| Pressure sensitive adhesive (PSA) for biological surface is of good tack, strong bond, and no allergy on human skin, which is one of the important development directions in the field of health, cosmetic and personal care adhesion. In this paper a acrylate emulsion PSA was prepared with acrylic as the main monomer, and grafting polyethylene glycol (PEG) molecule on the main chain of acrylic polymer. And The PSA appearance is a milky white, translucent and blue light state, and it is of no smell, good viscosity, good mechanical properties, vapor permeability, moisture absorption, drug compatibility and good self film formation performance. So it is suitable for the biological surface.The acrylic emulsion PSA's preparation method, optimal agent ingredients and performance properties were studied systemly. The core-shell emulsion polymerization of monomer pre-emulsion method was chosen as the preparation process for PSA with good self film formation. The PSA's main components were butyl acrylate (BA), butyl methacrylate (BMA) and acrylic (AA), which reacted for 1.5~2h with the stirring rate of 200rpm at 82℃, and then were kept insulated for 1h; Stepped rising temperature with the 3℃gradient, which made the polymerization conversion rate more than 95%. At the end of reaction, the synthetic polymer was added with PEG-2000 and cooled, then an excellent performance PSA with low-cost was got. Some factors affected PSA properties were investigated according to orthogonal experiments plan, and the optimal agent ingredients and the proper preparation conditions were selected by the operational condition experiments. The reaction conversion rate was the top value 98% for the initiator content was 0.81~1% and the reaction temperature over 82℃. The optimal PSA properties was gained when the core monomers ratio BA/BMA was 11/9, the shell monomers ratio BA/BMA/AA was 34/15/5, the emulsifier content 4.05~5%, the initiator 0.81~1%, AA 6.4~6.8%, PEG-2000 20~24%, the monomer/water ratio 90/70, and the reaction temperature 82℃. At this operation condition point, the PSA latex viscosity is 100~130mPa·s, the tack 13~16#, holding power over 24h, peel strength 23.83~39.02N/20mm, and tensile strength 0.889~1.2MPa. Furthermore, the PSA film was of good transparency, the vapor rate permeating across the film was 524.01~947.52g/m2·24h, and the moisture absorption content in PSA film was 62.7~75.7%.The FTIR results show that, PEG molecules but null acrylic monomers were distributed in the water phase of PSA freely, so the prepared PSA odor was not unpleasant. The DSC and TEM results indicated the existence of core-shell structure in PSA latex and two glass transition temperatures which were -40℃and -10℃. The diameter of PSA emulsion particles was about 80~120nm.In addition, the PSA could be used derectly without any backing since its super tensile strength and good self-film-formation. And its proper drug compatibility and inexpensive cost were found.
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