Effect of tackifier and crosslinkers on electron beam curable polyurethane pressure sensitive adhesive

Polyurethane based pressure sensitive adhesive using monofunctional urethane acrylate and difunctional urethane acrylate has been made using electron beam irradiation. The effect of varying electron beam doses on the adhesion properties viz., peel adhesion, shear adhesion and initial tack has been studied. Effect of tackifier and crosslinkers viz., polymeric methylene diphenyl diisocynate, carbodiimide modified methylene diphenyl diisocynate and triallyl cynurate on adhesion properties as well as on moisture vapor transmission rate and gel content of the polyurethane based pressure sensitive adhesive has also been studied. It was found that with increasing dose, tackifier and crosslinkers concentration, all the adhesion properties viz., peel adhesion, shear adhesion strength and initial tack were increased upto a certain dose, concentration of tackifier and crosslinkers, reached a plateau and then levelled off with further increasing the dose, tackifier and crosslinkers concentration. Similarly, moisture vapor transmission rate was decreased and the gel content increased with increasing dose of electron beam.

► The optimized e-beam dose was 20 kGy.
► Optimized concentration of tackifier was 15% while PMDI, CMDI 6% and TAC 4%.
► CMDI has highest while TAC has lowest adhesion properties.
► Tackifier has highest while TAC has lowest MVTR.
► TAC has highest while tackifier has lowest gel content.