改性低甲醛释放脲醛树脂的固化特性与合成工艺研究

摘要

实验采用不同种类助剂合成了改性低甲醛释放脲醛树脂,并主要针对其固化特性进行了研究,结果发现:添加助剂1+2+3的脲醛树脂呈现出最快的固化速率,比空白样品提高了约15％,但是力学性能较差.因此在添加助剂1+2+3的基础上又对合成工艺进行了优化,结果表明:1)三聚氰胺能有效降低脲醛树脂的甲醛释放量,添加3％wt后甲醛释放量仅为0.28 mg/L;2)增加树脂黏度能有效提高胶黏剂的胶合强度,二次缩聚黏度上升到25 s后,湿强度达0.74 MPa,达到了国家胶合板Ⅱ类板标准,优化效果良好.%The modified urea-formaldehvde resin with low formaldehyde release was synthesized with different kinds of additives in this paper.And the curing characteristics were studied mostly.The results indicate that:the ureaformaldehyde resin with additive 1+2+3 shows the fastest cure rate,which improves about 15％ compared with the blank sample,but the mechanical property is poor.So the synthesis process is optimized based on the addition of additive 1+2+3,the results show that:1) melamine has a very significant effect on reducing free formaldehyde,when the added amount reaches 3％,the formaldehyde release is only 0.28 mg/L;2) increases the viscosity of the resin can improve the bonding strength of the adhesive obviously,the wet strength reaches 0.74 MPa when the secondary polycondensation viscosity rises to 25 s,which can achieve the national plywood class Ⅱ standard,and can has a good optimization effect.