In-flight encapsulation of particles

Abstract

A method and composition for the in-flight encapsulation of particles such as insecticides, herbicides, molluscicides, acaricides, fungicides, nutrients, pheromones, odorants, fragrances, attractants, repellents, trace elements, plant regulants, and the like is disclosed. The composition comprises, by weight, from 1 to 40 percent of said particles, from 0.1 to 25 percent of a film-forming polymer and from 35 to 99 percent of a liquid which renders said polymers soluble or dispersible. Often, other compounds may be added to impart desirable properties such as other film-forming polymers, crosslinking agent film modifying agents, core agents, and adhesives to improve adhesion to a target. The particle may be in a true solution, suspended, or emulsified through the action of surfactants and/or emulsifying agents. The film-forming polymers include various acrylic polymers and interpolymers of alpha-beta olefinically unsaturated carboxylic acids and N-methylol acrylic amides, as set forth in U.S. Pat. No. 3,007,887. The molecular weight of the polymer generally determines whether the polymer-solvent phase is a solution, a colloidal dispersion, or an emulsion dispersion. Upon ejection from a spray apparatus and during flight through the intervening atmosphere, the solution or dispersion rapidly loses the solvent or carrier liquid component via evaporation, coacervation occurs, and a polymeric membrane forms about the particle. Control of the encapsulated particle size can be achieved through selection of the spray system and of the non-volatiles in the spray at the moment of droplet formation.