# 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 combination of the following materials:

– Fluff Pulp: A highly absorbent material derived from wood pulp. It is soft, biodegradable, and capable of holding a significant amount of liquid.
– Superabsorbent Polymers (SAP): These are synthetic materials that can absorb and retain large amounts of liquid relative to their own mass. SAP enhances the absorbency of the core, preventing leakage.

## 2. Top Sheet

The top sheet is the layer that comes into direct contact with the skin. It is designed to be soft, comfortable, and quick-drying. Common materials used for the top sheet include:

– Nonwoven Fabrics: Made from synthetic fibers like polypropylene or polyethylene, nonwoven fabrics are lightweight, breathable, and provide a smooth surface.
– Perforated Film: Some sanitary napkins use a perforated plastic film as the top sheet, which allows liquid to pass through quickly while keeping the surface dry.

## 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 Film: A thin, flexible plastic film that is impermeable to liquids, ensuring that menstrual fluid does not seep through.
– Breathable Microporous Film: This material allows air to pass through while blocking liquids, enhancing comfort by reducing moisture buildup.

## 4. Adhesive

Adhesives are used to secure the sanitary napkin in place within 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 applied in a molten state and solidify upon cooling, providing a strong bond.
– Pressure-Sensitive Adhesives: These adhesives form a bond when pressure is applied, making them easy to use and reposition.

## 5. Release Paper

Release paper is a protective layer that covers the adhesive before use. It is typically made from silicone-coated paper or film, which allows it to be easily peeled away without leaving residue.

## Properties of Sanitary Napkin Materials

The materials used in sanitary napkins must possess specific properties to ensure effectiveness and comfort:

– Absorbency: High absorbency is crucial for preventing leakage and maintaining dryness.
– Softness: The materials should be soft to prevent irritation and provide comfort during use.
– Breathability: Breathable materials help reduce moisture buildup, minimizing the risk of skin irritation and odor.
– Biodegradability: With increasing environmental concerns, biodegradable materials are preferred to reduce the environmental impact of disposable sanitary napkins.

In conclusion, the composition and properties of the raw materials used in sanitary napkins play a vital role in their performance and user satisfaction. By understanding these materials, manufacturers can continue to innovate and improve the quality of menstrual hygiene products.