Toray Industries, Inc.

Seizo Aoki

Kenji Tsunashima

Takashi Mimura

Masaru Suzuki

Yukichi Deguchi

Toshiya Yoshii

Takashi Sumiya

Hirokazu Kurome

Itsuo Nagai

Kazuo Matsuura

Toshihiko Hiraoka

Seiya Sugiura

Hideyuki Yamauchi

Katsutoshi Miyakawa

Tetsuo Ikegami

Morishige Sonoda

Yukio Ota

Yasuji Nakahara

Tatsuya Ito

Polyester film for electrical insulation

A reflector used in a surface light source comprising a white polyester film in which fine voids are formed and whose apparent specific gravity is in the range of 0.5 to 1.2. The reflectance of the polyester film can be increased by the fine voids. When the reflector having a high reflectance is used in a surface light source having a side light system, a bright scope of, for example, a liquid crystal display easy to see can be obtained.

Polyester film reflector for a surface light source

A film suitable as a base of image transfer material for thermal recording or a heat-sensitive mimeograph stencil is disclosed. The laminated film of the present invention comprises a coating layer on at least one surface of a polyester film, which coating layer contains as a major component a wax-based composition and has protrusions with length/width ratios of not less than 3 at a density of not less than 20 protrusions/100 .mu.m.sup.2. The film of the present invention, when used as a base of an image transfer material for thermal recording or as a film for heat-sensitive mimeograph stencil, the running property is good, abrasion and staining of the head are very small, shedding of ink when the ink is applied does not occur, and the adhesion of the ink, clearness of printed characters, anti-sticking property, holing property and clearness of printing are excellent.

Laminated polyester film for heat-sensitive image transfer material

A polyester film, which is substantially non-oriented and whose main component is polyethylene terephthalate, is formed into a shape for example, a package, at a condition causing no yield point. The formation ability of the polyester film for forming is improved, and a formed body having a good uniformity in thickness can be obtained. Further, the range of the temperature condition causing no yield point can be enlarged by laminating a PET-system polyester, which originally tends to cause a yield point by itself, onto a polyester having no yield point. In such a laminated polyester film, the slipping property and releasing property from a mold of the film can be improved by specifying the ranges of the degree of crystallinity of each layer, the adhesive force at a high temperature of the film and the surface roughness of the film, and the shape of a formed body can be improved.

Process for forming a polyester film

This invention relates to a polyester film suited for use in optical recording medium. The polyester film of the present invention has a modulus of photoelasticity of not more than 0.9.times.10.sup.-3 mm.sup.2 /kgf, a maximum surface roughness Rt of not more than 100 nm and a mean interval Sm between adjacent surface projections of not less than 20 .mu.m, so that light scattering and interference are not caused, and optical strain is not generated even when a thermal stress or external force is exerted to the film. Thus, the polyester film of the present invention can be used as the supporting layer or cover layer of optical recording media such as optical cards, optical disks and optical recording tapes.

Polyester film having specific surface properties

Process for producing polyester film

Film for heat-sensitive mimeograph stencil

Growing community of inventors

Shiga, Japan

Seizo Aoki