低温低pH尿素与甲醛反应工艺的研究

A STUDY ON UREA AND FORMALDEHYDE REACTION TECHNOLOGY UNDER LOW TEMPERATURE AND LOW pH VALUE

本文研究了低温低pH尿素与甲醛反应的新方法。研究表明尿素与甲醛反应有着不同的历程,反应过程明显缩短。树脂具有化学改进的骨架结构,当固化时树脂含有亚甲基比亚甲基醚键多得多,树脂的耐水解性更稳定,释放甲醛较少。同时作者提出了低温低pH下尿素与甲醛反应的生成物作为一种基本树脂,以解决脲醛树脂胶粘剂贮存期不长,在贮存与运输中因气温的变化造成树脂变质的难题。

This paper has reported a new method of reaction between urea and formaldehyde under low temperature and low pH value. Investigations show the different reaction mechanism between urea and formaldehyde. The process of reaction involves a relatively short cycle time. The chemical structure and skeleton of the resin are basically changed. It contains much more methylene functionality than methylene other functionality in the cured resin. The resin exhibits hydrolytic stability and the formaldehyde emission is greatly reduced. Authors suggest that the reaction resultant of urea and formaldehyde under low temperature and low pH value can be considered as a prepolymer (basic resin) to solve the difficult issues, in which the storage life of urea resin adhesive is not long and gelling systems are usually obtained since the ambient temperature variation in storage and shipping.