Ceramic mediums and inks in powder form
The disclosure relates to printing mediums, useful for ceramic sinterable materials, that are in powder form and are based on glycols, urea and an inorganic absorbent, to ceramic inks compositions comprising the printing mediums and to methods for decorating green or fired ceramic bodies by the use of said printing mediums and compositions.
1. A composition comprising:
a) from about 5 to about 50% wt of an inorganic absorbent,
b) from about 10 to about 50% wt of a glycol,
c) from about 20 to about 70% wt of urea, and
d) from about 0.1% to about 10% of a rheology modifier; wherein the composition is in the form of a powder.
2. The composition of claim 1 wherein the inorganic absorbent is present at a concentration of from about 10 to about 30% wt; the glycol is present at a concentration of from 15 to 40% wt; and the urea is present at a concentration of from about 30 to about 60% wt.
3. The composition of claim 1 additionally comprising up to about 15% wt of conventional organic components used in preparing ceramic printing mediums selected from the group consisting of binders, plasticizers, preservative agents, anti-foam agents, dispersants, water retention agents and combinations thereof.
4. The composition of claim 1 wherein the inorganic absorbent is selected from the group consisting of precipitated silica, silica gel, calcium silicates, alumina, aluminates, clays and combinations thereof.
5. The composition of claim 4 wherein the inorganic absorbent is precipitated silica.
6. The composition of claim 1 wherein the glycol is selected from the group consisting of monopropylene glycol (MPG), dipropylene glycol (DPG), monoethylene glycol (MEG), diethylene glycol (DEG), polyethylene glycol having average molecular weight of less than about 5,000 (PEG), and combinations thereof.
7. The composition of claim 6 wherein the glycol is monoethylene glycol.
8. A ceramic ink powder comprising from about 30 to about 80% wt of ceramic pigments and from about 20 to about 70% wt of a concentrated ceramic medium wherein the concentrated ceramic medium comprises:
a) from about 5 to about 50% wt of on inorganic absorbent,
b) from about 10 to about 50% wt of a glycol,
c) from about 20 to about 70% wt of urea, and
d) from about 0.1% to about 10% of a rheology modifier; and wherein the concentrated ceramic medium is a powder.
9. A method for decorating green or fired ceramic bodies comprising:
dispersing a concentrated ceramic medium comprising:
a) from about 5 to about 50% wt of an inorganic absorbent,
b) from about 10 to about 50% wt of a glycol,
c) from about 20 to about 70% wt of urea, and
d) from about 0.1% to about 10% of a rheology modifier,
in water to form a liquid ceramic medium in powder form;
preparing a ceramic ink composition by mixing ceramic pigments with the liquid ceramic medium;
applying a glaze to the surface of the green or fired ceramic bodies;
applying the ceramic ink to the surface of the green or fired ceramic bodies; and
firing the green or fired ceramic bodies.
10. The method of claim 9 wherein the concentrated ceramic medium is dispersed in water at a wt-part ratio of concentrated ceramic medium to water of from about 1:1 to about 2:1.
11. The method of claim 9 wherein the wt-part ratio of ceramic pigments to liquid ceramic medium is from about 20:80 to about 80:20.
12. The method of claim 11 wherein the wt-part ratio of ceramic pigments to liquid ceramic medium is from about 30:70 to about 70:30.
13. The method of claim 9 wherein the green or fired ceramic body upon which the ceramic ink has been applied is fired at a temperature of from about 900 ° C. to about 1250 ° C. for from about 15 to about 240 minutes.
14. The method of claim 11 wherein the liquid ceramic ink composition is prepared by homogenizing 30 to 80 parts by weight of ceramic pigments and from 20 to 70 parts by weight of the concentrated ceramic medium.
15. The method of claim 14 wherein the ceramic pigments and the concentrated ceramic medium are homogenized in a turbine mixer or in a mill.
16. The method of claim 9 wherein the inorganic absorbent is present at a concentration of from about 10 to about 30% wt; the glycol is present at a concentration of from 15 to 40% wt; and the urea is present at a concentration of from about 30 to about 60% wt.
17. The method of claim 9 wherein the concentrated ceramic medium additionally comprises up to about 15% wt of conventional organic ingredients used in preparing ceramic printing mediums selected from the group consisting of binders, plasticizers, preservative agents, anti-foam agents, dispersants, water retention agents and combinations thereof.
18. The method of claim 9 wherein the inorganic absorbent is selected from the group consisting of precipitated silica, silica gel, calcium silicates, alumina, aluminates, clays and combinations thereof.
19. The method of claim 18 wherein the inorganic absorbent is precipitated silica.
20. The method of claim 9 wherein the glycol is selected from the group consisting of monopropylene glycol (MPG), dipropylene glycol (DPG), monoethylene glycol (MEG), diethylene glycol (DEG), polyethylene glycol having average molecular weight of less than about 5,000 (PEG), and combinations thereof.
21. The method of claim 20 wherein the glycol is monoethylene glycol.