WO2017104634A1 - 偏光フィルムの製造装置及び製造方法、並びに偏光フィルム - Google Patents
偏光フィルムの製造装置及び製造方法、並びに偏光フィルム Download PDFInfo
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- WO2017104634A1 WO2017104634A1 PCT/JP2016/086988 JP2016086988W WO2017104634A1 WO 2017104634 A1 WO2017104634 A1 WO 2017104634A1 JP 2016086988 W JP2016086988 W JP 2016086988W WO 2017104634 A1 WO2017104634 A1 WO 2017104634A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/18—Processes for applying liquids or other fluent materials performed by dipping
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C3/00—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material
- B05C3/02—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material the work being immersed in the liquid or other fluent material
- B05C3/12—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material the work being immersed in the liquid or other fluent material for treating work of indefinite length
- B05C3/15—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material the work being immersed in the liquid or other fluent material for treating work of indefinite length not supported on conveying means
- B05C3/152—Apparatus in which the work is brought into contact with a bulk quantity of liquid or other fluent material the work being immersed in the liquid or other fluent material for treating work of indefinite length not supported on conveying means the work passing in zig-zag fashion over rollers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
- B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
- B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
- B05C1/0808—Details thereof, e.g. surface characteristics
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C1/00—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating
- B05C1/04—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length
- B05C1/08—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line
- B05C1/086—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line a pool of coating material being formed between a roller, e.g. a dosing roller and an element cooperating therewith
- B05C1/0869—Apparatus in which liquid or other fluent material is applied to the surface of the work by contact with a member carrying the liquid or other fluent material, e.g. a porous member loaded with a liquid to be applied as a coating for applying liquid or other fluent material to work of indefinite length using a roller or other rotating member which contacts the work along a generating line a pool of coating material being formed between a roller, e.g. a dosing roller and an element cooperating therewith the work contacting the pool
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C—APPARATUS FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05C9/00—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important
- B05C9/08—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying liquid or other fluent material and performing an auxiliary operation
- B05C9/14—Apparatus or plant for applying liquid or other fluent material to surfaces by means not covered by any preceding group, or in which the means of applying the liquid or other fluent material is not important for applying liquid or other fluent material and performing an auxiliary operation the auxiliary operation involving heating or cooling
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D3/00—Pretreatment of surfaces to which liquids or other fluent materials are to be applied; After-treatment of applied coatings, e.g. intermediate treating of an applied coating preparatory to subsequent applications of liquids or other fluent materials
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D7/00—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials
- B05D7/02—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to macromolecular substances, e.g. rubber
- B05D7/04—Processes, other than flocking, specially adapted for applying liquids or other fluent materials to particular surfaces or for applying particular liquids or other fluent materials to macromolecular substances, e.g. rubber to surfaces of films or sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00634—Production of filters
- B29D11/00644—Production of filters polarizing
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D11/00—Producing optical elements, e.g. lenses or prisms
- B29D11/00865—Applying coatings; tinting; colouring
- B29D11/00894—Applying coatings; tinting; colouring colouring or tinting
- B29D11/00913—Applying coatings; tinting; colouring colouring or tinting full body; edge-to-edge
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29D—PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE
- B29D7/00—Producing flat articles, e.g. films or sheets
- B29D7/01—Films or sheets
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B65—CONVEYING; PACKING; STORING; HANDLING THIN OR FILAMENTARY MATERIAL
- B65H—HANDLING THIN OR FILAMENTARY MATERIAL, e.g. SHEETS, WEBS, CABLES
- B65H27/00—Special constructions, e.g. surface features, of feed or guide rollers for webs
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- G—PHYSICS
- G02—OPTICS
- G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02B5/00—Optical elements other than lenses
- G02B5/30—Polarising elements
Definitions
- the present invention relates to a polarizing film manufacturing apparatus and manufacturing method that can be used, for example, as a constituent member of a polarizing plate.
- the present invention also relates to a polarizing film.
- a polarizing film obtained by adsorbing and orienting a dichroic dye such as iodine or a dichroic dye on a uniaxially stretched polyvinyl alcohol resin film.
- a polarizing film is obtained by sequentially performing a dyeing process for dyeing a polyvinyl alcohol-based resin film with a dichroic dye, a crosslinking process for treating with a crosslinking agent, and a film drying process, and a uniaxial stretching process during a manufacturing process.
- Patent Document 1 Japanese Patent Laid-Open No. 2001-141926
- a polarizing film manufacturing apparatus usually has a treatment path such as a dyeing tank, a crosslinking tank, and a polyvinyl alcohol-based resin film conveyance path passing through a drying facility.
- route is supported by rolls, such as a guide roll and a nip roll which nips a film.
- a polarizing plate refers to an optical member obtained by laminating and bonding a protective layer (such as a protective film) on one or both sides of a polarizing film, typically using an adhesive.
- a protective layer such as a protective film
- liquid crystal display devices are increasingly required to have improved visibility (brightness). With this demand, backlights having higher luminance have been used for liquid crystal display devices.
- the present inventor has increased the luminance of the backlight to a certain level or more, and when the luminance is lower than this, the dot-like bright spot that was not visually recognized on the screen of the liquid crystal display device was not a problem.
- a liquid crystal panel if bubbles are mixed between the liquid crystal cell and the pressure-sensitive adhesive layer that bonds the polarizing plate to the liquid crystal cell, this bubble causes a bright spot (light loss).
- several techniques for suppressing the mixing of bubbles have been proposed.
- the bright spot newly faced by the present inventor is that bubbles mixed between the pressure-sensitive adhesive layer and the liquid crystal cell. It turned out not to be due to. And by the inventor's study, it has been clarified that the factor of the bright spot is in the polarizing film constituting the polarizing plate.
- An object of the present invention is to provide an apparatus and a method for producing a polarizing film that hardly causes the bright spot (light omission) newly faced by the present inventors as described above when applied to a liquid crystal display device. There is. Another object of the present invention is to provide a polarizing film that hardly causes the bright spot (light omission).
- the inventor of the present invention is that the above-mentioned bright spot (light loss) is caused by a specific irregularity defect (hereinafter, also referred to as “specific irregularity defect”) generated on the surface of the polyvinyl alcohol-based resin film during the manufacturing process of the polarizing film.
- specific irregularity defect also referred to as “specific irregularity defect”
- corrugated defect of a polarizing film and by extension, a bright spot (light loss) were discovered effectively by the manufacturing apparatus and manufacturing method of the polarizing film which concern on this invention shown below.
- the present invention provides the following polarizing film manufacturing apparatus and manufacturing method, and a polarizing film.
- a production apparatus for producing a polarizing film from a polyvinyl alcohol-based resin film A plurality of rolls arranged to contact the surface of the polyvinyl alcohol-based resin film, constituting a conveyance path of the polyvinyl alcohol-based resin film; A wet processing unit including one or more processing tanks disposed on the transport path and containing a processing liquid in which the polyvinyl alcohol-based resin film is immersed; A drying treatment unit disposed on the transport path for drying the polyvinyl alcohol-based resin film after the wet treatment; Including The plurality of rolls is a manufacturing apparatus including a low rotation resistance roll having a rotation resistance of 0.025 N or less.
- the wet processing unit includes, in this order, a dyeing treatment tank containing a dyeing treatment liquid containing a dichroic dye and a crosslinking treatment tank containing a crosslinking treatment liquid containing a crosslinking agent.
- the low rotation resistance roll is the manufacturing apparatus according to [2], which is disposed after the crosslinking treatment tank.
- a method for producing a polarizing film from a polyvinyl alcohol-based resin film A wet treatment step in which the polyvinyl alcohol resin film is immersed in one or more treatment liquids while being conveyed along a conveyance path constituted by a plurality of rolls arranged so as to be in contact with the surface of the polyvinyl alcohol resin film; , A drying treatment step for drying the polyvinyl alcohol-based resin film after the wet treatment while conveying the polyvinyl alcohol-based resin film along the conveyance path; Including The plurality of rolls includes a low rotation resistance roll having a rotation resistance of 0.025 N or less.
- the wet treatment step includes a step of immersing in a dyeing treatment liquid containing a dichroic dye, A step of immersing in a crosslinking treatment solution containing a crosslinking agent, in this order,
- the low rotation resistance roll is the manufacturing method according to [10], wherein the low rotation resistance roll is arranged in a conveyance path after the step of immersing in the crosslinking treatment liquid.
- the density of the concavo-convex defects on at least one surface is 20 pieces / m 2 or less
- the concavo-convex defect comprises a combination of one convex portion protruding from a polarizing film surface other than the concavo-convex defect and one concave portion that is depressed from the reference and is adjacent to the convex portion, and has a long diameter.
- the present invention it is possible to provide a polarizing film that hardly causes bright spots (light loss) due to specific irregularities on the film surface even when applied to a liquid crystal display device using a backlight with high brightness. it can.
- FIG. 1 It is a cross-sectional schematic diagram which shows an example of the polarizing film manufacturing apparatus which concerns on this invention. It is a cross-sectional schematic diagram which expands and shows the drying process part which the polarizing film manufacturing apparatus shown by FIG. 1 has. It is a flowchart which shows an example of the manufacturing method of the polarizing film which concerns on this invention.
- the present invention relates to a manufacturing apparatus and a manufacturing method for manufacturing a polarizing film from a polyvinyl alcohol-based resin film (hereinafter also referred to as “PVA-based resin film”).
- the polarizing film is produced by subjecting a PVA resin film to a series of treatments including immersion treatment (wet treatment), drying treatment and the like in a treatment tank.
- a dichroic dye is adsorbed and oriented on a stretched PVA resin film.
- FIG. 2 is an enlarged schematic cross-sectional view of a drying processing unit included in the polarizing film manufacturing apparatus shown in FIG.
- the polarizing film manufacturing apparatus shown by FIG.1 and FIG.2 is an apparatus for manufacturing the elongate polarizing film 25 continuously from the elongate PVA-type resin film 10 which is a raw material film.
- the arrow in FIG.1 and FIG.2 shows the conveyance direction of a film.
- a polarizing film 25 is obtained by performing a drying process by sequentially immersing in the processing tank 17 and the cleaning processing tank 19 and finally passing through a drying furnace 21.
- the polarizing film 25 manufactured as a long object may be wound up around the winding roll 27 sequentially.
- wet processing is performed using one or more processing tanks containing a processing solution in which a film is immersed, such as a swelling processing tank 13, a dyeing processing tank 15, a crosslinking processing tank 17, and a cleaning processing tank 19.
- the zone is referred to herein as a “wet processing unit” (wet processing unit 20 shown in FIG. 1).
- a zone in which a drying process is performed on a film after a wet process like the drying furnace 21 is referred to as a “drying processing unit” (drying processing unit 22 shown in FIGS. 1 and 2) in this specification.
- the polarizing film manufacturing apparatus has a transport path for the PVA-based resin film 10 including a wet processing unit and a drying processing unit. A series of treatments are performed by transporting the PVA-based resin film 10 along this transport path, and the polarizing film 25 is obtained.
- the transport speed of the PVA resin film 10 transported along the transport path is usually 10 to 50 m / min, and preferably 15 m / min or more from the viewpoint of production efficiency.
- a plurality of rolls that support and guide the running film (PVA resin film 10 and polarizing film 25) so that the transport path passes through the wet processing unit 20 and the drying processing unit 22.
- the plurality of rolls include a guide roll that is a free roll that supports one side of the film and / or a pair of rolls (usually drive rolls), and includes a nip roll that sandwiches or presses the film from both sides. it can.
- the manufacturing apparatus includes guide rolls 1a to 1s and nip rolls 2a to 2f.
- the plurality of rolls that define the transport path can also include a suction roll (suction roll) that is one type of drive roll.
- these rolls support the film in contact with one or both surfaces (main surfaces) of the film in the transport path.
- These rolls can be arranged at appropriate positions, such as before and after each treatment tank and drying means (drying furnace), and inside the treatment tank and drying means (drying furnace).
- the driving roll refers to a roll that can give a driving force for film conveyance to a film that is in contact with the roll, and may be a roll in which a roll driving source such as a motor is directly or indirectly connected. it can.
- the free roll is a roll that simply plays a role of supporting a traveling film and cannot give a driving force for film conveyance.
- the manufacturing method of the polarizing film which concerns on this invention is the following processes: Wet treatment step S101 in which the PVA resin film is immersed in one or more treatment liquids while being conveyed along a conveyance path constituted by a plurality of rolls arranged so as to be in contact with the surface of the PVA resin film, and the conveyance Drying process S102 which dries the PVA-type resin film after a wet process, conveying a PVA-type resin film along a path
- the wet process step S101 is a process performed in the above-described wet process unit 20, and the dry process step S102 is a process performed in the above-described dry process unit 22.
- the polarizing film manufacturing apparatus can include a stretching means (wet stretching means) for the PVA-based resin film 10, and the polarizing film manufacturing method according to the present invention includes a PVA-based resin film 10. Stretching process step (wet stretching process step).
- the PVA-based resin film 10 introduced into the wet processing unit 20 is a film made of a polyvinyl alcohol-based resin.
- a polyvinyl alcohol resin a saponified polyvinyl acetate resin can be used.
- 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, unsaturated sulfonic acids, and (meth) acrylamides having an ammonium group.
- (meth) acryl represents at least one selected from the group consisting of acryl and methacryl. The same applies to other terms with “(meta)”.
- the degree of saponification of the polyvinyl alcohol-based resin can be in the range of 80.0 to 100.0 mol%, preferably in the range of 90.0 to 100.0 mol%, more preferably 94.0. It is in the range of ⁇ 100.0 mol%, and more preferably in the range of 98.0 to 100.0 mol%.
- the degree of saponification is less than 80.0 mol%, the water resistance and heat-and-moisture resistance of the polarizing plate including the polarizing film 25 to be obtained can be lowered.
- the degree of saponification is the unit ratio (mol%) of the ratio of acetate groups (acetoxy groups: —OCOCH 3 ) contained in polyvinyl acetate resin, which is a raw material for polyvinyl alcohol resins, to hydroxyl groups by the saponification process.
- the following formula: Degree of saponification (mol%) 100 ⁇ (number of hydroxyl groups) / (number of hydroxyl groups + number of acetate groups) Defined by The saponification degree can be determined according to JIS K 6726 (1994).
- the average degree of polymerization of the polyvinyl alcohol-based resin is preferably 100 to 10,000, more preferably 1500 to 8000, and further preferably 2000 to 5000.
- the average degree of polymerization of the polyvinyl alcohol resin can also be determined according to JIS K 6726 (1994).
- JIS K 6726 (1994) When the average degree of polymerization is less than 100, it is difficult to obtain a polarizing film 25 having preferable polarization performance.
- it exceeds 10,000 the solubility in a solvent is deteriorated, and formation (film formation) of the PVA resin film 10 is difficult. Can be.
- An example of the PVA resin film 10 is an unstretched film formed by forming the polyvinyl alcohol resin.
- the film forming method is not particularly limited, and a known method such as a melt extrusion method or a solvent casting method can be employed.
- Another example of the PVA-based resin film 10 is a stretched film formed by stretching the unstretched film. This stretching is usually uniaxial stretching, preferably longitudinal uniaxial stretching.
- the longitudinal stretching refers to stretching in the machine flow direction (MD) of the film, that is, the longitudinal direction of the film. This stretching is preferably dry stretching. Dry stretching refers to stretching performed in the air, and is usually longitudinal uniaxial stretching.
- Hot roll stretching that performs longitudinal stretching below; Between rolls that perform longitudinal stretching due to the difference in peripheral speed between these two nip rolls while passing heating means (such as an oven) between two nip rolls installed at a distance. Stretching; tenter stretching; compression stretching and the like.
- the stretching temperature (the surface temperature of the hot roll, the temperature in the oven, etc.) is, for example, 80 to 150 ° C., preferably 100 to 135 ° C.
- the stretching ratio of the stretching is usually 1.1 to 8 times, preferably 2 depending on whether or not wet stretching is performed in the wet processing step S101 described later and the stretching ratio in the wet stretching. .5 to 5 times.
- the PVA-based resin film 10 can contain an additive such as a plasticizer.
- a plasticizer are polyhydric alcohols, and specific examples thereof include ethylene glycol, glycerin, propylene glycol, diethylene glycol, diglycerin, triethylene glycol, triglycerin, tetraethylene glycol, trimethylolpropane, polyethylene glycol and the like.
- the PVA-based resin film 10 can contain one or more plasticizers.
- the content of the plasticizer is usually 5 to 20 parts by weight, preferably 7 to 15 parts by weight with respect to 100 parts by weight of the polyvinyl alcohol resin constituting the PVA resin film 10.
- the thickness of the PVA-based resin film 10 introduced into the wet processing unit 20 depends on whether or not the PVA-based resin film 10 has been stretched, but is usually 10 From the viewpoint of thinning the polarizing film 25 to be obtained, it is preferably 100 ⁇ m or less, more preferably 65 ⁇ m or less, further preferably 50 ⁇ m or less, particularly preferably 35 ⁇ m or less (for example, 30 ⁇ m or less, and further 20 ⁇ m or less). is there. As the thickness of the PVA-based resin film 10, and hence the thickness of the polarizing film 25, is smaller, the specific unevenness defect tends to occur.
- a PVA-based resin film 10 having a small thickness for example, a thickness of 65 ⁇ m or less, further 50 ⁇ m or less, and even 35 ⁇ m or less
- a polarizing film 25 having a small thickness for example, a thickness of 20 ⁇ m or less, further 15 ⁇ m or less
- the present invention is particularly advantageous when manufacturing 10 ⁇ m or less).
- the wet processing unit 20 is a zone arranged on the transport path of the PVA-based resin film 10 and includes one or more processing tanks that store a processing liquid in which the PVA-based resin film 10 is immersed.
- a wet processing step S101 is performed in which the PVA resin film 10 is immersed in the one or more processing liquids while being conveyed.
- the transport path is constructed by a plurality of rolls that support and guide the traveling film, and some of the plurality of rolls are usually disposed in the wet processing unit 20.
- the wet processing unit 20 usually includes a dyeing processing tank 15 and a crosslinking processing tank 17 as the processing tank, and preferably further includes a swelling processing tank 13 and a cleaning processing tank 19. These treatment tanks are usually arranged in the order of the swelling treatment tank 13, the dyeing treatment tank 15, the crosslinking treatment tank 17, and the washing treatment tank 19 in this order from the upstream side of the conveyance path (see FIG. 1).
- FIG. 1 shows an example in which one swelling treatment tank 13, one dyeing treatment tank 15, one crosslinking treatment tank 17, and one washing treatment tank 19 are provided. If necessary, two dyeing treatment tanks 15 are provided. The above may be provided, and two or more crosslinking treatment tanks 17 may be provided. The same applies to the swelling treatment tank 13 and the washing treatment tank 19.
- the treatment liquid stored in the swelling treatment tank 13 can be, for example, water (pure water or the like), or may be an aqueous solution to which a water-soluble organic solvent such as alcohol is added.
- the treatment liquid (swelling bath) can also contain boric acid, chloride, inorganic acid, inorganic salt and the like.
- the swelling treatment is performed by immersing the PVA resin film 10 in the swelling bath.
- a swelling process is a process implemented as needed for the objectives, such as foreign substance removal of the PVA-type resin film 10, removal of a plasticizer, provision of easy dyeability, and plasticization of a film.
- the PVA resin film 10 may be subjected to a wet stretching process (usually a uniaxial stretching process).
- the draw ratio is usually 1.2 to 3 times, preferably 1.3 to 2.5 times.
- the temperature of the swelling bath is usually 10 to 70 ° C., preferably 15 to 50 ° C.
- the immersion time (residence time in the swelling bath) of the PVA-based resin film 10 is usually 10 to 600 seconds, preferably 20 to 300 seconds.
- the treatment liquid stored in the dyeing treatment tank 15 is a dyeing treatment liquid containing a dichroic dye.
- the dyeing treatment is performed by immersing the PVA resin film 10 in the dyeing treatment solution. Thereby, the dichroic dye is adsorbed on the PVA resin film 10.
- the dichroic dye can be iodine or a dichroic organic dye, preferably iodine.
- a dichroic dye may be used individually by 1 type, and may use 2 or more types together.
- an aqueous solution containing iodine and potassium iodide can be used as the dyeing solution.
- potassium iodide other iodides such as zinc iodide may be used, or potassium iodide and other iodides may be used in combination.
- compounds other than iodide for example, boric acid, zinc chloride, cobalt chloride and the like may coexist.
- boric acid is added, it is distinguished from the crosslinking treatment liquid described later in that it contains iodine.
- the iodine content in the dyeing solution is usually 0.003 to 1 part by weight per 100 parts by weight of water.
- the content of iodide such as potassium iodide in the dyeing solution is usually 0.1 to 20 parts by weight per 100 parts by weight of water.
- the temperature of the dyeing solution is usually 10 to 45 ° C., preferably 10 to 40 ° C., more preferably 20 to 35 ° C.
- the immersion time (residence time in the dyeing solution) of the PVA resin film 10 is usually 20 to 600 seconds, preferably 30 to 300 seconds.
- an aqueous solution containing the dichroic organic dye can be used for the dyeing treatment liquid.
- the content of the dichroic organic dye in the dyeing process liquid is usually, 1 ⁇ 10- 4 ⁇ 10 parts by weight per 100 parts by weight of water, preferably 1 ⁇ 10 -3 ⁇ 1 parts by weight.
- This dyeing treatment liquid may coexist with a dyeing assistant or the like, and may contain, for example, an inorganic salt such as sodium sulfate or a surfactant.
- a dichroic organic dye may be used individually by 1 type, and may use 2 or more types together.
- the temperature of the dyeing solution containing the dichroic organic dye is, for example, 20 to 80 ° C., preferably 30 to 70 ° C.
- the immersion time of the PVA resin film 10 is usually 30 to 600 seconds, preferably 60 to 300 seconds.
- the PVA-based resin film 10 used for the dyeing process has been subjected to at least a certain degree of stretching treatment (usually uniaxial stretching treatment).
- the stretching process may be performed while performing the dyeing process.
- the cumulative draw ratio up to the dyeing process is usually 1.6 to 4.5 times, preferably 1.8 to 4 times. .
- the treatment liquid accommodated in the crosslinking treatment tank 17 is a crosslinking treatment liquid containing a crosslinking agent.
- the crosslinking treatment is performed by immersing the dyed PVA resin film 10 in the crosslinking treatment solution. Thereby, water resistance, hue adjustment, etc. of the PVA-type resin film 10 by bridge
- crosslinking agent examples include boric acid, glyoxal, and glutaraldehyde, and boric acid is preferably used. Two or more crosslinking agents can be used in combination.
- the content of the crosslinking agent in the crosslinking treatment liquid is usually 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight per 100 parts by weight of water.
- the crosslinking treatment liquid preferably contains an iodide in addition to the crosslinking agent.
- the content of iodide in the crosslinking treatment liquid is usually 0.1 to 20 parts by weight, preferably 5 to 15 parts by weight, per 100 parts by weight of water.
- iodide examples include potassium iodide and zinc iodide.
- the crosslinking treatment liquid may contain a compound other than iodide, such as zinc chloride, cobalt chloride, zirconium chloride, sodium thiosulfate, potassium sulfite, sodium sulfate and the like.
- the temperature of the crosslinking treatment liquid is usually 50 to 85 ° C., preferably 50 to 70 ° C.
- the immersion time (residence time in the crosslinking treatment liquid) of the PVA-based resin film 10 is usually 10 to 600 seconds, preferably 20 to 300 seconds.
- the treatment liquid accommodated in the washing treatment tank 19 can be, for example, water (pure water or the like), or may be an aqueous solution to which a water-soluble organic solvent such as alcohol is added.
- a washing treatment is performed by immersing the PVA-based resin film 10 after the crosslinking treatment in this treatment solution (washing bath).
- the cleaning process is a process that is performed as necessary for the purpose of removing extraneous agents such as cross-linking agents and dichroic dyes attached to the PVA-based resin film 10.
- the temperature of the washing bath is, for example, 2 to 40 ° C. You may perform a extending
- the cleaning process may be a process of spraying the cleaning liquid as a shower on the PVA-based resin film 10 after the crosslinking process, or may be a combination of immersion in the cleaning bath and spraying of the cleaning liquid.
- FIG. 1 shows an example in which the PVA-based resin film 10 is subjected to a cleaning process by immersing it in water in a cleaning tank 19.
- wet stretching may be performed on the PVA-based resin film 10 in the wet processing step S101.
- the wet stretching is usually uniaxial stretching, and can be performed while performing any of swelling treatment, dyeing treatment, crosslinking treatment, and washing treatment, or during two or more treatments selected from these treatments.
- the wet stretching is preferably performed in one or more stages before or after the cross-linking process.
- the PVA-based resin film 10 subjected to the dyeing process is subjected to at least some stretching treatment. More preferably.
- the stretching ratio of the wet stretching is preferably the final cumulative stretching ratio of the polarizing film 25 (the one obtained by stretching the PVA resin film 10 subjected to the wet processing) from the viewpoint of the polarization characteristics of the polarizing film 25 to be obtained.
- the cumulative stretching ratio including this stretching is adjusted to 3 to 8 times.
- the polarizing film manufacturing apparatus includes wet stretching means for the PVA resin film 10.
- the wet stretching means is preferably stretching means for performing inter-roll stretching.
- the stretching means for performing the inter-roll stretching are the two nip rolls 2c and 2d disposed before and after the crosslinking treatment tank 17.
- two nip rolls arranged apart from each other can be used as the wet stretching means.
- the drying processing unit 22 is a zone for drying the PVA-based resin film 10 after the wet processing step S ⁇ b> 101 disposed on the downstream side of the wet processing unit 20 on the transport path of the PVA-based resin film 10. While continuing to transport the PVA-based resin film 10 after the wet processing step S101, a drying process can be performed by introducing the film into the drying processing unit 22, whereby the polarizing film 25 is obtained.
- the drying processing unit 22 includes a film drying means (heating means).
- a suitable example of the drying means is a drying furnace.
- the drying furnace is preferably capable of controlling the temperature in the furnace.
- the drying furnace is, for example, a hot air oven that can increase the temperature in the furnace by supplying hot air or the like.
- the drying process by a drying means is the process which adheres the PVA-type resin film 10 after wet processing process S101 to the 1 or 2 or more heating body which has a convex curve, and the process which heats this film using a heater. Also good.
- the heating body examples include a roll (for example, a guide roll that also serves as a heat roll) that includes a heat source (for example, a heat medium such as hot water or an infrared heater) and can increase the surface temperature.
- a heat source for example, a heat medium such as hot water or an infrared heater
- Examples of the heater include an infrared heater, a halogen heater, and a panel heater.
- FIG. 1 and FIG. 2 show an example in which the PVA resin film 10 after the wet processing step S101 is introduced into the drying furnace 21, and the film is dried while being conveyed along the guide rolls 1m to 1s in the furnace. Show.
- route of the PVA-type resin film 10 which a polarizing film manufacturing apparatus has can be arrange
- the temperature of the drying treatment (for example, the furnace temperature of the drying furnace 21, the surface temperature of the hot roll, etc.) is usually 30 to 100 ° C., preferably 50 to 90 ° C.
- the drying time is not particularly limited but is, for example, 30 to 600 seconds.
- the moisture content of the film is reduced by the drying process.
- the moisture content of the polarizing film 25 obtained through the drying treatment is usually 5 to 20% by weight, preferably 8 to 15% by weight.
- the moisture content is less than 5% by weight, the flexibility of the polarizing film 25 is excessively lowered, and the polarizing film 25 may be damaged or broken during subsequent transport or handling.
- the moisture content of the polarizing film 25 is higher than 20% by weight, the thermal stability of the polarizing film 25 tends to be lowered.
- the moisture content here is measured by the dry weight method.
- the polarizing film 25 is a film in which a dichroic dye is adsorbed and oriented on a stretched (usually uniaxially stretched) PVA resin film.
- the thickness of the polarizing film 25 is usually 2 to 40 ⁇ m. From the viewpoint of thinning the polarizing plate including the polarizing film 25, the thickness of the polarizing film 25 is preferably 20 ⁇ m or less, more preferably 15 ⁇ m or less, and even more preferably 10 ⁇ m or less. As described above, the present invention is particularly advantageous when the polarizing film 25 having a small thickness (for example, a thickness of 20 ⁇ m or less, further 15 ⁇ m or less, and further 10 ⁇ m or less) is manufactured.
- the visibility corrected single transmittance Ty of the obtained polarizing film 25 is preferably 40 to 47% and more preferably 41 to 45% in consideration of the balance with the visibility corrected polarization degree Py.
- the visibility correction polarization degree Py is preferably 99.9% or more, and more preferably 99.95% or more.
- the obtained polarizing film 25 may be wound in the form of a roll by sequentially winding it on a winding roll 27, or a polarizing plate preparation step (a protective layer (protective film or the like) is provided on one or both sides of the polarizing film 25 as it is without being wound).
- a protective layer protecting film or the like
- the step of laminating can also be used.
- Low rotation resistance roll The above-mentioned plurality of rolls arranged to contact and contact the surface of the PVA-based resin film 10 that establishes and regulates the conveyance path of the polarizing film manufacturing apparatus and has a rotation resistance of 0.025 N Including at least one low rotational resistance roll which is: Thereby, the specific uneven
- the rotational resistance of the low rotational resistance roll is preferably 0.01 N or less.
- the roll resistance of the roll is usually 0.001 N or more.
- the rotational resistance of the roll refers to the rotational resistance value measured as follows. That is, after winding a thin film on the roll, the outer end of the wound film is fixed to the spring alone, and only the spring is pulled when it is pulled at a constant speed so that the rotation speed of the roll is 100 rpm. It is a load.
- the specific unevenness defect can be suppressed by using the low rotation resistance roll because the tension of the PVA-based resin film 10 being transported when contacting the low rotation resistance roll is reduced, and the PVA in contact with the low rotation resistance roll As a result, the adhesive strength between the PVA resin film 10 is lowered, and as a result, the PVA resin film 10 that may occur when the PVA resin film 10 leaves the low rotation resistance roll will continue to adhere to the low rotation resistance roll. It is estimated that the deformation of the PVA-based resin film 10 accompanying the drag based on the adhesion force is suppressed.
- the kind of the low rotation resistance roll is not particularly limited, and may be a free roll such as a guide roll, or a drive roll such as a nip roll or a suction roll.
- a free roll such as a guide roll
- a drive roll such as a nip roll or a suction roll.
- only one of the pair of rolls constituting the nip roll may be the low rotation resistance roll, or both may be the low rotation resistance roll.
- the low rotation resistance roll is preferably a guide roll because it can enhance the effect of suppressing specific irregularities when it is a free roll having no driving force for film conveyance.
- the rotational resistance of the roll can be reduced by reducing the weight per unit volume of the roll or by using a bearing having a small friction moment.
- reducing the weight per unit volume of the roll is effective in reducing the rotational resistance of the roll.
- the weight per unit volume of the low rotational resistance roll is preferably 1500 kg / m 3 or less, more preferably 1000 kg / m 3 or less, and even more preferably 700 kg. / M 3 or less. It is possible to reduce the weight per unit volume of the roll by using a lightweight material such as carbon or aluminum for the core material of the roll (or the material of the entire roll) or by using a hollow roll.
- the weight per unit volume of the roll is usually 200 kg / m 3 or more.
- the low rotation resistance roll preferably has a surface with low wettability (a surface in contact with the PVA resin film 10 being conveyed).
- the low rotation resistance roll has a contact angle with water (to water). The contact angle is preferably 60 degrees or more, more preferably 80 degrees or more, and still more preferably 100 degrees or more. The maximum value of the contact angle with water is usually about 120 degrees. The contact angle of the surface of the low rotation resistance roll with respect to water is measured in accordance with the description in the example section described later.
- a roll having a surface with a large contact angle with water as described above can be provided with a surface layer (coating layer) made of a material with a large contact angle with water on the roll surface.
- a surface layer coating layer
- materials having a large contact angle with water include fluorine resins such as polytetrafluoroethylene; silicon atom-containing resins such as siloxane resins; and carbon materials such as carbon and diamond-like carbon (DLC).
- the number of low rotation resistance rolls is not particularly limited, and the low rotation resistance rolls may be arranged at any position on the conveyance path of the polarizing film manufacturing apparatus. Therefore, two or more low-rotation resistance rolls may be arranged in the transport path, or all the rolls in contact with the surface of the PVA-based resin film 10 to be transported may be low-rotation resistance rolls. In order to obtain the above, it is preferable to dispose a low-rotation resistance roll at least at any position on the transport path from the wet processing unit 20 (wet processing step S101) to the drying processing unit 22 (dry processing step S102).
- “From the wet treatment unit 20 (wet treatment step S101)” means, for example, when the first wet treatment is a swelling treatment, the upstream end of the swelling treatment tank 13 (at the time when the PVA-based resin film 10 is immersed in the swelling bath). Point to. “Over the drying processing unit 22 (drying process step S102)” refers to the downstream end (at the end of the drying process) of the drying processing unit 22 (drying unit).
- the present inventors have confirmed that the PVA-based resin film 10 after the crosslinking treatment tends to cause specific irregularities when it comes into contact with the roll, rather than before the crosslinking treatment. Therefore, it is preferable to arrange at least one low-rotation resistance roll in the conveyance path after the crosslinking treatment tank 17 (crosslinking treatment tank 17 or downstream thereof), and there are a plurality of rolls in the conveyance path after the crosslinking treatment tank 17. When it does, it is preferable to make all of these rolls into a low rotation resistance roll.
- the present inventor has confirmed that the PVA-based resin film 10 after the wet processing is more likely to cause specific irregularities when it comes into contact with the roll, rather than during the wet processing. Therefore, it is preferable to arrange at least one low-rotation resistance roll in the conveyance path downstream from the crosslinking treatment tank 17, and when a plurality of rolls exist in the conveyance path downstream from the crosslinking treatment tank 17, It is preferable to make all low resistance rolls.
- the specific unevenness defect is likely to occur. Therefore, it is preferable to arrange at least one low-rotation resistance roll in the transport path connecting the wet processing unit 20 and the drying processing unit 22 or the transport path in the first half of the drying processing unit 22.
- at least one low-rotation resistance roll in the transport path connecting the wet processing unit 20 and the drying processing unit 22 or the transport path in the first half of the drying processing unit 22.
- the moisture content of the above-mentioned “PVA-based resin film 10 having a moisture content lower than the moisture content immediately after finishing the wet treatment (immediately after leaving the last wet treatment tank)” is, for example, 8 to 30% by weight, Furthermore, it is 10 to 25% by weight.
- the meaning (measurement method) of the moisture content is the same as described above.
- the roll in contact with the PVA-based resin film 10 whose thickness is reduced by the wet stretching process is set to be a low rotation resistance roll rather than the thickness of the PVA-based resin film 10 at the time of being subjected to the wet processing step S101.
- the thickness of the “PVA-based resin film 10 whose thickness is reduced by the wet stretching process than the thickness of the PVA-based resin film 10 at the time of being subjected to the wet processing step S101” is, for example, 15 ⁇ m or less, Furthermore, it is 12 ⁇ m or less, and further still 10 ⁇ m or less.
- the roll which changes the conveyance direction of the PVA-type resin film 10 which touches it is a low rotation resistance roll.
- the transport direction vector of the PVA-based resin film 10 immediately before contacting the roll is A
- the transport direction vector of the PVA-based resin film 10 immediately after leaving the roll is B
- the transport direction of the PVA-based resin film 10 immediately before contacting the roll
- the angle (conveyance direction change angle) ⁇ formed by the vectors A and B when the transport direction of the PVA-based resin film 10 immediately after leaving the roll is the same without change is 0 °, and immediately before contacting the roll
- the angle ⁇ formed by the vectors A and B when the transport direction of the PVA-based resin film 10 and the transport direction of the PVA-based resin film 10 immediately after being separated from the roll are 180 °
- the angle ⁇ is The present invention is particularly advantageous when satisfying 30 to 180 °, or even 45 to 180 °.
- the specific concavo-convex defect referred to in the present specification that may occur on the surface of a polarizing film causes a bright spot (light omission) when the polarizing film is applied to a liquid crystal display device.
- This bright spot is a defect that is first recognized when the brightness of the backlight is increased to a certain level or more, and this is a new problem found for the first time by the present inventors.
- the above-mentioned “when the backlight brightness is increased to a certain level” is when the backlight brightness measured by a luminance meter is approximately 10,000 cd / m 2 or more.
- the luminance of the backlight includes a liquid crystal display including the backlight and a liquid crystal panel disposed thereon (the liquid crystal panel includes a liquid crystal cell and polarizing plates disposed on both sides thereof).
- the luminance of light emitted from the apparatus it corresponds to approximately 500 cd / m 2 or more.
- the specific irregularity defect typically has one convex part protruding from the polarizing film surface other than the irregularity defect, and one concave part adjacent to the convex part, which is depressed from the standard. And a combination.
- a convex part exists in the upstream of a film conveyance direction, and a concave part exists in the downstream.
- a plurality of such concavo-convex portions including convex portions and concave portions are randomly formed in a dot shape over substantially the entire surface of the polarizing film.
- the shape of the uneven portion is, for example, a circular shape or an elliptical shape when the polarizing film is viewed from above (when viewed from a direction perpendicular to the film surface), but may be indefinite.
- the specific unevenness defect has a major axis (maximum diameter) of about 0.5 to 5 mm (for example, 1 to 3 mm) when the polarizing film is viewed from above (when viewed from a direction perpendicular to the film surface).
- the specific irregularity defect typically has a height of the convex portion and a depth of the concave portion of about 0.05 to 0.5 ⁇ m with respect to the reference.
- the height difference (distance in the film thickness direction from the top of the convex portion to the bottom of the concave portion) in the specific irregularity defect is about 0.1 to 1 ⁇ m.
- the concavo-convex defect does not cause a bright spot and tends not to cause a problem.
- the presence of the specific unevenness defect can be confirmed by, for example, a loupe.
- the major axis and the height difference of the specific irregularity defect are measured according to the method described in the section of Examples described later.
- the present invention it is possible to suppress or prevent the occurrence of specific irregularities as described above on the surface of the polarizing film. Thereby, even when a polarizing film is applied to a liquid crystal display device using a backlight with high luminance, it is possible to effectively suppress or prevent bright spots (light loss).
- the polarizing film according to the present invention preferably has a density of specific irregularities on at least one surface thereof of 20 pieces / m 2 or less, more preferably 15 pieces / m 2 or less, and 10 pieces / m 2. More preferably, it is as follows. It can be said that the density of the specific irregularity defect on at least one surface of the polarizing film is preferably 0 piece / m 2 , but if it is 20 pieces / m 2 or less, the bright spot when viewing the screen of the liquid crystal display device Hardly affects the visibility of the screen regardless of the size of the screen. On the other hand, if the density of the specific unevenness defect exceeds 20 / m 2 , visibility is hindered depending on the size of the screen.
- the density of the specific concavo-convex defect is measured according to the method described in the Examples section described later.
- corrugation defect is recognized by one side of a polarizing film, the specific unevenness
- a polarizing plate can be obtained by forming a protective layer on one side or both sides of the polarizing film 25.
- the protective layer may be a protective film made of a thermoplastic resin, or may be a cured product layer of an active energy ray curable resin composition.
- a polarizing plate can be obtained by bonding a protective film on one or both surfaces of the polarizing film 25 via an adhesive layer.
- the thermoplastic resin constituting these protective films may be the same or different.
- the thermoplastic resin constituting the protective film is a light-transmitting thermoplastic resin, preferably an optically transparent thermoplastic resin.
- the thermoplastic resin include polyolefin resins such as chain polyolefin resins (polypropylene resins, etc.) and cyclic polyolefin resins (norbornene resins, etc.); cellulose resins such as triacetyl cellulose and diacetyl cellulose; polyethylene Polyester resins such as terephthalate and polybutylene terephthalate; polycarbonate resins; (meth) acrylic resins such as methyl methacrylate resins; polystyrene resins; polyvinyl chloride resins; acrylonitrile / butadiene / styrene resins; acrylonitrile -Styrene resin; Polyvinyl acetate resin; Polyvinylidene chloride resin; Polyamide resin; Polyacetal resin; Modified polyphenylene ether resin; Polysul
- chain polyolefin resin examples include a homopolymer of a chain olefin such as a polyethylene resin and a polypropylene resin, and a copolymer composed of two or more chain olefins. More specific examples include polypropylene resins (polypropylene resins that are homopolymers of propylene and copolymers mainly composed of propylene), polyethylene resins (polyethylene resins that are homopolymers of ethylene and ethylene mainly) A copolymer).
- Cyclic polyolefin-based resin is a general term for resins that are polymerized using cyclic olefins as polymerization units.
- Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or derivatives thereof, and hydrides thereof.
- norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.
- Cellulosic resins are those in which some or all of the hydrogen atoms in the hydroxyl groups of cellulose obtained from raw material cellulose such as cotton linter and wood pulp (hardwood pulp, conifer pulp) are substituted with acetyl groups, propionyl groups and / or butyryl groups. Further, it refers to a cellulose organic acid ester or a cellulose mixed organic acid ester. For example, cellulose acetate, propionate, butyrate, and mixed esters thereof can be used. Among these, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and cellulose acetate butyrate are preferable.
- the polyester-based resin is a resin other than the above cellulose-based resin having an ester bond, and is generally made of a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol.
- a polyvalent carboxylic acid or a derivative thereof a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate.
- a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol.
- suitable polyester-based resins include polyethylene terephthalate.
- Polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group, and is a resin having high impact resistance, heat resistance, flame retardancy, and transparency.
- the polycarbonate-based resin may be a resin called a modified polycarbonate in which the polymer skeleton is modified in order to lower the photoelastic coefficient, a copolymerized polycarbonate with improved wavelength dependency, or the like.
- (Meth) acrylic resin is a polymer containing structural units derived from (meth) acrylic monomers.
- the polymer is typically a polymer containing a methacrylic acid ester.
- it is a polymer in which the proportion of structural units derived from methacrylic acid esters is 50% by weight or more based on the total structural units.
- the (meth) acrylic resin may be a methacrylic acid ester homopolymer or a copolymer containing structural units derived from other polymerizable monomers.
- the proportion of structural units derived from other polymerizable monomers is preferably 50% by weight or less based on the total structural units.
- a methacrylic acid alkyl ester As the methacrylic acid ester that can constitute the (meth) acrylic resin, a methacrylic acid alkyl ester is preferable.
- alkyl methacrylates include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, t-butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate.
- alkyl methacrylate having 1 to 8 carbon atoms in the alkyl group such as 2-hydroxyethyl methacrylate.
- the carbon number of the alkyl group contained in the methacrylic acid alkyl ester is preferably 1 to 4.
- methacrylic acid esters may be used alone or in combination of two or more.
- Examples of the other polymerizable monomer that can constitute the (meth) acrylic resin include acrylic acid esters and other compounds having a polymerizable carbon-carbon double bond in the molecule. Other polymerizable monomers may be used alone or in combination of two or more.
- an acrylic acid alkyl ester is preferable.
- alkyl acrylate esters include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, isobutyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.
- alkyl acrylates having an alkyl group having 1 to 8 carbon atoms such as 2-hydroxyethyl acrylate.
- the number of carbon atoms of the alkyl group contained in the alkyl acrylate is preferably 1 to 4.
- acrylic acid esters may be used alone or in combination of two or more.
- the compound having a polymerizable carbon-carbon double bond in the molecule examples include vinyl compounds such as ethylene, propylene and styrene, and vinylcyan compounds such as acrylonitrile.
- vinyl compounds having a polymerizable carbon-carbon double bond in the molecule may be used alone or in combination of two or more.
- the protective film can be a film having both optical functions such as a retardation film and a brightness enhancement film.
- a retardation film provided with an arbitrary retardation value by stretching a film made of the thermoplastic resin (uniaxial stretching or biaxial stretching) or by forming a liquid crystal layer or the like on the film. It can be.
- the protective film may have a surface treatment layer (coating layer) such as a hard coat layer, an antiglare layer, an antireflection layer, an antistatic layer, or an antifouling layer, which is laminated on the surface.
- the thickness of the protective film is usually from 1 to 100 ⁇ m, but is preferably from 5 to 60 ⁇ m, more preferably from 5 to 50 ⁇ m from the viewpoints of strength, handleability, thinning of the polarizing plate, and the like.
- a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and preferably an aqueous adhesive, an active energy ray-curing agent.
- Adhesive When the protective films are bonded to both surfaces of the polarizing film 25, the adhesive for bonding these protective films may be the same type of adhesive or different types of adhesives.
- a water-based adhesive is one in which an adhesive component is dissolved in water or dispersed in water.
- the aqueous adhesive preferably used is, for example, an adhesive composition using a polyvinyl alcohol resin or a urethane resin as a main component.
- the polyvinyl alcohol-based resin can be a polyvinyl alcohol resin such as partially saponified polyvinyl alcohol or fully saponified polyvinyl alcohol, or a carboxyl group-modified polyvinyl alcohol. Further, modified polyvinyl alcohol resins such as acetoacetyl group-modified polyvinyl alcohol, methylol group-modified polyvinyl alcohol, and amino group-modified polyvinyl alcohol may be used.
- Polyvinyl alcohol resins include vinyl alcohol homopolymers obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, as well as copolymerization of vinyl acetate and other monomers copolymerizable therewith. It may be a polyvinyl alcohol copolymer obtained by saponifying the coalescence.
- An aqueous adhesive containing a polyvinyl alcohol resin as an adhesive component is usually an aqueous solution of a polyvinyl alcohol resin.
- 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.
- Adhesives composed of aqueous solutions of polyvinyl alcohol resins are used to improve adhesiveness, such as curable components such as polyhydric aldehydes, melamine compounds, zirconia compounds, zinc compounds, glyoxal, glyoxal derivatives, and water-soluble epoxy resins. It is preferable to contain a crosslinking agent.
- water-soluble epoxy resins include polyamide polyamine epoxy resins obtained by reacting polychloroalkylenes such as diethylenetriamine and triethylenetetramine with polycarboxylic acid polyamines such as adipic acid and epichlorohydrin. Can be suitably used.
- the addition amount of the curable component or the crosslinking agent is less than 1 part by weight with respect to 100 parts by weight of the polyvinyl alcohol resin, the effect of improving the adhesiveness tends to be small, and the addition amount is polyvinyl.
- the adhesive layer tends to become brittle.
- a urethane resin used as the main component of the adhesive
- a mixture of a polyester ionomer type urethane resin and a compound having a glycidyloxy group can be given.
- the polyester ionomer type urethane resin is a urethane resin having a polyester skeleton, into which a small amount of an ionic component (hydrophilic component) is introduced.
- Such an ionomer-type urethane resin is suitable as a water-based adhesive because it is emulsified directly in water without using an emulsifier to form an emulsion.
- the active energy ray-curable adhesive is an adhesive that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
- active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays.
- the adhesive layer of the polarizing plate is a cured product layer of the adhesive.
- the active energy ray curable adhesive can be an adhesive containing an epoxy compound that is cured by cationic polymerization as a curable component, and preferably an ultraviolet curable adhesive containing such an epoxy compound as a curable component. It is an agent.
- the epoxy compound here means a compound having an average of 1 or more, preferably 2 or more epoxy groups in the molecule.
- the epoxy compound may be used alone or in combination of two or more.
- the active energy ray-curable adhesive can contain a radically polymerizable (meth) acrylic compound as a curable component, instead of or together with the epoxy compound.
- the (meth) acrylic compound is a (meth) acrylate monomer having at least one (meth) acryloyloxy group in the molecule; obtained by reacting two or more functional group-containing compounds, and at least two in the molecule.
- (meth) acryloyloxy group-containing compounds such as (meth) acrylate oligomers having (meth) acryloyloxy groups.
- the active energy ray-curable adhesive contains an epoxy compound that is cured by cationic polymerization as a curable component, it preferably contains a photocationic polymerization initiator.
- the photocationic polymerization initiator include aromatic diazonium salts; onium salts such as aromatic iodonium salts and aromatic sulfonium salts; iron-allene complexes.
- the active energy ray-curable adhesive contains a radical polymerizable curable component such as a (meth) acrylic compound, it is preferable to contain a photo radical polymerization initiator.
- photo radical polymerization initiator examples include acetophenone initiator, benzophenone initiator, benzoin ether initiator, thioxanthone initiator, xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone and the like.
- the surface of the polarizing film and / or protective film bonding surface Prior to bonding the protective film to the polarizing film, the surface of the polarizing film and / or protective film bonding surface, such as plasma treatment, corona treatment, ultraviolet irradiation treatment, flame (flame) treatment, saponification treatment, etc. Processing may be performed. By this surface activation treatment, the adhesion between the polarizing film and the protective film can be enhanced.
- the specific concavo-convex defect is based on the polarizing film surface other than the concavo-convex defect, and one convex portion that protrudes therefrom, and one concave portion that is depressed from the reference and is adjacent to the convex portion.
- the polarizing plate for inspection and the polarizing film sample were arranged so that the transmission axis of the polarizing film contained in the polarizing plate for inspection and the transmission axis of the polarizing film sample were orthogonal to each other.
- the backlight was turned on, and the presence or absence of dot-like bright spots (light loss) on the surface of the sample was visually confirmed from the polarizing film sample side.
- the density number of bright spots per unit area, unit: pieces / m 2
- the results are shown in Table 1.
- Example 1 A long PVA-based resin using the same polarizing film manufacturing apparatus as in FIGS. 1 and 2 except that the drying processing section includes a total of 15 guide rolls (free rolls) (both are in contact with the film surface).
- a long polarizing film 25 was continuously produced from the film 10.
- a polarizing plate was produced using the obtained polarizing film 25. Specifically, it is as follows.
- PVA resin film 10 The following PVA resin film a was prepared as the PVA resin film 10.
- This PVA-based resin film a is obtained by uniaxially stretching a polyvinyl alcohol film having a thickness of 30 ⁇ m in a dry manner by a factor of 4.1.
- the saponification degree of the polyvinyl alcohol constituting the film is 99.9 mol% or more, and the average polymerization degree Is 2400 and contains 10 parts by weight of a plasticizer with respect to 100 parts by weight of polyvinyl alcohol constituting the film.
- Example 1 among the guide rolls constructing the film transport path of the polarizing film manufacturing apparatus, the guide rolls (of the 15 guide rolls) constructing the transport path of the first half of the drying furnace 21. Eight upstream) were all low-rotation resistance rolls. The following low rotation resistance roll I was used for these low rotation resistance rolls. The following guide rolls II were used as guide rolls (seven on the downstream side) other than the guide rolls that construct the transport path of the first half of the drying furnace 21. The following guide roll II was also used for all the guide rolls in the wet processing section.
- the obtained polarizing film 25 was evaluated for specific irregularity defects and bright spots (light loss) by the above-described method. The results are shown in Table 1.
- the first protective film [TAC film “KC2UAW” manufactured by Konica Minolta Opto Co., Ltd., thickness: 25 ⁇ m]
- the second protective film [Product name “FEKB015D3”, thickness: 15 ⁇ m, which is a cyclic polyolefin-based resin film manufactured by JSR Corporation] is continuously conveyed, between the polarizing film 25 and the first protective film, and between the polarizing film 25 and the second film.
- the laminated film is made of the first protective film / aqueous adhesive layer / polarizing film 25 / aqueous adhesive layer / second protective film by passing between the bonding rolls. .
- polyvinyl alcohol powder [trade name “Gosefimer” manufactured by Nippon Synthetic Chemical Industry Co., Ltd., average polymerization degree 1100] was dissolved in hot water at 95 ° C., and the concentration was 3%.
- the obtained laminated film was conveyed, passed through a hot air dryer, and heat-treated at 80 ° C. for 300 seconds to dry the aqueous adhesive layer to obtain a polarizing plate.
- Example 2 A polarizing film 25 (thickness 12 ⁇ m) was produced in the same manner as in Example 1 except that the following low rotation resistance roll III was used, and then a polarizing plate was produced. Table 1 shows the evaluation results of specific irregularity defects and bright spots (light loss).
- Example 3 In addition to all the guide rolls constructing the transport path in the first half of the drying furnace 21, all the guide rolls constructing the transport path connecting the cleaning treatment tank 19 and the drying furnace 21 are connected to the low rotation resistance roll I.
- a polarizing film 25 (thickness 12 ⁇ m) was prepared in the same manner as in Example 1 except that the polarizing plate was prepared. Table 1 shows the evaluation results of specific irregularity defects and bright spots (light loss).
- a polarizing film 25 was obtained in the same manner as in Examples 1 to 3, except that a PVA resin film b obtained by uniaxially stretching a polyvinyl alcohol film having a thickness of 20 ⁇ m by dry drying was used. (Thickness 7 ⁇ m) was prepared, and then a polarizing plate was prepared. Table 1 shows the evaluation results of specific irregularity defects and bright spots (light loss).
- polarizing film 25 (thickness: 7 ⁇ m) was used in the same manner as in Comparative Example 1 except that a PVA-based resin film b obtained by uniaxially stretching a polyvinyl alcohol film having a thickness of 20 ⁇ m by dry drying was used as the PVA-based resin film 10. ), And then a polarizing plate.
- Table 1 shows the evaluation results of specific irregularity defects and bright spots (light loss).
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Abstract
Description
前記ポリビニルアルコール系樹脂フィルムの搬送経路を構成し、前記ポリビニルアルコール系樹脂フィルムの表面に接するように配置される複数のロールと、
前記搬送経路上に配置され、前記ポリビニルアルコール系樹脂フィルムが浸漬される処理液を収容する1以上の処理槽を含む湿式処理部と、
前記搬送経路上に配置され、湿式処理後のポリビニルアルコール系樹脂フィルムを乾燥させるための乾燥処理部と、
を含み、
前記複数のロールは、回転抵抗が0.025N以下である低回転抵抗ロールを含む、製造装置。
前記低回転抵抗ロールは、前記架橋処理槽以降に配置される、[2]に記載の製造装置。
前記ポリビニルアルコール系樹脂フィルムの表面に接するように配置される複数のロールによって構成される搬送経路に沿って前記ポリビニルアルコール系樹脂フィルムを搬送させながら、1以上の処理液に浸漬させる湿式処理工程と、
前記搬送経路に沿って前記ポリビニルアルコール系樹脂フィルムを搬送させながら、湿式処理後のポリビニルアルコール系樹脂フィルムを乾燥させる乾燥処理工程と、
を含み、
前記複数のロールは、回転抵抗が0.025N以下である低回転抵抗ロールを含む、製造方法。
架橋剤を含有する架橋処理液に浸漬させる工程と、をこの順に含み、
前記低回転抵抗ロールは、前記架橋処理液に浸漬させる工程以降の搬送経路に配置される、[10]に記載の製造方法。
少なくとも一方の面における凹凸欠陥の密度が20個/m2以下であり、
前記凹凸欠陥は、前記凹凸欠陥以外の偏光フィルム面を基準にそれより突出している1つの凸部と、前記基準より陥没しており前記凸部に隣接する1つの凹部との組み合わせからなり、長径が0.5~5mmの範囲内である、偏光フィルム。
本発明は、ポリビニルアルコール系樹脂フィルム(以下、「PVA系樹脂フィルム」ともいう。)から偏光フィルムを製造するための製造装置及び製造方法に関する。偏光フィルムは、PVA系樹脂フィルムに対し、処理槽への浸漬処理(湿式処理)、乾燥処理等を含む一連の処理を施して製造される。偏光フィルムは、延伸されたPVA系樹脂フィルムに二色性色素が吸着配向しているものである。
PVA系樹脂フィルムの表面に接するように配置される複数のロールによって構成される搬送経路に沿ってPVA系樹脂フィルムを搬送させながら、1以上の処理液に浸漬させる湿式処理工程S101、及び
上記搬送経路に沿ってPVA系樹脂フィルムを搬送させながら、湿式処理後のPVA系樹脂フィルムを乾燥させる乾燥処理工程S102
を含む。湿式処理工程S101は上述の湿式処理部20で行われる処理であり、乾燥処理工程S102は上述の乾燥処理部22で行われる処理である。
湿式処理部20に導入される(湿式処理工程S101に供される)PVA系樹脂フィルム10は、ポリビニルアルコール系樹脂で構成されるフィルムである。ポリビニルアルコール系樹脂としては、ポリ酢酸ビニル系樹脂をケン化したものを用いることができる。ポリ酢酸ビニル系樹脂としては、酢酸ビニルの単独重合体であるポリ酢酸ビニルのほか、酢酸ビニルとこれに共重合可能な他の単量体との共重合体が例示される。酢酸ビニルに共重合可能な他の単量体としては、例えば、不飽和カルボン酸類、オレフィン類、ビニルエーテル類、不飽和スルホン酸類、アンモニウム基を有する(メタ)アクリルアミド類等が挙げられる。なお、「(メタ)アクリル」とは、アクリル及びメタクリルからなる群より選ばれる少なくとも1種を表す。その他の「(メタ)」を付した用語においても同様である。
ケン化度(モル%)=100×(水酸基の数)/(水酸基の数+酢酸基の数)
で定義される。ケン化度は、JIS K 6726(1994)に準拠して求めることができる。
湿式処理部20は、PVA系樹脂フィルム10の搬送経路上に配置されるゾーンであり、PVA系樹脂フィルム10が浸漬される処理液を収容する1以上の処理槽を含む。この湿式処理部20において、PVA系樹脂フィルム10を搬送させながら上記1以上の処理液に浸漬させる湿式処理工程S101が実施される。上述のように搬送経路は、走行中のフィルムを支持・案内する複数のロールによって構築されており、これらの複数のロールの一部は通常、湿式処理部20内に配置されている。
乾燥処理部22は、PVA系樹脂フィルム10の搬送経路上であって湿式処理部20の下流側に配置される、湿式処理工程S101後のPVA系樹脂フィルム10を乾燥させるためのゾーンである。湿式処理工程S101後のPVA系樹脂フィルム10を引き続き搬送させながら、乾燥処理部22に当該フィルムを導入することによって乾燥処理を施すことができ、これにより偏光フィルム25が得られる。
偏光フィルム製造装置の搬送経路を構築・規定し、搬送されるPVA系樹脂フィルム10の表面に接するように配置される上述の複数のロールは、回転抵抗が0.025N以下である少なくとも1つの低回転抵抗ロールを含む。これにより、偏光フィルム25の表面に生じ得る特定凹凸欠陥を抑制することができる。特定凹凸欠陥をより効果的に抑制する観点から、低回転抵抗ロールの回転抵抗は、0.01N以下であることが好ましい。当該ロールの回転抵抗は、通常0.001N以上である。
偏光フィルムの表面に生じ得る本明細書でいう特定凹凸欠陥は、該偏光フィルムを液晶表示装置に適用したときに輝点(光抜け)を生じさせる。この輝点は、バックライトの輝度をある程度以上まで高くしたときに初めて視認されるようになる欠陥であり、この点は本発明者により初めて見出された新たな課題である。上述の「バックライトの輝度をある程度以上まで高くしたとき」とは、輝度計で測定したバックライトの輝度がおよそ10,000cd/m2以上のときである。このバックライトの輝度は、当該バックライトと、その上に配置される液晶パネル(液晶パネルは、液晶セルとその両面に配置される偏光板とを備える。)とを含んで構成される液晶表示装置から出射される光の輝度でいえば、およそ500cd/m2以上に相当する。
偏光フィルム25の片面又は両面に保護層を形成することにより偏光板を得ることができる。保護層は、熱可塑性樹脂からなる保護フィルムであることができる他、活性エネルギー線硬化性樹脂組成物の硬化物層であってもよい。保護フィルムを用いる場合、偏光フィルム25の片面又は両面に接着剤層を介して保護フィルムを貼合することにより偏光板を得ることができる。偏光フィルム25の両面に保護フィルムが貼合される場合においてこれらの保護フィルムを構成する熱可塑性樹脂は、同種であってもよいし異種であってもよい。
(株)ニコン製のデジタルマイクロメーター「MH-15M」を用いて測定した。
水分率の異なる複数のポリビニルアルコールフィルム試料を用いて、乾燥重量法による水分率と、赤外線吸収式の水分率計((株)チノー製の「IRMA1100」)の測定値との相関を示す検量線(換算式)を作成した。上記水分率計を用いて測定値を得、これを上記検量線(換算式)に代入し乾燥重量法による水分率〔重量%〕に換算して、これをフィルムの水分率とした。乾燥重量法による水分率は、105℃で120分間熱処理したときのポリビニルアルコールフィルム試料の重量をW1、熱処理前のポリビニルアルコールフィルム試料の重量をW0とするとき、下記式:
乾燥重量法による水分率〔重量%〕={(W0-W1)÷W0}×100
に従って求めた。上記検量線は、測定対象のフィルムの厚みが異なるごとに作成した。
得られた偏光フィルムの片面(一方の面に特定凹凸欠陥が認められる場合には通常、他方の面にも同様の位置に特定凹凸欠陥が形成されている。)をルーペで観察し、特定凹凸欠陥の有無を確認した。上述のように特定凹凸欠陥は、当該凹凸欠陥以外の偏光フィルム面を基準に、それより突出している1つの凸部と、上記基準より陥没しており、該凸部に隣接する1つの凹部との組み合わせからなる。特定凹凸欠陥が存在する場合には、(株)菱化システム製の白色干渉計「VertScan」を用いて平均的な特定凹凸欠陥の長径(平均長径)、及び平均的な特定凹凸欠陥の高低差(平均高低差;凸部の頂部から凹部の底部までのフィルム厚み方向平均距離)を測定した(下記(4)参照)。また、得られた偏光フィルムから透過軸方向200mm×吸収軸方向300mmのサンプルを、ランダムな領域から3枚切り出し、それぞれについてルーペで観察して特定凹凸欠陥の個数を計測することにより、特定凹凸欠陥の密度(偏光フィルムの単位面積あたりの特定凹凸欠陥の数、単位:個/m2)を求めた。具体的には、特定凹凸欠陥の密度の算出は、下記式:
特定凹凸欠陥の密度(個/m2)=(3枚のサンプルにおける特定凹凸欠陥の合計個数)/(3枚のサンプルの合計面積)
に従った。結果を表1に示す。なお、以上の特定凹凸欠陥の確認は、得られた偏光フィルムの片面についてのみ行ったが、下記の実施例及び比較例の間で、特定凹凸欠陥の確認は偏光フィルムの同じ面について行った。
測定には、(株)菱化システム製の白色干渉計「VertScan」を用いた。長径(最大径)とは、特定凹凸欠陥を上からみたとき(フィルム面に対して垂直な方向からみたとき)の凸部の外側端から凹部の外側端までの距離のうち、最も長い距離をいう。特定凹凸欠陥を任意に10個選択し、これらの長径の平均値を「平均長径」とした。また、上記10個の特定凹凸欠陥について高低差を測定し、これらの平均値を「平均高低差」とした。結果を表1に示す。なお、実施例及び比較例において、測定した個々の特定凹凸欠陥の長径は0.5~5mmの範囲であり、高低差は0.1~1μmの範囲内であった。
得られた偏光フィルムから透過軸方向200mm×吸収軸方向300mmのサンプルを、ランダムな領域から3枚切り出し、それぞれについて輝点(光抜け)の評価を実施した。具体的には、暗室内において、輝度が20,000cd/m2((株)トプコンテクノハウス製の輝度計「BM-5A」を用いて測定。)であるバックライト上に、検査用の偏光板を配置し、さらにその上に上記偏光フィルムサンプルを配置した。この際、検査用の偏光板に含まれる偏光フィルムの透過軸と偏光フィルムサンプルの透過軸とが直交するように検査用の偏光板及び偏光フィルムサンプルを配置した。次いで、バックライトを点灯させて、偏光フィルムサンプル側から、当該サンプルの表面におけるドット状の輝点(光抜け)の有無を目視で確認した。輝点が認められる場合にはその個数を計測し、その密度(単位面積あたりの輝点の数、単位:個/m2)を求めた。具体的には、輝点の密度の算出は、下記式:
輝点の密度(個/m2)=(3枚のサンプルにおける輝点の合計個数)/(3枚のサンプルの合計面積)
に従った。結果を表1に示す。
(A)バックライトと検査用の偏光板との間に平均透過率50%のNDフィルタをさらに配置する(この場合、バックライトの実質的な輝度は、10,000cd/m2となる。)。
(B)バックライトと検査用の偏光板との間に平均透過率3%のNDフィルタをさらに配置する(この場合、バックライトの実質的な輝度は、600cd/m2となる。)。
積分球付き吸光光度計(日本分光(株)製の「V7100」)を用い、得られた透過率、偏光度に対してJIS Z 8701の2度視野(C光源)により視感度補正を行い、視感度補正単体透過率Ty及び視感度補正偏光度Pyを測定した。
ロールに薄いフィルム(厚み25μmのポリエチレンテレフタレートフィルム)を巻き付けた後、巻き付けたフィルムの外側の端部をバネばかりに固定し、バネばかりをロールの回転数が100rpmとなるように一定速度で引いた際のバネばかりにかかる荷重を測定し、これをガイドロールの回転抵抗とした。
接触角計(協和界面科学社製の全自動接触角計「DM-701」)を用いて、液滴法により、温度23℃、相対湿度50%の条件下で測定した。
乾燥処理部が合計15個のガイドロール(フリーロール)を含む(いずれもフィルム表面に接する。)こと以外は図1及び図2と同様の偏光フィルム製造装置を用いて、長尺のPVA系樹脂フィルム10から長尺の偏光フィルム25を連続製造した。次いで、得られた偏光フィルム25を用いて偏光板を作製した。具体的には次のとおりである。
PVA系樹脂フィルム10として次のPVA系樹脂フィルムaを用意した。このPVA系樹脂フィルムaは、厚み30μmのポリビニルアルコールフィルムを乾式で4.1倍に一軸延伸したものであり、フィルムを構成するポリビニルアルコールのケン化度は99.9モル%以上、平均重合度は2400であり、フィルムを構成するポリビニルアルコール100重量部に対して10重量部の可塑剤を含有している。
PVA系樹脂フィルムaを巻出ロール11から巻き出しながら、張力をかけて緊張状態を保ったまま連続的に搬送し、40℃の純水を収容する膨潤処理槽13に滞留時間60秒で浸漬してPVA系樹脂フィルムaを十分に膨潤させた(膨潤処理工程)。膨潤処理槽13から引き出したフィルムを、ヨウ素/ヨウ化カリウム/水が重量比で0.1/6/100である30℃の染色処理液を収容する染色処理槽15に滞留時間60秒で浸漬しながら、その間に一軸延伸(浴中でのロール間延伸)を行った(染色処理工程)。染色処理槽15から引き出したフィルムを、ヨウ化カリウム/ホウ酸/水が重量比で15/5.5/100である68℃の架橋処理液を収容する架橋処理槽17に滞留時間130秒で浸漬しながら、その間に一軸延伸(浴中でのロール間延伸)を行った(架橋処理工程)。架橋処理槽17から引き出したフィルムを、20℃の純水を収容する洗浄処理槽19に滞留時間3秒で浸漬して洗浄を行った(洗浄処理工程)。PVA系樹脂フィルムaを基準とする累積延伸倍率は、4.5倍であった。
引き続き、洗浄処理槽19から引き出したフィルムを連続的に搬送しながら、熱風オーブンである乾燥炉21に導入し、滞留時間90秒、温度60℃の乾燥処理を行って、偏光フィルム25を得た。得られた偏光フィルム25の厚みは12μm、視感度補正単体透過率Tyは42.5%、視感度補正偏光度Pyは99.993%、水分率は10重量%であった。得られた偏光フィルム25について特定凹凸欠陥の確認を行った。結果を表1に示す。なお、最初の低回転抵抗ロールに接するときのフィルムの厚みは、偏光フィルム25の厚みと実質的に同じである。
・構成:芯材にカーボンを用い、表面にフッ素系樹脂層がコーティングされたガイドロール、
・回転抵抗:0.008N、
・単位体積あたりの重量:640kg/m3、
・表面の対水接触角:95度、
・各低回転抵抗ロールにおけるフィルムの角度α(搬送方向変化角度):90°又は180°(各実施例及び比較例に共通)。
・構成:芯材にSUS304を用い、表面にクロムめっきが施されたガイドロール、
・回転抵抗:0.03N、
・単位体積あたりの重量:1600kg/m3、
・表面の対水接触角:75度。
得られた偏光フィルム25を連続的に搬送するとともに、第1保護フィルム〔コニカミノルタオプト(株)製のTACフィルム「KC2UAW」、厚み:25μm〕、及び第2保護フィルム〔JSR(株)製の環状ポリオレフィン系樹脂フィルムである商品名「FEKB015D3」、厚み:15μm〕を連続的に搬送し、偏光フィルム25と第1保護フィルムとの間、及び偏光フィルム25と第2保護フィルムとの間に水系接着剤を注入しながら、貼合ロール間に通して第1保護フィルム/水系接着剤層/偏光フィルム25/水系接着剤層/第2保護フィルムからなる積層フィルムとした。
次の低回転抵抗ロールIIIを使用したこと以外は実施例1と同様にして偏光フィルム25(厚み12μm)を作製し、次いで偏光板を作製した。特定凹凸欠陥及び輝点(光抜け)の評価結果を表1に示す。
・構成:芯材にカーボンを用い、表面にダイヤモンドライクカーボン層がコーティングされたガイドロール、
・回転抵抗:0.008N、
・単位体積あたりの重量:640kg/m3、
・表面の対水接触角:105度。
乾燥炉21の前半の搬送経路を構築しているすべてのガイドロールに加えて、洗浄処理槽19と乾燥炉21とを接続する搬送経路を構築しているすべてのガイドロールを低回転抵抗ロールIとしたこと以外は実施例1と同様にして偏光フィルム25(厚み12μm)を作製し、次いで偏光板を作製した。特定凹凸欠陥及び輝点(光抜け)の評価結果を表1に示す。
PVA系樹脂フィルム10として、厚み20μmのポリビニルアルコールフィルムを乾式で4.1倍に一軸延伸してなるPVA系樹脂フィルムbを用いたこと以外はそれぞれ実施例1~3と同様にして偏光フィルム25(厚み7μm)を作製し、次いで偏光板を作製した。特定凹凸欠陥及び輝点(光抜け)の評価結果を表1に示す。
低回転抵抗ロールIを用いることなく、偏光フィルム製造装置が有するフィルムの搬送経路を構築しているガイドロールをすべて上述のガイドロールIIとしたこと以外は実施例1と同様にして偏光フィルム25(厚み12μm)を作製し、次いで偏光板を作製した。特定凹凸欠陥及び輝点(光抜け)の評価結果を表1に示す。
PVA系樹脂フィルム10として、厚み20μmのポリビニルアルコールフィルムを乾式で4.1倍に一軸延伸してなるPVA系樹脂フィルムbを用いたこと以外は比較例1と同様にして偏光フィルム25(厚み7μm)を作製し、次いで偏光板を作製した。特定凹凸欠陥及び輝点(光抜け)の評価結果を表1に示す。
Claims (17)
- ポリビニルアルコール系樹脂フィルムから偏光フィルムを製造するための製造装置であって、
前記ポリビニルアルコール系樹脂フィルムの搬送経路を構成し、前記ポリビニルアルコール系樹脂フィルムの表面に接するように配置される複数のロールと、
前記搬送経路上に配置され、前記ポリビニルアルコール系樹脂フィルムが浸漬される処理液を収容する1以上の処理槽を含む湿式処理部と、
前記搬送経路上に配置され、湿式処理後のポリビニルアルコール系樹脂フィルムを乾燥させるための乾燥処理部と、
を含み、
前記複数のロールは、回転抵抗が0.025N以下である低回転抵抗ロールを含む、製造装置。 - 前記低回転抵抗ロールは、前記湿式処理部から前記乾燥処理部にわたる搬送経路のいずれかの位置に配置される、請求項1に記載の製造装置。
- 前記湿式処理部は、二色性色素を含有する染色処理液を収容する染色処理槽、及び架橋剤を含有する架橋処理液を収容する架橋処理槽をこの順に含み、
前記低回転抵抗ロールは、前記架橋処理槽以降に配置される、請求項2に記載の製造装置。 - 前記低回転抵抗ロールは、水に対する接触角が60度以上である表面を有する、請求項1~3のいずれか1項に記載の製造装置。
- 前記表面は、フッ素系樹脂、シリコン原子含有樹脂、カーボン又はダイヤモンドライクカーボンで構成される、請求項4に記載の製造装置。
- 前記低回転抵抗ロールは、単位体積あたりの重量が1500kg/m3以下である、請求項1~5のいずれか1項に記載の製造装置。
- 前記低回転抵抗ロールは、ガイドロールである、請求項1~6のいずれか1項に記載の製造装置。
- 前記低回転抵抗ロールに接する前記ポリビニルアルコール系樹脂フィルムの厚みが15μm以下である、請求項1~7のいずれか1項に記載の製造装置。
- ポリビニルアルコール系樹脂フィルムから偏光フィルムを製造する方法であって、
前記ポリビニルアルコール系樹脂フィルムの表面に接するように配置される複数のロールによって構成される搬送経路に沿って前記ポリビニルアルコール系樹脂フィルムを搬送させながら、1以上の処理液に浸漬させる湿式処理工程と、
前記搬送経路に沿って前記ポリビニルアルコール系樹脂フィルムを搬送させながら、湿式処理後のポリビニルアルコール系樹脂フィルムを乾燥させる乾燥処理工程と、
を含み、
前記複数のロールは、回転抵抗が0.025N以下である低回転抵抗ロールを含む、製造方法。 - 前記低回転抵抗ロールは、前記湿式処理工程から前記乾燥処理工程にわたる搬送経路のいずれかの位置に配置される、請求項9に記載の製造方法。
- 前記湿式処理工程は、二色性色素を含有する染色処理液に浸漬させる工程と、架橋剤を含有する架橋処理液に浸漬させる工程と、をこの順に含み、
前記低回転抵抗ロールは、前記架橋処理液に浸漬させる工程以降の搬送経路に配置される、請求項10に記載の製造方法。 - 前記低回転抵抗ロールは、水に対する接触角が60度以上である表面を有する、請求項9~11のいずれか1項に記載の製造方法。
- 前記表面は、フッ素系樹脂、シリコン原子含有樹脂、カーボン又はダイヤモンドライクカーボンで構成される、請求項12に記載の製造方法。
- 前記低回転抵抗ロールは、単位体積あたりの重量が1500g/m3以下である、請求項9~13のいずれか1項に記載の製造方法。
- 前記低回転抵抗ロールは、ガイドロールである、請求項9~14のいずれか1項に記載の製造方法。
- 前記低回転抵抗ロールに接する前記ポリビニルアルコール系樹脂フィルムの厚みが15μm以下である、請求項9~15のいずれか1項に記載の製造方法。
- ポリビニルアルコール系樹脂フィルムに二色性色素が吸着配向されている偏光フィルムであって、
少なくとも一方の面における凹凸欠陥の密度が20個/m2以下であり、
前記凹凸欠陥は、前記凹凸欠陥以外の偏光フィルム面を基準にそれより突出している1つの凸部と、前記基準より陥没しており前記凸部に隣接する1つの凹部との組み合わせからなり、長径が0.5~5mmの範囲内である、偏光フィルム。
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Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004078208A (ja) * | 2002-08-02 | 2004-03-11 | Nitto Denko Corp | 偏光フィルムの製造方法、およびそれを用いた偏光フィルムならびに光学フィルム |
JP2009103854A (ja) * | 2007-10-23 | 2009-05-14 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法およびその用途 |
JP2011186085A (ja) * | 2010-03-05 | 2011-09-22 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法 |
JP2012013989A (ja) * | 2010-07-01 | 2012-01-19 | Nitto Denko Corp | 偏光子の製造方法 |
JP2014109740A (ja) * | 2012-12-04 | 2014-06-12 | Sumitomo Chemical Co Ltd | 偏光フィルム及び偏光板の製造方法 |
JP2014142392A (ja) * | 2013-01-22 | 2014-08-07 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法 |
Family Cites Families (7)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP3347245B2 (ja) * | 1995-01-20 | 2002-11-20 | 株式会社リコー | 液塗布装置及び該装置を備えた像形成物質除去装置 |
JP2001141926A (ja) | 1999-11-15 | 2001-05-25 | Nitto Denko Corp | 偏光フィルムの製造方法、偏光板及び表示装置 |
WO2004013667A1 (ja) * | 2002-08-02 | 2004-02-12 | Nitto Denko Corporation | 偏光フィルムの製造方法、およびそれを用いた偏光フィルムならびに光学フィルム |
JP5112268B2 (ja) * | 2007-12-06 | 2013-01-09 | 日東電工株式会社 | 画像表示装置の製造方法 |
KR101166500B1 (ko) * | 2010-06-10 | 2012-07-20 | 황장환 | 3d 광학필름의 배열방법 |
JP2014085383A (ja) * | 2012-10-19 | 2014-05-12 | Cheil Industries Inc | 樹脂膜及び樹脂膜の製造方法 |
JP6066707B2 (ja) * | 2012-12-13 | 2017-01-25 | 日東電工株式会社 | 偏光フィルムの製造方法 |
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Patent Citations (6)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2004078208A (ja) * | 2002-08-02 | 2004-03-11 | Nitto Denko Corp | 偏光フィルムの製造方法、およびそれを用いた偏光フィルムならびに光学フィルム |
JP2009103854A (ja) * | 2007-10-23 | 2009-05-14 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法およびその用途 |
JP2011186085A (ja) * | 2010-03-05 | 2011-09-22 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法 |
JP2012013989A (ja) * | 2010-07-01 | 2012-01-19 | Nitto Denko Corp | 偏光子の製造方法 |
JP2014109740A (ja) * | 2012-12-04 | 2014-06-12 | Sumitomo Chemical Co Ltd | 偏光フィルム及び偏光板の製造方法 |
JP2014142392A (ja) * | 2013-01-22 | 2014-08-07 | Sumitomo Chemical Co Ltd | 偏光フィルムの製造方法 |
Cited By (2)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JP2020034595A (ja) * | 2018-08-27 | 2020-03-05 | 日東電工株式会社 | 延伸樹脂膜の製造方法、偏光子の製造方法、延伸樹脂膜の水分率を測定する方法、および延伸樹脂膜の製造装置 |
JP2020034596A (ja) * | 2018-08-27 | 2020-03-05 | 日東電工株式会社 | 延伸樹脂膜の製造方法、偏光子の製造方法、および延伸樹脂膜の製造装置 |
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