| 主权项 |
1. A granular pumice comprising:
a surface coated with a hydrophobic coating; wherein the coating comprises a silane or a siloxane; wherein the silane is:
A1) a silane of the general formula:
R3—Si—(OR2)3;where:
R2 is a methyl or ethyl radical; andR3 is:
an alkyl radical having from 3 to 12 carbon atoms; oran aminoalkyl radical having from 1 to 6 carbon atoms; ora radical of the general formula
H2N—(CH2)xR4—(CH2)y—,where:
R4 is an oxygen, sulfur, —NH—, or—NH—CH2—CH2—NH— radical;x≧2; andy≧2; ora radical of the general formula:
(R2O)3Si—(CH2)x—NH—(CH2)x—, where R2 and x are as defined above;where n is an integer from 1 to 5,
wherein the siloxane is:
A2) a siloxanol of the general formula:where:
R5 is a methyl or phenyl radical, with at least 90% of the radicals R5 being methyl radicals; andm=20 to 250. |
