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:
Jul. 14, 1987
Filed:
Dec. 05, 1985
Masahiro Matsumura, Kadoma, JP;
Kenzi Ogasawara, Kadoma, JP;
Atsuhiro Nakamoto, Kadoma, JP;
Yoshihisa Sugawa, Kadoma, JP;
Matsushita Electric Works, Ltd., Osaka, JP;
Abstract
Superior polyimide prepolymers particularly suitable for fabrication of multi-layer printed boards are produced by reacting unsaturated bisimides with diamines to consist essentially of 41-55% of unreacted reactants, 39-54% of components having a molecular weight of between 400 and 15,000, and 3.0-6.8% of components having a molecular weight of more than 15,000. The resulting prepolymers enable the preparation of their solution having enough working life for successfully impregnating a given substrate therewith in the preparation of prepregs. The prepregs, prepared from the above prepolymers in such a way as to contain within the resin content thereof 29-35% of unreacted reactants, 51-65% of the components having a molecular weight of between 400 and 15,000, and 5-14% of the components having a molecular weight of more than 15,000, allow the fabrication of laminate products with remarkable dimension stability under a low molding pressure to eliminate the presence of voids in the products, in addition to that the prepregs ensure a high bond strength as well as elongated working life which is responsible for prevention of a blister in the finished laminate and for easy control of the laminate forming process.