Abstract: A method of manufacturing a divided laminated iron core, wherein the iron core laminae includes first iron core laminae and second iron core laminae, includes: a first connecting-portion punching step of punching each of connecting portions between divided iron core pieces constituting each first iron core lamina in a sheet steel strip; a second connecting-portion punching step of punching each of connecting portions between divided iron core pieces constituting each second iron core lamina; and a stacking step of stacking at least one of the first iron core laminae and at least one of the second iron core laminae and joining together the stacked iron core laminae, wherein the connecting portions between the divided iron core pieces of each first iron core lamina are configured to be separated more easily than the connecting portions between the divided iron core pieces of each second iron core lamina.

Abstract: A method of manufacturing a divided laminated iron core, wherein the iron core laminae includes first iron core laminae and second iron core laminae, includes: a first connecting-portion punching step of punching each of connecting portions between divided iron core pieces constituting each first iron core lamina in a sheet steel strip; a second connecting-portion punching step of punching each of connecting portions between divided iron core pieces constituting each second iron core lamina; and a stacking step of stacking at least one of the first iron core laminae and at least one of the second iron core laminae and joining together the stacked iron core laminae, wherein the connecting portions between the divided iron core pieces of each first iron core lamina are configured to be separated more easily than the connecting portions between the divided iron core pieces of each second iron core lamina.

Abstract: A precursor of a polybenzoxazole resin which comprises a crosslinking group in a molecule and has a specific structure, a polybenzoxazole resin obtained from the precursor by the condensation reaction and the crosslinking reaction, an insulating film comprising the polybenzoxazole resin and a semiconductor device comprising an insulating interlayer film in multi-layer wiring or a film for protecting surfaces which comprises the above insulating film. The precursor exhibits excellent processability due to excellent solubility in solvents and, after the ring closure, excellent heat stability in applications. The resin exhibits excellent electric, physical and mechanical properties and is advantageously used for insulating interlayer films of semiconductor devices and the like applications.

Abstract: A precursor of a polybenzoxazole resin which comprises a crosslinking group in a molecule and has a specific structure, a polybenzoxazole resin obtained from the precursor by the condensation reaction and the crosslinking reaction, an insulating film comprising the polybenzoxazole resin and a semiconductor device comprising an insulating interlayer film in multi-layer wiring or a film for protecting surfaces which comprises the above insulating film.

Abstract: A heat resistant resin composition comprising, as the main components,(A) 100 parts by weight of an organic solvent-soluble polyimide resin having a glass transition temperature of 350.degree. C. or less,(B) 5 to 100 parts by weight of an epoxy compound having at least two epoxy groups in one molecule, and(C) 0.1 to 20 parts by weight of a compound having an active hydrogen group which can react with the epoxy compound (B),a heat resistant film adhesive comprising, as the main components, the above components (A), (B) and (C), and a process for producing a heat resistant film adhesive by casting a solution of the above heat resistant resin composition on one side or both sides of a support.

Abstract: The present invention provides a film adhesive comprising, as the main constituent, a polyimide resin having a glass transition temperature of 350.degree. C. or lower and soluble in organic solvents, which polyimide resin is obtained by reacting at least one of the following acid components (A) and (B)(A) 4,4'-oxydiphthalic acid dianhydride(B) 3,3',4,4'-biphenyltetracarboxylic acid dianhydride and/or 3,3',4,4'-benzophenonetetracarboxylic acid dianhydridewith at least one of the following amine components (C) and (D)(C) a siloxane compound represented by the following general formula (1) and/or 2,2-bis(4-(4-amino-phenoxy)phenyl)propane ##STR1## wherein R.sub.1 and R.sub.2 are each a bivalent aliphatic (C.sub.1-4) or aromatic group; R.sub.3, R.sub.4, R.sub.5 and R.sub.6 are each a mono-valent aliphatic or aromatic group; and k is an integer of 1-20,(D) bis(aminophenoxy)benzene and/or dimethylphenylene-diamineto give rise to ring closure of imide, as well as a process for producing said film adhesive.