POLYMERIC COLOR CONCENTRATES

摘要

A process for making a polymeric color concentrate for use in coloring thermoplastic materials used in making molded plastic articles or fibers comprising the following steps: (a) adding a thermoplastic polymer, preferably a polyester or a polyamide, to an extruder having vents for the removal of vapors and melting the thermoplastic polymer, adding a pigment dispersion comprising at least one pigment, a polymeric dispersing resin and a non aqueous liquid carrier directly to the melted thermoplastic polymer; (b) blending the pigment dispersion and the thermoplastic polymer in the extruder to form the polymeric color concentrate having a uniform color throughout and removing substantially all of the non-aqueous liquid carrier from the resulting color concentrate via the vents of the extruder; and (c) extruding, cooling and pelletizing the color concentrate; in a preferred embodiment of this invention, the color of the color concentrate is continuously measured and the feed rate of pigment dispersion and thermoplastic polymer is adjusted and small amounts of other pigment dispersions are added to adjust the color to a predetermined color standard.