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English Views: 0 Author: Judy Chen Publish Time: 2026-06-04 Origin: Site
Nonwoven fabrics are the structural backbone of modern disposable diapers, accounting for approximately 60–70% of total material composition by weight. These engineered fabrics determine the product's dryness, leak protection, skin comfort, and breathability.
This guide provides a systematic, layer-by-layer analysis of nonwoven applications in disposable baby and adult diapers. Drawing upon China GB standards (FZ/T 64112-2024, GB 15979-2024), EDANA/INDA NWSP test methods, ISO standards, and U.S. FDA material compliance requirements, we examine how material selection, manufacturing process, and quality specifications must align with each functional layer's unique demands.
China operates one of the world's most stringent regulatory frameworks for disposable hygiene products. Key standards include:
| Standard | Scope | Effective Date |
|---|---|---|
| GB 15979-2024 | Hygienic requirements for disposable sanitary products (microbial, chemical, toxicological safety) | July 1, 2025 |
| FZ/T 64112-2024 | Nonwovens for infant diapers (layer-specific material requirements) | January 1, 2025 |
| GB/T 30133-2022 | Topsheet nonwovens for disposable hygiene products (liquid management performance) | 2022 |
| GB/T 28004.1-2021 | Diapers—Part 1: Baby diapers (overall product performance) | 2021 |
Microbial limits: Total bacterial count ≤200 CFU/g; fungal count ≤100 CFU/g; pathogenic bacteria must not be detected. Chemical safety: pH 4.0–9.0; migratable fluorescent whitening agents prohibited; formaldehyde residues strictly limited.
The European nonwoven industry relies on harmonized test methods developed by EDANA (Europe) and INDA (North America), collectively published as NWSP (Nonwovens Standard Procedures):
| NWSP Method | Test Parameter | Relevance to Diapers |
|---|---|---|
| NWSP 70.3 | Liquid strike-through time | Topsheet acquisition speed |
| NWSP 70.7 | Repeated liquid strike-through | Multi-insult performance |
| NWSP 70.8 | Wetback after repeated strike-through | Skin dryness under load |
| NWSP 80.6 | Hydrostatic pressure resistance | Leg cuff / backsheet barrier |
| NWSP 130.1 | Basis weight (mass per unit area) | Material consistency control |
| NWSP 110.4 | Tensile strength (strip method) | Structural integrity |
| NWSP 402.0 | Softness (cup crush method) | Skin comfort assessment |
FDA 21 CFR 177.1520 establishes olefin polymers (including polypropylene) as acceptable for food-contact applications, a baseline material-safety reference widely cited by PP resin suppliers for hygiene applications.
ASTM D1117 (Standard Guide for Evaluating Nonwoven Fabrics) provides a framework for nonwoven testing, though specific test methods (e.g., D5035 for tensile properties, D5733 for trapezoid tear) are typically referenced individually. The D1117-99 edition has been superseded; users should consult ASTM International for current guidance.
ISO 11948-1:1996 (confirmed 2018) defines whole-product testing methods for urine-absorbing aids, commonly known as the Rothwell test. This standard measures total absorption capacity and is widely referenced by European manufacturers and international procurement organizations.
Polypropylene homopolymer and copolymer resins constitute the dominant feedstock for diaper nonwovens globally. Key material specifications:
| Property | Typical Range | Test Method |
|---|---|---|
| Melt Flow Index (MFI) | 25–40 g/10min (spunbond); 800–1200 (meltblown) | ASTM D1238 |
| Density | 0.90 g/cm³ | ASTM D1505 |
| Tensile strength at yield | 30–40 MPa | ASTM D638 |
Sheath-core bicomponent fibers (typically polyethylene sheath / polypropylene core, abbreviated as ES fiber) are the primary raw material for ATB (Air-Through Bonded) nonwovens. The PE sheath melts at 130–145°C, enabling thermal bonding without compromising the structural integrity of the PP core. This architecture produces the high-bulk, low-density webs characteristic of premium diaper topsheets and ADL materials.
The industry is progressing toward finer denier fibers to enhance surface softness and reduce skin friction. Current commercial offerings range from 1.3 dtex to 3.3 dtex for standard applications, with premium products exploring sub-1.0 dtex options.
| Process | Abbreviation | Key Characteristics | Primary Diaper Application |
|---|---|---|---|
| Air-Through Bonded | ATB | High bulk, extreme softness, excellent drape | Topsheet, ADL, waistband, backsheet |
| Spunbond | S / SS / SSS | High strength, uniformity, cost efficiency | Topsheet, core wrap, backsheet, landing zone |
| SMS / SMMS | Spunbond-Meltblown-Spunbond | Barrier + breathability combination | Leg cuffs, backsheet laminate, medical-grade wrap |
| Hydroentangled (Spunlace) | — | Fabric-like hand feel, high absorbency | Premium topsheet, sensitive-skin applications |
ATB technology utilizes heated air to bond bicomponent fiber webs, creating three-dimensional structures with superior loft and resilience. Key production parameters from leading equipment suppliers:
| Parameter | Specification |
|---|---|
| Basis weight range | 16–80 gsm |
| Topsheet typical | 20–30 gsm (100% bicomponent, 1.3–3.3 dtex) |
| ADL typical | 30–80 gsm (PP/PE or PET/CoPET blends, 1.3–6.6 dtex) |
| Line speed | Up to 250 m/min (ANDRITZ eXcelle range) |
| Annual capacity | Up to 12,000 t/a |
Our production lines utilize the ANDRITZ eXcelle ATB platform to deliver consistent 20–30 gsm topsheet materials with CV ≤±5% basis weight control, meeting FZ/T 64112-2024 and EDANA NWSP specifications for premium diaper brands across Asia and Europe.
ATB topsheets are favored in China and Japan, while Spunbond dominates in Europe and North America. This divergence reflects differing consumer preferences for bulk/softness versus strength/cost efficiency.
The topsheet is the first and most critical interface between the diaper and the user's skin. Its primary function is to rapidly transfer urine from the skin surface into the acquisition layer while maintaining a dry, comfortable feel.
Material Options:
| Performance Parameter | Typical Specification | Test Method |
|---|---|---|
| Basis weight | 18–25 gsm (ATB); 10–18 gsm (Spunbond) | NWSP 130.1 |
| Liquid strike-through (1st insult) | ≤3.0 seconds | NWSP 70.3 |
| Liquid strike-through (3rd insult) | ≤6.0 seconds | NWSP 70.7 |
| Rewet | ≤3.0 g | NWSP 70.8 / GB/T 30133 |
| Run-off | ≤5.0 g | GB/T 30133 |
| Dry tensile strength (MD) | ≥15 N/5cm | NWSP 110.4 |
| pH | 4.0–7.5 (GB/T 30133 topsheet specific); 4.0–9.0 (GB 15979-2024 general) | ISO 3071 |
| Formaldehyde | ≤6 mg/kg | ISO 14184-1 |
Technical focus: The ideal topsheet achieves "touch-and-go" fluid penetration—rapid acquisition without surface pooling or lateral spreading. Advanced designs incorporate 3D apertures or embossed patterns to minimize skin contact area and enhance air circulation.
The ADL receives fluid from the topsheet and distributes it laterally and longitudinally across the absorbent core. This prevents localized saturation, improves SAP utilization, and reduces the risk of leakage and rewet.
Core function: Convert "point loading" (concentrated urine stream) into "area absorption" (distributed across the core width), solving the localized saturation problem during heavy single-void events.
The core wrap encases the absorbent core (fluff pulp + superabsorbent polymer, SAP), preventing gel blocking, SAP loss, and core deformation during wetting.
| Failure Mode | Root Cause | Material Solution |
|---|---|---|
| Core breakage / clumping | Insufficient wet strength | High wet-strength ATB or SMS (≥20 gsm) |
| SAP dusting / leakage | Large pore structure, low basis weight | Dense Spunbond or SMS (≥22 gsm) |
| Gel blocking | Poor liquid permeability | Perforated or creped wrap design |
To address the core-breakage issue described above, our high wet-strength Spunbond SS core wrap grades are designed with enhanced fiber entanglement and hydrophilic finish compatibility, maintaining structural integrity even after SAP gel expansion and repeated fluid loading cycles.
Industry data indicates that approximately 80% of diaper core-breakage complaints can be traced to inadequate core wrap nonwoven selection—specifically insufficient wet tensile strength or improper pore structure.
Leg cuffs form a hydrophobic barrier around the thighs, preventing lateral leakage during movement, sleep, and position changes.
For leg cuff applications requiring reliable hydrophobic performance, our SMS/SMMS composite nonwovens are engineered with optimized meltblown fiber density to achieve ≥130 mmH₂O hydrostatic head resistance at 12–15 gsm, validated per NWSP 80.6 and available with custom elastic integration for high-speed diaper converting lines.
The back sheet is the outermost layer, preventing liquid escape while allowing water vapor transmission to reduce skin maceration and diaper dermatitis risk.
Construction: Nonwoven + microporous PE film laminate
| Performance Parameter | Specification | Test Method |
|---|---|---|
| Water vapor transmission rate (WVTR) | ≥1,500 g/m²/24h (minimum); premium >3,000 | ASTM E96 / ISO 15496 |
| Hydrostatic head resistance | ≥500 mm H₂O | NWSP 80.6 |
| MD tensile strength | ≥5 N/50mm | NWSP 110.4 |
Technological approaches:
Emerging trend: Full nonwoven breathable backsheets (no film) for enhanced recyclability and "plastic-free" marketing claims.
Elastic zones provide conforming fit and prevent gap-related leakage at the waist and legs.
The landing zone and fastening system must withstand repeated opening and closing without material failure.
| Defect | Symptom | Likely Cause |
|---|---|---|
| Slow penetration | Pooling on topsheet surface | Hydrophilic finish degradation; high surface tension |
| Increased rewet | Wet skin sensation | ADL saturation; insufficient core absorption rate |
| Side leakage | Fluid escaping leg cuffs | Cuff material hydrostatic head insufficient; elastic tension mismatch |
| Defect | Symptom | Likely Cause |
|---|---|---|
| Core wrap tearing | SAP gel exposed; clumping | Wet tensile strength <2.5 N/5cm under load |
| Layer delamination | Peeling between nonwoven and film | Inadequate hot-melt adhesive add-on or bonding temperature |
| Surface linting | Fiber debris on skin | Low fiber entanglement; excessive carding speed |
| Parameter | GB 15979-2024 Limit | Test Method |
|---|---|---|
| Total bacterial count | ≤200 CFU/g | GB 15979-2024 Annex |
| Fungal count | ≤100 CFU/g | GB 15979-2024 Annex |
| Pathogenic bacteria | Not detectable | GB 15979-2024 Annex |
| pH | 4.0–9.0 | ISO 3071 |
| Fluorescent whitening agents | Not detectable (migratable) | GB 15979-2024 |
| Formaldehyde | ≤6 mg/kg | ISO 14184-1 |
| Trend | Technology Path | Market Readiness |
|---|---|---|
| Fine denier fibers | <1.0 dtex ES fiber for enhanced softness | Commercial (pilot to scale-up) |
| Functional specialization | Directional fluid channeling; zonal hydrophilicity | Early commercial |
| Chemical-free finishing | Silicone-free, surfactant-free hydrophilic treatments | R&D to pilot |
| Lightweighting | Topsheet reduction from 25 gsm to 18 gsm while maintaining performance | Commercial |
| Mono-material design | All-PP diaper construction for recyclability | Pilot scale |
| Bio-based feedstock | Bio-PP from renewable sources (e.g., Braskem "I'm green") | Supply chain integration |
| Carbon footprint reduction | Low-energy ATB ovens; renewable energy in production | Industry-wide adoption |
| Criterion | Benchmark | Verification Method |
|---|---|---|
| Production line speed | ≥300 m/min (Spunbond); ≥200 m/min (ATB) | Equipment list, production records |
| Basis weight CV | ≤±5% (premium); ≤±10% (standard) | Statistical process control data |
| Online inspection | Metal detection, basis weight profiling, defect imaging | Facility audit |
| Fiber traceability | Batch-to-roll tracking | Quality management system review |
Beyond material specifications, we provide batch-to-roll traceability documentation, third-party test reports (SGS/Intertek), and dedicated technical support for line trials. For sample testing, diaper and sanitary napkin manufacturing materials, or custom material development, please contact our application engineering team.
Nonwoven material selection is not a commodity decision—it is a product performance determinant. From the skin-facing topsheet to the outer backsheet, each functional layer demands precise matching of fiber type, manufacturing process, basis weight, and finish chemistry to its specific role.
Layer-specific matching principles:
Compliance is market-specific: GB standards govern the China domestic market; EDANA/REACH frameworks apply to Europe; FDA 21 CFR and state-level requirements (e.g., California Proposition 65) apply to the U.S. Manufacturers serving multiple markets must maintain parallel testing and documentation systems.
Future competitiveness will be defined by three vectors: finer denier fibers for enhanced skin comfort, functional specialization (zonal properties, directional wicking) for performance differentiation, and sustainable material systems (bio-based feedstocks, recyclable mono-material designs) for regulatory and consumer alignment.
| Parameter | China GB | EDANA/INDA NWSP | ISO | ASTM |
|---|---|---|---|---|
| Basis weight | GB/T 24218.1 | NWSP 130.1 | ISO 9073-1 | D3776 |
| Liquid strike-through | GB/T 24218.8 | NWSP 70.3 | ISO 9073-13 | — |
| Wetback / Rewet | GB/T 24218.14 | NWSP 70.8 | — | — |
| Tensile strength | GB/T 24218.3 | NWSP 110.4 | ISO 9073-3 | D5035 |
| Hydrostatic head | GB/T 24218.16 | NWSP 80.6 | ISO 811 | D751 |
| Softness | — | NWSP 402.0 | — | — |
| Whole product absorbency | — | NWSP 354.0 | ISO 11948-1 | — |
| Term | Definition |
|---|---|
| ATB | Air-Through Bonded nonwoven; thermal bonding using heated air |
| ADL | Acquisition & Distribution Layer |
| ES Fiber | Bicomponent fiber with polyethylene sheath and polypropylene core |
| SMS | Spunbond-Meltblown-Spunbond composite nonwoven |
| SMMS | Spunbond-Meltblown-Meltblown-Spunbond composite |
| SAP | Superabsorbent Polymer (sodium polyacrylate) |
| WVTR | Water Vapor Transmission Rate |
| NWSP | Nonwovens Standard Procedures (EDANA/INDA harmonized methods) |
This technical guide is based on publicly available standards, industry publications, and equipment manufacturer specifications. Specific product requirements should always be validated against the latest revision of applicable standards and customer specifications. For procurement inquiries or technical consultations, contact us.
