Pyrolysis resistant coating finish
View Patent ↗A coating solution made from a mixture of at least one silane and at least one polysiloxane which can be hardened on a substrate by hydrolysis and condensation to give a coating on the substrate, wherein the at least one silane is of general formula RxSi(OR′)4-x and the at least one polysiloxane is of general formula [R2SiO]y or R3Si—(O—SiR2)Y—O—SiR3, where R independently=alkyl, aryl, arylalkyl, alkylaryl or H, Rprime independently=H, methyl, ethyl, n- or i-propyl, n-, iso-, sec.- or tert.-butyl, x=0 or 1 (for the first silane), x=0, 1, 2, 3 or 4 (for each further silane) and y=a whole number of at least 2, wherein the coating solution includes at least one alkali or earth alkali oxide or hydroxide.
1. A coating solution for forming a hardened pyrolysis resistant coating finish based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2;
the coating solution comprising at least one alkali or alkaline-earth metal containing reagent selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide;
wherein the ratio of the silane and polysiloxane mixture to the alkali or alkaline-earth metal containing reagent, referred to the atomic ratio Si:alkali/alkaline-earth metal, is 20:1 to 5:1.
2. The coating solution according to claim 1 wherein x is 1 for the first silane.
3. The coating solution according to claim 1 wherein the coating solution further comprises colorants.
4. The coating solution according to claim 3 wherein the temperature-resistant inorganic pigments are mica-based and provide a metallic visual appearance.
5. The coating solution according to claim 1 wherein the coating solution further comprises solvents wherein the boiling temperature of the solvent is greater than that of ethanol.
6. The coating solution according to claim 1 wherein R′ is at least one of methyl or ethyl.
7. The coating solution according to claim 1 wherein the at least one silane is at least one of methyltriethoxysilane or tetraethoxysilane.
8. The coating solution according claim 1 wherein the alkali or alkaline-earth metal containing reagent is NaOH or KOH.
9. The coating solution according to claim 1 wherein R and R′ are independently at least one of methyl or ethyl and x=1.
10. The coating solution according to claim 9 wherein R=methyl, R′=ethyl, the alkali or alkaline-earth metal containing reagent is KOH and x=1.
11. The coating solution according to claim 9 wherein R=methyl, R′=ethyl, the alkali or alkaline-earth metal containing reagent is NaOH and x=1.
12. The coating solution according to claim 1 wherein the coating solution contains an aluminum compound.
13. The coating solution according to claim 1 wherein the coating solution contains nanoscale SiO 2 particles.
14. A method for producing a coating solution for forming a hardened pyrolysis resistant coating finish, the method comprising:
(a) prepare at least one silane of the general formula R X Si(OR′) 4-X alone or with at least one polysiloxane of the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 , wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each further silane); and
y is an integer which is at least 2;
and mix if necessary;
(b) add an alkali/alkaline-earth oxide/hydroxide to the silane or mixture set forth in step (a);
(c) if required, add a colorant to the mixture in/from step (b); and
(d) if required, add an aluminum compound to the mixture set forth in at least one of step (b) and (c);
wherein the ratio of the silane and polysiloxane mixture to the alkali or alkaline-earth metal containing reagent, referred to the atomic ratio Si:alkali/alkaline-earth metal, is 20:1 to 5:1.
15. A coating which is a hardened pyrolysis resistant coating finish on a metal substrate, the coating being obtained by application, drying, densification and firing-on of the coating solution, the coating comprising a coating solution based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2; and
at least one alkali or alkaline-earth metal containing reagent is selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide;
wherein the ratio of the silane and polysiloxane mixture to the alkali or alkaline-earth metal containing reagent, referred to the atomic ratio Si:alkali/alkaline-earth metal, is 20:1 to 5:1.
16. A bi- or multilayer coating, obtained by applying at least two different coating solutions, the coating comprising at least two layers wherein each layer includes a coating solution based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2; and at least one alkali or alkaline-earth metal containing reagent is selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide.
17. A component of a cooking appliance comprising a component body and a coating disposed on the component body wherein the coating includes a coating solution based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2; and
at least one alkali or alkaline-earth metal containing reagent is selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide.
18. The coating solution according to claim 3 wherein the colorants comprises temperature-resistant inorganic pigments.
19. The coating solution according claim 1 wherein the atomic ratio Si:alkali/alkaline-earth metal, is 15:1 to 10:1.
20. The coating solution according claim 1 wherein the atomic ratio Si:alkali/alkaline-earth metal, is 12:1 to 11:1.
21. A coating solution based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2;
the coating solution comprising at least one alkali or alkaline-earth metal containing reagent selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide;
wherein the coating solution contains an aluminum compound; and
wherein the aluminum compound comprises an aluminum alkoxide.
22. A method for producing a coating solution for forming a hardened pyrolysis resistant coating finish, the method comprising:
(a) prepare at least one silane of the general formula R X Si(OR′) 4-X alone or with at least one polysiloxane of the general formula [R 2 SiO] y or R 3 Si—(O—SiR 2 ) y —O—SiR 3 , wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each further silane); and
y is an integer which is at least 2;
and mix if necessary;
(b) add an alkali/alkaline-earth oxide/hydroxide to the silane or mixture set forth in step (a);
(c) if required, add a colorant to the mixture in/from step (b); and
(d) add an aluminum compound to the mixture set forth in at least one of step (b) and (c).
23. A coating solution based on a mixture of at least one silane and at least one polysiloxane curable by hydrolysis and condensation on a substrate to thereby produce a coating on the substrate, the least one silane having the general formula R X Si(OR′) 4-X and the at least one polysiloxane having the general formula R 3 Si—(O—SiR 2 ) y —O—SiR 3 wherein
the residues R are independently alkyl, aryl, arylalkyl, alkylaryl or H;
the residues R′ are independently H, methyl, ethyl, n- or i-propyl, n-, iso-, sec- or tert-butyl;
x=0 or 1 (for the first silane);
x=0, 1, 2, 3 or 4 (for each additional silane); and
y is an integer which is at least 2;
the coating solution comprising at least one alkali or alkaline-earth metal containing reagent selected from the group consisting of alkali oxide, alkali hydroxide, alkaline earth oxide, and alkaline earth hydroxide.