水性聚氨酯鞋用胶粘剂粘接机理研究(Ⅰ)--界面张力影响

Bonding Mechanism of Waterborne Polyurethane Adhesive(Ⅰ):Interfacial Tension

分别测定了不同液体在鞋材聚氯乙烯(PVC)、聚苯乙烯-丁二烯-苯乙烯(SBS)和粘胶剂水性聚氨酯膜的表面接触角,获得了不同基材的表面能参数(Lifshitz-van der Waals分量γ^(LW)、Lewis酸分量和Lewis碱分量γ^+和γ^-),通过粘附功、铺展系数、FT-IR、T型剥离强度测试研究了水性聚氨酯胶粘剂的铺展润湿性、粘接性和界面张力之间的关系。结果表明,界面张力差异是影响铺展、润湿和粘接的主要因素,极性PVC与聚氨酯界面张力差异小,水性聚氨酯粘胶剂润湿铺展性好,粘接性优良;而非极性SBS与聚氨酯界面张力差异大,水性聚氨酯胶粘接性差;SBS表面经卤化和等离子处理引入了极性基团,表面张力中极性Lewis分量增加,铺展润湿性和粘接性明显改善;提高基材表面极性或增加胶粘剂与基材共价键结合是提高非极性基材粘接效果的有效途径。

By measurements of the contact angle of different liquids on shoe substrate- polyvinyl chloride （PVC）, styrene- butadiene styrene rubber（SBS） and waterborne adhesive-polyurethane membrane（WPU）, the surface free energy parameters of polymers, such as Lifshitz-van der Waals componentγ/Lw and Lewis acid-base component γ/＋ and γ/- （electron-acceptor and electron-donor） were obtained. On this base, the relationship among the wettability, adhesive property and interfacial tension of WPU adhesive to substrate were investigated via evaluation of T-peeling strength, adhesion work, spreading coefficient and FTIR analysis. The results indicated that the wettability, spreading and adhesion force was influenced mostly by the interfacial tension difference between adhesive and substrate. WPU adhesive shows better wettability, spreading and adhesion force for polar PVC substrate, whilst shows low values for non-polar SBS substrate. But SBS treated by halogenation and plasma, the wettability and adhesive property were greatly improved due to the introduction of polar groups. It was found that polar treatment of substrate is an efficient way to improve adhesive strength between adhesive and non-polar substrate.