# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential personal 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.
– **Superabsorbent Polymers (SAP)**: SAPs are synthetic materials that can absorb and retain large amounts of liquid relative to their mass. They are often used in combination with wood pulp to improve the absorbency of the core.

## 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 for the top sheet include:

– **Nonwoven Fabrics**: These are made from synthetic fibers such as polypropylene or polyester. They are designed to be soft and breathable while allowing rapid liquid transfer to the absorbent core.
– **Perforated Films**: Some sanitary napkins use perforated plastic films as the top sheet. These films are designed to be soft and allow for quick liquid absorption.

## 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 provide an effective moisture barrier. They are often used in combination with other materials to enhance durability and comfort.
– **Nonwoven Fabrics**: Some sanitary napkins use nonwoven fabrics for the back sheet to provide a softer feel and better breathability.

## 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 skin irritation. 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 strong bonding and are commonly used in sanitary napkins.
– **Pressure-Sensitive Adhesives**: These adhesives form a bond when pressure is applied. They are often used for their ease of application and ability to adhere to various surfaces.

## 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**: This type of paper is treated with silicone to prevent the adhesive from sticking to it. It is easy to remove and ensures that the adhesive remains effective until the napkin is used.

## 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**: The ability to absorb and retain menstrual fluid is crucial. Materials like wood pulp and SAP are chosen for their high absorbency.
– **Softness**: The top sheet and back sheet must be soft to prevent skin irritation and provide comfort during use.
– **Breathability**: Good breathability helps to reduce moisture buildup and prevent discomfort.
– **Leakage Protection**: The back sheet and adhesive must provide effective leakage protection to ensure user confidence.
– **Biodegradability**: With increasing environmental concerns, there is a growing demand for biodegradable materials in sanitary napkins. Some manufacturers are exploring eco-friendly alternatives to traditional materials.

In conclusion, the composition and properties of the raw materials used in sanitary napkins play a vital role in determining the product’s performance and