# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential personal care products designed to provide comfort and hygiene during menstruation. Understanding the raw materials used in their production is crucial for ensuring quality, safety, and environmental sustainability. This article delves into the composition and properties of the primary materials used in sanitary napkins.

## 1. Absorbent Core

The absorbent core is the heart of a sanitary napkin, responsible for retaining menstrual fluid. It is typically made from a combination of the following materials:

– **Wood Pulp**: A natural, biodegradable material that provides excellent absorbency. It is often blended with synthetic fibers to enhance performance.
– **Superabsorbent Polymers (SAP)**: These are synthetic materials that can absorb and retain large amounts of liquid relative to their own mass. SAPs are highly effective in preventing leakage.

## 2. Top Sheet

The top sheet is the layer that comes into direct contact with the skin. It must be soft, comfortable, and allow for quick liquid penetration. Common materials include:

– **Nonwoven Fabrics**: Made from synthetic fibers like polypropylene or polyester, nonwoven fabrics are lightweight, breathable, and provide a smooth surface.
– **Perforated Films**: These are thin plastic films with tiny holes that allow liquid to pass through while keeping the surface dry.

## 3. Back Sheet

The back sheet is the outermost layer that prevents leakage and protects clothing. It is usually made from:

– **Polyethylene (PE) Film**: A waterproof, flexible material that provides a barrier against leaks.
– **Breathable Microporous Films**: These films allow moisture vapor to escape while preventing liquid from passing through, enhancing comfort.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin in place. They must be strong enough to hold the napkin in position but gentle enough to avoid skin irritation. Common types include:

– **Hot Melt Adhesives**: These are applied in a molten state and solidify upon cooling, providing a strong bond.
– **Pressure-Sensitive Adhesives**: These adhesives stick to surfaces upon application of light pressure and are commonly used for wings and tabs.

## 5. Fragrance and Additives

Some sanitary napkins include fragrances or additives to mask odors or provide additional comfort. However, these components can sometimes cause skin irritation or allergic reactions, so their use is often debated.

## Properties of Sanitary Napkin Materials

– **Absorbency**: The ability to quickly absorb and retain menstrual fluid is crucial for preventing leaks and ensuring comfort.
– **Softness**: Materials must be gentle on the skin to avoid irritation, especially during prolonged use.
– **Breathability**: Good air circulation helps prevent moisture buildup, reducing the risk of bacterial growth and discomfort.
– **Biodegradability**: With increasing environmental concerns, there is a growing demand for materials that are biodegradable and eco-friendly.

In conclusion, the composition and properties of sanitary napkin materials play a vital role in their performance and user satisfaction. By understanding these elements, manufacturers can continue to innovate and improve the quality of these essential products.