Mono-size Polyisocynate nanoparticles as the interfacial crosslinker of WPU/Acrylic core-shell latexes to adhesively bond laminates

Uniform waterborne polyisocyanate nanoparticles were synthesized and used to interfacially crosslink the colloidal core-shell Polyurethane/Acrylic hybrid latexes (WPU/AC) to enhance the adhesive film strength of hybrid system. To fulfill this target, blocked waterborne polyisocyanate (BPIC) were synthesized out of Toluene diisocyanate (TDI), Dimethylpropionic acid (DMPA) and Methyl ethyl ketoxime (MEKO) as blocking agent. It was characterized by Dynamic light scattering (DLS), Fourier-transform infrared spectroscopy (FTIR) and Thermogravimetric analysis (TGA). By titration the free isocyanate groups content of BPIC, blockage efficiency was estimated 8.4%. Adhesion strength of 1.5 MPa and 4% elongation at break represented the polyisocyanate crosslinked WPU/AC film suitable for Wood/PVC joint implying comparable performance with similar commercial European products.