Thermal-Bonded Vs. Spunbond Nonwovens: The "Softness" And "Strength" In Hygiene Products
Behind every lightweight layer lies a technological balance of comfort and function.
In everyday hygiene products like diapers and Sanitary Napkins, two types of nonwoven materials play critical yet distinct roles:thermal-bonded (through-air) nonwovens and spunbond nonwovens. Though both belong to the nonwoven family, differences in their production processes grant them unique properties, making them indispensable in sanitary applications.
Thermal-bonded nonwovens act as the "gentle guardians" for skin contact, while spunbond nonwovens serve as the "structural backbone," working together to ensure comfort, dryness, and reliability.
01 Thermal-Bonded Nonwovens: The "Soft Touch" in Hygiene Products
Thermal-bonded nonwovens are produced by blowing hot air through a fiber web, melting the surface of low-melting-point fibers (e.g., ES fibers) to bond the structure without pressure. This "point-bonding" technique creates a fabric that is highly elastic and luxuriously soft.
In hygiene products, thermal-bonded materials excel as skin-facing layers due to their superior comfort and dryness:
- ✓ Sanitary napkin topsheets: Replacing traditional perforated films for better softness and reduced skin irritation.
- ✓ Diaper topsheets/ ADL layers: Rapid liquid penetration and dryness retention (weights range: 13–50 g/m²). Thinner variants (13–22 g/m²) suit pantyliners; midweight (20–30 g/m²) are ideal for wipes; heavier types (28–50 g/m²) enhance fluid distribution in diaper cores (SAP Sheet).
- ✓ Trends: Growing adoption in premium products, driven by demand for textured surfaces (embossed/perforated) for better aesthetics, dryness, and reduced reflux.
Key innovations include blends with functional fibers:
- ● Superabsorbent fibers (SAF): Boost liquid retention.
- ● Silk or chitosan fibers: Enhance smoothness, antibacterial properties, and skin-friendliness.
- ● ES fibers doped with nanosilver: Offer intrinsic antimicrobial protection.
02 Spunbond Nonwovens: The "Invisible Skeleton" for Structural Support
Spunbond nonwovens are made by extruding melted polymer (e.g., polypropylene) through spinnerets, stretching filaments via high-speed air, then laying and bonding them into a web. This yields fabrics with high tensile strength, dimensional stability, and cost efficiency.
In hygiene products, they provide critical structural reinforcement:
- ✓ Diaper backsheets: Composite with breathable films for leak-proofing.
- ✓ Sanitary Napkin Wings/cuffs: Shape retention and anti-sagging support.
- ✓ SAP Sheet: Envelop absorbent cores (e.g., fluff pulp/SAP) to prevent collapse.
A subtype, meltblown nonwovens, uses ultra-fine fibers for exceptional barrier/filtration properties—common in medical masks but also in premium hygiene liners.
03 Balancing Softness, Strength, and Sustainability
| Criteria | Thermal-Bonded Nonwovens | Spunbond Nonwovens |
|---|---|---|
| Primary Role | Skin comfort, liquid management | Structural integrity, encapsulation |
| Key Properties | Softness, loftiness, breathability | Strength, durability, cost efficiency |
| Eco-Advantage | Binder-free (thermal bonding only) | Recycle (PP-based) |
Future directions include:
- ● Sustainability: Biodegradable materials (e.g., PLA) growing at ~15% annually.
- ● Hybrid fabrics: Combining thermal-bonded softness with spunbond strength for ultrathin, high-performance products.
- ● Efficiency: Energy-saving thermal-bonding processes replacing older spunbond lines.
In hygiene design, thermal-bonded nonwovens deliver "gentle care," while spunbond provides "invisible support." Their synergy enables thinner, safer, and more sustainable products—proving that in the world of nonwovens, softness and strength are equally essential.