Spunbond vs Meltblown: Understanding the Differences

Key Differences at a Glance

Spunbond and meltblown are both nonwoven fabric technologies, but they serve fundamentally different purposes. Spunbond nonwoven is valued for its strength, durability, and cost-efficiency, making it the go-to choice for large-scale applications like hygiene products, agriculture, and medical gowns. Meltblown, on the other hand, produces ultra-fine fibers (as small as 1–5 microns) that excel at filtration — it is the critical middle layer in N95 respirators and surgical masks.

In short: spunbond = structure and coverage; meltblown = filtration and barrier. Most high-performance products (like SMS or SMMS fabrics) combine both technologies to leverage the strengths of each.

What Is Spunbond Nonwoven Fabric?

Spunbond nonwoven fabric is produced by extruding continuous thermoplastic filaments — typically polypropylene (PP) — and bonding them together thermally, chemically, or mechanically. The result is a fabric-like sheet that is lightweight yet strong, with excellent tear resistance and consistent pore structure.

How It's Made

The spunbond process involves four key stages:

1. Polymer chips (usually PP) are melted and extruded through a spinneret
2. Continuous filaments are drawn and attenuated by high-speed air
3. Filaments are laid randomly onto a moving conveyor belt
4. The web is bonded using heated rollers (thermal bonding) or needlepunching

This process allows manufacturers to produce fabrics ranging from 8 gsm to 200 gsm, covering an enormous variety of end-use requirements.

Key Properties of Spunbond

• High tensile strength and elongation
• Uniform fiber distribution and consistent basis weight
• Good liquid repellency when treated with hydrophobic finishes
• Breathable and lightweight
• Recyclable (PP-based grades)
• Easily customizable in color, texture, and treatment

What Is Meltblown Nonwoven Fabric?

Meltblown is a specialized nonwoven process where molten polymer is extruded through a die and immediately blown by high-velocity hot air, shattering the melt stream into extremely fine, randomly oriented microfibers. These microfibers self-bond as they cool, forming a dense, soft web.

Fiber diameters as fine as 0.5–5 microns give meltblown its extraordinary filtration capability — far beyond what spunbond can achieve alone. However, this fine structure also makes meltblown fragile, prone to tearing, and more expensive to produce.

Key Properties of Meltblown

• Ultra-fine fiber structure for superior particle capture
• High surface area — excellent for electrostatic filtration
• Very soft texture
• Low mechanical strength on its own
• Typically used as a functional core layer, not a standalone fabric

Manufacturing Process: Side-by-Side Comparison

Understanding how each fabric is made helps explain why their properties diverge so significantly.

Because meltblown requires a much higher melt flow index (MFI) resin and consumes more energy per unit weight produced, meltblown fabric typically costs 3–5× more than comparable spunbond on a per-kilogram basis.

Performance Differences That Matter in Real Applications

Filtration

Meltblown is unmatched for filtration. Its dense microfiber web — often electrostatically charged — can capture particles as small as 0.3 microns, which is why it forms the critical middle "M" layer in SMS (Spunbond-Meltblown-Spunbond) composite fabrics used in medical masks and respirators. A properly charged meltblown layer can achieve BFE (Bacterial Filtration Efficiency) of 98–99%+. Spunbond alone typically achieves 30–60% BFE at best.

Strength and Durability

Spunbond far outperforms meltblown in mechanical strength. A 30 gsm spunbond PP fabric will resist tearing and puncturing under normal handling, while a 30 gsm meltblown fabric of the same weight would be fragile and prone to deformation. This is why spunbond is used for the outer layers in composite products — it provides the structural integrity that meltblown cannot.

Softness and Drape

Meltblown's microfibers give it exceptional softness, almost cotton-like in feel at fine grades. Spunbond is softer than woven textiles but noticeably stiffer than meltblown. For skin-contact applications, finer spunbond grades (below 15 gsm) are engineered to improve tactile comfort.

Liquid Management

Both fabrics can be treated to be hydrophobic or hydrophilic. Spunbond is commonly used as the liquid-acquisition layer in diapers and feminine hygiene products due to its pore structure. Meltblown, with its denser fiber network, provides superior liquid barrier performance when treated correctly — though it is rarely used alone for this purpose.

Common Applications of Each Fabric

Where Spunbond Is Used

• Hygiene products: Topsheet and backsheet in diapers, adult incontinence pads, and sanitary napkins
• Medical textiles: Surgical gowns, drapes, sterilization wraps
• Agriculture: Crop covers, root barrier wraps, seedling protection
• Packaging: Reusable shopping bags, gift wrap, protective pouches
• Geotextiles: Soil separation, drainage, and erosion control
• Construction: Housewraps, roofing underlays

Where Meltblown Is Used

• Respiratory protection: N95 respirators, KN95 masks, surgical masks (filter layer)
• HVAC and industrial filtration: Air filters, vacuum filter bags
• Oil absorption: Spill cleanup pads and sorbents
• Liquid filtration: Water and chemical filtration cartridges
• Thermal and acoustic insulation: Specialty building materials

The Power of Combining Both: SMS and SMMS Fabrics

The nonwoven industry's most significant innovation was combining spunbond and meltblown layers into composite structures. The most common configurations are:

• SMS (Spunbond-Meltblown-Spunbond): Two spunbond outer layers sandwich a meltblown core. Delivers durability + filtration + softness. Weight range: 20–70 gsm.
• SMMS: Adds a second meltblown layer for higher barrier performance. Common in surgical gowns rated to AAMI Level 3 or 4.
• SMMMS: Three meltblown layers — used in the most demanding surgical and industrial PPE applications.

SMS fabric at 35–45 gsm is the standard specification for disposable surgical gowns used in operating theaters globally. The spunbond layers contribute approximately 60–70% of the composite weight, while the meltblown layer — despite being thin — provides the critical barrier function.

Choosing Between Spunbond and Meltblown: A Practical Guide

The decision should be based on your functional priorities:

For most hygiene and medical applications, an SMS or SMMS composite will outperform either fabric used alone, as it combines the mechanical integrity of spunbond with the barrier and filtration performance of meltblown.

Frequently Asked Questions

Q1: Is spunbond the same as spunlace?

No. Spunbond uses thermal or chemical bonding of continuous filaments. Spunlace (hydroentanglement) uses high-pressure water jets to mechanically entangle fibers, producing a softer, more textile-like fabric. They are distinct manufacturing processes with different end-use characteristics.

Q2: Can meltblown fabric be used alone without spunbond layers?

Technically yes, but rarely in practice. Meltblown on its own is fragile and prone to tearing. It is almost always laminated with spunbond layers (as in SMS) to achieve the mechanical durability needed for handling and use.

Q3: What does "gsm" mean in nonwoven fabrics?

GSM stands for grams per square meter — it is the standard unit for measuring the weight (basis weight) of nonwoven fabrics. Higher gsm generally means heavier, thicker fabric. Typical spunbond products range from 10 to 150 gsm depending on application.

Q4: Is polypropylene spunbond recyclable?

Yes. PP-based spunbond is a single-polymer material and is technically recyclable in facilities that accept polypropylene. However, composite fabrics like SMS may be harder to recycle due to mixed materials or chemical treatments.

Q5: What is the difference between spunmelt and spunbond?

"Spunmelt" is a broader industry term that encompasses both spunbond and meltblown technologies — essentially any nonwoven process where polymer is melted and extruded directly into fibers. Spunbond is one category of spunmelt, and SMS composites are the most commercially important spunmelt products.

Q6: How do I verify the filtration performance of a meltblown-based fabric?

Key test standards include BFE (Bacterial Filtration Efficiency) per ASTM F2101, PFE (Particulate Filtration Efficiency) per ASTM F2299, and pressure differential testing. For respirators, look for certifications such as NIOSH (N95), EN 149 (FFP2/FFP3), or GB 2626 (KN95).