Abstract: One embodiment of the present invention provides a method for producing a stretched cellulose acylate film with an in-plane retardation, Re, of 100 nm or more and a relationship between the thickness direction retardation, Rth, and Re which satisfies Rth<(Re/2), by longitudinally stretching an unstretched cellulose acylate film in a longitudinal direction by pulling by means of a difference in circumferential velocity between a pair of rollers, wherein the method is characterized in that the cellulose acylate film is subjected to free-end uniaxial stretching to a longitudinal stretch ratio of 1 to 2 while the film is being heated in a heating oven installed between the pair of rollers at a stretching temperature in the range of Tc?10° C. to Tc+70° C., Tc being the crystallization temperature of the film, and with the temperature difference in the film width direction maintained within 10° C.

Abstract: A thermoplastic film is transversely stretched, and then transported in a heat-treating zone (46) such that the ratio (G/D) of an inter-roll distance (G) to a roll lap length (D) is 0.01 to 3, and the ratio (V2/V1) of an exit-side transporting speed (V2) to an entry-side transporting speed (V1) is 0.6 to 0.999. The thermoplastic film is heat-treated in the heat-treating zone (46) at (Tg?20)° C. to (Tg+50)° C., in which Tg is the glass transition temperature of the film. The heat-treated thermoplastic film exhibits an Rth/Re ratio of at least 0.5 and less than 1, an Rth/Re ratio range of 0.01 to 0.1 in the width direction, and a thermal dimensional change of 0.001% to 0.3% under conditions of 80° C. and 200 hours.

Abstract: The present invention provides a method for producing a cellulose acylate resin film, comprising the step of, melting a cellulose acylate resin in an extruder and extruding the molten cellulose acylate resin to a die, wherein the step of melting is carried out using a tandem extruder having a first-stage extruder and a second-stage extruder connected in tandem, in order to prevent discoloration and thickness non-uniformity make the film seriously defective for use as an optical film. Because the resin in the form of a powder or flakes is once pelletized in a pelletizing extruder, and then the pellets are melt-extruded in an extruder. This promotes discoloration of the resin, disadvantageously.

Abstract: Provided is a cellulose acylate film formed through melt casting that is capable of being built in liquid-crystal display devices to solve the display trouble at the time of black level of display. That is a cellulose acylate film formed through melt casting, in which the number of polarizing minor impurities is from 0 to 10/mm2 and the number of black impurities is from 0 to 10/mm2, and which has a transmittance at 450 nm (T450) of from 90 to 100%.

Abstract: Disclosed is a cellulose acylate film produced according to a melt casting process and having an Re unevenness of from 0 to 10%. When built in a liquid-crystal display device, the film significantly solves the problem of display unevenness and humidity-dependent visibility change.

Abstract: An unstretched cellulose acylate film hardly breakable upon stretching can be produced by melt film forming and as a result, a highly oriented stretched cellulose acylate film can be obtained. Using an extruder with a screw compression ratio of 2.5 to 4.5 and an L/D of 20 to 50, a cellulose acylate resin is extruded into a sheet at an extrusion temperature of 190° C. to 240° C. from a die to a cooling drum, and solidified by cooling to prepare an unstretched cellulose acylate film 16, which is then stretched to produce a stretched cellulose acylate film.

Abstract: According to the present invention, a cellulose acylate film having high thickness precision and no streaks can be formed by producing a film with a cellulose acylate resin by means of the polishing roller method, and a high-performance optical film, which is free from the retardation distribution, can be produced by subsequently stretching the cellulose acylate film thus obtained within a magnification range from 1 or more and 2.5 or less.

Abstract: According to the present invention, a cellulose acylate film difficult to be broken even if the stretching ratio is increased upon stretching and whose retardation (Re) is easily controllable to a desired value can be produced by melt film forming. Accordingly, a stretched cellulose acylate film highly oriented and having an appropriate retardation (Re) required from liquid crystal display device manufacturers can be produced.

Abstract: A cellulose acylate film showing 10 marks/m2 or less of adhesion marks and having an in-plane retardation value (Re value) of 0 to 200 nm and a retardation value along the thickness direction (Rth value) of 30 to 500 nm. The cellulose acylate film shows favorable optical uniformity and can provide an improved liquid crystal display.

Abstract: One embodiment of the present invention provides a method for producing a stretched cellulose acylate film with an in-plane retardation, Re, of 100 nm or more and a relationship between the thickness direction retardation, Rth, and Re which satisfies Rth<(Re/2), by longitudinally stretching an unstretched cellulose acylate film in a longitudinal direction by pulling by means of a difference in circumferential velocity between a pair of rollers, wherein the method is characterized in that the cellulose acylate film is subjected to free-end uniaxial stretching to a longitudinal stretch ratio of 1 to 2 while the film is being heated in a heating oven installed between the pair of rollers at a stretching temperature in the range of Tc?10° C. to Tc+70° C., Tc being the crystallization temperature of the film, and with the temperature difference in the film width direction maintained within 10° C.

Abstract: There is provided a method for producing a thermoplastic film, which can suppress the occurrence of residual strain in the film caused by the polishing roller method to prevent the occurrence of stretch non-uniformity in stretching operation and provide a film that has excellent optical characteristics. The molten resin extruded from a die into a sheet is fed between a pair of polishing rollers and cooled while being held and pressed between them so that a cellulose acylate film is formed. The surface of the polishing roller is made up of a fluorine resin.

Abstract: In the method for producing a bi-axially oriented thermoplastic resin film, the longitudinal draw ratio X in a longitudinal drawing step is in the range of from 2.8 times to 3.5 times, and the transverse draw ratio Y in a transverse drawing step is in the range of from 3.8 times to 4.8 times. The expression: X?0.25Y+2.0+(T?(Tg+50))/400, is satisfied where T° C. represents the temperature of the thermoplastic resin film in the transverse drawing step in a tenter 28 and Tg° C. represents the glass transition temperature of the thermoplastic resin film.

Abstract: Electromagnetic waves radiated when a formed polyester film 18 is longitudinally drawn while one surface of the front and rear surfaces of the polyester film 18 is being heated by a radiant heater 30, are composed of such a wavelength band that a thermal energy of 20% or more and 50% or less of the total thermal energy radiated onto the one surface of the polyester film 18 can transmit from the one surface to the other surface. Thereby, even in the case where the film is longitudinally drawn while one surface of the film is being heated in the longitudinal drawing step, a curl is not easily generated in the film.

Abstract: A method is provided for manufacturing a wide band retardation plate which gives uniform phase difference characteristics to incident light over the whole visible wavelength region, and which, as it permits selection of raw materials regardless of whether they have a positive or negative intrinsic double refraction value, allows a wide selection of raw materials.

Abstract: A method for producing a polyester resin film includes melt extruding a polyester resin into a sheet shape, cooling and solidifying the polyester resin sheet on a casting drum, then longitudinally stretching the polyester resin sheet in the longitudinal direction, and then transversely stretching the longitudinally stretched polyester resin film in the transverse direction. The glass transition temperature of the polyester resin, Tg (° C.), the crystallinity of the film after the longitudinal stretching, Xc (%), the crystallization temperature of the film after the longitudinal stretching, Tc (° C.), film surface temperature at the entrance of the stretching zone of a transverse stretching apparatus 30, Ts (° C.), and film surface temperature at the exit of the stretching zone of the transverse stretching apparatus 30, Te (° C.), satisfy: 3?Xc?20; Tg?10?Ts?Tc+20; and Tc?10?Te?Tc+80.

Abstract: One aspect of the present invention provides a method for production of a polyester resin film comprising melt extruding a polyester resin into a sheet shape, cooling and solidifying the polyester resin sheet on a casting drum, then longitudinally stretching the polyester resin sheet in a longitudinal direction, and then passing the longitudinally stretched polyester resin film through a transverse stretching apparatus to transversely stretch the longitudinally stretched polyester resin film in a transverse direction, wherein Xc, Tc, Ts and Te satisfy the formulas of: Tc?(Ts+Te)/2+2.66Xc?Tc+60??(1) and 2?Xc?30??(2), in which Xc (%) indicates a crystallinity of the film after the longitudinal stretching, Tc (° C.) indicates a crystallization temperature of the film after the longitudinal stretching, Ts (° C.) indicates a film surface temperature at an entrance of a stretching zone of the transverse stretching apparatus, and Te (° C.

Abstract: According to the present invention, the adaptability to producing the cellulose acylate film and the surface properties of the cellulose acylate film produced by means of the melt film-forming method can be remarkably improved. Accordingly, there is also improved the surface properties of a stretched cellulose acylate film produced by stretching such an unstretched cellulose acylate film.

Abstract: According to the present invention, a cellulose acylate film having high thickness precision and no streaks can be formed by producing a film with a cellulose acylate resin by means of the polishing roller method, and a high-performance optical film, which is free from the retardation distribution, can be produced by subsequently stretching the cellulose acylate film thus obtained within a magnification range from 1 or more and 2.5 or less.

Abstract: An unstretched cellulose acylate film is stretched in a ratio ranging from 1.05 to 1.6 in the longitudinal direction (MD) in a longitudinal stretching section using at least two rollers having a surface-to-surface separation of 2 to 50 mm therebetween and being different in circumferential velocity, thereafter the cellulose acylate film stretched in the longitudinal direction is heated in the heat treatment section to a temperature ranging from Tc to Tc+80° C. under the conditions that the widthwise ends of the cellulose acylate film are gripped, and thus the cellulose acylate film is contracted in the widthwise direction (TD) to produce the intended cellulose acylate film. This method can provide a cellulose acylate film having properties suitable for an optical film and so on.

Abstract: The present invention provides a method for producing a cellulose acylate film which can prevent the generation of foreign matter problems and can produce a high-quality film. A cellulose acylate resin is molten in a twin-screw extruder and extruded from a die to form a cellulose acylate film. The average residence time of the resin in the extruder is set at 5 minutes or less.