# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins, also known as sanitary pads, are essential feminine hygiene products designed to absorb menstrual flow. 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.

## Core Absorbent Material

The core of a sanitary napkin is typically made from a blend of wood pulp and superabsorbent polymers (SAP). Wood pulp provides excellent absorbency and helps in distributing the menstrual fluid evenly. SAP, on the other hand, can absorb and retain large amounts of liquid relative to its own mass, ensuring that the napkin remains dry and comfortable.

### Wood Pulp

Wood pulp is a natural material derived from trees. It is highly absorbent and biodegradable, making it an environmentally friendly choice. The pulp is processed to remove impurities and then fluffed to increase its absorbency. In sanitary napkins, wood pulp is often combined with other materials to enhance its performance.

### Superabsorbent Polymers (SAP)

Superabsorbent polymers are synthetic materials that can absorb and retain large amounts of liquid. They are typically made from sodium polyacrylate, a polymer that can absorb up to 300 times its weight in water. SAP is used in the core of sanitary napkins to lock in moisture and prevent leakage.

## Top Sheet Material

The top sheet is the layer of the sanitary napkin that comes into direct contact with the skin. It is designed to be soft, comfortable, and quick-drying. The most common materials used for the top sheet are non-woven fabrics and perforated films.

### Non-Woven Fabrics

Non-woven fabrics are made from synthetic fibers such as polypropylene or polyester. These fabrics are lightweight, breathable, and soft to the touch. They are also designed to wick moisture away from the skin, keeping the user dry and comfortable.

### Perforated Films

Perforated films are thin plastic sheets with tiny holes that allow liquid to pass through while keeping the surface dry. These films are often used in combination with non-woven fabrics to enhance the comfort and performance of the top sheet.

## Back Sheet Material

The back sheet is the outermost layer of the sanitary napkin, designed to prevent leakage and protect clothing. It is typically made from a waterproof material such as polyethylene or polypropylene.

### Polyethylene

Polyethylene is a common plastic material used in the back sheet of sanitary napkins. It is lightweight, flexible, and provides an effective barrier against moisture. Polyethylene back sheets are also breathable, allowing air to circulate and reducing the risk of irritation.

### Polypropylene

Polypropylene is another plastic material used in back sheets. It is known for its strength, durability, and resistance to moisture. Polypropylene back sheets are often used in high-performance sanitary napkins that require extra protection against leakage.

## Adhesive and Release Paper

To keep the sanitary napkin securely in place, an adhesive is applied to the back sheet. The adhesive is typically a pressure-sensitive adhesive that sticks to the underwear without leaving residue. A release paper covers the adhesive to protect it until the napkin is ready to be used.

### Pressure-Sensitive Adhesive

Pressure-sensitive adhesives are designed to stick to surfaces when pressure is applied. They are commonly used in sanitary napkins because they provide a secure hold without the need for additional fasteners. These adhesives are also gentle on fabrics and easy to remove.

### Release Paper

Release paper is a coated paper that protects the adhesive until the sanitary napkin is ready to be used. It is typically made from silicone-coated paper or film, which allows it to be easily peeled away without damaging the adhesive.

## Conclusion

The raw materials used in sanitary napkins are carefully selected to ensure comfort, safety, and effectiveness. From the absorbent core to the soft top sheet and leak-proof back sheet