Changes in Disposable Diaper Properties Caused by Wetting

Abstract

Changes caused by wetting in the compression, surface, and heat transfer properties of forty-nine commercial disposable diapers are investigated to clarify their performance in use. In the tests, a segment cut from the center of a diaper is moistened with 0.9% NaCl solution, and the hand of the wet diaper is assessed and compared with dry ones by mothers and female students. After wetting, the diaper samples become harder due to increased compression linearity, and the recovery decreases due to decreased compres sional resilience (RC). Increases in the coefficient of friction ( MIU), surface roughness ( SMD), thermal conductance ( K'), and maximum heat flux result in a lack of smoothness and reduced warmth. The diapers evaluated as having good hand in both dry and wet conditions show small mean deviations of MIU, SMD, and K', and large RC in the dry test. These diapers also show small rewet values (large water retention). The range of the values is clarified for the diaper properties that are estimated to provide good hand.