Patent Document ID: 4157323
Application ID: 05789268
Patent Flag: 1

Claim One:
1. A composition comprising an aqueous suspension of small polymeric microspheres having a size of no more than 2000 A and containing a dispersion of 1 to 50% by weight of finely divided, metal containing particles having a size less than the resultant microspheres embedded within the microspheres and being selected from metals or metal compounds of electron dense metals having an atomic number above 50 or magnetically attractable metals and consisting essentially of the addition polymerizate of a monomer mixture consisting essentially of at least 20% by weight of a first ethylenically unsaturated acrylic monomer substituted with at least one covalent bonding functional group selected from amino, hydroxyl or carboxyl; 40% to 70% by weight of a sparingly water-soluble, compatible, unsaturated, second monomer having hydrophobic characteristics, and 1% to 20% by weight of a water-soluble, polyunsaturated, compatible diene or triene cross-linking agent.