A brief description of the high-frequency welding process and performance of multi-layer co-extruded TPU calendered film

Combining functional layer design and molecular-level fusion, this technology achieves optimal balance between material performance and processing efficiency. The resulting products offer superior abrasion resistance, weather stability, and environmental sustainability, serving as ideal replacements for conventional materials across medical, industrial, and consumer electronics applications.

I. Manufacturing Process

1. Material Selection & Coextrusion

• Material: Polyester-based TPU (heat/chemical resistance for industrial use) or polyether-based TPU (low-temperature/hydrolysis resistance for outdoor/humid environments).
• Coextrusion: Multiple extruders feed functionally distinct TPU melts into a single die, forming multilayer structures (e.g., wear-resistant outer layer, reinforcement mid-layer, sealing inner layer).
• Calendering: Melted TPU is pressed into continuous sheets via rollers, enabling high-volume production.

2. High-Frequency (HF) Welding

• Mechanism: Polarization friction from HF currents generates instant heat (up to melting point) for molecular-level bonding. Minimal heat-affected zones (HAZ) prevent deformation.
• Mold Design: Complex shapes (e.g., irregular pouches, 3D structures) achieved via custom molds, with pneumatic pressing ensuring uniform weld strength.

II. Performance Advantages

1. Exceptional Physical Properties

• Abrasion/Impact Resistance: High strength and elasticity for footwear, automotive interiors.
• Weather Stability: Retains flexibility in cold (-40°C) and resists softening in heat (85°C); no aging/cracking outdoors.
• Eco-Friendliness: Non-toxic combustion and biodegradability meet medical/food packaging standards.

2. HF Welding Superiority

• Sealing Integrity: Weld seam strength (≥95% parent material) and airtightness exceed adhesives, passing medical sterilization.
• Efficiency: 3–5× faster than hot-plate welding; energy-efficient and automation-ready.
• Design Flexibility: Supports multilayer coextrusion (transparent/matte) for complex 3D shapes or high-clarity windows.

III. Applications

1. Medical

• Biofluid Bags: Antistatic/antibacterial coextruded films for blood/dialysis bags with cryogenic transport reliability.
• Wound Dressings: Breathable, waterproof edges via HF-welded TPU-nonwoven composites.

2. Industrial & Outdoor

• Flexible Storage Tanks: Chemical-resistant, multilayer welded tanks with extended service life.
• Inflatable Toys: Non-toxic HF-welded floats for aquatic safety.

3. Consumer Electronics

• Phone Cases: Tri-proof HF-welded TPU cases with signal transparency.
• Wearables: Ultra-thin TPU-sensor composites for breathable smartwatch bands.