Heat insulation characteristics of high bulk nonwovens

The insulation layer is a vital component in cold weather clothing. Majority of the heat loss from the body is restricted by the insulation layer. Hence, the design of insulation layer is critical for the performance of extreme cold weather clothing. The factors which influence the thermal resistance of nonwovens' layer are fibre denier, fibre cross-section and bulk density, porosity and thickness of nonwovens. In this study, we try to optimize these parameters for high-bulk thermal bonded nonwovens using solid and hollow polyester fibres of different deniers. The effect of these parameters and their interdependency has been evaluated by suitable statistical analysis with the help of Design expert software. Contribution analysis has been carried out to ascertain the importance of thickness, areal density and fibre denier and shape. Finer and hollow fibres give better thermal insulation than the coarser and solid fibres. Nonwovens have very high porosity, especially the lighter and thinner ones have poor thermal resistance. Finer and hollow fibres due to their superior thermal insulation are ideal choice for making thinner and lightweight extreme cold weather clothing.