# 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 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 ensuring 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**: These are made from synthetic fibers like polypropylene or polyester. They are lightweight, breathable, and provide a smooth surface.
– **Perforated Films**: Some sanitary napkins use perforated plastic films as the top sheet, which allows for rapid liquid transfer while maintaining a dry surface.

## 3. Back Sheet

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

– **Polyethylene Film**: A waterproof material that provides a barrier against leaks. It is often embossed or textured to improve grip and prevent slipping.
– **Breathable Films**: Some high-end sanitary napkins use breathable back sheets that allow air circulation while still being waterproof, enhancing comfort.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin to the underwear. They must be strong enough to hold the pad in place 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 adhere to surfaces upon application of light pressure and are commonly used for their ease of use and reliability.

## 5. Release Paper

Release paper is a protective layer that covers the adhesive before use. It is typically made from:

– **Silicone-Coated Paper**: This type of 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 paramount. This is primarily achieved through the absorbent core and SAPs.
– **Softness**: The top sheet must be soft and gentle on the skin to prevent irritation and discomfort.
– **Breathability**: Materials should allow air circulation to reduce the risk of bacterial growth and odor.
– **Leakage Protection**: The back sheet and adhesive must work together to prevent leaks and keep the napkin securely in place.
– **Biodegradability**: With increasing environmental concerns, there is a growing demand for biodegradable materials that minimize environmental impact.

In conclusion, the composition and properties of sanitary napkin raw materials are carefully selected to ensure comfort, safety, and effectiveness. Advances in material science continue to improve the performance and sustainability of these essential products.