# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential personal care products designed to provide comfort and hygiene during menstruation. Understanding the raw materials used in their production is crucial for both manufacturers and consumers. 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 type of wood pulp that is highly absorbent and soft. It is derived from softwood trees like pine and spruce. The fibers are mechanically processed to create a fluffy, porous structure that can hold a significant amount of liquid.

### Superabsorbent Polymers (SAP)

SAPs are synthetic materials that can absorb and retain large amounts of liquid relative to their own mass. They are usually in the form of small granules or powders and are mixed with fluff 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 needs to be soft, non-irritating, and quick-drying.

### Nonwoven Fabric

Nonwoven fabrics are commonly used for the top sheet. These fabrics are made from synthetic fibers like polypropylene or polyester, which are bonded together through mechanical, thermal, or chemical processes. Nonwoven fabrics are chosen for their softness, breathability, and ability to wick moisture away from the skin.

## 3. Back Sheet

The back sheet is the outermost layer of the sanitary napkin, designed to prevent leakage and provide a barrier against external moisture.

### Polyethylene Film

Polyethylene film is a common material used for the back sheet. It is a lightweight, flexible, and waterproof plastic that effectively prevents menstrual fluid from leaking through. Some back sheets are also breathable, allowing air to circulate while still providing a moisture barrier.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin to the underwear. They need to be strong enough to hold the napkin in place but gentle enough to be easily removed without leaving residue.

### Pressure-Sensitive Adhesives

Pressure-sensitive adhesives (PSAs) are typically used for this purpose. These adhesives form a bond when pressure is applied, such as when the napkin is pressed onto the underwear. They are designed to be non-toxic and skin-friendly.

## 5. Release Paper

Release paper is a protective layer that covers the adhesive before use. It is peeled off to expose the adhesive when the napkin is ready to be used.

### Silicone-Coated Paper

Silicone-coated paper is commonly used for release paper. The silicone coating prevents the adhesive from sticking to the paper, making it easy to remove when needed.

## Conclusion

The raw materials used in sanitary napkins are carefully selected to ensure comfort, absorbency, and leak protection. From the absorbent core to the adhesive, each component plays a vital role in the overall performance of the product. Understanding these materials helps consumers make informed choices and manufacturers to innovate and improve their products.