Abstract: A polyimide film having sufficiently excellent characteristics such as a sufficiently high elastic modulus, a low water absorption, a small coefficient of moisture-absorption expansion, a small coefficient of linear expansion and a high dimensional stability; and various electric/electronic equipment bases with the use of the polyimide film. A polyimide film having a tensile elastic modulus of 700 kg/mm2 or less and a coefficient of moisture-absorption expansion of 20 ppm or less and containing a specific repeating unit as an essential repeating unit is synthesized. Then various electric/electronic equipment bases such as a laminate for flexible print connection boards are produced by using the polyimide film.

Abstract: The object of the present invention is to provide a polyimide film, a flexible printed wiring board consisting thereof, and a polyimide molding, wherein various metal compounds are added to improve their properties and to provide them with noble properties.

Abstract: A fluoro-carbon resinous laminate has a crack-resistant surface on a fluoro-carbon resinous layer thereof produced by coating a single surface or both surfaces of a plastic film with a single layer of a fluoro-carbon resinous dispersion, and a method of producing the laminate. To produce the fluoro-carbon resinous laminate, which is a minimum of 10 .mu.m in thickness, a single surface or both surfaces of a plastic film are coating with a single layer of concentration-adjusted fluoro-carbon resinous dispersion and then dried, followed by curing the resinous dispersion in a thermal treating furnace with heated atmospheric air or by adding organic solvent to the resinous dispersion, the enabling production of a fluoro-carbon resinous laminate having a surface appearance in which cracks cannot visually be identified.

Abstract: A method of molding an aromatic polyimide resin, comprising compression molding an aromatic polyimide resin composition powder comprising an aromatic polyimide resin and a fluorine resin added thereto, and then sintering the compression molded product in a mixed gas atmosphere of oxygen and inert gas, having the oxygen concentration of 0.1 to 10% at 360.degree. to 480.degree. C., or sintering the compression molded product in an inert gas atmosphere and then heat treating the same in a mixed gas atmosphere of oxygen and inert gas at 360.degree. to 480.degree. C. This method can solve the problems on color shade and strength due to sintering in the case of molding an aromatic polyimide resin having a fluorine resin added thereto, and can provide a polyimide molding having excellent quality.

Abstract: The present invention provides a copolyimide characterized in that the copolyimide contains units represented by formulas (I) and (II) ##STR1## (wherein R.sub.0 represents an aromatic tetracarboxylic residue). The polyimide has excellent thermal dimensional stability, and can be fabricated by using conventional inexpensive materials.

Abstract: Disclosed is a film of polyimide having repeating units of formula (1) and a birefringence (.DELTA.n) of at least 0.13: ##STR1## wherein R.sup.1 is an aromatic group having a valency of 4, at carbon atoms constituting the aromatic ring, and R.sup.2 is an aromatic group having a valency of 2, at carbon atoms constituting the aromatic ring. This polyimide film exhibits good thermal dimensional stability.

Abstract: A polyimide copolymer having a repeating unit of formula (I): ##STR1## wherein each of R.sub.1 and R.sub.2 is independently ##STR2## and R.sub.1 and R.sub.2 are different from each other, R.sub.0 is an aromatic group having a valency of 4, and m is a positive integer. The polyimide copolymer is excellent in heat resistance, mechanical properties (e.g., tensile elongation) and thermal dimensional stability.