- 期刊
熱處理對三種國產人工林木材物理性質之影響（III）－顏色變化
Effects of Heat Treatment on the Physical Properties of Three Domestic Plantation Wood Species (Ⅲ)- Color Changes
摘要
本研究以CIE-L*a*b*顏色參數探討杉木（Cunninghamia lanceolata）、柳杉（Cryptomeria japonica）及大葉桃花心木（Swietenia macrophylla）三種人工林木材經170℃、190℃、210℃及230℃四種溫度與分別維持1、2、4及8h的熱處理後之木材及其經1152 h之人工耐候試驗後之顏色變化。結果顯示，經熱處理後之表面顏色隨處理溫度上升與時間增長而變深，熱處理造成木材顏色變化主要發生在前1h內，隨後之變化輕微，其中大葉桃花心木熱處理材與未處理材之色差值（ΔE*）最大，杉木次之，柳杉相對的顏色變化較小。三種未處理木材在人工耐候試驗初期即產生顯著的顏色變化，但經1152 h曝露後，三種木材ΔE*值差異非常小，三種木材中以柳杉未處理材之抗光劣化性能較佳。在人工耐候試驗下，210℃以上溫度熱處理杉木與大葉桃花心木試材可有效改善其表面顏色耐光性；但柳杉熱處理材與未處理材間之ΔE*值差異不明顯。
並列摘要
The main objective of this study is to investigate the color changes of three domestic plantation wood species including China fir (Cunninghamia lanceolata), Japanese cedar (Cryptomeria japonica) and big-leaf mahogany (Swietenia macrophylla) after heat treatment and during artificial weathering by using CIE-L*a*b* color parameters. Heat treatments were carried out at temperature levels of 170℃, 190℃, 210℃ and 230℃ for time spans of 1 h, 2 h, 4 h and 8 h. The experimental results showed that a darkening of color occurred, the higher the temperature and the longer the time span of heat treatment, and the greater the color changes of the heat treated wood. During the first 1 h of heat treatment the total color change (ΔE*) increased rapidly. After this period, the ΔE* change was moderate. The big-leaf mahogany after heat treatment showed the highest color change, followed by China fir, and the color of heat-treated Japanese cedar was relatively stable compared with the original wood color. The color of control wood samples changed significantly during the initial stage of artificial weathering, while the differences of ΔE* values among three wood species after 1152 h exposure were very limited. The results of color changes indicate that China fir and big-leaf mahogany heat treated over 210℃ were effective in restricting artificial weathering induced color changes. However the differences of ΔE* values between control and heat treated Japanese cedar were not significant.