This study of waterborne polyurethane prepolymer blends was done to investigate the effects of different types of soft segments on the dispersion properties and other properties of treated nylon fabrics. The particle size of the dispersion increased, the surface tension of the dispersion decreased, and the contact angle of the nylon fabric with the dispersion decreased when the blending amount of the polydimethylsiloxane polyurethane prepolymer increased. The add-on of ether-type polyurethane increased rapidly when the ether-type polyurethane was blended with a small amount of the polydimethylsiloxane polyurethane prepolymer, whereas the add-on of the ether-type polyurethane reached a maximum at a blending content of 10%. The add-on of the ester-type polyurethane prepolymer constantly decreased with increasing blending amount of the polydimethylsiloxane polyurethane prepolymer. The vertical wicking height of the treated nylon fabrics decreased slightly when the treating agent contained a small amount of the polydimethylsiloxane polyurethane prepolymer. For the treated nylon fabrics with blended prepolymers, the drying time was faster than for the untreated fabric, and the moisture ratio reached about 10% in 15 min (C) 2009 Wiley Periodicals, Inc. J Appl Polym Sci 115: 3550-3558, 2010