There are various manufacturing processes for waterproof membranes, the core being balancing performance and cost according to the end application. Mainstream processes include cast lamination, spray lamination, hot-press lamination, co-extrusion lamination, coating lamination, and electrospinning.
Main Manufacturing Processes and Characteristics
Cast Lamination
Process: Plastic particles are hot-melted and then bonded together using an adhesive.
Characteristics: Poor air permeability, lower cost, commonly used in applications where air permeability requirements are not high.
Spray/Coated Lamination (Hot Melt Adhesive Lamination)
Process: Hot melt adhesive is applied to a film and then bonded to another material.
Characteristics: Low air permeability (adhesive easily clogs pores), poor temperature resistance (approximately 60℃), but the process is widely available and costs are controllable.
Hot-Pressure Lamination
Process: Pure physical hot-pressing technology without adhesive.
Characteristics: High air permeability, high temperature resistance (>110℃), good aging resistance; a high-end process meeting EU standards, but few manufacturers master this technology.
Co-extrusion Lamination
Process: Multiple layers of different materials are simultaneously extruded and laminated on a single machine.
Features: Capable of producing multi-layer composite films, combining the advantages of each layer, resulting in high process efficiency.
Coating Lamination
Process: Molten plastic particles are sprayed onto a substrate and allowed to cool and solidify.
Features: Relatively simple process, suitable for various substrates and film combinations.
Electrospinning
Process: A high-voltage electrostatic field is used to stretch a polymer solution or melt into nanofibers and deposit them into a film.
Features: Capable of preparing microporous membranes with high porosity and good pore connectivity; a cutting-edge technology in the field of waterproof and breathable membranes.