Process for producing silicone resins of controlled hydroxyl content

Claim 1

THE METHOD FOR PREPARING A SILICONE RESIN OF A PREDETERMINED SILICON-BONDED HYDROXYL CONTENT WHICH COMPRISES HYDROLYZING AND CONDENSING AT LEAST ONE SILANE HAVING MONOVALENT HYDROCARBON AND READILY-HYDROLYZABLE RADICALS ATTACHED TO THE SILICON ATOM THEREOF TO A PARTIALLY CONDENSED HYDROXYL-CONTAINING SILICONE HYDROLYZATE CONTAINING A RATIO OF MONOVALENT HYDROCARBON RADICALS TO SILICON ATOMS OF FROM ABOUT 0.05:1.0 TO ABOUT 1.7:1.0, SUFFICIENT WATER BEING EMPLOYED IN THE HYDROLYSIS TO HYDROLYZE ALL THE READILY-HYDROLYZABLE RADICALS, FURTHER CONDENSING SAID HYDROLYZATE TO A POLYMER RELATIVELY FREE OF SILICON-BONDED HYDROXYL GROUPS BY HEATING A SOLUTION OF SAID HYDROLYZATE IN AN INERT SOLVENT WITH SODIUM HYDROXIDE CATALYST TO A POINT WHERE NO FURTHER CONDENSATION OCCURS, SAID SODIUM HYDROXIDE CATALYST BEING PRESENT IN AN AMOUNT TO IMPART A MINIMUM PH OF APPROXIMATELY 8 TO THE SOLUTION, NEUTRALIZING SAID POLYMER SOLUTION, AND HEATING A NEUTRAL SOLUTION OF SAID POLYMER IN AN INERT SOLVENT IN THE PRESENCE OF WATER, SAID WATER BEING PRESENT IN AN AMOUNT OF FROM ABOUT ONE-ELEVENTH TO ABOUT ONEFOURTH OF THE WEIGHT OF POLYMER PRESENT, TO A TEMPERATURE OF FROM AT LEAST ABOUT 250*C. TO ABOUT 400*C. UNDER A PRESSURE OF FROM AT LEAST ABOUT 400 P.S.I. TO ABOUT 20,000 P.S.I., IN ORDER TO REINTRODUCE SILICON-BONDED HYDROXYL GROUPS INTO THE STRUCTURE OF SAID POLYMER RELATIVELY FREE OF SILICON-BONDED HYDROXYL GROUPS, SAID HEATING BEING CONTINUED UNTIL EQUILIBRIUM HAS BEEN ATTAINED.

Claim 2

THE METHOD FOR PREPARING A SILICONE RESIN OF A PREDETERMINED SILICON-BONDED HYDROXYL CONTENT WHICH COMPRISES HYDROLYZING AND CONDENSING AT LEAST ONE SILANE HAVING MONOVALENT HYDROCARBON AND READILY-HYDROLYZABLE RADICALS ATTACHED TO THE SILICON ATOM THEREOF TO A PARTIALLY CONDENSED HYDROXYL-CONTAINING SILICONE HYDROLYZATE CONTAINING A RATIO OF MONOVALENT HYDROCARBON RADICALS TO SILICON ATOMS OF FROM ABOUT 0.05:1.0 TO ABOUT 1.7:1.0, SUFFICIENT WATER BEING EMPLOYED IN THE HYDROLYSIS TO HYDROLYZE ALL THE READILY-HYDROLYZABLE RADICALS, FURTHER CONDENSING SAID HYDROLYZATE TO A POLYMER RELATIVELY FREE OF SILICON-BONDED HYDROXYL GROUPS BY HEATING A SOLUTION OF SAID HYDROLYZATE IN AN INERT SOLVENT WITH SODIUM HYDROXIDE CATALYST TO A POINT WHERE NO FURTHER CONDENSATION OCCURS, SAID SODIUM HYDROXIDE CATALYST BEING PRESENT IN AN AMOUNT TO IMPART A MINIMUM PH OF APPROXIMATELY 8 TO THE SOLUTION, NEUTRALIZING SAID POLYMER SOLUTION, AND HEATING A NEUTRAL SOLUTION OF SAID POLYMER IN AN INERT SOLVENT IN THE PRESENCE OF WATER, SAID WATER BEING PRESENT IN AN AMOUNT OF FROM ABOUT ONE-ELEVENTH TO ABOUT ONEFOURTH OF THE WEIGHT OF POLYMER PRESENT, TO A TEMPERATURE OF FROM AT LEAST ABOUT 250*C. TO ABOUT 400*C. UNDER A PRESSURE OF FROM AT LEAST ABOUT 400 P.S.I. TO ABOUT 20,000 P.S.I., IN ORDER TO REINTRODUCE SILICON-BONDED HYDROXYL GROUPS INTO THE STRUCTURE OF SAID POLYMER RELATIVELY FREE OF SILICON-BONDED HYDROXYL GROUPS, SAID HEATING BEING CONTINUED UNTIL EQUILIBRIUM HAS BEEN ATTAINED.