Sanitary Napkin Core Design: Differences Between Ordinary, Ultra-Thin, and Air-Cushion Types

2026-07-27

The absorbent core of a sanitary napkin is the central component that determines product performance. Commonly available sanitary napkins can be categorized into three core structure types: Ordinary (Standard), Ultra-Thin, and Air-Cushion (Loft/Airy) . These three types differ significantly in material composition, thickness, absorption mechanism, and user experience. Understanding these differences enables purchasers to make precise product selections based on target market consumer preferences.

1. Ordinary (Standard) Type: Traditional Structure with Fundamental Absorption

The ordinary type is the most traditional and widely used product type. Its core consists of a fluff pulp and SAP blend, wrapped in tissue paper or wet-strength paper.

Characteristic	Ordinary Type Specification
Core Thickness	Approx. 3–5 mm
Absorption Layer Structure	Single layer, uniform blend
Acquisition/Distribution Design	None or simple embossed channels
Typical Absorption Capacity	80–150 ml (day) / 150–250 ml (night)
Suitable Scenarios	Moderate flow, daily wear

The advantages of the ordinary type are mature technology and lower cost, making it suitable for price-sensitive mass markets. Its disadvantages include a noticeably thicker core with a distinct "wearing" sensation; moreover, the uniformly blended SAP and fluff pulp core is prone to gel blocking —the SAP on the surface swells upon liquid absorption, forming a gel layer that hinders liquid penetration into the core, reducing overall core utilization.

2. Ultra-Thin Type: Compressed Core with Composite Structure

The ultra-thin type is one of the fastest-growing segments. Its core design philosophy differs fundamentally from the ordinary type.

The key difference: the ultra-thin type replaces traditional loose fluff pulp with a thin composite absorbent layer, typically consisting of SAP particles uniformly distributed on a thin nonwoven or paper substrate, fixed via thermal bonding or lamination, resulting in a core thickness of only 1–2 mm. Some premium ultra-thin cores adopt a multi-layer composite structure —a top rapid-acquisition layer, a middle SAP-rich retention layer, and a bottom impermeable barrier.

Characteristic	Ultra-Thin Type Specification
Core Thickness	Approx. 1–2 mm
Absorption Layer Structure	Multi-layer composite or SAP-coated nonwoven
Acquisition/Distribution Design	3D embossed distribution layer or apertured film
Typical Absorption Capacity	120–180 ml (day) / 200–300 ml (night)
Suitable Scenarios	Moderate flow, "featherlight" feel

The advantages of the ultra-thin type are superior wearing comfort, excellent discretion, and no foreign-body sensation, making it especially suitable for hot summer seasons or activities such as yoga and sports where free movement is essential. The layered SAP distribution also reduces gel blocking, leading to higher core utilization. Its disadvantages include higher cost, and some lower-end ultra-thin cores may have insufficient absorption capacity.

⭐3. Air-Cushion Type: Air Layer with Resilient Structure

The air-cushion type (also known as airy/loft type) is a newer core structure gaining traction in the mid-to-premium market. Its design draws inspiration from the "air spring" concept—incorporating an air pocket layer within the core that provides both elasticity and cushioning.

A typical air-cushion core consists of three layers:

Top layer: Soft nonwoven topsheet for rapid penetration
Middle layer: Lofty air pocket (made of low-density hollow fibers or coarse-denier bulky fibers forming an elastic support structure) that compresses under pressure and recovers when released, maintaining core shape stability
Bottom layer: SAP absorbent layer responsible for liquid retention

Characteristic	Air-Cushion Type Specification
Core Thickness	Approx. 4–8 mm (lofty) / 2–3 mm (compressed)
Absorption Layer Structure	Air pocket + SAP absorption layer composite
Acquisition/Distribution Design	Elastic support structure with zoned SAP
Typical Absorption Capacity	100–150 ml (day) / 200–280 ml (night)
Suitable Scenarios	All flow levels, soft feel with shape retention

The advantages of the air-cushion type are exceptional softness, superior tactile feel, rapid thickness recovery after compression, and resistance to deformation. The air pocket also facilitates micro-circulation of air within the core, reducing heat and moisture buildup. Its disadvantages include the highest production cost, and at equivalent thickness, its absorption capacity is slightly lower than that of a compressed core of similar volume.

4. Comprehensive Comparison of the Three Core Types

Comparison Dimension	Ordinary	Ultra-Thin	Air-Cushion
Core Thickness	3–5 mm	1–2 mm	4–8 mm (lofty)
Absorption Capacity	Medium	Medium-High	Medium
Wearing Comfort	Moderate	Excellent	Excellent
Anti-Gel Blocking	Moderate	Good	Good
Shape Retention	Moderate (prone to deformation)	Good	Excellent (elastic recovery)
Production Cost	Low	Medium-High	High
Target Market Positioning	Economy/Mass Market	Mid-to-Premium Lightweight	Mid-to-Premium Comfort

5. Procurement Recommendations

When selecting core types, purchasers should consider target market consumer usage habits and preferences:

Price-sensitive markets or large-volume public procurement: The ordinary type remains the most cost-effective choice.
Younger female consumer segments or hot-climate markets: The ultra-thin type, with its featherlight feel, offers stronger competitiveness.
Premium markets or sensitive-skin users: The air-cushion type, with its soft feel and shape retention, can serve as a key differentiating selling point.

By reviewing the core structure description (materials, layers, thickness) and absorption capacity test data in the technical specification sheet, purchasers can accurately assess product performance and make selection decisions that best match market demand.

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