Pigment dispersion in resin

Abstract

There is provided a pigment concentrate dispersible in plastics and having a substantially improved characteristic extrusion screen life, comprising a dispersion in a resin carrier of an inorganic pigment of the type having a hydrophilic surface, having on its surface in an effective amount a surfactant of the type characterized by an attached polar terminus, in relation to the surface of the pigment, and an unattached nonpolar terminus, in relation to the carrier resin, or of the type characterized by a high molecular weight surface blocking agent. Such pigments include iron oxide pigments, red iron oxide pigment, yellow iron oxide pigment, black iron oxide pigment, divalent ferrite pigments, zinc ferrite pigment, and magnesium ferrite pigment. Such surfactants include dimethyl polysiloxane, isopropyl triisostearoyl titanate, trimethylol propane, trimethylol ethane, and low molecular weight polyethylene. In a preferred concentrate, pigment loading is about 50%, the pigment comprises red iron oxide, the carrier comprises low density polyethylene, and the surfactant comprises trimethylol propane or trimethylol ethane with a treatment level of 0.5% by weight of pigment.

Dependencies are inferred from the claim text.