Long-Term Antibacterial and Antimildew Polyacrylate-Based TCS@ZIF-8 Leather Coatings Based on Encapsulation and Slow-Release Effects

In this work, we synthesized an acid-responsive zinc metal-organic framework (ZIF-8) at room temperature by a solvent method, which can not only be used as an antibacterial by releasing zinc ions but also as a carrier for antibacterial material encapsulation. Subsequently, the broad-spectrum antibacterial triclosan (TCS) was encapsulated in ZIF-8 by the impregnation method, and a long-term antibacterial and antimildew material with slow-release effect TCS@ZIF-8 was synthesized successfully. The encapsulation rate and drug loading rate of TCS@ZIF-8 prepared by adjusting the mass ratio of ZIF-8 and TCS were 71.9 and 25.1%, respectively. Further, TCS@ZIF-8 was introduced into polyacrylate (PA) emulsion, and PA/TCS@ZIF-8 nanocomposite emulsion was prepared successfully by the physical blending method. When the pH of the coating surface became slightly acidic due to the metabolic byproducts of microbial growth, ZIF-8 in PA/TCS@ZIF-8 disintegrated to release Zn²⁺ and TCS, which can effectively kill bacteria and mold. When the dosage of TCS was 4.0 wt %, the antibacterial rate of the PA/TCS@ZIF-8 nanocomposite film against <i>Escherichia coli</i> and <i>S. aureus</i> was 100 and 97.3%, respectively. Finally, PA/TCS@ZIF-8 nanocomposite emulsion-coated leather was prepared by the spraying method. Compared with the control group that did not use ZIF-8-encapsulated TCS, PA/TCS@ZIF-8 nanocomposite emulsion-coated leather not only showed better antibacterial and antimildew effects but also showed long-term antibacterial and antimildew performance even after being treated under hot and humid environments of 90% humidity and 40 °C for 30 days. Overall, this study not only provides theoretical guidance into the preparation of long-term antibacterial and antimildew coatings for leather but also has great application prospects in paper, clothing, furniture, and other fields, which has great significance in protecting consumers from the invasion of bacteria and mildew.