1421461 Hydrophobic silica and calcium silicate STAUFFER CHEMICAL CO 1 Jan 1973 [30 Dec 1971] 28/73 Heading C1A [Also in Division C3] Fumed silica (Example 12) and precipitated calcium polysilicate (Example 13) are rendered hydrophobic by heating with 5-methoxy-hexamethyltrisiloxan-1-ol....