Study On Preparation Of Graft Acrylic Emulsion Pressure Sensitive Adhesive

With the strong demand for protecting environment, pressure sensitive adhesive(PSA) is updating to emulsion. The conventional emulsion PSA is not satisfying in water resistance, weather resistance, and so on. Hence, scientists are trying new technologies and new mthods to improve emulsion PSA. In this paper, acrylic emulsion PSA was prepared by graft polymerization. Various factors which affect the properties of PSA were studied. The technology and the proportion were optimized, in which the properties of the product have met with the requirement of customers through pilot experiment.Particle sizes and forms of the latexes were observed with TEM. Latex particle of the grafted polymer looked like snowman, while those of the ungrafted polymer and the blended polymer were round. With DSC, Tg of the grafted polymer was different from those of the ungrafted polymer and the blended polymer. So it was proved that the method of polymerization was graft with TEM and DSC .The best dosage of various factors was got by the orthogonal experimental design method and the analysis of various factors. They were as follows: emulsifying agent 1.6%-2.0%, acrylicacid 3%-4%, N-hydroxymethylacrylamide about 1%, 2-hydroxypropyl acrylate about 1%, dodecyl mercaptan 0.1%-0.2%, methyl methacrylate grafted 6%-12%, and initiator 0.4%-0.5%.By variance analysis, initiator and methyl methacrylate grafted had notable effect on tack; methyl methacrylate grafted and N-hydroxymethylacrylamide had notable effect on viscosity; acrylic acid, 2-hydroxypropyl acrylate, dodecyl mercaptan methyl methacrylate grafted and Tg had notable effect on peel adhesion.Vinyl acetate grafted was the best to tack, while methyl methacrylate grafted was the best to holding power by the contrast analysis of grafted monomers.By adding tackifier and plastifier into pressure sensitive adhesive, the author observed that tackifier dosage was 10%-20% which was benefit for the property of PSA, while plastifier was benefit for tack, not for holding power and peel adhesion.