The merging or bonding of layers in nonwoven shopping bag production is typically achieved through various bonding methods. The choice of equipment depends on the bonding technique employed during the nonwoven fabric manufacturing process.

Here are common bonding methods and the corresponding equipment used for merging layers in nonwoven shopping bag production:

1. Thermal Bonding:
   • Equipment: Calendering machines or thermal bonding machines.
   • Process: In thermal bonding, heat is used to melt and fuse the fibers together. Calendering machines, which consist of heated rollers, can be used to achieve thermal bonding. The nonwoven fabric passes through the rollers, where heat and pressure facilitate the bonding of the fibers.
2. Ultrasonic Bonding:
   • Equipment: Ultrasonic bonding machines.
   • Process: Ultrasonic bonding involves using high-frequency ultrasonic vibrations to create localized heat, melting the fibers and bonding them together. Ultrasonic bonding machines have ultrasonic horns that apply pressure and heat to specific areas, resulting in the fusion of fibers.
3. Needle Punching:
   • Equipment: Needle punching machines.
   • Process: Needle punching involves entangling the fibers using barbed needles. The nonwoven fabric passes through the needle punching machine, nonwoven shopping bags where needles punch through the layers, intertwining the fibers and creating a cohesive structure.
4. Chemical Bonding:
   • Equipment: Chemical bonding machines or lines.
   • Process: Chemical bonding involves the application of adhesives or bonding agents to the nonwoven fabric. The fabric then goes through a curing or drying process to set the bonds. Chemical bonding machines or lines may include applicators for adhesive application and drying ovens.
5. Hydroentanglement (Water Jet Entanglement):
   • Equipment: Hydroentanglement machines.
   • Process: In hydroentanglement, high-pressure water jets are used to entangle and interlock the fibers. The nonwoven fabric passes through the machine, where water jets create a mechanical bonding effect. Hydroentanglement is effective in merging layers without the use of additional binders.
6. Spunbonding (Spunlaid Process):
   • Equipment: Spunbonding lines.
   • Process: In the spunlaid process, continuous filaments are extruded and laid onto a conveyor. Heat and pressure are applied to bond the filaments together. Spunbonding lines may include extruders, spinning systems, and calendering units.
7. Adhesive Lamination:
   • Equipment: Laminating machines.
   • Process: Adhesive lamination involves applying a layer of adhesive between two layers of nonwoven fabric. The layers are then pressed together using laminating machines. This method is effective for creating multi-layered nonwoven structures with specific characteristics.

The choice of bonding method and equipment depends on the desired properties of the nonwoven fabric and the specific requirements of the shopping bag. Manufacturers may use a combination of these methods to achieve the desired balance of strength, flexibility, and other performance characteristics in nonwoven shopping bags.