Colloidal size hydrophobic polymers particulate having discrete particles of an inorganic material dispersed therein
AssigneeThe Dow Chemical Company
InventorJitka Solc nee Hajna
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Abstract
Colloidal size particles of an inorganic solid such as magnetic iron oxide or titanium dioxide are encapsulated in a hydrophobic addition polymer such as a polymer of styrene by a polymerization process wherein a water-immiscible (hydrophobic) monomer is dispersed in an aqueous colloidal dispersion of the inorganic particles and subjected to conditions of emulsion polymerization. The resulting encapsulated particles are usefully employed as catalysts, toners, pigments and diagnostic latexes that have magnetic characteristics.
Claims21
A method for preparing a colloidal size particulate comprising the steps of (1) emulsifying at least one hydrophobic, emulsion polymerizable monomer in an aqueous colloidal dispersion of discrete particles of an inorganic solid, said dispersion being maintained in a reasonably stable state with a chemical dispersant and/or surfactant, and (2) subjecting the resulting emulsion to emulsion polymerization conditions to form a stable, fluid aqueous colloidal dispersion of the particulate wherein essentially every particle of the inorganic solid is coated with the hydrophobic polymer resulting from said polymerization such that substantially all of the inorganic particles are maintained in a discrete spaced apart relationship to each other by the hydrophobic polymer;
- the dispersion further characterized in that when the inorganic solid is magnetic, the dispersion remains stable in any applied magnetic field.
A stable, fluid aqueous colloidal dispersion comprising a continuous aqueous phase and a polymer/inorganic solid disperse phase wherein a substantial portion of the particles of the disperse phase comprise a hydrophobic polymer matrix having dispersed therein the colloidal inorganic solid particles such that substantially all of the inorganic particles are maintained in a discrete spaced apart relationship to each other by the hydrophobic polymer;
- the dispersion further characterized in that when the inorganic solid is magnetic, the dispersion remains stable in any applied magnetic field.
A particulate having colloidal size particles wherein substantially all of said particles comprise a hydrophobic polymer matrix and at least one discrete colloidal particle of an inorganic solid dispersed in said matrix, said inorganic solid being iron oxide, titanium dioxide, calcium carbonate, silica, zinc oxide or clay;
- the particulate further characterized in that when the inorganic solid is iron oxide and the particulate is in an aqueous dispersion, the dispersion is stable in any applied magnetic field.
Dependencies are inferred from the claim text.