Non-aqueous silica sols and method for preparing same

Claim 2

A NON-AQUEOUS SILICA SOL CONSISTING ESSENTIALLY OF, AS THE CONTINUOUS PHASE, A WATER MISCIBLE NONOHYDRIC ALCOHOL HAVING A BOILING POINT GREATER THAN 50*C., AND AS THE DISPERSED PHASE 20-60% BY WEIGHT OF COLLOIDAL, DISCRETE DENSE PARTICLES OF SALT-FREE SILICA WHICH HAVE AN AVERAGE PARTICLE DIAMETER OF 5-150 MILLIMICRONS, AND A SPECIFIC SURFACE AREA OF AT LEAST 20 M.2/G., WHICH SILICA PARTICLES HAVE FROM ABOUT 50% TO ABOUT 95% OF THEIR SURFACE SILANOL GROUPS HYDROGEN BONDED BY AN ORGANIC WATER MISCIBLE HYDROGEN BONDING AGENT AND FROM ABOUT 5% TO ABOUT 50% OF THEIR SURFACE SILANOL GROUPS ESTERIFIED WITH THE SAME WATER MISCIBLE ALCOHOL WHICH CORRESPONDS TO THE CONTINUOUS PHASE, SAID HYDROGEN BONDING AGENT HAVING A DIPOLE MOMENT OF AT LEASE 3.0 DEBYE UNITS, AND BEING PRESENT IN A MOL RATIO PER MOL OF HYDROGEN BONDED AND SURFACE ESTERIFIED SILANOL GROUPS OF FROM 10:1 TO 1:1.

Claim 3

THE PROCESS OF PRODUCING A NON-AQUEOUS SILICA SOL WHICH COMPRISES THE STEPS OF ADDING AN ORGANIC WATER MISCIBLE HYDROGEN BONDING AGENT WHICH HAS A DIPOLE MOMENT OF AT LEAST 3.0 DEBYE UNITS TO AN AQUEOUS SALTFREE SILICA SOL CONTAINING FROM 20% TO 60% BY WEIGHT OF SILICA TO FORM A REACTION SYSTEM, WITH THE AMOUNT OF HYDROGEN BONDING AGENT BEING APRESENT IN A MOL RATIO PER MOL OF SURFACE SILANOL GROUPS PRESENT IN THE SILICA PARTICLES OF THE SILICA SOL OF FROM 10:1 TO 1:1, ADDING UNDER VACUUM TO THE REACTION SYSTEM A WATER MISCIBLE MONOHYDRIC ALCOHOL IN AN AMOUNT OF FROM 1 TO 7 VOLUMES PER VOLUME OF WATER PRESENT IN THE AQUEOUS SALT-FREE SILICA SOL, SAID ALCOHOL HAVING A BOILING KPOINT GREATER THAN 50*C., MAINTAINING SAID VACUUM AND HEATING THE REACTANTS UNDER CONDITIONS WHEREBY SUBSTANTIALLY ALL THE WATER IS REMOVED FROM THE REACTION SYSTEM, RELEASING THE VACUUM, HEATING THE WATER MISCIBLE ALCOHOL OF THE FORMED NON-AQUEOUS SILICA SOL CONTAINING 20-60% BY WEIGHT OF SILICA TO ITS REFLUX TEMPERATURE AT AMBIENT PRESSURE AND MAINTAINING SAID TEMPERATURE FOR AT LEAST 1/4 HOUR.

Claim 4

THE PROCESS OF PRODUCING A NON-AQUEOUS SILICA SOL WHICH COMPRISES THE STEPS OF ADDING AN ORGANIC WATER MISCIBLE HYDROGEN BONDING AGENT WHICH HAS A DIPOLE MOMENT OF AT LEAST 3.0 DEBYE UNITS TO AN AQUEOUS SALTFREE SILICA SOL CONTAINING FROM 20% TO 60% BY WEIGHT OF SILICA TO FORM A REACTION SYSTEM, WITH THE AMOUNT OF HYDROGEN BONDING AGENT BEING APRESENT IN A MOL RATIO PER MOL OF SURFACE SILANOL GROUPS PRESENT IN THE SILICA PARTICLES OF THE SILICA SOL OF FROM 10:1 TO 1:1, ADDING UNDER VACUUM TO THE REACTION SYSTEM A WATER MISCIBLE MONOHYDRIC ALCOHOL IN AN AMOUNT OF FROM 1 TO 7 VOLUMES PER VOLUME OF WATER PRESENT IN THE AQUEOUS SALT-FREE SILICA SOL, SAID ALCOHOL HAVING A BOILING KPOINT GREATER THAN 50*C., MAINTAINING SAID VACUUM AND HEATING THE REACTANTS UNDER CONDITIONS WHEREBY SUBSTANTIALLY ALL THE WATER IS REMOVED FROM THE REACTION SYSTEM, RELEASING THE VACUUM, HEATING THE WATER MISCIBLE ALCOHOL OF THE FORMED NON-AQUEOUS SILICA SOL CONTAINING 20-60% BY WEIGHT OF SILICA TO ITS REFLUX TEMPERATURE AT AMBIENT PRESSURE AND MAINTAINING SAID TEMPERATURE FOR AT LEAST 1/4 HOUR.