# Sanitary Napkin Material: Composition and Properties

## Introduction to Sanitary Napkin Materials

Sanitary napkins are essential feminine hygiene products designed to absorb menstrual flow. The materials used in their construction play a crucial role in their effectiveness, comfort, and safety. Modern sanitary napkins combine various components to achieve optimal absorption, leak protection, and skin comfort.

## Core Components of Sanitary Napkins

### 1. Top Sheet (Cover Layer)

The top sheet is the layer that comes in direct contact with the skin. It’s typically made from:

– Non-woven polypropylene (most common)
– Perforated plastic film
– Cotton or cotton blends (for premium products)

Key properties: Softness, quick-drying, breathability, and smooth texture to prevent irritation.

### 2. Absorbent Core

This is the central layer responsible for fluid absorption. It usually consists of:

– Fluff pulp (wood cellulose)
– Superabsorbent polymers (SAP)
– Sometimes blended with cotton or rayon

The SAP can absorb many times its weight in liquid, transforming it into gel to prevent leakage.

### 3. Back Sheet

The bottom layer prevents leaks and protects clothing. Materials include:

– Polyethylene film (most common)
– Breathable microporous films
– Biodegradable materials in eco-friendly options

This layer must be waterproof yet comfortable against clothing.

### 4. Adhesive Layer

A pressure-sensitive adhesive strip keeps the napkin in place on underwear. It’s typically:

– Hot melt adhesive
– Latex-free for sensitive skin
– Designed to be strong yet removable without residue

## Additional Features in Modern Designs

### Wings

Many napkins feature side wings made of:

– Non-woven material
– Sometimes with additional adhesive

These help secure the pad and prevent side leakage.

### Odor Control

Some products incorporate:

– Activated charcoal layers
– Baking soda
– Fragrance (though this may cause irritation for some users)

## Material Properties and Performance

### Absorption Capacity

Measured in grams of fluid absorbed, influenced by:

– SAP concentration
– Fluff pulp density
– Core design

### Breathability

Important for skin health, affected by:

– Top sheet material
– Back sheet porosity
– Overall thickness

### Skin Safety

Materials should be:

– Hypoallergenic

– Free from harmful chemicals
– Dermatologically tested

## Environmental Considerations

Recent developments include:

– Biodegradable materials
– Organic cotton options
– Reduced plastic content
– Compostable designs

## Conclusion

The materials in sanitary napkins have evolved significantly, balancing absorption, comfort, and safety. Understanding these components helps consumers make informed choices based on their needs and preferences, whether prioritizing performance, skin sensitivity, or environmental impact.