【摘要】 采用弱碱-弱酸-弱碱工艺,在传统一次加料反应的基础上,尿素与甲醛"分批加入,多点分段"控制反应过程,进行脲醛树脂游离甲醛含量减量化的实验。通过单因素实验,考察F/U物质的量比、羟甲基化温度、缩聚反应pH、改性剂、固化剂等对脲醛树脂胶粘剂游离甲醛含量和性能的影响。结果显示,当甲醛与尿素的物质的量比为1.31∶1,羟甲基化反应温度为95-98℃,聚合反应pH4.8-5.1时,可以合成游离甲醛含量在0.1%以下的脲醛树脂胶粘剂,最终使由脲醛树脂胶粘剂制得人造板的性能技术指标达到E0级标准。更多还原

【Abstract】 The process of the weak alkali-weak acid-weak alkali was used this study.On the basis of the tradition technology of adding urea in one potion to synthesize urea-formaldehyde resin,urea and formaldehyde were added by the method of "added in batches,multi-point section",which was controlled to decrease the free formaldehyde of the ura-formaldehyde resin.Individual factor experiments were carried out,which studied the influence of the F/U molar ratio,the first adding urea temperature,the polymerization reactivity time,modifier and so on.The optimum condition was obtained: the F/U molar ratio 1.31∶1,controlling the first adding urea temperature at 95-98 ℃,polymerization reactivity pH for 4.8-5.1.The free formaldehyde of synthesized urea-formaldehyde resin was less than 0.1%.Finally,the resin could reach the national E0 level standard of resin used for wood-based panel.更多还原