The current standard reviews the basic use performance of baby diapers, but the water transfer process between single-layer fabrics and multi-layer fabrics is still unclear due to the current limitations of various factors. Understanding the dynamic process of water transfer within baby diapers can help improve the overall design of materials and structures. It also provides insight into the generation and transfer of heat as water diffuses and passes through, and helps to investigate wearing comfort.

1.Dynamic moisture analysis

At present, the liquid water management system (MMT) is mainly used to evaluate the dynamic moisture transfer ability of textile fabrics. The tester captures 10 indicators (upper and lower surface humidity time, moisture absorption rate, maximum humidity radius, diffusivity, unidirectional transfer index, liquid water dynamic transfer index, etc.), outputs the curve of fabric moisture content over time, and quantitatively observes single-layer fabrics and water transfer and diffusion processes between multi-layer fabrics. This method is included in the test standard by the American Association of Textile Chemical Colorists (AATCC). The corresponding test standards in my country are the entry-exit inspection and quarantine industry standard SN/T1689.1-2005 "Determination of the dynamic transfer performance of porous materials in liquid water - Part 1: Textiles".

However, some scholars believe that the filling of baby nappySAP makes its own composition structure very different from ordinary fabrics. The MMT indicator system is not entirely suitable for evaluating baby nappy water management capabilities. Therefore, the researchers screened and redefined the dynamic water transfer characteristics of surface wetness time, maximum water content, retention, ponding rate, permeability, and overall water management capacity; then, through stepwise regression analysis, their five indicators were The evaluation index of management ability.

In addition, some scholars have used the color brine dynamic image analysis system to study the water transfer behavior of baby nappy, which can objectively evaluate the diffusion characteristics of liquid water in the vertical and horizontal directions.

2.Static Moisture Analysis

In the research on the optimal design of the diversion layer structure, the researchers tested the absorption rate of infant baby nappy with different diversion layer structures with reference to GB/T8939-2008 "Sanitary Napkins (including Sanitary Pads)", and also measured more than baby nappy The amount of secondary permeation and re-seepage, the infiltration time of permeate liquid, and the diffusion time of multiple permeation are discussed, and the performance differences between different diversion layer structures and materials are discussed. The structure of the diversion layer can make the liquid penetrate quickly and reduce the penetration, but the diffusion performance is poor, the core utilization rate is low, and the surface bump and punching structure can increase the vertical and vertical diffusion of the liquid. Based on this data, the authors designed a specially structured composite diversion layer to balance the longitudinal and vertical diffusion of the liquid.