# Sanitary Napkins Raw Material Composition and Properties

Sanitary napkins are essential hygiene products used by women worldwide. Understanding the raw materials that go into 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 and retaining 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, absorbent material.

### Superabsorbent Polymers (SAP)

SAPs are synthetic materials that can absorb and retain large amounts of liquid relative to their mass. They are usually in the form of small granules that swell upon contact with moisture, turning into a gel-like substance.

## 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 thin, flexible plastic film that is impermeable to liquids, ensuring that menstrual fluid does not leak through. It also provides a degree of flexibility and comfort.

## 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 are typically used in sanitary napkins. These adhesives are designed to stick firmly when pressure is applied but can be peeled off without damaging the fabric of the underwear.

## 5. Release Paper

Release paper is used to protect the adhesive before the sanitary napkin is used. It is usually made from silicone-coated paper or film.

### Silicone-Coated Paper

Silicone-coated paper is treated with a thin layer of silicone, which allows the release paper to be easily peeled away from the adhesive without leaving any residue.

## 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 in making informed choices and appreciating the technology behind everyday hygiene products.