to 30 butadiene is used optimally the ratio is about 40 styrene to about 60 butadiene the acrylamide monomer preferably is present in an amount of about 1 to 4 of the styrene butadiene content of the latex copolymer and optimally about 2 to 3 the acrylamide material may be used individually or as mixtures thereof e g acrylamide and n methylolacrylamide may be used generally in about equal proportions a preferred commercial source of styrene butadiene latex copolymer is 34 6200 sbr 34 sold by the gaf corporation chattanooga tennessee the urea formaldehyde resins of the binder composition also are commercially available materials for example urea formaldehyde resins such as 34 s 3701 c 34 sold by pacific resins and chemicals inc tacoma washington and 34 pr 913 23 34 sold by borden chemical columbus ohio may be used these resins generally are modified with methylol groups which upon curing form methylene or ether linkages such methylols may include n n 39 dimethylol dihydroxymethylolethylene n n 39 bis methoxymethyl n n 39 dimethylolpropylene 5 5 dimethyl n n 39 dimethylolpropylene n n 39 dimethylolethylene n n 39 dimethylolethylene and the like the resin and latex copolymer components of the binder composition are quite compatible accordingly they are intimately admixed in aqueous solution to form a stable emulsion which does not become gummy or gel even after prolonged storage e g for periods of a week or longer which.