3种温热压处理温度和时间对毛竹材表面颜色的影响

The Surface Color of Hot Pressure-Treated Bamboo Material under Three Temperature and Time

选取4~6年生的毛竹竹片,采用高温热压处理,分别在不同的温度(180、210、240℃)和时间(5、10、15、20、30和60 min)工艺条件下,对竹片进行热处理实验,测定靠近竹青一侧与靠近竹黄一侧热处理前后颜色的各项指标。结果表明:随着热处理温度的升高,热处理时间的延长,竹片表面明度L~*降低;明度的最低值为27.76,平均下降了68.12%。颜色在红绿色度轴上向偏红色方向发展,最大值为-119.7,相比处理前平均上升了68.14%;在黄蓝色度轴上最终向偏蓝色方向发展,最接近黄蓝色轴中心的值为6.26,黄度指数b~*在素材基础上平均降低了75.11%。色差ΔE~*逐渐增大,最大达到了263.06。热处理温度对颜色各项指标的影响比热处理时间更为显著,且相比于其他热处理方法而言,高温热压处理法使色差的增长更快速。热处理后,靠近竹黄一侧在各项指标中都比靠近竹青一侧发生了更大的变化,最终靠竹青侧与靠竹黄侧的色差明显减小。

The hot pressure treatment was made on bamboo strips of 4 -6 years old Phyllostachys edulis at three varying temperatures (180,210,240℃ )and for six varying durations (5,10,15,20,30 and 60 min),then various indicators of color close to the inside and outside surfaces of bamboo were measured and analyzed respectively.The results showed that with the increase of heat treatment temperature and duration,the lightness of bamboo strips decreased.The minimum value of lightness was 27.76,with an average decrease of 68.12%. The color of the bamboo strips shifted to red on the red and green axis,with a maximum value of -119.7,an increase of 68.14%on average.On the yellow and blue axis the color of the bamboo strips shifted to blue,the value nearest to the yellow and blue center was 6.26,and the yellow index b decreased by 75.11%on average.The color difference increased,reaching a maximum of 263.06.The effect of treatment temperature on various color indicators was more significant than that of treatment duration.In addition,after heat treatment,there was a greater change in various color indicators of the surface near inner skin than that near the outer skin. Finally,their color difference decreased obviously.