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:
May. 28, 1996
Filed:
Jan. 24, 1995
Masahiro Tsumura, Kamisu-machi, JP;
Masao Tashima, Kamisu-machi, JP;
Hiromi Miyasita, Kamisu-machi, JP;
Kashima Oil Co., Ltd., Tokyo, JP;
Abstract
A process for producing a highly reactive modified phenolic resin, comprising the steps of polycondensing a petroleum heavy oil or pitch, a formaldehyde polymer and a phenol in the presence of an acid catalyst to thereby prepare a modified phenolic resin; and reacting the resultant modified phenolic resin with a phenol in the presence of an acid catalyst but in the absence of a crosslinking agent such as a formaldehyde polymer to thereby lower the molecular weight of the modified phenolic resin. This highly reactive modified phenolic resin has a low number average molecular weight and a high phenol content, so that its resin melt viscosity is low and that it exhibits a markedly improved reactivity with an epoxy resin. Accordingly, the combination thereof with an epoxy resin provides a molding material suitable for producing a molding which is excellent in not only thermal resistance and moldability but also dimensional stability and other mechanical properties, especially a material for electrical or electronic part and a semiconductor sealer.