Abstract
The laminates of polyvinyl chloride to metals have widely been applied to exterior building materials in recent years.
These materials usually must have durability for a long period with out repair, re-painting, etc. Accordingly, the weather-resistance of surface polymer such as polyvinyl chloride may be a very important property.
This paper describes the factors which gave effects on photodegradation of polyvinyl chloride on various base metals.
The results revealed that the effects of ultraviolet ray reflection of various metals on the photodegradation were not so remarkable. However, it was observed under accelerated photodegrading condition by using a weather-meter that the photodegradation was affected by other factors such as electrochemical corrosions of base metals, different thermal conductivities of metals, etc.
As the results of electrochemical corrosions, the metal ions migrated into the polyvinyl chloride layer, which was led to powerful photodegradation by such ions having catalytic activity.
Therefore, it was concluded that the effects of base metals on photodegradation of polyvinyl chloride would be explained by the catalytic action due to electrochemical corrosions rather than ultraviolet reflection ratios of base metals.
