Method and compositions for printing substrates
View Patent ↗Processes and compositions for printing substrates. A printing paste containing a matrix-forming precondensate containing polyorganosiloxanes obtained by a sol-gel process and at least one coloring, luminescent, conductive and/or catalytically active filler is applied imagewise to the substrate and is densified by heat treatment at a temperature below the glass transition temperature of the matrix being formed. The processes and printing pastes are suitable, for example, for the production of conductor tracks and decorative patterns.
1. A process for the production of a printed substrate, which process comprises:
(i) image-wise applying to a substrate a printing paste comprising:
(a) a matrix-forming condensate which comprises polyorganosiloxanes, obtainable by a sol-gel process; and
(b) at least one filler selected from coloring fillers, luminescent fillers, conductive fillers and catalytically active fillers; and
(ii) densifying the image-wise applied paste to form a matrix which contains the at least one filler by a heat treatment at a temperature below the glass transition temperature of the thus-formed matrix.
2. The process of claim 1 , wherein the heat treatment is conducted at a temperature which is at least 200° C. below the glass transition temperature of the matrix.
3. The process of claim 1 , wherein the heat treatment is conducted at a temperature which is at least 400° C. below the glass transition temperature of the matrix.
4. The process of claim 3 , wherein the heat treatment is conducted at a temperature which is up to 700° C. below the glass transition temperature of the matrix.
5. The process of claim 2 , wherein the heat treatment is conducted at a temperature of form 400° C. to 800° C.
6. The process of claim 1 , wherein the printing paste is applied to the substrate by a process which comprises one of screen printing and pad printing.
7. The process of claim 1 , wherein the substrate comprises at least one of a glass substrate, a glass-ceramic substrate and a ceramic substrate.
8. The process of claim 7 , wherein the substrate comprises a conductive coating.
9. The process of claim 8 , wherein the conductive coating comprises at least one of tin oxide and indium tin oxide.
10. The process of claim 1 , wherein the printed substrate comprises at least one of conductor tracks, spacers and a decorative pattern.
11. The process of claim 10 , wherein the printed substrate comprises conductor tracks.
12. The process of claim 1 , wherein the at least one filler comprises a conductive filler.
13. The process of claim 1 , wherein the at least one filler comprises a catalytically active filler.
14. A composition comprising:
(a) a matrix-forming condensate which comprises polyorganosiloxanes, obtainable by a sol-gel process which comprises a partial hydrolysis and polycondensation of:
(A) at least one organosilane of formula R n SiX (4-n) , wherein each R independently represents a non-hydrolyzable group, each X independently represents a hydroxy group or a hydrolyzable group, and n represents 0, 1, 2 or 3; or an oligomer derived therefrom;
(B) optionally, at least one silane of formula SiX 4 , wherein X is as defined above, and
(C) optionally, one or more compounds of at least one of glass-forming elements and ceramic-forming elements;
(b) at least one filler selected from coloring fillers, luminescent fillers, conductive fillers and catalytically active fillers;
(c) at least one organic solvent having a boiling point of at least 150° C.; and
(d) at least one rheology control agent for providing structural viscosity or thixotropy.
15. The composition of claim 14 , wherein component (A) accounts for at least 40 mol %, based on the total of components (A) to (C).
16. The composition of claim 14 , wherein component (A) accounts for at least 60 mol %, based on the total of components (A) to (C).
17. The composition of claim 15 , wherein component (B) accounts for not more than 40 mol %, based on the total of components (A) to (C).
18. The composition of claim 14 , wherein the at least one filler comprises a conductive filler.
19. The composition of claim 18 , wherein the conductive filler is present in an amount of from 50 to 80% by weight.
20. The composition of claim 19 , wherein the conductive filler is present in an amount of from 70 to 75% by weight.
21. The composition of claim 14 , wherein the at least one filler comprises a coloring filler.
22. The composition of claim 14 , wherein the at least one filler comprises a luminescent filler.
23. The composition of claim 14 , wherein the at least one filler comprises a catalytically active filler.
24. The composition of claim 14 , wherein the at least one filler comprises at least one of a dye, a colored pigment, a photoluminescent substance, a electroluminescent substance, an electrically conductive material, a photoconductive material and a catalytically active material.
25. The composition of claim 14 , wherein the at least one filler comprises a particulate conductive material selected from gold, silver, copper, nickel, tungsten, molybdenum, tin oxide, indium tin oxide, lead zirconate titanate, graphite and combinations thereof.
26. The composition of claim 14 , wherein the composition is essentially free of glass particles.
27. The composition of claim 14 , wherein the at least one organic solvent comprises a solvent having a boiling point of at least 180° C.
28. The composition of claim 27 , wherein the at least one organic solvent is present in an amount of up to 50% by weight.
29. The composition of claim 14 , wherein the at least one rheology control agent comprises an organic rheology control agent.
30. The composition of claim 14 , wherein the at least one rheology control agent comprises at least one of a fish oil, a cellulose, a cellulose derivative and a polyalcohol.
31. The composition of claim 14 , wherein the at least one rheology control agent is present in an amount of not more than 5% by weight.
32. The composition of claim 30 , wherein the at least one rheology control agent is present in an amount of from 0.5% by weight to 2% by weight.
33. A composition comprising:
(a) a matrix-forming condensate which comprises polyorganosiloxanes, obtained by a sol-gel process which comprises a partial hydrolysis and polycondensation of:
(A) at least one organosilane of formula R n SiX (4-n) , wherein each R independently represents a non-hydrolyzable group, each X independently represents a hydroxy group or a hydrolyzable group, and n represents 0, 1, 2 or 3; or an oligomer derived therefrom;
(B) optionally, at least one silane of formula SiX 4 , wherein X is as defined above, and
(C) optionally, one or more compounds of at least one of glass-forming elements and ceramic-forming elements;
wherein component (A) accounts for at least 60 mol % of the total of components (A) to (C);
(b) at least one filler which comprises a particulate conductive material selected from gold, silver, copper, nickel, tungsten, molybdenum, tin oxide, indium tin oxide, lead zirconate titanate, graphite and combinations thereof;
(c) 1% by weight to 30% by weight of at least one organic solvent having a boiling point of at least 200° C.; and
(d) from 0.5% by weight to 2% by weight of a rheology control agent which comprises at least one of a fish oil, a cellulose, a cellulose derivative and a polyalcohol.