Sanitary towels are personal hygiene products designed to manage menstrual flow. Understanding their components helps individuals make informed choices. This article explores the materials used in sanitary towels, from their absorbent cores to outer layers and other functional elements.
Core Absorbent Materials
Sanitary towels rely on core absorbent materials to capture and retain liquid. Two main materials contribute to this absorption: wood pulp and superabsorbent polymers (SAPs). Wood pulp, often sourced from softwoods like pine, provides bulk and initial fluid distribution within the pad. It consists of cellulose fibers processed into a fluffy form, enhancing quick moisture absorption.
Superabsorbent polymers (SAPs), most commonly sodium polyacrylate, are an effective component for retaining large volumes of liquid. These polymers are found as small beads or granules that can absorb up to 300 to 1000 times their own weight in fluid. Upon contact with liquid, SAPs swell and transform into a gel-like substance, locking the fluid away and preventing leakage. This property allows sanitary pads to be thinner while maintaining high absorbency.
Outer Layers and Functional Components
Beyond the core, several other layers contribute to the functionality and comfort of sanitary towels. The top sheet, in direct contact with the skin, is engineered for comfort and to allow fluid to pass quickly into the absorbent core. Common materials include non-woven fabrics, often made from polypropylene or polyethylene, or sometimes organic cotton for a softer feel. Some top sheets are perforated polyethylene film for a dry sensation, though non-woven materials are popular for their soft, breathable qualities.
The back sheet forms the bottom, leak-proof barrier of the sanitary towel, made from polyethylene film. This plastic layer prevents absorbed fluid from leaking onto clothing, ensuring protection. An adhesive strip on the back sheet secures the pad to underwear, preventing shifting during use. This adhesive is a pressure-sensitive material, often protected by a peel-off release paper. Some pads also include “wings,” extensions that fold around the underwear for additional security and leak prevention.
Material Considerations
The materials used in sanitary towels raise various considerations for consumers, particularly regarding safety and environmental impact. Concerns exist regarding certain chemicals, such as volatile organic compounds (VOCs) and phthalates, which can be present in synthetic components and absorbed through the skin. Some manufacturers aim to use hypoallergenic materials and avoid fragrances or dyes to minimize the risk of skin irritation or allergic reactions.
The environmental footprint of disposable sanitary towels is a major concern due to the prevalence of plastic materials. Many conventional pads contain up to 90% plastic, which can take 500 to 800 years to decompose in landfills. This contributes to plastic waste and microplastic pollution. As a result, there is growing interest in alternative materials like organic cotton, bamboo fiber, and plant-based bioplastics for more eco-friendly options. These alternatives aim to offer similar performance while reducing environmental persistence.