Treatment of filler with silane
View Patent ↗This invention relates to the treatment of a carbon based filler with a hydrolysable silane to modify the surface of the filler. It also relates to a carbon based filler modified by treatment with a hydrolysable silane, and to polymer compositions containing such a modified carbon based filler.
1. A process for modifying the surface of a carbon based filler by treatment with a hydrolysable silane, characterised in that the hydrolysable silane is a silane of the formula
wherein each R represents a hydrolysable group; each R″ represents a hydrocarbyl group having 1 to 8 carbon atoms; n=1 to 3; Y represents a divalent organic spacer linkage having 1 to 20 carbon atoms; X represents —O— or —NH—; m=0 or 1; R 2 represents hydrogen or a hydrocarbyl or substituted hydrocarbyl group having 1 to 8 carbon atoms; Z represents an oxygen or sulphur atom; R 3 represents a hydrocarbyl or substituted hydrocarbyl group having 1 to 20 carbon atoms; and R 1 represents a hydrocarbyl or substituted hydrocarbyl group having 1 to 20 carbon atoms.
2. A process according to claim 1 , characterised in that Z represents an oxygen atom and R 3 represents a hydrocarbyl group having 1 to 8 carbon atoms.
3. A process according to claim 1 , characterised in that Z represents an oxygen atom and R 3 represents a group of the formula —((CH2) a O) b —R 4 wherein a=1 to 3; b=1 to 6; and R 4 represents hydrogen or a hydrocarbyl or substituted hydrocarbyl group having 1 to 20 carbon atoms.
4. A process according to claim 1 , characterised in that Z represents a sulphur atom and R 3 represents a group of the formula —Y″—SiR p R″ 3-p wherein Y″ represents a divalent organic spacer linkage having 1 to 20 carbon atoms; each R represents a hydrolysable group; each R″ represents a hydrocarbyl group having 1 to 8 carbon atoms; and p=1 to 3.
5. A process according to claim 1 , characterised in that R 1 represents a hydrocarbyl group having 1 to 8 carbon atoms.
6. A process according to claim 1 , characterised in that that R 1 represents a group of the formula —Y*—SiR q R″ 3-q wherein Y* represents a divalent organic spacer linkage having 1 to 20 carbon atoms; each R represents a hydrolysable group; each R″ represents a hydrocarbyl group having 1 to 8 carbon atoms; and q=1 to 3.
7. A process according to claim 1 , characterised in that R 1 represents a group of the formula
wherein d=1 to 8; R 8 represents hydrogen or a hydrocarbyl or substituted hydrocarbyl group having 1 to 8 carbon atoms; Z represents an oxygen or sulphur atom; R 9 represents a hydrocarbyl or substituted hydrocarbyl group having 1 to 20 carbon atoms; X″ represents —O— or —NH—; m″=0 or 1; Y** represents a divalent organic spacer linkage having 1 to 20 carbon atoms; each R represents a hydrolysable group; each R″ represents a hydrocarbyl group having 1 to 8 carbon atoms; and r=1 to 3.
8. A process according to claim 1 , characterised in that R 1 represents a group of the formula —(CH2) e —C(O)OR 10 wherein e=1 to 8; and R 10 represents a hydrocarbyl group having 1 to 8 carbon atoms.
9. A process according to claim 1 , characterised in that R 2 represents hydrogen.
10. A process according to claim 1 , characterised in that each group R is an alkoxy group having 1 to 4 carbon atoms.
11. A process according to claim 10 , characterised in that each group R is an ethoxy group.
12. A process according to claim 1 , characterized in that n=3.
13. A process according to claim 1 , wherein the carbon based filler comprises carbon fibres.
14. A process according to claim 1 , wherein the carbon based filler is carbon black.
15. A process according to claim 1 , wherein the carbon based filler is selected from carbon nanotubes, fullerene, graphene and expandable graphene.
16. A process according to claim 1 , wherein a polymeric material, the carbon-based filler and the hydrolysable silane are heated together at a temperature of 120 to 200° C., whereby the polymeric material is crosslinked.
17. A carbon based filler modified by treatment with a hydrolysable silane of the formula
as defined according to claim 1 .
18. A filled polymer composition comprising an organosilicon polymer and a modified carbon based filler as defined in claim 17 .
19. A filled polymer composition comprising an organic polymer, a crosslinking agent containing organosilicon groups and a modified carbon based filler as defined in claim 17 .
20. A filled polymer composition comprising a polymer matrix, a modified carbon based filler as defined in claim 17 , and any other type of filler or fibre.