Weatherability of Polypropylene by Accelerated Weathering Tests and Outdoor Exposure Tests in Japan

As a joint study of the Polymer Subcommittee in the Industrial Technology Cooperative Promotion Committee, in which members are Japanese local governmental research institutes and National Institute of Advanced Industrial Science and Technology (AIST, Japan), carried out from 2010 to 2012, polyethylene reference sample (PE-RS) pieces and six types of polypropylene (PP) were subjected to accelerated weathering tests and outdoor exposure tests, resulting in the following findings. (1) The PE-RS was subjected to eight 100 h exposure tests in the same test machine. The accelerated weathering test machines of the participating institutes had high reproducibility. (2) The PE-RS CI values were greater when the temperature in the chamber was greater during accelerated weathering tests, and there was a high correlation with the average temperature in the outdoor exposure tests at 20 places in Japan. (3) By comparing the change in PP strength by normalizing the degradation environment using the PE-RS CI values, the accelerated weathering test with results showing the highest correlation with the outdoor exposure test results was the one with the xenon arc lamp at an irradiance of 60 W/m2 and a BPT of 63°C.