Effect of Film Thickness on Durability of PVC Coated Steel

Abstract

We have studied on the effect of film thickness on durability of PVC mainly unpigmented coated steel. Through experimental works, the following conclusions have been obtained.
We found that the remarkable degradation of polyvinyl chloride is caused on the thin layer film and there is difference between initial and the later stages of degradation. We recognized the occurrence of carbonyl group at the initial stage of degradation and double bond development of crosslinking in PVC at the later stage. Moreover, we found that deterioration of PVC is remarkably minimised by addition of pigments to the coatings. Although the PVC coated steel is characterized by corrosion resistance, the corrosion resistance is poor when film thickness is thin. In order to maintain its high corrosion resistance, 120 μm or more film thickness should be necessary.