环保型脲醛树脂合成方法的研究

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。

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

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.