CN109153797A - Polyvinyl alcohol film and its manufacturing method and the light polarizing film for using the polyvinyl alcohol film - Google Patents

Polyvinyl alcohol film and its manufacturing method and the light polarizing film for using the polyvinyl alcohol film Download PDF

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Publication number
CN109153797A
CN109153797A CN201780028573.7A CN201780028573A CN109153797A CN 109153797 A CN109153797 A CN 109153797A CN 201780028573 A CN201780028573 A CN 201780028573A CN 109153797 A CN109153797 A CN 109153797A
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film
polyvinyl alcohol
light polarizing
alcohol film
mentioned
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CN109153797B (en
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北村秀
北村秀一
早川诚郎
早川诚一郎
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Mitsubishi Chemical Corp
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Nippon Synthetic Chemical Industry Co Ltd
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    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J5/00Manufacture of articles or shaped materials containing macromolecular substances
    • C08J5/18Manufacture of films or sheets
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/24Shaping 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
    • B29C41/26Shaping 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
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34Component parts, details or accessories; Auxiliary operations
    • B29C41/46Heating or cooling
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29CSHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
    • B29C41/00Shaping by coating a mould, core or other substrate, i.e. by depositing material and stripping-off the shaped article; Apparatus therefor
    • B29C41/34Component parts, details or accessories; Auxiliary operations
    • B29C41/52Measuring, controlling or regulating
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08LCOMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L29/00Compositions of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal or ketal radical; Compositions of hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Compositions of derivatives of such polymers
    • C08L29/02Homopolymers or copolymers of unsaturated alcohols
    • C08L29/04Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00Optical elements other than lenses
    • G02B5/30Polarising elements
    • BPERFORMING OPERATIONS; TRANSPORTING
    • B29WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
    • B29KINDEXING 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
    • B29K2029/00Use of polyvinylalcohols, polyvinylethers, polyvinylaldehydes, polyvinylketones or polyvinylketals or derivatives thereof as moulding material
    • B29K2029/04PVOH, i.e. polyvinyl alcohol
    • CCHEMISTRY; METALLURGY
    • C08ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08JWORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H
    • C08J2329/00Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
    • C08J2329/02Homopolymers or copolymers of unsaturated alcohols
    • C08J2329/04Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids

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

Abstract

The present invention provides: draftability when manufacture light polarizing film is excellent, can obtain having high degree of polarization and the few light polarizing film of irregular colour polyvinyl alcohol film, particularly slim light polarizing film manufacture when the manufacturing method of polyvinyl alcohol film and the polyvinyl alcohol film that does not also the produce fracture and light polarizing film using the polyvinyl alcohol film.Polyvinyl alcohol film of the invention is characterized in that, is the polyvinyl alcohol film of length 4km or more, the moisture rate of the film is that the stretch modulus X (MPa) of the length direction (MD) of the state of 9 weight % is 5~12MPa.

Description

Polyvinyl alcohol film and its manufacturing method and use the polyvinyl alcohol film Light polarizing film
Technical field
The present invention relates to polyvinyl alcohol film, particularly with excellent draftability, high degree of polarization and color can be obtained The polyvinyl alcohol film of uneven few light polarizing film and its manufacturing method and the light polarizing film using the polyvinyl alcohol film.
Background technique
In recent years, the development of liquid crystal display device is significant, be widely used in smart phone, tablet computer, personal computer, LCD TV, projector, vehicle-mounted panel etc..Light polarizing film has been used in above-mentioned liquid crystal display device, has mainly been used as light polarizing film There is the light polarizing film that iodine or dichroic dye are adsorbed and be orientated on polyvinyl alcohol film.In recent years, with the fine of picture Change, high brightness, enlargement, slimming need excellent, irregular colour further than the degree of polarization of existing product and wide cut are long The light polarizing film of but thin.It should be noted that the light polarizing film in the present invention is also referred to as polarizing film, polarizing film.
In general, light polarizing film manufactures as follows: the polyvinyl alcohol film as blank being solved from roller, edge flowing side It after swelling, is dyed, is stretched, to manufacture with dichroic dyes such as iodine in water (including warm water) to the conveying side (MD).On Stating stretching process is following process: the film streamwise (MD) after dyeing being stretched, keeps the dichroic dye in film high Degree orientation, but in order to improve the degree of polarization of light polarizing film, the polyvinyl alcohol film for becoming blank must be on flow direction (MD) With good draftability.
It should be noted that the sequence as manufacture light polarizing film, also implements to stretch and dye opposite example.That is, to make Polyvinyl alcohol film as blank is stretched after swelling in water (including warm water), is contaminated with dichroic dyes such as iodine The example of color, in above-mentioned example, in order to improve the degree of polarization of light polarizing film, polyvinyl alcohol film also must be in flow direction (MD) there is good draftability on.For example, when tensile stress is excessive, can not carry out stretching until defined stretching ratio, two Color dyestuff will not be sufficiently orientated, and therefore, have the tendency that degree of polarization will not improve.On the contrary, when tensile stress is too small, even if into Row stretches until defined stretching ratio, the orientation of dichroic dye is also unstable, has and generates irregular colour in light polarizing film Tendency.
On the other hand, as the polyvinyl alcohol film of blank generally by the water-soluble of the polyvinyl alcohol resin as raw material Liquid is manufactured by continuous casting process.Specifically, by the aqueous solution curtain coating of polyvinyl alcohol resin in casting such as casting drum, annulus It is film-made on mold, by the film being film-made after casting die removing, while being conveyed on flow direction (MD) with nip rolls etc. While being dried with hot-rolling, as needed, be heat-treated making using floated drying machine (floating dryer) etc. It makes.In above-mentioned conveying operation, the film being film-made due to being stretched on flow direction (MD), polyethenol series high score Son is easy to be orientated on flow direction (MD), if above-mentioned orientation is excessive, on the flow direction (MD) of polyvinyl alcohol film Draftability reduce, the polarizing properties of final light polarizing film can reduce.
In turn, in recent years for the slimming of light polarizing film, polyvinyl alcohol film is also thinned, previous polyethylene Alcohol system film with a thickness of 60 μm or so, but thickness becomes 45 μm or so at present, and the foreseeable future is estimated to become 30 μm.It is above-mentioned thin The stretching when polyvinyl alcohol film of type there are problems that due to manufacture light polarizing film and the productivities such as can be broken.
The gimmick of draftability as improvement polyvinyl alcohol film, such as propose: when polyvinyl alcohol film is film-made The ratio of the speed of casting drum and final film coiling speed is set as the gimmick of specific ratio (referring for example to patent document 1);The gimmick for making film swim after being film-made on casting drum and drying (referring for example to patent document 2);It is thin to control polyethenol series The gimmick of pulled out condition in the drying process of film (referring for example to patent document 3).
In addition, it is also proposed that: reduce the polyvinyl alcohol film of phase difference in face (referring for example to patent document 4);Make Flow direction (MD) and the tensile elongation of width direction (TD) are to be equal and the polyvinyl alcohol film that manufactures is (referring for example to special Sharp document 5);Young's modulus (stretch modulus) is reduced to 20MPa polyvinyl alcohol film below by electromagnetic wave irradiation (referring for example to patent document 6) etc..
Existing technical literature
Patent document
Patent document 1: Japanese Unexamined Patent Publication 2001-315141 bulletin
Patent document 2: Japanese Unexamined Patent Publication 2001-315142 bulletin
Patent document 3: Japanese Unexamined Patent Publication 2002-79531 bulletin
Patent document 4: Japanese Unexamined Patent Publication 2006-291173 bulletin
Patent document 5: Japanese Unexamined Patent Publication 2002-30164 bulletin
Patent document 6: Japanese Unexamined Patent Publication 2013-97232 bulletin
Summary of the invention
Problems to be solved by the invention
However, even if using above patent document gimmick, improvement manufacture light polarizing film when polyvinyl alcohol film drawing Stretching property is also insufficient.
Stretching on the flow direction (MD) when the specific manufacture polyvinyl alcohol film of the public technology of above patent document 1 Long rate degree (pulled out condition), but if not considering drying condition, heat treatment condition, then the draftability of polyvinyl alcohol film obtains Less than abundant improvement.
In the public technology of above patent document 2, although the film evenly drying after film can be made, it is unable to control drawing Modulus is stretched, the draftability of polyvinyl alcohol film when manufacturing light polarizing film cannot be improved sufficiently.
In the public technology of above patent document 3, although the uniform film thickness of film can be made, it is unable to control stretching die The draftability of amount, polyvinyl alcohol film when manufacturing light polarizing film cannot be improved sufficiently.
In the public technology of above patent document 4, although phase difference in the face of film can be reduced, in control stretching die There are rooms for improvement in terms of the improvement of the draftability of polyvinyl alcohol film when amount and manufacture light polarizing film.In addition, this public affairs It opens in the manufacturing method of technology, which is characterized in that the film after drying (70 DEG C), heat treatment (120 DEG C) is temporarily cooled to 50 DEG C hereinafter, batching before rolling up film, is heated again with 50~100 DEG C, but heating process is complicated, existed in terms of productivity Room for improvement.
In the public technology of above patent document 5, although the tensile elongation of polyvinyl alcohol film can be made to stabilize, It is to be unable to control stretch modulus itself, the draftability of polyvinyl alcohol film when manufacturing light polarizing film cannot be improved sufficiently.
In the public technology of above patent document 6, although stretch modulus can be reduced, stretch modulus is in embodiment 13.8~17.8MPa, not carry out in the comparative example of electromagnetic wave irradiation stretch modulus be 27MPa, it is expected that stretch modulus is further It reduces.
It should be noted that only describing 50 μm of thickness or more of polyethylene in the embodiment of above patent document 1~6 Alcohol system film, in order to cope with the expectation of slimming in recent years, it is expected that further improving.
Therefore, the present invention provides in this context: manufacture light polarizing film when draftability it is excellent polyethenol series it is thin Film and capable of obtaining has the polyvinyl alcohol film of high degree of polarization and the few light polarizing film of irregular colour, particularly forms thickness When 25 μm of thin gauge films below, polyvinyl alcohol film and its manufacturer that when manufacture of slim light polarizing film does not also produce fracture Method and the light polarizing film for using the polyvinyl alcohol film.
The solution to the problem
Thus, the inventors of the present invention further investigate repeatedly in view of the foregoing, and as a result find out: the length of flow direction (MD) is The polyvinyl alcohol for particular range is controlled more than specific length and by the stretch modulus of the flow direction (length direction, MD) Draftability when being thin film fabrication light polarizing film is excellent, and energy yield rate manufactures slim light polarizing film well.And find: using above-mentioned The light polarizing film that polyvinyl alcohol film obtains becomes the light polarizing film few with high degree of polarization and irregular colour.
That is, the 1st purport of the invention is a kind of polyvinyl alcohol film, which is characterized in that it is the poly- of length 4km or more Ethenol system film, the moisture rate of the film be the stretch modulus X (MPa) of the length direction (MD) of the state of 9 weight % be 5~ 12MPa。
In addition, the 2nd purport of the invention is the manufacturing method of the polyvinyl alcohol film of above-mentioned 1st purport, feature exists In having following process: the aqueous solution of polyvinyl alcohol resin is filmed using continuous casting process for film making process;It is dry Process makes the film drying through being film-made;With heat treatment procedure is heat-treated the dried film, above-mentioned back tender It is in sequence, make the film drying through above-mentioned film 100 DEG C of temperature or more, above-mentioned heat treatment procedure is will be through above-mentioned drying Film cooling to after 50 DEG C or less, the processes that are heated with 60~99 DEG C.
Moreover, the 3rd purport of the invention is a kind of light polarizing film, which is characterized in that it is the poly- second using above-mentioned 1st purport Obtained from enol system film.
The effect of invention
Length direction of the polyvinyl alcohol film of 1st purport of the invention due to the state that moisture rate is 9 weight % (MD) stretch modulus X is 5~12MPa, and therefore, draftability when manufacturing light polarizing film is excellent, plays and manufactures slim light polarizing film When the effect that can not produce fracture.
In particular, the thickness D of above-mentioned film is 5~25 μm, under thickness D (μm) and above-mentioned stretch modulus X (MPa) satisfaction In the case where stating formula (1), the effect of the raising of fracture resistance when being able to achieve manufacture light polarizing film is played.
0.4≤X/D≤0.6···(1)
Wherein, the moisture rate of above-mentioned film be 9 weight % state width direction (TD) stretch modulus Y (MPa), with In the case that the above-mentioned stretch modulus X (MPa) of length direction (MD) meets following formula (2), when performance is able to achieve manufacture light polarizing film Draftability improve effect.
0.7≤Y/X≤1.3···(2)
In addition, performance can prevent from manufacturing slim in the case that the tensile strength F of length direction (MD) is 100MPa or more Light polarizing film when fracture effect.
In turn, the refractive index of length direction (MD) is set as nx, the refractive index of width direction (TD) is set as ny, thickness direction Refractive index be set as nz, when thickness is set as D (μm), the phase difference Rth of the thickness direction calculated with following formula (3) is 80~ In the case where 140nm, playing can be such that the swellability of thickness direction optimizes and draftability when manufacturing light polarizing film can be made to optimize Effect.
Rth={ (nx+ny)/2-nz } × 1000 × D (3)
Moreover, playing the effect for being able to achieve the raising of productivity in the case that the width of above-mentioned film is 4m or more.
The manufacturing method of the polyvinyl alcohol film of 2nd purport of the invention is due to having specific drying process and Re Chu Science and engineering sequence, therefore, playing can manufacture: the poly- second of draftability and excellent above-mentioned 1st purport of fracture resistance when manufacturing light polarizing film The effect of enol system film.
Polyvinyl alcohol film of the light polarizing film of 3rd purport of the invention due to using above-mentioned 1st purport, it plays The effect for embodying high degree of polarization and irregular colour capable of being made to lack.
Specific embodiment
Hereinafter, the present invention is described in detail.
Polyvinyl alcohol film of the invention is characterized in that, is the polyvinyl alcohol film of length 4km or more, at this The stretch modulus X for the length direction (MD) that the moisture rate of film measures in the state of being 9 weight % is 5~12MPa.
Moreover, side conveys along its length (MD), and side is by swelling process and drawing for above-mentioned polyvinyl alcohol film Process etc. is stretched, light polarizing film is formed in.Herein, above-mentioned polyvinyl alcohol film is specific length (4km or more) and the polyethylene Alcohol system film, the length direction (MD) that is measured in the state that moisture rate is 9 weight % be specific stretch modulus X (5~ 12MPa), therefore, the draftability when manufacture light polarizing film of above-mentioned polyvinyl alcohol film is excellent, manufactures the feelings of slim light polarizing film It is not also produced fracture under condition.Moreover, gained light polarizing film, which becomes, embodies high degree of polarization, and irregular colour lacks person.
Firstly, the above-mentioned stretch modulus to polyvinyl alcohol film of the invention is illustrated.
Stretch modulus in the present invention refers to, according to JIS K7127:1999, measures in the environment of 20 DEG C of 65%RH Value.It should be noted that stretch modulus is also referred to as Young's modulus, drawing coefficient.
In addition, the moisture rate in the present invention refers to, by the atmosphere temperature using drying machine by polyvinyl alcohol film at 105 DEG C The value that the weight of 16 hours front and backs calculates has been dried under degree, when the weight after the weight before drying is set as A, is dried is set as B, with Following formula calculates.
Moisture rate (weight %)=100 × (A-B)/A
It has been observed that polyvinyl alcohol film is stretched after swelling in the manufacturing process of light polarizing film, but be difficult to it is accurate and steady Surely the stretch modulus after measuring swelling.In the present invention, in view of the water of the polyvinyl alcohol film generally for manufacturing light polarizing film Dividing rate is number %, and stretch modulus when using moisture rate 9 weight % easily controlled by humidity regulation is index.
The gimmick of above-mentioned humidity regulation is not particularly limited, such as passes through the relatively dry polyvinyl alcohol after just manufacturing It is that film carries out humidity regulation a few houres~tens hour in the environment of 20 DEG C of 65%RH, so as to close to above-mentioned environment Under equilibrium water conten rate 9 weight % when stabilize moisture rate.It should be noted that in the present invention, above-mentioned " 9 weight of moisture rate Amount % " is the meaning for including " in the range of moisture rate is ± 0.5 weight % of 9.0 weight % ", in the range, stretch modulus base This does not change.In addition, the moisture rate in film is with the equilibrium water conten rate variation dependent on ambient humidity, therefore, moisture rate quilt Humidity regulation is the test film of 9 weight % quickly for the measurement of stretch modulus.
In the present invention, moisture rate is that Δ X is fluctuated in the face of the stretch modulus X of the length direction (MD) of the state of 9 weight % (MPa) and moisture rate is fluctuation Δ Y (MPa) in the face of the stretch modulus Y (MPa) of the width direction (TD) of the state of 9 weight % It is preferred that 5MPa or less, particularly preferred 3MPa or less, further preferred 2MPa or less.
When fluctuating that fluctuation Δ Y is excessive in Δ X and face in above-mentioned face, is generated when manufacturing light polarizing film and stretch unevenness, had in polarisation The tendency of irregular colour is generated in film.
Herein, the manufacturing method of polyvinyl alcohol film of the invention is illustrated.That is, polyethenol series of the invention The manufacturing method of film is characterized in that having following process: film making process (A), using continuous casting process by polyethenol series The aqueous solution of resin is filmed;Drying process (B) makes the film drying through being film-made;With heat treatment procedure (C), to the warp Dry film is heat-treated, in above-mentioned drying process (B), make the film drying through above-mentioned film 100 DEG C of temperature More than, in above-mentioned heat treatment procedure (C), it will be added through the film cooling of above-mentioned drying to after 50 DEG C or less, with 60~99 DEG C Heat.
(film making process (A))
Firstly, aforementioned film making process (A) is described in detail.
Polyvinyl alcohol resin used in the present invention, usually using unmodified polyvinyl alcohol resin, will It polymerize the resin that the polyvinyl acetate that vinyl acetate obtains is saponified and is manufactured.It also can be used acetic acid as needed Vinyl acetate and on a small quantity (the usual %'s or less of 10 moles of % or less, preferably 5 moles) can be with the ingredient of vinyl acetate copolymerization Resin obtained from copolymer is saponified.As can be enumerated for example unsaturated with the ingredient of vinyl acetate copolymerization Olefines (such as ethylene, propylene, n-butene, the isobutene of carboxylic acid (for example including salt, ester, amide, nitrile etc.), carbon number 2~30 Deng), vinyl ethers, unsaturated sulfonic acid salt etc..It is obtained alternatively, it is also possible to use for the hydroxyl after saponification to be chemically modified Modified polyvinylalcohol system resin.
In addition, the polyethenol series tree that side chain has 1,2- diol structure also can be used as polyvinyl alcohol resin Rouge.Above-mentioned side chain has the polyvinyl alcohol resin of 1,2- diol structure for example by (i) by vinyl acetate and 3,4- diethyl The method of the copolymer saponification of acyloxy -1- butylene, (ii) are by the copolymer soap of vinyl acetate and vinyl ethylene carbonate Change and the method for decarboxylation, (iii) are total to vinyl acetate and 2,2- dialkyl group -4- vinyl -1,3- dioxolane Polymers is saponified and takes off ketalization method, the method that the copolymer of vinyl acetate and allylin is saponified by (iv) Etc. obtaining.
The weight average molecular weight of polyvinyl alcohol resin is preferably 100,000~300,000, further preferred 110,000~280,000, especially It is preferred that 120,000~260,000.There are the tendencies that the degree of polarization of light polarizing film reduces if above-mentioned weight average molecular weight is too small, if excessive deposit The tendency that stretching when manufacturing light polarizing film using polyvinyl alcohol film becomes difficult.It should be noted that above-mentioned polyethylene The weight average molecular weight of alcohol system resin is the weight average molecular weight measured using GPC-MALS method.
The mean saponification degree of polyvinyl alcohol resin used in the present invention be preferably generally 98 moles of % or more, further It is preferred that 99 moles of % or more, particularly preferred 99.5 moles of % or more, particularly preferred 99.8 moles of % or more.If above-mentioned average saponification Spend it is small, then exist light polarizing film degree of polarization reduce tendency.
Herein, the mean saponification degree in the present invention is measured according to JIS K 6726.
Modified type, modified amount, Weight-average molecular can be applied in combination in polyvinyl alcohol resin used in the present invention The different two or more polyvinyl alcohol resins such as amount, mean saponification degree.
Further it is preferred that cleaning for above-mentioned polyvinyl alcohol resin using water equal solvent, centrifugal separator is used Etc. being dehydrated, 50 weight % of moisture content polyvinyl alcohol resin wet cake below is formed.If moisture content is excessive, exist It is difficult to form the tendency of desired concentration of aqueous solution.
So that above-mentioned polyvinyl alcohol resin wet cake is dissolved in warm water, hot water, prepares polyvinyl alcohol resin aqueous solution.
The preparation method of polyvinyl alcohol resin aqueous solution is not particularly limited, for example, heated multiscrew can be used Extrusion mechanism is standby, alternatively, it is also possible to put into aforementioned polyethylene in the dissolving tank for having upper and lower recycle stream generation type stirring blade Alcohol system resin wet cake, is blown into vapor in tank, to dissolve and prepare the aqueous solution of expectation concentration.
In the aqueous solution of polyvinyl alcohol resin, other than polyvinyl alcohol resin, from the system of polyvinyl alcohol film Preferably also contain glycerol, two polyglycereol, three polyglycereol, ethylene glycol, triethylene glycol, polyethylene glycol, three hydroxyl first from the viewpoint of film property The usually used plasticizer such as base propane, at least one of nonionic, anionic property and cationic surfactant.
It is preferably glycerol as above-mentioned plasticizer, content of the plasticizer in polyvinyl alcohol resin aqueous solution is preferred 1~20 weight %.
It is preferably polyoxyethylene alkyl amine, higher fatty acid alkanol amide as above-mentioned surfactant, the surface is living Content preferably 0.01~1 weight % of the property agent in polyvinyl alcohol resin aqueous solution.
The resin concentration of the obtained polyvinyl alcohol resin aqueous solution be preferably 15~60 weight %, further preferably 17~55 weight %, particularly preferred 20~50 weight %.Drying load increases if the resin concentration of above-mentioned aqueous solution is too low, because This is excessively high there are viscosity if excessively high and be difficult to the tendency of uniform dissolution there are the tendency that production capacity reduces.
Then, deaeration processing is carried out for obtained polyvinyl alcohol resin aqueous solution.As defoaming method, can enumerate The methods of standing and defoaming, the deaeration carried out using the multi-screw extruder with exhaust outlet out.As more spiral shells with exhaust outlet Bar extruder, usually using the double screw extruder with gas vent.
After deaeration processing, polyvinyl alcohol resin aqueous solution is with a certain amount of casting for being directed into T-type slit die, being discharged in rotation It on drum and is cast, is filmed by continuous casting process.
Preferably 80~100 DEG C of the temperature of the polyvinyl alcohol resin aqueous solution of T-type slit die outlet, particularly preferred 85~98 ℃.If the temperature of above-mentioned polyvinyl alcohol resin aqueous solution is too low, existing becomes to flow undesirable tendency, if excessively high, Then there is the tendency of foaming.
The viscosity of above-mentioned polyvinyl alcohol resin aqueous solution in discharge preferably 50~200Pas, it is particularly preferred 70~ 150Pa·s.If the viscosity of above-mentioned aqueous solution is too low, existing becomes to flow undesirable tendency, if excessively high, there is stream Prolong the tendency become difficult.
From T-type slit die to the velocity of discharge preferably 0.1~3.0m/ points of the polyvinyl alcohol resin aqueous solution of casting drum discharge It is clock, 0.2~2.5m/ minutes particularly preferred, 0.3~2.0m/ minutes further preferred.If the above-mentioned velocity of discharge is excessively slow, deposit In the tendency that productivity reduces, if too fast, there is the tendency that curtain coating becomes difficult.
Diameter preferably 2~5m, the particularly preferred 2.4~4.5m, further preferred 2.8~4m of above-mentioned casting drum.It is above-mentioned straight If diameter is too small, has the tendency that dry long deficiency, is difficult to generate speed, if excessive, have the tendency that transporting reduction.
The preferred 4m or more of width of above-mentioned casting drum, particularly preferred 4.5m or more, further preferred 5m or more, particularly preferably 5~6m.If the width for drum of casting is too small, has the tendency that productivity reduction.
The revolving speed preferably 1~30m/ minutes of above-mentioned casting drum, 2~25m/ minutes particularly preferred, further preferred 3~20m/ Minute.If above-mentioned revolving speed is excessively slow, has the tendency that productivity reduction, if too fast, have the tendency that dehydration becomes inadequate.
It is preferably 40~99 DEG C of the surface temperature of above-mentioned casting drum, 50~90 DEG C more preferable, 55~80 DEG C particularly preferred.It is above-mentioned If surface temperature is too low, have the tendency that as poor dewatering, if excessively high, having the tendency that foam.
Film made of so carrying out aforementioned film making process (A) and being film-made can be from casting drum removing.
(drying process (B))
Then, aforementioned drying process (B) is described in detail.The drying process (B) is will be through the film of above-mentioned film The process for heating and drying.
It is defeated by using the streamwises such as nip rolls (MD) from the film (film through above-mentioned film) after casting drum removing It send and contacts the surface of the film and the back side alternately with multiple hot-rollings, to be dried.Preferably, hot-rolling is using for example For surface has been carried out the processing of plating hard chrome or mirror surface treatment and 0.2~2m of diameter roller and usually using 2~30, preferably It is dried using 10~25.
Preferably 100 DEG C or more of drying temperature (temperature for making the film drying through above-mentioned film), particularly preferred 100~120 DEG C, it is 100~115 DEG C further preferred, 100~110 DEG C particularly preferred.If above-mentioned drying temperature is too low, have as drying Undesirable tendency has the tendency that leading to the bad orders such as bending if excessively high.It should be noted that the drying in the present invention Temperature be using hot-rolling in the highest temperature hot-rolling surface temperature.
Drying time is not particularly limited, usually 1~60 second, preferably 2~50 seconds, it is 3~40 seconds particularly preferred, further It is preferred that 4~30 seconds.If drying time is too short, have the tendency that as underdry, if too long, having causes bending etc. outer See undesirable tendency.
It should be noted that the drying time in the present invention refers to the hot-rolling of the highest temperature and connecing for the film through above-mentioned film The time is touched, in the case that the hot-rolling of the above-mentioned highest temperature there are more, for the integrated value with the time of contact of these hot-rollings.
The moisture rate of film after drying preferably 5 weight % or less, particularly preferred 0.1~4 weight %, further preferably 0.2~3 weight %, particularly preferred 0.3~2.5 weight %.If above-mentioned moisture rate is excessively high, there is finally obtained polyvinyl alcohol It is the tendency that film becomes underdry.
(heat treatment procedure (C))
Then, aforementioned heat treatment procedure (C) is described in detail.The heat treatment procedure (C) is to through above-mentioned drying The process that film is heat-treated.Any process that above-mentioned heat treatment procedure generally carries out as needed, the present invention in, become For controlling process necessary to stretch modulus.That is, in the heat treatment procedure (C), it will be in above-mentioned drying process (B) with 100 DEG C or more it is dry after film be temporarily cooled to 50 DEG C or less (temperature of the film itself through above-mentioned drying), again with 60~99 It DEG C is heated, so that stretch modulus be made to become desired range, improves draftability when manufacture light polarizing film.
As above-mentioned cooling means, for example, placing and making the natural cooling of its natural cooling;Blow cold wind Method etc..
As above-mentioned heating means, for example, the method for blowing hot wind with floated drying machine;It is contacted with hot-rolling Method etc., in the present invention, stretch modulus stabilized aspect, it is preferable to use floated drying machine method.
It is preferably 65~95 DEG C of heating temperature, 70~90 DEG C particularly preferred, 70~80 DEG C further preferred.Above-mentioned heating temperature If too low, have the tendency that stretch modulus reduction, if excessively high, has the tendency that stretch modulus increase.It should be noted that In the case that above-mentioned heating means are the method for blowing hot wind with above-mentioned floated drying machine, the heating temperature in the present invention refers to The temperature of the hot wind, in the case that above-mentioned heating means are the method contacted with above-mentioned hot-rolling, the heating temperature in the present invention is Refer to the surface temperature of the hot-rolling.
Heating time is not particularly limited, in the case where using floated drying machine, preferably 10~120 seconds, particularly preferably 20~90 seconds, it is 30~60 seconds further preferred.If above-mentioned heating time is too short, there is inclining for the fluctuation increase of stretch modulus To, if too long, have the tendency that productivity reduction.
The moisture rate of film after heating preferably 0.1~2 weight %, particularly preferred 0.2~1.7 weight %, further it is excellent Select 0.3~1.5 weight %.If above-mentioned moisture rate is too low, have the tendency that manufacture light polarizing film when it is water-swellable become difficult, on the contrary Ground has the tendency that finally obtained polyvinyl alcohol film becomes underdry if excessively high.
It is such as above-mentioned, drying process (B) and heat treatment procedure (C) are illustrated, both in the manufacturing method of the present invention Temperature equalization is important, and the drying temperature in drying process (B) is preferably the boiling point of water or more i.e. 100 DEG C or more, above-mentioned temperature In region, lower temperature is more preferably selected, in turn, the heating temperature in heat treatment procedure (C) is especially preferably less than the boiling of water Point is lower than 100 DEG C.
(polyvinyl alcohol film)
It is available longer on flow direction (MD) by above-mentioned drying process (B) and above-mentioned heat treatment procedure (C) Polyvinyl alcohol film of the invention.The polyvinyl alcohol film cuts its both ends, is batched in core pipe with web-like.
The width of the obtained polyvinyl alcohol film of the invention is mentioning the preferred 4m or more of large-duty aspect, Avoid the more preferable 4~6m of aspect of fracture.
In addition, it is premise that the length of polyvinyl alcohol film of the invention, which is 4km or more, in reply light polarizing film and then liquid The preferred 5km or more of aspect larger in area of brilliant picture, particularly preferred 5~50km in terms of conveying weight.
For the thickness D of polyvinyl alcohol film, in terms of the slimming of light polarizing film, preferably 30 μm hereinafter, into one Walk particularly preferred 25 μm of the aspect of slimming hereinafter, further preferred 5~25 μm in terms of avoiding fracture, it is particularly preferred 5~ 20μm。
Above-mentioned thickness D (μm) can according in polyvinyl alcohol resin aqueous solution resin concentration, to the row of casting die Output (velocity of discharge), stretching ratio etc. and adjust.
For polyvinyl alcohol film of the invention, when the thickness D of film is 5~25 μm, thickness D (μm), at this The moisture rate of film is the stretch modulus X (MPa) of the flow direction (MD) of the state estimating of 9 weight % from when manufacturing light polarizing film The aspect that fracture resistance improves preferably satisfies following formula (1).
0.4≤X/D≤0.6···(1)
In terms of draftability raising when manufacturing light polarizing film, particularly preferably meet following formula (1').
0.45≤X/D≤0.55···(1')
For polyvinyl alcohol film of the invention, moisture rate is the stretching of the width direction (TD) of the state of 9 weight % Following formula (2) are preferably satisfied in terms of draftability raising of the modulus Y (MPa) when manufacturing light polarizing film.
0.7≤Y/X≤1.3···(2)
In terms of draftability raising when manufacturing light polarizing film, particularly preferably meet following formula (2').
0.75≤Y/X≤1.1···(2')
If the value of above-mentioned Y/X is too small, have the tendency that the draftability of the flow direction (MD) when manufacturing light polarizing film reduces, It is on the contrary if excessive, have the tendency that draftability destabilization.
The moisture rate of polyvinyl alcohol film of the invention is the tensile strength of the flow direction (MD) of the state of 9 weight % F (MPa) preferably 100MPa or more, particularly preferred 110MPa or more.Above-mentioned tensile strength F (MPa) has manufacture thin if too small The tendency of fracture is easy to produce when the light polarizing film of type.It should be noted that the upper limit value of tensile strength F (MPa) is usually 200MPa。
In addition, the refractive index of length direction (MD) is set as nx, width direction for polyvinyl alcohol film of the invention (TD) when refractive index is set as ny, the refractive index of thickness direction is set as nz, thickness is set as D (μm), with the thickness of following formula (3) calculating Spend phase difference Rth (nm) preferably 80~140nm in direction.More preferable 85~130nm, further preferred 90~120nm.
The phase difference Rth (nm) of above-mentioned thickness direction has the tendency that the swellability of thickness direction reduces, such as if too small Fruit is excessive, then the planar orientation of macromolecular chain is strong, therefore, has the tendency that draftability when manufacturing light polarizing film reduces.
Rth={ (nx+ny)/2-nz } × 1000 × D (3)
It should be noted that in above embodiment, to use drum (drum type roller) of casting to be as the case where casting die The method of manufacture polyvinyl alcohol film is illustrated in example, but also can be used and pour Cast Strip, resin film as pouring mold Tool is to manufacture.
Polyvinyl alcohol film of the invention is since draftability is excellent, it is therefore especially preferred that being used as the blank of light polarizing film.
Herein, the manufacturing method of the light polarizing film for using polyvinyl alcohol film of the invention to obtain is illustrated.
(manufacturing method of light polarizing film)
For light polarizing film of the invention by exporting above-mentioned polyvinyl alcohol film from roller and transferring in the horizontal direction, process is molten The processes manufacture such as swollen, dyeing, boric acid crosslinking, stretching, cleaning, dry.
Swelling process is implemented before dyeing process.By being swollen process, polyvinyl alcohol film surface can be cleaned Dirt also has the effect of preventing dyeing uneven in addition to this by being swollen polyvinyl alcohol film.It is swollen in process, makees For treatment fluid, usually used water.A small amount of iodinated compounds can be added in above-mentioned treatment fluid if main component is water, surface is lived Additives, the alcohol such as property agent etc..The temperature of swelling bath is usually 10~45 DEG C or so, and the dip time to swelling bath is usually 0.1 ~10 minutes or so.
Dyeing process is carried out by contacting polyvinyl alcohol film with the liquid containing iodine or dichroic dye.Usually Using the aqueous solution of iodine-potassium iodide, the concentration of iodine is 0.1~2g/L, the concentration of potassium iodide is that 1~100g/L is suitable.Dye It is practical that the color time, which is 30~500 seconds or so,.The temperature of processing bath is preferably 5~50 DEG C.In aqueous solution, in addition to aqueous solvent with It outside can be also containing a small amount of organic solvent with water with compatibility.
Boric acid cross-linking process step is carried out by using boron compounds such as boric acid, boraxs.Boron compound is organic with aqueous solution or water- Stabilisation of the potassium iodide from polarizing properties coexists with 10~100g/L of concentration or so use in the form of solvent mixed liquor in a liquid From the viewpoint of preferably.Temperature when preferred process is 30~70 DEG C or so, the processing time is 0.1~20 minute or so, in addition It can according to need and carry out stretched operation in processes.
Stretching process stretches 3~10 times, preferably 3.5~6 times preferably on uniaxial direction (flow direction (MD)).At this point, Can also the right angle orientation of draw direction carry out several stretchings (prevent the contraction of width direction (TD) degree or its with On stretching).Temperature when stretching is preferably 30~170 DEG C.In turn, stretching ratio is finally set in aforementioned range, Stretched operation can only be implemented once, can also implement in manufacture polarisation membrane process multiple.
In the present invention, it has been observed that the tensile stress in above-mentioned stretching process is necessary for range appropriate.That is, tensile stress When excessive, it can not carry out stretching until defined stretching ratio, dichroic dye will not be sufficiently orientated, therefore, have degree of polarization not The tendency that can be improved.On the contrary, when tensile stress is too small, even if stretch until defined stretching ratio, dichroic dye Orientation it is also unstable, have the tendency that in light polarizing film generate irregular colour.
It should be noted that tensile stress is set according to each thickness in general, manufacturing in polarisation membrane process, because This, it is difficult to make preferred range generalization, but in the comparison under same thickness, tensile stress is preferably made to reduce by one into above, spy One is not preferably reduced into~tri- one-tenth.
Cleaning process is for example carried out by impregnating polyvinyl alcohol film in the iodide aqueous solution such as water, potassium iodide, The precipitate for resulting from the polyvinyl alcohol film surface can be removed.Iodate potassium concn when using potassium iodide aqueous solution is 1 ~80g/L or so.Temperature when cleaning treatment is usually 5~50 DEG C, preferably 10~45 DEG C.Handling the time is usually 1~300 Second, preferably 10~240 seconds.It should be noted that water cleans and can be appropriately combined using the cleaning of potassium iodide aqueous solution.
Drying process for example by above-mentioned polyvinyl alcohol film in an atmosphere, come within dry 1~10 minute at 40~80 DEG C into Row.
So obtain light polarizing film of the invention.The degree of polarization of light polarizing film of the invention preferably 99.5% or more, more preferably 99.8% or more.If degree of polarization is too low, has the tendency that the contrast being unable to ensure in liquid crystal display.
It should be noted that usually degree of polarization calculate as follows, by 2 light polarizing films using its differently- oriented directivity as the same direction Light transmittance (H is measured under mode overlap condition under wavelength X11), 2 light polarizing films are being formed into mutually orthogonal side with differently- oriented directivity To mode overlap condition under under wavelength X measure light transmittance (H1), by light transmittance (H11) and light transmittance (H1) calculate according to the following formula Above-mentioned degree of polarization out.
Degree of polarization=[(H11-H1)/(H11+H1)]1/2
In turn, the single plate transmission of light polarizing film of the invention preferably 42% or more, more preferable 43% or more.Above-mentioned monolithic is saturating If penetrated, rate is too low, has the tendency that the high brightness of liquid crystal display can not be reached.
Single plate transmission is value obtained from the light transmittance using spectrophotometric determination light polarizing film monolithic.
Light polarizing film of the invention is suitable for manufacturing that degree of polarization is excellent, polarizer without irregular colour.
Herein, the manufacturing method for the polarizer for using light polarizing film of the invention is illustrated.
(manufacturing method of polarizer)
Above-mentioned polarizer is bonded via bonding agent optically respectively to same by the one or two sides in light polarizing film of the invention The resin film of property makes as protective film.As protective film, such as cellulosic triacetate, cellulose can be enumerated Diacetate esters, polycarbonate, polymethyl methacrylate, cyclic olefin polymer, cyclic olefine copolymer, polystyrene, polyether sulfone, The film or sheet material of poly (arylene ether) ester, poly- 4- methylpentene, polyphenylene oxide etc..
Applying method is carried out using known gimmick, such as by the way that the adhesive composite of liquid is equably coated on polarisation After film, protective film or the two, the two is bonded and carries out pressurized adhesion, heating irradiates active energy beam to carry out.
Alternatively, it is also possible to be coated with polyurethane series resin, acrylic resin, carbamide resin etc. in the one or two sides of light polarizing film Curable resin carries out being solidified to form cured layer, forms polarizer.It operates if so, then above-mentioned cured layer becomes above-mentioned guarantor The substitution for protecting film, may be implemented filming.
It is excellent in terms of polarizing properties using the light polarizing film of polyvinyl alcohol film of the invention, polarizer, it is preferred for Portable information terminal, personal computer, TV, projector, billboard, desk-top electronic calculator, electronic watch, at text Manage mechanical, electrical sub- paper, game machine, video recorder, camera, photograph album, thermometer, sound equipment, automobile, mechanical metrical instrument class etc. Liquid crystal display device, sunglasses, anti-dazzle spectacles, anaglyph spectacles, wearable display, display element (CRT, LCD, organic EL, electricity Sub- paper etc.) use anti-reflection layer, fiber optic communication instrument, Medical Instruments, construction material, toy etc..
Embodiment
Further progress of the present invention is illustrated hereinafter, enumerating embodiment, as long as but the present invention is no more than its purport It is not limited by following embodiment then.
Moreover, such as following characteristic (moisture rate, drawing for carrying out embodiment and the polyvinyl alcohol film in comparative example below Stretch modulus, tensile strength, the phase difference of thickness direction, tensile stress) and light polarizing film characteristic (degree of polarization, single plate transmission, face Color is uneven) measurement and evaluation.
< determination condition >
(moisture rate (weight %))
The test film that 100mm × 100mm is cut out from gained polyvinyl alcohol film by initial weight A (g) and utilizes Drying machine has dried the weight B (g) after 16 hours under 105 DEG C of atmosphere temperature, calculates moisture rate (weight by following formula Measure %).
Moisture rate (weight %)=100 × (A-B)/A
(stretch modulus (MPa), tensile strength F (MPa))
The test film that 120mm × 15mm is cut out from gained polyvinyl alcohol film, in the Constant Temperature and Humidity Chambers of 20 DEG C of 65%RH In, after progress humidity regulation makes moisture rate become ± 0.5 weight % of 9 weight %, use Shimadzu Scisakusho Ltd's system " essence Close universal testing machine, Autograph (AG-IS) ", according to JIS K7127:1999 (between tensile speed 1000mm/ minutes, chuck Distance 50mm), in the environment of 20 DEG C of 65%RH, measure the stretch modulus X (MPa) and width direction (TD) of flow direction (MD) Stretch modulus Y (MPa).Moreover, being measured tensile strength F (MPa) for flow direction (MD).
(the phase difference Rth (nm) of thickness direction)
From the central portion of the width direction (TD) of gained polyvinyl alcohol film and both ends (in the 10cm of film end Side) cut-out length 4cm × width 4cm test film, using measuring difference of phases device, (" KOBRA-WR " prince measures machine strain formula Commercial firm's system), measure under 590nm, thickness direction phase difference Rth (nm).
The determination condition > of < Rth
Incidence angle: 50 °
Tilt central axis: slow axis
Mean refractive index: the numerical value measured using Abbe refractomecer
(tensile stress (N))
From gained polyvinyl alcohol film cut-out length (length direction (MD)) 50mm × width (width direction (TD)) The test film of 35mm, in such a way that distance between chuck becomes 20mm, by the chuck of the both ends width 35mm of length direction (MD) After clamping, impregnated 60 seconds in 25 DEG C of warm water, and (MD) is stretched to 1.7 times (34mm) along its length, then at 28 DEG C (MD) is stretched to 1.6 times (54.4mm) along its length in dyeing liquor, in 55 DEG C of borate along its length (MD) finally 2.05 times (111.5mm) are stretched to, with the tension (N) of spring scale measurement at this time.The composition of the dyeing liquor and borate that use is such as It is lower described.
Dyeing liquor: iodine 0.9g/L, potassium iodide 30g/L
Borate: potassium iodide 30g/L, boric acid 25g/L
(degree of polarization (%), single plate transmission (%))
Central portion and both side ends (each end of the two side ends apart from light polarizing film from the width direction (TD) of gained light polarizing film 10cm inside) cut-out length 4cm × width 4cm test film, use automatic polarizing film measurement device (Japan light splitting strain Formula commercial firm system: VAP7070), measure degree of polarization (%) and single plate transmission (%).For in the flow direction (MD) of light polarizing film Centre portion and front end/terminal part (inside of each end 10m of front end and terminal apart from light polarizing film) carry out said determination.
(irregular colour)
Central portion and both side ends (each end of the two side ends apart from light polarizing film from the width direction (TD) of gained light polarizing film 10cm inside) cut-out length 30cm × width 30cm test film, 2 that crossed Nicol state is sandwiched in 45 ° of angle After opening between polarizer (single plate transmission 43.5%, degree of polarization 99.9%), using the lamp box of surface illuminance 14000lx, with saturating The irregular colour of mode observation optically is crossed, is evaluated according to benchmark below.
(evaluation criteria)
Zero ... does not have irregular colour
× ... there are irregular colours
Above-mentioned evaluation for the flow direction (MD) of light polarizing film central portion and front end/terminal part (apart from light polarizing film On the inside of the 10m of front end and terminal respectively held) it carries out.
1 > of < embodiment
(production of polyvinyl alcohol film)
Be put into weight average molecular weight 142000, the polyvinyl alcohol resin 1000kg of 99.8 moles of % of saponification degree, water 2500kg, As the glycerol 120kg of plasticizer, warming while stirring carries out concentration to adjust to resin concentration being 25 weight %, obtain to 140 DEG C To the polyvinyl alcohol resin aqueous solution equably dissolved.Then, above-mentioned polyvinyl alcohol resin aqueous solution is supplied to having After the double screw extruder of exhaust outlet carries out deaeration, aqueous temperature is set as 95 DEG C, from the discharge (discharge of T-type slit die outlet Speed 0.8m/ minutes) and the casting drum of rotation is cast to be film-made.By the film through being film-made from casting drum removing, while making The surface and the back side of the film replace contact edge with 20 hot-rollings and are dried.Drying temperature (the surface temperature of the hot-rolling of the highest temperature Degree) it is 120 DEG C, drying time (time of contact of the hot-rolling and film of the highest temperature accumulative) is 12 seconds.It then, will be through above-mentioned dry Dry film carries out natural cooling, thus after the temperature of the film itself is temporarily cooled to 40 DEG C, using floated drying machine, 75 DEG C of hot wind 60 seconds is blowed from above-mentioned film two sides and is heated, and the polyvinyl alcohol film (thickness of 1 weight % of moisture rate is obtained 20 μm, width 5m, length 5km).Finally, the both ends of the polyvinyl alcohol film are cut, batched with web-like in core pipe.It will The characteristic of the above-mentioned polyvinyl alcohol film of gained is shown in following tables 1.
(manufacture of light polarizing film)
It solves gained polyvinyl alcohol film from roller to convey in the horizontal direction using conveying roller, firstly, side is impregnated in water The sink of 25 DEG C of temperature makes its swelling side streamwise (MD) in 1 minute be stretched to 1.7 times.Then, while being impregnated in comprising iodine 0.9g/L, potassium iodide 30g/L 28 DEG C of aqueous solution in dyed, edge flow direction (MD) is stretched to 1.6 times, then, While be impregnated in comprising boric acid 25g/L, potassium iodide 30g/L 55 DEG C of aqueous solution in carry out boric acid crosslinking, edge flow direction (MD) it carries out being uniaxially stretched to 2.0 times.Finally, being cleaned with potassium iodide aqueous solution, with 50 DEG C of progress drying in 2 minutes, obtain The light polarizing film of total 5.6 times of stretching ratio.Do not cause to be broken in the manufacture of above-mentioned light polarizing film.In addition, by the spy of gained light polarizing film Property is shown in following tables 2.
< embodiment 2,1 > of comparative example
It is manufactured under the conditions of shown in following tables 1, in addition to this, obtains polyvinyl alcohol similarly to Example 1 It is film and light polarizing film.The characteristic of gained polyvinyl alcohol film is shown in following tables 1, the characteristic of gained light polarizing film is shown in down The table 2 stated.
It should be noted that having attempted the manufacture of light polarizing film similarly to Example 1, but boric acid is crosslinked work in comparative example 1 It is broken in stretching in sequence.The characteristic of table 2 is only the characteristic of gained light polarizing film front end.
[table 1]
[table 2]
The polyvinyl alcohol film of Examples 1 and 2 since the value of stretch modulus is in specific range of the invention, because This, the degree of polarization of gained light polarizing film is high, without irregular colour, and the stretch modulus of the polyvinyl alcohol film of comparative example 1 is in this hair Outside bright specific range, thus, it can be known that being easily broken off, the degree of polarization of gained light polarizing film is poor, there is irregular colour.
In addition, in the same manner as in the above embodiment 1, having made the polyvinyl alcohol film of length 4km, 10km.For these The polyvinyl alcohol film of length has obtained also embodying the result being similarly inclined to above-described embodiment 1,2.
In above-described embodiment, the concrete mode in the present invention is shown, but above-described embodiment only simple illustration, And non-limiting explanation.Obvious deformation is within the scope of the invention to those skilled in the art.
Industrial availability
It is excellent in terms of polarizing properties using the light polarizing film of polyvinyl alcohol film of the invention, polarizer, it is preferred for Portable information terminal, personal computer, TV, projector, billboard, desk-top electronic calculator, electronic watch, at text Manage mechanical, electrical sub- paper, game machine, video recorder, camera, photograph album, thermometer, sound equipment, automobile, mechanical metrical instrument class etc. Liquid crystal display device, sunglasses, anti-dazzle spectacles, anaglyph spectacles, wearable display, display element (CRT, LCD, organic EL, electricity Sub- paper etc.) use anti-reflection layer, fiber optic communication instrument, Medical Instruments, construction material, toy etc..

Claims (8)

1. a kind of polyvinyl alcohol film, which is characterized in that it is the polyvinyl alcohol film of length 4km or more, the film Moisture rate is that the stretch modulus X of the length direction (MD) of the state of 9 weight % is 5~12MPa.
2. polyvinyl alcohol film according to claim 1, which is characterized in that the thickness D of the film is 5~25 μm, Thickness D (μm) and the stretch modulus X (MPa) meet following formula (1),
0.4≤X/D≤0.6···(1)。
3. polyvinyl alcohol film according to claim 1 or 2, which is characterized in that the moisture rate of the film is 9 weights The stretch modulus X (MPa) of the stretch modulus Y (MPa) and length direction (MD) that measure the width direction (TD) of the state of % are full Sufficient following formula (2),
0.7≤Y/X≤1.3···(2)。
4. polyvinyl alcohol film described in any one of claim 1 to 3, which is characterized in that length direction (MD) Tensile strength F is 100MPa or more.
5. polyvinyl alcohol film according to any one of claims 1 to 4, which is characterized in that by length direction (MD) Refractive index be set as nx, the refractive index of width direction (TD) is set as ny, the refractive index of thickness direction is set as nz, thickness is set as D (μ When m), with the phase difference Rth of the thickness direction of following formula (3) calculating for 80~140nm,
Rth={ (nx+ny)/2-nz } × 1000 × D (3).
6. polyvinyl alcohol film according to any one of claims 1 to 5, which is characterized in that the width of the film For 4m or more.
7. a kind of manufacturing method of polyvinyl alcohol film according to any one of claims 1 to 6, which is characterized in that have Following process: the aqueous solution of polyvinyl alcohol resin is filmed using continuous casting process for film making process;Drying process makes The film drying through being film-made;With, heat treatment procedure is heat-treated the dried film, in the drying process, Make 100 DEG C of temperature or more of the film drying through the film, the heat treatment procedure be will the film through the drying it is cold But to 50 DEG C or less processes that are rear, being heated with 60~99 DEG C.
8. a kind of light polarizing film, which is characterized in that it is using polyvinyl alcohol film described in any one of claim 1~6 Obtained from.
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