# 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 and safety. This article delves into the composition and properties of the primary materials used in sanitary napkins.

## 1. Absorbent Core

The absorbent core is the most critical component of a sanitary napkin, responsible for absorbing menstrual fluid. It is typically made from a blend of the following materials:

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

– **Nonwoven Fabrics**: Made from synthetic fibers like polypropylene or polyester, nonwoven fabrics are lightweight, breathable, and provide a smooth surface.
– **Perforated Film**: Some sanitary napkins use a thin, perforated plastic film as the top sheet, which allows for rapid liquid absorption 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 external moisture. Materials used for the back sheet include:

– **Polyethylene Film**: A common choice due to its waterproof properties and flexibility. It is also lightweight and cost-effective.
– **Breathable Microporous Film**: This material allows for air circulation, reducing the risk of skin irritation and 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 of adhesives include:

– **Hot Melt Adhesives**: These are applied in a molten state and solidify upon cooling, providing a strong bond.
– **Pressure-Sensitive Adhesives**: These adhesives form a bond when pressure is applied, making them easy to use and reposition.

## 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 easy to peel off and does not leave residue on the adhesive.

## Properties of Sanitary Napkin Materials

The materials used in sanitary napkins must possess specific properties to ensure optimal performance and user comfort:

– **Absorbency**: The ability to quickly absorb and retain menstrual fluid is paramount. Materials like wood pulp and SAP are chosen for their high absorbency.
– **Softness**: The top sheet must be soft and gentle on the skin to prevent irritation and discomfort.
– **Breathability**: Materials that allow air circulation help reduce the risk of skin irritation and maintain comfort.
– **Leakage Prevention**: The back sheet and absorbent core must work together to prevent any leakage, ensuring the user remains dry and confident.
– **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 effectiveness and user satisfaction. By understanding these materials, manufacturers can continue to innovate and improve the quality of these essential products.