Easily dispersible formulations of pigments and their use in tinting base media
Formulations of easily dispersible (ED) pigments comprising a combination of a carboxylic acid polymer and a non-ionic alkoxylated surfactant are disclosed. The combination is used in the formulation of a plurality of pigments. The formulations are suitable for mixing with a base medium at the point-of-sale (PoS) or by the end user.
1. A spray dried particulate formulation consisting essentially of a plurality of pigments and 0.5 to 3.6% (w/w) hydroxylated amine, 0.56 to 4.52% (w/w) acrylic acid polymer and 4.5 to 37.7% (w/w) ethylene oxide-propylene oxide diblock copolymer.
2. The formulation of claim 1 consisting essentially of a plurality of pigments and 0.5 to 2.3% (w/w) hydroxylated amine, 0.8 to 2.8% (w/w) acrylic acid polymer and 7.5 to 19% (w/w) ethylene oxide-propylene oxide diblock copolymer.
3. The formulation of claim 2 where the particles are of a hollow doughnut morphology.
4. The formulation of claim 3 where the formulation has a bulk density in the range 0.7 to 1.1 g/mL.
5. The formulation of claim 4 where the particles have a median diameter in the range 20 to 200 μm and a particle size distribution of less than 1.25.
6. The formulation of claim 5 where the particles have a median diameter in the range 30 to 120 μm and a particle size distribution of less than 1.25.
7. The formulation of claim 6 where the particles have a median diameter in the range 50 to 100 μm and a particle size distribution of less than 1.25.
8. The formulation of claim 1 where the hydroxylated amine is 2-amino-2-methyl-1-propanol.