Abstract
In order to evaluate the durability of polyurethane waterproof coating (PUW), the outdoor exposure test was conducted for 10 years from 1982, as a part of the Comprehensive Technological Development Project of Ministry of Construction. The test proved that PUW satisfied the standard value of JIS A 6012 after 10 years service and the major deterioration factor was the chalking of topcoat surface. Hence the highly durable topcoats should contribute further long service life of PUW. Here we report an interim result in terms of gloss retention ratio and lightness/color difference of the surface after 17 months exposure on various topcoats, which were applied on top of polyurethane coating.
