Claims
- 1. A method for the production of a zirconia sol, which method comprises heating an aqueous solution of a zirconium salt in the presence of urea thereby forming a transparent zirconia sol, concentrating said zirconia sol with an ultrafilter membrane, and then subjecting the concentrated zirconia sol to thermal concentration at a temperature in the range of 5.degree. to 60.degree. C.
- 2. A method according to claim 1, wherein the temperature for heating the aqueous zirconium salt solution is in the range of 60.degree. to 300.degree. C.
- 3. A method according to claim 1, wherein the amount of urea is in the range of 0.2 to 4 mols, based on 1 mol of said zirconium salt.
- 4. A method according to claim 1, wherein said zirconium salt is zirconium nitrate.
- 5. A method according to claim 1, wherein said transparent zirconia sol incorporates therein a chelating agent and a compound of a metal other than zirconium.
- 6. A method according to claim 5, wherein the amount of said chelating agent is in the range of 0.02 to 1 mol based on 1 mol of zirconia in said sol and the amount of other metal compound is in the range of 0.5 to 20 mol %, based on the amount of zirconia.
- 7. A method according to claim 5, wherein said chelating agent is at least one member selected from the group consisting of oxyphenols, amino alcohols, oxyacids and esters thereof, oxyaldehydes, amino acids, .beta.-diketones, and .beta.-ketonic acids and esters thereof.
- 8. A method according to claim 5, wherein said chelating agent is at least one member selected from the group consisting of .beta.-diketones, .beta.-ketonic acids, and esters thereof.
- 9. A method according to claim 5, wherein said compound of a metal other than zirconium is a compound of at least one metal selected from the group consisting of yttrium, calcium, and magnesium.
- 10. A method according to claim 5, wherein said zirconium salt is zirconium nitrate.
Priority Claims (5)
Number |
Date |
Country |
Kind |
1-29672 |
Feb 1989 |
JPX |
|
1-124128 |
May 1989 |
JPX |
|
1-180182 |
Jul 1989 |
JPX |
|
1-209598 |
Aug 1989 |
JPX |
|
PCT/JP90/00162 |
Feb 1990 |
JPX |
|
Parent Case Info
This application is a continuation of application Ser. No. 07/582,838, filed Oct. 9, 1990 now abandoned.
US Referenced Citations (5)
Foreign Referenced Citations (9)
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253552 |
Jan 1988 |
EPX |
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Aug 1988 |
EPX |
60-018250 |
Jul 1983 |
JPX |
62-156946 |
Jul 1987 |
JPX |
62-275025 |
Nov 1987 |
JPX |
63-2809 |
Jan 1988 |
JPX |
63-222014 |
Sep 1988 |
JPX |
1171196 |
Nov 1969 |
GBX |
1234575 |
Jun 1971 |
GBX |
Continuations (1)
|
Number |
Date |
Country |
Parent |
582838 |
Oct 1990 |
|