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研究了以4,4’-二苯基甲烷二异氰酸酯和异氟尔酮二异氰酸酯、聚碳酸酯二元醇和羟甲基酸类扩链剂为原料,合成了阴离子聚碳酸酯型水性聚氨酯,在此基础上用有机硅对其进行改性,探究有机硅改性对于水性聚氨酯性能的改善。结果表明:水性聚氨酯较适宜的合成工艺条件为初始n(—NCO):n(—OH)(R)=3.5,三羟甲基丙烷的质量分数为3%,2,2-二羟甲基丁酸占总质量的6%,羟基硅油的质量分数为1%,预聚反应时间在3.5h左右,预聚温度控制在75℃,扩链温度降低到55℃为宜;有机硅改性后聚氨酯材料的拉伸强度增大,断裂伸长率下降,成膜塑感加强;有机硅的加入在很大程度上提高了聚氨酯膜的耐水性。
In this paper, anionic polycarbonate type aqueous polyurethane was synthesized by using 4,4’-diphenylmethane diisocyanate, isophorone diisocyanate, polycarbonate diol and methylol chain extender as raw materials. Based on this, it was modified with silicone to explore the improvement of the performance of water-based polyurethane by silicone modification. The results showed that the suitable synthesis conditions of aqueous polyurethane were as follows: initial n (-NCO): n (-OH) (R) = 3.5, trimethylolpropane content 3%, 2,2- Butyric acid accounted for 6% of the total mass, hydroxy silicone oil mass fraction of 1%, prepolymerization reaction time of 3.5h, prepolymerization temperature control at 75 ℃, chain extension temperature is reduced to 55 ℃ appropriate; silicone modified The tensile strength of polyurethane material increases, the elongation at break decreases, and the plasticity of film increases. The addition of silicone greatly improves the water resistance of polyurethane film.