|
More and more emulsion pressure-sensitive adhesive (PSA) is needed with the improvement of people`s awareness of environmental protection. Compared with the solvent acrylate PSA, acrylate emulsion PSA exhibits many virtues, such as low cost, low luxicity, easy operation, high molecular weight and so on. However, poor water resistance and heat resistance limit its application. In order to enlarge its application, modification is necessary.A kind of internal crosslinked acrylate PSA was prepared by emulsion polymerization using butyl acrylate (BA), 2-ethylhexyl acrylate (2-EHA), methyl methacrylate (MMA) as the main material and N-methylolacrylamide as the internal cross linker. Effects of the ratio of the monomers, the content of the emulsifier, initiator, cross linker, reaction temperature and time on the properties of emulsion and PSA were investigated. The results show that the properties of the emulsion and the PSA were perfect when the reaction temperature was 80℃, the reaction time was 6 h, and the mass fractions of emulsifier, initiator, cross linker, 2-EHA and MMA were 2.5%, 0.6%, 1.5%, 12% and 30%, respectively. The properties of PSA 180°peel strength was 330 N?m-1, the tack was No.10 ball, the holding power was above 72h.Epoxy resin is widely used in paints, adhesives and curing agent for its strong adhesion and water-resistance. However, epoxy resin exhibits some drawbacks because of its structure, so modification is needed. In this paper, the epoxy resin was modified by acrylic acid, the interaction between double bonds and epoxy groups, as well as the reaction between hydroxyl groups and carboxyl groups were carried out, resulted in carboxyl groups and double bonds were introduced to epoxy molecular chain. A kind of PSA was prepared using the epoxy-acrylate emulsions as raw material, which prepared using modified epoxy resin as modifier. The properties of the epoxy-acrylate emulsions were characterized by Fourier Transform Infrared (FTIR), Particle Size Analyzer, Atomic Force Microscope (AFM) and Thermogravimetic Analysis (TGA). The adhesives properties were tested by universal tensile machine, initial tack device and holding power device. Effects of the modified epoxy resin on properties of the emulsion and the PSA were studied. The results showed that the properties of modified epoxy-acrylate PSA had large cohesion, high holding strength and excellent heat-resistant, it could meet the needs of the adhesive tape.
|