Abstract: A heat-resistant film or sheet produced by melt extruding polyether ketone having an intrinsic viscosity of at least 0.4 dl/g, which is obtained by heat treating an unstretched film or sheet which comprises (i) heat-treating to crystallization being not more than 60%, or (ii) uni- or biaxially stretching under specific conditions to an extent in which a stress at 5% elongation in the stretched direction is at least 13 kg/mm.sup.2 ; an initial elastic modulus in the stretched direction is at least 600 kg/mm.sup.2 ; and thermal shrinkages in a lengthwise direction and its vertical direction are not more than 4%.The film or sheet of the present invention is excellent in such properties as heat resistance, mechanical strength and the like, and is suitable for use as a substrate for magnetic recording or electric insulation.

Abstract: A biaxially oriented polyester film for floppy disks which has an in-plane thermal expansion coefficient (.alpha..sub..gamma.) of (1.7.+-.0.8).times.10.sup.-5 /.degree.C. and a shrinkage of not more than 0.03% after 72-hour treatment under the conditions of 60.degree. C. and 80% RH, and which simultaneously satisfies the following relationships (1) to (6):1.492.ltoreq.n.alpha..ltoreq.1.505 (1)0.160.ltoreq..DELTA.P.ltoreq.0.168 (2)1.605.ltoreq.n.ltoreq.1.609 (3)5.ltoreq.X.sub.I .ltoreq.15 (4)60.ltoreq.X.sub.100 .ltoreq.68 (5)1.395.ltoreq..rho..ltoreq.1.405 (6)wherein n.alpha. represents the refractive index of the film in the direction of the thickness, .DELTA.P the degree of planar orientation, n the average refractive index, X.sub.I the X-ray diffraction peak ratio, X.sub.100 the crystal size (A) in the (100) face, and .rho. the density.

Abstract: Disclosed herein is a uniaxially or biaxially oriented polyphenylene sulfide film wherein the number of n-order of interference fringes Hn (per mm.sup.2) as measured by a multiple interference method satisfies the following relations (1) and (2) at the same time:30.ltoreq.H.sub.1 .ltoreq.300 (1)10.ltoreq.H.sub.3 .ltoreq.

Abstract: Disclosed herein is a polyethylene naphthalate film for high-density magnetic recording media of floppy disk which has little anisotropy, high mechanical strength and good dimensional stability, and which scarcely causes a drop out and has good productivity.

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: Disclosed herein is a biaxially oriented polyester film for magnetic recording media, containing uniformly carbon black particles and having the following specific properties: ##EQU1## wherein T.sub.900 represents a light transmittance of the film at a wavelength of 900 nm, Ra represents an average surface roughness of the film n.sub.1 represents the number of protuberances of 0.81 to 1.08 .mu.m in height existing on the surface of the film per film area of 25 cm.sup.2, and n.sub.2 represents the number of protuberances of more than 1.08 .mu.m in height existing on the surface of the film per film area of 25 cm.sup.2.

Abstract: A polyester film suitable for use as the magnetic tape base for video recording, capable of high density recording and having stable slidability or running characteristics. The polyester film is made of a polyester which contains 0.05-1 wt % particles containing calcium and phosphorus and of which the number n of the second interference fringes (number/mm.sup.2) and the average centerline roughness (.mu.m) satisfy the following relationships:n<30 (1)0.005.ltoreq.R.sub.a .ltoreq.0.

Abstract: A polyethylene-2,6-naphthalate film for capacitors and, in particular, a polyethylene-2,6-naphthalate film which is excellent in heat resistance and mechanical strength and is useful for the dielectric of a chip type plastic film capacitor which requires a very thin film.

Abstract: A shrinkable film for packaging excellent in the heat-sealing property and the shrinking property is disclosed. This shrinkable film is obtained by stretching a film of a mixture comprising 100 to 30 weight parts of a crystalline polyester (A), which comprises mainly terephthalic acid and 1,4-cyclohexane dimethanol and has a heat of crystalline melting of not less than 3 cal/g and a melting point in the range of 200.degree. to 310.degree. C., and 0 to 70 weight parts of a polyester (B) comprising terephthalic acid and/or 2,6-naphthalene dicarboxylic acid as the dicarboxylic acid constitutional unit and ethylene glycol and/or 1,4-butylene glycol as the glycol constitutional unit. The mixture of the polyester (A) and polyester (B) has a good handling property in drying. The shrinkable film for packaging of the present invention can be produced without any difficulty in drying and shows the ratio of shrinkage of 40 to 90% after 5-minute heat treatment at 100.degree. C.

Abstract: Disclosed herein is a thermal transfer (printing) material comprising a base material of a biaxially oriented polyethylene 2,6-naphthalate film of a Young's modulus in the longitudinal direction of not less than 600 kg/mm.sup.2 and a thermal transfer layer coated on the film.

Abstract: Disclosed herein is a thermal transfer (printing) film comprising:a base film,a stick-preventing layer provided on one side of said base film, said stick-preventing layer being provided at a rate of 0.01 to 1.9 g/m.sup.2 on one side of said base film, the center line average roughness of the surface of said stick-preventing layer being 0.03 to 0.15 .mu.m, the coefficient of parallel slipping of said stick preventive layer against glass surface being not more than 1.0, and the tensile strength of the film formed with said stick-preventing layer on one side thereof being not less than 8 kgf/mm.sup.2 when said film was elongated by 5% in the longitudinal direction, anda heat-melting ink layer provided on the other side of said base film.

Abstract: Disclosed herein is a polyethylene-2,6-naphthalate film suitable for magnetic recording tapes and, in particular, a polyethylene-2,6-naphthalate film suitable for a base film of high-density magnetic recording tapes, having a Young's modulus of not less than 800 kg/mm.sup.2 in the machine direction (the longitudinal direction) and of not less than 600 kg/mm.sup.2 in the transverse direction.

Abstract: Disclosed herein is a uniaxially high-oriented polyethylene naphthalate film for liquid crystal panel substrate which has an in-plane birefringence of more than 0.110 after the film is stretched and subjected to heatset treatment.

Abstract: Disclosed herein is a magnetic recording medium comprising a substrate polyester film having on both sides or one side thereof a coating layer comprising a polyurethane having anionic group or a mixture of a polyurethane having anionic group and a polyester having sulfonic group, and an electron radiation cured magnetic layer formed on said coating layer.

Abstract: Disclosed herein is a magnetic recording medium comprising a biaxially oriented polyester film having an extremely low surface roughness and containing fine particles and specific higher aliphatic carboxylic acids and/or derivatives thereof, and a magnetic layer formed on one side of the polyester film.The magnetic recording medium exhibits a stable travelling nature even when it is not provided with a back coat layer, and is usable as a high-quality and high-density magnetic recording medium.

Abstract: Disclosed herein is a process for producing a polyphenylene sulfide film, which comprises melt-molding polyphenylene sulfides in a sheet-like form from a die, casting the thus obtained sheet-like form onto a chilled drum on which an adhering liquid has been applied, while closely contacting the sheet-like form with the chilled drum surface by an electrostatic pinning method.

Abstract: There is disclosed a polyester film suitable for use in magnetic tapes having the characteristics represented by the following equations: ##EQU1## wherein N.sub.1 is the number of peaks of surface projections per millimeter;h is the average height in .mu.m of the surface projections;.theta. is the average steepness in degree of the surface projections;H.sup.2 is the mean square height in .mu.m.sup.2 of the surface projections; andn is the average refractive index.

Abstract: A uniaxially high-oriented polyethylene naphthalate film for polarizing plates which contains a dichroic dyestuff, having an in-plane birefringence or more than 0.110 after the film is stretched and subjected to heatset treatment.

Abstract: Disclosed herein is a biaxially oriented polyethylene naphthalate film having a center line average roughness [Ra(.mu.m)] and a film thickness [T(.mu.m)] which satisfy the following formula: ##EQU1## produced by the electrostatic cooling method from polymethylene naphthalate having a resistivity of 1.times.10.sup.7 to 5.times.10.sup.8 .OMEGA..cm as measured in the molten state.

Abstract: Disclosed herein is an electrical insulating material which comprises biaxially oriented polyethylene naphthalate film having a center line average roughness of 0.008 to 0.08 .mu.m as measured on the surface thereof and a resistivity of 5.times.10.sup.7 to 5.times.10.sup.10 .OMEGA..multidot.cm as measured in the molten state.