| 摘要 |
PURPOSE:To enable decision of the superiority in the weatherability of coated films in extremely short time without performing a long-time natural exposure test or the like by capturing the radicals generated by irradiating UV rays to said films to a radical trapping agent and measuring the change in the radicals of the radical trapping agent before and after the irradiation of the UV rays. CONSTITUTION:Respective paints to be compared of superiority in weatherability are coated on the outside of a sample pipe for electronic spin resonance (ESR) measurement by dip coating, spray coating or the like and are cured at an ordinary temp. or by heating to form the cured and coated films. UV rays are mainly irradiated from a light source to the respective coated films to generate radicals having a short life from the coated films. The radicals are captured in a radical trapping agent and thereafter the difference in the amt. of the radicals generated from the radical trapping agent mainly before and after the irradiation of the UV rays is measured with the ESR device. The time when mainly the UV rays are irradiated may be the time until a difference arises in the amt. of the radicals generated from the radical trapping agent and in the case of irradiating the UV rays with, for example, one low pressure mercury-arc lamp (15W), the difference in the amt. of the radicals is distinct if the distance between the light source and the coated films is 15cm and the UV rays are irradiated for about 120hr. |
