改性异氰酸酯树脂胶玉米秸秆皮板工艺

摘要

以异氰酸酯(PMDI)改性的脲醛胶作为胶黏剂,采用正交试验法分析了热压时间、成板密度、施胶量、胶混合比对玉米秸秆皮板主要物理性能的影响.结果表明:热压时间对玉米秸秆皮板的24h吸水厚度膨胀率(24h TS)、弹性模量(MOE),成板密度和改性脲醛胶/异氰酸酯(UF/PMDI)的混合比例对24hTS、IB、MOE以及施胶量对24hTS均有高度显著性影响.在一定范围内,秸秆皮板材的物理力学性能指标随着热压时间、密度以及施胶量的增加而增大,异氰酸酯施加量的增加能持续提高板的性能.当工艺条件为:热压时间4～5 min,板密度0.9g/cm3,施胶量12％,胶量比(UF/PMDI)7∶3时制得的板材性能最佳.%Influences of hot-pressing time, density of composite, resin content and mixing ratio of UF resin to isocyanate on the properties of corn stalk skin composite with UF resin modified with PMDI were studied through the orthogonal experimental method. Results show that hot-pressing time has significant effects on 24 h thickness swelling rate and modulus of elasticity; composite density and mixing ratio of UF to PMDI have significant effects on 24 h thickness swelling rate, internal bond strength and modulus of elasticity; resin content has a highly significant effect on 24 h thickness swelling rate. Physical and mechanical properties of the composite, to a certain extent, increased with increasing hot-pressing time, density and resin content. The increasing amount of isocyanate could continually improve the properties of the composite. The optimal technology process conditions were obtained as hot-pressing time 4-5 min, composite density 0.9 g/cm3, resin content 12% , and mixing ratio of UF to PMDI 7 : 3.