| 摘要 |
PURPOSE:To obtain silica glass not causing cracking or crazing by adding polyvinyl acetate to a solvent contg. 1-methyl-2-pyrrolidone, hydrolyzing silicon alkoxide in the solvent, converting the resulting silica sol into gel, drying and sintering the gel. CONSTITUTION:Polyvinyl acetate is added to a solvent (e.g., methanol) contg. 1-methyl-2-pyrrolidone and silicon alkoxide such as silicon tetramethoxide is hydrolyzed in the solvent in the presence of a catalyst, preferably a base catalyst. The resulting silica sol is allowed to stand, e.g., at 0-100 deg.C for several min to several ten days to form silica gel. This gel is allowed to stand at room temp.-200 deg.C for several hr to several ten days until it is dried and the dry gel is sintered by heating to 1,000-1,400 deg.C at 50-400 deg.C/hr heating rate in a proper atmosphere to obtain silica glass. This silica glass can easily be produced at a low cost and can be used in various fields of optics, semiconductor industry, electronic industry, etc. |
