Membrane Technology Hidden in Sanitary Pads and Incontinence Pads: The Key to Comfort and Safety

Preface 

Sanitary pads and incontinence pads (including adult diapers and baby diapers) are essential personal care products, and the realization of their core functions relies heavily on various membrane materials. From leak-proof and water-retention capabilities to breathability and skin-friendliness, as well as hygiene protection and environmental sustainability, iterative advancements in membrane material technologies directly determine the enhancement of product experience. 

For professionals in the membrane industry, the application of membrane materials in the personal care sector represents a highly promising niche market. For ordinary consumers, understanding these... “ Invisible ” The role of membrane materials enables a more scientific selection of products. This article will break down the core types of membrane materials, key performance requirements, purchasing considerations, and industry-wide green trends, helping you gain a deeper understanding of this specialized field of membrane technology. 

I. Classification of Core Membrane Materials: In Sanitary Pads and Urine Pads “ Membrane component ”

The membrane materials used in sanitary pads and diaper liners are primarily distributed across several key areas: the bottom layer for leak prevention, the top layer for fluid distribution, the intermediate layer for isolation, and the packaging. Different membrane materials serve distinct functions in these various locations, and their selection and process design each have specific priorities. 

(1) The core underlying membrane: leak-proof and breathable “ Guardian Barrier ”

The underlying membrane serves as the first line of defense against leaks and must also balance breathability to ensure comfort. It is primarily divided into three categories: 

• PE Breathable membrane : Widely used, it features micron-level breathable pores formed through a special process, enabling... “ Waterproof and breathable ” Water vapor transmission rate ( WVTR ) Need ≥1000 g/(m²·24h) High-end products can break through. 1500 g/(m²·24h) The embossing process is categorized into coarse patterns and fine patterns, offering both anti-slip performance and a soft tactile feel. 
• PE Cast film Primarily used for mid-to-low-end products, these materials offer good flexibility and barrier properties. Some products enhance their texture through processes such as spot printing; however, they have poor breathability and tend to become stuffy with prolonged use. 
• Composite membrane Made by combining a breathable membrane with nonwoven fabric, this material offers both skin-friendly properties and leak-proof performance, making it ideal for the base layer of high-end products. The composite manufacturing process enhances tensile strength and stability, making it well-suited for high-speed production. 

(2) Surface-associated membrane: guiding and isolating “ Auxiliary Expert ”

The surface membrane material provides flow guidance and isolation, ensuring absorption efficiency. 

• Isolation membrane / Release film Used on the adhesive area of sanitary pads to prevent sticking. Commonly used. UV Light-curing process; materials are optional. PE 、 PET Requires stable release force ( 2g-30g )、Curing rate ≥90% Complies with environmental protection and safety standards. 
• Flow-guiding membrane High-end products feature an additional layer between the surface and the core, with a textured design that accelerates liquid diffusion and enhances uniform absorption. The materials are mostly modified. PE The membrane must possess good permeability and tear resistance. 

(3) Functional Membranes: Precisely Tailored to Meet Special Needs 

Consumption upgrading is driving the application of functional membrane materials and has become the core of product differentiation. 

• Urine membrane Breathable membranes with color-changing ink added to baby diapers and adult incontinence pads change color upon contact with urine, signaling the need for replacement. It is essential to ensure high sensitivity, breathability, and safety. 
• Antibacterial film Add antibacterial ingredients such as silver ions to inhibit the growth of harmful bacteria. National standards require a bacteriostatic rate. ≥99% Ensure that the ingredients do not migrate and do not irritate the skin. 
• Biodegradable film : With PLA 、 PHA Made from bio-based materials, these substances are naturally biodegradable, helping to reduce white pollution and representing a key direction for green transformation. 

(4) Packaging film: for hygienic protection “ The last line of defense ”

Both the individual packaging and outer carton packaging for sanitary pads and incontinence pads require film materials, with the core requirements being barrier properties, sealing performance, and hygienic safety. 

• Individually packaged, mostly uses PE/PET Composite film, which must be moisture- and bacteria-resistant, suitable for high-speed heat sealing, and featuring strong heat-sealing strength. ≥2.0N 。
• Commonly used outer packaging BOPP or BOPP/PE Composite film requiring high tensile strength and puncture resistance to ensure transportation safety. 

II. Key Performance Indicators: The Core Dimensions for Assessing the Quality of Membrane Materials 

The performance of membrane materials directly determines the user experience and safety. Both membrane manufacturers and consumers need to pay close attention to key indicators when selecting products. 

(1) Basic Physical Properties 

• Thickness and Deviation Affects softness and barrier properties; the national standard has clear requirements (e.g., nominal thickness <). 10 μm Time deviation ±2 μm Inside. Too thick reduces comfort, while too thin easily leads to leakage. 
• Tensile strength : Vertical > 5.0N , horizontal > 3.0N Ensure that the material is not easily torn during processing and use, and that the underlying film can withstand everyday tensile stresses. 
• Appearance quality The membrane surface has no wrinkles or holes, with a diameter > 1mm Defects are not allowed to exist. ≤1mm Defect ≤5 one /0.1 m² Avoid leakage. 

(2) Core Functional Performance 

• Breathability : The core indicator is WVTR , national standard requirement > 1000 g/(m²·24h) , high-quality products > 1500 g/(m²·24h) Insufficient breathability can easily lead to stuffiness and skin damage. 
• Leak-proof Hydrostatic pressure ≥500 mmH₂O The underlying membrane must undergo a leakage test under simulated conditions to ensure it remains impermeable under normal use. 
• Hygiene and safety : No transferable fluorescent whitening agents detected; heavy metals < 0.1mg/kg , formaldehyde < 20mg/kg , microbial indicators meet the requirements. GB 15979-2024 New national standard. 

(3) Processing and Adaptation Performance 

For hygiene product companies, the compatibility of membrane materials with processing is crucial: 

• Wetting tension ： ≥36 mN/m Ensure printing and coating stability, and prevent ink shedding and uneven coatings. 
• Coiling quality End-face misalignment ≤3mm No pits or blisters, with one joint per roll. ≤2 Individual and single segment length ≥500 Rice ensures continuous and stable high-speed production. 

III. Purchasing and Application Guide: Practical Recommendations from a Membrane Material Perspective 

(1) Consumer Purchasing: Avoid Pitfalls from the Perspective of Membrane Materials 

• Prioritize breathable membrane products. : Select annotation “ Breathable base film WVTR > 1000 g/(m²·24h) products that avoid purely plastic base films without breathability markings to reduce stuffiness. 
• Pay attention to security certification. : Select annotation “ Compliant GB 15979-2024 No optical brighteners ” For such products, sensitive skin should avoid membrane products containing fragrances and colorants. 
• Select functional membrane materials on demand. Infants have priority for urinary catheterization; for individuals who are bedridden long-term, choose an antibacterial catheter. + High-permeability membrane urine pads reduce the risk of pressure ulcers and infections. 

(2) Membrane manufacturer production: Adapting to the core requirements of the hygiene products industry 

• Strictly control the quality of raw materials. : Medical-grade selection PE 、 PLA Use only virgin raw materials and strictly prohibit the use of recycled materials to ensure that no harmful substances are detected. 
• Optimize process parameters Precisely control the perforation process of the breathable membrane to ensure both breathability and strength. Use environmentally friendly inks for the printed film to guarantee clarity and adhesion. 
• Follow up on standard upgrades Follow GB 15979-2024 And establish standards for biodegradable materials, proactively planning R&D for environmentally friendly film materials. 

IV. Industry Trends: Innovation Directions for Membrane Materials Under the Green Transition 

The tightening of environmental policies and the upgrading of consumption are driving the membrane materials industry toward green, functional, and intelligent transformation. The key trends are as follows: 

(1) Increased Permeability of Biodegradable Membrane Materials 

“ Dual Carbon ” Under the target, the proportion of biodegradable film materials used will increase. 2024 Annual application rate reaches 38.9% , expected 2030 Year-over-year 60%。PLA/PHA Composite breathable membranes and the like have become a hot research and development topic, and membrane manufacturers need to break through cost and processing bottlenecks to achieve large-scale production. 

(2) The recycling system is gradually being improved. 

Traditional membrane materials have insufficient recycling rates. 1% Industry Exploration “ Design - Recycling - Regeneration ” Closed loop. Like Belgium. Whoosh United Ontex Introducing fully recyclable diapers; Japan’s Unicharm uses ozone for sterilization. + Acid treatment technology separates the membrane material from the core, and the recycled plastic meets food-grade standards. 

(3) Functional Integration and Technological Upgrading 

Future membrane materials will achieve “ Single function ” towards “ Multifunctional integration ” Breakthroughs include composite membrane materials that integrate breathability, antibacterial properties, urine detection capabilities, and biodegradability—all in one—along with smart monitoring membranes. Technologies such as ultra-fine denier fiber composites and nano-modification will enhance softness and stability. 

(4) Intelligent manufacturing drives quality improvement. 

Membrane company introduction MES The system implements digital control, enabling real-time monitoring of membrane material parameters through online detection, as well as comprehensive equipment efficiency. OEE ) Upgrade to 86% The above measures effectively reduce the defect rate and ensure consistent performance. 

Conclusion 

The film materials used in sanitary pads and diaper liners are the core carriers of comfort, safety, and functionality—from the very foundation. PE From breathable membranes to high-end biodegradable antimicrobial membranes, breakthroughs in membrane technology are driving the upgrade of the personal care industry. 

For the membrane industry, the hygiene and personal care sector represents a promising niche market that requires balancing innovation with compliance. For consumers, gaining an understanding of membrane materials can help them make scientifically informed product choices. In the future, membrane technology will make hygiene and personal care products more comfortable, safer, and more sustainable.