WO2017010251A1 - Film à base de poly(alcool de vinyle) et film polarisant - Google Patents

Film à base de poly(alcool de vinyle) et film polarisant Download PDF

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Publication number
WO2017010251A1
WO2017010251A1 PCT/JP2016/068599 JP2016068599W WO2017010251A1 WO 2017010251 A1 WO2017010251 A1 WO 2017010251A1 JP 2016068599 W JP2016068599 W JP 2016068599W WO 2017010251 A1 WO2017010251 A1 WO 2017010251A1
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Prior art keywords
film
polyvinyl alcohol
polarizing film
polarizing
water
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PCT/JP2016/068599
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English (en)
Japanese (ja)
Inventor
敦子 有田
早川　誠一郎
Original Assignee
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 CN201680040993.2A priority Critical patent/CN107850716B/zh
Priority to JP2016542788A priority patent/JPWO2017010251A1/ja
Priority to KR1020187000997A priority patent/KR102475404B1/ko
Publication of WO2017010251A1 publication Critical patent/WO2017010251A1/fr

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Classifications

    • 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
    • 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
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/1333—Constructional arrangements; Manufacturing methods
    • G02F1/1335—Structural association of cells with optical devices, e.g. polarisers or reflectors
    • 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 useful as a raw film for manufacturing a polarizing film. More specifically, the present invention relates to a polyvinyl alcohol film suitable for producing a wide, long and thin polarizing film with few defects such as scratches, and a polarizing film obtained using the polyvinyl alcohol film.
  • liquid crystal display devices In recent years, the development of liquid crystal display devices has been remarkable, and they are widely used in smartphones, tablets, personal computers, liquid crystal televisions, projectors, in-vehicle panels, and the like.
  • a liquid crystal display device uses a polarizing film.
  • the polarizing film a film obtained by adsorbing and orienting iodine or a dichroic dye on a polyvinyl alcohol film is mainly used.
  • the increase in screen definition, brightness, size, and thickness there is a need for a wide, long, thin polarizing film that has fewer display defects than conventional products.
  • the polarizing film is made of, for example, a polyvinyl alcohol film swelled with water (including warm water), dyed with iodine, stretched to arrange iodine molecules, and boric acid to keep the stretched state. It is manufactured by cross-linking with a cross-linking agent and drying. Such production is performed underwater while transporting the film in the horizontal direction using a drive roll or a nip roll.
  • a cross-linking agent Such production is performed underwater while transporting the film in the horizontal direction using a drive roll or a nip roll.
  • it is important not only to reduce the defects of the polyvinyl alcohol film but also to avoid the defects that occur during the production of the polarizing film. In particular, scratches generated when the film comes into contact with the roll lowers the polarization degree and light transmittance of the polarizing film and causes polarization unevenness, and thus must be avoided.
  • a polarizing film manufacturing method that focuses on the coefficient of static friction of a roll in contact with a polyvinyl alcohol film has been proposed (see Patent Document 1). Further, the coefficient of dynamic friction with respect to the stainless steel roll is 0.03 or less, the content of the surfactant is 0.01 to 3% by weight with respect to the polyvinyl alcohol resin, and the surface roughness (Ra) is 0.05 ⁇ m.
  • the following polyvinyl alcohol film for polarizing films has been proposed (see Patent Document 2).
  • Such a phenomenon is particularly remarkable in the production of a long, wide and thin polarizing film, and further improvement has been demanded.
  • the above-mentioned rubbing scratches are often about several millimeters in length in the flow direction (MD direction) of the polarizing film, and usually those having a width of several microns or more and a depth of submicron or more have been a problem.
  • a polyvinyl alcohol film capable of obtaining a polarizing film having very few scratches under such a background, and a polarizing film having few display defects using such a polyvinyl alcohol film and having excellent polarizing performance are provided. To do.
  • the present inventors have focused on the Young's modulus of the film surface in water at 25 ° C. with respect to a polyvinyl alcohol film having a thickness of 5 to 60 ⁇ m and set the value as a specific range. As a result, it has been found that a polarizing film can be produced which is less likely to be scratched when the polarizing film is produced using the polyvinyl alcohol-based film, has few display defects, and has excellent polarizing performance.
  • the gist of the present invention is a polyvinyl alcohol film having a thickness of 5 to 60 ⁇ m, and the Young's modulus of the film surface is 15 when a nanoindentation test is performed in water at 25 ° C. using a scanning probe microscope.
  • the present invention also provides a polarizing film obtained using the polyvinyl alcohol film.
  • the polyvinyl alcohol film of the present invention can reduce scratches during the production of a polarizing film, and can produce a polarizing film having few display defects and excellent polarizing performance.
  • the polyvinyl alcohol film of the present invention is characterized in that the Young's modulus of the film surface is 15 to 40 MPa when a nanoindentation test is performed in 25 ° C. water using a scanning probe microscope.
  • the nanoindentation test in the present invention is a test for measuring a displacement amount when a minute probe (cantilever probe) is pushed into a minute region on the surface of a test piece.
  • the Young's modulus (E) of the film surface can be calculated from the relationship between the load and the amount of displacement.
  • the calculation formula is as shown in the following formula (1).
  • E (2 / ⁇ ) ⁇ (k ⁇ d / ⁇ ) ⁇ ⁇ (1- ⁇ 2 ) / a ⁇ (Where E: Young's modulus, k: spring constant, d: deflection amount of cantilever, ⁇ : indentation amount, ⁇ : Poisson's ratio, a: contact area radius)
  • Such a nanoindentation test can be performed using a commercially available scanning probe microscope, and can be performed both in water and in the air.
  • the Young's modulus of the film surface is measured in the air, but the measured value of the polyvinyl alcohol film varies greatly depending on the thickness and the temperature and humidity of the environment.
  • water by making the measurement after the surface of the polyvinyl alcohol film is sufficiently swollen with water, a relatively stable measurement value can be obtained. Considering what is performed in water, the measurement result in water can be said to be an evaluation that is more realistic.
  • the polyvinyl alcohol film is immersed in water for 2 hours or more and sufficiently swollen, and then a nanoindentation test is performed.
  • the immersion conditions are preferably 0.1 to 10 hours, more preferably 1 to 3 hours.
  • the polyvinyl alcohol film of the present invention reduces scratching scratches with the roll, but the degree of occurrence of such scratches also depends on the surface roughness of the roll used for conveyance and stretching.
  • Such a roll is generally mirror-finished so that the surface roughness Rz is 1 ⁇ m or less, but even a projection having a height of about submicron is present on the surface and damages the film. Therefore, it is necessary to measure the characteristics of the film surface layer using a small indenter and adjust the Young's modulus optimal for the production of the polarizing film. Brinell, Rockwell, Vickers, etc. that push a relatively large indenter into a relatively large area with a relatively large load is difficult to accurately evaluate, and the nanoindentation test implemented in the present invention is more effective. Is the method.
  • the polyvinyl alcohol-based film of the present invention has a Young's modulus of the film surface of 15 to 40 MPa, preferably 16 to 16 when a nanoindentation test in 25 ° C. water is performed using the scanning probe microscope described above. 35 MPa, particularly preferably 17 to 30 MPa.
  • the Young's modulus of the film surface in water at 25 ° C. is less than the lower limit value, the scratches on the roll increase and the object of the present invention cannot be achieved. And the scratches are increased and the object of the present invention cannot be achieved.
  • the special point of the present invention is that it is generally considered that the higher the Young's modulus of the film surface is, the harder it is to be scratched, but in practice, the film surface should be soft enough to ensure adhesion to the roll. It is a point that I found out. If the surface is too hard, the film simply slides on the roll, and smooth conveyance in accordance with the rotation of the roll is not performed, and the damage tends to increase.
  • a remarkable effect of the present invention is a wound self-repair function.
  • Such a self-repair function is a function in which the polymer chain of the polyvinyl alcohol resin moves to a recessed portion and is flattened.
  • the dent is deep, it is difficult to completely repair the dent, but for example, a shallow scratch having a depth of about submicron is repaired.
  • the Young's modulus of the surface of the polyvinyl alcohol film in water at 25 ° C. is less than 15 MPa, deep scratches are likely to occur, so self-healing does not occur.
  • the film surface has the Young's modulus in the specific range described above, effective self There is a tendency to develop a repair function.
  • a method for controlling the Young's modulus of the film surface in water at 25 ° C. a method for adjusting the chemical structure and molecular weight of the polyvinyl alcohol resin, a method for adjusting the components and blending amount of the polyvinyl alcohol resin aqueous solution, polyvinyl Examples thereof include a method for adjusting the film forming conditions of the alcohol film and a method for adjusting the heat treatment conditions of the polyvinyl alcohol film.
  • a method for adjusting the additive component and blending amount of the polyvinyl alcohol resin aqueous solution preferably a method for adjusting the blending amount of glycerin
  • a heat treatment condition of the polyvinyl alcohol film are adjusted.
  • the method of adjusting the heat treatment temperature is more preferable from the viewpoint of accurate control of the Young's modulus of the film surface.
  • the amount (ratio) of glycerin is 5 to 15% by weight based on the polyvinyl alcohol resin. Preferably, it is 6 to 12% by weight. If the amount of glycerin is too small, the Young's modulus of the film surface in 25 ° C water tends to increase, and if too large, the Young's modulus of the surface in 25 ° C water tends to decrease.
  • the heat treatment temperature for controlling the Young's modulus of the film surface in 25 ° C. water under the above heat treatment conditions is preferably 80 to 150 ° C., particularly preferably 80 to 140 ° C., and more preferably 90 to 140 ° C. If the heat treatment temperature is too low, the surface Young's modulus in 25 ° C water tends to decrease, and if it is too high, the Young's modulus of the film surface in 25 ° C water becomes too high, and the stretchability at the time of producing a polarizing film decreases. Tend to.
  • Examples of the heat treatment method include a method in which hot air is blown with a floating dryer, a method in which near infrared rays are irradiated with an infrared lamp, and the like.
  • the heat treatment time is usually 0.1 to 60 minutes.
  • the polyvinyl alcohol film of the present invention preferably has a Young's modulus of the film surface of 100 to 1,000 MPa when subjected to a nanoindentation test using a scanning probe microscope in air at 25 ° C. and 60% RH. Particularly preferred is 200 to 700 MPa. If the Young's modulus of the film surface in the atmosphere is too low or too high, it becomes difficult to control the Young's modulus of the film surface in water.
  • the polyvinyl alcohol film of the present invention preferably has a surface roughness Ra of 3 nm or less, particularly preferably 2 nm or less, and more preferably 1 nm or less when measured with a scanning probe microscope in water at 25 ° C. It is. If the surface roughness Ra in water is too large, scratches during the production of the polarizing film tend to increase.
  • the surface roughness Ra is a value obtained when a 10 ⁇ m square is measured in 25 ° C. water using a scanning probe microscope.
  • the polyvinyl alcohol film of the present invention is produced by forming a polyvinyl alcohol resin as a raw material.
  • 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 not to be obtained when the polyvinyl alcohol resin is used as an optical film, and if it is too large, it is difficult to stretch the polyvinyl alcohol film during the production of a polarizing film. There is.
  • 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 film of the present invention prepares a polyvinyl alcohol resin aqueous solution using the above polyvinyl alcohol resin, and discharges and casts the aqueous solution into a rotating casting mold using the polyvinyl alcohol resin aqueous solution. Then, it can be continuously produced by forming and drying the film by a casting method, and for example, it can be produced by the following steps.
  • a step of forming a film by a casting method The process of heating and drying the formed film.
  • C A step of slitting both ends of the dried film and then winding it on a roll.
  • 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.
  • 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 resin aqueous solution may be prepared 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 polyvinyl alcohol-based resin aqueous solution contains a commonly used plasticizer such as glycerin, and a surfactant composed of at least one of nonionic, anionic, and cationic. Is preferable in terms of the film-forming property of the polyvinyl alcohol film.
  • the content of the plasticizer such as glycerin and the surfactant is preferably 1 to 20% by weight, and more preferably 5 to 15% by weight with respect to the polyvinyl alcohol resin.
  • 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 of such an aqueous solution is too low, the drying load increases and the production capacity tends to decrease. If it is too high, the viscosity becomes too high and uniform dissolution tends to be difficult.
  • the obtained polyvinyl alcohol resin aqueous solution is defoamed.
  • 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 temperature of the polyvinyl alcohol resin aqueous solution at the exit of the T-type slit die is preferably 80 to 100 ° C., and particularly preferably 85 to 98 ° C. If the temperature of the aqueous polyvinyl alcohol resin solution is too low, it tends to cause poor flow, and if it is too high, it 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.
  • 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 width of the cast drum is preferably 4 m or more, particularly preferably 4.5 m or more, more preferably 5 m or more, and particularly preferably 5 to 6 m. If the width of the cast drum is too small, the productivity tends to decrease.
  • the rotational speed of such a 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 such a 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.
  • a process (B) is a process of heating and drying the formed film.
  • the film formed on the cast drum is dried by alternately bringing the front and back surfaces of the film into contact with a plurality of metal heating rolls.
  • the surface temperature of the metal heating roll is usually 40 to 150 ° C., preferably 50 to 130 ° C., particularly preferably 60 to 110 ° C. If the surface temperature is too low, drying tends to be poor. If the surface temperature is too high, drying tends to be excessive, and appearance defects such as undulation tend to be caused.
  • the metal heating roll is, for example, a roll having a diameter of 0.2 to 2 m, whose surface is hard chrome plated or mirror-finished, and is usually dried using 2 to 30 rolls, preferably 10 to 25 rolls. Is preferred.
  • Step (C) is a step in which both ends of the film are slit and wound on a roll.
  • drum-type roll rotating cast drum
  • the thickness of the polyvinyl alcohol film is required to be 5 to 60 ⁇ m from the viewpoint of thinning the polarizing film, and preferably from 5 to 30 ⁇ m from the viewpoint of further thinning. From the viewpoint of the relationship between the characteristics of the invention (Young's modulus of the film surface) and thinning, it is particularly preferably 10 to 30 ⁇ m.
  • the thickness of the polyvinyl alcohol film can be adjusted by adjusting the resin concentration in the polyvinyl alcohol resin aqueous solution, the discharge amount (discharge speed) of the polyvinyl alcohol resin aqueous solution onto the cast drum, the rotation speed of the cast drum, and the like.
  • the width of the polyvinyl alcohol film is preferably 4 m or more, more preferably 4.5 m or more from the viewpoint of increasing the area, and particularly preferably 4.5 to 6 m from the viewpoint of avoiding breakage.
  • the length of the polyvinyl alcohol film is preferably 4 km or more, more preferably 4.5 km or more from the viewpoint of increasing the area, and particularly preferably 4.5 to 50 km from the viewpoint of transport weight.
  • a roll-like polyvinyl alcohol film is obtained by winding a polyvinyl alcohol film having a width of 4 m or more and a length of 4 km or more on a roll.
  • Such a polyvinyl alcohol film has an appropriate surface Young's modulus, 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 polarization 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.
  • the polarizing film and polarizing plate obtained by the present invention have few display defects and uneven color, and are excellent in in-plane uniformity of polarization performance, such as portable information terminals, personal computers, televisions, projectors, signage, electronic desk calculators, electronic Watches, word processors, electronic paper, game consoles, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as cars 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.
  • portable information terminals personal computers, televisions, projectors, signage, electronic desk calculators, electronic Watches, word processors, electronic paper, game consoles, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as cars and machinery instruments, sunglasses, anti-glare glasses, stereoscopic glasses, wearable displays, display elements ( CRT, LCD, organic
  • ⁇ Measurement conditions (1) Young's modulus (MPa) of the film surface in an underwater nanoindentation test A 1 cm ⁇ 1 cm test piece was cut out from the obtained polyvinyl alcohol film, and the test piece was immersed in ion exchange water at 25 ° C. for 2 hours, and then a scanning probe microscope (“MFP-3D stand-alone” manufactured by ASYLUM RESEARCH) was used. Using, the Young's modulus (MPa) of the film surface in 25 degreeC water was measured. Detailed measurement conditions are as follows.
  • Measurement mode Force mode Cantilever: TR800PSA (S) (resonance frequency: 73 kHz, spring constant: 0.57 N / m) Scanning range: 1 ⁇ m ⁇ 1 ⁇ m Number of captured data: 16 x 16 Indentation speed: 1.98 ⁇ m / s Maximum pushing amount: 200nm The average value of the obtained 256 points of data was defined as the Young's modulus (MPa) of the film surface in water.
  • the preconditions for calculating the Young's modulus of the film surface are as follows.
  • Cantilever tip shape Punch (cylinder), radius 9.00 nm Poisson's ratio: 0.4
  • Measurement mode Force mode Cantilever: AC160TS (resonance frequency: 300 kHz, spring constant: 26 N / m) Scanning range: 1 ⁇ m ⁇ 1 ⁇ m Number of captured data: 16 x 16 Indentation speed: 1.98 ⁇ m / s Maximum pushing amount: 20nm The average value of the obtained 256 points of data was defined as the Young's modulus (MPa) of the film surface in the atmosphere.
  • the preconditions for calculating the Young's modulus of the film surface are as follows.
  • Cantilever tip shape Punch (cylinder), radius 9.00 nm Poisson's ratio: 0.4
  • Measurement mode Dynamic force mode (DFM) Cantilever: TR800PSA (S) (resonance frequency: 73 kHz, spring constant: 0.57 N / m) Scanning range: 10 ⁇ m ⁇ 10 ⁇ m Number of captured data: 256 x 256 Scanning speed: 0.5Hz
  • Polarization degree (%), single transmittance (%) A specimen having a length of 4 cm and a width of 4 cm was cut out from the obtained polarizing film, and the degree of polarization (%) and the single transmittance (%) were measured using an automatic polarizing film measuring device (manufactured by JASCO Corporation: VAP7070). did.
  • Example 1 Manufacture of polyvinyl alcohol film
  • 2,000 kg of a polyvinyl alcohol resin having a weight average molecular weight of 142,000 and a saponification degree of 99.8 mol%, 4,500 kg of water, and 200 kg of glycerin as a plasticizer (10 wt% with respect to the polyvinyl alcohol resin) are stirred. While raising the temperature to 140 ° C., the resin concentration was adjusted to 25% to obtain a uniformly dissolved polyvinyl alcohol-based resin aqueous solution.
  • the polyvinyl alcohol-based resin aqueous solution was supplied to a twin-screw extruder having a vent and defoamed, and the aqueous solution temperature was set to 90 ° C., and a discharge speed of 2.5 m / second was discharged from the T-type slit die discharge port to the cast drum. Cast in minutes to form a film.
  • the film was peeled off from the cast drum and dried while the front and back surfaces of the film were alternately brought into contact with a plurality of metal heating rolls.
  • the temperature of the metal heating roll was 80 to 120 ° C. Furthermore, after performing heat treatment by blowing hot air at 120 ° C.
  • the obtained polyvinyl alcohol film was unwound from a roll and stretched 1.7 times in the flow 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. Next, the film was stretched 1.6 times in the flow direction while being immersed and dyed in a 30 ° C.
  • Example 2 A polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that the amount of glycerin was 120 kg (6% by weight based on the polyvinyl alcohol resin). The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 3 A polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that the temperature of the hot air was 140 ° C. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 4 Example 1 except that the discharge speed was 1.3 m / min, the film thickness of the polyvinyl alcohol film was 30 ⁇ m, the amount of glycerin was 120 kg (6 wt% with respect to the polyvinyl alcohol resin), and the temperature of the hot air was 100 ° C. Similarly, a polyvinyl alcohol film and a polarizing film were obtained. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 5 A polyvinyl alcohol system was the same as in Example 1 except that the discharge speed was 1.3 m / min, the film thickness of the polyvinyl alcohol film was 30 ⁇ m, and the amount of glycerin was 120 kg (6 wt% with respect to the polyvinyl alcohol resin). A film and a polarizing film were obtained. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 6 Example 1 except that the discharge speed was 1.3 m / min, the film thickness of the polyvinyl alcohol film was 30 ⁇ m, the amount of glycerin was 200 kg (10 wt% with respect to the polyvinyl alcohol resin), and the hot air temperature was 140 ° C. Similarly, a polyvinyl alcohol film and a polarizing film were obtained. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 7 Example 1 except that the discharge speed was 0.8 m / min, the film thickness of the polyvinyl alcohol film was 20 ⁇ m, the amount of glycerin was 160 kg (8 wt% with respect to the polyvinyl alcohol resin), and the hot air temperature was 120 ° C. Similarly, a polyvinyl alcohol film and a polarizing film were obtained. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 1 A polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that the amount of glycerin was 160 kg (8 wt% with respect to the polyvinyl alcohol resin) and the temperature of the hot air was 150 ° C.
  • the properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • Example 2 A polyvinyl alcohol film and a polarizing film were obtained in the same manner as in Example 1 except that the discharge speed was 1.3 m / min, the film thickness of the polyvinyl alcohol film was 30 ⁇ m, and the temperature of the hot air was 100 ° C. After manufacturing the polarizing film, the dirt in each bath was visually confirmed, and shavings were confirmed. The properties of the obtained polyvinyl alcohol film and polarizing film are as shown in Table 1.
  • the Young's modulus of the film surface in water at 25 ° C. in the nanoindentation test is within the specific range of the present invention. A polarizing film with a small amount was obtained.
  • the polyvinyl alcohol films of Comparative Examples 1 and 2 have a Young's modulus outside the specific range of the present invention. Therefore, the polarizing film obtained using the films has many scratches. It can be seen that the polarizing properties of the polarizing films obtained from the respective polyvinyl alcohol-based films are better in Examples 1 to 7 than in Comparative Examples 1 and 2.
  • the polarizing film and polarizing plate obtained by the present invention have few display defects and uneven color, and are excellent in in-plane uniformity of polarization performance, such as portable information terminals, personal computers, televisions, projectors, signage, electronic desk calculators, electronic Watches, word processors, electronic paper, game consoles, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as cars 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.
  • portable information terminals personal computers, televisions, projectors, signage, electronic desk calculators, electronic Watches, word processors, electronic paper, game consoles, videos, cameras, photo albums, thermometers, audio, liquid crystal display devices such as cars and machinery instruments, sunglasses, anti-glare glasses, stereoscopic glasses, wearable displays, display elements ( CRT, LCD, organic

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  • Physics & Mathematics (AREA)
  • Chemical & Material Sciences (AREA)
  • Manufacturing & Machinery (AREA)
  • Engineering & Computer Science (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Medicinal Chemistry (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • Mathematical Physics (AREA)
  • Materials Engineering (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Manufacture Of Macromolecular Shaped Articles (AREA)
  • Polarising Elements (AREA)

Abstract

L'invention concerne un film à base de poly(alcool de vinyle) qui a une épaisseur de 5 à 60 µm et dont la surface de film, lors d'un examen dans de l'eau à 25 °C grâce à un essai de nanoindentation à l'aide d'un microscope-sonde à balayage, présente un module de Young de 15 à 40 MPa. L'utilisation de ce film à base de poly(alcool de vinyle) permet d'obtenir un film polarisant ayant très peu de défauts. En conséquence, un film polarisant présentant peu de défauts d'affichage et d'excellentes performances de polarisation est obtenu.
PCT/JP2016/068599 2015-07-16 2016-06-23 Film à base de poly(alcool de vinyle) et film polarisant WO2017010251A1 (fr)

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CN201680040993.2A CN107850716B (zh) 2015-07-16 2016-06-23 聚乙烯醇系薄膜和偏光膜
JP2016542788A JPWO2017010251A1 (ja) 2015-07-16 2016-06-23 ポリビニルアルコール系フィルム、及び偏光膜
KR1020187000997A KR102475404B1 (ko) 2015-07-16 2016-06-23 폴리비닐 알코올계 필름 및 편광막

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WO2023074639A1 (fr) * 2021-10-25 2023-05-04 株式会社クラレ Film d'alcool polyvinylique

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TWI692487B (zh) 2020-05-01
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