Sanitary Napkins Raw Material Composition and Properties

# 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 ensuring quality 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 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 made from sodium polyacrylate, which forms a gel-like substance when it comes into contact with liquid. This gel locks in moisture, preventing leakage and keeping the surface of the napkin dry.

## 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 polyethylene, 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 that is impermeable to liquids, ensuring that menstrual fluid does not seep through to clothing. The film is also breathable, allowing air to circulate and reducing the risk of skin irritation.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin to the underwear, ensuring it stays in place during use.

### Pressure-Sensitive Adhesive

Pressure-sensitive adhesives (PSAs) are typically used for this purpose. These adhesives are designed to stick firmly to fabric when pressure is applied but can be removed without leaving residue. They are usually made from synthetic rubber or acrylic compounds.

## 5. Release Paper

Release paper is a protective layer that covers the adhesive before the sanitary napkin is used.

### Silicone-Coated Paper

Silicone-coated paper is commonly used as release paper. The silicone coating prevents the adhesive from sticking to the paper, allowing it to be easily peeled off when the napkin is ready to be used.

## 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 appreciating the engineering and science behind everyday personal care products.