# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential feminine hygiene products designed to provide comfort and protection during menstruation. Understanding the raw materials used in their production is crucial for ensuring quality, safety, and effectiveness. 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 absorbing 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 crucial for preventing leakage and maintaining dryness.

## 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 soft to the touch.
– **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 of the sanitary napkin, designed to prevent leakage and provide a barrier against moisture. Materials used include:

– **Polyethylene (PE) Films**: These are waterproof and provide an effective barrier against leaks. They are also flexible and comfortable to wear.
– **Breathable Films**: These films allow air to pass through while still preventing liquid leakage, enhancing comfort and reducing the risk of skin irritation.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin in place. They must be strong enough to hold the pad 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 the wings of sanitary napkins.

## 5. Release Paper

Release paper is used to protect the adhesive before use. It is typically made from:

– **Silicone-Coated Paper**: This paper is treated with silicone to prevent the adhesive from sticking to it, allowing for easy removal when the napkin is ready to be used.

## Properties of Sanitary Napkin Materials

The materials used in sanitary napkins must possess specific properties to ensure they perform effectively:

– **Absorbency**: The ability to quickly absorb and retain menstrual fluid is crucial for preventing leaks and maintaining comfort.
– **Softness**: Materials that come into contact with the skin must be soft to prevent irritation and discomfort.
– **Breathability**: Good air circulation helps reduce the risk of skin irritation and keeps the user feeling fresh.
– **Flexibility**: The materials should be flexible to conform to the body’s shape, providing a comfortable fit.
– **Biodegradability**: With increasing environmental concerns, there is a growing demand for biodegradable materials that minimize environmental impact.

In conclusion, the composition and properties of the raw materials used in sanitary napkins play a vital role in their performance and user satisfaction. By understanding these materials, manufacturers can produce high-quality products that meet the needs of consumers while also considering environmental sustainability.