两次碱一次回流法合成水溶性酚醛树脂胶粘剂

Preparation of Water-Soluble Phenol-Formaldehyde Resin Adhesive by Two Step Alkaline Catalysis and One Step Reflux Process

采用两次碱一次回流法合成工艺代替一次法和两次碱法制备酚醛树脂胶黏剂,通过对酚醛比、反应时间、反应温度、回流时间等反应条件的考察得出:以n(苯酚):n(甲醛)=1:2的比例,在70℃下反应40 min,80℃下反应20 min后升温回流反应45 min得到具有交联结构的酚醛树脂胶黏剂,产品相对分子质量及黏度适中,拉伸剪切强度可达到5 MPa以上,游离甲醛含量低于0.03%,稳定性较好。

The title process was developed to replace the one step alkaline catalysis and two step alkaline catalysis process. The mole ratio of phenol and formaldehyde, time of reaction, temperature of reaction, time of reflow were examined. The result showed that a phenol -formaldehyde resin having cross -linking structure could be prepared from phenol and formaldehyde（ molar ratio 1 ： 2） in aqueous solution at 70 ℃/40 rain or 80℃/20min followed by one - step 45 min refluxing. Molecular weight and viscosity of products was medium, tensile shear strength was over 5 MPa. The free formaldehyde content in resin was lower than0. 03%, with good stability.