Abstract: A method for producing a carbon material, the method including a step of performing a carbonization treatment by heating an organic polymer material to a temperature higher than 400° C. in a non-oxidizing atmosphere containing a gaseous substance (A) composed of at least one of acetylene and an acetylene derivative.

Abstract: A high-quality flame-resistant fiber and carbon fiber at low costs in preparing a flame-resistant fiber and a carbon fiber by efficiently performing a flame retardation process in a short time as compared with a conventional technology are described. [1] If a polyacrylonitrile (PAN) polymer is degenerated with an oxidizing agent containing a thiolate compound and a nitrogen atom in a polymer, and the degenerated polymer is formed into threads so as to prepare a flame-resistant PAN fiber. [2] A flame-resistant PAN fiber is prepared by degenerating a PAN precursor fiber in a solution including a thiolate compound and an oxidizing agent containing a nitrogen atom. The flame-resistant PAN fiber obtained by the preparation method is heated at 300° C. or more to 3000° C. or less, and, thus, a carbon fiber having an excellent mechanical strength can be obtained.

Abstract: A method for producing a carbon material, the method including a step of performing a carbonization treatment by heating an organic polymer material to a temperature higher than 400° C. in a non-oxidizing atmosphere containing a gaseous substance (A) composed of at least one of acetylene and an acetylene derivative.

Abstract: A high-quality flame-resistant fiber and carbon fiber at low costs in preparing a flame-resistant fiber and a carbon fiber by efficiently performing a flame retardation process in a short time as compared with a conventional technology are described. [1] If a polyacrylonitrile (PAN) polymer is degenerated with an oxidizing agent containing a thiolate compound and a nitrogen atom in a polymer, and the degenerated polymer is formed into threads so as to prepare a flame-resistant PAN fiber. [2] A flame-resistant PAN fiber is prepared by degenerating a PAN precursor fiber in a solution including a thiolate compound and an oxidizing agent containing a nitrogen atom. The flame-resistant PAN fiber obtained by the preparation method is heated at 300° C. or more to 3000° C. or less, and, thus, a carbon fiber having an excellent mechanical strength can be obtained.

Abstract: The invention provides a method for producing carbon fiber bundles excellent in productivity without impairing the quality in the process for producing carbon fibers. The method includes a flame-retarding step, a precarbonization step, and a carbonization step. When traveling pitches of the fiber bundles in the flame-retarding step, precarbonization step and carbonization step are represented by P1, P2 and P3, respectively, 0.8?P2/P1?1.0 and 0.4?P3/P1?0.8 are satisfied; when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a precarbonization furnace are represented by P11 and P12, respectively, 0.40?(P12/P11)?0.90 is satisfied; or when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a carbonization furnace are represented by P13 and P14, 0.40?(P14/P13)?0.90 is satisfied.

Abstract: A process for producing a flame-resistant fiber bundle, the process comprising a step in which a flame-resistant fiber bundle (1) having a single-fiber density ?F1 of 1.26 g/cm3 to 1.36 g/cm3 is brought into contact sequentially with a heater group having a surface temperature TH of 240° C. to 400° C. under the following conditions (A), (B), and (C) to obtain a flame-resistant fiber bundle (2) having a single-fiber density ?F2 of 1.33 g/cm3 to 1.43 g/cm3: (A) the heater Hn+1 with which the fiber bundle is brought into contact “n+1”-thly has a highter temperature than the heater Hn with which the fiber bundle is brought into contact “n”-thly; (B) the total contact time between the fiber bundle and the heater group is 10 seconds to 360 seconds; and (C) the contact time between the fiber bundle and each heater is 2 seconds to 20 seconds.

Abstract: The invention provides a method for producing carbon fiber bundles excellent in productivity without impairing the quality in the process for producing carbon fibers. The method includes a flame-retarding step, a precarbonization step, and a carbonization step. When traveling pitches of the fiber bundles in the flame-retarding step, precarbonization step and carbonization step are represented by P1, P2 and P3, respectively, 0.8?P2/P1?1.0 and 0.4?P3/P1?0.8 are satisfied; when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a precarbonization furnace are represented by P11 and P12, respectively, 0.40?(P12/P11)?0.90 is satisfied; or when traveling pitches of the fiber bundles at the inlet and the outlet of a heat treatment section of a carbonization furnace are represented by P13 and P14, 0.40?(P14/P13)?0.90 is satisfied.

Abstract: The object of the present invention is to provide a laminate for laser marking which is useful for forming displays or indications, for example, on the surface of sheet-like molded products made of thermoplastic resins, by suitably employing thermoplastic polymer resins for laser marking, and whose slipping property on the production process can be improved and whose blocking problem at the storage in the stacked condition can be solved. In an aspect of the present invention, there is provided a laminate for laser marking comprising a layer (A) and a layer (B) laminated on at least one side of layer (A), which layer (A) comprises a white or black coloring laser-marking thermoplastic resin, which layer (B) comprises a transparent thermoplastic resin and has a light transmittance of not less than 70% in the single layer, and the transparent thermoplastic resin in the layer (B) being subjected to anti-blocking treatment.

Abstract: There is provided a laminate for laser marking which is useful for forming displays, for example, on the S-shaped surface of sheet-like molded products made of thermoplastic resins, by suitably employing a thermoplastic polymer composition for laser marking. The present invention relates to a laminate for laser marking, comprising: a layer A comprising a multi-color developing laser marking thermoplastic polymer composition capable of producing markings having two or more different color tones by irradiating thereto two or more laser lights having different energies from each other, the composition satisfying the following requirements (1) and (2): (1) comprising a chromatic colorant, a black substance capable of being dissipated by itself or discolored when exposed to the laser lights, and a thermoplastic polymer at the following mixing ratio, and (2) containing the chromatic colorant and the black substance in amounts of from 0.001 to 3 parts by weight and from 0.

Abstract: A biaxially oriented polyester film for a magnetic recording medium contains: 1) at least two different sizes of synthetic calcium carbonate particles; and 2) aluminum oxide particles to produce a film with excellent surface uniformity, running properties, and slittability wherein the film generates few scratches and low amounts of abrasion dust. The synthetic calcium carbonate particles are surface treated with a polycarboxylic acid, followed by treatment with a phosphorus compound. The biaxially oriented polyester film can comprise a layer in a multilayer film.

Abstract: A biaxially oriented laminated polyester film for magnetic recording media, which has excellent surface uniformity, slittability, running property and cost performance, and in which a magnetic tape produced therefrom shows a very small number of scratches and a very small amount of abrasion dust.

Abstract: A laminated polyester film for a magnetic recording medium having at least three layers, in which each of a top layer and a bottom layer of the at least three layers contains inorganic particles having a Moh's hardness of at least 8 and an average particle size of 0.005 to 0.5 .mu.m in an amount of 0.25 to 5% by weight based on the weight of the polyester of the respective layer and, in total, not larger than 0.20% by weight based on the whole weight of the polyesters of all the layers including an intermediate layer, and exposed surfaces of the top and bottom layers have coefficients of friction and surface roughness which satisfy the specific conditions.

Abstract: A laminated polyester film for a magnetic recording medium which has a first polyester layer (A) containing inorganic particles (a) having a Moh's hardness of at least 8 and a specific average particle size and inactive particles (b) having a Moh's hardness of less than 8 and a specific average particle size larger than that of the particle (a) and a second polyester layer (B) containing inactive particles (c) having a Moh's hardness of less than 8 and a specific average particle size, wherein a content of the particles (a) is from 0.25 to 5% by weight based on the weight of the polyester in the layer (A) and less than 0.15% by weight of the whole weight of the polyester in the layers (A) and (B), the contents of the particles (b) and (c) are each 0.05 to 2.0% by weight of the polyester in the layers (A) and (B), respectively, and exposed surfaces of the layers (A) and (B) have coefficients of friction and surface roughness (Ra) which satisfy the specific conditions.

Abstract: A biaxially oriented polyester film simultaneously satisfying the following formulas (I) to (III):.vertline.S.sub.180 -S.sub.120 .vertline..ltoreq.54 (I)T.sub.S.sup.MD .gtoreq.100 (II)Q.sub.120 .ltoreq.0.7 (III)wherein S.sub.180 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 180.degree. C., S.sub.120 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 120.degree. C., T.sub.S.sup.MD is shrinkage initiation temperature (.degree.C.) of the film in the machine direction, and Q.sub.120 is shrinkage (%) of the film in the machine direction after 5 hours' treatment at 120.degree. C., is described. The film has a good dimensional stability due to its low shrinkage, particularly in the machine direction, and substantially free from defect such as wave and wrinkle.It is prepared by biaxially stretching, heat-setting and relaxing an extruded polyester film under particular conditions so as to obtain a biaxially oriented polyester film having these characteristics.

Abstract: Disclosed herein is a moldable biaxially stretched polyester film having a tensile strength at 100% elongation (F.sub.100), measured in an atmosphere of 150.degree. C., of 0.5 to 7 kg/mm.sup.2.The biaxially stretched polyester film according to the present invention is excellent in moldability.

Abstract: A polyester film suitable for a base of high density magnetic recording medium containing barium ferrite as a magnetic material characterized in that the centerline average roughness (Ra) is not more than 0.025 .mu.m and the F.sub.5 value in the longitudinal direction is not less than 14 kg/mm.sup.2 is disclosed wherein the polyester film exhibit excellent better durability when used with barium ferrite as a magnetic material.

Abstract: A biaxially stretched polyester film which satisfies the following equations (1) to (4):0.155 . .ltoreq..DELTA.P .ltoreq.0.180 (1)1.6050 ..ltoreq.n..ltoreq.1.6085 (2)n .gtoreq.1.622-(0.1.times..DELTA.P) (3).sup..alpha. MD+TD ..ltoreq.3.0 (4)wherein .DELTA.P, n and .sup..alpha. MD+TD respectively respect the degree of surface orientation, the average refractive index and the sum (%) of the shrinkage in the machine and transverse directions after the film is subjected to heat treatment at 105.degree. C. for 30 minutes. The film is not easily curled even if one side thereof is treated with a solvent, and is thus suitable for use involving a step of dipping one surface of a film in a solvent, such as solvent development-type photo resist film and base films for magnetic recording media.

Abstract: The polyester film according to the present invention is produced by molding a composition comprising an aromatic polyester, 3 to 40 wt %, based on the amount of said polyester, of a crystalline polypropylene having a melt flow index of 0.2 to 120, and 0.001 to 3 wt %, based of the total amount of said polyester and said polypropylene, of a surface-active agent into a sheet; and stretching the thus obtained sheet at least one direction. The polyester film according to the present invention, which is obtained by the above process is low in the apparent specific gravity because of a large number of minute closed cells contained therein. Further, the polyester film according to the present invention shows a high opacifying power by adding a small amount of titanium oxide or without adding the titanium oxide, which have been added in a large amount. The polyester film can be used as the materials for printing plates and substrates in data devices.

Abstract: A film is disclosed, which comprises an at least uniaxially stretched finely cellulated polyester film of a high surface roughness having an apparent specific gravity in the range of 0.4 to 1.3 and an opacifying power of not less than 0.2, and a coating applied to either or both of the opposite surfaces of the polyester film.The coating applied to the minute-cellular polyester film serves the purpose of improving the adhesive property of the polyester film.

Abstract: A biaxially oriented polyester film simultaneously satisfying the following formulas (I) to (III):.vertline.S.sub.180 -S.sub.120 .vertline..ltoreq.54 (I)T.sub.S.sup.MD .gtoreq.100 (II)Q.sub.120 .ltoreq.0.7 (III)wherein S.sub.180 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 180.degree. C., S.sub.120 is shrinking stress (g/mm.sup.2) of the film in the machine direction at 120.degree. C., T.sub.S.sup.MD is shrinkage initiation temperature (.degree.C.) of the film in the machine direction, and Q.sub.120 is shrinkage (%) of the film in the machine direction after 5 hours' treatment at 120.degree. C., is described. The film has a good dimensional stability due to its low shrinkage, particularly in the machine direction, and substantially free from defect such as wave and wrinkle.It is prepared by biaxially stretching, heat-setting and relaxing an extruded polyester film under particular conditions so as to obtain a biaxially oriented polyester film having these characteristics.