Unsaturated polyester flexible films

Claim 1

A FLEXIBLE FILM OF A COPOLYMER CONSISTING ESSENTIALLY, BY WEIGHT, OF (1) 30 TO 60 PERCENT COPOLYMERIZABLE COMPOUND CONTAINING THE POLYMERIZABLE GROUP CH2=C<; AND (2) 40 TO 70 PERCENT UNSATURATED POLYESTER WHICH IS THE CONDENSATION PRODUCT OF (A) A PHTHALIC ACID MATERIAL SELECTED FROM THE GROUP CONSISTING OF IOSPHTHALIC ACID, TEREPHTHALIC ACID, AND ESTERS OF ISOPHTHALIC ACID AND TEREPHTHALIC ACID AND A LOWER MONOHYDRIC ALCOHOL; (B) AN UNSATURATED DICARBOXYLIC ACID MATERIAL SELECTED FROM THE GROUP CONSISTING OF A,B-ETHYLENICALLY UNSATURATED DICARBOXYLIC ACIDS, AND THEIR ANHYDRIDES; AND (C) A BLEND OF AT LEAST TWO GLYCOLS, AT LEAST ONE OF WHICH IS A POLYALKYLENE GLYCOL, SAID GLYCOLS BEING SELECTED FROM THE GROUP CONSISTING OF ETHYLENE GLYCOL, PROPYLENE GLYCOL, BUTYLENE GLYCOL, POLYETHYLENE GLYCOL, POLYPROPYLENE GLYCOL, AND POLYBUTYLENE GLYCOL, SAID BLEND OF GLYCOLS HAVING AN AVERAGE MOLECULAR WEIGHT IN THE RANGE 120 TO 300, ANY SINGLE GLYCOL SPECIES OF SAID BLEND NOT EXCEEDING A MOLECULAR WEIGHT OF 1,000; SAID PHTHALIC ACID MATERIAL BEING EMPLOYED IN THE RANGE 1 TO 5 MOLS PER MOL OF UNSATURATED DICARBOXYLIC ACID MATERIAL, AND SAID GLYCOLS IN AN AMOUNT SUFFICIENT TO NEUTRALIZE THE CARBOXYL GROUPS UP TO A 5 MOL PERCENT STOICHIOMETRIC EXCESS; SAID ESTER HAVING AN ACID NUMBER BELOW ABOUT 30.