| abstract |
A method of preparing coated pigment particles for dry compounding with a polymeric material such as plastic or rubber, which method comprises the steps of providing particles of a hydrophilic color pigment, mixing the pigment particles with a wax having a given melting point temperature and a brittle condition below a given lower temperature, heating the mixture above a process temperature substantially above the melting temperature and substantially above the boiling point of water to boil away entrapped water, subjecting the mixture to high shear mixing while at the process temperature, cooling the mixture to a temperature below the given lower temperature to produce a solid mass, and, then, breaking the solid mass into flakes. |