Coating compositions
The present invention relates to coating compositions comprising A) alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes, B) at least one crosslinking catalyst and optionally C) at least one alkoxysilane and D) optionally further auxiliaries and additives, where the fraction of the alkoxy groups is at least 10 wt %, based on the sum of components A) and C).
1. A coating composition comprising a mixture of
A) an alkoxy-functional arylpolysiloxane and/or alkoxy-functional aryl-alkylpolysiloxane comprising alkoxy groups;
B) a crosslinking catalyst selected from the group of the guanidines or amidines;
C) an alkoxysilane comprising alkoxy groups; and
D) optionally further auxiliaries and additives,
wherein the alkoxy groups is at least 10 wt %, based on the sum of components A) and C);
wherein the coating composition comprises from 10 to 70 wt % based on the mixture components A) and C) of alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes; and
from 0.001 to 15 wt % based on the mixture components A) and C) of the crosslinking catalyst; and C) from 10 to 80 wt % based on the mixture components A) and C); and
wherein the alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes are of the general formula (I):
R a Si(OR′) b O (4−a−b)/2 (I)
in which 0<a<2, 1<b<4 and a+b<4 and
R is selected from an aromatic moiety having 6 to 20 carbon atoms or from a mixture of an aromatic moiety having 6 to 20 carbon atoms and an alkyl group consisting of 1 to 8 carbon atoms, and
R′ is an alkyl group consisting of 1 to 8 carbon atoms,
wherein the coating composition has full mechanical and chemical stability resulting from a combination of physical volume drying of less than 6.5 hours under a pressure of 101325 Pa, with a temperature of 23° C., and with an ambient relative atmospheric humidity of approximately 40% and, at the same time, chemical crosslinking by hydrolysis-condensation with sufficient moisture introduced into the oven.
2. The coating composition according to claim 1 , wherein component A) comprises alkoxy-functional phenylpolysiloxanes.
3. The coating composition according to claim 2 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤4, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
4. The coating composition according to claim 1 , wherein component A) comprises alkoxy-functional phenylmethylpolysiloxanes.
5. The coating composition according to claim 4 , wherein the phenyl:methyl ratio is in the range from 1:0.1 to 0.1:1.
6. The coating composition according to claim 4 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤4, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
7. The coating composition according to claim 1 , wherein the alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes A) are present as solvent-free 100% resin or in the form of a resin solution.
8. The coating composition according to claim 7 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤4, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
9. The coating composition according to claim 1 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤2, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
10. The coating composition according to claim 9 , wherein component A) comprises alkoxy-functional phenylmethylpolysiloxanes.
11. The coating composition according to claim 9 , wherein the alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes A) are present as solvent-free 100% resin or in the form of a resin solution.
12. The coating composition according to claim 1 , wherein the crosslinking catalyst B) contains no silicon atoms.
13. The coating composition according to claim 1 , wherein the fraction of component B) in the coating composition is 0.1 to 15.0 wt %, based on component A).
14. The coating composition according to claim 1 , wherein the coating composition comprises further auxiliaries and additives as component D).
15. The coating composition according to claim 1 , wherein the coating composition comprises a fraction of component A) of 30 to 50 wt % based on the mixture components A) to C),
of component B) of 0.1 to 3.0 wt % based on the mixture components A) to C), and
of component C) of 20 to 50 wt % based on the mixture components A) to C).
16. A coating system comprising coating compositions according to claim 1 .
17. The coating systems according to claim 16 , wherein the coating system is a paint, an ink or a varnish.
18. The coating composition according to claim 1 , wherein the crosslinking catalyst B) is selected from the group of 1,1,3,3-tetramethylguanidine or 1,8diazabicyclo[5.4.0]-7-undecene.
19. The coating composition according to claim 1 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤4, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
20. A coating composition consisting of a mixture of
A) an alkoxy-functional arylpolysiloxane and/or alkoxy-functional aryl-alkylpolysiloxane comprising alkoxy groups;
B) a crosslinking catalyst selected from the group of the guanidines or amidines;
C) an alkoxysilane comprising alkoxy groups; and
D) auxiliaries and additives,
wherein the alkoxy groups is at least 10 wt %, based on the sum of components A) and C);
wherein the coating composition comprises from 10 to 70 wt % based on the mixture components A) and C) of alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes; and
from 0.001 to 15 wt % based on the mixture components A) and C) of the crosslinking catalyst; and C) from 10 to 80 wt % based on the mixture components A) and C); and
wherein the alkoxy-functional arylpolysiloxanes and/or alkoxy-functional aryl-alkylpolysiloxanes are of the general formula (I):
R a Si(OR′) b O (4−a−b)/2 (I)
in which 0<a<2, 1<b<4 and a+b<4 and
R is selected from an aromatic moiety having 6 to 20 carbon atoms or from a mixture of an aromatic moiety having 6 to 20 carbon atoms and an alkyl group consisting of 1 to 8 carbon atoms, and
R′ is an alkyl group consisting of 1 to 8 carbon atoms,
wherein the coating composition has full mechanical and chemical stability resulting from a combination of physical volume drying of less than 6.5 hours under a pressure of 101325 Pa, with a temperature of 23° C., and with an ambient relative atmospheric humidity of approximately 40%, and, at the same time, chemical crosslinking by hydrolysis-condensation with sufficient moisture introduced into the oven.
21. The coating composition according to claim 20 , wherein component A) is an alkoxy-functional phenylpolysiloxane.
22. The coating composition according to claim 20 , wherein component A) is an alkoxy-functional phenylmethylpolysiloxane.
23. The coating composition according to claim 22 , wherein the phenyl:methyl ratio is in the range from 1:0.1 to 0.1:1.
24. The coating composition according to claim 20 , wherein the alkoxy-functional arylpolysiloxane or alkoxy-functional aryl-alkylpolysiloxane A) are present as solvent-free 100% resin or in the form of a resin solution.
25. The coating composition according to claim 20 , wherein alkoxysilanes C) used are those of the formula (II)
R c Si(OR′) d (II)
0≤c≤2, 1≤d≤2, c+d=4
in which R is an alkyl group of 1 to 8 carbon atoms, a cycloalkyl group of 3 to 8 carbon atoms or an aromatic moiety having 6 to 20 carbon atoms and R′ is an alkyl group having 1 to 8 carbon atoms.
26. The coating composition according to claim 20 , wherein the crosslinking catalyst B) contains no silicon atoms.
27. The coating composition according to claim 20 , wherein the fraction of component B) in the coating composition is 0.1 to 15.0 wt %, based on component A).