amounts of 1 35 suitably 10 25 of a compatible comonomer such as a lower alkyl methacrylate acrylic or methacrylic acid styrene or vinyl toluene may be present in the polymerizable mixture the cross linking agent is present in the polymerizable mixture in an amount from 0 1 to 30 and is a liquid polyunsaturated compound such as a diene or a triene capable of addition polymerization with the unsaturated group of the monomer suitable compounds are low molecular weight liquid polyvinyl compounds such as ethylene dimethacrylate divinyl benzene trimethylol propane trimethacrylate and n n 39 methylene bis acrylamide a commercial form 94 of hydroxyethylmethacrylate hema and hydroxypropyl methacrylate hpma as supplied contains small amounts of methacrylic acid hydroxyalkoxyalkylmethacrylate and dimethacrylates ethylene dimethacrylate in hema and propylene dimethacrylate in hpma hpma is generally a mixture in which the principal monomers comprise 68 75 of 2 hydroxypropyl and 25 32 of 1 methyl 2 hydroxyethylmethacrylate typical compositions in weight percentage follow compound hema 94 hpma 94 ______________________________________hydroxyalkylmethacrylate 86 87higher boiling methacrylate principally hydroxyalkoxy alklymethacrylate 6 5methacrylic acid 3 5 4 5dimethacrylate 1 5 0 7______________________________________ the monomers are diluted in aqueous medium at a level of from 5 to 50 by weight the aqueous medium comprises water and the water soluble polymer the water soluble polymer may be present in an amount as low as 0 05 weight percent amounts above 5 are believed unnecessary and require added time and effort to remove the polymer from the.