# 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 Stock)

The top layer that comes in direct contact with the skin is typically made from:

– Nonwoven polypropylene or polyethylene
– Perforated plastic films
– Cotton or cotton blends for premium products

This layer is designed to be soft, breathable, and quickly transfer liquid to the absorbent core while keeping the surface dry.

### 2. Absorbent Core

The middle layer responsible for fluid absorption consists of:

– Fluff pulp (wood cellulose)
– Superabsorbent polymers (SAP)
– Combination of both materials

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

### 3. Back Sheet

The bottom layer is usually made from:

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

This layer prevents leakage while allowing some breathability in premium products.

### 4. Adhesive Components

Sanitary napkins include:

– Pressure-sensitive adhesive strips to secure the pad to underwear
– Release paper to protect the adhesive before use

## Material Properties and Performance

### Absorption Capacity

Modern sanitary napkins can absorb between 10-20 times their weight in fluid, depending on:

– SAP concentration
– Fluff pulp density
– Core design and distribution

### Breathability

High-quality pads feature:

– Microporous back sheets
– Air-permeable top sheets
– Channeled cores for better air circulation

### Skin Safety

Materials are selected for:

– Hypoallergenic properties
– pH balance maintenance
– Reduced friction and irritation

## Environmental Considerations

Recent developments include:

– Biodegradable and compostable materials
– Organic cotton options
– Reduced plastic content
– Plant-based SAP alternatives

Manufacturers continue to innovate with sustainable materials while maintaining performance standards for this essential hygiene product.