Metal chromate pigment compositions
AssigneeCiba-Geigy Corporation
InventorBernard G. Ziobrowski
Life of this patent
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Abstract
Metal chromate and particularly lead chromate pigment compositions exhibiting low dusting characteristics and improved heat stability in thermoplastics are described. The pigment compositions consist essentially of a metal chromate-containing pigment and the combination of certain fatty acid salts with normally liquid ester plasticizers. Lead chromate pigment compositions containing the combination of a zinc salt of a fatty acid with benzoate, phthalate, stearate or phosphate plasticizers are particularly preferred and exhibit reduced dusting as well as outstanding advantages in heat stability not realizable with either the fatty acid salt or plasticizer alone or by silica encapsulation of the pigment particles.
Claims9
A metal chromate-containing pigment composition in the form of a fine powder having particles of a size less than about 100 microns, improved heat stability in plastics and reduced tendency to dusting said composition consisting essentially of, by weight, from 50 to 85% of a metal chromate-containing pigment selected from the group consisting of chrome yellow, basic lead chromate, lead sulfo-chromate, molybdate orange and molybdate red;
- from 7.5 to 30% of at least one water-insoluble zinc, aluminum, magnesium or calcium salt of a fatty acid containing at least 12 carbon atoms;
- and from 7.5 to 20% of at least one normally liquid ester plasticizer selected from the group consisting of esters of fatty acids and saturated monohydric alcohols, diesters of dicarboxylic acids and saturated monohydric alcohols, fatty acid esters of polyols, benzoic acid esters of polyols and phosphoric acid esters.
A process for producing a metal chromate-containing composition in the form of a fine powder having particles of a size less than about 100 microns, improved heat stability in plastics and a reduced tendency to dusting, said process comprising intimately blending dry particles of a metal chromate-containing pigment selected from the group consisting of chrome yellow, basic lead chromate, lead sulfo-chromate, molybdate orange and molybdate red with, based on the total weight of the composition, from 7.5 to 30% of at least one water-insoluble zinc, aluminum, magnesium or calcium salt of a fatty acid containing at least 12 carbon atoms;
- and from 7.5 to 20% of at least one normally liquid ester plasticizer selected from the group consisting of esters of fatty acids and saturated monohydric alcohols, diesters of dicarboxylic acids and saturated monohydric alcohols, fatty acid esters of polyols, benzoic acid esters of polyols and phosphoric acid esters.
Dependencies are inferred from the claim text.