Baby diapers are just a thin layer, yet they can absorb several rounds of a baby's urine. No matter how much the baby wriggles or squirms, the urine doesn't leak out from inside the diaper. So, what is the principle behind how baby diapers absorb urine?

Below, Hongfutai will give you a quick science lesson on the structure of baby diapers:

The super-absorbent baby diapers and it water-retention capabilities are thanks to their absorbent materials and structural design.

1. Baby diapers generally have a four-layer structure:

1. Top sheet: Made of non-woven fabric, it comes into direct contact with the baby's skin, receives urine, and transfers it to the next layer.

2. Distribution layer: Also made of non-woven fabric, it evenly distributes the urine received from the top sheet to the absorbent core.

3. Absorbent core: Composed of super absorbent polymer (SAP) mixed with fluff pulp, or sometimes pure SAP without fluff pulp. This is the most important functional layer in the diaper, responsible for absorbing and storing urine.

4. Backsheet: Made of PE film or PE film combined with non-woven fabric. It is breathable but waterproof, primarily make it leak protection baby diapers.

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2. Let’s talk about the absorbent material inside baby diapers—super absorbent polymer (SAP).

Many moms mistakenly think that baby diapers contain cotton to absorb urine. But if you peel back the top layer of a diaper, you’ll find tiny bead-like particles mixed with fluff fibers. This is the secret behind the diaper’s high absorbency.

Super absorbent polymer (SAP) is a typical functional polymer material. SAP looks like tiny beads, only about 0.2mm in diameter, and can absorb hundreds or even thousands of times its own weight in water while maintaining strong water retention. In most ordinary diapers, the SAP in the absorbent core is evenly mixed with fluff pulp!

3. How baby diapers lock in moisture:

When SAP comes into contact with water or other liquids, its porous structure rapidly absorbs the liquid, locking it inside and forming a gel-like state. This gel stabilizes the liquid, prevents back flow, and keeps the dry surface diapers.

Although SAP has powerful water-locking and retention abilities, it does have its limits! Hongfutai kindly reminds you: leaving a diaper on for too long can exceed SAP’s capacity, leaving your baby’s bottom soaked in urine and potentially causing diaper rash! So, always pay attention to the wetness indicator and change diapers promptly based on your baby’s urination patterns!