Abstract:

Objective Inflatable clothing is a type of warm keeping clothing that replaces down with air because the thermal conductivity of stationary air is the smallest, and inflatable clothing is constantly developed and designed using this principle. However, there is currently less research on inflatable fabrics, and it is necessary to explore the relationship between the thickness of the air gap inside the fabric and the thermal resistance. Therefore, the purpose of this study is to grasp the relationship among inflation volume, the thickness of air layer and the thermal resistance, and to establish relevant models to provide theoretical reference and application value for enterprises and researchers.

Method This research selected 12 different types of commercial inflatable fabrics, and evaluated the thermal resistance of these inflation fabrics with 5 different inflation volumes of 0%, 30%, 50%, 70% and 100%. Statistics analysis of experimental results was performed through single-factor analysis, correlation analysis, fitting regression analysis and other methods to understand the relationship among the three.

Results The experimental results show that the greater the inflation volumes, the greater the thickness of the air gap, and the more linear distribution of the two. The regression equation was obtained (Fig. 5). When the inflation volume was small, the difference in the air gap thickness between the fabrics was small, and the greater the inflation volume led to the more significant difference in the air gap thickness, and this was true for different fabrics (Fig. 3). The thermal resistance of the aerated fabric increased with the increase of the inflation volume (Fig. 4), and the thermal resistance was affected by the performance of the fabric itself. There were significant differences in different inflation states. As an example to illustrate, fabric 10^# was thicker and the thermal resistance was larger. Overall, the thermal resistance of the aerated fabric rose and then stabilized with the increase of the inflation volumes, and a Logistic model was established between the two. When the inflation volume was within 50%, the thermal resistance changes were more significant, the thermal insulation effect was significant, and with the continuous increase of the inflation volume, the thermal resistance value gradually stabilized (Fig. 6). Logistic model was established between the air gap thickness and the thermal resistance, and the inflation thermal resistance increased with the increase of the inflation volumes, showing a trend of first significantly increasing and then becoming stable (Fig. 7). When the air gap thickness was about 20 mm, the thermal insulation performance reached the best.

Conclusion By thickness and thermal resistance tests, this paper explores the relationship between different inflation volumes, air gap thicknesses and thermal resistance, establishes a relationship model, and draws the following conclusions. The greater the inflation volume, the greater the air gap thickness, and the more linear distribution of the two. The relationship between thermal resistance, inflation volume and air gap thickness demonstrates a trend of first increasing significantly and then tending to stabilize, and an optimal Logistic model is established. The thermal resistance changes greatly when the inflation volume is less than 50%, and the thermal resistance gradually stabilizes when the inflation volume is greater than 50%. When the air gap thickness is around 20 mm, the inflatable fabric has the best thermal performance. This paper also confirms by experiments that the inflatable clothing fabric has temperature regulation and warm keeping performance, and there is a certain regularity of the air gap thickness and thermal resistance. The research findings provide data reference for researchers of related materials, and the overall warm keeping of inflatable clothing is affected by a variety of factors, and there is still a lot of research space that can also be used as the direction of future research.

Key words: warm keeping dothing, inflation composite fabric, inflation volume, thickness, thermal resistance