Effect of crosslinkers on adhesion properties of electron beam curable polyurethane pressure sensitive adhesive

Polyurethane (PU) based pressure-sensitive adhesive (PSA) using monofunctional urethane acrylate (MFUA) and difunctional urethane acrylate (DFUA) has been cured using electron beam (e-beam) irradiation. The effect of varying e-beam doses on the adhesion properties viz. peel adhesion, shear adhesion and initial tack of PSA has been studied. Effect of various crosslinkers viz. methylene diphenyl di-isocynate (MDI), isophorone di-isocynate (IPDI) and triallyl isocynurate (TAIC) on adhesion properties as well as on moisture vapor transmission rate (MVTR) and gel content of the PSA has also been studied. It was observed that with increasing dose and concentration of crosslinkers all the adhesion properties viz. peel adhesion, shear adhesion strength and initial tack were increased and reached a plateau, and then a decline was observed with further increasing of the dose and crosslinkers concentration. Similarly, MVTR decreased and the gel content increased with increasing dose of electron beam.