may be selected from the styrenics e g styrene alpha alkylstyrene where the alkyl group has 1 to 4 carbon atoms and the aromatic group may be substituted or part of a larger ring system other examples of z include acrylate esters derived from aliphatic alcohols or phenols methacrylate esters acrylamides methacrylamides n vinylpyrrolidone or suitably substituted vinylpyrrolidones vinyl esters derived from straight chain and branched acids e g vinyl acetate vinyl ethers e g vinyl methyl ether vinyl nitriles vinyl ketones halogen containing monomers such as vinyl chloride and olefins such as butadiene the polymers of this invention can be prepared using conventional polymerization techniques including but not limited to bulk solution emulsion or suspension polymerization they also can be partially crosslinked examples of anionic addition polymers useful in the invention include the following p 7 xu31066 50 experimental polymer based on styrene butadiene copolymer from dow chemical company the addition polymer employed in the invention may be used in an amount of from about 0 2 to about 26 g m 2 preferably from about 1 to about 16 g m 2 any hydrophilic polymer may be used in the invention for example there may be used gelatin or polymers having the following formula r 6 represents.