US Patent 7785437 Anti-microbial carpet underlay and method of making

A method for making antimicrobial rebonded carpet pad includes mixing zinc pyrithione with a polyol to form an antimicrobial polyol mixture concentrate, blending the antimicrobial polyol mixture concentrate with a binder stream, mixing the binder with foam particles and curing the binder. The percentage of zinc pyrithione mixed with the polyol and the addition ratio of the antimicrobial polyol mixture concentrate with the binder stream are selected to provide an overall concentration of zinc pyrithione in the binder of at least about 7500 ppm. The particles and binder are cured into a block and sliced to form carpet pad.