Smart sanitary napkin with intelligent moisture sensor and notification

Abstract

A biodegradable sanitary napkin made from a potato starch-based polymer, consisting of: a breathable upper leaf (201), an absorbent core (202) and a biodegradable barrier layer (203), the pad is fully biodegradable under composting conditions within 90 days.

Description

Technical field of expertise:

[0001] The present invention relates to the field of environmentally friendly sanitary napkins and intelligent menstrual hygiene monitoring systems. More specifically, the invention relates to the development of biodegradable sanitary napkins made from potato starch as an environmentally friendly alternative to plastic-based menstrual hygiene products, as well as to intelligent period underwear or a system with a moisture sensor for real-time monitoring and alarm-based menstrual flow management. The invention lies at the interface between biomedical engineering, sustainable materials science, wearable health technology, and smart textiles.

[0002] It addresses two major global concerns: the environmental impact of non-biodegradable menstrual products and the lack of intelligent tools for menstrual hygiene management. By combining biodegradable polymer technology and embedded sensor technology, the invention offers a practical, sustainable, and user-friendly menstrual hygiene solution that improves comfort, hygiene, convenience, and environmental responsibility. Background of the invention:

[0003] Menstrual hygiene management has long been an essential, yet often overlooked, aspect of women's health and well-being. Billions of sanitary pads are used worldwide each year, most of which are made from non-biodegradable plastics, synthetic fibers, and superabsorbent polymers that can take hundreds of years to decompose. These products contribute significantly to litter accumulation, soil pollution, and microplastic pollution, creating serious environmental hazards.

[0004] In India alone, it is estimated that over 12 billion single-use sanitary pads are discarded every year. Most of these contain polypropylene, polyethylene, and other petrochemical-based polymers, which not only persist in the environment but also release toxins when burned. The disposal problem is particularly acute in rural and semi-urban areas, where proper waste separation and recycling systems are minimal.

[0005] From a health perspective, conventional sanitary pads often lead to skin irritation, allergic reactions, and microbial growth, primarily due to their synthetic components and lack of breathability. Furthermore, the absence of real-time monitoring mechanisms to inform users of their saturation level can result in prolonged pad use, leakage, discomfort, and an increased risk of infections such as bacterial vaginosis or urinary tract infections.

[0006] While some biodegradable alternatives exist, many are based on bamboo, banana fibers, or cornstarch-based composites that are expensive or limited in absorbency. Additionally, the integration of smart wearable technology into menstrual products is still in its infancy. Current solutions often focus on mobile tracking applications but fail to incorporate direct sensory feedback mechanisms that can accurately indicate menstrual flow conditions.

[0007] Recognizing these challenges, the present invention introduces a two-component solution: 1. A biodegradable sanitary napkin made from potato starch-based polymers that ensures environmental compatibility without compromising absorbency or comfort. 2. An intelligent menstrual underwear system with an embedded moisture sensor that detects the saturation of the menstrual flow and communicates with a smartphone application for timely notifications.

[0008] By merging environmentally friendly materials science and digital health monitoring, this invention not only addresses ecological sustainability but also revolutionizes menstrual hygiene management through intelligent feedback systems that offer users real-time awareness and increased comfort. Summary of the invention:

[0009] The present invention introduces a comprehensive, sustainable, and intelligent menstrual hygiene solution that combines biodegradable materials with wearable sensor technology to improve both environmental compatibility and user hygiene. It focuses specifically on two integrated components: a biodegradable sanitary pad made from potato starch-based polymers, and a smart period underwear or system with moisture sensors capable of detecting saturation levels and transmitting real-time alerts via a mobile application. Together, these innovations constitute a next-generation approach to menstrual hygiene management that combines comfort, sustainability, and digital intelligence.

[0010] The biodegradable binding component of the invention replaces conventional plastic materials with an environmentally friendly and compostable biopolymer derived from potato starch. The binding's structure consists of a soft, non-woven, and breathable top layer for skin comfort; an absorbent core made of potato starch and plant cellulose fibers, offering high liquid absorption and rapid wicking; and a biodegradable, waterproof backing layer that prevents leakage while maintaining breathability. The starch-based material exhibits favorable biodegradability, decomposing completely within 90 days under composting conditions and leaving no toxic residues or microplastic fragments.Furthermore, the sanitary pad can optionally be enriched with natural antibacterial and pH-balancing agents such as neem or aloe vera extract to promote hygiene and prevent skin irritation or infection. This eco-friendly design offers a sustainable alternative to traditional sanitary pads, which can remain in the environment for hundreds of years.

[0011] In addition to the biodegradable pad, there is a smart menstrual monitoring system that brings digital intelligence to period care. The system includes a flexible, washable, and reusable sensor patch that is integrated into underwear or attached to the underside of the pad. This patch contains a moisture sensor that detects menstrual fluid levels through changes in electrical conductivity, a microcontroller for signal processing, a wireless communication unit such as Bluetooth or ZigBee for data transmission, and a rechargeable battery that powers the module. When the pad approaches saturation, the system automatically sends alerts to the user's smartphone via a dedicated app, prompting a timely pad change. The app also tracks menstrual cycles, predicts upcoming periods, and provides hygiene and health recommendations.The sensor calibration distinguishes between menstrual blood and sweat, minimizing false notifications and ensuring accuracy.

[0012] The invention offers several advantages: it significantly reduces environmental pollution from plastic waste, improves personal hygiene through timely monitoring, and increases user comfort and confidence by preventing leakage and discomfort. It also contributes to a growing global movement toward sustainable, technology-integrated health products. By combining biocompatible material science and sensor-based feedback mechanisms, this invention redefines menstrual hygiene management as an intelligent, environmentally conscious process. The synergy of these two components—eco-friendly materials and intelligent wearable sensors—creates a system that is safe, sustainable, and user-centric, offering an advanced, reliable, and environmentally conscious solution for menstrual hygiene management in the modern era. Brief description of the drawing Fig.shows a block diagram of the system according to the invention. Detailed description of the invention

[0013] The present invention describes a novel approach to menstrual hygiene management through the integration of biodegradable materials and intelligent sensor technologies. The system comprises two core elements: a biodegradable sanitary pad made from potato starch-based polymers and a smart menstrual monitoring unit designed to detect saturation with menstrual fluid and notify the user in real time via digital means. This combination addresses both the environmental and hygiene challenges associated with traditional menstrual products.

[0014] The biodegradable sanitary napkin is designed as a complete replacement for conventional plastic sanitary napkins, which contribute significantly to global waste. The key material innovation lies in the use of potato starch as the primary biopolymer. Starch granules are extracted from potatoes and transformed into a thermoplastic material through gelatinization and plasticization processes. Plasticizers such as glycerin or sorbitol are added to increase flexibility and durability while maintaining biodegradability. The resulting film is formed by extrusion or injection molding and serves as the structural basis for the napkin. The final product exhibits excellent tensile strength, absorbency, and breathability, ensuring comfort and functionality comparable to conventional synthetic sanitary napkins.

[0015] The sanitary pad consists of three main layers. The top layer is made of a soft, non-woven, breathable fabric that maintains skin comfort during extended wear. This layer may be treated with herbal extracts such as neem, turmeric, or aloe vera, which possess natural antibacterial and anti-inflammatory properties and help prevent rashes and infections. The central absorbent layer, or core, combines potato starch polymer and cellulose fibers, optimized for rapid fluid absorption and high retention. Upon contact with menstrual fluid, the starch molecules swell and trap the fluid in a gel-like matrix, preventing rewetting and ensuring dryness.The final barrier layer at the bottom consists of a waterproof yet biodegradable film made from modified potato starch polymer, preventing leakage while allowing air permeability for ventilation. The layers are laminated using heat bonding, eliminating the need for chemical adhesives and ensuring that each component remains biodegradable and compostable. Under suitable composting conditions, the entire napkin decomposes within 60 to 90 days, transforming into carbon dioxide, water, and organic matter without leaving behind any microplastics.

[0016] In addition to its material sustainability, the invention includes a technological component: the intelligent menstrual monitoring system. This component consists of a compact, flexible module that is either embedded in the lining of the underwear or attached to the underside of the sanitary pad. The module integrates a moisture sensor, a microcontroller unit (MCU), a wireless transmitter, a rechargeable power supply, and optionally a vibration alarm motor. The moisture sensor consists of conductive textile fibers or a thin-film polymer sensor that measures changes in electrical conductivity caused by moisture accumulation. Menstrual fluid, which is ionic in nature, alters the electrical properties of the sensor. The MCU processes these changes using a pre-calibrated algorithm to determine the saturation level of the sanitary pad.As soon as the saturation reaches a threshold level, the system triggers an alarm.

[0017] The wireless communication unit, typically a Bluetooth Low Energy or ZigBee module, transmits this data to a connected smartphone application. The application displays real-time status updates and notifies the user when it's time to change the pad. This proactive feedback prevents excessive moisture buildup, leakage, and the development of bacterial or fungal infections caused by prolonged pad use. The rechargeable lithium-polymer battery powers the entire module, and a power management circuit ensures efficient energy consumption. The module is designed to be ultra-thin, flexible, and washable, making it convenient for users and allowing for multiple reuse cycles.

[0018] The accompanying smartphone application serves as an interface between the user and the intelligent monitoring system. It records menstrual data, tracks cycles, predicts the onset of menstruation, and provides personalized hygiene recommendations. The system uses encrypted communication protocols to ensure user privacy and data protection. Furthermore, the app can be integrated with more comprehensive health monitoring systems, allowing users to track related parameters such as hormonal changes or stress levels, thus extending its usefulness beyond menstrual management. This makes the invention not just a sanitary solution, but a component of holistic women's health monitoring.

[0019] The calibration system of the intelligent module is a key aspect of the invention. It ensures that the moisture sensor accurately distinguishes between menstrual blood, sweat, or other forms of moisture that can occur during everyday activities. This is achieved through differential conductivity algorithms embedded in the MCU, which analyze multiple measurements over time before triggering a notification. This accuracy minimizes false alarms and ensures reliable performance even under varying environmental and physiological conditions.

[0020] From a manufacturing perspective, integrating biodegradable napkins with smart monitoring technology requires precise assembly. The biodegradable insert is first produced by mechanically laminating its three layers. Separately, the smart sensor module is fabricated on a flexible substrate using printed electronics techniques. Conductive silver paint or carbon nanotube-based inks can be used to create the sensor's conductive traces. The microcontroller (MCU) and wireless transmitter are surface-mounted on a miniature printed circuit board (PCB), encapsulated in a thin layer of medical-grade silicone for water resistance and flexibility. The sensor patch can then be attached to or embedded within the pad, depending on the design requirements.The modular nature of the system allows the electronic unit to be separated and reused, while the sanitary pad itself remains disposable and biodegradable.

[0021] The invention offers not only environmental and hygiene benefits but also introduces a new paradigm in the design of menstrual products. By combining sustainability with digital interactivity, it allows users to monitor their menstrual health in real time while reducing their environmental impact. The use of potato starch polymers decreases reliance on petroleum-based plastics, while the smart technology component bridges the gap between health awareness and comfort. This dual-benefit system aligns with global initiatives aimed at reducing plastic pollution and promoting smart wearable health solutions.

[0022] The invention can be further developed to integrate additional functions such as temperature sensing, odor detection, or automatic data synchronization with healthcare providers for medical monitoring. The modularity of the sensor system allows for easy integration with various types of menstrual products, including reusable cloth pads and period underwear. Furthermore, the large-scale production of the biodegradable pads can be achieved at relatively low cost, as potato starch is readily available and established biopolymer processing techniques exist.

[0023] In conclusion, the invention offers a novel and comprehensive solution to two major global challenges: environmental damage caused by non-biodegradable menstrual waste and the lack of intelligent tools for managing menstrual hygiene. The biodegradable sanitary pad ensures environmental responsibility, while the intelligent sensor system provides real-time feedback for improved health and comfort. Together, they redefine menstrual hygiene as a sustainable, technologically advanced, and user-friendly experience. This integrated, eco-friendly system represents a transformative innovation capable of reshaping menstrual hygiene management by combining the benefits of sustainability, safety, and digital empowerment in a single, holistic product. Reference symbol list 200 System 201 breathable topsheet 202 absorbent core 203 biodegradable barrier layer

Claims

[1] A biodegradable sanitary napkin made from a potato starch-based polymer, consisting of: a breathable upper leaf (201), an absorbent core (202) and a biodegradable barrier layer (203), the pad is fully biodegradable under composting conditions within 90 days. [2] The bandage according to claim 1, wherein the absorbent core is impregnated with natural antibacterial agents such as neem or turmeric extracts to prevent infections. [3] The pad according to claim 1, further equipped with a removable moisture sensor configured to detect menstrual flow saturation and sends warnings via a smartphone application. [4] The bandage according to claim 3, wherein the sensor module comprises a microcontroller, a wireless transmitter and a rechargeable power source for real-time communication. [5] The sanitary pad according to claim 3, wherein the sensor distinguishes menstrual fluid from sweat based on calibrated conductivity parameters. [6] The bandage according to claim 1, wherein the upper layer is treated with pH-balancing natural compounds to maintain skin health. [7] The sanitary pad according to claim 3, wherein the mobile application tracks menstrual cycles, predicts the start of the period and provides hygiene reminders. [8] The bandage according to claim 3, wherein the sensor unit is reusable and can be attached to different types of bandages. [9] The binder according to claim 1, wherein potato starch serves as the base polymer and ensures biodegradability and sustainability.

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