Durable coating compositions and coatings formed thereof
A durable coating composition which reduces ice adherence and minimizes ice accumulation includes a silicate binder, a silane-modified filler, a film forming lubricant, and a crosslinking agent. Articles and overhead conductors coated with such coating compositions are also disclosed.
1. A coating composition comprising:
a silicate binder;
a hydrophobically-modified filler comprising an average particle size of about 20 microns or less and a dielectric constant of about 20 or less;
a film forming lubricant comprising a hydrophobic polymer dispersion; wherein the hydrophobic polymer dispersion comprises one or more of an acrylic resin dispersion and a polyurethane resin dispersion; and
a crosslinking agent comprising one or more of magnesium hydroxide and magnesium oxide.
2. The coating composition of claim 1 , wherein the silicate binder comprises an alkali metal silicate.
3. The coating composition of claim 2 , wherein the alkali metal silicate comprises one or more of potassium silicate, sodium silicate, lithium silicate, and calcium silicate.
4. The coating composition of claim 1 , wherein the hydrophobically-modified filler comprises a hydrophobically-modified metal oxide.
5. The coating composition of claim 4 , wherein the hydrophobically-modified metal oxide comprises one or more of alumina, silica, magnesium silica, silicon carbide, calcined clay, zirconium dioxide, and zirconium silicate.
6. The coating composition of claim 5 , wherein the hydrophobically-modified metal oxide is hydrophobically modified by a silane compound comprising one or more of octyl trimethoxy silane, methyl trimethoxy silane, phenyl trimethoxy silane, and dimethyl dichloro silane.
7. The coating composition of claim 1 , wherein each of the acrylic resin dispersion and the polyurethane resin dispersion are hydrophobically modified by a reactive functional silicone intermediate.
8. The coating composition of claim 1 , further comprising water.
9. The coating composition of claim 1 comprises, on a dry weight basis: about 10% to about 50% of the silicate binder; about 30% to about 70% of the silane-modified filler; about 5% to about 30% of the film forming lubricant; and about 2% to about 20% of the crosslinking agent.
10. The coating composition of claim 1 having two parts; wherein the first part comprises the silane-modified filler, the film forming lubricant, and the crosslinking agent; and wherein the second part comprises the silicate binder.
11. An overhead conductor comprising a bare conductor substantially coated with a coating formed from the coating composition of claim 1 .
12. The overhead conductor of claim 11 passes a 0.5 inch Mandrel Bend Test.
13. The overhead conductor of claim 11 passes a 0.5 inch Mandrel Bend Test after heat aging at 200° C. for 7 days.
14. The overhead conductor of claim 11 operates about 5° C. or cooler when tested in accordance to ANSI C119.4-2004 than the bare conductor.
15. The overhead conductor of claim 11 , wherein ice adheres with about 140 kPa or less of force according to the Ice Adherence Test.
16. The overhead conductor of claim 11 exhibits a water contact angle of about 50° to about 140°.
17. The overhead conductor of claim 11 , exhibits an increase in ice adherence strength after water aging at about 90° C. for 7 days of about 50% or less compared to the ice adherence strength of an unaged coated overhead conductor.
18. The overhead conductor of claim 11 , exhibits an increase in ice adherence strength after heat aging at about 200° C. for 30 days of about 50% or less compared to the ice adherence strength of an unaged coated overhead conductor.
19. An article comprising a substrate substantially coated with a coating formed from the coating composition of claim 1 .