The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Dec. 08, 1981
Filed:
Dec. 14, 1979
Hideyo Hirata, Ibaraki, JP;
Takeshi Hakamada, Hitachi, JP;
Misao Souma, Hitachi, JP;
Masao Matsui, Hitachi, JP;
Yoshiyuki Suda, Hitachi, JP;
Yoshiharu Karasawa, Hitachi, JP;
Toshikazu Narahara, Hitachi, JP;
Hitachi, Ltd., Tokyo, JP;
Abstract
An insulation system for winding of electric rotating machines having thermal resistance of class H or more and excellent adhesiveness between a conductor and an insulating layer and resistance to thermal stress can be produced by wrapping a plurality of layers of an insulating tape or sheet having thermal resistance of class H or more around a winding conductor, impregnating the thus treated winding conductor with a solventless varnish consisting essentially of 1 equivalent of an epoxy compound containing at least two vicinal epoxy groups, more than one equivalent of an organic polyisocyanate, and then heating the inpregnated winding conductor at a temperature above 60.degree. C. for a time sufficient to form and cure a resin containing as recurring units at least two isocyanurate rings directly bonded to one another through the residue of the polyisocyanate and two oxazolidone rings directly bonded to each other through the residue of the polyepoxide in the presence of 0.01-10% by weight of a catalyst which forms the isocyanurate rings and oxazolidone rings based on the total amount of the polyepoxide and polyisocyanate.