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:
Feb. 16, 1999
Filed:
Feb. 03, 1997
Kouichi Takei, Tsukuba, JP;
Youichi Machii, Tsukuba, JP;
Toshikatsu Shimazaki, Tsukuba, JP;
Hiroki Terasaki, Tsukuba, JP;
Hidekuni Banno, Tsukuba, JP;
Yutaka Honda, Tsuchiura, JP;
Nobuaki Takane, Tsukuba, JP;
Hitachi Chemical Company, Ltd., Tokyo, JP;
Abstract
A silica glass production process that can prevent cracks from occurring during the step of gel drying. In a process for producing silica glass, comprising the steps of subjecting a partial polycondensation product of alkoxysilane to hydrolysis in the presence of a solvent, an organic polymeric compound and a basic catalyst to form a sol, making the sol into a gel, drying the gel to form a dry gel, and firing the dry gel to obtain a glass, a salt is caused to exist in a concentration not less than 1.times.10.sup.-4 mol based on 100 g of the partial polycondensation product of alkoxysilane in the step of subjecting the partial polycondensation product of alkoxysilane to hydrolysis to form a sol.