Citric Acid Modified Kaolin and Its Application in Polyamide Wet Coating

The ink absorption of polyamide-coated polyamide textile products containing kaolin is poor. Citric acid was used to modify kaolin, and the adsorptive performance of rhodamine B was studied. The modified kaolin with the best adsorptive ability was selected. The results showed that kaolin modified with a 2.0 M citric acid solution was strongly adsorptive. During the interaction between citric acid and kaolin, H ⁺ acts on the surface and interlayer of kaolin, and on Al ³⁺ and Si ⁴⁺ in the kaolin. This results in an increase in the specific surface area and a smaller particle size. After using modified kaolin in the polyamide wet coating, the ink-absorption of polyamide-coated polyamide fabrics improved and the resulting pH value met Oeko-Tex Standard 100 requirements for textile use.