Ube Industries, Inc.

Toshiyuki Nishino

Toshihiko Anno

Tomohiko Yamamoto

Takeshi Uekido

Masafumi Hashimoto

Kenji Kuniyasu

Hiroshi Inoue

Hiroaki Yamaguchi

Takuji Takahashi

Yuji Matsui

Kenji Matsubara

Kazuhiko Yoshioka

Kazuhiko Mitsui

Kiyoshi Kumagawa

Takashi Amane

Akinori Ohtani

An adhesion-enhanced polyimide film which includes a core layer composed of a polyimide (a) having high rigidity and a low linear expansion coefficient, at least one side of which has a thin-layer formed by heating a coated layer including a heat-resistant surface treatment agent and a polyimide precursor which yields a highly heat-resistant amorphous polyimide (B).

Adhesion-enhanced polyimide film, process for its production, and laminated body

An easily slidable polyimide film having a polyimide surface layer comprising a polyimide which is thermoplastic and has a glass transition temperature of 190&#x2013;450&#xb0; C., wherein there are dispersed in the polyimide of the polyimide surface layer, in a proportion of approximately 0.5&#x2013;10 mass % based on the polyimide of the polyimide surface layer, wholly aromatic polyimide particles made of a polyimide comprising at least 80 mass % of a pyromellitic acid component and a p-phenylenediamine component, and having a median size of 0.3&#x2013;0.8 &#x3bc;m and a maximum size of no greater than 2 &#x3bc;m, in at least about 1 &#x3bc;m of the polyimide surface layer.

Easily slidable polyimide film and substrate employing it

A metal film/aromatic polyimide film laminate is composed of a composite aromatic polyimide film and a metal film, in which the composite aromatic polyimide film is composed of an aromatic polyimide substrate film having a linear expansion coefficient of 5&times;10 to 30&times;10 cm/cm/&deg; C. in the temperature range of 50-200&deg; C. (measured in machine direction), and a thin aromatic polyimide layer of polyimide prepared from a carboxylic acid component comprising a mixture of 3,3&prime;,4,4&prime;-biphenyltetracarboxylic dianhydride and 2,3,3&prime;,4&prime;-biphenyltetracarboxylic dianhydride in a molar ratio of 50:50 to 90:10 and an aromatic diamine component composed of 1,3-bis(4-aminophenoxy)benzene or a mixture of 1,3-bis(4-aminophenoxy)benzene and p-phenylenediamine and/or diaminodiphenyl ether in a molar ratio of 10/90 or more. Tg of the thin polyimide layer is 210-310&deg; C. The metal film is fixed to the thin polyimide layer at a 90&deg; peel resistance of 0.5 kg/cm or higher, while the thin polyimide layer is bonded to the substrate film at a 90&deg; peel resistance higher than that between the metal film and the thin layer.

Metal film/aromatic polyimide film laminate

Aromatic polyimide film and its composite sheet

An aromatic polyimide film useful as a face for a magnetic recording material having a back face-side half stratum thereof containing principal filler fine particles which provide a low friction back face-side surface having a centerline average surface roughness of 2 to 10 m .mu.m, and a front face-side half stratum thereof free from the principal filler particles and optionally containing additional filler fine particles having a size of 0.05 to 0.7 time that of the principal filler particles in a concentration of 0.1 to 0.8 time that of the principal filler particles, which additional filler particles provide a high smoothness front face-side surface having a centerline average surface roughness (Ra) of 0.1 to 0.8 time that of the back face-side surface, is produced from a first aromatic polyamic acid solution containing the principal filler particles and a second aromatic polyamic acid solution free from the principal filler particles and optionally containing the additional filler particles, by forming a film-shaped composite solution stream consisting of a first film-shaped solution stream united with a second film shaped solution stream, solidifying the film-shaped composite solution stream, and heat treating the solidified film to convert the polyamic acid to a corresponding polyimide.

Magnetic recording medium substrate comprising an aromatic imide polymer

Disclosed is an aromatic polyimide film which is well resistant to sagging and dimensional change in the heat treatment. The aromatic polyimide film is formed from a polymer solution which is produced by a polymerization reaction of a biphenyltetracarboxylic acid component and a phenylenediamine component, and characterized in that any rectangle optionally supposed within the film has a ratio between a length of any side and a length of the central portion between the side and a side opposite thereto is in the range of 100:100 to 100:100.15, and a heat shrinkage ratio of the film is not more than 0.3% (0.003) in any direction after the film is heated at 300.degree. C. for 2 hours. A process for the preparation of the above aromatic polyimide film is also disclosed.

Aromatic polyimide film and process for the preparation of the same

A dimensionally stable polyimide film and processes for the preparation thereof. The polyimide film is composed of an aromatic polyimide obtained from a solution of a polymer formed by polymerization of a biphenyl-tetracarboxylic acid and a phenylene diamine, wherein the average linear expansion coefficient of the polyimide film in the temperature range of from 50.degree. C. to 300.degree. C. is 0.1.times.10.sup.-5 to 2.5.times.10.sup.-5 cm/cm..degree.C., the ratio of the linear expansion coefficient in the machine direction of the film to the linear expansion coefficient in the transverse direction of the film is in the range of from 1/5 to 4, and the thermal dimension stability expressed by the ratio of the change of the size of the film at normal temperature after the heat treatment where the temperature is elevated to 400.degree. C. from normal temperature and the film is maintained at 400.degree. C. for 2 hours is less than 0.3%.

Dimensionally stable polyimide film and process for preparation thereof

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Ube, Japan

Toshiyuki Nishino