Effects of Foaming Methods on Moisture Transfer and Waterproof Properties of Foam-Finished Nylon Fabrics

Abstract

Water vapor permeabilities and waterproof properties of nylon fabrics obtained by foam-coating processes were studied and the influences of foaming methods on the permeabilities and waterproof properties of the coated fabrics were investigated. For the same weight of coated resin film. the water vapor permeability and water resistance of the foam-coated fabrics were far better than those of conventional nonfoam-coated fabrics. Foam-coated fabrics obtained by the foam-mixer method showed the best water vapor permeability and water resistance. the homomixer foaming method was the second and the stirrer foaming method was the third. In the homomixer foaming method. the water vapor permeability and water resistance of foam-coated fabrics showed the best result when the foaming time was 10min or longer and the rotation speed was 4500rpm (rotation energy, 383J/g solution). In the foam-mixer foaming method, the water vapor permeability and water resistance of the foam-coated fabrics were better than those observed for the homomixer foaming method when the foam blow ratio exceeded 4 and the mixing head speed exceeded 700rpm (rotation energy, 12.6J/g solution). The water vapor permeability and water resistance were found to be dependent upon the size distribution of the foam particles. For both homomixer and foam-mixer methods, small and homogeneous foam particles were obtained at higher foaming speeds, longer foaming times and higher blow ratios. and hence higher water vapor permeability and water resistance could be obtained. These results were confirmed by the SEM observation.