the cloisite 30b clay it has been shown that nylon nanocomposite fibers developed using antimicrobial modified clays provide excellent antimicrobial properties the modified clays were prepared using ion exchange methods to replace the cations e g sodium potassium with antimicrobial metal ions such as silver copper and quaternary ammonium in addition nylon nanocomposite fibers based on copper and quaternary ammonium ion modified clays show 100 antimicrobial activity against gram positive staphylococcus aureus and gram negative escherichia coli bacteria at an optimum clay loading of 0 75 by weight this activity is retained up to 50 washes a slow release of active agents is one advantage of these materials further the addition of modified clays is found to enhance the tensile strength 4 11 and tensile modulus 12 20 of the nanocomposite fibers as compared to neat nylon fibers the addition of the quaternary ammonium modified clay has no effect on the color of the resulting filaments the addition of copper and silver modified clay in filaments results in an off white and pale golden yellow color respectively the addition of these modified clays in the filaments can improve the dye uptake of the filaments in subsequent dyeing operations for example polypropylene filaments can be dyed with different classes of disperse dyes in the presence of the clay in one exemplary embodiment polyurethane filaments can be dyed with acid dyes this disclosed process of imparting durable antimicrobial activity through modified clays can be applied to other fiber forming polymers such as polypropylene polyester by melt spinning and acrylic or polyurethane fibers by solution.