Agent for pre-treatment of rough mineral materials for pigmentary applications
AssigneeCoatex
InventorsGeorges Ravet, Catherine Bonnet, Jacques Mongoin
Life of this patent
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Abstract
A pre-treatment of rough pigmentary mineral materials to eliminate the viscosifying effect of the swelling clays present in said materials used to condition said materials before refining them in an aqueous medium by abrasion or grinding. The method enables the production of refined pigmentary suspensions with a concentration of at least 75% by weight and low viscosity and stable over time. The pre-treatment agent is comprised of acid polymers and/or copolymers containing at least one carboxylate ethylenic monomer. Suspensions with high concentration of pigmentary mineral materials are prepared from the conditioned materials.
Claims15
A method of pre-treating a rough pigmentary mineral material containing a swelling clay, comprising the steps of:
- (i) obtaining a rough pigmentary mineral material containing a swelling clay;
- and
- (ii) contacting said rough mineral material prior to grinding with a pre-treating agent comprising at least one carboxylate ethylenic acid containing polymer or copolymer, in an amount sufficient to provide a pigmentary mineral material suspension after grinding which comprises at least 75% by weight of said mineral material wherein said contacting step comprises:
- (a) impregnating substantially dry rough pigmentary mineral material with said pre-treating agent with agitation,
- (b) adding water to said impregnated mineral material up to an amount at most equal to 25% by weight with regard to said impregnated mineral material,
- (c) mixing said water containing impregnated mineral material to produce a viscous plaste state or a granular particle state,
- (d) treating said viscous paste or said granular particles with an aqueous solution of an alkali or alkaline earth hydroxide to obtain a pH of about 9 to form a fluid aqueous suspension, and
- (e) colleting said fluid aqueous suspension.
Dependencies are inferred from the claim text.