Method of preparing unsaturated polyester resins from alkylene oxides and ethylenically unsaturated dicarboxylic acid anhydrides

Claim 1

A PROCESS WHICH COMPRISES: (A) REACTING TOGETHER, AT TEMPERATURES IN THE RANGE OF 30* TO 150*C., (1) A SUBSTANCE SELECTED FROM THE GROUP CONSISTING OF MALEIC ACID ANHYDRIDE AND MIXTURES OF MALEIC ACID ANHYDRIDE WITH ANHYDRIDES OF OTHER DICARBOXYLIC ACIDS, SAID MIXTURES CONTAINING AT LEAST 10 MOL PERCENT OF MALEIC ACID ANHYDRIDE, WITH (2) AN ALKYLENE OXIDE SELECTED FROM THE GROUP CONSISTING OF ETHYLENE, PROPYLENE, AND BUTYLENE OXIDES AND MIXTURES OF SAID OXIDES IN THE PRESENCE OF (A) FROM 0 TO 5.0%, BASED ON THE WEIGHT OF THE REACTION MIXTURE, OF A CATALYST SELECTED FROM THE GROUP CONSISTING OF ALKALI METAL SALTS, ALKALI METAL HYDROXIDES, ALKALINE EARTH METAL SALTS, ALKALINE EARTH METAL HYDROXIDES, SALTS OF ORGANIC AMINES AND HYDROXIDES OF ORGANIC AMINES, AND (B) FROM 0 TO 4 GRAM MOLS OF WATER PER 1000 GRAMS OF (1) AND (2), THE MINIMUM TOTAL AMOUNT OF SAID CATALYST AND SAID WATER BEING AT LEAST .0075 GRAM MOL PER 1000 GRAM OF (1) AND (2), UNTIL SAID ALKYLENE OXIDE IS SUBSTANTIALLY COMPLETELY REACTED AND A PRODUCT HAVING AN ACID NUMBER OF FROM ABOVE 40 TO 240 IS OBTAINED; AND (B) THEREAFTER, HEAT TREATING SAID PRODUCT AS THE SOLE REACTIVE MEDIUM AT A TEMPERATURE OF FROM ABOUT 180* TO 250*C.