Gunze Limited

Tsuneo Miyamoto

Takashi Kuraoka

Junya Kanetake

Naoki Nishiura

Nobuaki Kobayashi

Tsutomu Yoshida

Tetsuo Sadamitsu

The present invention provides an electrically-semiconductive poly(amic acid) liquid composition and a use thereof. An electrically-semiconductive poly(amic acid) (polyimide precursor) liquid composition whose electrical semiconductivity is applied by comprising an electrically-conductive carbon black. Change in an electrical resistivity of the liquid composition after being stored for 180 days at a temperature of 23&deg; C. and in an atmosphere of a RH of 65% is 7% or less based on the electrical resistivity immediately after the preparation of the liquid composition. The electrically-semiconductive poly(amic acid) liquid composition is obtainable by mixing 5-40 parts by weight of a poly(amic acid), 95-60 parts by weight of an organic polar solvent and 10-40% by weight based on the poly(amic acid) of an electrically-conductive carbon black having a volatile content of 5-20%, a specific surface area of 100-300 m,/g and a pH of 2-4. The electrically-semiconductive poly(amic acid) liquid composition is used for molding an electrically-semiconductive seamless tubular polyimide film, for example, which is usable as an intermediate belt member for fixation and transfer of toner in a copying machine.

Electrically-semiconductive poly(amic acid) liquid compositions and their use

A seamless tubular composite film wherein a seamless tubular film comprising fluororesin with a film thickness of 5-20 &mgr;m stretched 2-10% in circumferential direction is fitted on the outside of a seamless tubular film comprising a thermosetting polyimide resin, or the precursor polyamic acid and heated at 200-400&deg; C. for anchorage. In addition, in order to give thermal conductivity and antistatic properties leading to inhibition reduction of heating time and inhibition of adhesion of dirt, boron nitride and compatible thermal conductive agents may be dispersed in the polyimide resin, and carbon black and like electric conductive agent may be dispersed in fluororesin. The film is useful as toner fusing member, such as in electrophotographic copying machines and in laser printing.

Seamless tubular composite film and method for producing the same

The present invention relates to a heat-conductive polyimide film comprising a heat-conductive powder dispersed therein with a concentration gradient. The film can be produced, for example, by centrifugal casting. The film can be used as an excellent component or member in those fields in which heat conductivity is required in addition to mechanical characteristics, heat resistance and chemical resistance. For example, it is used as a thermal fixation member in a laser printer.

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Moriyama, Japan

Tsuneo Miyamoto