nitrogen sites in the polymer and the degree of quaternization desired generally between about 0 5 and about 1 5 moles of quaternizing agent per nitrogen in the polymer is utilized the resulting vinyl betaine polymer containing monomer units having quaternized nitrogen and carboxylate metal salt moieties is suitable for incorporation into a detergent or dye formulation without further purification specific agents suitable to effect the quaternization of the vinyl pyridine polymer include an alkali metal salt of a halogenated carboxylic acid such as for example a sodium or potassium salt of chloro or bromo acetic acid 3 chloro or 3 bromo propionic acid 4 chloro or 4 bromo butyric acid 2 2 dimethyl 3 chloro propionic acid halomaleic acid e g sodium 2 chloromaleate haloglutaric acid e g sodium 2 chloroglutarate haloadipic acid e g sodium 2 chloroadipate and halopimelic acid e g sodium 2 chloropimelate and the like and mixtures thereof the vinylpyridine monomer in the above polymerization can contain an amount less than 70 wt of a comonomer for certain applications required by the consumer suitable comonomers utilized in the polymerization stage of the process include those referred to above in which case the copolymer is recoverable in the same state of purity and small particle size specific examples of free radical polymerization initiators employed in the process include t butyl peroxy pivalate lupersol 11 t amylperoxy pivalate lupersol.