Study On Modified Waterborne Acrylate Pressure-sensitive Adhesive

Waterborne acrylate pressure sensitive adhesive(PSA) has been widely used in various industries because of its good adhesion properties, simple production process, environment-friendly and resource-efficient character etc. However, the molecular structure of pure acrylate PSA is linear which lacks of intramolecular cross-linking, and therefore it has some disadvantages, such as low hardness and intensity, poor high and low temperature resistance, poor water resistance. So the acrylate PSA needs to be modified so as to meet the needs of industrial production.In this paper, an organic silane coupling agent γ- methacryloxypropyl trimethoxy silane(KH570) was used to modify the halloysite nanotube(HNTs) and graphene oxide(GO) firstly, then different contents of modified halloysite nanotubes(mHNTs) or functionalized graphene oxide(FGO) were copolymerized with acrylate by emulsion polymerization to prepare composite PSA. The modified and unmodified HNTs or GO were characterized by FTIR, TGA, CA and XRD and the effect of mHNTs and FGO content on optical clarity, thermal stability, viscoelastic and adhesion properties were studied. In addition, KH570 and polyisocyanate crosslinker(GH) were used to modifie acrylate together, the influences of KH570 content on particle size, surface tension, surface roughness,gel content, thermal stability and adhesion properties of PSA were investigated, the effect of GH amount on the adhesive properties of PSA was also studied.The results of FTIR, TGA, CA, XRD verified that HNTs and GO were successfully modified. It was found that the storage modulus, Tg, thermal stability and high temperature resistance of composite PSA increased with the increasing of mHNTs and FGO contents.Peel strength and tack increased first, then they decreased with the increasing mHNTs content, however, shear strength increased with increasing HNTs content. When the weight fraction of mHNTs is 1.5wt%, the PSA has a good comprehensive performance. Peel strength and tack of the PSA decreased a little, then they decreased sharply with the increasing FGO content, but shear strength increased with increasing content of FGO all the time. When the weight fraction of FGO is 1.5wt%, the hybrid PSA has a good integrative performance.The surface roughness, gel content and high temperature resistance of the PSA films increased significantly with the increasing content of KH570. When the weight fraction of KH570 was less than 0.3wt%, the peel strength and tack of PSA decreased inconspicuous, but the peel strength and tack was significantly reduced after the weight fraction was above 0.3wt%, while the high temperature resistance of PSA increased with the increasing content ofkh570 allthetime.fixedtheweightfractionofkh570in0.3wt%andotherconditionsremainunchanged,externalcrosslinkingagentghwasaddedtofurtherimprovethehightemperatureresistanceofpsa.whentheghcontentwas0.7wt%,hightemperatureresistanceofpsawasimprovedsignificantly.theintegrativeperformanceofthepsawasperfectwhenthecontentsofkh570andghwere0.3wt%and0.7wt%respectively.