Diafoil Hoechst Company, Limited

Diafoil Company, Ltd.

Masashi Inagaki

Shigeo Utsumi

Kazuo Endo

Chikakazu Kawaguchi

Yuko Watanuki

Takashi Harada

Narihiro Masuda

Toshifumi Takisawa

Yoshio Meguro

Masahiko Fujimoto

Nobuyasu Shudo

Seiji Sakamoto

Tomoyuki Kotani

Naohiro Takeda

Shin-ichi Kinoshita

Yoshihiko Ito

Yuzo Otani

Kichinojo Tomitaka

Nariaki Okajima

Kenji Kato

Shigeyuki Watanabe

Kazuyuki Akatsu

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.

Biaxially oriented polyester film for magnetic recording medium

Disclosed herein is a polyethylene naphthalate multilayered film for a high density magnetic recording medium comprising:

Polyethylene naphthalate multilayered film for high density magnetic

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.

Base film of digital compact cassette tape

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.

Laminated polyester film for magnetic tape having specific surface

A multilayered polyester film for high-density magnetic discs, comprising a layer of polyester (A) and a layer of polyester (B) having a thickness of not more than 3 .mu.m, being laminated on at least one side of the layer of polyester (A) and having specific surface characteristics.

Polyester multilayered film for high-density magnetic disc

Disclosed herein is a magnetic recording medium comprising a polyester film layer, a coating type magnetic layer provided on one side of said polyester film layer, and a back-coat layer provided on the other side of said polyester film layer.

Magnetic recording medium comprising a polyester film substrate, a

Disclosed herein is a polyester film containing specific fine spherical silica particles. The film of the present invention is especially suitable as a base film for a magnetic recording medium or dielectric for a capacitor. The films of the present invention have the markedly improved properties such as surface properties, electromagnetic properties, electrical properties, etc. due to the excellent dispersibility of the particles in the film.

Polyester films, magnetic recording media and film capacitors produced

Disclosed herein is a polyester film containing specific fine spherical silica particles. The film of the present invention is especially suitable as a base film for a magnetic recording medium or dielectric for a capacitor. The films of the present invention have the markedly improved properties such as surface properties, electromagnetic properties, electrical properties, etc. due to the excellent dispersibliity of the particles in the film.

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Machida, Japan

Masashi Inagaki