三聚氰胺改性脲醛树脂工艺条件对体系游离甲醛含量的影响研究

Influence of Process Conditions of Melamine Modified Urea Formaldehyde Resin on Free Formaldehyde Content in System

本文采用"弱碱-弱酸-弱碱"工艺,以三聚氰胺为改性剂,制备了脲醛树脂胶粘剂,考察了甲醛与尿素摩尔比、出料p H值、三聚氰胺用量、尿素投料次数对UF树脂胶粘剂中游离甲醛含量的影响。结果表明,当U/F摩尔比为1.2、三聚氰胺改性剂用量2.5%、尿素分3批次投料时,合成的UF稳定性最好,UF中游离甲醛的含量为0.14%。

In this paper,the urea-formaldehyde resin adhesive was synthesized by alkali-acid-base process.The effect of molar ratio of formaldehyde to urea,pH,reaction temperature and the amount of melamine on the free formaldehyde content of the adhesive were studied.The experimental results showed that with the increase of n(F)/n(U),the content of formaldehyde increased gradually.When the discharge pH was 7~8,the stability was better and the content of formaldehyde was lower.The modification of melamine could significantly reduce the free formaldehyde of UF resin and improve the stability of synthesis.When the n(F)/n(U)was 1.2,the melamine content was 2.5%,the polycondensation temperature was 90℃,and the urea was added with three times,the synthesized UF resin adhesive process was the most stable and the overall performance was the best.