mercaptoethanol sodium hypophosphite dodecyl mercaptan and thioglycolic acid the chain transfer agent will generally be present in an amount of about 0 1 to 10 percent by weight of the total emulsion though more or less may be used any conventional sequestrant may also be present in the aqueous phase such as ethylenediaminetetraacetic acid or pentasodium diethylenetriamine pentaacetate or aminomethylene phosphonic acids the sequestrant is generally present in an amount of about 0 01 to 2 percent by weight of the total emulsion though more may be used following preparation of the preliminary emulsion polymerization of the monomers is commenced at a temperature sufficiently high to break down the initiators to produce the desired free radicals generally a suitable temperature is about 20 u00b0 c to about 200 u00b0 c with a preferred temperature of about 0 u00b0 c to 100 u00b0 c the polymerization is generally run at a ph of about 2 to about 12 preferably about 3 5 to 5 5 and most preferably about 4 0 to 5 0 and a suitable amount of base or acid or water soluble buffer solution may be added to the preliminary emulsion to achieve the desired ph a succinic acid borax buffer maintains a ph of 3 6 to 5 8 depending on the ratio a sodium acetate acetic acid buffer maintains a ph of 4 2 to 4 6 depending upon the ratio the polymerization is usually completed in from about an hour or two to several days depending upon the monomers employed and other reaction variables it is generally carried out at atmospheric pressure but higher pressures are advantageously.