Studied On UV Curing Pressure Sensitive Adhesives Based On Polyurethane Acrylates

Polyurethane acrylates (PUA) as a reactive oligomer has widely potential and practial use in many fields, which can be cured by ultraviolet (UV). Their properties can be regulated easily by its raw materials. Conventional pressure sensitive adhesives (PSAs) includes solvent, hot melt and emulsion types. Now a new type PSAs cured by UV light provoke a lot of attention due to its environmental benign properties. In this paper a series of new UV-curing PSAs were prepared, their structure properties were studied.1 Isocyanate (NCO) can rapidly react with polyether macroglycol (OH) in the present of catalyst. First step could be finished in 1h, the HEA end capped reaction is difficult to completely finish within a short time, it needs a back reaction process. The productivity of aim PUA oligomer is about 33～47% and vary with different glycol. PUA oligomer shows Newton fluid behaviour under low shear rates, its viscosity decreases while share rates reach a critical value and show a pseudoplastic fluid behaviour. The photoinitiator 651 has a high property and value ratio as used in the PUA oligomer based PSAs. Mono-functional group dilutes can increase surface adhesion while decrease UV-curing rate. Bi-functional group dilutes are appropriate to PSAs based on PVC substrate and increase curing rate. Tri-functional group dilutes only can be used to accelerate UV-curing rate but weaken surface adhesion due to its large volume shrinkage...