Prepararion For Ultra Violet Dismantlble Adhesion By Photoinitiation

Pressure-sensitive adhesive（PSA）has brought great convenvience for our life and has far-reaching signifiance in industry and express-deliver business.However pressure-sensitive adhensive in temporary bonding obviously can not meet the requirement that it can play a fixed role in bonding at the beginning,meanwhile the force can disappear under a certain irritation.Adhesive with this perfofmance has important applications.In response to this situation,we modified the pressure-sensitive adhesive by adding multi-functional photosensitive resin into PSA,We can get it with a good adhesion before UV irritation,playing a role of fixed components.The foce would disappear when exposed to VU light,so that it is convenient to peel without damaging the components.In this study,we investigated the feasibility of photopolymerization instead of conventional thermal polymerization to prepare pressure-sensitive adhesive.It was found that when the polymerization was carried out at 261 mW·cm^-2（at a wavelength of 365 nm）for 15 min,the performance was similar to that of thermal polymerization.The influence of parameters on the adhesive properties were explored.The optimum formula was determined:85%of BA,10%of AA,5%of HPA.It exhibits excellent property of adhesiveness before UV irradition when select four or more multi-photosensitive functional group resin at a amount of 30 to 40%.The 180°peel strength can reach 24N/25mm.However,when exposed to 20mW·cm^-2,365nm UV light for 20s,the 180°peel strength can be reduced to zero.So it is very convenient to deteach and have no harm to the jointed objects.Further more,the effects on the dismantlble property have been researched,including copolymer composition,category of photosensitive oligomer or monomer,the number of functional groups.The mechamism was disgussed through SEM in the last part of the paper.There are two critical factors of the reasons:one is crosslinked structure leads to the contraction of volume,reducing effective bonding area;the other is that interpenetrating nerwork makes it lose rubber elastic,performing plastic properity.