Abstract
Thermal transmittance of bedding materials wes measured to study the relation of the thermal retaining properties with bulk density and thickness by using the ASTM apparatus.The materials are silk, ramie, china glass which have hardly been studied, besides cotton, polyester, wool-polyester blend and urethan-foam.
Results are :
1) Cotton and silk show the highest thermal retaining property at 0.04 g/cm3 in bulk density and urethan-foam at 0.03 to 0.2 g/cm3 in bulk density.
2) Urethan-foam in small bulk density shows higher thermal retaining property when the surface is covered with cloth than no cloth. In this case, the cover may prevent the thermal air current.
3) The thicker the material is, the higher the thermal retaining coefficient is. However, when the thickness is 5-6 cm the coefficient increases if two surfaces of the material are covered with cloth.
4) When the bulk densities of the materials are same, silk and urethan-foam are good thermal retainers, but ramie and china glass poor.
