Process for producing mono- or oligodispersed spherical particles from melamine resin

摘要

A process for the preparation of spherical, hard, mono- or oligodisperse particles having a diameter of from 0.1 to 100  mu m, by condensation of partially etherified melamine-formaldehyde precondensates which are infinitely soluble in water to give a clear solution, in an aqueous solution of a water-soluble polymer which carries highly acidic groups and has a K value of from 100 to 160, at pH 3 to 6 and at from 20 to 100 DEG C, and condensing the resultant turbid solution until the precondensate has been consumed, giving a dispersion of the particles. The dispersion is neutralised. The particles can be used in the form of the aqueous dispersion or after isolation from the dispersion. …??The particles are spherical, hard, non-swellable particles which can be used, for example, as sizes for plastics, polishes, flatting (matting) agents, extruders and/or as pigments. …??The process allows the targeted preparation of particles of a prespecified size and particle size distribution.