The synthesis of silica-sol/acrylate copolymer composite latexes with a gradient concentration in the radial direction and their adhesive properties

Silica-sol/acrylate copolymer composite latexes were prepared by semicontinuous emulsion polymerization. The hard monomer, methyl methacrylate (MMA), was distributed with a gradient concentration in the radial direction, and its effects on polymerization process and adhesive properties were researched. Dynamic light scattering (DLS) was used to monitor the particle diameters and showed that the particles have grown without significant secondary nucleation occurring. The molecular parameters were characterized by gel permeation chromatography (GPC), dynamic mechanical analysis (DMA). Adhesive properties measured were loop tack force, peel strength and shear resistance according to FINAT test methods. The relationship between pressure-sensitive properties and molecular parameters, such as gel content and molecular weight, was evaluated.