ABSTRACT
Abstract-Polyurethane dispersions (PUDs) synthesized using varying amounts of butyl acrylate (BA), from 0 i.e. with only NMP as the solvent to 50 wt%, were used as adhesives for laminates, made from PET and LDPE films. These adhesives were characterized by particle size analysis and contact angle measurements, while the graft efficiency of BA on PU was evaluated by FTIR and solvent extraction techniques. The effect of the ratio of BA to PUD on the contact angle and graft efficiency of acrylic monomer onto PU backbone was studied from the peel strength for plastic laminates. It was observed that with increasing BA content in the PUD, both particle size and graft efficiency decreased. These adhesives exhibited very good peel strength for the PET-LDPE laminates, fair for PET-PET and poor for LDPE-LDPE laminates. A strong relation was found between the graft efficiency of the BA and the adhesive characteristics of the PUD. At 40 wt% of BA in PUD the graft efficiency was the highest, while a high contact angle and low peel strength were observed for all plastics laminates. Therefore, lower graft efficiency is better in comparison to high grafting of BA in hybrid PUDs as an adhesive for plastic laminates.
