Ube Industries, Inc.

Katsumi Kato

Tomohiko Yamamoto

Toshinori Hosoma

Shuichi Hashiguchi

Kazuhiko Yoshioka

A polyimide film favorably employable in a method of producing a through-hole in an aromatic-polyimide film having on its surface a laminated or deposited metal film by applying laser beam onto the polyimide film, preferably is composed of a high Tg aromatic polyimide layer which has a Tg of 300&deg; C. or higher or has no noticeable Tg and is produced from a biphenyltetracarboxylic acid compound and an aromatic diamine compound and a low Tg aromatic polyimide layer which has a Tg of lower than 375&deg; C. but higher than 200&deg; C., provided that the Tg of the low Tg polyimide layer is lower than the Tg of the high Tg polyimide layer and the metal film is laminated or deposited on the surface of the low Tg polyimide layer on the side not facing the high Tg polyimide layer.

Method of producing through-hole in aromatic polyimide film

A roll of a web composed of an aromatic polyimide composite film and a metal film in which the polyimide composite film is composed of a non-thermoplastic aromatic polyimide base film and a thermoplastic aromatic polyimide cover film, the polyimide composite film showing a heat shrinkage ratio of less than 0.1% at 300&deg; C., can be produced by heating a corresponding roll of web composed of a metal film and an aromatic polyimide composite film having a heat shrinkage ratio of more than 0.1% at 300&deg; C., at a temperature between 150&deg; C. and a glass transition temperature of the thermoplastic aromatic polyimide cover film, for a period of at least one minute.

Roll of metal film/aromatic polyimide film composite web

An aromatic polyimide laminate composed of an aromatic polyimide composite film, a metal film, and a release film is disclosed. The aromatic polyimide composite film is composed of an aromatic polyimide substrate film and two thermoplastic aromatic polyimide layers. Each thermoplastic layer is fixed to each surface of the substrate film. The substrate film has no glass transition temperature of lower than 350&deg; C., and the thermoplastic aromatic polyimide layer has a glass transition temperature of 190-280&deg; C. The metal film is fixed, with no intervening adhesive layer, to one thermoplastic aromatic polyimide layer at a 90&deg; peel strength of 0.8 kg/cm or more and the release film is fixed, with no intervening adhesive layer, to another thermoplastic aromatic polyimide layer at a 90&deg; peel strength of 0.001-0.5 kg/cm, under such condition that the latter peel strength is one half or less of the former peel strength.

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Yamaguchi, Japan

Katsumi Kato