# 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 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 blend of fluff pulp and superabsorbent polymers (SAP).

### Fluff Pulp

Fluff pulp is a highly absorbent material derived from wood fibers. It is lightweight, soft, and capable of holding a significant amount of liquid. The fibers are processed to create a fluffy, porous structure that enhances absorption.

### Superabsorbent Polymers (SAP)

SAP are synthetic materials that can absorb and retain large amounts of liquid relative to their own mass. They are often used in conjunction with fluff pulp to enhance the absorbency of the core. SAP can hold up to 30 times their weight in liquid, making them highly effective in managing menstrual flow.

## 2. Top Sheet

The top sheet is the layer that comes into direct contact with the skin. It is designed to be soft, comfortable, and quick-drying.

### Nonwoven Fabric

Nonwoven fabrics are commonly used for the top sheet due to their softness and breathability. These fabrics are made from synthetic fibers such as polypropylene or polyester, which are bonded together through mechanical, thermal, or chemical processes. Nonwoven fabrics are also hydrophobic, allowing menstrual fluid 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.

### Polyethylene Film

Polyethylene film is a common material used for the back sheet. It is a thin, flexible plastic that is impermeable to liquids, ensuring that menstrual fluid does not leak through. The film is also breathable, allowing air to circulate and reducing the risk of skin irritation.

## 4. Adhesive

Adhesive is used to secure the sanitary napkin in place within the underwear.

### Pressure-Sensitive Adhesive

Pressure-sensitive adhesive is applied to the back sheet to ensure the napkin stays in place during use. This type of adhesive is designed to stick firmly to fabric but can be easily removed without leaving residue.

## 5. Release Paper

Release paper is a protective layer that covers the adhesive before use.

### Silicone-Coated Paper

Silicone-coated paper is commonly used as release paper. It is coated with a thin layer of silicone that prevents the adhesive from sticking to it until the napkin is ready to be used. This ensures that the adhesive remains effective until the napkin is applied.

## Properties of Sanitary Napkin Materials

### Absorbency

The primary property of sanitary napkin materials is their ability to absorb and retain menstrual fluid. The combination of fluff pulp and SAP ensures high absorbency, while the nonwoven top sheet allows for quick fluid transfer.

### Comfort

Comfort is a key consideration in the design of sanitary napkins. The materials used, particularly the top sheet and back sheet, are chosen for their softness and breathability to minimize skin irritation and discomfort.

### Leakage Protection

Leakage protection is achieved through the use of impermeable back sheets and effective adhesive systems. These materials work together to keep the napkin securely in place and prevent any leakage.

### Hypoallergenic

Many sanitary napkin materials are hypoallergenic, meaning they are less likely to cause allergic reactions. This is particularly important for the top sheet, which comes into direct contact with sensitive skin.

### Environmental Considerations

With increasing awareness of environmental issues, many manufacturers are exploring eco-friendly materials for sanitary napkins. Biodegrad