WO2010106901A1 - 光学フィルムの製造方法、光学フィルム及び光学フィルムの製造装置 - Google Patents
光学フィルムの製造方法、光学フィルム及び光学フィルムの製造装置 Download PDFInfo
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- WO2010106901A1 WO2010106901A1 PCT/JP2010/053231 JP2010053231W WO2010106901A1 WO 2010106901 A1 WO2010106901 A1 WO 2010106901A1 JP 2010053231 W JP2010053231 W JP 2010053231W WO 2010106901 A1 WO2010106901 A1 WO 2010106901A1
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
- B29C33/60—Releasing, lubricating or separating agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
- B29C33/58—Applying the releasing agents
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C33/00—Moulds or cores; Details thereof or accessories therefor
- B29C33/56—Coatings, e.g. enameled or galvanised; Releasing, lubricating or separating agents
- B29C33/60—Releasing, lubricating or separating agents
- B29C33/62—Releasing, lubricating or separating agents based on polymers or oligomers
- B29C33/64—Silicone
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C43/00—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor
- B29C43/22—Compression moulding, i.e. applying external pressure to flow the moulding material; Apparatus therefor of articles of indefinite length
- B29C43/30—Making multilayered or multicoloured articles
- B29C43/305—Making multilayered articles
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/03—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor characterised by the shape of the extruded material at extrusion
- B29C48/07—Flat, e.g. panels
- B29C48/08—Flat, e.g. panels flexible, e.g. films
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/911—Cooling
- B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
- B29C48/915—Cooling of flat articles, e.g. using specially adapted supporting means with means for improving the adhesion to the supporting means
- B29C48/9155—Pressure rollers
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C55/00—Shaping by stretching, e.g. drawing through a die; Apparatus therefor
- B29C55/02—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets
- B29C55/10—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial
- B29C55/12—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial
- B29C55/14—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively
- B29C55/143—Shaping by stretching, e.g. drawing through a die; Apparatus therefor of plates or sheets multiaxial biaxial successively firstly parallel to the direction of feed and then transversely thereto
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29C—SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING
- B29C48/00—Extrusion moulding, i.e. expressing the moulding material through a die or nozzle which imparts the desired form; Apparatus therefor
- B29C48/25—Component parts, details or accessories; Auxiliary operations
- B29C48/88—Thermal treatment of the stream of extruded material, e.g. cooling
- B29C48/911—Cooling
- B29C48/9135—Cooling of flat articles, e.g. using specially adapted supporting means
- B29C48/914—Cooling of flat articles, e.g. using specially adapted supporting means cooling drums
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29K—INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR MOULDS, REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- B29K2001/00—Use of cellulose, modified cellulose or cellulose derivatives, e.g. viscose, as moulding material
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B29—WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE IN GENERAL
- B29L—INDEXING SCHEME ASSOCIATED WITH SUBCLASS B29C, RELATING TO PARTICULAR ARTICLES
- B29L2007/00—Flat articles, e.g. films or sheets
Definitions
- the present invention relates to an optical film manufacturing method, a manufacturing apparatus, and an optical film for manufacturing an optical film containing a thermoplastic resin such as a cellulose resin by a melt casting film forming method.
- Liquid crystal display devices are widely used as monitors because they save space and energy compared to conventional CRT display devices. Furthermore, it is also spreading for TV.
- various optical films such as a protective film for a polarizing plate and a retardation film are used.
- the protective film for the polarizing plate is a film for protecting the polarizing film by being attached to a polarizing film made of stretched polyvinyl alcohol or the like, and a film containing a thermoplastic resin such as a cellulose resin is used.
- the retardation film is used for the purpose of, for example, widening the viewing angle and improving the contrast, and is provided with retardation by stretching a film containing a thermoplastic resin such as a cellulose resin. Sometimes called an optical compensation film.
- Such optical film production methods are roughly classified into a melt casting film forming method and a solution casting film forming method.
- the former is a method in which a melt obtained by heating and melting a thermoplastic resin is cast on a support, solidified by cooling, and further stretched as necessary to form a film.
- the latter is a method in which a polymer is dissolved in a solvent. Then, the solution is cast on a support, the solvent is evaporated, and the film is stretched as necessary to form a film.
- the production by the solution casting film forming method has been mainly used because the film thickness can be easily uniformed.
- the solution casting film forming method has problems such as requiring huge production facilities for the recovery of the solvent, the production of an optical film by the melt casting film forming method free from these problems has attracted attention. It came to be.
- optical films are required to have uniform optical performance, particularly retardation.
- retardation uniformity has become increasingly demanding, and optical films have become increasingly demanding for wider widths, thinner films, and smooth surfaces.
- a melt containing a thermoplastic resin such as a cellulose resin is extruded from a casting die onto the surface of a rotating support (hereinafter also referred to as a cast roll) and extruded.
- a film is obtained by sandwiching a film-like melt (hereinafter also referred to as a film) with a rotating support and a pressure-rotating body (hereinafter also referred to as a touch roll).
- the surface of the touch roll is mirror-finished to increase the surface smoothness of the film.
- the width of the optical film increases, the width of the casting die also increases, making it difficult to sandwich the extruded film-like melt with a uniform pressure between the cast roll and the touch roll. .
- Patent Document 1 As a method of coping with such problems, a method of making the pressure when pinching uniform using an elastic roll having a metal cylinder on the outer periphery of the touch roll (hereinafter also referred to as an elastic metal roll),
- an elastic metal roll By setting the temperature of the melt flowing down from the casting die to the cast roll higher than before, even if the sandwiching pressure between the cast roll and the touch roll is somewhat uneven, the retardation unevenness is reduced. Methods of suppressing have been proposed.
- an object of the present invention is to improve the releasability of a film from a touch roll and to produce an optical film, an optical film manufacturing apparatus, and an optical film manufactured by the manufacturing method, in which horizontal unevenness and retardation unevenness do not occur Is to provide.
- the present invention has the following features.
- the method for producing an optical film comprising: a film-like melt extruded in the casting process, and a pinching step of pinching the film-like melt with the rotary support and the pinching rotary body
- a method for producing an optical film comprising applying a releasability adjusting agent for improving the releasability between the sandwiched rotating body and the film-like melt to the surface of the sandwiched rotating body.
- the contact angle S1 between the surface of the rotary support and water and the contact angle S2 between the surface of the pinching rotary body after applying the mold release adjusting agent and water are 0.5 ° ⁇ S2-S1.
- thermoplastic resin is a cellulose ester resin.
- a casting die that extrudes a melt containing a thermoplastic resin in the form of a film on the surface of the rotary support, and a film-like melt that is extruded by the casting die is sandwiched between the rotary support and the clamping rotary body.
- mold release property adjustment is performed on the surface of the pressing rotary body to improve the release characteristics of the pressing rotary body and the film-like melt.
- An apparatus for producing an optical film comprising: a releasability adjusting agent coating device for coating the agent.
- the film-like melt is sandwiched between the rotary support and the sandwiching rotary body after the release adjuster is applied to the surface of the sandwiching rotary body.
- the releasability of is improved. Therefore, when the film is peeled from the sandwiching rotary body, it is possible to provide an optical film manufacturing method, an optical film manufacturing apparatus, and an optical film manufactured by the manufacturing method, in which horizontal unevenness and retardation unevenness do not occur.
- a casting process in which a melt containing a thermoplastic resin is extruded from a casting die onto the surface of a rotary support (cast roll) as a film, and a film extruded in the casting process
- a method for producing an optical film comprising a pressing step in which a molten melt is pinched by a rotary support and a pinching rotary member (touch roll), the pinching rotary member and the film are formed on the surface of the pinching rotary member. It is a manufacturing method of an optical film characterized by applying a releasability adjusting agent for improving releasability with a molten material.
- FIG. 1 shows a schematic diagram of a casting process and a pinching process of a manufacturing apparatus according to an embodiment using the method for manufacturing an optical film of the present invention.
- the melt Y containing a thermoplastic resin is extruded from the casting die 4 as casting means to the position P1 on the cast roll 5.
- the releasability adjusting agent 104 is applied to the surface of the touch roll 6 by the releasability adjusting agent application device 100 on the upstream side from the position of the pinching portion P2.
- the melt Y extruded from the casting die 4 to the position P1 on the cast roll 5 is pinched by the touch roll 6 and the cast roll 5 which are the pinching means at the position P2 as a pinching process.
- the sandwiched melt is formed into a film and conveyed on the cast roll 5 and peeled off at the position P3, and the process proceeds to the next step.
- the releasability adjusting agent coating apparatus 100 pumps up the liquid releasability adjusting agent 104 in the storage tank 105 heated to a predetermined temperature by the pumping roller 102 and regulates it to a certain amount by the regulating blade 103.
- the releasability adjusting agent 104 on the subsequent drawing roller 102 is transferred to the application roller 101 and applied onto the touch roll 6.
- the mold release adjuster is applied to the surface of the touch roll 6, and then the film and the cast roll are pinched by the cast roll 5 and the touch roll 6 in the pinching step.
- 5 becomes larger than the adhesive force between the film and the touch roll 6, and the occurrence of defective peeling when the touch roll 6 and the film peel can be suppressed.
- the surface of the touch roll 6 is mirror-finished to increase the smoothness of the film surface, or when an elastic metal roll is used as the touch roll, and also eliminates uneven pressing in the pinching process and reduces the residual phase difference. Therefore, when the film temperature is increased and the film is sandwiched and the like, a peeling failure between the touch roll and the film is likely to occur.
- the present invention can effectively eliminate the peeling failure.
- the releasability adjusting agent is applied only to the touch roll 6, but the releasability adjusting agent may be applied to both surfaces of the touch roll 6 and the cast roll 5. It is sufficient that the adhesive force between the cast roll 5 and the cast roll 5 is adjusted so as to be larger than the adhesive force between the film and the touch roll 6, and generation of defective peeling when the touch roll 6 and the film peel can be suppressed.
- the releasability adjusting agent according to the present invention is not particularly limited as long as it is a material that improves the releasability between the touch roll 6 and the film, and may be either liquid or solid, and is necessary as a product. It is preferable if it does not adversely affect the optical film characteristics. More preferably, the same material as the additive used for the optical film is preferably used as the releasability adjusting agent. By using a releasability adjusting agent of the same material as such an additive, even if the releasability adjusting agent applied to the touch roll 6 adheres to the surface of the optical film, it adversely affects the optical film characteristics. There is almost no and the peeling defect of the touch roll 6 and a film can be eliminated effectively.
- the releasability adjusting agent examples include silicon oil, dimethylsiloxane, dichloromethane, a plasticizer used as an additive for an optical film, and an ultraviolet absorber. Further, a liquid in which organic or inorganic fine particles are dispersed may be used.
- the boiling point of the releasability adjusting agent is preferably 150 to 250 ° C. If the boiling point is within this range, the surface temperature of the touch roll 6 is lower than 150 ° on the surface of the touch roll 6, so that the release property adjusting agent becomes liquid or solid, and functions as a release property adjusting agent,
- the releasability adjusting agent transferred to the surface of the film released from the touch roll 6 can be volatilized by making it higher than the boiling point in a process that becomes a high temperature such as a subsequent stretching process, and the releasability on the film surface. It is preferable because the adjusting agent does not remain and the performance as an optical film can be maintained.
- an ultraviolet absorber is particularly preferable.
- the ultraviolet absorber is preferable because it has high releasability and exhibits releasability with such a thin layer, so that the smoothness of the film surface released from the touch roll 6 is also improved. Furthermore, since it is a constituent material of an optical film that is originally added to the optical film, it is preferable that even if it is mixed in the optical film in the manufacturing process, it does not affect the optical film characteristics.
- the coating thickness of the releasability adjusting agent applied to the surface of the touch roll is preferably 0.05 to 1000 ⁇ m. By setting the coating film thickness within this range, the coating film thickness is too small, or the coating film is too thick and the releasability adjusting agent stays between the touch roller and the cooling roller. This is preferable because there is little risk of causing horizontal unevenness and retardation unevenness.
- the contact angle S1 between the surface of the cast roll 5 and water and the contact angle S2 between the surface of the touch roll 6 and the water after applying the releasability adjusting agent are 0.5 ° ⁇ S2-S1 ⁇ .
- a relationship of 100 ° is preferable.
- the contact angle between the surface of the roll and water is measured at 23 ° C. and 50% RH using a fully automatic contact angle meter “CA-W type roll special model” (manufactured by Kyowa Interface Science Co., Ltd.). Measure under the environment. In order to achieve both the change in the measured value due to the evaporation of pure water and the stability of the measurement, the measurement is completed within 5 to 30 seconds after the dropping of the pure water. The measurement is based on the ⁇ / 2 method for obtaining the contact angle from the angle of the straight line connecting the left and right end points and the vertex of the droplet to the solid surface. The measurement is from a direction perpendicular to the axial direction of the roller, and the dropping amount is set to 70 ⁇ l.
- Measured locations are 3 locations at 5cm from the center and the left and right ends of the roll, measuring 4 locations at 90 ° in the circumferential direction, a total of 12 locations, and taking this average value as the contact angle.
- the transport tension of the film-like melt when the touch roll 6 is pressed against the cast roll 5 is T1
- the transport tension of the film-like melt when the touch roll 6 is not pressed against the cast roll 5 is T2.
- the value of T1-T2 is preferably 1 to 250N.
- the conveyance tension is measured with and without a load meter for applying a load in the vertical direction at both ends of the nearest roller shaft on the downstream side of the cast roll 5 and pressing the touch roll 6 against the cast roll 5. The difference between each load cell was calculated, and the total value was taken as T1-T2.
- T1-T2 that is the difference in transport tension within the above range
- the film peeled off from the touch roll 6 can be stably transported without the possibility of occurrence of film thickness unevenness due to fluttering or breakage due to excessive pulling.
- the film when producing an optical film having a film thickness of 40 ⁇ m or less, the film can be more stably conveyed by making the peelability from the touch roll 6 good and the conveyance tension within the above range. A smooth film free from unevenness and retardation unevenness can be obtained, which is preferable.
- the manufacturing method of the present invention improves the peeling failure between the touch roll and the film, and an optical film free from horizontal unevenness and retardation unevenness on the film surface can be obtained.
- thermoplastic resin film is formed by a melt casting film forming method in which a molten resin is cast to form a film.
- the main materials of the optical film according to the present invention include preferable requirements such as easy manufacture, good adhesion to the polarizing film, and optical transparency.
- thermoplastic resin film having the above properties is not particularly limited.
- cellulose ester films such as cellulose diacetate film, cellulose triacetate film, cellulose acetate butyrate film, and cellulose acetate propionate film
- polyester Film polycarbonate film, polyarylate film, polysulfone (including polyethersulfone) film, polyester film such as polyethylene terephthalate and polyethylene naphthalate, polyethylene film, polypropylene film, cellophane, polyvinylidene chloride film, polyvinyl alcohol film , Ethylene vinyl alcohol film, syndiotactic polystyrene film, poly -Bonate film, cycloolefin polymer film, ZEONEX (trade name, manufactured by ZEON CORPORATION), ZEONOR (trade name, manufactured by ZEON CORPORATION), polymethylpentene film, polyetherketone film, polyetherketoneimide film, polyamide film , Fluororesin film, nylon film, polymethyl
- a cellulose ester film, a cycloolefin polymer film, a polycarbonate film, and a polysulfone (including polyethersulfone) film are preferable.
- a cellulose ester resin film or a cyclic olefin addition polymer is used.
- a resin film containing 80% or more is preferably used from the viewpoints of production, cost, transparency, adhesiveness, and the like.
- the materials constituting the optical film of the present invention include these resins, and if necessary, stabilizers, plasticizers, ultraviolet absorbers, matting agents as slip agents, and retardation control agents. These materials are appropriately selected depending on the required characteristics of the target optical film.
- the cellulose resin When a cellulose resin is used as the material of the optical film of the present invention, the cellulose resin has a cellulose ester structure, and includes at least one of a fatty acid acyl group and a substituted or unsubstituted aromatic acyl group.
- a single or mixed acid ester of cellulose hereinafter, simply referred to as “cellulose resin”), which is amorphous.
- cellulose resin A single or mixed acid ester of cellulose (hereinafter, simply referred to as “cellulose resin”), which is amorphous.
- “Amorphous” means a substance that is not a crystal but has a solid state in an irregular molecular arrangement, and represents a crystalline state at the time of the raw material.
- cellulose resin useful for the use of the present invention is exemplified in JP-A-2007-989817, it is not limited thereto.
- the cellulose resin used in the present invention has few bright spot foreign substances when formed into a film.
- Bright spot foreign matter means that two polarizing plates are arranged orthogonally (crossed Nicols), a cellulose ester film is arranged between them, and the slow axis of the polarizing plate protective film is placed on the transmission axis of the polarizing plate on one light source side.
- the polarizing plate used for the evaluation is desirably composed of a protective film having no bright spot foreign matter, and a polarizing plate using a glass plate for protecting the polarizer is preferably used.
- the bright spot foreign matter is considered to be one of the reasons that the esterification part of the hydroxyl group contained in the cellulose resin is unreacted, and using a cellulose resin with few bright spot foreign substances and filtering the heated and melted cellulose resin Can remove foreign matter and reduce bright spot foreign matter. Moreover, the number of bright spot foreign matter per unit area decreases as the film thickness decreases, and the bright spot foreign matter tends to decrease as the content of the cellulose resin contained in the film decreases.
- the number of bright spots is preferably 300 or less and 0 bright spots with a size of 5 to 50 ⁇ m recognized in the polarization crossed Nicol state per area of 250 mm 2 and no more than 50 ⁇ m. More preferably, the number of bright spots of 5 to 50 ⁇ m is 200 or less.
- the retardation film functions as a polarizing plate protective film, the presence of the bright spot is a factor of disturbance of birefringence, and the adverse effect on the image becomes large.
- a melt casting film forming step can be continuously performed including a bright spot foreign matter removing step.
- the melt casting film forming method including the filtration process of bright spot foreign matters by heat melting lowers the heat melting temperature when a plasticizer and a cellulose resin described later are used as a composition compared to a system in which no plasticizer is added. This is a preferable method from the viewpoint and from the viewpoint of improving the removal efficiency of bright spot foreign matter and avoiding thermal decomposition. Moreover, what mixed the ultraviolet absorber and the mat agent suitably as another additive mentioned later can also be filtered similarly.
- the filter medium conventionally known materials such as glass fibers, cellulose fibers, filter paper, fluororesins such as tetrafluoroethylene resin are preferably used, and ceramics, metals and the like are particularly preferably used.
- the absolute filtration accuracy is 50 ⁇ m or less, preferably 30 ⁇ m or less, more preferably 10 ⁇ m or less, and still more preferably 5 ⁇ m or less. These can be used in combination as appropriate.
- Mixing a constituent material other than the cellulose resin of the film constituent material uniformly with the resin can contribute to providing a uniform meltability in the meltability at the time of heating.
- Polymeric materials and oligomers other than cellulose resin may be appropriately selected and mixed with cellulose resin.
- a polymer material or oligomer preferably has excellent compatibility with the cellulose resin, and the transmittance is 80% or more, preferably 90% or more, more preferably over the entire visible region (400 nm to 800 nm) when formed into a film. Is 92% or more.
- the purpose of mixing at least one of polymer materials and oligomers other than the cellulose resin includes meanings for the purpose of improving viscosity control during heating and melting and improving film physical properties after film processing. This polymer material and oligomer may be regarded as other concepts as additives.
- additives used for the optical film will be described. These additives can be used as a releasability adjusting agent.
- plasticizer preferably used, in the phosphate ester type, triphenyl phosphate, tricresyl phosphate, cresyl diphenyl phosphate, octyl diphenyl phosphate, diphenyl biphenyl phosphate, trioctyl phosphate, tributyl phosphate, etc.
- phthalate ester type Diethyl phthalate, dimethoxyethyl phthalate, dimethyl phthalate, dioctyl phthalate, dibutyl phthalate, di-2-ethylhexyl phthalate, etc. It is preferable to use ruethyl glycolate, butyl phthalyl butyl glycolate or the like.
- the above plasticizers may be used in combination of two or more as required.
- a phosphate ester plasticizer in an amount of 50% by mass or less because it hardly causes hydrolysis of the cellulose ester resin film and is excellent in durability. It is more preferable that the phosphate ester plasticizer ratio is small, and it is particularly preferable to use only a phthalate ester or glycolate ester plasticizer.
- the amount of the plasticizer to be added in order to make the water absorption rate and moisture content within a specific range is 3 to 30% by mass, more preferably 10 to 25% by mass, based on the cellulose ester resin. More preferably, it is 15 to 25% by mass.
- the addition amount of the plasticizer exceeds 30% by mass, the mechanical strength and dimensional stability of the cellulose ester-based resin film deteriorate, which is not preferable.
- hindered phenol compounds are suitable. Specific examples thereof include 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5- Di-t-butyl-4-hydroxyphenyl) propionate], triethylene glycol-bis [3- (3-t-butyl-5-methyl-4-hydroxyphenyl) propionate], 1,6-hexanediol-bis [ 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], 2,4-bis- (n-octylthio) -6- (4-hydroxy-3,5-di-t-butylanilino) 1,3,5-triazine, 2,2-thio-diethylenebis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate], octade 3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate, 1,
- 2,6-di-t-butyl-p-cresol, pentaerythrityl-tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] and triethylene glycol-bis [3- (3-tert-butyl-5-methyl-4-hydroxyphenyl) propionate] is preferred.
- hydrazine-based metal deactivators such as N, N′-bis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionyl] hydrazine and tris (2,4-di-t
- a phosphorus processing stabilizer such as -butylphenyl phosphite may be used in combination.
- the amount of these compounds added is preferably from 1 ppm to 1.0%, particularly preferably from 10 to 1000 ppm, by weight, based on the cellulose ester resin.
- an ultraviolet absorber it is preferable to add an ultraviolet absorber to the cellulose ester resin film.
- the ultraviolet absorber the absorption ability of ultraviolet rays having a wavelength of 370 nm or less is excellent from the viewpoint of preventing deterioration of the liquid crystal, and the absorption of visible light having a wavelength of 400 nm or more is as little as possible from the viewpoint of good liquid crystal display properties. Those are preferably used.
- the transmittance of ultraviolet rays at a wavelength of 370 nm is preferably 10% or less, more preferably 5% or less, and even more preferably 2% or less.
- ultraviolet absorber examples include, but are not limited to, oxybenzophenone compounds, benzotriazole compounds, salicylic acid ester compounds, benzophenone compounds, cyanoacrylate compounds, nickel complex compounds, and the like.
- ultraviolet absorbers which may contain two or more different ultraviolet absorbers.
- Preferably used ultraviolet absorbers include benzotriazole ultraviolet absorbers and benzophenone ultraviolet absorbers.
- An embodiment in which a benzotriazole-based ultraviolet absorber with less unnecessary coloring is added to the cellulose ester-based resin film is particularly preferable.
- the addition method of the ultraviolet absorber may be added to the dope after dissolving the ultraviolet absorber in an organic solvent such as alcohol, methylene chloride, dioxolane, or may be added directly to the dope composition.
- an organic solvent such as alcohol, methylene chloride, dioxolane
- a dissolver or a sand mill is used in the organic solvent and the cellulose ester resin to disperse and then added to the dope.
- the amount of the ultraviolet absorber used is 0.1 to 2.5% by mass, preferably 0.5 to 2.0% by mass, more preferably 0.8 to 2.0% by mass, based on the cellulose ester resin. % By mass.
- the usage-amount of a ultraviolet absorber exceeds 2.5 mass%, there exists a tendency for the transparency of a cellulose-ester-type resin film to worsen, and it is unpreferable.
- fine particles may be added to the cellulose ester resin film as a matting agent in order to prevent the films from sticking to each other or to impart slipperiness to facilitate handling.
- the type of fine particles may be an inorganic compound or an organic compound.
- the fine particles of the inorganic compound include fine particles of silicon dioxide, titanium dioxide, aluminum oxide, zirconium oxide, tin oxide and the like. In this, it is preferable that it is a compound containing a silicon atom, and especially a silicon dioxide fine particle is preferable.
- silicon dioxide fine particles for example, Aerosil manufactured by Aerosil Co., Ltd., 200V, 300, R972, R972V, R974, R976, R976S, R202, R812, R805, OX50, TT600, RY50, RX50, NY50, NAX50, NA50H, NA50Y, NX90, RY200S, RY200, RX200, R8200, RA200H, RA200HS, NA200Y, R816, R104, RY300, RX300, R106, and the like.
- AEROSIL-200V and R972V are preferable in terms of controlling dispersibility and particle size.
- the average particle size of the fine particles in the film is preferably 50 nm to 2 ⁇ m from the viewpoint of imparting slipperiness and ensuring transparency.
- the thickness is preferably 100 nm to 1000 nm, more preferably 100 nm to 500 nm.
- the average particle diameter in the film can be confirmed by taking and observing a cross-sectional photograph.
- the primary particle size, the particle size after being dispersed in a solvent, and the particle size after being added to a film often change. And controlling the particle size formed by aggregation and aggregation.
- the amount of fine particles added is 0.02 to 0.5% by mass, preferably 0.04 to 0.3% by mass, based on the cellulose ester resin film.
- FIG. 2 is a schematic flow sheet of a first embodiment of an apparatus for carrying out the method for producing an optical film of the present invention using a melt casting film forming method.
- a film material containing a resin such as a cellulose resin is mixed to obtain a resin mixture, which is then extruded from the casting die 4 onto the cast roll 5 using the extruder 1.
- a predetermined amount of a UV absorber is applied as a release property adjusting agent 104 by a release property adjusting agent application device 100.
- the extruded film-like melt circumscribes the cast roll 5 and is pressed against the surface of the cast roll 5 by the touch roll 6 with a predetermined pressure.
- the cooling rolls 7 and 8 are circumscribed in order to be cooled and solidified, and are peeled off by the peeling roll 9.
- the peeled film 17 is stretched in the longitudinal (conveying direction) and lateral (lateral direction) of the film by the longitudinal stretching apparatus 10 and the lateral stretching apparatus 20 and then wound by the winding apparatus 60.
- the melt containing the film-like thermoplastic resin extruded from the casting die 4 is extruded onto the cast roll 5 having a cooling function, and is sandwiched between the touch rolls 6 and cooled and subjected to surface correction.
- the cast roll 5 and the touch roll 6 are not limited to rolls, and may be drums or belts.
- the temperature of the cast roll 5 is preferably set to be equal to or lower than the glass transition temperature (Tg) of the resin mixture and equal to or higher than the melting point of the additive.
- the touch roll 6 is a rotating body intended to sandwich the film in the direction of the cast roll 5 from the opposite side of the cast roll 5 with respect to the film.
- the surface of the touch roll 6 is preferably a metal, and the thickness is 1 mm to 10 mm. It is preferably 2 mm to 6 mm.
- the surface of the sandwiching rotary body is subjected to a treatment such as chrome plating, and the surface roughness is preferably 0.1 ⁇ m or less, and more preferably 0.05 ⁇ m or less, at the maximum height Ry. The smoother the roll surface, the smoother the surface of the resulting film.
- the touch roll 6 is preferably made of an elastic roll (elastic metal roll) having a metal cylinder on the outer periphery.
- an elastic touch roll having a metal cylinder on the outer periphery as described above is preferable.
- the metal material on the surface of the touch roll 6 is required to be smooth, moderately elastic, and durable. Carbon steel, stainless steel, titanium, nickel produced by electroforming, etc. can be preferably used. Further, in order to increase the hardness of the surface or to improve the releasability with the resin, it is preferable to perform a surface treatment such as hard chrome plating, nickel plating, amorphous chrome plating, or ceramic spraying. It is preferable that the surface processed is further polished to have the above-described surface roughness.
- the touch roll 6 has a double structure of a metal outer cylinder and an inner cylinder, and has a double cylinder configuration having a space so that a cooling fluid can flow between them.
- the inner cylinder is preferably a lightweight and rigid metallic inner cylinder such as carbon steel, stainless steel, aluminum, titanium or the like. By giving rigidity to the inner cylinder, it is possible to suppress the rotational shake of the roll. A sufficient rigidity can be obtained by setting the thickness of the inner cylinder to 2 to 10 times that of the outer cylinder.
- the inner cylinder may be further coated with a resin elastic material such as silicone or fluororubber.
- the structure of the space through which the cooling fluid flows can be any structure as long as the temperature of the roll surface can be uniformly controlled.
- the roll can be made to flow in a spiral direction by flowing alternately and back in the width direction. Temperature control with a small surface temperature distribution is possible.
- the cooling fluid is not particularly limited, and water or oil can be used according to the temperature range to be used.
- the touch roll 6 is set to a drum shape in which the outer diameter at the center is larger than the outer diameter at both ends.
- the touch roll generally presses both ends of the touch roll against the film with a pressurizing unit, but in this case, the touch roll is bent, so that there is a phenomenon that the touch roll is pressed more strongly toward the end. Highly uniform pressing is possible by making the roll into a drum shape.
- the diameter of the touch roll 6 is preferably in the range of 200 mm to 500 mm.
- the effective width of the touch roll 6 needs to be wider than the film width to be pinched. Due to the difference between the radius of the center portion of the touch roll 6 and the radius of the end portion (hereinafter referred to as the crowning amount), unevenness such as streaks generated at the center portion of the film can be prevented.
- the amount of crowning is preferably in the range of 50 to 300 ⁇ m.
- the cast roll 5 and the touch roll 6 are installed at positions opposite to the plane of the film so as to sandwich the film.
- the cast roll 5 and the touch roll 6 may be in contact with the film by a surface or by a line.
- a predetermined amount of releasability adjusting agent 104 is applied to the surface of the touch roll 6 by the releasability adjusting agent application device 100 before the film on the cast roll 5 is pressed.
- the application of the releasability adjusting agent 04 has been described in detail above, and therefore will not be described here.
- the conditions for melt extrusion can be performed in the same manner as the conditions used for other thermoplastic resins such as polyester.
- the material is preferably dried beforehand. It is desirable to dry the moisture to 1000 ppm or less, preferably 200 ppm or less, using a vacuum or reduced pressure dryer or a dehumidifying hot air dryer.
- a cellulose ester resin dried under hot air, vacuum or reduced pressure is melted at an extrusion temperature of about 200 to 300 ° C. using an extruder 1 and filtered through a leaf disk type filter 2 to remove foreign matters.
- additives such as plasticizer are not mixed in advance, they may be kneaded in the middle of the extruder. In order to add uniformly, it is preferable to use a mixing apparatus such as a static mixer 3.
- a resin such as a cellulose resin and other additives such as a stabilizer added as necessary are mixed before melting.
- Mixing may be performed by a mixer or the like, or as described above, mixing may be performed in a resin preparation process such as a cellulose resin.
- a general mixer such as a V-type mixer, a conical screw type mixer, a horizontal cylindrical type mixer, or the like can be used.
- the mixture may be melted directly using the extruder 1 to form a film.
- the pellets are extruded.
- the film may be melted by the machine 1 to form a film.
- a so-called braided semi-melt is once produced at a temperature at which only the material having a low melting point is melted, and the semi-melt is supplied to the extruder 1. It is also possible to form a film by introducing it.
- the film component contains a material that is easily pyrolyzed, in order to reduce the number of times of melting, a method of directly forming a film without producing pellets, or after making a paste-like semi-molten material as described above A method of forming a film is preferred.
- the extruder 1 can use various types of extruders available on the market, but is preferably a melt-kneading extruder, and may be a single-screw extruder or a twin-screw extruder.
- a twin-screw extruder When forming a film directly without producing pellets from film constituent materials, it is preferable to use a twin-screw extruder because an appropriate degree of kneading is necessary, but even with a single-screw extruder, the screw shape is a Maddock type. By changing to a kneading type screw such as a unimelt type or a dull mage, moderate kneading can be obtained, so that it can be used.
- a pellet or braided semi-melt When a pellet or braided semi-melt is once used as a film constituent material, it can be used in either a single screw extruder or a twin screw extruder.
- the cooling step is preferably performed by substituting with an inert gas such as nitrogen gas or reducing the pressure to reduce the oxygen concentration.
- the melting temperature of the film constituent material in the extruder 1 varies depending on the viscosity and discharge amount of the film constituent material, the thickness of the sheet to be produced, etc., but generally the glass transition temperature Tg of the film (resin mixture). On the other hand, it is Tg or more and Tg + 100 ° C. or less, preferably Tg + 10 ° C. or more and Tg + 90 ° C. or less.
- the melt viscosity at the time of extrusion is 1 to 10000 Pa ⁇ s, preferably 10 to 1000 Pa ⁇ s.
- the residence time of the film constituting material in the extruder 1 is preferably short, and is within 5 minutes, preferably within 3 minutes, more preferably within 2 minutes. The residence time depends on the type of the extruder 1 and the extrusion conditions, but can be shortened by adjusting the material supply amount, L / D, screw rotation speed, screw groove depth, and the like. is there.
- the shape of the screw and the number of revolutions of the extruder 1 are appropriately selected depending on the viscosity and the discharge amount of the film constituent material.
- the shear rate in the extruder 1 is 1 / second to 10,000 / second, preferably 5 / second to 1000 / second, more preferably 10 / second to 100 / second.
- an extruder generally marketed as a plastic molding machine can be used as the extruder 1.
- the film constituting material extruded from the extruder 1 is sent to the casting die 4 and extruded from the casting die 4 into a film shape.
- the melt discharged from the extruder 1 is supplied to the casting die 4.
- the casting die 4 is not particularly limited as long as it is used for producing a sheet or a film.
- the material of the casting die 4 is sprayed or plated with hard chromium, chromium carbide, chromium nitride, titanium carbide, titanium carbonitride, titanium nitride, super steel, ceramic (tungsten carbide, aluminum oxide, chromium oxide), etc.
- Processing includes buffing, lapping using a # 1000 or higher grinding wheel, plane cutting using a diamond grinding wheel of # 1000 or higher (the cutting direction is perpendicular to the resin flow direction), electrolytic polishing, and electrolytic composite polishing. And the like.
- a preferable material of the lip portion of the casting die 4 is the same as that of the casting die 4.
- the surface accuracy of the lip is preferably 0.5S or less, and more preferably 0.2S or less.
- the molten resin mixture is extruded onto a film-like resin from a casting die 4 attached to an extruder, and the extruded film-like resin is brought into close contact with a cast roll 5 and a touch roll 6 and is pressed and taken out. Process.
- the temperature decrease from when the melt in the form of film first contacts the surface of the cast roll 5 until it contacts the surface of the touch roll 6 is within 20 ° C. If the temperature drop from when the film first contacts the surface of the cast roll 5 until it touches the surface of the touch roll 6 is too large, the unevenness of the film thickness increases due to uneven shrinkage. On the other hand, if the temperature when the film contacts the touch roll 6 is too low, the flatness of the film and the film thickness unevenness cannot be sufficiently corrected even if the film is pressed by the touch roll 6 due to the high viscosity of the film.
- Preferred materials for the cast roll 5 and the touch roll 6 include carbon steel and stainless steel. Further, the surface accuracy is preferably increased, and the surface roughness is preferably 0.1 ⁇ m or less in terms of the maximum height Ry, and more preferably 0.05 ⁇ m or less.
- the touch roll 6 preferably presses the film against the cast roll 5 by pressing means.
- the linear pressure with which the touch roll 6 presses the film at this time can be adjusted by a hydraulic piston or the like, and is preferably 0.1 to 100 N / mm, more preferably 1 to 50 N / mm.
- the cast roll 5 or the touch roll 6 can be made to have a thin roll diameter or a flexible roll surface in order to improve the uniformity of adhesion with the film.
- the reduced pressure is preferably 50 kPa or more and 70 kPa or less.
- the suction device is preferably subjected to a treatment such as heating with a heater so that the device itself does not become a place where the sublimate is attached. If the suction pressure is too small, the sublimate cannot be sucked effectively, so it is necessary to set the suction pressure appropriately.
- a film-like cellulose ester resin in a molten state from the casting die 4 is sequentially brought into close contact with the cast roll 5, the cooling roll 7 and the cooling roll 8 and is cooled and solidified while being conveyed to obtain a cellulose ester resin film 17.
- the cooled and solidified film 17 peeled from the cooling roll 8 by the peeling roll 9 is introduced into the longitudinal stretching apparatus 10 and roll-stretched in the transport direction (MD direction).
- the film after longitudinal stretching is guided to a lateral stretching apparatus (tenter) 20 where the film 17 is stretched in the lateral direction (width direction).
- a lateral stretching apparatus (tenter) 20 where the film 17 is stretched in the lateral direction (width direction).
- the molecules in the film are oriented.
- the end of the film 17 is slit to a product width by the slitter 19 and cut off, and then knurled (embossing) is applied to both ends of the film by a knurling apparatus comprising an embossing ring 53 and a back roll 52.
- a knurling apparatus comprising an embossing ring 53 and a back roll 52.
- the knurling method can process a metal ring having an uneven pattern on its side surface by heating or pressing.
- the grip part of the clip of the both ends of a film is deform
- the winding machine to be used may be a commonly used winding machine, and can be wound by a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress.
- a winding method such as a constant tension method, a constant torque method, a taper tension method, or a program tension control method with a constant internal stress.
- the thickness of the protective film is preferably 10 to 500 ⁇ m.
- the lower limit is 20 ⁇ m or more, preferably 35 ⁇ m or more.
- the upper limit is 150 ⁇ m or less, preferably 120 ⁇ m or less.
- a particularly preferred range is 35 to 90 ⁇ m.
- the retardation film is thick, the polarizing plate after polarizing plate processing becomes too thick, and is not suitable for the purpose of thin and light in liquid crystal displays used for notebook personal computers and mobile electronic devices.
- the retardation film is thin, it is difficult to express retardation as a retardation film, and the moisture permeability of the film is increased, and the ability to protect the polarizer from humidity is reduced, which is not preferable.
- the optical film targeted by the present invention is a functional film used for various displays such as a liquid crystal display, a plasma display, and an organic EL display, particularly a liquid crystal display.
- a polarizing plate protective film, a retardation film, and an antireflection film in addition, it includes a retardation film, such as a brightness enhancement film, an optical compensation film for expanding the viewing angle, and the like.
- the polarizing plate including the retardation film constituted by the optical film of the present invention can exhibit high display quality as compared with a normal polarizing plate, particularly a multi-domain liquid crystal display device, more preferably birefringence. Suitable for use in multi-domain liquid crystal display devices by mode.
- Multi-domainization is also suitable for improving the symmetry of image display, and various methods have been reported “Okita, Yamauchi: Liquid Crystal, 6 (3), 303 (2002)”.
- the liquid crystal display cell is also shown in “Yamada, Yamabara: Liquid Crystal, 7 (2), 184 (2003)”, but is not limited thereto.
- the polarizing plate using the optical film of the present invention is an MVA (Multi-domain Vertical Alignment) mode typified by a vertical alignment mode, particularly a MVA mode divided into four, and a known PVA (Patterned) multi-domained by electrode arrangement. It can be effectively used for a Vertical Alignment (CPA) mode and a CPA (Continuous Pinsed Alignment Alignment) mode that combines electrode arrangement and chirality.
- CPA Vertical Alignment
- CPA Continuous Pinsed Alignment Alignment
- a proposal of an optically biaxial film is also disclosed in conformity with the OCB (Optical Compensated Bend) mode, and “T. Miyashita, T. Uchida: J. SID, 3 (1), 29 ( 1995) ”, a display quality effect can be exhibited by the polarizing plate using the optical film of the present invention.
- the arrangement of the liquid crystal mode and the polarizing plate is not limited.
- the display quality of the display cell is preferably symmetrical in human observation. Therefore, when the display cell is a liquid crystal display cell, it is possible to multiplex domains by giving priority to the symmetry on the observation side.
- a known method can be used to divide the domain, and can be determined in consideration of the properties of a known liquid crystal mode by a two-part dividing method, more preferably a four-part dividing method.
- Liquid crystal display devices are also being applied as devices for colorization and moving image display, and the display quality is improved by the optical film of the present invention, and the improvement in contrast and the resistance of the polarizing plate are improved. A moving image can be displayed.
- one polarizing plate including a retardation film constituted by the optical film of the present invention is arranged for the liquid crystal cell, or two polarizing plates are arranged on both sides of the liquid crystal cell. At this time, by using the retardation film side included in the polarizing plate so as to face the liquid crystal cell of the liquid crystal display device, the display quality can be improved.
- a polarizing plate protective film of a cellulose derivative is used on the surface opposite to the retardation film as viewed from the polarizer, and a general-purpose TAC film or the like can be used.
- the polarizing plate protective film located on the side far from the liquid crystal cell can be provided with another functional layer in order to improve the quality of the display device.
- the optical film according to the present invention may have functions such as antireflection, antiglare, abrasion resistance, dust adhesion prevention, and brightness enhancement. Although you may affix on the polarizing plate surface, it is not limited to these.
- functional layers such as an antistatic layer, a hard coat layer, a slippery layer, an adhesive layer, an antiglare layer, and a barrier layer may be coated before and / or after stretching.
- various surface treatments such as corona discharge treatment, plasma treatment, and chemical treatment can be performed as necessary.
- the method for producing the polarizing plate is not particularly limited, and can be produced by a general method.
- the obtained retardation film was alkali-treated, and a polarizer protective film was formed on both sides of the polarizer using a completely saponified polyvinyl alcohol aqueous solution on both sides of the polarizer prepared by immersing and stretching the polyvinyl alcohol film in an iodine solution.
- polarizing plate processing may be performed by applying an easy adhesion process as described in JP-A-6-94915 and JP-A-6-118232.
- the polarizing plate is composed of a polarizer and a protective film for protecting both surfaces of the polarizer, and further can be constructed by laminating a protective film on one surface of the polarizing plate and a separate film on the opposite surface.
- the protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection.
- the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate.
- a separate film is used in order to cover the contact bonding layer bonded to a liquid crystal board, and is used for the surface side which bonds a polarizing plate to a liquid crystal cell.
- Example 1 to 8 (Resin mixture) Cellulose acetate propionate 89% by mass (Acetyl group substitution degree 1.4, propionyl group substitution degree 1.35, Number average molecular weight 60000) 9% by mass of trimethylolpropane tribenzoate (Plasticizer, melting point 85 ° C) Antioxidant (IRGANOX XP 420 / FD) 0.25% by mass (Ciba Japan) UV absorber 1.6% by mass (TINUVIN 928, manufactured by Ciba Japan, melting point 115 ° C.) Matting agent (silica fine particles) 0.15% by mass (Seahoster KEP-30: Nippon Shokubai Co., Ltd., average particle size 0.3 ⁇ m) The degree of substitution of acyl groups such as acetyl group and propionyl group of cellulose acetate propionate was measured according to the method prescribed in ASTM-
- the above materials were mixed in a V-type mixer for 30 minutes, and then melted at 230 ° C. under a nitrogen atmosphere using a twin screw extruder equipped with a strand die to prepare cylindrical pellets having a length of 4 mm and a diameter of 3 mm. .
- the obtained pellet had a glass transition point (Tg) of 135 ° C. (Manufacture of optical films)
- Tg glass transition point
- the pellets were dried at 100 ° C. for 5 hours to have a water content of 100 ppm, and the pellets were supplied to the single screw extruder 1 equipped with the T die 4 shown in FIG.
- the melt contained 11% by mass of additives other than the resin.
- Nitrogen gas was sealed from the vicinity of the material supply port, and the inside of the extruder 1 was kept in a nitrogen atmosphere.
- the extruder 1 and the T die 4 were set to a temperature of 240 ° C.
- the T die 4 is a coat hanger type, has a width of 1500 mm, has an inner wall plated with hard chrome, and is finished to a mirror surface with a surface roughness of 0.1S.
- the lip gap of the T die 4 was set to 2 mm.
- the film-like melt from the T-die 4 is dropped onto a cast roll 5 having a mirror-plated mirror surface with a roll width of 1600 mm whose surface temperature is adjusted to 120 ° C., and the temperature is simultaneously raised to 120 ° C.
- the film was pressed by the adjusted touch roll (clamping rotary body) 6 having a roll width of 1600 mm.
- a releasability adjusting agent is applied in advance by a releasability adjusting agent coating apparatus 100 as shown in FIG. 1 upstream of the position of P2 in contact with the melt Y on the cast roll 5. Yes.
- the releasability adjusting agent coating apparatus 100 is heated to the same temperature 120 ° C. as the touch roll 6.
- an ultraviolet absorber TINUVIN 928 (T-928), dimethylsiloxane, and a tetrafluoroethylene copolymer were used.
- T-928 and dimethylsiloxane were applied in liquid form, and the tetrafluoroethylene copolymer was applied by dissolving 20 parts by mass with respect to 100 parts by mass of the solvent xylene.
- the tetrafluoroethylene copolymer was applied to the surface of the touch roll in the state of being divided into liquids.
- the coating thickness on the touch roll 6 was set as the manufacturing conditions of Examples 1 to 8 as shown in Table 1. Further, the contact angle between the surface of the cast roll 5 and water is 75 °, the contact angle between the surface of the touch roll 6 and the water after applying the releasability adjusting agent is 95 ° for T-928, and tetrafluoride.
- the ethylene copolymer was 109 ° and dimethylsiloxane was 120 °.
- the touch roll (clamping rotary body) 6 pressed the film with a linear pressure of 5 N / mm.
- the cast roll 5 is made of stainless steel, and the surface roughness is 0.1 ⁇ m or less at the maximum height Ry.
- the touch roll 6 is a double cylinder structure having a metal outer cylinder, an inner cylinder, and a gap.
- the material of the metal outer cylinder was stainless steel, the surface roughness was 0.05 ⁇ m or less at the maximum height Ry, and the wall thickness was 3 mm.
- the inner cylinder was aluminum and the wall thickness was 30 mm.
- the gap between the metal outer cylinder and the inner cylinder was 5 mm. Oil was allowed to flow through the gap 47, and the temperature of the surface of the metal outer cylinder was set to 120 ° C.
- the film pressed by the cast roll 5 and the touch roll (clamping rotating body) 6 is successively circumscribed on the cooling roll 7 and the roll of the cooling roll 8 in order to cool and solidify, and is peeled off by the peeling roll 9.
- the conveyance speed of the film was 10 m / min.
- the unstretched film 17 after the clamping was stretched 2.0 times in the longitudinal direction.
- the stretching ratio at the time of transverse stretching was 2.0 times that was transversely stretched using a tenter apparatus as the transverse stretching apparatus 20.
- the stretched film was slit with a slitter so as to have a width of 1300, and then wound with a winder 60 to produce optical films of Examples 1 to 8 having a width of 1300 mm, a film thickness of 100 ⁇ m, and a length of 1000 m.
- the surface of the entire area of the optical film was visually observed for the presence or absence of stripe-like unevenness (lateral unevenness) in the film width direction. Those having no horizontal unevenness were ranked as rank 4, those having 1 or more and less than 3 were ranked 3, those having 3 or more and less than 6 were ranked 2, and those having 6 or more were ranked 1.
- the films of Examples 1 to 8 were sandwiched between two polarizers arranged in a crossed Nicol state, that is, in an orthogonal state (crossed Nicol state) with a polarizing plate, and one polarizing plate Light was applied from the outside of the film and visually observed from the outside of the other polarizing plate to rank the retardation uniformity.
- Rank A is a dark field with no light transmission over the entire area of the optical film
- rank B is a part with a slight stripe-like light and darkness.
- Rank C was rated for light and darkness
- Rank D was rated for partially streaky light and darkness.
- Example 2 In the manufacturing method of the optical film of Example 1, the release agent used in Example 1 was applied to the surface of the cast roll 5 before dropping the film-like melt without applying the release property adjusting agent to the surface of the touch roll 6. This was prepared and evaluated in the same manner as in Example 1 except that the property modifier (T-928) was applied to a thickness of 0.04 ⁇ m.
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Abstract
Description
前記流延工程で押し出されたフィルム状の溶融物を、前記回転支持体と挟圧回転体とで挟圧する挟圧工程とを備えた光学フィルムの製造方法において、
前記挟圧回転体の表面に、前記挟圧回転体と前記フィルム状の溶融物との離型性を良くするための離型性調整剤を塗布することを特徴とする光学フィルムの製造方法。
(液晶表示装置)
本発明の光学フィルムによって構成される位相差フィルムを含む偏光板は、通常の偏光板と比較して高い表示品質を発現させることができ、特にマルチドメイン型の液晶表示装置、より好ましくは複屈折モードによるマルチドメイン型の液晶表示装置への使用に適している。
(実施例1~8)
(樹脂混合物)
セルロースアセテートプロピオネート 89質量%
(アセチル基置換度1.4、プロピオニル基置換度1.35、
数平均分子量60000)
トリメチロールプロパントリベンゾエート 9質量%
(可塑剤、融点85℃)
酸化防止剤(IRGANOX XP 420/FD) 0.25質量%
(チバ・ジャパン社製)
紫外線吸収剤 1.6質量%
(TINUVIN 928、チバ・ジャパン社製、融点115℃)
マット剤(シリカ微粒子) 0.15質量%
(シーホスターKEP-30:日本触媒株式会社製、平均粒径0.3μm)
なお、セルロースアセテートプロピオネートのアセチル基、プロピオニル基等のアシル基の置換度の測定は、ASTM-D817-96に規定の方法に準じて測定した。
(光学フィルムの製造)
上記ペレットを100℃で5時間乾燥させ、含水率100ppmとし、図2に示すTダイ4を取り付けた単軸押出し機1に該ペレットを供給して製膜を行った。溶融物には、樹脂以外の添加剤が11質量%含まれていた。
(光学フィルムの評価)
つぎに、実施例1~8の光学フィルムについて、光学フィルムの全領域の表面を目視観察により、フィルム幅方向の筋状のムラ(横段ムラ)の有無を観察した。横段ムラの無いものをランク4、1本以上3本未満のものをランク3、3本以上6本未満のものをランク2、6本以上あるものをランク1とした。また、リタデーションの均一性の評価として、実施例1~8のフィルムを、偏光板によるクロスニコル下、すなわち、直交状態(クロスニコル状態)に配置した2枚の偏光子で挟み、一方の偏光板の外側から光を当て、他方の偏光板の外側から目視で観察し、リタデーションの均一性のランク付けをした。光学フィルムの全領域に渡って、光の透過がなく、全体に均一な暗視野のものをランクA、部分的にスジ状の明暗がわずかに認められるものをランクB、部分的にスジ状の明暗が認められるものをランクC、部分的に強いスジ状の明暗が認められるものをランクDとした。横段ムラが目視により6本以上観察され、リタデーションのムラがランクDでは、製品品質上問題となる。
(比較例1)
実施例1の光学フィルムの製造方法において、タッチロール6の表面に離型性調整剤を塗布しなかった他は、実施例1と同様に作製し、評価した。
(比較例2)
実施例1の光学フィルムの製造方法において、タッチロール6の表面に離型性調整剤を塗布せず、フィルム状溶融物を落下させる前のキャストロール5の表面に実施例1で用いた離型性調整剤(T-928)を0.04μmの厚さに塗布した他は、実施例1と同様に作製し、評価した。
2 フィルター
3 スタチックミキサー
4 流延ダイ
5 キャストロール、回転支持体
6 タッチロール、挟圧回転体
7、8 冷却ロール
P1 フィルムが最初にキャストロール表面に接触した点
P2 フィルムがタッチロール表面に接触した点
P3 フィルムがキャストロールから離れる点
9 剥離ロール
10 縦延伸装置
17 フィルム
19 スリッター
20 横延伸装置
52 バックロール
53 エンボスリング
60 巻取り装置
100 離型性調整剤塗布装置
101 塗布ローラ
102 汲み上げローラ
103 規制ブレード
104 離型性調整剤
105 貯留槽
Y 溶融物
F 光学フィルム(元巻き)
Claims (10)
- 熱可塑性樹脂を含む溶融物を流延ダイから回転支持体の表面にフィルム状に押し出す流延工程と、
前記流延工程で押し出されたフィルム状の溶融物を、前記回転支持体と挟圧回転体とで挟圧する挟圧工程とを備えた光学フィルムの製造方法において、
前記挟圧回転体の表面に、前記挟圧回転体と前記フィルム状の溶融物との離型性を良くするための離型性調整剤を塗布することを特徴とする光学フィルムの製造方法。 - 前記離型性調整剤が、前記溶融物に含まれる添加剤のうち少なくとも1つと同じ材料を含むことを特徴とする請求項1に記載の光学フィルムの製造方法。
- 前記離型性調整剤が、前記光学フィルムの内部で紫外線を吸収するために用いられる紫外線吸収剤であることを特徴とする請求項1又は2に記載の光学フィルムの製造方法。
- 前記離型性調整剤の沸点が、150~250℃であることを特徴とする請求項1から3の何れか1項に記載の光学フィルムの製造方法。
- 前記離型性調整剤を塗布する厚みが、0.05~1000μmであることを特徴とする請求項1から4の何れか1項に記載の光学フィルムの製造方法。
- 前記回転支持体の表面と水との接触角S1と、前記離型性調整剤を塗布した後の挟圧回転体の表面と水との接触角S2とが、0.5°<S2-S1<100°の関係にあることを特徴とする請求項1から5の何れか1項に記載の光学フィルムの製造方法。
- 前記挟圧回転体が前記回転支持体に押圧した状態での前記フィルム状の溶融物の搬送張力T1と、前記挟圧回転体が前記回転支持体に押圧していない状態での前記フィルム状の溶融物の搬送張力T2との差T1-T2が、1~250Nであることを特徴とする請求項1から6の何れか1項に記載の光学フィルムの製造方法。
- 前記熱可塑性樹脂が、セルロースエステル系樹脂であることを特徴とする請求項1から7の何れか1項に記載の光学フィルムの製造方法。
- 請求項1から8の何れか1項に記載の光学フィルムの製造方法により製造したことを特徴とする光学フィルム。
- 熱可塑性樹脂を含む溶融物を回転支持体の表面にフィルム状に押し出す流延ダイと、前記流延ダイで押し出されたフィルム状の溶融物を、前記回転支持体と挟圧回転体とで挟圧する挟圧手段とを備えた光学フィルムの製造装置において、前記挟圧回転体の表面に、前記挟圧回転体と前記フィルム状の溶融物との離型性を良くするための離型性調整剤を塗布する離型性調整剤塗布装置を有することを特徴とする光学フィルムの製造装置。
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JP2014517850A (ja) * | 2011-04-08 | 2014-07-24 | イノヴィア フィルムズ リミテッド | 生分解性フィルム |
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JPH08336878A (ja) * | 1995-06-13 | 1996-12-24 | Denki Kagaku Kogyo Kk | 樹脂シートの製造方法 |
WO2000066339A1 (fr) * | 1999-04-30 | 2000-11-09 | Kyowa Hakko Kogyo Co., Ltd. | Procede et dispositif de production d'un article en resine moule |
JP2006305924A (ja) * | 2005-04-28 | 2006-11-09 | Nippon Synthetic Chem Ind Co Ltd:The | ポリビニルアルコール系フィルムの製造方法、およびポリビニルアルコール系フィルム |
JP2007313888A (ja) * | 2006-04-28 | 2007-12-06 | Konica Minolta Opto Inc | 凹凸構造が設けられた光学フィルムの製造方法、光学フィルム、ワイヤグリッド偏光子、及び位相差フィルム |
JP2008044336A (ja) * | 2006-07-20 | 2008-02-28 | Konica Minolta Opto Inc | タッチロール、光学フィルムの製造装置、及び、光学フィルムの製造方法 |
JP2008080552A (ja) * | 2006-09-26 | 2008-04-10 | Konica Minolta Opto Inc | 光学フィルムの製造装置 |
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JP2005172940A (ja) | 2003-12-08 | 2005-06-30 | Sekisui Chem Co Ltd | 光学フィルム及びその製造方法 |
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Patent Citations (6)
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JPH08336878A (ja) * | 1995-06-13 | 1996-12-24 | Denki Kagaku Kogyo Kk | 樹脂シートの製造方法 |
WO2000066339A1 (fr) * | 1999-04-30 | 2000-11-09 | Kyowa Hakko Kogyo Co., Ltd. | Procede et dispositif de production d'un article en resine moule |
JP2006305924A (ja) * | 2005-04-28 | 2006-11-09 | Nippon Synthetic Chem Ind Co Ltd:The | ポリビニルアルコール系フィルムの製造方法、およびポリビニルアルコール系フィルム |
JP2007313888A (ja) * | 2006-04-28 | 2007-12-06 | Konica Minolta Opto Inc | 凹凸構造が設けられた光学フィルムの製造方法、光学フィルム、ワイヤグリッド偏光子、及び位相差フィルム |
JP2008044336A (ja) * | 2006-07-20 | 2008-02-28 | Konica Minolta Opto Inc | タッチロール、光学フィルムの製造装置、及び、光学フィルムの製造方法 |
JP2008080552A (ja) * | 2006-09-26 | 2008-04-10 | Konica Minolta Opto Inc | 光学フィルムの製造装置 |
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JP2014517850A (ja) * | 2011-04-08 | 2014-07-24 | イノヴィア フィルムズ リミテッド | 生分解性フィルム |
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