Solid silicone defoamer

Claim 2

A solid silicone defoamer comprising (A) 5 to 60 parts by weight of a self-emulsifying defoaming agent being a mixture of: (i) at least 5 weight % of silicone oil having a viscosity of at least 20 centistokes at 25 degrees Centigrade and microparticulate silica, and (ii) at least 30 weight % of a material selected from the group consisting of polyoxyalkylene and polyoxyalkylene/polysiloxane copolymers, (B) 95 to 40 parts by weight of wax; said wax being selected from the group consisting of: (i) a water-insoluble wax which is insoluble in water at room temperature and which has a melting point of at least 35 degrees Centigrade, and (ii) a water-soluble wax which dissolves and disperses in water at room temperature and which has a melting point of at least 30 degrees Centigrade; and wherein wax (i) is present at less than 60 weight % of the defoamer.

Claim 3

The defoamer of claim 1 also including in (A) 1 to 30 weight % of a water soluble surfactant.

Claim 4

The defoamer of claim 1 in which the component (A) (ii) is a compound selected from the group consisting of polyoxypropylene polymers, polyoxypropylene/polyoxyethylene copolymers, and compounds with general formulas (1)-(4): R.sub.a Si[(OSiMe.sub.2).sub.n (OSiMeG).sub.b OSiMe.sub.2 G].sub.4-a( 1) R.sub.a Si[(OSiMe.sub.2).sub.n (OSiMeG).sub.c OSiMe.sub.3 ].sub.4-a( 2) GMe.sub.2 Si(OSiMe.sub.2).sub.n (OSiMeG).sub.b OSiMe.sub.2 G(3) Me.sub.3 Si(OSiMe.sub.2).sub.n (OSiMeG).sub.c OSiMe.sub.3, (4) wherein: R is a hydrocarbon group having one to ten carbon atoms but without aliphatic unsaturation; Me is methyl; G is a group with the structural formula --D(OR') m A in which D is an alkylene group having one through thirty carbon atoms, R' is an alkylene group having 2 through 10 carbon atoms, m has a value of at least 1, and A is a terminal group; a is one; n has a value of at least one; b has a value of 1-50; and c has a value of 1-50.

Claim 5

The defoamer of claim 2 wherein the component (A) (ii) is a liquid with an HLB number of at least nine and being a compound selected from the group consisting of polyoxyethylene alkylphenyl ethers, polyoxyethylene sorbitan fatty acid esters, polyglycerin fatty acid esters, polyoxyethylene alkyl ethers, polyoxyethylene castor oil, and polyoxyethylene hardened castor oil.