The absorption principle of diapers | Newclears

There will have many people confused that why a small diapers can absorb the much urine and do not leak? This is related to the structure of the diaper. Let's take a look at the structure of the diaper.

Diapers typically have 4 layers:

1. Top sheet: normally made of non-woven fabric, directly against the skin, absorbing urine and transferring it to the next layer.
2. Acquisition distribution layer(ADL): made of non-woven fabric, it evenly transfers the liquid received by the surface layer to the absorption layer. This is not a mandatory option and can be added based on the customer's budget and absorption effect requirements.

Absorption layer: made of super absorbent polymer(SAP), cover with non-woven fabric to prevent SAP leakage, it’s the most important functional layer in the diapers, used to absorb and store urine. The water absorption of diapers is closely related to the quality of SAP.

SAP is a typical functional polymer material. It is shaped like small beads with a diameter of only about 0.2mm. It can absorb hundreds or even thousands of times its own weight in water and has a strong water retention capacity, so it is also called super absorbent or high water retention agent.

The reason why SAP has such strong water absorption capacity is that super absorbent resin is a low cross-linked or partially crystalline high molecular polymer with many hydrophilic groups. When the SAP particle size is 100-120 mesh (i.e. 0.212mm-0.254mm), the absorption capacity is the best; when the pH value is 6-8, the absorption rate is the highest.

1. Back sheet: made of PE film or PE film + non-woven fabric, the main function is prevent the urine leak from the diapers. Many customers choose to print some patterns on PE film to highlight their brand logo. Printed diapers are more beautiful.

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