环境友好型人造板用脲醛树脂胶粘剂合成研究

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摩尔比、羟甲基化温度、聚合反应温度、改性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,当甲醛与尿素的摩尔比为1.3:1,羟甲基化反应温度为95～98℃,聚合反应时间30min时,可以合成游离甲醛含量在0.05%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E_0级标准.

The study on friendly-environment urea-formaldehyde resin for wood-based panel

The process of weak alkali-weak acid-weak alkali was used. In the base of the tradition technology of adding urea in one portion to synthesize urea-formaldehyde resin, urea and formaldehyde applied the method of the "added in batches, multi-point section", which was controlled to decrease the free formaldehyde of the ura-formaldehyde resin. In-dividual factor experiments were carried out, which studied the influence of the F/U molar ratio, the first temperature of adding urea, the polymerization reactivity temperature modifier and so on. The optimum condition was obtained: the F/U molar ratio was 1. 3 : 1, controlling adding urea temperature at 95～98℃, polymerization reactivity time for 30 minutes. The free formaldehyde of synthesized urea-formaldehyde resin was less than 0. 05%. Finally, the resin could reach the na-tional E_0 level standard of resin used for wood-based panel.