RAW MIX POWDER COMPOSITIONS AND METHODS OF MAKING THE SAME

摘要

The present invention provides powder compositions comprising mixtures of ingredients as unassociated discrete particles in a raw mix havi ng an average particle size ranging from 1 to 25 .mu.m. The raw mix comprises randomly shaped primary particles consisting of solids of one or more than one film-forming (co)polymer or resin, and may further comprise particles of one or more than one solid additive chosen from melt flow aids, non-film-forming coloring agents, non-film-forming fillers and mixtures thereof. In addition, the raw mix may comprise at least one of particles of one or more dry flow aid, particles of one or more charge control agent. Further, the invention provides methods for making raw mixes consisting essentially of providing and, if needed, combining the one or more necessary solids, and then milling, preferably jet milling, to the desired average particle size. The raw mix powders may be encapsulated to form particles that are air fluidizab le using conventional electrostatic spray equipment. Accordingly, coating powders, toners and film-forming or molding powders can be intimately mixed in exact amounts without extrusion or spray drying or their limitations.