Hot Air Through vs. Spunbond Nonwoven: Which Top Sheet Offers Better Fluid Acquisition?

2026-07-23

In the structure of a baby diaper, the top sheet is the first barrier in direct contact with the skin. Its core functions are twofold: rapidly conducting urine into the underlying absorbent core, and minimizing rewet to maintain a dry surface. The two mainstream top sheet materials on the market are air-through nonwoven and spunbond nonwoven, each with distinct strengths in fluid acquisition performance.

1. Air-Through Nonwoven: The "Rapid Acquisition" Advantage of a Lofty Structure

Air-through nonwoven is made from bicomponent fibers bonded by hot air penetration, creating a highly porous structure with excellent loft and elasticity. This three-dimensional architecture delivers superior fluid acquisition characteristics: the voids between fibers can temporarily hold over 10 times their own weight in liquid, with excellent rewet barrier properties. In terms of acquisition speed, air-through nonwoven exhibits excellent liquid strike-through performance, with some studies showing superior overall penetration compared to conventional polyolefin-based fiber materials .

Regarding rewet control, air-through nonwoven also performs remarkably well. Its lofty structure acts as a temporary liquid reservoir, effectively blocking liquid in the core from migrating back to the surface. Research indicates air-through nonwoven has excellent rewet resistance, effectively maintaining surface dryness. Additionally, air-through nonwoven is soft with a low coefficient of friction, making it more comfortable for sensitive infant skin .

⭐2. Spunbond Nonwoven: Strength and Structural Stability

Spunbond nonwoven is made from continuous filaments formed into a web and bonded via thermal calendering or through-air methods. The fibers are densely packed, resulting in high material strength and good tear resistance . In terms of acquisition performance, spunbond nonwoven features well-developed hydrophilic treatment, good absorbency, fast multiple-strike-through rates, and a comfortable dry surface.

However, spunbond nonwoven lacks the loft of air-through materials—its inter-fiber voids are smaller, limiting its liquid temporary storage capacity. In rewet performance, if the surface layer has insufficient liquid-holding capacity, rewet under pressure may increase. Recent process and formulation improvements have significantly enhanced spunbond softness, making it still a mainstream top sheet option.

3. Comparative Summary: Which Performs Better as Top Sheet?

Performance Dimension	Air-Through Nonwoven	Spunbond Nonwoven
Loft/Thickness	High (3–5× spunbond at same basis weight)	Low
Softness	Cottony soft, low friction	Silky smooth, improved softness
Liquid Strike-Through	Excellent	Good, fast multi-strike
Rewet Resistance	Excellent	Moderate, depends on liquid-holding capacity
Strength/Deformation	Lower, easy to deform	High, good tear resistance
Cost	Higher	Lower

4. Modern Design Trend: Composite Structures

Considering overall acquisition performance, air-through nonwoven generally outperforms spunbond in both liquid strike-through speed and rewet control—which explains why more premium diapers are increasingly adopting air-through materials for their top sheet. Nevertheless, spunbond nonwoven remains an important top sheet option due to its good absorbency and higher strength.

Modern diaper design has moved beyond single-material choices. Patent innovations demonstrate that composite structures using spunbond as the upper layer and air-through as the lower layer combine the rapid penetration of spunbond with the acquisition and distribution capabilities of air-through, delivering superior overall absorption performance. For manufacturers, the selection of top sheet material should be a comprehensive decision based on product positioning, target market, and cost considerations.

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