Polyester staple fibers Meltblown Spunbond Process

The Meltblown-Spunbond process involves producing nonwoven fabrics from polyester staple fibers, which are widely used in filtration, medical applications, and hygiene products. Here’s an overview of the process:

1. Raw Material Preparation

Polyester Staple Fibers: These are short fibers typically less than 50 mm in length, created by cutting polyester filament.

Properties: The fibers are engineered for specific qualities, such as denier (fiber thickness), strength, and thermal bonding behavior, based on the end application.

2. Meltblown Process

The meltblown technique creates ultrafine fibers by extruding molten polymer through small nozzles and using high-speed hot air to stretch the fibers. The key steps include:

Polymer Melting: Polyester is melted in an extruder.

Extrusion: The molten polymer is extruded through a spinneret with fine orifices.

Fiber Formation: High-velocity hot air streams rapidly cool and elongate the extruded polymer into fine fibers.

Fiber Deposition: The ultrafine fibers are collected on a moving conveyor belt or drum, forming a web.

Fiber Size: Fibers produced are usually in the range of 2 to 5 microns in diameter.

Web Characteristics: The web is lightweight, has high porosity, and is suitable for filtration applications.

3. Spunbond Process

The spunbond method creates stronger, larger-diameter fibers and serves as the structural base layer for nonwoven composites. Steps include:

Polymer Melting and Extrusion: Similar to meltblown, polyester is melted and extruded through spinnerets.

Fiber Drawing: The fibers are cooled and drawn into continuous filaments using air or mechanical systems.

Web Formation: The drawn filaments are deposited onto a conveyor to form a web.

Bonding: The spunbond web is bonded (thermally, mechanically, or chemically) to provide strength and stability.

Fiber Size: Fibers typically range from 10 to 50 microns in diameter.

Web Characteristics: The spunbond layer is durable and has high tensile strength.

4. Combining Meltblown and Spunbond Layers

The meltblown and spunbond layers are often combined to create SMS (Spunbond-Meltblown-Spunbond) or SMMS structures. These composite fabrics combine the strength of spunbond with the fine filtration and barrier properties of meltblown layers.

Lamination or Bonding: The layers are bonded together using thermal, ultrasonic, or chemical bonding processes.

Applications: SMS or SMMS fabrics are used in surgical gowns, masks, and filtration products due to their excellent strength, breathability, and barrier properties.

5. Finishing Treatments

Hydrophobic or Hydrophilic Coatings: To alter moisture resistance.

Antimicrobial or Antistatic Additives: For enhanced functionality in medical or technical applications.

Coloration or Printing: Depending on product requirements.

Key Advantages

High productivity.

Versatility in fiber properties.

Combination of strength and fine filtration capabilities.