High performance silicon-based compositions
Provided herein are silicon-based compositions, which after curing is a coating composition having strong substrate adhesion and scratch resistance. The compositions are formed from a mixture of constituents comprising: from about 20% to about 90% (w/w) of a first siloxane selected from the group consisting of silsesquioxane, methylmethoxysiloxane, and combinations thereof; and from about 10% to about 80% (w/w) of one or more silicon compounds selected from the group consisting of a second siloxane, silane, and silazane. Optionally, the compositions may comprise from about 0.1% to about 5% (w/w) alkyltitanate.
1. A silicon-based composition, which after curing is a coating composition having strong substrate adhesion, scratch resistance, and solvent resistance, the composition formed from a mixture of constituents comprising:
from about 20% to about 90% (w/w, of the total composition) of a first siloxane consisting of methylsilsesquioxane and an α, ω methoxy-terminated polydimethylsiloxane, wherein the α, ω methoxy-terminated polydimethylsiloxane is at least 10% (w/w, of the total composition); and
from about 10% to about 80% (w/w, of the total composition) of one or more silicon compounds selected from the group consisting of a second siloxane, silane, and silazane.
2. The composition of claim 1 , wherein the first siloxane consists of from about 10% to about 70% (w/w, of the total composition) methylsilsesquioxane and from about 10% to about 50% (w/w, of the total composition) α, ω methoxy-terminated polydimethylsiloxane.
3. The composition of claim 1 , further comprising from about 0.1% to about 5% (w/w, of the total composition) alkyltitanate.
4. The composition of claim 3 , wherein the alkyltitanate comprises butyltitanate present in an amount ranging from about 0.5% to about 2% (w/w, of the total composition).
5. The composition of claim 3 , comprising one or more silicon compounds from about 10% to about 50% (w/w, of the total composition).
6. The composition of claim 3 , comprising silane selected from the group consisting of trimethoxysilane, triethoxysilane, aminopropylsilane, and polysilane.
7. The composition of claim 3 , wherein the one or more silicon compounds comprises methylphenylsilicone resin.
8. The composition of claim 1 , wherein
the silicon compound comprises a combination of from about 10% to about 50% (w/w, of the total composition) triethoxysilane, and from about 10% to about 20% (w/w, of the total composition) methylphenylsilicone resin; and
an alkyltitanate comprising from about 0.5% to about 2% (w/w, of the total composition) butyltitanate.
9. A polymer formed from the polymerization of a mixture comprising a first siloxane consisting of methylsilsesquioxane and α, ω-methoxy-terminated polydimethylsiloxane; and one or more silicon compounds selected from the group consisting of a second siloxane, silane, and silazane;
the polymer comprising:
a siloxane ladder structure comprising a repeating unit of formula (I),
wherein each R 1 is hydrocarbyl, and wherein n is between 4 and 100.
10. The polymer of claim 9 , wherein R 1 is alkyl.
11. The polymer of claim 9 , wherein R 1 is methyl.
12. A compound comprising formula (II),
wherein:
each R 1 is hydrocarbyl;
each R 2 is alkyl;
each A is selected from the group consisting of
each R 3 is selected from the group consisting of alkyl and SiH(OR 4 ) 2 ;
each R 4 is selected from the group consisting of methyl and ethyl;
n is between 4 and 100; and
x, y, and z are each between 1 and 100.
13. The compound of claim 12 , wherein each R 1 is methyl.
14. The compound of claim 12 , wherein each R 2 is butyl.
15. The compound of claim 12 , wherein x, y, and z are each between 5 and 25.
16. The compound of claim 12 , wherein the compound of formula (II) comprises a compound of formula (III):
17. A method of coating a surface, which method comprises:
(a) mixing silicon-based constituents to form a silicon-based coating composition comprising:
from about 20% to about 90% (w/w, of the total composition) of a first siloxane consisting of methylsilsesquioxane and α, ω methoxy-terminated polydimethylsiloxane, wherein the α, ω methoxy-terminated polydimethylsiloxane is at least 10% (w/w, of the total composition); and
from about 10% to about 80% (w/w, of the total composition) of one or more silicon compounds selected from the group consisting of a second siloxane, silane, and silazane;
(b) coating the mixture onto a surface; and
(c) curing the coating at a temperature from about 20° C. to about 400° C. for about 0.3 hours to about 5 hours.
18. The method of claim 17 , wherein the first siloxane consists of from about 10% to about 70% (w/w, of the total composition) methylsilsesquioxane and from about 10% to about 50% (w/w, of the total composition) α, ω methoxy-terminated polydimethylsiloxane; and wherein, the silicon compound comprises a combination of from about 10% to about 50% (w/w, of the total composition) triethoxysilane, and from about 10% to about 20% (w/w, of the total composition) methylphenylsilicone resin.
19. The method of claim 17 , wherein the silicon-based coating composition further comprises from about 0.1% to about 5% (w/w, of the total composition) alkyltitanate.
20. The method of claim 19 , wherein the alkyltitanate comprises from about 0.5% to about 2% (w/w, of the total composition) butyltitanate.
21. The method of claim 17 , wherein the coating is cured at a temperature of about 300° C. to about 400° C. for about 0.3 hours to about 5 hours to form the coating composition.