What Is Hot Air Through Nonwoven Fabric?
Hot Air Through Nonwoven Fabric, also known as Through-Air Bonded Nonwoven (HAT Nonwoven), is a type of dry-laid nonwoven fabric produced by carding short fibers into a web and bonding them using hot air penetration.
Hot air passes through the fiber web, causing the low-melting components of the fibers to soften and bond at contact points, forming a stable yet bulky fabric structure.
Compared to hot-rolled nonwoven fabrics, HAT nonwoven fabrics do not rely on high-pressure compaction, thus maintaining higher bulkiness, softness, and breathability.
Key Raw Material: ES Bicomponent Fiber
ES Fiber Structure
ES fiber is a core–sheath bicomponent composite fiber, widely used in hot air through nonwoven production.
Typical structure:
-
Sheath layer: PE (Polyethylene) or low-melting PP
-
Core layer: PP (Polypropylene) or PET (Polyester)
Melting Point & Bonding Mechanism
-
PE (Polyethylene) melting point: 125–135°C
-
PP(Polypropylene) melting point: ~165°C
-
PET (Polyester) melting point: 230–260°C
When the oven temperature approaches the melting point of the sheath component, the sheath softens and partially melts, bonding adjacent fibers together.
The core component, with a higher melting point, maintains fiber shape and mechanical strength.
This structure results in nonwoven fabric with:
Point-like bonding (not block-like)
Larger fiber pores
Higher bulk and resilience
Fiber Fineness (Denier) Design
Hot air through nonwoven fabrics typically use fibers in the range of 0.8D–3.0D, depending on layer function.
-
Fine denier fibers (0.8–1.5D)
Used in top or bottom layers for softness and skin comfort. -
Coarse denier fibers (2.0–3.0D)
Used in acquisition and distribution layers (ADL) to improve liquid penetration and transfer.
This layered design is particularly common in disposable diapers, sanitary napkins, and adult incontinence products.
Fiber Finish/Oil Agent：Includes conventional spinning oils, dry-type finishes, and functional finishes.
Post-Processing Methods：Methods such as perforating (punching) and embossing are used to enhance the product’s visual effect and improve liquid permeability/strike-through capability.
Hot Air Through Nonwoven Production Process
1. Opening & Blending
Fibers are opened from compressed bales and uniformly blended according to preset ratios.
Key requirements include uniform mixing, full opening, and minimal fiber damage.
2. Carding & Web Forming
The blended fibers are separated into individual fibers and formed into a uniform web using a carding machine.
Carding quality directly affects fabric uniformity and appearance.
3. Hot-Air Through Bonding
-
The fiber web enters a flat-bed through-air bonding oven
-
Heated air penetrates the web vertically
-
The sheath component melts and bonds fibers at contact points
-
Hot air is collected, filtered, and recycled for energy efficiency
4. Cooling, Finishing & Winding
The bonded fabric passes through:
-
Surface smoothing or calendering
-
Cooling rollers for stabilization
-
Final winding into rolls
Optional post-processing includes perforating and embossing to improve liquid permeability and appearance.
Advantages of Hot Air Through Nonwoven Fabric
-
Excellent softness and bulkiness
-
High air permeability
-
Uniform thermal bonding
-
Low fiber damage
-
Ideal for hygiene and medical applications
Typical Applications of Hot Air Through Nonwoven Fabric
3. Other Applications
- Wiping wipes: Provides a soft wiping experience.
- Emergency protection: Used as a material for temporary protective equipment.
- Filter material: Used for air and liquid filtration, such as in air purifiers and industrial filters.
- Apparel and home textiles: Used as a base material for clothing and home textile products, providing a comfortable feel and good breathability.
Conclusion
As hygiene products continue to evolve toward higher comfort, softness, and breathability,
Hot Air Through Nonwoven Fabric has become an essential material due to its unique bonding structure and performance advantages.
For manufacturers, converters, and material buyers, understanding HAT nonwoven structure and process is key to material selection and product upgrading.