Fillers, pigments and mineral powders treated with organopolysiloxanes
View Patent ↗A filler, pigment or mineral powder surface treated with a silicon compound is described. The silicon compound is a polydiorganosiloxane having at least one terminal group of the formula —SiR″(OR′) 2 or —Si(OR′) 3 , wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms. The filler, pigment or mineral powder treated is hydrophobic and is used in composites or industrial processes.
1. A filler, pigment or mineral powder surface treated by chemical interaction with a silicon compound, wherein the silicon compound is a polydiorganosiloxane having at least two terminal groups of the formula —SiR″(OR′) 2 , wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms, wherein the polydiorganosiloxane has a vapour pressure lower than 2000 Pa at 25° C.
2. The treated filler, pigment or mineral powder according to claim 1 wherein R″ represents an alkyl group having 3 to 8 carbon atoms.
3. The treated filler, pigment or mineral powder according to claim 1 wherein the degree of polymerisation of the polydiorganosiloxane is 4 to 250 siloxane units.
4. The treated filler, pigment or mineral powder according to claim 1 wherein the polydiorganosiloxane is derived from the reaction of a hydroxyl-terminated polydiorganosiloxane with an alkoxysilane of the formula R″Si(OR′) 3 in the presence of a catalyst for the condensation of silanol groups with Si-alkoxy groups, wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms.
5. The treated filler, pigment or mineral powder according to claim 1 wherein the polydiorganosiloxane is a linear polydiorganosiloxane.
6. The treated filler, pigment or mineral powder according to claim 1 wherein the polydiorganosiloxane is a branched polydiorganosiloxane.
7. The treated filler, pigment or mineral powder according to claim 6 wherein the polydiorganosiloxane contains branching sites derived from the reaction of a molecule of an alkoxysilane of the formula R″Si(OR′) 3 with at least 3 silanol groups of a hydroxyl-terminated polydiorganosiloxane, wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms.
8. The treated filler, pigment or mineral powder according to claim 6 wherein the polydiorganosiloxane contains branching sites derived from the reaction of a hydroxyl-terminated polydiorganosiloxane with an alkoxysilane of the formula R″Si(OR′) 3 in the presence of a branched organosilicon resin and a catalyst for the condensation of silanol groups with Si-alkoxy groups, wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms.
9. The treated filler, pigment or mineral powder according to claim 6 wherein the polydiorganosiloxane contains branching sites derived from the reaction of a branched hydroxyl-terminated polydiorganosiloxane with an alkoxysilane of the formula R″Si(OR′) 3 , wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms.
10. A process for the surface treatment of a filler, pigment or mineral powder with a silicon compound, wherein the silicon compound is a polydiorganosiloxane having at least two terminal groups of the formula —SiR″(OR′) 2 , wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms, wherein the surface treatment includes chemical interaction between the surface and the silicon compound, and wherein the polydiorganosiloxane has a vapour pressure lower than 2000 Pa at 25° C.
11. The process according to claim 10 , wherein the filler, pigment or mineral powder is treated with a mixture of the polydiorganosiloxane and an aminosilane or aminosiloxane.
12. The process according to claim 10 , wherein the filler, pigment or mineral powder is treated with a mixture of the polydiorganosiloxane and a nonlinear organosilicon resin containing Si—OH groups or Si-alkoxy groups.
13. A plastics or rubber composition wherein the plastics o rubberr contains the filler or pigment as claimed in claim 1 .
14. A process for producing a plastics or rubber composition wherein the filler or pigment as claimed in claim 1 is mixed with a plastics or rubber matrix material.
15. A process for producing a plastics or rubber composition, wherein an organic plastics or rubber matrix material is mixed with a filler or pigment and a polydiorganosiloxane having at least two terminal groups of the formula —SiR″(OR′) 2 , wherein R″ represents an alkyl, substituted alkyl, alkenyl or aryl group and each R′ represents an alkyl group having 1 to 4 carbon atoms, wherein a surface of the filler or pigment is treated by chemical interaction with the polydiorganosiloxane, and wherein the polydiorganosiloxane has a vapour pressure lower than 2000 Pa at 25° C.
16. The treated filler, pigment or mineral powder according to claim 1 wherein R″ represents propyl, vinyl, aminopropyl, phenyl, methacryloxypropyl, or glycidoxypropyl, and wherein R′ represents methyl or ethyl.
17. The treated filler, pigment or mineral powder according to claim 1 wherein the treated filler, pigment or mineral powder is hydrophobic.
18. The treated filler, pigment or mineral powder according to claim 1 , wherein R″ represents propyl, haloalkyl, aminopropyl, phenylmethyl, vinylbenzylethylenediaminepropyl, methacryloxypropyl, or glycidoxypropyl.