Dark storage stable UV-curable polyester resins - contg hydroxycarboxylic acid and retaining relatively fast cure quality

摘要

The dark storage stability of unsatd. polyester resins, which are cured by UV radiation, and their prepnd are improved by adding malic, lactic, tartronic, tartaric and/or citric acid as stabilisers. The dark storage stability is satisfactory for practical purposes, at =50 degrees C while UV exposure still causes relatively fast cure. The amt of stabiliser (citric acid) used is 0.3-2 (0.3-1.2) wt.% w.r.t. the wt of the curable binder, and photoinitiators are also added.