PTFE (Polytetrafluoroethylene) coated fabrics are critical engineering materials used in heat shrink packaging lines, particularly in high-cycle environments where thermal, mechanical, and chemical resistance are essential. These materials serve two primary functions within the system:
- Thermal interface protection in L-Bar sealers
- High-temperature conveyor belting inside shrink tunnels
The design, construction, and surface properties of PTFE composites directly impact sealing integrity, system uptime, and film compatibility across a wide range of shrink packaging films such as polyolefin, PVC, and polyethylene.
PTFE Adhesive Fabrics
- Pressure-sensitive silicone adhesive backing
- Laminated to the sealing arm or wire housing
- Provides a continuous non-stick barrier
- Typical thickness: 0.08 mm to 0.13 mm
- Thermal range: –73°C to +260°C
PTFE Zone Tapes
- PTFE film with adhesive edges only (no adhesive under the heat wire zone)
- Eliminates adhesive flow at high temperatures
- Maintains optimal thermal transfer while preventing film adhesion
These PTFE materials thermally isolate the heating element from the packaging film, while still allowing efficient energy transmission for sealing. They also prevent residue accumulation, which is critical for maintaining clean seal lines and extending wire life.
2. Heat Shrink Tunnel Conveyors: High-Performance Belting Solutions
Shrink tunnels operate in the range of 120°C to 250°C, depending on the film type and throughput. Conveyor systems within these tunnels require belts that can endure:
- Constant radiant and convective heat
- Repetitive tension and tracking cycles
- Friction from product loading and unloading
- Non-stick requirements for films under tension
Two common conveyor configurations are used:
A. PTFE Coated Open-Mesh Belts
- Substrate: Woven fiberglass
- Coating: PTFE dispersion or film laminate
- Mesh sizes: 1×1 mm, 4×4 mm, etc. (airflow optimization)
- Joining method: Stainless-steel alligator/clipper splice
- Edge reinforcement: PTFE film or Kevlar stitching
- Application: Polyolefin and polyethylene shrink films
B. Silicone Coated Fiberglass Belts
- Higher friction coefficient than PTFE; better grip
- Lower thermal resistance than PTFE but sufficient for sub-260°C use
- Ideal for packages requiring gentle transport without slippage
PTFE belts are engineered with low surface energy (non-stick), dimensional stability, and resistance to thermal degradation, making them ideal for automated systems that demand minimal operator intervention and long maintenance intervals.
Engineering Advantages of PTFE-Coated Fabrics in Packaging Equipment
Property Performance Contribution
- Thermal Resistance up to 260°C Sustains continuous exposure in tunnels and sealers
- Low Coefficient of Friction (~0.05) Ensures smooth film release and transport
- Chemical Inertness Compatible with adhesives, films, and cleaning agents
- Dimensional Stability Maintains tension and tracking at high line speeds
- UV and Moisture Resistance Long service life in varied environments
- Easy Field Replacement (Clipper Joints) Reduces line downtime and labor cost
Conclusion
PTFE-coated composites are not just protective covers but engineered components that directly influence packaging efficiency, seal quality, and equipment longevity. Selecting the appropriate grade—based on temperature, film type, belt geometry, and joining method—is essential for achieving optimal throughput and minimal maintenance in industrial shrink packaging systems.
For technical datasheets, belt selection support, or OEM integration guidance, contact our engineering team（info@anligu.net).
