자외선 흡수제와 HALS가 첨가된 외장용 폴리우레탄 바니쉬의 분광 측광학적 특성

Spectrophotometrical Properties of Polyurethane Varnish Containing UV Absorber and HALS ( Hindered Amine Light Stabilizer for Exterior )

UV transmission spectra of pure polyurethane varnish films containing hydroxybe nzophenolic and hydroxyphenylbellzotriazolic UV absorbers and HALS(Hindered Amine Light Stabilizer) was investigated by wet(dry) film thickness of 100(40), 130(55) and 160(70)μm. Also Yellowness Index Difference, Lightness Index Difference and Color Difference of the coated woods of Larix leptolepis were analized by traated level of UV absorber(O, 1, 2 and 3%) and HALS(O, 0.5, 1 and 1.5%), weathered for 160 and 320 hours in QUV Weather-Ometer. There was no significant effects on UV transmission spectra of dried polyurethane varnish films in the range of 300 to 400nm. The thicker films, however, the lower UV transmission became and hydroxybenzophenolie was inferior to hydroxyphenylbenzotriazolic in UV transmission spectra. The lowest Yellowness Index Difference, Lightness Index Difference and Color Difference were shown in the coated woods of Larix leptolepis at the treated level, when based on non-volatile content, of 3% in hydroxybenzophenolic UV absorber and of 1.5% in HALS to polyurethane varnish. Yellow Index Difference, Lightness Index Difference and Color Difference in the coated woods of Larix leptolepis increased with the increase of exposure time in QUV Weather-Ometer, in which the least diffcerence were shown at the treated level of 3% both in hydroxybenzophenolic and hydroxyphenylbenzotriazolic UV absorber.