Modern disposable diapers combine nonwoven fabrics, cellulose fluff pulp, superabsorbent polymers, plastic films, elastics, and adhesives. Each material performs a different function in liquid absorption, leakage prevention, fit, and comfort.

What Are the Main Materials Used in Disposable Diapers?

A disposable diaper is a multilayer hygiene product. Its performance depends on how different materials work together rather than on one absorbent component alone.

The main materials commonly used include:

• Polypropylene nonwoven fabric.

• Polyethylene film.

• Cellulose fluff pulp.

• Superabsorbent polymer.

• Polyester fibers.

• Elastic materials and adhesives.

The exact material combination varies according to diaper design, absorbency requirements, product positioning, and manufacturing processes.

What Materials Are Used in Each Diaper Layer?

1. Topsheet: Polypropylene and Other Nonwoven Fibers

The topsheet is the inner layer that comes into contact with the skin.

It is commonly made from soft polypropylene nonwoven fabric, although other fibers and material combinations may also be used.

Its main functions are to:

• Allow liquid to pass through quickly.

• Provide a soft contact surface.

• Reduce the feeling of surface wetness.

• Maintain suitable fabric strength during use.

The topsheet should transfer liquid into the underlying absorbent structure without creating unnecessary surface moisture.

2. Acquisition and Distribution Layer: Functional Nonwoven Materials

The acquisition and distribution layer, commonly called ADL, sits beneath the topsheet.

It helps receive liquid and distribute it across a wider area of the absorbent core.

Polypropylene, polyester, and other synthetic fiber combinations may be used depending on the product design.

A properly designed ADL helps prevent liquid from accumulating in one small area and improves the utilization of the absorbent core.

3. Absorbent Core: Fluff Pulp and Superabsorbent Polymer

The absorbent core is the main liquid-storage component of a disposable diaper.

It commonly combines cellulose fluff pulp and superabsorbent polymer, also known as SAP.

Fluff Pulp

Fluff pulp is generally produced from processed cellulose fibers, commonly derived from wood pulp.

It helps absorb and distribute liquid throughout the core structure.

Superabsorbent Polymer

SAP is a highly absorbent material, commonly based on sodium polyacrylate.

When it comes into contact with liquid, it swells and forms a gel-like structure that retains moisture.

The balance between fluff pulp and SAP influences absorbency, core thickness, liquid distribution, and finished product performance.

Some diaper designs also use tissue paper, air-laid paper, or composite core sheets to improve structural stability.

4. Backsheet: Polyethylene Film and Composite Materials

The backsheet is the outer barrier layer of a disposable diaper.

Polyethylene film is commonly used because it helps prevent liquid from leaking onto clothing or bedding.

Some products use a breathable film or a film-and-nonwoven composite to improve moisture vapor transmission and outer surface feel.

The material must provide suitable liquid resistance while remaining compatible with the overall diaper structure.

5. Elastic Components and Fastening Materials

A diaper also contains several functional components beyond its main layers.

These may include:

• Spandex or other elastic materials around the waist and legs.

• Standing leak guards.

• Side panels and fastening tabs.

• Frontal tape and hook-and-loop fastening systems.

• Adhesives for bonding different layers.

These components help maintain fit, prevent leakage, and keep the diaper assembled during use.

How Does Material Selection Affect Diaper Performance?

Material selection directly influences the finished product.

For example, a diaper with a suitable absorbent core but poor liquid distribution may develop localized swelling.

An unsuitable backsheet may increase leakage risk, while inconsistent elastic application can affect the fit around the waist and legs.

Manufacturers should evaluate several factors together:

Absorption Capacity

The amount and distribution of fluff pulp and SAP influence liquid retention.

Liquid Distribution

The ADL and core structure determine how liquid spreads through the absorbent area.

Surface Dryness

Topsheet properties and core absorption influence the amount of moisture remaining near the skin.

Structural Stability

Core bonding, lamination, and material positioning help maintain the diaper's shape.

Fit and Leakage Control

Elastic tension, cuff dimensions, and fastening strength influence how well the product fits the user.

How Are These Materials Processed During Diaper Manufacturing?

Disposable diaper production requires multiple material feeding and converting processes.

A typical manufacturing sequence includes:

1. Nonwoven fabric and film unwinding.

2. Fluff pulp preparation and feeding.

3. SAP metering and distribution.

4. Absorbent core forming.

5. Layer lamination and bonding.

6. Elastic and leak-guard application.

7. Fastening component positioning.

8. Cutting and shaping.

9. Folding and inspection.

10. Counting and packaging.

Each process needs to remain coordinated.

For example, inaccurate SAP feeding can create uneven core weight, while unstable web tension may affect material alignment and finished product dimensions.

What Equipment Is Used to Produce Diaper Absorbent Core Materials?

The absorbent core preparation stage is particularly important because it determines how pulp, SAP, and supporting materials are combined.

Our FH12B Diaper Composite Core Production Machine is designed for processing materials such as:

• Spunlace nonwoven.

• Spunbond nonwoven.

• Hot-air nonwoven.

• Fluffy nonwoven.

• Air-laid paper.

• SAP.

Its published specifications include a maximum design speed of 150 m/min, a normal working speed of 20–120 m/min, and SAP spreading accuracy deviation within ±2%.

The machine supports automatic material connection and replacement, as well as online slitting and winding.

For diaper manufacturers, controlled SAP feeding and stable composite formation help reduce material variation before the core enters downstream diaper assembly.

How Does SAYA Support Diaper Material Processing?

SAYA focuses on intelligent equipment for hygiene material manufacturing, flexible packaging, and related converting applications.

Our engineering team considers material characteristics, SAP dosage, composite structure, web tension, and production requirements when developing equipment configurations.

We support equipment projects for diaper factories, absorbent core manufacturers, and hygiene product producers.

Explore Better Material Processing for Diaper Production

Share your intended diaper structure, raw materials, SAP requirements, production width, and target output with our team to discuss suitable absorbent core processing equipment and customized manufacturing solutions.