Claims
- 1. A sprayable room temperature vulcanizable coating composition prepared by a method comprising the steps of:
- (I) blending a particulate reinforcing filler with a non-reactive polyorganosiloxane oil under high shear conditions sufficient to reduce the filler particles to an average size less than about 300 nm in a time period of less than about 24 hours, to form a filler-oil masterbatch;
- (II) combining said masterbatch with at least one reactive polyorganosiloxane having a viscosity under ambient temperature and pressure conditions up to about 6,000 centipoise and effective amounts of at least one condensation catalyst and at least one crosslinking agent to form a coating composition having a viscosity under ambient temperature and pressure conditions up to about 10,000 centipoise.
- 2. A composition according to claim 1 wherein the filler is fumed silica or precipitated silica.
- 3. A composition according to claim 2 wherein the amount of filler is about 10-150 parts by weight per 100 parts of non-reactive silicone oil.
- 4. A composition according to claim 2 wherein the non-reactive polyorganosiloxane oil has the formula ##STR4## wherein each R.sup.1 is an alkyl radical and n has an average value such that the kinematic viscosity of said silicone oil is in the range of about 30-1,000 centipoise.
- 5. A composition according to claim 4 wherein each R.sup.1 is methyl.
- 6. A composition according to claim 2 wherein a treating agent for said filler is employed in step I.
- 7. A composition according to claim 6 wherein the treating agent is hexamethyidisilazane.
- 8. A composition according to claim 6 wherein the amount of treating agent is about 0.5-5% by weight based on filler and non-reactive silicone oil combined.
- 9. A composition according to claim 2 wherein the reactive silicone is a polydialkylsiloxane having the formula ##STR5## wherein each R.sup.2 is hydrogen or ##STR6## each R.sup.3 is independently a hydrocarbon or fluorinated hydrocarbon radical, each R.sup.4 and R.sup.5 is a hydrocarbon radical, a is 0 or 1 and m has a value such that the viscosity of said reactive silicone under ambient temperature and pressure conditions is up to about 6,000 centipoise.
- 10. A composition according to claim 9 wherein each R.sup.3 is methyl.
- 11. A composition according to claim 10 wherein each R.sup.2 is hydrogen.
- 12. A composition according to claim 10 wherein each R.sup.2 is methyl and water is also present in said composition.
- 13. A composition according to claim 2 wherein the condensation catalyst is a tin, zirconium or titanium compound.
- 14. A composition according to claim 2 wherein crosslinking agent is a trifunctional or tetrafunctional silane.
- 15. A composition according to claim 14 wherein the crosslinking agent is a tetraalkyl silicate.
- 16. An article comprising a marine structure coated with an anti-fouling coating which is the condensation cured reaction product of a sprayable room temperature vulcanizable coating composition prepared by a method comprising the steps of:
- (I) blending a particulate reinforcing filler with a non-reactive polyorganosiloxane oil under high shear conditions sufficient to reduce the filler particles to an average size less than about 300 nm in a time period of less than about 24 hours, to form a filler-oil masterbatch;
- (II) combining said masterbatch with at least one reactive polyorganosiloxane having a viscosity under ambient temperature and pressure conditions up to about 6,000 centipoise and effective amounts of at least one condensation catalyst and at least one crosslinking agent to form a coating composition having a viscosity under ambient temperature and pressure conditions up to about 10,000 centipoise.
- 17. An article according to claim 16 wherein the marine structure is a ship's hull.
- 18. An article according to claim 16 wherein the non-reactive polyorganosiloxane oil has the formula ##STR7## wherein each R.sup.1 is methyl and n has an average value such that the kinematic viscosity of said silicone oil is in the range of about 30-1,000 centipoise.
- 19. An article according to claim 16 wherein the reactive silicone is a polydialkylsiloxane having the formula ##STR8## wherein each R.sup.2 is hydrogen or ##STR9## each R.sup.3, R.sup.4 and R.sup.5 is methyl, a is 0 or 1 and m has a value such that the viscosity of said reactive silicone under ambient temperature and pressure conditions is up to about 6,000 centipoise.
- 20. An article according to claim 16 wherein the condensation catalyst is a tin, zirconium or titanium compound and the crosslinking agent is a tetraalkyl silicate.
Government Interests
This invention was made with government support under Contract No. N61533-93-C-0062 awarded by the Department of the Navy. The government has certain rights in this invention.
US Referenced Citations (1)
Number |
Name |
Date |
Kind |
5563210 |
Donatelli et al. |
Oct 1996 |
|
Foreign Referenced Citations (1)
Number |
Date |
Country |
2287248 |
Feb 1995 |
GBX |