Crosslinked vinyl polymer particles and electrographic elements and liquid developers containing such particles

The invention provides new crosslinked vinyl polymer particles, new coating compositions containing such particles, new liquid electrographic developers containing such particles, new electrographic elements containing one or more layers comprising such particles, and new electrographic records containing toner images and/or layers comprising such particles. Each of the inventive particles has an average diameter less than one micrometer and is characterized in that it comprises a crosslinked vinyl addition copolymer obtainable by aqueous emulsion polymerization of a mixture of monomers wherein: 1.5-15 percent by weight of the mixture of monomers comprises polyfunctional vinyl addition-polymerizable monomers in order to form crosslinking structural units in the copolymer; 85-98.5 percent by weight of the mixture of monomers comprises monofunctional vinyl addition-polymerizable monomers selected such that: A. 0-98.5 per cent by weight of the mixture of monomers comprises monofunctional monomers, the homopolymers of which would be insoluble in but swellable by an isoparaffinic hydrocarbon liquid;