Silicone-polyester copolymer and process for preparing same

Claim 1

THE PROCESS OF MAKING A HOMOGENEOUS SILICONEPOLYESTER COPOLYMER COMPOSITION WHICH COMPRISES (A) STRIPPING A REACTION MIXTURE OF (1) AN ALIPHATIC ESTER AND ALCOHOL-CONTAINING SOLUTION OF 70 TO 95% BY WEIGHT, BASED ON THE WEIGHT OF SAID COPOLYMER, OF THE HYDROLYSIS PRODUCT OF A MIXTURE OF ORGANOCHLOROSILANES HAVING AN AVERAGE OF FROM ABOUT 1.0 TO 1.75 ORGANIC GROUPS PER SILICON ATOM AND (2) FROM 30 TO 5% BY WEIGHT, BASED ON THE WEIGHT OF SAID COPOLYMER, OF A POLYESTER MATERIAL HAVING A VISCOSITY OF BETWEEN ABOUT 38,000 CENTIPOISES TO 42,000 CENTIPOISES AT 25*C. AND (B) THEREAFTER HEATING THE RESULTING STRIPPED PRODUCT AT A PRESSURE BELOW ABOUT 100 MILLIMETERS AT A TEMPERATURE FROM ABOUT 175*C. TO ABOUT 200*C., THE ORGANO GROUPS OF SAID ORGANOCHLOROSILANES BEING ATTACHED TO SILICON THROUGH CARBON-SILICON LINKAGES AND BEING SELECTED FROM THE CLASS CONSISTING OF LOWER ALKYL GROUPS, ARYL GROUPS, HALOGENATED ARYL GROUPS AND MIXTURES THEREOF, SAID POLYESTER MATERIAL COMPRISING THE REACTION PRODUCT OF (A) FROM 25 TO 60 EQUIVALENT PERCENT OF A LOWER DIALKYL ESTER OF A MEMBER SELECTED FROM THE CLASS CONSISTING OF ISOPHTHALIC ACID, TEREPHTHALIC ACID AND MIXTURES THEREOF, (B) FROM 10 TO 50 EQUIVALENT PERCENT OF ETHYLENE GLYCOL, AND (C) FROM 20 TO 60 EQUIVALENT PERCENT OF A SATURATED ALIPHATIC POLYHYDRIC ALCOHOL HAVING AT LEAST 3 HYDROXYL GROUPS.