What Is SMS Nonwoven Fabric?

SMS nonwoven fabric is a multi-layered composite nonwoven material, named after its layered structure: Spunbond-Meltblown-Spunbond. This material combines layers with different functionalities through a unique manufacturing process, offering high strength, high filtration efficiency, breathability, and lightweight properties. It is widely used in medical protection, hygiene products, and industrial applications.

                           SMS Nonwoven fabric

Structure and Material Composition of SMS Nonwoven Fabric

Outer Layer (Spunbond Layer)

The primary component is polypropylene (PP), with some variants using polyester (PET) or biodegradable materials (e.g., PLA). The process involves melting and extruding polymers to form continuous filaments, which are then stretched by high-speed airflow and bonded through thermal calendaring. This layer provides mechanical strength (tear resistance, abrasion resistance), surface smoothness, and softness.

Middle Layer (Meltblown Layer)

This layer consists of ultra-fine polypropylene fibers (1-5 microns in diameter), which are significantly finer than spunbond fibers. The process involves extruding molten polymer through spinnerets, where it is stretched by high-speed hot air into ultra-fine fibers that randomly form a dense mesh structure. This layer serves as the core protective barrier, achieving high-efficiency filtration (bacteria, particles, liquids) through physical blocking and electrostatic adsorption.

Composite Methods

One method is thermal bonding, where the three layers are pressed and heated by calender rollers, causing partial melting and bonding of the fibers. Another method is ultrasonic welding, which uses high-frequency vibrations to generate heat for bonding layers without an external heat source, making it suitable for thin materials.

Manufacturing Process of SMS Nonwoven Fabric

Spunbond Layer Production

First, polypropylene pellets are melted in a screw extruder (temperature: approximately 230-250°C). Next, the molten polymer is extruded through spinnerets to form fine streams, which are cooled and stretched into continuous filaments. Finally, the filaments are laid into a uniform web by a fiber distribution machine.

Meltblown Layer Production

First, the molten polymer is extruded through spinnerets and instantly stretched into micron-sized fibers by high-speed hot air (300-400°C) from both sides. These fibers are then randomly distributed on a collection device, forming a porous yet dense mesh structure.

Composite and Post-Processing

The spunbond, meltblown, and spunbond layers are sequentially stacked and bonded through thermal calendering or ultrasonic welding. Additives such as antibacterial agents (e.g., silver ions), antistatic agents, or hydrophobic coatings can be incorporated to enhance properties like waterproofing.

Applications

1. Medical Protection

Medical protective clothing: Uses SMS material with a basis weight of 40-50 g/m², compliant with the GB 19082-2009 standard, to prevent blood and bodily fluid penetration (e.g., used during Ebola and COVID-19 outbreaks).

Surgical masks: The middle meltblown layer provides a bacterial filtration efficiency (BFE) of ≥95%, while the outer spunbond layer offers moisture resistance.

2. Hygiene Products

Diaper backing: Uses SMS material with a basis weight of 10-20 g/m², combining breathability and leak-proof functions (e.g., brands like Pampers and Huggies).

Feminine hygiene products: Replaces traditional PE films to reduce heat buildup and improve comfort.

3. Industrial Applications

Dust-proof clothing: Used in electronics factories and cleanrooms to prevent human skin particles from contaminating precision instruments.

Oil filtration: Used in the automotive industry to adsorb lubricant mist (high-strength SMS with a basis weight of 80-100 g/m²).

Comparison of SMS Nonwoven Fabric with Other Materials

Market Status and Trends of SMS Nonwoven Fabric

Market Size: The global SMS nonwoven fabric market was valued at approximately $4.5 billion in 2023, with the medical sector accounting for over 60% (Source: Smithers Report).

Regional Distribution:China is the largest producer (40% of global capacity), followed by the U.S. and Europe.

Pandemic Impact: During COVID-19, demand for medical-grade SMS surged by 300%, leading to the rapid deployment of multiple high-speed production lines.