热处理条件对杉木颜色变化的影响

以杉木Cunninghamia lanceolata板材为试件,在170,190和210℃分别处理2,3,和4 h,对杉木板材颜色的变化规律进行研究,比较了杉木心边材颜色差异,探讨了杉木热变色的原因。结果表明：杉木心材经热处理后明度L＊和黄蓝色品值b＊均变小,随着温度的升高和时间的延长,L＊和b＊下降幅度逐渐增大,色差ΔE增大;心材明度变化率α和ΔE随热处理条件变化规律与边材分别相似,且两者有很强的相关性,但边材b＊随温度升高是先增后减。温度对杉木颜色变化影响大于时间,在210℃时,时间的影响显著。在相同处理工艺下,热处理条件对边材影响大于心材;杉木心边材存在差异性可能与心边材中木质素含量和抽提物含量有关。表4参18

Heat-treatment influence on Cunninghamia lanceolata discoloration

This paper investigates the effect of heat-treatment temperature and processing time on Chinese fir（Cunninghamia lanceolata） discoloration.Chinese fir boards were heat treated at 170 °C,190 °C and 210 °C for 2 h,3 h and 4 h respectively,and then the color values of Chinese fir before and after heat treatment were determined by a Chroma Meter DC-P3.And the effect on color characteristics of sapwood and heartwood were compared.Results showed that with increases of time and temperature,the brightness of the specimens board brightness（α） decreasesd and the chroma（ΔE） increased.Similar rules of change for brightness and chromatism of sapwood and heartwood were found with a strong relationship between α and ΔE（number of coefficients r =-0.999 5 for both sapwood and heartwood）.Color indexes b＊ of sapwood increased first at 170 ℃,190 ℃ and then decreased at 210 ℃.Overall,temperature had a greater effect on color of Chinese fir boards than time with heat treatment affecting sapwood more than heartwood.Ch,4 tab.18 ref.]