Claims
- 1. A process for the production of a wet ceramic green part, which comprises:
- providing a castable, aqueous slip having slip particles therein, said slip particles having a surface charge;
- adding an active substance and an enzyme to the slip, wherein the enzyme is operative to decompose the active substance and wherein said active substance is a chemical which is decomposable due to a time delayed, enzymatically catalyzed reaction;
- thoroughly mixing and degassing the resultant slip;
- casting the thoroughly mixed and degassed slip into a mold to form a wet ceramic green part;
- waiting until decomposition products which change surface charge of the slip particles leading to solidification, are formed; and
- demolding the wet ceramic green part for drying and sintering.
- 2. The process of claim 1, wherein said active substance and enzyme are added separately to the slip.
- 3. The process of claim 1, wherein said active substance and enzyme are added to the slip as a mixture.
- 4. The process of claim 1, wherein said active substance is selected from the group consisting of urea, carboxylic acid esters, decomposable carbohydrates, esters of glycerol and carboxylic acid amides.
- 5. The process of claim 1, wherein said enzyme is selected from the group consisting of hydrolases and oxydases.
- 6. The process of claim 5, wherein said hydrolases are selected from the group consisting of urease, carboxylesterate, acetylestrase, pectinesterase, acylase, lipase and amidase.
- 7. The process of claim 5, wherein said oxydase is glucose oxidase.
- 8. The process of claim 1, including the step of further adding to said slip a polyacrylate emulsion which changes its structure due to a pH change from an acidic to an alkaline pH.
- 9. The process of claim 1, including the step of further adding to said slip a colloidal, inorganic sol which coagulates due to a pH change from an alkaline to an acidic pH.
- 10. The process of claim 9, wherein said colloidal inorganic sol is selected from the group consisting of silica, alumina, zirconia and titania particles with a medium particle size of 5-100 nm and a specific surface area of 20-400 m.sup.2 /g.
- 11. The process of claim 9, wherein said active substance is selected from the group consisting of urea, carboxylic acid esters, decomposable carbohydrates, esters of glycerol and carboxylic acid amides.
- 12. The process of claim 9, wherein said enzyme is selected from the group consisting of hydrolases and oxydases.
- 13. The process of claim 12, wherein said hydrolases are selected from the group consisting of urease, carboxylesterate, acetylestrase, pectinesterase, acylase, lipase and amidase.
- 14. The process of claim 12, wherein said oxydase is glucose oxidase.
- 15. The process of claim 1, wherein said active substance is a deflocculant and said enzyme is a deflocculant decomposing enzyme which is able to decompose the deflocculant due to a time delayed, enzymatically catalyzed reaction.
- 16. The process of claim 15, wherein said deflocculant 4,5-dihydroxy-1,3-benzenedisulfonic acid.
- 17. The process of claim 15, wherein said enzyme is catechol oxidase.
- 18. The process of claim 1, wherein said active substance includes non-deflocculating molecules and said enzyme is a deflocculant forming enzyme which is able to decompose the non-deflocculating molecules to a deflocculant due to a time delayed, enzymatically catalyzed reaction.
- 19. The process of claim 18, wherein said active substance includes derivatives of acetylsalicylic acid or precursors of citric acid.
- 20. The process of claim 18, wherein said enzyme is selected from the group consisting of arylester hydrolase and citrate synthase.
Parent Case Info
This application is a divisional of U.S. Ser. No. 08/624,715, filed Mar. 26, 1996 now U.S. Pat. No. 5,788,891, which in turn is a Continuation-In-Part of U.S. Ser. No. 08/211,139, filed May 9, 1994, now abandoned.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5188780 |
Lange et al. |
Feb 1993 |
|
Divisions (1)
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Number |
Date |
Country |
Parent |
624715 |
Mar 1996 |
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Continuation in Parts (1)
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Number |
Date |
Country |
Parent |
211139 |
May 1994 |
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