Using the compression properties of pillows to estimate sleeping comfort

In order to establish an objective method of evaluating pillow comfort, we investigate the relation between the sensory evaluation of pillows and the compression properties of pillows. The subjective evaluation values of hardness, fitness and total comfort were correlated with the compression energy WC and the displacement Δ T at the maximum load of 50gf/cm². Pillows which have large values of WC and Δ T were regarded as softer, fitter and more comfortable. Pillows estimated as being soft and fit showed larger contact areas and less contact pressure on the head. For the pillows which have the same flat shape, a good agreement between the individual judges was shown in the assessments of hardness and height. The shape and packing density of polyethylene pipes affected the degree of the hardness of the pillows.