Unsatd. polyester resin prodn. by modification with di:isocyanate - before crosslinking to increase thermal and chemical stability

摘要

In the prodn. of unsatd. polyester resins by polycondens. of the 2-naphthol-diene adduct (I) with maleic anhydride (IA) and dicarboxylic acid or their anhydrides with glycol and then copolymerisation with a crosslinking monomer, unsatd. polyester obtd. in known manner is first modified with diisocyanate (II) and then crosslinked. Pref. (II) is an aliphatic diisocyanate of formula OCN-(CH2)n-NCO (with n = 2-10) or aromatic diisocyanate, e.g. 2,4-IDI and its isomers. (II) is added in an amt. of 0.5-5 wt.% w.r.t. the unsatd. polyester. Pref. a soln. of half the amt. of unsatd. polyester in styrene is treated with (II) and then the other half is added. The resin has increased chemical and thermal stability and good industrial properties.