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# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential hygiene products used by women during menstruation. Understanding the raw materials used in their production is crucial for ensuring comfort, 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 most critical component of a sanitary napkin. It is responsible for absorbing and retaining menstrual fluid. The primary materials used in the absorbent core include:

– **Wood Pulp**: Wood pulp is a natural fiber that provides excellent absorbency. It is often blended with other materials to enhance its performance.
– **Super Absorbent Polymers (SAP)**: SAPs are synthetic materials that can absorb and retain large amounts of liquid relative to their mass. They are highly effective in maintaining dryness and preventing leakage.

## 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 transfer to the absorbent core. Common materials used for the top sheet include:

– **Nonwoven Fabrics**: These are made from synthetic fibers such as polypropylene or polyester. They are designed to be soft, breathable, and quick-drying.
– **Perforated Films**: Some sanitary napkins use perforated plastic films as the top sheet. These films are designed to 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 for the back sheet include:

– **Polyethylene Films**: These are thin, flexible plastic films that are impermeable to liquids. They provide an effective barrier against leakage.
– **Breathable Films**: Some advanced sanitary napkins use breathable films that allow air to pass through while still preventing liquid leakage. This helps in reducing the risk of skin irritation and discomfort.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin to the underwear. The adhesive must be strong enough to hold the napkin in place but gentle enough to avoid damaging the fabric. Common types of adhesives include:

– **Hot Melt Adhesives**: These are thermoplastic adhesives that are applied in a molten state and solidify upon cooling. They provide a strong bond and are commonly used in sanitary napkins.
– **Pressure-Sensitive Adhesives**: These adhesives form a bond when pressure is applied. They are easy to apply and remove, making them ideal for sanitary napkins.

## 5. Release Paper

Release paper is used to cover the adhesive before the sanitary napkin is used. It is typically made from silicone-coated paper or film, which allows it to be easily peeled off without leaving residue.

## Properties of Sanitary Napkin Raw Materials

The raw materials used in sanitary napkins must possess specific properties to ensure the product’s effectiveness and user comfort:

– **Absorbency**: High absorbency is crucial for managing menstrual flow effectively.
– **Softness**: The materials must be soft to prevent irritation and ensure comfort during use.
– **Breathability**: Breathable materials help in reducing the risk of skin irritation and discomfort.
– **Leakage Prevention**: The materials must provide an effective barrier against leakage to maintain hygiene.
– **Biodegradability**: With increasing environmental concerns, biodegradable materials are becoming more popular in sanitary napkin production.

In conclusion, the raw materials used in sanitary napkins play a vital role in determining their performance, comfort, and safety. By understanding the composition and properties of these materials, manufacturers can produce high-quality sanitary napkins that meet the needs of users while also addressing environmental concerns.