Antifungal Efficacy of Cotton Fabrics Modified Chemically with Metal Salts

Abstract

Cotton fabrics pre-treated by anhydrous succinic acid were modified chemically with metal ions such as Cu²⁺, Zn²⁺ and Fe²⁺ to give antifungal activities. A pre-treatment by anhydrous succinic acid, associated with an increase in the amount of substituted carboxyl groups, was done to accelerate an increase in the amount of the adsorbed metals. The antifungal efficacy was tested by using Trichophyton mentagrophytes (T. mentagrophytes) IFO 5466 cultivated for 1-7 days. For the samples cultivated for 7 days, the growth inhibitory rate for Cu²⁺, Zn²⁺ and Fe²⁺ finishing cotton fabrics were 67.9-92.9 %, 57.1-87.1% and 35.7-85.6%, respectively. The values were higher than 20.0-50.0% obtained for commercial antimicrobial-deodorant fabrics. The tensile strength of modified fabrics was hardly affected by the amount of anhydrous succinic acid. In spite of the increase in the amount of anhydrous succinic acid, no change of color was recognized on Zn²⁺ finishing cotton fabrics, while a little coloration was found on Cu²⁺ finishing cotton fabrics at a low content of Cu²⁺. Thus, it turns out that Zn²⁺ and Cu²⁺ finishing cotton fabrics developed in this study can be applied to hygienic methods for fabrics. The antifungal efficacy was also tested on the finishing cotton fabrics after laundering and light exposure. The growth inhibitory rate decreased as the number of laundering times increased and the irradiating time, but this tendency was less obvious compared to commercial antimicrobial-deodorant fabrics.