Sanitary Napkins Raw Material Composition and Properties

# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential hygiene products used by women worldwide. Understanding the raw materials used in their production is crucial for ensuring quality, comfort, and safety. This article delves into the composition and properties of the primary 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 core is typically made from a combination of the following materials:

– **Wood Pulp**: Wood pulp is a natural, biodegradable material that provides excellent absorbency. It is often used in its fluff form, which is lightweight and highly absorbent.
– **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 conjunction with wood pulp to enhance 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 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 allow for rapid liquid penetration.
– **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 transfer while preventing leakage.

## 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 commonly used for the back sheet include:

– **Polyethylene Films**: These are thin, flexible plastic films that provide an effective moisture barrier. They are also lightweight and durable.
– **Breathable Films**: Some sanitary napkins use breathable films that allow air to pass through while still preventing liquid leakage. This helps to reduce moisture buildup and improve comfort.

## 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 causing irritation. Common types of adhesives used include:

– **Hot Melt Adhesives**: These are thermoplastic adhesives that are applied in a molten state and solidify upon cooling. They provide strong adhesion and are commonly used in sanitary napkins.
– **Pressure-Sensitive Adhesives**: These adhesives form a bond when pressure is applied. They are often used in the wings of sanitary napkins to provide additional security.

## 5. Release Paper

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

## Properties of Sanitary Napkin Materials

The materials used in sanitary napkins must possess specific properties to ensure they perform effectively:

– **Absorbency**: The ability to absorb and retain liquid is crucial for the absorbent core and top sheet.
– **Softness**: The top sheet must be soft and comfortable to prevent irritation.
– **Breathability**: Materials should allow air to pass through to reduce moisture buildup and improve comfort.
– **Strength**: The back sheet and adhesives must be strong enough to prevent leakage and keep the napkin in place.
– **Biodegradability**: With increasing environmental concerns, there is a growing demand for biodegradable materials in sanitary napkins.

In conclusion, the raw materials used in sanitary napkins are carefully selected to ensure they provide the necessary comfort, protection, and performance. Understanding the composition and properties of these materials is essential for both manufacturers and consumers to make informed choices.