Abstract: Composite fibrous products such as composite cloth, composite strings, composite knitted goods, etc., produced by using combination yarns obtained by twisting one or more aromatic polyamide continuous filament yarns and one or more continuous glass yarns have high rigidity and excellent reinforcing effects.

Abstract: A curable polyamino-bis-imide resin, obtained by the thermal reaction of:(A) a bis-imide represented by the general formula I: ##STR1## wherein R.sub.1 stands for a divalent organic group having a carbon-carbon double bond and R.sub.2 for a divalent aromatic organic group having 1 to 3 benzene rings, with(B) a diamine represented by the general formula II: ##STR2## wherein X stands for one member selected from the group consisting of O, S, SO.sub.2, CH.sub.2, CO, COO, C(CH.sub.3).sub.2, CF.sub.2 and C(CF.sub.3).sub.2, providing that the three X's may be identical or not identical to one another and the hydrogen atoms attached to the benzene rings may be substituted by an inactive alkyl group, perfluoroalkyl group or halogen atom, a solution thereof, cross-linked resins therefrom and laminated boards therefrom.

Abstract: A transparent and homogeneous polyimide resin solution produced by a process in which a tetracarboxylic acid component and an aromatic diamine component are subjected to polymerization and imidization by one step at 100.degree. to 200.degree. C. by use of a halogenated phenolic compound as a solvent, permits the formation of a polyimide film excellent in mechanical properties.

Abstract: Copper-clad laminates for printed wiring boards with almost no warpage can be produced continuously without using a solvent by continuously running a continuous, fibrous substrate, supplying partially and intermittently a solventless thermosetting resin mixture to the running substrate, laminating a copper foil at least one surface of the running substrate, pressure molding with heating the copper foil laminated substrate in a mold comprising a pair of flat plates at least one of which has projecting portions tapered to the center of the flat plate at the periphery thereof, taking off and cutting the molded laminate.

Abstract: An improved method of preparing polyamide acid for processing of semiconductors from a diamine and a tetracarboxylic acid dianhydride with a diaminocarbonamide, is provided (1) by reacting the components at below 40.degree. C. until the reduced viscosity reaches above 0.5 dl/g. at 30.degree. C., and then, (2) by adjusting the reduced viscosity to more than 0.3 dl/g, at 30.degree.0 C. and the solution viscosity to 500-3,000 cps at 25.degree. C. by heating at 50.degree.-100.degree. C. By applying the polyamide acid obtained by the method to semiconductor apparatus, they get sufficient heat-resistance without pin holes, and their reliability may be greatly improved.

Abstract: An improved method of preparing polyamide acid for processing of semiconductors from a diamine and a tetracarboxylic acid dianhydride optionally with a diaminocarbonamide, is provided (1) by reacting the components at below 40.degree. C. until the reduced viscosity reaches above 0.5 dl/g. at 30.degree. C. and then, (2) by adjusting the reduced viscosity to more than 0.3 dl/g, at 30.degree. C. and the solution viscosity to 500-3,000 cps at 25.degree. C. by heating at 50-100.degree. C. By applying the polyamide acid obtained by the method to semiconductor apparatus, they get sufficient heat-resistance without pin holes, and their reliability may be greatly improved.

Abstract: A laminate produced by molding under heat and pressure a plurality of prepregs obtained by impregnating a resin into a composite fabric, either woven or nonwoven, comprising aromatic polyamide fibers and glass fibers has a low linear expansion coefficient and excellent interlaminar strength.

Abstract: A method of preparing a polyamide acid type intermediate is provided, by using a purified inert solvent and monomer compounds, or diamine and/or diaminoamide compounds and a tetracarboxylic acid dianhydride, whose ionic impurities and free acid contents were reduced by recrystallization purification. The polyamide acid type intermediate may improve electrical properties and heat resistance of semiconductors when it is applied to, for instance, a surface-protecting film of semiconductors or an interlayer-insulating film of semiconductors having a multiple layer wiring structure.

Abstract: Method of making a semiconductor device which includes applying a solution of a heterocyclic ring-containing polymer in an organic solvent to a desired surface of a semiconductor body and removing the organic solvent from the solution by heat thereby to form a coating of a polymer on the surface, wherein the polymer is a reaction product of a diamine represented by the formula: ##STR1## with a tetracarboxylic acid or anhydride of it. Since the coating exhibits good thermal stability and good electrical properties when applied to the surface of the semiconductor, it is useful as a passivating film.

Abstract: An epoxy resin composition having a remarkably improved storage stability and an excellent hardening characteristic when heated, which comprises an epoxy resin and an aromatic amino carboxylic acid or a derivative thereof as a hardener for the epoxy resin. This composition can be molded by injection molding, heretofore being deemed inapplicable to epoxy resin compositions, whereby the molded articled of epoxy resin can be produced with a high molding efficiency.