Abstract:

Objective Down has the characteristics of lightweight, high fluffiness and low thermal conductivity, resulting in excellent thermal insulation performance, and is widely used in cold-resistant textiles. However, it is eroded by exogenous contaminants, especially after absorbing sweat vapor emitted by the human body, causing the adhered bacteria to proliferate rapidly and develop odor which adversely affect the life quality and health. Research and treatment of down with antibacterial functions will greatly alleviate the bacterial breeding and associated problems of down products, and meet the market demand which is of great significance.
Method In order to reduce the loss of down during down processing for antibacterial performance, antibacterial finishing agents were added in the final rinsing bath. After shocking, soaking, centrifuging and drying, the antibacterial down was obtained. The original and finished down were characterized with scanning electron microscopy (SEM), X-ray energy spectrometry (EDS), and Fourier-transform infrared spectrometry (FT-IR). The antibacterial properties of each sample were tested with the plate colony counting method, and the effect of quick antibacterial processing of down was evaluated simultaneously.
Results In the experiment, the chemical structure of down before and after the antibacterial agent finishing were analyzed by FT-IR (Fig.2). The new characteristic absorption signal peak of the antibacterial down appeared at 1 468 and 1 086 cm^-1, which was attributed the characteristic absorption of C-N⁺ groups in the molecular structure of the cationic quaternary ammonium salt antibacterial agent, indicating the antibacterial agent had been successfully attached to down after finishing. The micromorphologies of the down before and after antibacterial finishing were tested and characterized by SEM (Fig.1). The morphology and fluffiness of the antibacterial down were not affected by the quick processing, and the antibacterial agent was filled in and attached to the grooves and angles of the velvet fiber surface. The antibacterial performance test of down was carried out by the plate colony counting method (Fig.4). No strain appeared in the test surface dishes, and the bacteriostatic rate (BR) reached 100.00%, indicating that the antibacterial down had excellent antibacterial properties against Staphylococcus aureus (S. aureus) and Escherichia coli (E. coli). These results indicate sufficient amount of antibacterial agent were adhered to the down surface, showing a broad spectrum of antibacterial performance, which can efficiently sanitize gram-positive bacteria and negative bacteria (Tab.1). After 3 cycles of washing, the BR values of finished down against S. aureus and E. coli remained at 90.00% and 66.18% (Fig.5), respectively, suggesting high water resistance. The basic performance indicators before and after down antibacterial finishing were compared and analyzed, and the impact of the quick antibacterial processing on the fluffy quality of down was slight, and the cleanness, residual fat rate, oxygen consumption and odor of antibacterial down were not affected significantly (Fig.6, Tab.2).
Conclusion The antibacterial finishing of down and the bath treatment of water washing have the advantage of quick process, and the new technology overcomes the shortcomings of dryness and fluffy, which hinders the applications in infiltration and functional finishing. The finishing process is quick, convenient and easy to operate, reducing the loss of raw lint during the preparation of antibacterial down. The antibacterial agent used in this research is an environmentally friendly functional finishing agent, and the down fiber after the antibacterial agent finishing has excellent antibacterial properties, which does not affect the quality of the down.

Key words: down, washing, antibacterial, short-process flow processing, inhibition rate, fluffiness