| 摘要 |
<p>This invention relates to improved vinyl acetate-ethylene emulsions for use in formulating high performance paints without the need for coalescing solvents. These latexes are based on copolymers of vinyl acetate and ethylene optionally containing a comonomer such as an alkyl acrylate or methacrylate. Paints formulated from these latexes, without coalescing solvents, are characterized as having substantially no insolubles, the resin particles in the emulsion are characterized as having a particle size of from 0.2 to 0.35 microns measured as weight average by capillary hydrodynamic fractionation. In other words, the copolymer particles are characterized in that a small percentage, up to about 5% of the total number of particles in the latex, have an average size greater than 0.35 microns, and a small percentage have a size smaller than about 0.2 microns. Further the resin particles are essentially monodisperse. Ethylene in place of the conventional acrylate as the low Tg monomer wit the resulting resin particles having a Tg of from minus -5 to 8 DEG C. The improved process for producing the emulsion or latex includes as an important component the formation of a seed latex and then polymerizing the monomers in the presence of the seed, the monomers being introduced over a period of time.</p> |
