COMPARISON BETWEEN THE FILM FORMATION MECHANISMS OF CORE-SHELL AND COALESCENT-ADDED HOMOGENOUS LATEX-PARTICLES

Synthetic latices ore used widely in the point, adhesives, paper and c oating industries. These latices consist of surfactant-stabilised poly mer particles dispersed in on aqueous medium. When applied to a substr ate, water evaporates and a film is finally formed. An important step in the formation of the film is the diffusion of the polymer across th e boundaries of the particles, which imports mechanical strength to th e film. Smell amounts of organic solvents ore often added to the latex as coalescing or film-forming aids in order to promote the diffusion of the polymer. However, because of their toxicity, the use of such so lvents will be prohibited in the near future. A solution to this probl em may be the use of new particles with a core-shell structure. in thi s study we show the effect on polymer diffusion and analyse the mode o f action of film-forming aids in films of the polybutyl methacrylate l atex and we report on the promising results that we obtained with late x particles having a polybutyl methacrylate core and butyl methacrylat e/butyl acrylate copolymer shell.