| abstract |
A process for making a master silica mixture, comprising the steps of: (a) treating a suspension of silica in water, or in a solution of water and an alcohol containing at least 70% water, with a methoxy silane , or a mixture of methoxy silanes, to give a hydrophobicized silica; wherein the methoxy silane or mixture of methoxy silanes, or its reaction product with water, is soluble in alcohol / water mixtures containing at least 70% water; (b) combining the hydrophobicized silica with a latex and optionally with other compounding ingredients such as process oils, before coagulation; (c) coagulate the latex - mixture of hydrophobicized silica with calcium chloride; (d) dehydrate the clotted clump; and (e) dry the dehydrated lump. |