Abstract: The present invention relates to a process for producing a polyester sheet comprising melt-extruding a polyester resin by using a vent-type twin-screw extruder in sheet-wise onto the surface of a rotating chilling drum under the condition satisfying the following formula (1):5.2.times.10.sup.-6 .times.D.sup.2.8 .ltoreq.Q/N.ltoreq.15.8.times.10.sup.-6 .times.D.sup.2.8 (1)wherein D mm represents the inner diameter of the extruder cylinder, Q kg/hr represents the extrusion rate per unit time and N rpm represents the screw number of revolution.

Abstract: A biaxially oriented laminated polyester film, comprises a layer A having a thickness of 0.5 .mu.m, composed of a polyester having no crystalline melt peak at not less than 230.degree. C. in the differential thermal analysis and laminated on at least one surface of another polyester layer, with a coating layer containing not less than 50 wt % of an acrylic resin or urethane resin as a coating component being formed on the surface of said layer A.

Abstract: A metallized polyester film capacitor is composed of a metallized polyester film comprising: a polyester film; a coating layer composed of a water-soluble or a water-dispersible polyester resin or polyurethane resin wherein the coating layer is formed on at least one side of the polyester film and wherein the alkali metal content of said coating layer is no more than 126.5 ppm; and a vapor-deposited metal on the coating layer.

Abstract: A metal-deposited polyester film capacitor made of a laminated or wound metal-deposited polyester film which has, on at least one of its surface, a coating layer containing an aromatic polyurethane and a deposited metal layer on the coating layer, which is excellent in moist-heat resistance and has good long-term reliability.

Abstract: The disclosure describes a polyester film for sublimation-type thermosensitive transfer, comprising a polyester film having the degree of planar orientation of 0.145 to 0.169, and a coating layer formed by applying a water solution or a water dispersion composed of at least one water-soluble or water-dispersible resin selected from the group consisting of urethane-based resins, polyester-based resins and acrylic-based resins, on at least one side of the film before oriented crystallization of said film is completed, and subjecting the coated polyester film to drying treatment, stretching treatment and heat-setting treatment.

Abstract: Disclosed herein is a metallized polyester film capacitor comprising:a polyester film;a coating layer formed on at least one side of said polyester film, said coating layer having a thickness (t) of 0.01 to 2 .mu.m and containing 0.1 to 20 wt % of the particles having an average diameter (D) that satisfies the following formula (I); anda metal layer deposited on at least one side of the polyester film having said coating layer.0.5.ltoreq.D/t.ltoreq.

Abstract: The disclosure describes a high-density magnetic recording medium comprising a biaxially oriented, laminated polyester film which is coextruded, so that a polyester A layer subject to plastic deformation by calendering treatment forms one of the surfaces of a base film, anda magnetic layer formed on the surface of the polyester A layer and composed of a magnetic substance dispersed in a resin binder,the thickness (t.sub.A) of the polyester A layer and the thickness (t.sub.M) of the magnetic layer satisfying the following formulae at the same time.0.01 .mu.m.ltoreq.t.sub.M .ltoreq.2.0 .mu.m (1)0.05 .mu.m.ltoreq.t.sub.A (2)t.sub.A +t.sub.M .ltoreq.5 .mu.m (3).

Abstract: An optical tape comprising a substrate having a center line average roughness (Ra.sup.A) on one side of 0.005 to 0.5 .mu.m and a tensile strength (F.sub.5) in the longitudinal direction of not less than 8 kg/mm.sup.2, and an optical recording layer formed on the other side of said substrate.

Abstract: A heat sensitive original sheet for stencil printing made of a laminate of a paper sheet and a biaxially oriented polyester film having a melting point of 150.degree. to 240.degree., a thickness of 0.2 to 3 .mu.m, an average refractive index of 1.570 to 1.578, a thermal shrinkage stress of 100 to 800 g/mm.sup.2 after being treated at 80.degree. C. for 10 seconds, a thermal shrinkage factor of 5 to 50% after being treated at 80.degree. C. for 10 minutes, a shrinkage factor of 15% or less after being treated in toluene at 25.degree. C. for 10 minutes, and a center line average surface roughness of 0.02 to 0.3 .mu.m, which original sheet is excellent in a perforation sensitivity, resistance to curling, and resolution and image density of a printed image.

Abstract: Disclosed herein is a polyethylene naphthalate multilayered film for a high density magnetic recording medium comprising:a polyethylene naphthalate layer (A), anda polyethylene naphthalate layer (B) laminated on at least one surface of said polyethylene naphthalate layer (A) and having a thickness of not more than 2 .mu.m and specific surface characteristics,the multilayered film having Young's modulus of not less than 700 kg/mm.sup.2 in machine and transverse directions.

Abstract: A laminated polyester film comprising a polyester film and a layer comprising an antistatic agent and formed on at least one side of the polyester film, the antistatic agent being a high-molecular-weight antistatic agent having a nitrogen atom-containing group and a sulfonic acid or sulfonate group.

Abstract: A polyester film for an image-forming transfer material, wherein a difference .DELTA..alpha..sub.t between the maximum coefficient of thermal expansion and the minimum coefficient of thermal expansion in the film plane is not larger than 1.0.times.10.sup.-5 /.degree.C., and the maximum coefficient of thermal expansion .alpha..sub.tmax is not larger than 2.5.times.10.sup.-5 /.degree.C., which can form a high quality color image having less deviation and a high image density.

Abstract: A film for heat-sensitive stencil paper comprising a biaxially oriented film having a thickness of 0.5 to 6.0 .mu.m and formed from a polyester composition comprising polybutylene terephthalate and at least one other polyester, the content of the polybutylene terephthalate in the polyester composition being 20 to 80 wt %, the polyester composition has one melting point or a plurality of melting points with a difference of less than 10.degree. C. between the highest melting point and the lowest melting point.

Abstract: Disclosed herein is an optical tape comprising: a substrate whose a center-line average roughness (Ra.sup.B) on the surface of one side is not more than 0.005 .mu.m and the number of coarse protuberances having a height of not less than 0.10 .mu.m in the surface of that side is not more than 10 protuberances/cm.sup.2, and an optical recording layer formed on the surface whose the Ra.sup.B is not more than 0.005 .mu.m.

Abstract: A base film of a digital compact cassette tape comprising at least two layers consisting of laminated biaxially oriented polyester films, one surface of which has center line average roughness of 5 to 20 nm, and the other surface of which has center line average roughness of 15 to 45 nm, and which has a Young's modulus in a machine direction of at least 600 kg/mm.sup.2, which base film is excellent in running stability and electromagnetic conversion characteristics.

Abstract: A polyester resin film which is biaxially oriented and again oriented in a machine direction and a coating layer formed on at least one surface of the film, in which the coating layer contains at least 50% by weight of a water-soluble or water-dispersible polyester resin having a glass transition temperature of at least 20.degree. C., which film has a good adhesion property.

Abstract: A capacitor comprising a polyethylene 2,6-naphthalate film as a base film, a coating layer, formed on at least one surface of said base film, which coating layer comprises a water-soluble or water-dispersible resin and has a center line average surface roughness (Ra) of 0.005 to 0.5 .mu.m, and a metal layer deposited on said coated polyethylene 2,6-naphthalate film, wherein said coated polyethylene 2,6-naphthalate film has an F5 value in a machine direction of at least 1.5.times.10.sup.8 Pa, a Young's modulus in a machine direction of at least 5.9.times.10.sup.9 Pa, and a Young's modulus in a transverse direction of at least 5.9.times.10.sup.9 Pa, which capacitor has good moist-heat resistance and long-term stability.

Abstract: A poly(ethylene 2,6-naphthalate) film obtained by stretching a poly(ethylene 2,6-naphthalate) sheet containing cross-linked polymer particles which have at least one ethylene glycol unit and have an average particle size of from 0.05 to 3 .mu.m and a spherical ratio of from 1.0 to 1.1, wherein a deformation ratio of the cross-linked polymer particles in the stretching is from 1.2 to 3.0, has excellent runnability, abrasive resistance and strength.

Abstract: A laminated polyester film having a first polyester layer B and a second polyester layer A which is laminated on at least one surface of the polyester layer B and contains 0.05 to 10% by weight of particles having an average particle size of 0.005 to 1.0 .mu.m based on the weight of the polyester layer A, in which a ratio of a thickness of the polyester layer A to a particle size of particles contained in the polyester layer B is from 0.5 to 10, the numbers of protrusions on a surface of the polyester layer A which give second order interference fringes, third order interference fringes and fourth or higher order interference fringes in a multiple beam interference method using light having a wavelength of 540 nm are from 5 to 60/mm.sup.2 , not larger than 20/mm.sup.2 and not larger than 3/mm.sup.2, respectively, which film has good runnability and abrasion resistance and provides a magnetic recording medium with good electromagnetic conversion characteristics.

Abstract: A polyester film prepared through a lamination of at least two layers by coextrusion, wherein one of exposed surfaces (surface A) has a center line average roughness of from 0.002 to 0.015 .mu.m, a polyester layer forming the other of the exposed surfaces (surface B) has a lower melting point than a polyester forming the surface A, and the surface B has a degree of planar orientation of not larger than 0.100, which can be used as a base film for magnetic recording tape having no back coating.