| 摘要 |
PURPOSE:To get rid of occurrence of cracks on the side face of a molded item even if a high pressure is applied by coating the inner wall of a mold with a fluorinated resin when a molded item is prepd. by performing compression molding of a polyimide resin or a polyimide resin compd. consisting of a polyimide resin and a filler in a mold and thereafter calcining it. CONSTITUTION:As a polyimide resin, a compd. having mainly a polyimide structure of formula is used. Various fillers can be incorporated in the polyimide resin for providing moldability, dimensional stability, low water absorption properties, etc. As the type for molding, a polyimide resin powder is compressed in a mold wherein the inner wall is coated with a fluorinated resin to mold a compressed powder and then, it is calcined by heating. The pressure for molding the compressed powder is pref. 2,000-5,000kg/cm<2> and the calcining temp. is pref. 370-430 deg.C. The method for coating the inner wall of the mold with the fluororesin is not specifically restricted and e.g. a method wherein a commercially available 'Teflon' coating agent is applied by coating or by spraying can be used. |
