Nitto Electric Industrial Co., Ltd.

Keizo Mizobe

Yuzuru Noda

Masanori Imai

Koji Suzuki

Osamu Yoshikai

A polyimide molding powder and a process for producing the same are disclosed, said powder comprising an aggregate of polyimide particles, in which the whole or a large portion of said powder comprises polyimide particles composed of a particulate filler coated with a polyimide resin and/or polyimide particles composed of a fibrous filler coated with a polyimide resin, and said process comprising reacting an aromatic tetracarboxylic acid dianhydride and an aromatic diamino compound in an organic solvent to synthesize a polyimide precursor and imidating the polyimide precursor to precipitate polyimide particles, wherein a particulate filler and/or a fibrous filler dispersed in a prescribed amount of an organic solvent is or are added to the reaction system at any stage before the imidation of the polyimide precursor. The molding powder produces polyimide molded products free from brittleness and excellent in appearance, as well as various performance characteristics due to the improving effects of the filler.

Polyimide powder and process for producing the same

A polyimide powder which can provide a molding having excellent both strength and heat resistance by heat-press molding, and a method for producing such polyimide powder are disclosed. The polyimide powder comprises spherical polyimide particles having a particle size distribution of from 0.5 to 20 .mu.m and a mean particle diameter of from 1 to 15 .mu.m, and comprising a repeating unit represented by the formula ##STR1## wherein Ar represents an aromatic diamine residue.

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Osaka, Japan

Keizo Mizobe