With the increase of age, the baby's activity becomes larger, and the urine also increases. Absorbing the urine discharged by the baby is the main function of pull-up pants. When choosing pull-up pants, good pull-up pants usually absorb water quickly and have large absorption capacity, and the absorbent core layer is the key structural part of the pull-up pants. The absorbent core layer is mainly composed of non-woven material (non-woven fabric) wrapped SAP and fluff pulp mixture. SAP is a polymer water-absorbing resin, which can absorb water hundreds or even thousands of times its own weight, and has a strong water retention capacity, so it is also called a water-absorbing agent or a high water-retaining agent. Fluff pulp is a kind of high-grade absorbent pulp, which is made by shredding bleached dry pulp board in a shredder into tufts of fluff. It mainly acts as a conveying pipe in the absorbent core layer.
The principle of absorbing liquid in pull-up pants (or diapers) is as follows. First, the fluff pulp quickly absorbs and diffuses the liquid through the action of the capillary tube, and then the liquid in the pulp fiber is absorbed by the SAP, and the pulp returns to a dry state for the next liquid absorption. , And SAP forms a colloid after absorbing urine, even under external pressure, it can lock the liquid from being squeezed out. To judge the quality of the pull-up pants or the water absorption capacity, it is not accurate to directly observe the thickness of the diaper or to compare the polymer absorbent resin.