US Patent 7186456 Easily slidable polyimide film and substrate employing it

An easily slidable polyimide film having a polyimide surface layer comprising a polyimide which is thermoplastic and has a glass transition temperature of 190–450° C., wherein there are dispersed in the polyimide of the polyimide surface layer, in a proportion of approximately 0.5–10 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 0.3–0.8 μm and a maximum size of no greater than 2 μm, in at least about 1 μm of the polyimide surface layer.