative example, respectively with transmissivity (Y) be transverse axis, with degree of polarization (V) for 5 point-renderings are become figure by the longitudinal axis, obtain curve of approximation, the value of the degree of polarization (V) when to obtain transmissivity (Y) be 44.25% by this curve of approximation.
" embodiment 1 "
(1) manufacture of PVA film:
I masking stoste that the volatile ingredient ratio be made up of PVA (saponification degree 99.9 % by mole, the degree of polymerization 2400) 100 mass parts, glycerine 12 mass parts, lauric acid diethyl amide 0.1 mass parts and the water by being obtained by saponifying polyvinyl acetate is 66 quality % by () spues to the first dryer roll (surface temperature 93 DEG C, peripheral speed (S from T-shaped mould with membranaceous 1) 16.7m/ minute) on, while spray the hot blast of 90 DEG C on the first dryer roll with the wind speed of 5m/ second to whole first dryer roll noncontact face, while be dried to moisture content to reach 18 quality %, then, peel off from the first dryer roll, the drying after the second dryer roll is carried out under the condition of roll surface temperature about 85 DEG C, alternately contact with each dryer roll with the back side to make the surface of the arbitrary portion of PVA film, finally, after heat-treating with the final dryer roll (Heat treating roll) of surface temperature 108 DEG C, batch, obtain PVA film (thick 60 μm, wide 3m, volatile ingredient ratio 3 quality %).In this embodiment 1, dryer roll when volatile ingredient ratio reaches 13 quality % is the 7th dryer roll.
In this embodiment 1, the peripheral speed (S of the dryer roll (the 7th dryer roll) when (α) volatile ingredient ratio reaches 13 quality % t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 1.000; (β) peripheral speed (S of final dryer roll l) peripheral speed (S of dryer roll (the 7th dryer roll) when reaching 13 quality % relative to volatile ingredient ratio t) ratio (S l/ S t) be 0.974; (γ) peripheral speed (S of the second dryer roll 2) relative to the peripheral speed (S of the first dryer roll 1) ratio (S 2/ S 1) be 1.030; (δ) peripheral speed (S of next dryer roll (the 8th dryer roll) t+1) peripheral speed (S of dryer roll (the 7th dryer roll) when reaching 13 quality % relative to volatile ingredient ratio t) ratio (S t/ S t+1) be 0.998; (ε) peripheral speed (S of final dryer roll l) relative to the peripheral speed (S of the first dryer roll 1) ratio (S l/ S 1) be 0.975, make PVA film.
(ii) the Δ n (MD) of the PVA film obtained in above-mentioned (i) is measured with said method ave, Δ n (TD) ave, quality swellbility and ultimate elongation multiplying power, result is as shown in table 1 below.
(2) manufacture of polarizing coating:
The test film of central portion acquisition length direction (MD) × width (TD)=10cm × 5cm of the width (TD) of i PVA film that () obtains from above-mentioned (1), stretching clamp is fixed at the two ends of the length direction of this test film, length direction (MD) × width (TD)=5cm × 5cm is of a size of to make stretched portion, flooded for 38 seconds in the water of 30 DEG C, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (first step stretching) to after 2.2 times of raw footage, iodine is being contained with the concentration of 0.03 quality %, contain with the concentration of 3 quality % in the iodine/potassium iodide aqueous solution of the temperature 30 DEG C of KI and flooded for 60 seconds, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (second step stretching) to 3.3 times of raw footage, then, boric acid is being contained with the concentration of 3 quality %, contain with the concentration of 3 quality % in the boric acid/potassium iodide aqueous solution of the temperature 30 DEG C of KI and flooded for about 20 seconds, in the process with the draw speed of 12cm/ minute alongst (MD) uniaxial tension (the 3rd step stretch) to 3.6 times of raw footage, then, while containing boric acid with the concentration of 4 quality %, contain with the concentration of about 5 quality % in the boric acid/potassium iodide aqueous solution of the temperature about 60 DEG C of KI and flood, while with after the draw speed of 12cm/ minute alongst (MD) uniaxial tension (the 4th step stretches) to the stretching ratio faced before the ultimate elongation multiplying power reaching the PVA film measured as mentioned above, flooded for 10 seconds in the potassium iodide aqueous solution containing KI with the concentration of 3 quality %, carry out iodide ion impregnation process, then the drying machine of 60 DEG C is used dry 4 minutes, make polarizing coating (thick about 21 μm).
Obtain transmissivity (Y) and the degree of polarization (V) of the polarizing coating obtained thus with said method, by this point-rendering be transverse axis with transmissivity (Y), in the figure that is the longitudinal axis with degree of polarization (V).
(ii) in above-mentioned (i), dip time during except being stretched by second step in the iodine/potassium iodide aqueous solution of temperature 30 DEG C changes into except 75 seconds from 60 seconds, carry out the operation same with above-mentioned (i), make the polarizing coating (thick about 21 μm) of [draw speed of each draw stage is all similarly 12cm/ minute with above-mentioned (i)].
Transmissivity (Y) and the degree of polarization (V) of the polarizing coating obtained thus is obtained, by this point-rendering in the figure of above-mentioned (i) with said method.
(iii) in above-mentioned (i), dip time during except being stretched by second step in the iodine/potassium iodide aqueous solution of temperature 30 DEG C changes into except 90 seconds from 60 seconds, carry out the operation same with above-mentioned (i), make the polarizing coating (thick about 21 μm) of [draw speed of each draw stage is all similarly 12cm/ minute with above-mentioned (i)].
Transmissivity (Y) and the degree of polarization (V) of the polarizing coating obtained thus is obtained, by this point-rendering in the figure of above-mentioned (i) with said method.
(iv) in above-mentioned (i), dip time during except being stretched by second step in the iodine/potassium iodide aqueous solution of temperature 30 DEG C changes into except 105 seconds from 60 seconds, carry out the operation same with above-mentioned (i), make the polarizing coating (thick about 21 μm) of [draw speed of each draw stage is all similarly 12cm/ minute with above-mentioned (i)].
Transmissivity (Y) and the degree of polarization (V) of the polarizing coating obtained thus is obtained, by this point-rendering in the figure of above-mentioned (i) with said method.
In (v) above-mentioned (i), dip time during except being stretched by second step in the iodine/potassium iodide aqueous solution of temperature 30 DEG C changes into except 120 seconds from 60 seconds, carry out the operation same with above-mentioned (i), make the polarizing coating (thick about 21 μm) of [draw speed of each draw stage is all similarly 12cm/ minute with above-mentioned (i)].
Transmissivity (Y) and the degree of polarization (V) of the polarizing coating obtained thus is obtained, by this point-rendering in the figure of above-mentioned (i) with said method.
(vi) on figure, draw the curve of approximation drawing 5 points in the drawings in above-mentioned (i) ~ (v), the value of the degree of polarization (V) when to obtain transmissivity (Y) be 44.25% by this curve of approximation, result is as shown in table 1 below is 99.98.
" embodiment 2 ~ 5 "
(1), in embodiment 1, as recorded the film forming condition changed when manufacturing PVA film in following table 1, PVA film is manufactured in the same manner as (1) of embodiment 1.But, in example 2, as masking stoste, the volatile ingredient ratio be made up of PVA (saponification degree 99.9 % by mole, the degree of polymerization 2400) 100 mass parts, glycerine 12 mass parts, lauric acid diethyl amide 0.1 mass parts and the water by being obtained by saponifying polyvinyl acetate is used to be the masking stoste of 73 quality %.
The Δ n (MD) of each PVA film obtained thus is measured with said method ave, Δ n (TD) ave, quality swellbility and ultimate elongation multiplying power, result is as shown in table 1 below.
(2) test film of length direction (MD) × width (TD)=10cm × 5cm using the central portion of the width (TD) of each PVA film obtained from above-mentioned (1) to gather, carry out the operation same with (2) of embodiment 1, 5 kinds of polarizing coatings are manufactured respectively for each embodiment, obtain transmissivity (Y) and the degree of polarization (V) of each polarizing coating, by this point-rendering with transmissivity (Y) for transverse axis, in the figure being the longitudinal axis with degree of polarization (V), figure draws the curve of approximation of drafting 5 points in the drawings, the value of the degree of polarization (V) when to obtain transmissivity (Y) be 44.25% by this curve of approximation, result is as shown in table 1 below.
" comparative example 1 ~ 5 "
(1), in embodiment 1, as recorded the film forming condition changed when manufacturing PVA film in following table 2, PVA film is manufactured in the same manner as (1) of embodiment 1.
The Δ n (MD) of each PVA film obtained thus is measured with said method ave, Δ n (TD) ave, quality swellbility and ultimate elongation multiplying power, result is as shown in table 2 below.
(2) test film of length direction (MD) × width (TD)=10cm × 5cm using the central portion of the width (TD) of each PVA film obtained from above-mentioned (1) to gather, carry out the operation same with (2) of embodiment 1, 5 kinds of polarizing coatings are manufactured respectively for each comparative example, obtain transmissivity (Y) and the degree of polarization (V) of each polarizing coating, by this point-rendering with transmissivity (Y) for transverse axis, in the figure being the longitudinal axis with degree of polarization (V), figure draws the curve of approximation of drafting 5 points in the drawings, the value of the degree of polarization (V) when to obtain transmissivity (Y) be 44.25% by this curve of approximation, result is as shown in table 2 below.
[table 1]
[table 2]
From above-mentioned table 1 and table 2, the Δ n (MD) of the PVA film of embodiment 1 ~ 5 ave[birefringence of the length direction (MD) of PVA film on the thickness direction of film equalization and the value obtained] and Δ n (TD) ave[birefringence of the width (TD) of PVA film on the thickness direction of film equalization and the value obtained] meets formula (I) and (II), thus there are 6.72 ~ 6.94 such high limit stretching ratios, and the polarizing coating obtained by the PVA film of embodiment 1 ~ 5 has the polarization property of the equal above excellence with existing polarizing coating.
In contrast, the PVA film of comparative example 1 ~ 4 does not meet formula (I), and the PVA film of comparative example 4 and 5 does not meet formula (II), and therefore compared with the PVA film of embodiment 1 ~ 5, ultimate elongation multiplying power is all low.
When manufacturing polarizing coating by PVA series polymer film, generally for and avoid the fracture of film when stretching and carry out uniaxial tension with the stretching ratio more lower slightly than ultimate elongation multiplying power, but because the ultimate elongation multiplying power of the PVA film of embodiment 1 ~ 5 is all up to more than 6.72, so when manufacturing polarizing coating under the condition of this embodiment, the PVA film of embodiment 1 ~ 5 can carry out uniaxial tension with the high stretching ratio of more than 6 times, even if carry out with the high stretching ratio of more than 6.5 times the fracture that film also can not occur uniaxial tension, can stretch swimmingly.
In contrast, in the PVA film of comparative example 1 ~ 5, because the ultimate elongation multiplying power of the PVA film of comparative example 4 is less than 6, so when manufacturing polarizing coating under the condition of this comparative example, can not carry out uniaxial tension with the stretching ratio of more than 6 times, when stretching, film easily ruptures, in addition, the PVA film of comparative example 1 ~ 3 and 5 is when the stretching ratio uniaxial tension with more than 6 times, troubling in the fracture this point of film.
In addition, also the length of 1 volume is had to be the former film of more than 1000m in the former film of polarizing coating, such as, in the PVA series polymer film of total length 1000m, its ultimate elongation multiplying power rises 0.1 point (0.1 times), then uniaxial tension and the length of stretched film that obtains increase 100m (1000m × 0.1 times=100m), can obtain more polarizing coating by the former film of equal length.
About this point, from embodiment 1 ~ 5, the PVA film of embodiment 1 ~ 5 is compared with the PVA film of comparative example 1 ~ 5, ultimate elongation multiplying power is up to 0.10 ~ 0.98 point (doubly), such as, if the length of PVA film is 1000m, then when with PVA film, it manufactures polarizing coating under the condition of above-described embodiment, the length of polarizing coating will grow 100 ~ 980m compared with using the situation of the PVA film of comparative example 1 ~ 5, can obtain more polarizing coating.
Industrial usability
Even if PVA series polymer film of the present invention is at the thinner thickness of film, when being about 30 ~ 65 μm, also there is high limit stretching ratio, even if when manufacture polarizing coating etc. with high magnification uniaxial tension, also not easily there is the fracture of film, therefore can when not interrupting stretching operation with high finished product rate, and with drying time shorter than ever, the stretched film such as the polarizing coating of the excellent in optical properties such as polarization property are manufactured with good productivity ratio, so extremely useful as the former film for the manufacture of stretched film such as polarizing coatings, and, manufacture method of the present invention is useful as the method manufacturing this PVA series polymer film of the present invention with high production rate swimmingly continuously.

Claims (4)

1. the manufacture method of polymer film of polyvinyl alcohol, is characterized in that,
A () uses the film forming apparatus possessing the many dryer rolls that rotating shaft is parallel to each other, masking stoste containing vinol series polymer is spued to the first dryer roll of this film forming apparatus and after carrying out part drying with membranaceous, carries out drying further with follow-up dryer roll and carry out masking; Now,
Peripheral speed (the S of the dryer roll when volatile ingredient ratio of () Polyvinyl alcohol film reaches 13 quality % b t) relative to the peripheral speed (S of the first dryer roll 1) ratio (S t/ S 1) be 0.990 ~ 1.050;
Peripheral speed (the S of (c) final dryer roll l) peripheral speed (S of dryer roll when reaching 13 quality % relative to the volatile ingredient ratio of Polyvinyl alcohol film t) ratio (S l/ S t) be 0.960 ~ 0.980;
Peripheral speed (the S of (d) final dryer roll l) relative to the peripheral speed (S of the first dryer roll 1) ratio (S l/ S 1) be 0.970 ~ 1.010.
2. manufacture method according to claim 1, wherein, the volatile ingredient ratio of Polyvinyl alcohol film when peeling off from the first dryer roll is 17 ~ 30 quality %.
3. manufacture method according to claim 1 and 2, wherein, the roll surface temperature of each dryer roll is more than 65 DEG C.
4. manufacture method according to claim 1 and 2, wherein, the volatile ingredient ratio of the masking stoste containing vinol series polymer is 60 ~ 75 quality %, and the roll surface temperature of the first dryer roll is 80 ~ 120 DEG C, the peripheral speed (S of the first dryer roll 1) be 8 ~ 25m/ minute.
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