초록 ▼

Polymeric powders of small particle size and size distribution and of irregular morphology are prepared by a limited coalescence procedure wherein a polymer in an organic solvent is dispersed by high shear agitation in an aqueous phase containing colloidal stabilizer particles having opposite electr

Polymeric powders of small particle size and size distribution and of irregular morphology are prepared by a limited coalescence procedure wherein a polymer in an organic solvent is dispersed by high shear agitation in an aqueous phase containing colloidal stabilizer particles having opposite electrostatic charges. The organic solvent is evaporated and the polymer particles are recovered from the aqueous medium. The particles are of irregular shape and narrow particle size distribution and have superior electrostatic transfer properties when used as electrostatographic dry toners.

대표청구항 ▼

[ What is claimed is:] [1.]1. The method for preparing polymeric powders of irregular particle shape which comprisesforming an organic phase comprising an organic polymer dissolved in a water-immiscible organic solvent,forming an aqueous phase comprising water, solid colloidal stabilizer particles h

[ What is claimed is:] [1.]1. The method for preparing polymeric powders of irregular particle shape which comprisesforming an organic phase comprising an organic polymer dissolved in a water-immiscible organic solvent,forming an aqueous phase comprising water, solid colloidal stabilizer particles having a positive electrostatic charge and solid colloidal stabilizer particles having a negative electrostatic charge,mixing said aqueous phase and said organic phase and homogenizing the resulting mixture by high shear agitation, thereby forming a suspension of small particles of said polymer in the water, said particles having a thin coating of said positively charged and negatively charged stabilizer particles on their surfaces, andseparating the water-immiscible solvent from the polymer to obtain a powder of stabilizer-coated polymer particles, of non-spherical, irregular shape.