Microbeads consisting of a pigmented polymeric material and process for preparing them
AssigneeCiba Specialty Chemicals Corporation
InventorsUlrich Schaedeli, Patrice Bujard
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Abstract
A microbead comprising at least one thermoplastic polymers having distributed one or more compounds which are pigment precursors, the melting temperature of the lowest-melting polymer of the microbead being at least higher than the lowest temperature required to transform all pigment precursors in the microbead into the respective pigments.
Claims5
A process for preparing a pigmented microbead comprising a polymer, an organic pigment of particle size ≦1 μm and optionally one or more further compounds wherein a microbead that comprises a thermoplastic polymer or a mixture of thermoplastic polymers and a pigment precursor or a mixture of pigment precursors throughout distributed therein, the melting temperature of the lowest-melting polymer of the microbead being higher than the lowest temperature required to transform all pigment precursors within the microbeads into the respective pigments is contacted with a Broensted acid in liquid form and wherein the transformation of the pigment precursors to the corresponding in pigments is carried out in presence of said Broensted acid.
Dependencies are inferred from the claim text.