# 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 long-lasting dryness.

## 2. Top Sheet

The top sheet is the layer that comes into direct contact with the skin. It must be soft, comfortable, and quick-drying. Common materials used include:

– **Nonwoven Fabrics**: These are made from synthetic fibers like polypropylene or polyester. They are designed to be soft, breathable, and moisture-wicking.
– **Perforated Films**: Some sanitary napkins use perforated plastic films as the top sheet, which allows for quick liquid absorption while maintaining a dry surface.

## 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 thin, flexible, and waterproof, making them ideal for preventing leaks.
– **Breathable Films**: Some high-end sanitary napkins use breathable films that allow air to circulate while still providing a moisture barrier.

## 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 are designed to adhere upon application of light pressure and are commonly used for their ease of use and reliability.

## 5. Release Paper

Release paper is used to protect the adhesive before the sanitary napkin is used. 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 to circulate to reduce the risk of skin irritation and odor.
– **Leakage Prevention**: The back sheet and adhesive must work together to prevent any leakage, ensuring the user remains dry and comfortable.
– **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 the raw materials used in sanitary napkins are critical to their performance and user satisfaction. By understanding these materials, manufacturers can continue to innovate and improve the quality of these essential products.