Effect of fit on heat and moisture transfer in disposable diapers for babies

Abstract

Diapers with various sizes can provide a variety of options for babies of different ages and weights, but at the same time, their “many to many” diaper sizing system, which classifies diapers only according to the baby’s growing stage and weight, also brings decision-making problems to consumers. As a kind of special clothing, diaper fit will affect its heat and moisture properties and microclimate to some extent, causing differences in the thermal and moisture comfort of babies. The aim of this paper was to investigate the effect of fit on heat and moisture transfer in the diaper under dry conditions by baby manikin tests. The following conclusions were drawn. (i) The influence of diaper fit on its thermal insulation depended on the combined effect of convective heat transfer in the waist air gap and conductive heat transfer in the crotch air gap, which was related to the waist ease allowance and the crotch length of the diaper. In particular, the waist ease allowance of tape diapers would be affected by the wearing operations of caregivers. (ii) Under dry conditions before urination, the standing posture was cooler and more comfortable than supine for babies, at approximately 0.9°C lower in microclimate temperature underneath the diaper. This was mainly due to a substantial decrease in thermal insulation of the back waist and buttocks, which were 70.86% and 79.46%, respectively. (iii) The microclimates underneath the regular pants type and loose tape type were closest to the ideal comfortable zone, and this advantage was more obvious when the baby was lying on its back. Meanwhile, the temperature and humidity inside these two types of diapers were more stable and least effected by posture changes of babies.