低毒脲醛树脂胶的合成及胶液中游离甲醛的测定

Synthesis of Low Toxicity Urea-formaldehyde Resin Adhesive and Determination of Free Formaldehyde in Adhesive

探讨了改性剂对降低游离甲醛含量、改善胶粘剂性能的作用机理,研究了三聚氰胺、聚乙烯醇（PVA）改性脲醛树脂胶粘剂（UF胶）的制备工艺和配方,实验得出：采用弱碱-弱酸-弱碱的工艺,添加适量三聚氰胺和聚乙烯醇,反应最高温度控制在90℃,反应时间2~3 h,n（尿素）∶n（甲醛）=1∶1.4,尿素按7.0∶2.0∶1.0的质量比分3次投料,可制得低毒脲醛树脂胶粘剂。

The action mechanism of modifier to reduce free formaldehyde content and to improve the adhesive properties was discussed.Preparation techniques and recipes of modifying urea-formaldehyde resin adhesives（UF glue） with melamine and polyvinyl alcohol（PVA） were introduced.The results show that when adding appropriate amount of melamine and polyvinyl alcohol,the reaction maximum temperature is controlled at 90 ℃,reaction time is 2~3 h,volume ratio of urea and formaldehyde is 1∶1.4, urea is added in mass ratio 7. 0： 2. 0： 1.0 by 3 times, low toxicity urea - formaldehyde resin adhesive can be obtained by the weak base - weak acid - weak base process.