皮革用双组份WPU胶黏剂的制备及性能

Preparation and Properties of Two-component WPU Adhesives for Leather

以异佛尔酮二异氰酸酯、聚己内酯二元醇为原料,二羟甲基丁酸为亲水性单体,三乙胺、1,4-丁二醇、三羟甲基丙烷和有机硅交联剂分别为中和剂、小分子扩链剂、内交联剂和外交联剂,采用丙酮法合成端羟基水性聚氨酯(WPU)乳液。然后加入乳液总质量2%的封闭型水性异氰酸酯类固化剂,制备出不同R值[异氰酸酯指数,n(—NCO)∶n(—OH)]的双组份端羟基WPU胶黏剂。采用FTIR、~1HNMR、激光粒度分析仪、TEM、流变仪对胶黏剂的化学结构,形貌及流变性能进行了表征与测试;通过TGA、多功能材料试验机考察了胶膜的热力学性能和机械性能。结果表明,当R=0.85时,所制备的胶黏剂综合性能最佳,在热失重为5%(D_(0.05))及50%(D_(0.5))时,胶膜热降解温度分别为262.26、349.68℃,胶膜吸水率为19.0%,拉伸强度为14.74 MPa,断裂伸长率为236.53%,剥离强度为421 N/m。

Hydroxyl-terminated waterborne polyurethane （WPU） emulsions were synthesized firstly via acetone method using isophorone diisocyanate and poly （ε-caprolactone） diol as main raw materials, and dihydroxy methyl butyric acid, triethylamine, 1,4-butanediol, trimethylolpropane and organic silicon crosslinker as hydrophilic monomer, neutralizing agent, small molecule chain extender, inner- crosslinking agent and outer-crosslinking agent, respectively. Then, two-component hydroxyl-terminated WPU adhesives with different R values [ isocyanate index, n （-NCO） ： n （ -OH ） ] were prepared by adding 2% （mass fraction, based on the total mass of emulsion ,the same below） enclosed water-based isocyanate curing agents. The chemical structure, morphology and rheological properties of the adhesives were characterized by FTIR, i HNMR, laser particle size analyzer, TEM and rheometer. Furthermore, the thermal and mechanical properties of the films were investigated by thermo-gravimetric analyzer （TGA） and universal tensile testing machine. The results showed that the prepared adhesive exhibited the best comprehensive properties when R value was 0. 85, the D0. 05 and Do. 2 of the film was separately 262. 26 and 349.68 % , and the water absorption, tensile strength, elongation at break and peel strength of the film was 19% ,14.74 MPa,236.53% and 421 N/m,respectively.