Surface protection of poly(vinyl chloride) by photografting of epoxy–acrylate coatings

Abstract

Abstract UV‐curable epoxy–acrylate coatings were used to protect poly(vinyl chloride) against superficial degradation. With α‐hydroxy–acetophenone photoinitiators, the crosslinking polymerization develops in the ms time scale; 50% degree conversion is reached after irradiation times of 2.5 ms in a nitrogen atmosphere and 17 ms in air. The adhesion of the coating on to the PVC substrate can be greatly improved by inducing a photochemical grafting process. The best results are obtained by incorporating the photoinitiator into the top layer of the PVC sheet. Highly crosslinked epoxy–acrylate coatings are very stable toward UV radiations and chemical agents like organic solvents and strong acids. By their light‐screening effect they provide an excellent protection against photodegradation for light‐sensitive polymeric materials.