Thermal property analysis of tri layer composite fabric towards the utility of sleeping bag

Purpose This paper aims to investigate on composite fabrics to develop the improved sleeping bag using trilayered textile structures. A thermal comfort analysis of fabrics is essential to design an enhanced type of sleeping bag. Design/methodology/approach In this study, optimizing thermal and permeability properties of different combinations of trilayer composite fabrics was done. The inner layer was 100% wool-knitted single jersey fabric. The middle layer was polyester needle punched non-woven fabric. The outermost layer was nylon-based Core-Tex branded waterproof breathable fabric. Five variations in wool-knitted samples were developed by changing the loop length and yarn count to optimize the best possible combination. Two different polyester non-woven fabrics have been produced with the changes in bulk density. Twelve trilayer composite fabric samples have been produced, and thermal comfort properties such as thermal conductivity, thermal absorptivity, thermal resistance, air permeability and relative water vapour permeability have been analysed. Findings Among the 12 samples, one optimized sample has been found with the specification of 100% wool with 25 Tex yarn linear density having 4.432-mm loop length inner-layered fabric, 96 g/m 2 polyester nonwoven fabric as the middle layer, and 220 g/m 2 Nylon-Core tex branded outermost layer. All the functional properties of the composite fabric are significantly different with the knitted wool fabrics and polyester nonwoven fabrics, which have been confirmed by analysis of variance study. Originality/value This research work supports for producing sleeping bag with enhanced comfort level.