| This paper mainly studied a kind of waterborne polyurethane-acrylate(WPUA)composite adhesive for flexible packing application.Firstly one-component acrylic adhesive was used to modify waterborne polyurethane adhesive by cold blending.Secondly WPUA emulsion was prepared by introducing BA/AA/MMA monomers to waterborne polyurethane dispersion(PUD)through seed swelling polymerization or core-shell polymerization techniques.Research results indicated that the particle morphology,Tg and particle size of final WPUA products were greatly affected by the PUD types and polymerization methods.Mechanical properties(T-peerling and Heat Seal strength)of above different emulsions were evaluated on Bopp/VMcpp and PET/PE40 structures.The results showed PUA-3 adhesive owned best performance on coating ability,which composed 75wt%acrylic resin and 25wt%PUD-3.The tensile and heat seal strength performance of PUA-3 adhesive is better than corresponding waterborne acrylic adhesive,waterborne polyurethane or their simple mixture adhesive.TEM found that PUA-3 also had polyurethane core and acrylic shell structure with particle size ranging from 300 to 400nm.Therefore,synergistic effect between acrylic and polyurethane can be achieved by this novel PUA synthesis approach. |
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