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:
Jan. 12, 1999
Filed:
Feb. 21, 1996
Applicant:
Inventors:
Assignee:
Mitsubishi Denki Kabushiki Kaisha, Tokyo, JP;
Primary Examiner:
Int. Cl.
CPC ...
C08G / ;
U.S. Cl.
CPC ...
528 31 ; 528 10 ;
Abstract
A high-purity silicone ladder polymer of high molecular weight which contains 1 ppm or less of sodium, potassium, iron, copper, lead, magnesium, manganese and chlorine, and 1 ppb or less of uranium and thorium; and whose polymerization degree is 600 to 10000. Trialkoxysilane compounds or trichlorosilane compounds are hydrolyzed to produce a high-purity silicone ladder prepolymer whose polymerization degree is 5 to 600. The silicone ladder prepolymer is subjected to dehydrative condensation by using a nucleophilic reagent as a catalyst, and then purified in a dissolution/reprecipitation method to yield the silicone ladder polymer.