固化剂对低摩尔比脲醛树脂固化特性的影响

为了解决低摩尔比脲醛树脂固化速度慢、胶接制品胶合强度低的问题，该文采用甲酸铵、乙酸铵与过硫酸铵组成复合固化剂，与传统氯化铵固化剂作比较，研究了不同固化体系对5种摩尔比脲醛树脂的固化性能及胶合板的胶接强度与甲醛释放量的影响。结果显示:以甲酸铵或乙酸铵与过硫酸铵混合作为脲醛树脂的固化剂，固化时间和适用期可以调控以满足胶合板生产需要，固化后体系的pH值高于以氯化铵为固化剂时体系的pH值，胶合板甲醛释放量明显低于以氯化铵作为固化剂的甲醛释放量。 

Effects of curing agents on curing characteristics of low molar ratio ureaformaldehyde resin.

To solve the problem of low curing rate and bonding strength of low molar ratio urea-formaldehyde (UF) resins, ammonium formate, ammonium acetate, ammonium persulfate, and their composites were used as new catalysts for UF resin. These new catalysts were compared with traditional ammonium chloride curing agent. The effects of these new catalysts on the curing characteristics of five low molar ratio UF resins, the bonding strength, and the plywood formaldehyde emissions were studied. The results indicated that ammonium formate or ammonium can be mixed with ammonium persulfate as UF resin catalyst. The gel time and pot time of UF resins can be controlled to meet the need of plywood production. The pH value of cured UF resin with new catalyst was higher than that catalyzed by ammonium chloride, and the formaldehyde emission of plywood with new catalyst was lower than that catalyzed by ammonium chloride.