# 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 comfort, absorption, and protection. Modern sanitary napkins combine various layers of specialized materials to provide optimal performance during menstruation.

## Core Components of Sanitary Napkin Materials

### Top Layer (Cover Stock)

The top layer, also known as the cover stock, comes in direct contact with the skin. It’s typically made from:

– Non-woven fabric (polypropylene or polyethylene)
– Perforated plastic film
– Cotton or cotton blends

This layer must be soft, breathable, and quick-drying to maintain comfort while allowing menstrual fluid to pass through to the absorbent core.

### Absorbent Core

The middle layer is the absorbent core, which primarily consists of:

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

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

### Back Sheet

The bottom layer is a waterproof barrier made from:

– Polyethylene film
– Breathable microporous films
– Biodegradable materials in eco-friendly options

This layer prevents leakage while some advanced versions allow moisture vapor to escape for better comfort.

## Additional Components

### Adhesive Strips

Most sanitary napkins include:

– Pressure-sensitive adhesive on the back sheet
– Wing adhesives for secure attachment to underwear

### Release Paper

A protective layer that covers the adhesive before use, typically made from silicone-coated paper or plastic film.

## Material Properties and Performance

### Absorption Capacity

Modern sanitary napkins can absorb between 10 to 50 times their weight in fluid, depending on:

– SAP concentration
– Core material composition
– Design structure

### Breathability

Advanced materials allow:

– Air circulation to reduce moisture buildup
– Reduced risk of irritation and odor

### Softness and Comfort

Top layer materials are designed to:

– Minimize friction
– Reduce skin irritation
– Provide a smooth surface texture

## Environmental Considerations

Recent developments include:

– Biodegradable materials
– Organic cotton options
– Chlorine-free bleaching processes
– Reduced plastic components

## Conclusion

The composition of sanitary napkin materials has evolved significantly to provide better protection, comfort, and environmental sustainability. Understanding these materials helps consumers make informed choices based on their needs and preferences.