Patent ID: 8703838

Claim:
An unsaturated polyester prepared from the polycondensation of unsaturated diacid monomers or unsaturated diacid anhydride monomers selected from maleic acid, maleic acid anhydride, fumaric acid, itaconic acid, or mixtures thereof, and polyol monomers selected from ethylene glycol, 1,2-propanediol, 1,3-propanediol, 2-methyl-1,3-propanediol, 2,2,-dimethyl-1,3-propanediol (neopentyl glycol), 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 2,2,4-trimethyl-1,3-pentanediol, 2-butyl,2-ethyl-1,3-propanediol, diethylene glycol, triethylene glycol, dipropylene glycol, 1,4-cyclohexanedimethanol, 1,3-cyclohexanedimethanol, glycerol, trimethylolpropane, trimethylol ethane, or mixtures thereof, and, optionally, one or more saturated aliphatic or aromatic diacid monomers or anhydride monomers thereof, the improvement comprising: 0.5 to 5 weight percent, based on the total monomer weight, of an hydroxyalkyl-functional siloxane of formula (1): wherein R 1 is the group R 2 C(R 3 ) 2 CH 2 —O—(CH 2 ) m — where R 2 is OH, CH 3 , or CH 2 CH 3 and R 3 is H or CH 2 OH, provided that at least one of R 2 and R 3 contains a hydroxyl (OH) moiety; and m ranges from 0 to 4; R 4 is a C 1 -C 3 alkyl; R 5 is R 1 or a C 1 -C 5 alkyl; and n ranges from 0 to 700.