Polymer gels and method of making same

Claim 1

A solid composition having a predetermined configuration varying from shaped three-dimensional masses to discrete finely-divided particles and exuding a non-volatile, non-drying oil when pressure is applied thereto, said composition consisting essentially of (a) about 20-65 percent by weight of a polymer of an acrylate monomer with up to a minor amount of a cross-linking agent for said monomer and sufficient to give a solid water-insoluble polymer, and (b) from about 35 percent to about 80 percent by weight of a non-volatile, non-drying oil which is a solvent for said acrylate monomer and such cross-linking agent and at least a partial swelling or plasticizing agent but non-solvent for said solid polymer, said solid composition being constituted of a solid coherent lattice structure of said polymer molecules polymerized in said predetermined configuration with said oil occludeD in situ uniformly throughout said lattice and having its external surfaces free of visible oil except when subjected to pressure, said oil being sufficiently compatible with said polymer that it is occluded in substantial entirety within said polymer lattice structure, said monomer being oil-soluble and selected from the group consisting of acrylic acid, methacrylic acid, and the alkyl, cycloalkyl and hydro-alkyl esters thereof and said cross-linking agent having at least two terminal ethylenically unsaturated groups, and selected from the group consisting of allylmethacrylate and divinylbenzene, and said oil being selected from the group consisting of monohydric alcohol esters of carboxylic acids, monohydric alcohol esters of phosphoric acid, aliphatic hydrocarbons, aromatic hydrocarbons, and chlorinated aromatic hydrocarbons.