低游离甲醛含量酚醛树脂胶粘剂的合成

采用两次加碱一次回流法合成工艺代替一次法和两次碱法制备了酚醛树脂胶粘剂。对产物粘度,游离甲醛含量及固化物拉伸剪切强度测试,研究了酚醛比、催化剂加入量、反应温度、回流时间等对产物性能的影响。结果表明:苯酚与甲醛物质的量比1∶2,催化剂加入量为苯酚质量分数的25%,回流反应45 min可得到具有交联结构的酚醛树脂胶粘剂,产品分子质量及粘度适中,拉伸剪切强度可达到5 MPa以上,游离甲醛质量分数<0.03%,稳定性较好。

Preparation of phenolic adhesive with low free formaldehyde content

The phenolic adhesive was prepared by a two-step adding alkali catalyst and a single reflux replaced of one step or two step adding alkali catalyst method.The mole ratio of phenol to formaldehyde,catalyst dosage,reaction temperature,reflux time on the product performance were investigated by the tests of viscosity,free formaldehyde content and shear strength of the product.The results showed that the phenolic adhesive with cross-linked structure was obtained as the conditions as followed: mole ratio of phen...