carbon atoms with one or more polycarboxylic acids having from 2 to 14 carbon atoms examples of suitable polyhydric alcohols include ethylene glycol propylene glycol such as 1 2 propylene glycol and 1 3 propylene glycol glycerol pentaerythritol trimethylolpropane 1 4 6 octanetriol butanediol pentanediol hexanediol dodecanediol octanediol chloropentanediol glycerol monallyl ether glycerol monoethyl ether diethylene glycol 2 ethylhexanediol 1 4 cyclohexanediol 1 4 1 2 6 hexanetriol 1 3 5 hexanetriol 1 3 bis 2 hydroxyethoxy propane and the like examples of polycarboxylic acids include phthalic acid isophthalic acid terephthalic acid tetrachlorophthalic acid maleic acid dodecylmaleic acid octadecenylmaleic acid fumaric acid aconitic acid trimellitic acid tricarballylic acid 3 3 u2032 thiodipropionic acid succinic acid adipic acid malonic acid glutaric acid pimelic acid sebacic acid cyclohexane 1 2 dicarboxylic acid 1 4 cyclohexadiene 1 2 dicarboxylic acid 3 methyl 3 5 cyclohexadiene 1 2 dicarboxylic acid and the corresponding acid anhydrides acid chlorides and acid esters such as phthalic anhydride phthaloyl chloride and the dimethyl ester of phthalic acid preferred polycarboxylic acids are the aliphatic and cycloaliphatic dicarboxylic acids containing no more than 14 carbon atoms and the aromatic dicarboxylic acids containing no more than 14 atoms commercially available polyols which may be used in the practice of the invention include polyethers such as arcol ppg 2025 bayer polyg 20 56 arch and pluracol p 2010 basf polyesters such as dynacoll 7360 creanova fomrez 66 32 crompton and rucoflex s 105 30 bayer and polybutadiene such as poly bd r 45htlo elf atochem a most preferred polyol is polyoxypropylene polyoxyethylene non.