Breathability studies of electron beam curable polyurethane pressure sensitive adhesive for bio-medical application

• On increasing e-beam dose from 5 kGy to 60 kGy the MVTR decreased continuously.
• Increasing crosslinker concentration from 2% to10% resulted in decrease of MVTR.
• IPDI has the highest and TAC has the least MVTR in PU-PSA system among the crosslinkers.
• MVTR/peel adhesion/shear adhesion/initial tack: IPDI>MDI>CMDI>PMDI>TAIC>TAC.
• Gel content/Tg/crystallinity: TAC>TAIC>PMDI>CMDI>MDI>IPDI.

Polyurethane (PU) based pressure sensitive adhesive (PSA) commonly used in surgical dressing has been made by electron beam (e-beam) irradiation. In contact with biological substrate like skin, PSAs generally lose their adhesive strength due to very low moisture vapor transmission rate (MVTR). In the present study, effects of varying e-beam dose and different crosslinkers on the MVTR of the PU-PSA have been investigated. A comparative study of effects of different crosslinkers showed that PU-PSA with IPDI has the least while that with TAC has the highest gel content and crystallinity and a reverse trend was observed for the MVTR.