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# 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 raw 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 materials to enhance performance.
– **Superabsorbent Polymers (SAP)**: These are synthetic materials capable of absorbing and retaining 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 allow for quick liquid penetration. Common materials include:

– **Nonwoven Fabrics**: Made from synthetic fibers like polypropylene or polyester, nonwoven fabrics are lightweight, breathable, and gentle on the skin.
– **Perforated Films**: These are thin plastic films with tiny holes that allow liquid to pass through quickly 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 Films**: These are thin, flexible plastic films that are impermeable to liquids, ensuring that menstrual fluid does not leak through.
– **Breathable Films**: Advanced back sheets made from microporous films that allow air to pass through while blocking liquids, enhancing comfort and reducing the risk of skin irritation.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin in place within 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 thermoplastic adhesives that 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 if necessary.

## 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 pad is ready to be used.

## Properties of Sanitary Napkin Raw Materials

The raw materials used in sanitary napkins must possess specific properties to ensure optimal performance:

– **Absorbency**: High absorbency is crucial for preventing leakage and maintaining dryness.
– **Softness**: Materials must be soft and gentle to avoid skin irritation and ensure comfort.
– **Breathability**: Breathable materials help reduce the risk of skin irritation and discomfort by allowing air to circulate.
– **Flexibility**: Flexible materials ensure that the pad conforms to the body’s shape, providing a secure fit.
– **Biodegradability**: Increasingly, manufacturers are opting for biodegradable materials to reduce environmental impact.

In conclusion, the composition and properties of raw materials used in sanitary napkins play a vital role in their effectiveness and user comfort. By understanding these materials, manufacturers can continue to innovate and improve the quality of feminine hygiene products, ensuring they meet the needs of women worldwide.