US4246143A
Expired / Lapsed
US
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Process of preparing conductive tin dioxide powder
Assignee: Panasonic Holdings Corp
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Filing: 1979-07-11
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Granted: 1981-01-20
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Expires: 1999-07-11
Abstract
Abstract A process of preparing a conductive tin dioxide powder doped with 0.001-2.0 mole % of antimony oxide by heating a mixture of stannous oxalate and an antimony compound, preferably a halide, to form tin dioxide through thermal decomposition of stannous oxalate and accomplish firing of the formed tin dioxide without causing sintering. Preferably the mixture is prepared by using a solution of an antimony halide, followed by evaporation of the solvent. This process gives a tin dioxide powder low in specific resistance for the dopant concentration, high in whiteness and small in particle size.
Inventors
- 👤 Nobuo Sonoda
- 👤 Wataru Shimotsuma
- 👤 Shigeru Tsubusaki
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 10:08
CPC Classifications
G; G03; G03G; G03G5/00; G03G5/02; G03G5/0202; C; C01; C01G; C01G19/00; C01G19/02; G03G5/04; G03G5/05; G03G5/0528; G03G5/0589; G03G5/0592; G03G5/10; G03G5/104
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
143 words
A process of preparing a conductive tin dioxide powder, comprising the steps of: (a) preparing a mixture of stannous oxalate and an antimony compound; and (b) heating said mixture in an oxidizing atmosphere to form tin dioxide through thermal decomposition of said stannous oxalate by maintaining the heating temperature within the range from about 400° C. to about 550° C. during an initial stage until completion of thermal decomposition of said stannous oxalate and thereafter raising the heating temperature to a temperature within the range from about 700° C. to 1300° C. to accomplish firing of an intermediate mixture obtained by the initial stage heating; the proportion of said antimony compound to said stannous oxalate in the step (a) being made such that a tin dioxide powder obtained through the step (b) is doped with 0.001-2.0 mole% of Sb 2 O 5 .
Claim 2
Dependent Claim
143 words
A process of preparing a conductive tin dioxide powder, comprising the steps of: (a) preparing a mixture of stannous oxalate and an antimony compound; and (b) heating said mixture in an oxidizing atmosphere to form tin dioxide through thermal decomposition of said stannous oxalate by maintaining the heating temperature within the range from about 400° C. to about 550° C. during an initial stage until completion of thermal decomposition of said stannous oxalate and thereafter raising the heating temperature to a temperature within the range from about 700° C. to 1300° C. to accomplish firing of an intermediate mixture obtained by the initial stage heating; the proportion of said antimony compound to said stannous oxalate in the step (a) being made such that a tin dioxide powder obtained through the step (b) is doped with 0.001-2.0 mole% of Sb 2 O 5 .
Claim 3
Dependent Claim
25 words
A process according to claim 1, wherein said intermediate mixture is stirred before raising of the heating temperature after completion of the initial stage heating.
Claim 4
Dependent Claim
46 words
A process according to claim 1, wherein the initial stage heating in the step (b) is performed by placing said mixture prepared in the step (a) in a vessel, heating said vessel by an open fire and simultaneously and continuously stirring said mixture in said vessel.
Claim 5
Dependent Claim
171 words
A process of preparing a conductive tin dioxide powder, comprising the steps of: (a) preparing a mixture of stannous oxalate and an antimony compound; and (b) heating said mixture in an oxidizing atmosphere to form tin dioxide through thermal decomposition of said stannous oxalate by maintaining the heating temperature within the range from about 400° C. to about 550° C. during an initial stage until completion of thermal decomposition of said stannous oxalate, then raising the heating temperature and maintaining the heating temperature within the range from about 450° C. to about 700° C. to calcine an intermediate mixture obtained by the initial stage heating and finally further raising the heating temperature to a temperature within the range from about 700° C. to 1300° C. to accomplish firing of the calcined intermediate; the proportion of said antimony compound to said stannous oxalate in the step (a) being made such that a tin dioxide powder obtained through the step (b) is doped with 0.001-2.0 mole % of Sb 2 O 5 .
Claim 6
Dependent Claim
171 words
A process of preparing a conductive tin dioxide powder, comprising the steps of: (a) preparing a mixture of stannous oxalate and an antimony compound; and (b) heating said mixture in an oxidizing atmosphere to form tin dioxide through thermal decomposition of said stannous oxalate by maintaining the heating temperature within the range from about 400° C. to about 550° C. during an initial stage until completion of thermal decomposition of said stannous oxalate, then raising the heating temperature and maintaining the heating temperature within the range from about 450° C. to about 700° C. to calcine an intermediate mixture obtained by the initial stage heating and finally further raising the heating temperature to a temperature within the range from about 700° C. to 1300° C. to accomplish firing of the calcined intermediate; the proportion of said antimony compound to said stannous oxalate in the step (a) being made such that a tin dioxide powder obtained through the step (b) is doped with 0.001-2.0 mole % of Sb 2 O 5 .
Claim 7
Dependent Claim
46 words
A process according to claim 4, wherein the initial stage heating in the step (b) is performed by placing said mixture prepared in the step (a) in a vessel, heating said vessel by an open fire and simultaneously and continuously stirring said mixture in said vessel.
Claim 8
Dependent Claim
29 words
A process according to claim 5, wherein said intermediate mixture is stirred before raising of the heating temperature after completion of the initial stage heating in the step (b).
Claim 9
Dependent Claim
16 words
A process according to claims 1, or 4, wherein said antimony compound is an antimony halide.
Claim 10
Dependent Claim
20 words
A process according to claim 7, wherein said mixture in the step (a) is prepared by a wet mixing method.
Claim 11
Dependent Claim
45 words
A process according to claim 7, wherein said mixture in the step (a) is prepared by immersing stannous oxalate in a solution of said antimony halide in a solvent, stirring said stannous oxalate immersed in said solution and thereafter evaporating said solvent from said solution.
Claim 12
Dependent Claim
32 words
A process according to claim 7, wherein said mixture in the step (a) is prepared by dissolving both stannous oxalate and said antimony halide in a solvent and thereafter evaporating said solvent.
Claim 13
Dependent Claim
48 words
A process according to claim 1 or 4, wherein the proportion of said antimony compound to said stannous oxalate in the step (a) is made such that a tin dioxide powder obtained through the step (b) is doped with 0.1-0.3 mole % of Sb 2 O 5 .
References Cited (Backward Citations)
US3502597A
Cited
JPS515300A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1984-01-20 | 1984-07-21 | 1985-01-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1988-01-20 | 1988-07-21 | 1989-01-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1992-01-20 | 1992-07-21 | 1993-01-20 | $7700.00 | Window Closed / Lapsed |