环保型脲醛树脂合成方法的研究

Study on synthesis method of urea-formaldehyde resin with low toxicity environmentally

采用降低甲醛/尿素物质的量比、加入改性剂、改进合成工艺等3种途径优化了脲醛树脂的合成方法。实验结果表明：以甲醛和尿素为单体,添加适量的聚乙烯醇和三聚氰胺改性剂,甲醛和尿素最佳物质的量比为1.5∶1,尿素分3次投料,调节pH值为5.5,反应温度控制在85-90℃左右,反应时间60 min,可制得综合性能较好的低毒耐水脲醛树脂。胶液中的游离甲醛质量分数降至0.026%,固含量〉55%,粘度为120-150 s,剪切强度可达2.02 MPa且耐沸水时间可达122 min。产品质量达到国家规定指标。

Three optimizing measures for preparing urea-formaldehyde resin（UF）,such as decreasing the molar ratio of formaldehyde to urea,adding modified reagent and modifying synthesis methods were presented.The experimental results turned out： adding appropriate PVA or melamine,adjusting the molar ratio of formaldehyde to urea to 1.5∶1,adjusting pH to 5.5 adding urea in three portions,controlling reaction temperature between 85～90 ℃ and maintaining reaction time onto 60 min.the low-toxic,water-resisting urea-formaldehyde resin with good comprehensive performances were obtained.The free-formaldehyde content in product was decreased to 0.026%,its solid content≥ 55%,its viscosity was 120～150 s,its shear strength reached 2.02 MPa and the boiling water resistant time was more than 120 min.The quality of the product followed the criterion regulated by our country.