WO2016208652A1 - Film à base d'alcool polyvinylique, procédé de production d'un film à base d'alcool polyvinylique, et film polarisant - Google Patents

Film à base d'alcool polyvinylique, procédé de production d'un film à base d'alcool polyvinylique, et film polarisant Download PDF

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Publication number
WO2016208652A1
WO2016208652A1 PCT/JP2016/068598 JP2016068598W WO2016208652A1 WO 2016208652 A1 WO2016208652 A1 WO 2016208652A1 JP 2016068598 W JP2016068598 W JP 2016068598W WO 2016208652 A1 WO2016208652 A1 WO 2016208652A1
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Prior art keywords
polyvinyl alcohol
film
alcohol film
water
tension
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PCT/JP2016/068598
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English (en)
Japanese (ja)
Inventor
裕一 寺本
早川　誠一郎
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日本合成化学工業株式会社
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Application filed by 日本合成化学工業株式会社 filed Critical 日本合成化学工業株式会社
Priority to JP2016542783A priority Critical patent/JP6883990B2/ja
Priority to KR1020177033815A priority patent/KR102475405B1/ko
Priority to CN201680029754.7A priority patent/CN107614578A/zh
Publication of WO2016208652A1 publication Critical patent/WO2016208652A1/fr

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Classifications

    • 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
    • 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
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08K—Use of inorganic or non-macromolecular organic substances as compounding ingredients
    • C08K5/00—Use of organic ingredients
    • C08K5/04—Oxygen-containing compounds
    • C08K5/05—Alcohols; Metal alcoholates
    • C08K5/053—Polyhydroxylic alcohols
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L29/00—Compositions 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
    • C08L29/02—Homopolymers or copolymers of unsaturated alcohols
    • C08L29/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids
    • 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
    • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
    • G02B5/00—Optical elements other than lenses
    • G02B5/30—Polarising elements
    • G02B5/3025—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state
    • G02B5/3033—Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state in the form of a thin sheet or foil, e.g. Polaroid
    • 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
    • C08J2329/00—Characterised by the use of homopolymers or copolymers of compounds having one or more unsaturated aliphatic radicals, each having only one carbon-to-carbon double bond, and at least one being terminated by an alcohol, ether, aldehydo, ketonic, acetal, or ketal radical; Hydrolysed polymers of esters of unsaturated alcohols with saturated carboxylic acids; Derivatives of such polymer
    • C08J2329/02—Homopolymers or copolymers of unsaturated alcohols
    • C08J2329/04—Polyvinyl alcohol; Partially hydrolysed homopolymers or copolymers of esters of unsaturated alcohols with saturated carboxylic acids

Definitions

  • the present invention relates to a polyvinyl alcohol film. More specifically, a polyvinyl alcohol film for producing a polarizing film excellent in dyeability and stretchability as a raw material of the polarizing film and excellent in polarizing performance, a production method thereof, and the polyvinyl alcohol film
  • the present invention relates to a polarizing film obtained by use.
  • the polarizing film is produced by dyeing and stretching a polyvinyl alcohol film as a raw material with a pigment such as iodine.
  • a pigment such as iodine.
  • a polyvinyl alcohol film is swollen with warm water, dyed with iodine, stretched to arrange iodine molecules, cross-linked with a cross-linking agent such as boric acid to maintain the stretched state, washed, And dried.
  • the steps of water swelling, dyeing, stretching, and boric acid crosslinking may be switched in order or a plurality of steps may be performed simultaneously. What is common is that the polyvinyl alcohol film is continuously unwound from the roll, applied with appropriate tension in the flow direction using a winder or nip roll, and conveyed in the horizontal direction. .
  • Such a polarizing film is used as a basic component of liquid crystal display devices such as portable information terminals and televisions.
  • liquid crystal display devices such as portable information terminals and televisions.
  • polarizing films having high light transmittance and high degree of polarization.
  • liquid crystal televisions have become larger and thinner, conventional products have been demanded.
  • polarizing film that is wider, longer, and thinner.
  • a wide, long and thin polyvinyl alcohol-based film having excellent dyeability and stretchability is required.
  • the dyeability of the polyvinyl alcohol film is low, a sufficient degree of polarization cannot be obtained, and polarization unevenness tends to occur.
  • the stretchability of the polyvinyl alcohol-based film is low, breakage occurs in the manufacturing process of the polarizing film, so that a wide, long and thin polarizing film cannot be manufactured. As a matter of course, continuous production is interrupted by breakage, and the productivity of the polarizing film is greatly reduced.
  • the stretchability is low, the dye is not sufficiently oriented, and thus the degree of polarization tends to decrease or polarization unevenness tends to occur.
  • Patent Documents 1 and 2 In order to improve the dyeability of a polyvinyl alcohol film, a technique for controlling the bath temperature in the swelling process has been proposed (see, for example, Patent Documents 1 and 2). Moreover, a polarizing plate using a polyvinyl alcohol film having a specific range of stretchability has been proposed (see, for example, Patent Document 3).
  • Patent Document 3 defines a stress (tension) when a polyvinyl alcohol film is stretched 4 to 6 times in water.
  • the water temperature is often around 30 ° C., which is a relatively low temperature in processes such as swelling and dyeing, and around 50 ° C., which is a relatively high temperature, in processes such as stretching and boric acid crosslinking.
  • a polyvinyl alcohol film that can be obtained is provided.
  • the present inventors have made a polyvinyl alcohol solution obtained by discharging and casting an aqueous solution of a polyvinyl alcohol resin into a cast mold and continuously drying it.
  • the polyvinyl alcohol film produced by paying attention to the underwater tension at a higher temperature of 50 ° C. is particularly wide so that when the film is stretched in water at different temperatures, the underwater tension is in a specific range. It has been found that a polarizing film having a high degree of polarization and no polarization unevenness can be produced even when it is made thin.
  • the gist of the present invention is that the tension when stretched 6 times in the flow direction of the film (MD direction) in water of thickness D (mm) and 30 ° C. is A (N / mm 2 ) and water in 50 ° C.
  • the following formulas (1) and (2) are satisfied when the tension when stretched 6 times in the film flow direction (MD direction) is B (N / mm 2 ): the film.
  • the present invention also provides a method for producing the polyvinyl alcohol film and a polarizing film obtained using the polyvinyl alcohol film.
  • the polyvinyl alcohol film of the present invention is excellent in dyeability and stretchability, and has a high degree of polarization even in the case of being wide, long and thin, and can obtain a polarizing film free from uneven polarization. Can produce a polarizing film with high productivity.
  • the polyvinyl alcohol film of the present invention has a thickness of D (mm) and a tension of A (N / mm 2 ) and 50 ° C. when stretched 6 times in the film flow direction (MD direction) in 30 ° C. water.
  • a polyvinyl alcohol film satisfying the following formulas (1) and (2) when the tension when stretched 6 times in the film flow direction (MD direction) in water is B (N / mm 2 ).
  • Formula (1 ′) 0.65 ⁇ D ⁇ A ⁇ 1.15
  • Formula (2 ′) 0.25 ⁇ D ⁇ B ⁇ 0.39
  • Particularly preferred is a polyvinyl alcohol film satisfying the following formulas (1 ′′) and (2 ′′).
  • Formula (1 ′′) 0.7 ⁇ D ⁇ A ⁇ 1.1
  • Formula (2 ′′) 0.27 ⁇ D ⁇ B ⁇ 0.38
  • the value of the thickness D of the polyvinyl alcohol film is 0.04 mm or less in terms of thinning the polarizing film. It is preferably 0.03 mm or less from the viewpoint of further thinning the polarizing film, and more preferably from 0.01 to 0.03 mm from the viewpoint of avoiding breakage of the polarizing film.
  • the polyvinyl alcohol film of the present invention preferably satisfies the following formula (3), particularly preferably satisfies the following formula (3 ′), and more preferably satisfies the following formula (3 ′′).
  • Formula (3) 0.2 ⁇ B / A ⁇ 0.5 Formula (3 ′) 0.25 ⁇ B / A ⁇ 0.4 Formula (3 ′′) 0.3 ⁇ B / A ⁇ 0.35
  • the polyvinyl alcohol film of the present invention preferably has a tension A of 15 to 40 N / mm 2 when stretched 6 times in the film flow direction (MD direction) in water at 30 ° C., particularly preferably. Is 18 to 35 N / mm 2 , more preferably 20 to 30 N / mm 2 . If the value of the tension A is too low, the film tends to be deformed in the swelling process or the dyeing process, and if it is too high, sufficient dyeing tends to be difficult in the dyeing process.
  • the polyvinyl alcohol film of the present invention preferably has a tension B value of 3 to 15 N / mm 2 when stretched 6 times in the film flow direction (MD direction) in water at 50 ° C., Particularly preferred is 4 to 12 N / mm 2 , and more preferred is 5 to 10 N / mm 2 . If the value of the tension B is too low, the degree of polarization when the polarizing film is formed tends to decrease, and if it is too high, breakage tends to occur during the production of the polarizing film.
  • the polyvinyl alcohol film of the present invention has an E2 / E1 value of 0 when the storage elastic modulus in water at 30 ° C. is E1 (Pa) and the storage elastic modulus in water at 50 ° C. is E2 (Pa). It is preferably from 25 to 0.30, particularly preferably from 0.26 to 0.29. If the value of E2 / E1 is too low, the polarization degree of the obtained polarizing film tends to decrease, and if it is too high, breakage tends to occur during the production of the polarizing film.
  • the polyvinyl alcohol film of the present invention preferably has a storage elastic modulus E1 in water of 30 ° C. of 9 to 12 MPa from the viewpoint of transportability. Further, the storage elastic modulus E2 in water at 50 ° C. is preferably 2 to 4 MPa from the viewpoint of transportability.
  • a method for producing a polyvinyl alcohol film of the present invention that is, an aqueous solution of a polyvinyl alcohol resin is discharged and cast into a cast mold to form a film, and continuously dried to produce a polyvinyl alcohol film. A method will be described.
  • an unmodified polyvinyl alcohol resin that is, a resin produced by saponifying polyvinyl acetate obtained by polymerizing vinyl acetate is usually used. If necessary, a resin obtained by saponifying a copolymer of vinyl acetate and a small amount (usually 10 mol% or less, preferably 5 mol% or less) of a copolymerizable component with vinyl acetate may be used. it can.
  • components copolymerizable with vinyl acetate include unsaturated carboxylic acids (including salts, esters, amides, nitriles, etc.), and olefins having 2 to 30 carbon atoms (eg, ethylene, propylene, n-butene). , Isobutene, etc.), vinyl ethers, unsaturated sulfonates and the like.
  • the modified polyvinyl alcohol-type resin obtained by chemically modifying the hydroxyl group after saponification can also be used.
  • a polyvinyl alcohol resin having a 1,2-diol structure in the side chain can be used as the polyvinyl alcohol resin.
  • a polyvinyl alcohol resin having a 1,2-diol structure in the side chain includes, for example, (i) a method of saponifying a copolymer of vinyl acetate and 3,4-diacetoxy-1-butene, and (ii) acetic acid.
  • the weight average molecular weight of the polyvinyl alcohol resin is preferably 100,000 to 300,000, particularly preferably 110,000 to 280,000, and more preferably 120,000 to 260,000. If the weight average molecular weight is too small, sufficient optical performance tends to be difficult to obtain when the polyvinyl alcohol-based resin is used as an optical film, and if it is too large, it is difficult to stretch the polyvinyl alcohol-based film during the production of the polarizing film. Tend.
  • the weight average molecular weight of the polyvinyl alcohol resin is a weight average molecular weight measured by GPC-MALS method.
  • the average saponification degree of the polyvinyl alcohol resin used in the present invention is usually preferably 98 mol% or more, particularly preferably 99 mol% or more, further preferably 99.5 mol% or more, and particularly preferably 99.mol%. It is 8 mol% or more. If the average degree of saponification is too small, there is a tendency that sufficient optical performance cannot be obtained when a polyvinyl alcohol film is used as a polarizing film.
  • the average saponification degree in the present invention is measured according to JIS K 6726.
  • polyvinyl alcohol resin used in the present invention two or more kinds having different modified species, modified amount, weight average molecular weight, average saponification degree, etc. may be used in combination.
  • the polyvinyl alcohol-based film of the present invention is prepared by preparing a polyvinyl alcohol-based resin aqueous solution (film forming stock solution) using the polyvinyl alcohol-based resin, and discharging and casting the aqueous solution into a cast mold. It can manufacture continuously by drying, for example, is manufactured by the following processes.
  • Step (A) A step of preparing a polyvinyl alcohol resin aqueous solution.
  • Step (B) A step of casting an aqueous solution of a polyvinyl alcohol resin into a cast mold to form a film.
  • Step (C) A step of heating and drying the formed film by bringing it into contact with a plurality of metal heating rolls.
  • Process (D) The process of heat-processing the obtained film using a hot air.
  • examples of the cast mold include a cast drum (drum mold roll), an endless belt, and the like.
  • the cast mold is preferably performed from the viewpoint of widening, lengthening, and film thickness uniformity.
  • a case where the cast mold is a cast drum will be described as an example.
  • step (A) will be described.
  • the polyvinyl alcohol-based resin described above is washed with water and dehydrated using a centrifuge to obtain a polyvinyl alcohol-based resin wet cake having a water content of 50% by weight or less. It is preferable. When the water content is too large, it tends to be difficult to obtain a desired aqueous solution concentration. Such polyvinyl alcohol resin wet cake is dissolved in warm water or hot water to prepare a polyvinyl alcohol resin aqueous solution.
  • the method for preparing the polyvinyl alcohol-based resin aqueous solution is not particularly limited.
  • the polyvinyl alcohol-based resin aqueous solution may be prepared by using a heated multi-screw extruder.
  • the polyvinyl alcohol-based resin wet cake thus prepared is charged and water vapor is blown into the can to prepare an aqueous solution having a desired concentration and dissolution.
  • the latter is preferable from the viewpoint of improving the degree of polarization, and it is more preferable to prepare the solution by pressure dissolution at 120 ° C. or higher.
  • the polyvinyl alcohol-based resin aqueous solution may contain a plasticizer and at least one surfactant of nonionic, anionic, and cationic properties as necessary. It is preferable from the point.
  • plasticizer used in the present invention examples include glycerin, diglycerin, triglycerin, ethylene glycol, triethylene glycol, polyethylene glycol, and trimethylolpropane.
  • glycerin is preferable because of its low cost.
  • the blending amount is preferably 5 to 12% by weight, particularly preferably 6 to 11.5% by weight, and more preferably 7 to 11% with respect to the polyvinyl alcohol resin. If the amount is too small, the underwater tension of the polyvinyl alcohol film tends to increase, and if too large, the underwater tension of the polyvinyl alcohol film tends to be insufficient.
  • the surfactant used in the present invention is preferably an anionic surfactant from the viewpoint of compatibility with an aqueous polyvinyl alcohol resin solution.
  • the resin concentration of the aqueous polyvinyl alcohol resin solution thus obtained is preferably 15 to 60% by weight, particularly preferably 17 to 55% by weight, and further preferably 20 to 50% by weight. If the resin concentration is too low, the drying load increases, so the production capacity tends to decrease. If the resin concentration is too high, the viscosity becomes too high and uniform dissolution tends to be difficult.
  • the polyvinyl alcohol resin aqueous solution is defoamed.
  • Examples of the defoaming method include static defoaming and defoaming by a multi-screw extruder having a vent.
  • a multi-screw extruder having a vent a twin-screw extruder having a vent is usually used.
  • the polyvinyl alcohol-based resin aqueous solution is introduced into a T-shaped slit die by a certain amount, discharged and cast on a rotating cast drum, and formed into a film by a casting method.
  • the resin temperature of the T-type slit die discharge port is preferably 80 to 100 ° C., particularly preferably 85 to 99 ° C. If the resin temperature is too low, the flow tends to be poor, and if it is too high, the resin tends to foam.
  • the viscosity of the aqueous polyvinyl alcohol resin solution is preferably 50 to 200 Pa ⁇ s, particularly preferably 70 to 150 Pa ⁇ s, at the time of discharge.
  • the viscosity of the aqueous solution is too low, the flow tends to be poor, and when it is too high, casting tends to be difficult.
  • the discharge speed of the aqueous polyvinyl alcohol resin solution discharged from the T-type slit die onto the cast drum is preferably 0.2 to 5 m / min, particularly preferably 0.4 to 4 m / min, and more preferably 0.8. 6-3 m / min. If the discharge speed is too slow, the productivity tends to decrease, and if it is too fast, casting tends to be difficult.
  • Casting is preferably performed with a cast drum from the viewpoint of widening, lengthening, and film thickness uniformity.
  • a cast drum usually, a surface of stainless steel (SUS) whose main component is iron is subjected to metal plating to prevent damage.
  • SUS stainless steel
  • the metal plating include chrome plating, nickel plating, and zinc plating, and these are used alone or in a laminate of two or more layers. Among these, it is preferable that the outermost surface is chrome plating from the viewpoint of durability of the drum surface.
  • the width of the cast drum is preferably 4 m or more, particularly preferably 5 m or more. If the width of the cast drum is too small, it tends to be difficult to obtain a wide film.
  • the diameter of the cast drum is preferably 2 to 5 m, particularly preferably 2.4 to 4.5 m, and more preferably 2.8 to 4 m. If the diameter is too small, the drying length is insufficient and the speed tends not to be obtained, and if it is too large, the transportability tends to decrease.
  • the rotational speed of the cast drum is preferably 3 to 50 m / min, particularly preferably 4 to 40 m / min, and further preferably 5 to 35 m / min. If the rotational speed is too slow, the productivity tends to decrease, and if it is too fast, drying tends to be insufficient.
  • the surface temperature of the cast drum is preferably 40 to 99 ° C, particularly preferably 60 to 95 ° C. If the surface temperature is too low, drying tends to be poor, and if it is too high, foaming tends to occur.
  • Step (C) is a step of heating and drying the formed film by bringing it into contact with a plurality of metal heating rolls.
  • the drying of the polyvinyl alcohol film formed on the cast drum is performed by bringing the front and back surfaces of the film into contact with a plurality of metal heating rolls alternately.
  • the surface temperature of the metal heating roll is not particularly limited, but is usually 60 to 150 ° C., more preferably 70 to 140 ° C. If the surface temperature is too low, drying tends to be poor, and if the surface temperature is too high, drying tends to be excessive, and appearance defects such as undulation tend to be caused.
  • the temperature of the plurality of metal heating rolls is preferably in the order of the following conditions (a) to (d) from the viewpoint of controlling the underwater tension of the polyvinyl alcohol film.
  • Condition (d) ⁇ 100 ° C In general, the number of metal heating rolls is 10 to 30, and is appropriately set so as to satisfy the above temperature condition.
  • step (D) After drying with a metal heating roll, the obtained film is heat-treated using hot air in the step (D). Next, the step (D) will be described.
  • the heat treatment temperature is preferably 110 to 140 ° C., particularly preferably 115 to 135 ° C., and further preferably 120 to 130 ° C. If the heat treatment temperature is too low, the underwater tension of the polyvinyl alcohol film tends to be insufficient, and if it is too high, the underwater tension of the polyvinyl alcohol film tends to increase. As a method of such heat treatment, a method using a floating dryer is preferable in terms of excellent temperature control.
  • the film that has been heat-treated is slit at both ends and wound into a roll to form a roll-shaped polyvinyl alcohol film.
  • the width of the polyvinyl alcohol film is preferably 4 m or more from the viewpoint of widening the polarizing film, particularly preferably 4.5 m or more from the viewpoint of further widening, and more preferably from the viewpoint of avoiding breakage. 4.5 to 6 m.
  • the length of the polyvinyl alcohol film is preferably 4 km or more from the viewpoint of increasing the area of the polarizing film, particularly preferably 4.5 km or more, more preferably from the viewpoint of transport weight. From 4.5 to 50 km.
  • the above-mentioned polyvinyl alcohol film has a tension of 40 to 80 N / mm 2 when stretched four times in the film flow direction (MD direction) in the atmosphere of 20 ° C. and 65% RH in terms of windability. It is preferred, particularly preferably, a point at 43 ⁇ 75N / mm 2 of stability during storage, and more preferably from 46 ⁇ 70N / mm 2 from the ease of control of the water tension.
  • the above-mentioned polyvinyl alcohol film preferably has an in-plane retardation of 50 nm or less, particularly preferably 40 nm or less, and more preferably 30 nm or less, from the viewpoint of uniformity of tension in water.
  • the polyvinyl alcohol film of the present invention is obtained.
  • the polyvinyl alcohol film of the present invention is excellent in optical performance, is suitably used as an optical polyvinyl alcohol film, and is particularly preferably used as a raw material for a polarizing film.
  • the polarizing film of the present invention is produced through steps such as swelling, dyeing, boric acid crosslinking, stretching, washing, and drying by unwinding the polyvinyl alcohol film from a roll and transferring it in the horizontal direction.
  • the swelling process is performed before the dyeing process.
  • water is usually used as the treatment liquid.
  • the treatment solution may contain a small amount of an iodide compound, an additive such as a surfactant, alcohol, or the like.
  • the temperature of the swelling bath is usually about 10 to 45 ° C., and the immersion time in the swelling bath is usually about 0.1 to 10 minutes. Moreover, you may perform extending
  • the dyeing step is performed by bringing the film into contact with a liquid containing iodine or a dichroic dye.
  • a liquid containing iodine or a dichroic dye usually, an iodine-potassium iodide aqueous solution is used.
  • the iodine concentration is suitably 0.1-2 g / L, and the potassium iodide concentration is 1-100 g / L.
  • the dyeing time is practically about 30 to 500 seconds.
  • the temperature of the treatment bath is preferably 5 to 50 ° C.
  • the aqueous solution may contain a small amount of an organic solvent compatible with water in addition to the aqueous solvent. Moreover, you may perform extending
  • the boric acid crosslinking step is performed using a boron compound such as boric acid or borax.
  • the boron compound is used in the form of an aqueous solution or a water-organic solvent mixture at a concentration of about 10 to 100 g / L, and it is preferable that potassium iodide coexists in the solution from the viewpoint of stabilizing the polarization performance.
  • the temperature during the treatment is preferably about 30 to 70 ° C., and the treatment time is preferably about 0.1 to 20 minutes. If necessary, the stretching operation may be performed during the treatment.
  • the stretching step it is preferable to stretch 3 to 10 times, preferably 3.5 to 6 times in a uniaxial direction.
  • a slight stretching may be performed in a direction perpendicular to the stretching direction.
  • the temperature during stretching is preferably 30 to 170 ° C.
  • the draw ratio may be finally set within the above range, and the drawing operation may be performed not only in one stage but also in any stage of the manufacturing process.
  • the washing step is performed, for example, by immersing a polyvinyl alcohol film in an aqueous solution of iodide such as water or potassium iodide, thereby removing deposits generated on the surface of the film.
  • iodide such as water or potassium iodide
  • the concentration of potassium iodide may be about 1 to 80 g / L.
  • the temperature during the washing treatment is usually 5 to 50 ° C., preferably 10 to 45 ° C.
  • the treatment time is usually 1 to 300 seconds, preferably 10 to 240 seconds.
  • the drying process may be performed in the atmosphere at 40 to 80 ° C. for 1 to 10 minutes.
  • the polarization degree of the polarizing film is preferably 99.5% or more, more preferably 99.8% or more. If the degree of polarization is too low, there is a tendency that the contrast in the liquid crystal display cannot be secured.
  • the degree of polarization is generally the light transmittance (H 11 ) measured at the wavelength ⁇ in the state where two polarizing films are overlapped so that their orientation directions are the same direction, and the two polarizing films. It is calculated according to the following equation from the light transmittance (H 1 ) measured at the wavelength ⁇ in a state where the films are superposed so that the orientation directions are orthogonal to each other. [(H 11 ⁇ H 1 ) / (H 11 + H 1 )] 1/2
  • the single transmittance of the polarizing film of the present invention is preferably 42% or more. If the single transmittance is too low, it tends to be impossible to achieve high brightness of the liquid crystal display.
  • the single transmittance is a value obtained by measuring the light transmittance of a single polarizing film using a spectrophotometer.
  • the polarizing film of the present invention is obtained, the polarizing film of the present invention is suitable for producing a polarizing plate with little color unevenness.
  • the manufacturing method of the polarizing plate of this invention is demonstrated.
  • the polarizing film of the present invention is bonded to one side or both sides of an optically isotropic resin film as a protective film via an adhesive to form a polarizing plate.
  • protective films include films of cellulose triacetate, cellulose diacetate, polycarbonate, polymethyl methacrylate, cycloolefin polymer, cycloolefin copolymer, polystyrene, polyethersulfone, polyarylene ester, poly-4-methylpentene, polyphenylene oxide, and the like. Or a sheet.
  • the bonding method is performed by a known method. For example, after a liquid adhesive composition is uniformly applied to a polarizing film, a protective film, or both, the two are bonded and pressure-bonded, and heated or activated. This is done by irradiating energy rays.
  • a curable resin such as urethane resin, acrylic resin, urea resin or the like is applied to one side or both sides of the protective film and cured to obtain a polarizing plate.
  • a polarizing film comprising a polyvinyl alcohol film obtained by the production method of the present invention is excellent in in-plane uniformity of polarization performance, and is a portable information terminal, personal computer, TV, projector, signage, electronic desk calculator, electronic timepiece.
  • Word processors electronic paper, game machines, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as automobile and machinery instruments, sunglasses, anti-glare glasses, stereoscopic glasses, wearable displays, display elements (CRT) , LCD, organic EL, electronic paper, etc.) for use in antireflection layers, optical communication equipment, medical equipment, building materials, toys and the like.
  • In-plane retardation (nm) A test piece having a length (MD direction) of 20 cm ⁇ width (TD direction) of 20 cm was cut out from the obtained polyvinyl alcohol film, and a two-dimensional birefringence evaluation system (manufactured by Photonic Lattice: “PA-110L”) was used. In-plane retardation (nm) was measured.
  • Polarization unevenness From the obtained polarizing film, a test piece having a length of 30 cm and a width of 30 cm was cut out, and two polarizing plates in a crossed Nicol state (single transmittance 43.5%, polarization degree 99.9%) were obtained. After being sandwiched at an angle of 45 °, optical color unevenness was observed in a transmission mode using a light box with a surface illuminance of 14,000 lux (lx), and evaluated according to the following criteria. (Evaluation criteria) ⁇ ⁇ ⁇ ⁇ No color unevenness ⁇ ⁇ ⁇ ⁇ Slight color unevenness ⁇ ⁇ ⁇ ⁇ Color unevenness
  • Example 1 Manufacture of polyvinyl alcohol film
  • the polyvinyl alcohol-based resin aqueous solution is supplied to a twin-screw extruder having a vent and defoamed, and then the temperature of the aqueous solution is set to 95 ° C., and the cast drum rotating at 20 m / min from the T-type slit die discharge port
  • the film was formed by discharging and casting.
  • the obtained film was peeled off from the cast drum, and dried while bringing the front and back surfaces of the film into contact with a total of 20 metal heating rolls alternately.
  • Such metal heating rolls are arranged in the order of 90 ° C., 70 ° C., 110 ° C., and 85 ° C.
  • the obtained polyvinyl alcohol film was unwound from a roll and stretched 1.7 times in the MD direction while being swelled by being immersed in a water bath at a water temperature of 30 ° C. while being conveyed in the horizontal direction.
  • the film was stretched 1.6 times in the MD direction while being immersed and dyed in an aqueous solution of 30 g / L of iodine 0.5 g / L and 30 g / L of potassium iodide, and then boric acid 40 g / L, iodine
  • the sample was uniaxially stretched 2.1 times in the MD direction while being immersed in an aqueous solution (50 ° C.) having a composition of 30 g / L of potassium halide and cross-linking with boric acid.
  • it was washed with an aqueous potassium iodide solution and then dried at 50 ° C. for 2 minutes to obtain a polarizing film having a total draw ratio of 5.7 times. No breakage occurred during the production, and the properties of the obtained polarizing film were as shown in Table 2.
  • Example 2 a polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that heat treatment was performed by blowing hot air at 130 ° C. About the obtained polarizing film, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables 1 and 2.
  • Example 3 In Example 1, the rotational speed of the cast drum was changed to 10 m / min, the film thickness was changed to 0.06 mm, and a polyvinyl alcohol film was obtained in the same manner as in Example 1 except that heat treatment was performed by blowing hot air at 120 ° C. A polarizing film was obtained. About the obtained polarizing film, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables 1 and 2.
  • Example 4 In Example 1, the polyvinyl alcohol film and the polarizing film were changed in the same manner as in Example 1 except that the rotation speed of the cast drum was changed to 10 m / min to change the film thickness to 0.06 mm and the heat treatment temperature to 110 ° C. Got. About the obtained polarizing film, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables 1 and 2.
  • Example 1 the polyvinyl alcohol film and the polarizing film were changed in the same manner as in Example 1 except that the rotation speed of the cast drum was changed to 10 m / min to change the film thickness to 0.06 mm and the heat treatment temperature to 100 ° C. Got. About the obtained polarizing film, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables 1 and 2.
  • Example 2 a polyvinyl alcohol film was obtained in the same manner as in Example 1 except that the heat treatment temperature was 150 ° C. Production of a polarizing film was started using the polyvinyl alcohol film, but when a polarizing film having a length of 1 km was produced, breakage occurred during stretching in the boric acid crosslinking step, and the intended polarizing film was not obtained. .
  • Example 3 a polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that all metal heating roll temperatures were set to 80 ° C. About the obtained polarizing film, evaluation similar to Example 1 was performed. The evaluation results are shown in Tables 1 and 2.
  • the polyvinyl alcohol-based films of Examples 1 to 4 have a thickness D (mm) and a tension when stretched 6 times in the film flow direction (MD direction) in water at 30 ° C. (A (N / mm 2 )),
  • a (N / mm 2 ) When the tension when stretched 6 times in the film flow direction (MD direction) in water at 50 ° C. is B (N / mm 2 ), the values of D ⁇ A and D ⁇ B are both formulas (1)
  • the polyvinyl alcohol film of Comparative Example 1 has a D ⁇ B value outside the range of the formula (2), while the polyvinyl alcohol films of Comparative Examples 2 and 3 satisfy the conditions (2) and (2).
  • the value of D ⁇ A was outside the range of formula (1), and the value of D ⁇ B was also outside the range of formula (2).
  • the polarizing properties of the polarizing films obtained from the respective polyvinyl alcohol-based films are found to be superior to those of Comparative Examples 1 and 3 in Examples 1 to 4. Further, in Comparative Example 2, the polarizing film is broken by breaking. Was not obtained.
  • the value of E2 / E1 is low. In this case, it was confirmed that the degree of polarization when the polarizing film was formed decreased.
  • a polarizing film comprising a polyvinyl alcohol film obtained by the production method of the present invention is excellent in in-plane uniformity of polarization performance, and is a portable information terminal, personal computer, TV, projector, signage, electronic desk calculator, electronic timepiece.
  • Word processors electronic paper, game machines, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as automobile and machinery instruments, sunglasses, anti-glare glasses, stereoscopic glasses, wearable displays, display elements (CRT) , LCD, organic EL, electronic paper, etc.) for use in antireflection layers, optical communication equipment, medical equipment, building materials, toys and the like.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Organic Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Polymers & Plastics (AREA)
  • Medicinal Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Physics & Mathematics (AREA)
  • Manufacturing & Machinery (AREA)
  • Materials Engineering (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Mechanical Engineering (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

La présente invention concerne un film à base d'alcool polyvinylique qui est excellent en termes d'aptitude à la coloration et à l'étirage et qui, même lorsqu'il est produit sous la forme d'un film continu ayant une largeur plus élevée et une épaisseur plus faible, peut former un film polarisant qui a un degré de polarisation élevé et aucune irrégularité de polarisation. Le film à base d'alcool polyvinylique est caractérisé en ce que, lorsque l'épaisseur est exprimée par D (mm), la tension au moment auquel le film a été étiré 6 fois dans la direction machine (direction MD) dans de l'eau à 30 °C est exprimée par A (N/mm2), et la tension au moment auquel le film a été étiré 6 fois dans la direction machine (direction MD) dans de l'eau à 50 °C est exprimée par B (N/mm2), alors le film satisfait aux relations suivantes (1) et (2). Relation (1) 0,6 ≤ D × A ≤ 1,2 Relation (2) 0,2 ≤ D × B ≤ 0,4
PCT/JP2016/068598 2015-06-24 2016-06-23 Film à base d'alcool polyvinylique, procédé de production d'un film à base d'alcool polyvinylique, et film polarisant WO2016208652A1 (fr)

Priority Applications (3)

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JP2016542783A JP6883990B2 (ja) 2015-06-24 2016-06-23 ポリビニルアルコール系フィルム、ポリビニルアルコール系フィルムの製造方法、及び偏光膜
KR1020177033815A KR102475405B1 (ko) 2015-06-24 2016-06-23 폴리비닐 알코올계 필름, 폴리비닐 알코올계 필름의 제조 방법 및 편광막
CN201680029754.7A CN107614578A (zh) 2015-06-24 2016-06-23 聚乙烯醇系薄膜、聚乙烯醇系薄膜的制造方法和偏光膜

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JP2015126122 2015-06-24

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Publication number Priority date Publication date Assignee Title
WO2022138720A1 (fr) * 2020-12-23 2022-06-30 三菱ケミカル株式会社 Film d'alcool polyvinylique pour la production de film polarisant, procédé de production de film d'alcool polyvinylique pour la production de film polarisant, et film polarisant

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TWI692404B (zh) * 2015-08-18 2020-05-01 日商三菱化學股份有限公司 聚乙烯醇系薄膜及使用該聚乙烯醇系薄膜而成的偏光膜
CN110356025B (zh) * 2018-04-09 2023-03-28 日东电工株式会社 偏振片的制造方法

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JP2002236212A (ja) * 2001-02-08 2002-08-23 Nitto Denko Corp 偏光板及びそれを用いた液晶表示装置
WO2009028141A1 (fr) * 2007-08-24 2009-03-05 Kuraray Co., Ltd. Film d'alcool de polyvinyle et son procédé de production
WO2014050697A1 (fr) * 2012-09-26 2014-04-03 株式会社クラレ Film d'alcool polyvinylique et film de polarisation

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JP4229932B2 (ja) 2004-07-28 2009-02-25 日東電工株式会社 偏光フィルムの製造方法
KR101202101B1 (ko) * 2004-12-28 2012-11-15 닛폰고세이가가쿠고교 가부시키가이샤 폴리비닐알콜계 필름 및 그것을 이용한 편광막, 편광판
JP5351760B2 (ja) * 2007-08-20 2013-11-27 株式会社クラレ ポリビニルアルコール系フィルム
KR101257648B1 (ko) * 2010-07-02 2013-04-29 닛폰고세이가가쿠고교 가부시키가이샤 폴리비닐알코올계 필름, 폴리비닐알코올계 필름의 제조 방법, 편광 필름 및 편광판
WO2012132984A1 (fr) * 2011-03-29 2012-10-04 株式会社クラレ Film polymère de poly(alcool de vinyle) et procédé pour la production dudit film
JP6191197B2 (ja) 2013-03-29 2017-09-06 住友化学株式会社 偏光フィルムの製造方法

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JP2002236212A (ja) * 2001-02-08 2002-08-23 Nitto Denko Corp 偏光板及びそれを用いた液晶表示装置
WO2009028141A1 (fr) * 2007-08-24 2009-03-05 Kuraray Co., Ltd. Film d'alcool de polyvinyle et son procédé de production
WO2014050697A1 (fr) * 2012-09-26 2014-04-03 株式会社クラレ Film d'alcool polyvinylique et film de polarisation

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Publication number Priority date Publication date Assignee Title
WO2022138720A1 (fr) * 2020-12-23 2022-06-30 三菱ケミカル株式会社 Film d'alcool polyvinylique pour la production de film polarisant, procédé de production de film d'alcool polyvinylique pour la production de film polarisant, et film polarisant

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JP2020166291A (ja) 2020-10-08
TWI676638B (zh) 2019-11-11
CN107614578A (zh) 2018-01-19
KR20180022648A (ko) 2018-03-06
JP6883990B2 (ja) 2021-06-09
TW201710303A (zh) 2017-03-16
JPWO2016208652A1 (ja) 2018-04-12

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