新型脲醛树脂胶黏剂的改性

Special modification of urea-formaldehyde adhesive

研究了一种新型改性剂对于脲醛树脂胶黏剂的改性效果,并与传统改性方法进行了比较。改性剂采用特制的羟基丙烯酸酯树脂(乳液)及端异氰酸酯基水性聚氨酯树脂。研究发现,传统改性方法中,随尿素与甲醛的物质的量比的增大,脲醛树脂中游离甲醛含量减小,但其黏合强度降低;使用这种新型改性剂既可降低游离甲醛含量,又能明显提高黏合强度及耐水性,且改性效果随改性剂用量的增加而增加。其中,聚氨酯树脂对脲醛树脂黏合强度的改进最为明显,但对耐水性的改性效果稍差;而高羟基含量的丙烯酸酯树脂比低羟基含量的改性效果好。

New unique modifiers of self-made hydroxyl acrylic resin （emulsion） and isocyanatoterminal waterborne polyurethane were developed. The modification effect of the new modifiers to urea-formaldehyde resin was studied and compared with traditional modification method. The research showed that while the molar ratio of urea/formaldehyde was increased in the traditional modification method, the content of free formaldehyde was decreased, but the adhesion strength was reduced. However, the content of free formaldehyde was decreased while adhesion strength and water resistance were increased obviously when the new modifiers were used. The higher the content of the modifiers, the stronger the modification effect. The waterborne polyurethane showed better improvement of the adhesion strength of UF resin, but not so good to water resistance. The modified effect of the high hydroxyl content acrylic resin was stronger than the low hydroxyl content acrylic resin.