WO2013133063A1 - 偏光板の製造方法 - Google Patents

偏光板の製造方法 Download PDF

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Publication number
WO2013133063A1
WO2013133063A1 PCT/JP2013/054695 JP2013054695W WO2013133063A1 WO 2013133063 A1 WO2013133063 A1 WO 2013133063A1 JP 2013054695 W JP2013054695 W JP 2013054695W WO 2013133063 A1 WO2013133063 A1 WO 2013133063A1
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WIPO (PCT)
Prior art keywords
polarizing plate
film
roll
drying
treatment
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PCT/JP2013/054695
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English (en)
French (fr)
Japanese (ja)
Inventor
武藤　清
田中　孝明
大雪 山中
Original Assignee
住友化学株式会社
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Application filed by 住友化学株式会社 filed Critical 住友化学株式会社
Priority to KR1020147021138A priority Critical patent/KR101981358B1/ko
Priority to CN201380013287.5A priority patent/CN104160308B/zh
Publication of WO2013133063A1 publication Critical patent/WO2013133063A1/ja

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/04—Interconnection of layers
    • B32B7/12—Interconnection of layers using interposed adhesives or interposed materials with bonding properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B7/00—Layered products characterised by the relation between layers; Layered products characterised by the relative orientation of features between layers, or by the relative values of a measurable parameter between layers, i.e. products comprising layers having different physical, chemical or physicochemical properties; Layered products characterised by the interconnection of layers
    • B32B7/02—Physical, chemical or physicochemical properties
    • B32B7/023—Optical properties
    • 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
    • G02B5/3041—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 comprising multiple thin layers, e.g. multilayer stacks
    • G02B5/305—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 comprising multiple thin layers, e.g. multilayer stacks including organic materials, e.g. polymeric layers
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/40—Properties of the layers or laminate having particular optical properties
    • B32B2307/42—Polarizing, birefringent, filtering
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2457/00—Electrical equipment
    • B32B2457/20—Displays, e.g. liquid crystal displays, plasma displays
    • B32B2457/202—LCD, i.e. liquid crystal displays

Definitions

  • the present invention relates to a method for producing a thin polarizing plate in which a protective film is bonded to one side or both sides of a polarizing film.
  • the polarizing plate is widely used as a polarized light supplying element and a polarized light detecting element in a liquid crystal display device.
  • a polarizing plate one having a protective film bonded to both sides of a polarizing film is generally used.
  • liquid crystal display devices have been developed for mobile devices such as notebook personal computers and mobile phones. Is required to be thinner and lighter with the development of large-screen TVs. For this reason, various attempts have been made to reduce the thickness of the polarizing plate by bonding a protective film only to one surface of the polarizing film or using a thin protective film (for example, Japanese Patent Application Laid-Open No. 2007-292287 (Patent Document 1). JP, 2009-181042, A (patent document 2)).
  • the thin polarizing plate dried in a drying furnace by bonding a protective film only on one side of the polarizing film has wavy wrinkles and the like, which has a problem in appearance.
  • this problem was remarkable in a thin polarizing plate having a thickness of 105 ⁇ m or less.
  • an object of the present invention is to provide a method for producing a thin polarizing plate having a good appearance without wavy wrinkles.
  • the polarizing plate is dried by passing through a drying furnace,
  • the said widening roll is a manufacturing method of the polarizing plate as described in said (1) installed in the at least entrance part vicinity in the said drying furnace.
  • the widening roll is a pinch roll that sandwiches a side end portion of the polarizing plate, and the pinch roll is installed at both side end portions in the width direction of the conveyance path of the polarizing plate, (1) A method for producing a polarizing plate according to any one of (3) to (3).
  • the widening roll is a curved roll in which a central portion in the width direction orthogonal to the conveying direction of the polarizing plate is higher than both side end portions in the width direction (1) to (3)
  • the manufacturing method of the polarizing plate in any one of.
  • the polarizing plate when a thin polarizing plate in which a protective film is bonded to one or both sides of a polarizing film is dried, the polarizing plate is widened with a widening roll, so that the appearance is not larger than 105 ⁇ m. Can be obtained.
  • FIG. 1 is a schematic view showing a drying furnace in an embodiment of the present invention using a pinch roll 6 as a widening roll
  • FIG. 2A is a view between adjacent guide rolls 7 and 7 in the embodiment
  • FIG. 2B is a plan view for explaining the installation angle of the pinch roll 6.
  • a polarizing plate 4 is obtained by laminating and integrating a first protective film 2 a and a second protective film 2 b with a nip roll 3 on both surfaces of a polarizing film 1. Then, it is conveyed into the drying furnace 5. In the drying furnace 5, the polarizing plate 4 is conveyed by the guide roll 7 while being widened by the pinch roll 6. Thus, the dried polarizing plate 4 is obtained by passing through the drying furnace 5.
  • the polarizing film 1 is a polarizing film made of a polyvinyl alcohol resin.
  • the polyvinyl alcohol-based resin is usually obtained by saponifying a polyvinyl acetate-based resin.
  • the saponification degree of the polyvinyl alcohol-based resin is usually about 85 mol% or more, preferably about 90 mol% or more, more preferably about 99 mol% to 100 mol%.
  • Examples of the polyvinyl acetate-based resin include polyvinyl acetate, which is a homopolymer of vinyl acetate, and copolymers of vinyl acetate and other monomers copolymerizable therewith.
  • Examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, and unsaturated sulfonic acids.
  • Specific examples of the copolymer of vinyl acetate and another monomer copolymerizable therewith include ethylene-vinyl acetate copolymer.
  • the degree of polymerization of the polyvinyl alcohol resin is usually about 1000 to 10,000, preferably about 1500 to 5,000.
  • the polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal modified with aldehydes, polyvinyl acetal, polyvinyl butyral, and the like may be used.
  • an unstretched polyvinyl alcohol-based resin film having a thickness of about 20 ⁇ m to 100 ⁇ m, preferably about 30 ⁇ m to 80 ⁇ m is used as a starting material in manufacturing a polarizing film.
  • the width of the film is practically about 1500 mm to 4000 mm, but is not limited thereto.
  • This unstretched film is processed in the order of swelling treatment, dyeing treatment, boric acid treatment, and water washing treatment, then subjected to boric acid treatment or uniaxial stretching in the previous step, and finally dried to obtain a polyvinyl alcohol polarizing film. Is about 1 ⁇ m to 40 ⁇ m, for example.
  • the method for producing the polarizing film 1 is not particularly limited.
  • the unstretched polyvinyl alcohol-based resin film is uniaxially stretched in air or an inert gas, then subjected to swelling treatment, dyeing treatment with a dichroic dye, boron A method of treating in the order of acid treatment and water washing treatment, and finally drying,
  • the boric acid treatment step and / or the previous step may be performed by wet uniaxial stretching and finally drying.
  • uniaxial stretching may be performed in one step, or may be performed in two or more steps, but may be performed in a plurality of steps.
  • a stretching method a known method can be adopted, for example, a roll-to-roll stretching method in which stretching is performed with a difference in peripheral speed between two nip rolls that transport a film; a heat as described in Japanese Patent No. 2731813 Roll stretching method; tenter stretching method and the like.
  • the order of the steps is basically as described above, but there is no restriction on the number of treatment baths, treatment conditions, and the like. Moreover, you may add the process which is not described in the method of said (i) and (ii) as needed.
  • Examples of such steps include immersion treatment with an aqueous iodide solution not containing boric acid (iodide treatment) or immersion treatment with an aqueous solution containing zinc chloride not containing boric acid (zinc treatment) after boric acid treatment, etc. Is mentioned.
  • the swelling treatment step is performed for the purpose of removing foreign matter from the film surface, removing the plasticizer in the film, imparting easy dyeability in the next step, and plasticizing the film.
  • the treatment conditions are determined within a range in which these objects can be achieved and within a range in which problems such as extreme dissolution and devitrification of the polyvinyl alcohol-based resin film do not occur.
  • the film previously stretched in the gas is swelled as in the method (i) above, the film is immersed in water or an aqueous solution of, for example, about 15 ° C. to 70 ° C., preferably about 30 ° C. to 60 ° C.
  • the swelling treatment is performed.
  • the immersion time of the film is about 30 seconds to 300 seconds, preferably about 60 seconds to 240 seconds.
  • the film is placed in water or an aqueous solution of, for example, about 10 ° C. to 50 ° C., preferably about 20 ° C. to 40 ° C. It is performed by dipping.
  • the immersion time of the film is about 30 seconds to 300 seconds, preferably about 60 seconds to 240 seconds.
  • the preferred degree of swelling in the swelling treatment is 1.05 to 2.5 times.
  • the degree of swelling is defined as the mass after swelling / the mass before swelling. If the degree of swelling is small, plasticizer removal in the polyvinyl alcohol-based resin film is often insufficient, and if the degree of swelling is large, uneven dyeing tends to occur in the dyeing process performed after the swelling process. .
  • a uniaxial stretching process may be performed during the swelling process.
  • the draw ratio is preferably 3 times or less.
  • the stretch ratio is defined as the length after stretching / the length in the initial state. If the stretch ratio here is high, uneven dyeing tends to occur in the dyeing process.
  • the dyeing process is performed for the purpose of adsorbing and orienting the dichroic dye on the polyvinyl alcohol resin film.
  • the treatment conditions are determined within a range in which these objects can be achieved and within a range in which problems such as extreme dissolution and devitrification of the polyvinyl alcohol-based resin film do not occur.
  • An immersion treatment is performed for about 30 seconds to 600 seconds, preferably about 60 seconds to 300 seconds, using an aqueous solution having a concentration of 2 / about 0.1 to 10/100.
  • potassium iodide other iodides such as zinc iodide may be used alone, or other iodides and potassium iodide may be used in combination.
  • compounds other than iodide, such as boric acid, zinc chloride, cobalt chloride, etc. may coexist.
  • staining process in the case of adding a boric acid is distinguished from the following boric acid process by the point containing an iodine. Any dye containing about 0.003 parts by mass or more of iodine with respect to 100 parts by mass of water can be regarded as a dyeing treatment bath.
  • the dichroic dye / water is about 0 at a mass ratio of about 20 ° C. to 80 ° C., preferably about 30 ° C. to 70 ° C.
  • a dyeing treatment is performed by immersing in an aqueous solution having a concentration of 0.001 to 0.1 / 100 for about 30 seconds to 600 seconds, preferably about 60 seconds to 300 seconds.
  • the aqueous solution of the dichroic dye to be used may contain a dyeing assistant or the like, and may contain, for example, an inorganic salt such as sodium sulfate, a surfactant or the like.
  • the dichroic dye may be used alone, or two or more dichroic dyes may be used in combination.
  • the boric acid treatment step is generally performed by immersing a polyvinyl alcohol-based resin film dyed with a dichroic dye in an aqueous solution containing about 1 to 10 parts by mass of boric acid with respect to 100 parts by mass of water.
  • the dichroic dye is iodine
  • iodide include potassium iodide and zinc iodide.
  • compounds other than iodide such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate, etc. may coexist.
  • the boric acid treatment step is carried out for water resistance and hue adjustment (to prevent bluishness, etc.) by crosslinking.
  • a crosslinking agent such as glyoxal or glutaraldehyde can be used together with boric acid as necessary.
  • the boric acid treatment for water resistance may be referred to by names such as water resistance treatment, crosslinking treatment, and immobilization treatment.
  • boric acid treatment for hue adjustment may be referred to by a name such as complementary color treatment or re-dyeing treatment.
  • boric acid treatment for water resistance and boric acid treatment for color adjustment are not particularly distinguished, but depending on the purpose, the concentration of boric acid and iodide, the temperature of the treatment bath Is preferably changed as appropriate.
  • the unstretched polyvinyl alcohol-based resin film is subjected to a boric acid treatment after being subjected to a swelling treatment and a dyeing treatment, and the boric acid treatment is aimed at water resistance by crosslinking.
  • a boric acid treatment bath containing about 3 to 10 parts by weight of boric acid and about 1 to 20 parts by weight of iodide is used with respect to 100 parts by weight of water, usually about 50 ° C.
  • the temperature of the boric acid treatment bath is used. Is usually about 50 ° C. to 85 ° C., preferably about 55 ° C. to 80 ° C. Others may be performed in the same manner as the boric acid treatment after the above-described unstretched polyvinyl alcohol-based resin film is swollen and dyed.
  • boric acid treatment for hue adjustment may be performed.
  • the dichroic dye is iodine
  • boric acid containing about 1 to 5 parts by mass of boric acid and about 3 to 30 parts by mass of iodide with respect to 100 parts by mass of water Boric acid treatment is usually performed at a temperature of about 10 ° C. to 45 ° C. using an acid treatment bath.
  • the immersion time is usually about 3 to 300 seconds, preferably about 10 to 240 seconds.
  • Subsequent boric acid treatment for hue adjustment is usually performed at a lower boric acid concentration, a higher iodide concentration, and a lower temperature than boric acid treatment for water resistance.
  • the boric acid treatment step may consist of a single step or a plurality of steps, but is usually carried out in 2 to 5 steps.
  • the aqueous solution composition and temperature of each boric acid treatment bath used in each step may be appropriately adjusted, and may be the same or different within the above range.
  • the boric acid treatment for water resistance and the boric acid treatment for hue adjustment may be performed in a plurality of steps, respectively.
  • the boric acid treatment step washing with water is performed.
  • the water washing treatment is performed, for example, by immersing a polyvinyl alcohol-based resin film treated with boric acid for water resistance and / or hue adjustment in water, spraying water as a shower, or using both immersion and spraying.
  • the temperature of water in the water washing treatment is usually about 2 to 40 ° C., and the immersion time is preferably about 2 to 120 seconds.
  • the drying process is preferably carried out in a large number of stages by changing the tension little by little. However, the drying process is usually carried out in 2 to 5 stages due to restrictions on equipment.
  • the tension in the front stage is preferably set in the range of 600 to 1500 N / m
  • the tension in the rear stage is preferably set in the range of 300 to 1200 N / m. If the tension becomes too large, the polyvinyl alcohol-based resin film breaks more, and if it becomes too small, the generation of wrinkles increases, which is not preferable. Further, it is preferable to set the drying temperature at the former stage within the range of 30 to 90 ° C.
  • the drying treatment time can be, for example, 60 to 600 seconds, and the drying time in each stage may be the same or different. If the time is too long, it is not preferable in terms of productivity, and if the time is too short, drying is insufficient, which is not preferable.
  • a polarizing film 1 made of a polyvinyl alcohol-based resin film that is uniaxially stretched and adsorbed and oriented with a dichroic dye is obtained.
  • the thickness of the polarizing film 1 is not particularly limited as long as the total of the polarizing film 1 and the protective film bonded to both surfaces of the polarizing film 1 is 105 ⁇ m or less, and is usually about 1 to 40 ⁇ m.
  • the moisture content of the polarizing film 1 after the drying treatment is preferably 3 to 14% by mass, more preferably 3 to 10% by mass, and further preferably 3 to 8% by mass. If the moisture content exceeds 14% by mass, the polarizing film 1 tends to shrink in a dry heat environment.
  • the moisture content of the polarizing film 1 is calculated
  • a protective film is laminated
  • the first protective film 2a and the second protective film 2b may be the same or different protective films.
  • protective films include cycloolefin resin films such as norbornene resins; cellulose acetate resin films; polyester resin films such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate; polycarbonate resin films; acrylic resin films.
  • cycloolefin resin films such as norbornene resins
  • cellulose acetate resin films polyester resin films such as polyethylene terephthalate, polyethylene naphthalate, and polybutylene terephthalate
  • polycarbonate resin films such as polycarbonate resin films
  • acrylic resin films such as a polypropylene-based resin film.
  • Cycloolefin-based resins may be commercial products such as Topas (manufactured by Ticona), Arton (manufactured by JSR Corporation), ZEONOR (manufactured by Nippon Zeon Co., Ltd.), ZEONEX (manufactured by Nippon Zeon Corporation). ) And Apel (Mitsui Chemicals) can be preferably used.
  • Topas manufactured by Ticona
  • Arton manufactured by JSR Corporation
  • ZEONOR manufactured by Nippon Zeon Co., Ltd.
  • ZEONEX manufactured by Nippon Zeon Corporation
  • Apel Mitsubishi Chemicals
  • a film of a cycloolefin resin film formed in advance such as Essina (manufactured by Sekisui Chemical Co., Ltd.), SCA40 (manufactured by Sekisui Chemical Co., Ltd.), ZEONOR film (manufactured by ZEON CORPORATION) Commercial products may be used.
  • the cycloolefin resin film may be uniaxially stretched or biaxially stretched.
  • Stretching is usually performed continuously while unwinding the film roll, and the film is stretched in a heating furnace in a roll traveling direction, a direction perpendicular to the traveling direction, or both.
  • a heating furnace a range from the vicinity of the glass transition temperature of the cycloolefin resin to [glass transition temperature + 100 ° C.] is usually employed.
  • the stretching ratio is usually 1.1 to 6 times, preferably 1.1 to 3.5 times.
  • the stretching direction is arbitrary, but those that are 0 °, 45 °, and 90 ° with respect to the flow direction of the film are generally used.
  • the retardation characteristics of a film having a stretching direction of 0 ° are often uniaxial, and the retardation characteristics of films having 45 ° and 90 ° are often weakly biaxial.
  • the characteristics affect the viewing angle of the display device, but may be appropriately selected depending on the type of liquid crystal display device to be applied and the type of composite polarizing plate.
  • As the phase difference value what is usually called ⁇ / 4, ⁇ / 2, or the like is often used. In many cases, the phase difference range is 90 to 170 nm for ⁇ / 4 and 200 to 300 nm for ⁇ / 2.
  • the surface to be bonded to the polarizing film 1 is subjected to surface treatment such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, and saponification treatment. It is preferred to do so. Among these, plasma treatment and corona treatment that can be performed relatively easily are preferable.
  • the cellulose acetate-based resin that can be used for the protective film is a cellulose part or a complete acetate ester, and examples thereof include triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate.
  • a cellulose ester resin film As such a cellulose ester resin film, an appropriate commercially available product such as “KC4UY” (manufactured by Konica Minolta Opto Co., Ltd.) can be suitably used.
  • KC4UY manufactured by Konica Minolta Opto Co., Ltd.
  • a cellulose acetate-based resin film imparted with retardation characteristics is also preferably used.
  • a commercially available cellulose acetate-based resin film imparted with such retardation characteristics “WV BZ 438” (manufactured by FUJIFILM Corporation) ), “KC4FR-1” (manufactured by Konica Minolta Opto) and the like.
  • Cellulose acetate is also called acetyl cellulose or cellulose acetate.
  • the cellulose-based resin film is subjected to saponification treatment in order to enhance the adhesiveness with the polarizing film 1 particularly when the cellulose-based resin film is laminated with the polarizing film 1 using an aqueous adhesive.
  • saponification treatment a method of immersing in an aqueous solution of an alkali such as sodium hydroxide or potassium hydroxide can be employed.
  • the protective film as described above When the protective film as described above is in a roll state, the films tend to adhere to each other and easily cause blocking. Therefore, usually, the roll end is subjected to uneven processing, a ribbon is inserted into the end, A roll of a protective film is used.
  • the thickness of the protective film is not particularly limited as long as the sum of the polarizing film 1 described above and the protective film bonded to both surfaces of the polarizing film 1 is 105 ⁇ m or less, and a thin one is preferable, but if it is too thin, The strength is lowered and the processability is inferior. On the other hand, when it is too thick, problems such as a decrease in transparency, a longer curing time after bonding, and a customer request for thinning arise. Accordingly, a suitable thickness of the protective film is, for example, 1 to 50 ⁇ m, preferably 5 to 40 ⁇ m.
  • the total thickness (after drying) of the polarizing film 1 and the protective film bonded to both surfaces of the polarizing film 1 is 105 ⁇ m or less, preferably 10 ⁇ m or more and 105 ⁇ m or less, more preferably 50 ⁇ m or more and 105 ⁇ m or less. .
  • Bonding integration of the polarizing film 1 and the protective film may be performed by simultaneously bonding the polarizing film 1 and the protective film with the nip roll 3, or the protective film is bonded to one surface of the polarizing film 1 with the nip roll. Then, the protective film may be bonded to the other surface of the polarizing film 1 by a nip roll, and the polarizing film 1 and the protective film may be sequentially bonded.
  • an adhesive is applied to at least one of the polarizing film 1 and the protective film so that the polarizing film 1 and the protective film can be bonded.
  • the adhesive application device is not particularly limited, and examples thereof include a roll coating device, a gravure coating device, and a spray coating device.
  • an aqueous adhesive that is, an adhesive in which an adhesive component is dissolved in water or an adhesive in which water is dispersed; a thermosetting adhesive or the like can be used.
  • the water-based adhesive for example, a polyvinyl alcohol resin, a urethane resin or the like is used as a main component, and a composition containing an isocyanate compound, an epoxy compound, or the like can be used in order to improve adhesiveness.
  • a composition containing an isocyanate compound, an epoxy compound, or the like can be used in order to improve adhesiveness.
  • the thickness of the adhesive layer is usually 1 ⁇ m or less, and even when the cross section is observed with a normal optical microscope, the adhesive layer is practically not observed.
  • polyvinyl alcohol resin when polyvinyl alcohol resin is used as the main component of the adhesive, in addition to partially saponified polyvinyl alcohol and fully saponified polyvinyl alcohol, carboxyl group-modified polyvinyl alcohol, acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, amino group-modified A modified polyvinyl alcohol resin such as polyvinyl alcohol may be used.
  • an aqueous solution of the polyvinyl alcohol resin is used as an adhesive.
  • the concentration of the polyvinyl alcohol resin in the adhesive is usually 1 to 10 parts by weight, preferably 1 to 5 parts by weight with respect to 100 parts by weight of water.
  • the thickness of the adhesive layer after drying is usually about 0.001 to 5 ⁇ m, preferably 0.01 ⁇ m or more, preferably 2 ⁇ m or less, more preferably 1 ⁇ m or less. If the thickness of the adhesive layer becomes too large, the appearance of the polarizing plate tends to be poor.
  • ⁇ Step of drying polarizing plate 4> The polarizing plate 4 obtained as described above is conveyed into the drying furnace 5. In the drying furnace 5, the polarizing plate 4 is conveyed along the guide roll 7 while being widened by the widening roll 6, and passes through the drying furnace 5.
  • the drying oven 5 is not particularly limited, and examples thereof include a hot air drying oven, an infrared drying oven, a hot air type and an infrared drying oven.
  • the total length of the conveying path of the polarizing plate in the drying furnace 5 is usually 10 to 60 m, preferably 20 to 50 m.
  • the drying temperature in the drying furnace 5 is usually 30 ° C. to 100 ° C., more preferably 60 ° C. to 100 ° C. If the drying temperature is too high, curling is likely to occur in the polarizing plate 4, which is not preferable. On the other hand, if the drying temperature is too low, it is difficult to remove moisture when using a water-based adhesive.
  • the drying time that is, the time from when the polarizing plate 4 is carried into the drying furnace 5 to when the polarizing plate 4 passes through the drying furnace 5 is usually 50 to 1200 seconds, preferably 60 to 1000 seconds, more preferably. Is 100 to 600 seconds. If the drying time is too short, the polarizing film 1 and the protective film easily peel off due to insufficient drying, and if it exceeds 1200 seconds, it is not preferable from the viewpoint of productivity.
  • the drying furnace 5 may be composed of a plurality of drying furnaces having different drying temperatures. In such a case, the drying temperature may be appropriately adjusted according to the type of adhesive.
  • a guide roll 7 is installed to control the conveyance path of the polarizing plate 4, and a pinch roll 6 is installed along the conveyance path of the polarizing plate 4.
  • the pinch roll 6 and the guide roll 7 are both driven rollers and are driven in accordance with the movement of the polarizing plate 4 conveyed by driving a take-up roller (not shown) that winds the polarizing plate 4. It is.
  • the pinch roll 6 and the guide roll 7 are preferably a metal roll such as a stainless steel polishing roll having a low thermal conductivity, a plastic roll, a rubber roll, or the like because it directly contacts the polarizing plate 4.
  • the stainless steel polishing roll is made of SUS304, SUS316, etc., and its surface roughness is expressed as an average interval S of local peaks of the roughness curve of JIS B 0601 (surface roughness), about 0.2 to 1 Those of 0.0S are preferred.
  • the size of the pinch roll 6 is not particularly limited, and the roll diameter is preferably about 10 to 50 mm ⁇ .
  • the length of the pinch roll 6 is at least the length shown in FIGS. 2 (a) and 2 (b).
  • the length W (the length with which one pinch roll 6 sandwiches the side edges of the polarizing plate 4) is preferably about 2% to 10% with respect to the entire width of the polarizing plate 4. Since both sides of the polarizing plate 4 are affected by heat and the protective film is easily shrunk in the width direction of the conveyance path, if the length of the pinch roll 6 is in the above range, the generation of wrinkles and the like is efficient. Can be suppressed.
  • a water-based adhesive is used as the adhesive, it is effective because moisture easily escapes from both side ends of the polarizing plate 4.
  • the pinch rolls 6 are installed at both end portions of the conveyance path as shown in FIG. 2A from the viewpoint of obtaining the polarizing plate 4 without unevenness.
  • the pinch roll 6 may be tilted at an angle ⁇ in the transport direction of the polarizing plate 4 or tilted at an angle ⁇ in the direction opposite to the transport direction.
  • FIG. 2B shows a state in which the pinch roll 6 is inclined in the transport direction (indicated by an arrow).
  • the angle ⁇ is 0 to ⁇ 45 °, preferably 0 to ⁇ 30 °, preferably 0 to ⁇ 30 °, with respect to the width direction orthogonal to the longitudinal direction of the conveyance path.
  • the angle is preferably 0 to ⁇ 15 °, and particularly preferably 0 ° (provided that + is when in the transport direction of the polarizing plate 4 and ⁇ is when the direction is opposite to the transport direction of the polarizing plate 4). ).
  • FIG. 2B shows only one of the pinch rolls 6 and 6 on both sides, but the other is the same.
  • the pinch rolls 6 and 6 may be inclined in the vertical direction (vertical direction) of the conveyance path.
  • the inclination angle is 0 to ⁇ 45 °, preferably 0 to ⁇ 30 °, more preferably 0 to ⁇ 30 ° at the tip (tip located at the center of the polarizing plate 4) with respect to the rear end of the pinch roll 6. It is 15 °, and particularly preferably 0 ° (however, when the tip is above the rear end of the pinch roll 6 is +, and when it is below is ⁇ ).
  • the pinch roll 6 is preferably installed in the drying furnace 5 at least near the entrance. Since the polarizing plate 4 immediately after being transported into the drying furnace 5 is easily affected by heat and easily contracts in the width direction, the pinch roll 6 is installed at least in the vicinity of the inlet portion in the drying furnace 5 so as to be wavy. Generation of wrinkles and the like can be effectively suppressed.
  • the vicinity of the entrance in the drying furnace 5 refers to a region having a length of 1 ⁇ 4 to 3 from the entrance with respect to the entire length of the conveyance path of the polarizing plate 4 in the drying furnace 5.
  • One or more pinch rolls 6 can be installed near the entrance.
  • pinch rolls 6 and four guide rolls 7 are installed in the drying furnace 5, but the pinch roll 6 is installed in the drying furnace 5. It may be installed at 1 to 10 places, preferably 2 to 8 places. In this way, if there are a plurality of installation locations of the pinch roll 6, it is possible to suppress the polarizing plate 4 from contracting in the width direction of the transport path due to the influence of heat, so that the generation of wavy wrinkles and the like is further effective. Can be suppressed.
  • FIG. 3 is a perspective view showing another example of the widening roll preferably used in the manufacturing method of the present invention.
  • a curved roll 8 shown in FIG. 3 is used instead of the pinch roll 6 described above.
  • a metal such as stainless steel, a plastic, a rubber roll, or the like can be used.
  • a curved roll and a pinch roll may be used in combination as appropriate as the widening roll.
  • Example 1 A polyvinyl alcohol film having a thickness of 75 ⁇ m was uniaxially stretched by a dry method, and further immersed in pure water while being kept in a tension state, and then immersed in an aqueous solution of iodine / potassium iodide / water. Then, it was immersed in an aqueous solution of potassium iodide / boric acid / water, subsequently washed with pure water, and then dried to obtain a polarizing film 1 in which iodine was adsorbed and oriented on polyvinyl alcohol. The thickness of the polarizing film 1 was 28 ⁇ m.
  • polarizing film 1 On one surface of the obtained polarizing film 1, a pre-corona-treated norbornene-based resin film (“ZEONOR FILM (registered trademark)”, manufactured by Nippon Zeon Co., Ltd., thickness: 33 ⁇ , hereinafter sometimes referred to as “COP”) ), And a film made of triacetyl cellulose (“KC4UYW”, manufactured by Konica Minolta Opto Co., Ltd., thickness: 40 ⁇ m, hereinafter sometimes referred to as “TAC”) whose saponification treatment has been performed on the other surface respectively.
  • the polarizing plate 4 was obtained by pasting with the nip roll 3 through the adhesive.
  • the inside of the drying furnace 5 was passed and it dried at 70 degreeC for 220 second, and the polarizing plate 4 was obtained.
  • the total thickness of the obtained polarizing plate 4 was 101 ⁇ m, and no problem was found in the visual appearance.
  • the drying oven 5 is a hot air drying oven and has a structure shown in FIG.
  • Each pinch roll 6 has a roll diameter of 20 mm ⁇ , and is arranged at the side end of the conveyance path with an angle ⁇ of + 10 ° as shown in FIG.
  • the pinch rolls 6 and 6 were arrange
  • Examples 2 to 5> A polarizing plate was obtained in the same manner as in Example 1 except that the first protective film, the polarizing film and the second protective film shown in Table 1 were used.
  • a polarizing plate was obtained in the same manner as in Example 1 except that the first protective film, the polarizing film and the second protective film shown in Table 1 were used and a pinch roll was not used in the drying furnace.
  • Example 1 A polarizing plate was obtained in the same manner as in Example 1 except that TAC (thickness: 40 ⁇ m) was used as the first protective film.
  • Table 1 shows the total thickness of the polarizing plates obtained in Examples 1 to 5, Comparative Examples 1 to 5, and Reference Examples 1 and 2, and the results of visual appearance evaluation.
  • “1” indicates that no abnormality such as wrinkles was observed on the appearance of the polarizing plate
  • “2” indicates that abnormality such as wavy wrinkles was observed on the appearance.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • Polarising Elements (AREA)
  • Laminated Bodies (AREA)
PCT/JP2013/054695 2012-03-09 2013-02-25 偏光板の製造方法 WO2013133063A1 (ja)

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WO2017170527A1 (ja) * 2016-03-29 2017-10-05 日東電工株式会社 フレキシブル偏光膜、その製造方法および画像表示装置
JP6979839B2 (ja) * 2017-09-26 2021-12-15 住友化学株式会社 光学フィルムの製造方法及び製造装置
JP7308905B2 (ja) * 2017-09-26 2023-07-14 住友化学株式会社 光学フィルムの製造方法及び製造装置
JPWO2021044916A1 (zh) * 2019-09-05 2021-03-11
CN111113870A (zh) * 2019-12-30 2020-05-08 丁晟 一种液晶显示偏光片生产拉伸工序加工处理工艺

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JP2009069375A (ja) * 2007-09-12 2009-04-02 Sumitomo Chemical Co Ltd 偏光板の製造方法
JP5382843B2 (ja) * 2007-10-31 2014-01-08 住友化学株式会社 偏光板の製造方法
JP4762320B2 (ja) * 2009-02-20 2011-08-31 住友化学株式会社 液晶表示装置
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JP2012027459A (ja) * 2010-06-22 2012-02-09 Sumitomo Chemical Co Ltd 偏光フィルムの製造方法

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CN104160308B (zh) 2017-02-22
KR101981358B1 (ko) 2019-05-22
JP2013186367A (ja) 2013-09-19
CN104160308A (zh) 2014-11-19
TW201344258A (zh) 2013-11-01
KR20140138608A (ko) 2014-12-04
TWI561862B (en) 2016-12-11

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