Patent ID: 7303811
Filing Date: 2007-12-04
Classification: B29C,B29K,B29L,B32B,C08G,C08J,H01M,H05K,Y02E,Y10S,Y10T

Abstract:
1. A porous insulating film consisting essentially of a highly heat resistant polyimide resin film having a fine porous structure wherein: a) fine continuous channels reaching to both surfaces of the insulating film in a nonlinear fashion have a mean pore size of 0.01-0.2 μm in the center of the film and 0.4-0.9 μm at both surfaces of the film and a porosity of 15-80%; b) the polyimide resin film is prepared from a polyimide precursor solution and consists essentially of a polyimide obtained from the combination of at least one tetracarboxylic acid component and a diamine component; and c) the insulating film has and a heat shrinkage of not greater than about ±1% after being heat-treated at 105° C. for 8 hours, and does not contain a dense layer on either of the surfaces.