Fluff Pulp vs. SAP Ratio: How We Optimize the Core for Maximum Leakage Protection

⭐2. Gradient Ratio Design: Layered Architecture for Synergistic Performance

Modern high-end diapers have moved beyond simple homogeneous mixing toward gradient ratio layered design. A typical three-layer configuration includes:

• Top layer (liquid acquisition layer): Higher fluff pulp content with a small amount of SAP. Positioned close to the top sheet, it prioritizes rapid absorption and longitudinal liquid spreading, preventing local accumulation.

• Middle layer (liquid distribution and temporary storage): Fluff pulp and SAP mixed at a medium ratio. It spreads liquid laterally across the core plane, ensuring uniform distribution and preventing localized saturation.

• Bottom layer (terminal liquid-locking layer): Significantly higher SAP content, reaching 60%–70% by mass in some premium formulations. Located farthest from the skin, it serves as the final barrier to prevent liquid from migrating back to the surface under pressure.

In addition to layered architecture, zonal SAP application technology can be employed—increasing SAP dosage in the central absorption zone while reducing it at the edges with more fluff pulp. The center strengthens liquid retention against concentrated urine impact, while the edges maintain softness through the fiber network and minimize side-leakage pathways.