Ube Industries, Inc.

Kanzo Tabata

Hiroshi Inoue

Tadao Muramatsu

Yasuji Narahara

An aromatic polyimide film containing very fine particles of an inert inorganic material having an average particle diameter of 40 to 1,000 angstroms in an amount of 0.02 to 6.0 wt. %, wherein a surface of the film is provided with extremely small sized protrusions having a maximum height of 50 to 500 angstroms and an average diameter of 50 to 2,000 angstroms, the number of protrusions is in the range of 2.times.10.sup.5 to 1.times.10.sup.8 /mm.sup.2, and the number of protrusions having a diameter of not less than 1.5 times as much as the average diameter is not more than 5% of the total number of the protrusions. This polyimide film is suitably employable as a support of a magnetic recording medium.

Growing community of inventors

Hirakata, Japan

Kanzo Tabata