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脲醛树脂是广泛应用于木材工业中一种重要的胶粘剂。对脲醛树脂的两种合成机理和两种合成工艺进行了探讨,并在大量实验的基础上对两种工艺做了比较,结果表明:工艺路线1(弱碱-弱酸-弱碱)合成的UF树脂中游离甲醛含量明显高于工艺路线2(强酸-弱酸-弱碱中低温)合成的树脂中游离甲醛含量;同时工艺路线1合成的UF树脂中的羟甲基含量高于用工艺路线2合成的UF树脂。
Urea-formaldehyde resins are an important adhesive widely used in the wood industry. Two kinds of synthesis mechanism and two kinds of synthetic processes of urea-formaldehyde resin were discussed. Based on a large number of experiments, the two processes were compared. The results showed that the synthesis of UF (weak base-weak acid-base) The content of free formaldehyde in the resin is obviously higher than the content of free formaldehyde in the resin synthesized in the route 2 (strong acid - weak acid - weak base low temperature); meanwhile, the content of hydroxymethyl in the UF resin synthesized in the route 1 is higher than that in the synthesis with the route 2 UF resin.