关键词: 氮化硼, 聚氨酯, 功能涂层, 取向结构, 导热性能, 凉感织物

Abstract: With the continuous improvement of people's living standards, people's demand for clothing has undergone a more diversified transformation. The diversity of consumption makes the market put forward more requirements for the functionality of fabrics. At present, some consumers are more concerned about the softness, wrinkle resistance, and windproof or waterproof performance of clothing, while others are more concerned about the breathable perspiration, cool, and anti-ultraviolet ability of clothing. With the aggravation of global warming, summer extreme temperatures and duration continue to increase, and more and more people realize the importance of fabric heat dissipation ability. Up to now, most of the methods used to improve the heat dissipation capacity of fabrics are to change the fabric structure, increase the heat dissipation porosity, and obtain functional fabrics by adding cool fibers prepared by thermally conductive materials or constructing thermally conductive coating by the grafting load to increase the surface thermal conductivity. However, the former tends to lose the mechanical properties of the fabric due to the increase of voids and has the defects of high energy consumption, high cost, long process, and low efficiency in the spinning process. Therefore, more and more attention would be paid to improving the thermal conductivity of fabrics by grafting loading.
In order to effectively improve the cooling performance of the fabric, the thermally conductive coating constructed by boron nitride (BN)/polyurethane (PU) was studied to improve the cooling effect of cotton fabrics. Starting from the two-dimensional layered thermally conductive material BN, firstly, functionalized BN (FBN) was prepared with ultrasonic stripping as the thermally conductive filler of the functional coating. Then, the cotton fabric was grafted with a silane coupling agent to obtain the modified cotton fabric with abundant hydrogen bonds and active groups on the surface, which is convenient for the effective adhesion of subsequent coatings. Finally, the aqueous PU (WPU) was used as the polymer substrate supported by the coating, and a certain amount of FBN and WPU was configured into the required functional coating dispersions in a certain proportion. The FBN/WPU functional coating was successfully loaded on the modified cotton fabric by the method of one dipping and one rolling and hot setting. In this paper, the thermal conductivity filler FBN was successfully attached to the fabric surface by the efficient combination of the active groups rich in silane coupling agents and WPU. Compared with the functional thermal conductivity fiber, the research method in this paper greatly reduced the production cost. It was found that when the ratio of silane coupling agent to water to ethanol was 1:1:3 and the FBN mass fraction was 15%, the final thermal conductivity of cool fabrics was increased by 811% compared with cotton fabrics. In addition, the coolness coefficient of the fabric was tested. The coolness coefficient of the fabric finished by functional coatings reached 0.220 J/(cm2·s), which met the national standard of China.
The diversified demand requires the market to make more changes to cope with the future environment. We believe that, with the increasing demand for cool fabrics, how to improve the cooling performance of fabrics and maintain the comfort of the body feeling will attract more and more people's attention. The research results can provide a reference for the design and development of functional fabrics.

Key words: boron nitride, polyurethane, functional coatings, oriented structure, thermal conductivity, cool fabrics