Title:
PROCESS FOR PRODUCING QUARTZ GLASS
Document Type and Number:
WIPO Patent Application WO/1984/002519
Kind Code:
A1
Abstract:
A process for synthesizing poreless quartz glass at low temperatures, which comprises uniformly dispersing, in a sol solution prepared by hydrolyzing a metal alkoxide, 0.2 to 5 mol, per mol of the metal alkoxide, of superfine silica powder to gel, drying the obtained gel and sintering the dried gel. This process makes possibel the production of quartz glass of a practical size at low cost which has been believed to be impossible by the conventional sol-gel process. A larger dry gel can be obtained by adjusting the pH to 3 to 6 with a base. The yield of the dry gel can be improved by controlling the opening ratio of the lid of the sol solution-retaining vessel to 50% or less upon gelling and preparation of the dry gel, setting the gelling temperature at 5 to 60oC and the drying temperature at 20 to 120oC, and controlling the temperture-raising rate (from the gelling temperature to the drying temperature) at 120oC/hr or less. Further the yield upon sintering and the quality of the resulting quartz glass can be improved by raising the temperature upon sintering the dry gel to a predetermined temperature between 20 and 400oC at a rate of 400oC/hr or less, conducting the treatment of holding the gel at the same temperature for one hour or longer at least once to remove absorbed water, then raising the temperature to a predetermined temperature of 400 to 1100oC at a rate of 30 to 400oC/hr, conducting the treatment of holding it at the same temperature for 3 hours or longer at least once to remove carbon, then raising the temperature to a predetermined temperature between 1000 and 1400oC at a rate of 30 to 400oC/hr to remove any pores.
More Like This:
| JPH01153537 | PRODUCTION OF CERAMICS |
| JPS6465031 | PRODUCTION OF GLASS |
| JPS61178426 | PRODUCTION OF QUARTZ GLASS |
Inventors:
TOKI MOTOYUKI (JP)
KANBE SADAO (JP)
MIYASHITA SATORU (JP)
TAKEUCHI TETSUHIKO (JP)
KANBE SADAO (JP)
MIYASHITA SATORU (JP)
TAKEUCHI TETSUHIKO (JP)
Application Number:
PCT/JP1983/000450
Publication Date:
July 05, 1984
Filing Date:
December 22, 1983
Export Citation:
Assignee:
SUWA SEIKOSHA KK (JP)
International Classes:
C03B8/02; C03B19/12; C03B20/00; C03C1/00; C03C1/02; C03C3/06; (IPC1-7): C03C1/02; C03C3/06; C03B20/00
Foreign References:
| JPS56125240A | 1981-10-01 | |||
| JPS5722129A | 1982-02-05 | |||
| JPS5722130A | 1982-02-05 | |||
| JPS5826048A | 1983-02-16 |
Other References:
SAKUKA SUMIO "Glass Hishoshitsu no Kagaku" 30 June 1983 (30. 06. 83) Uchida Rokakuho Kabushiki Kaisha p147-p164
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