As the age grows, the baby's activity becomes larger, and the urine also increases. Absorbing urine discharged by the baby is the main function of pull-up pants. When choosing pull-up pants, good pull-up pants usually have fast water absorption speed and 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 hundreds or even thousands of times its own weight, and has a strong water retention capacity, so it is also called super water-absorbing agent or high water-retaining agent. Fluff pulp is a kind of high-grade absorbent pulp, which is made by shredding bleached drum dry pulp board into fluff tufts in a shredder. 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 absorbs and diffuses the liquid quickly through the action of the capillary, and then the liquid in the pulp fiber is absorbed by the SAP, and the pulp returns to the dry state and then 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 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. Previous: What size baby is suitable for pull-up pants? Next: How to buy diapers?