多重改性水性聚氨酯胶粘剂对聚烯烃薄膜的粘接机理

以自制的多重改性水性聚氨酯(WPU)复合乳液为基料,配合适量的消泡剂、润湿剂和偶联剂等,制备出软包装覆膜用多重改性WPU胶粘剂。考察了消泡剂、润湿剂和偶联剂用量对胶粘剂性能的影响,分析了胶粘剂对聚烯烃薄膜的粘接机理。结果表明:该胶粘剂对经过电晕处理的聚烯烃薄膜表面润湿性好、润湿速率快,并且和基材表面存在着广泛的氢键,因此其与聚烯烃薄膜表面有较强的吸附作用;通过外加偶联剂己二酰肼(ADH),强化了胶粘剂对聚烯烃表面的粘接效果;当w(消泡剂)=0.3%、w(润湿剂)=0.5%和w(ADH)=0.5%时,BOPP(双向拉伸聚丙烯)膜和CPP(流延聚丙烯)膜之间的最终粘接强度为264 N/m,可以满足软包装覆膜用胶粘剂的使用要求。

Adhesion mechanism of multi-modified waterborne polyurethane adhesive for polyolefin films

A multi-modified waterborne polyurethane(WPU) adhesive for flexible packaging laminated films was prepared when a self-made multi-modified WPU composite emulsion was used as matrix,and some additives(such as antifoam,wetting agent and coupler) were introduced into systems.The influences of antifoam,wetting agent and coupler contents were investigated on performances of adhesive.The adhesion mechanism between adhesive and polyolefin films was analysed.The results showed that the sorption between adhesive and polyolefin film surface was stronger because the adhesive had well wetting ability,fast wetting speed and extensive hydrogen bonding on polyolefin film surface treated by corona discharge.The bonding effect between adhesive and polyolefin film surface was intensified when adipic dihydrazide(ADH) coupler was introduced into systems.The adhesive could meet application requirements of flexible packaging laminated films because the final bonding strength between BOPP film and CPP film was 264 N/m when mass fractions of antifoam,wetting agent and ADH were 0.3%,0.5% and 0.5%,respectively.