Marine foulant release coating

Claim 1

A ship's hull normally immersed in sea water and coated with an outermost coating of a curable silicone rubber composition comprising: (1) 100 parts of a liquid vinyl chain-stopped polysiloxane having the formula: (CH.sub.2 ═CH)R.sub.2 SiO--[R'.sub.2 SiO].sub.n --R.sub.2 Si(CH═CH.sub.2) where R and R' are monovalent hydrocarbon radicals free of aliphatic unsaturation, with at least 50 mole percent of the R' groups being methyl and where n has a value sufficient to provide a viscosity of from about 2,500 to 750,000 centistokes at 25° C., (2) from 20 to 50 parts of an organopolysiloxane copolymer comprising (R") 3 SiO 0 .5 units and SiO 4/2 units, where R" is a member selected from the class consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of (R") 3 SiO 0 .5 units to SiO 4/2 units is from about 0.5:1 to 1:1, and where from about 2.5 to 10 mole percent of the silicon atoms contain silicon-bonded vinyl groups, (3) from 1 to 200 parts of a finely divided inorganic filler which is non-reinforcing for silicone elastomers, (4) a platinum catalyst, (5) an amount of a liquid organohydrogen polysiloxane having the formula: (R).sub.a (H).sub.b SiO.sub.(4-a-b)/2 sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atom per silicon-bonded vinyl group in the composition, where R is as previously defined, a has a value of from 1.00 to 2.00, b has a value of from about 0.1 to 1.0, and the sum of a plus b is from about 2.00 to 2.67, there being at least two silicon-bonded hydrogen atoms per molecule.

Claim 8

A method for reducing foul on ships comprising the step of coating the ship's hull with a outermost coating of a curable silicone rubber composition comprising: (1) 100 parts of a liquid vinyl chain-stopped polysiloxane having the formula: (CH.sub.2 ═CH)R.sub.2 SiO--[R'.sub.2 SiO].sub.n --R.sub.2 Si(CH═CH.sub.2) where R and R' are monovalent hydrocarbon radicals free of aliphatic unsaturation, with at least 50 mole percent of the R' groups being methyl and where n has a value sufficient to provide a viscosity of from about 2,500 to 750,000 centistokes at 25° C., (2) from 20 to 50 parts of an organopolysiloxane copolymer comprising (R") 3 SiO 0 .5 units and SiO 4/2 units, where R" is a member selected from the class consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of (R") 3 SiO 0 .5 units to SiO 4/2 units is from about 0.5:1 to 1:1, and where from about 2.5 to 10 mole percent of the silicon atoms contain silicon-bonded vinyl groups, (3) from 1 to 200 parts of a finely divided inorganic filler which is non-reinforcing for silicone elastomers, (4) a platinum catalyst, (5) an amount of a liquid organohydrogen polysiloxane having the formula: (R).sub.a (H).sub.b SiO.sub.(4-a-b)/2 sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atom per silicon-bonded vinyl group in the composition, where R is as previously defined, a has a value of from 1.00 to 2.00, b has a value of from about 0.1 to 1.0, and the sum of a plus b is from about 2.00 to 2.67, there being at least two silicon-bonded hydrogen atoms per molecule.

Claim 9

A method for reducing foul on ships comprising the step of coating the ship's hull with a outermost coating of a curable silicone rubber composition comprising: (1) 100 parts of a liquid vinyl chain-stopped polysiloxane having the formula: (CH.sub.2 ═CH)R.sub.2 SiO--[R'.sub.2 SiO].sub.n --R.sub.2 Si(CH═CH.sub.2) where R and R' are monovalent hydrocarbon radicals free of aliphatic unsaturation, with at least 50 mole percent of the R' groups being methyl and where n has a value sufficient to provide a viscosity of from about 2,500 to 750,000 centistokes at 25° C., (2) from 20 to 50 parts of an organopolysiloxane copolymer comprising (R") 3 SiO 0 .5 units and SiO 4/2 units, where R" is a member selected from the class consisting of vinyl radicals and monovalent hydrocarbon radicals free of aliphatic unsaturation, where the ratio of (R") 3 SiO 0 .5 units to SiO 4/2 units is from about 0.5:1 to 1:1, and where from about 2.5 to 10 mole percent of the silicon atoms contain silicon-bonded vinyl groups, (3) from 1 to 200 parts of a finely divided inorganic filler which is non-reinforcing for silicone elastomers, (4) a platinum catalyst, (5) an amount of a liquid organohydrogen polysiloxane having the formula: (R).sub.a (H).sub.b SiO.sub.(4-a-b)/2 sufficient to provide from about 0.5 to 1.0 silicon-bonded hydrogen atom per silicon-bonded vinyl group in the composition, where R is as previously defined, a has a value of from 1.00 to 2.00, b has a value of from about 0.1 to 1.0, and the sum of a plus b is from about 2.00 to 2.67, there being at least two silicon-bonded hydrogen atoms per molecule.