热压工艺对木塑复合板表面性能及稳定性的影响

摘要

采用轧孔工艺处理杉木单板,与高密度聚乙烯(HDPE)薄膜复合制备无醛木塑复合板(WPCP).通过对WPCP表面接触角、2 h及24 h的吸水率和厚度膨胀率进行测试,研究热压工艺(热压温度、热压压力和热压时间)对WPCP表面性能和尺寸稳定性的影响.结果表明,热压工艺对WPCP的接触角和尺寸稳定性均有影响,其中热压温度、热压时间对WPCP的接触角有明显影响,当温度从160 ℃上升到205 ℃时,与素材相比,接触角增大了169％; 热压时间从5 min增加到12 min时,接触角明显提大,增大了146％; 热压压力对WPCP的接触角影响不明显.另外,热压温度、热压压力对尺寸稳定性的影响明显大于热压时间.综合WPCP表面涂饰要求和尺寸稳定性指标,确定优化工艺参数为热压温度175 ℃,热压压力1.2 MPa,热压时间10 min.%Chinese fir veneer was rolled out of the hole,and combined with high density polyethylene(HDPE)film to produce non-formaldehyde wood-plastic composite plywood(WPCP).The effects of hot pressing technology(hot pressing temperature,hot pressing pressure and hot pressing time)on the surface properties and dimensional stability of WPCP by testing the surface contact angle,water absorption,and thickness swelling ratio of 2 h and 24 h.The results showed that hot pressing technology had influence on the contact angle and dimensional stability of WPCP,and the hot pressing temperature and hot pressing time have an obvious effect on the contact angle.When the temperature increased from 160℃ to 205℃,the contact angle increased rate 169％compared to reference sample;when the hot pressing time increased from 5 min to 12 min,the contact angle increased rate 146％;the effect of hot pressing pressure on the contact angle was not obvious.In addition,the impact of hot pressing temperature,hot pressing pressure on the dimensional stability was significantly greater than hot pressing time.Taking surface finishing and the dimensional stability of WPCP into account,the optimized condition was hot pressing temperature of 175℃,hot pressing pressure of 1.2 MPa,hot pressing time of 10 min.