The temperature resistance of PTFE adhesive tapes is determined by multiple factors across four core dimensions: Material Composition, Structural Design, Manufacturing Process, and Operating Conditions. While the long-term service temperature typically peaks at 260°C (with short-term exposure reaching 280–300°C), actual performance depends on the following variables:

I. Material Composition: The Foundation of Thermal Resistance

1. Base Material Performance (The Decisive Factor)
   PTFE Molecular Structure: The C-F bond energy is as high as $485\,kJ/mol$. The fluorine atoms form a dense protective shield around the carbon skeleton, providing the fundamental basis for heat resistance. Purity and Modification:
   Pure PTFE: Long-term resistance at 260°C; short-term at 280°C.
   Cross-linked Modified PTFE: Can sustain 300°C continuously; at 350°C for 120 hours, weight loss is only 0.6%.
   Reinforced/Filled PTFE: Additives like fiberglass or graphite improve high-temperature creep resistance but may slightly lower the ultimate temperature limit of pure PTFE.
   Substrate Type:
   Pure PTFE Film: Operating range -200°C to 260°C. Flexible, but possesses lower mechanical strength at high temperatures.
   Fiberglass-Reinforced PTFE: Offers higher mechanical strength and superior dimensional stability at elevated temperatures.
2. Adhesive Layer Performance (The Critical Constraint)
   Adhesive Systems:
   Silicone Pressure-Sensitive Adhesive (PSA): Resists up to 250°C, maintaining 80% of its initial tack at peak temperature. This is the industry standard for high-temp tapes.
   Adhesive-free: Pure PTFE tape secured via mechanical fastening or wrapping; temperature resistance is identical to the PTFE base material (260°C+).
   Other Systems (e.g., Acrylic): Generally limited to below 180°C, significantly restricting the overall performance.
   Coating Uniformity: Influences bonding stability. Excessive thickness may lead to bubbling or delamination under high heat.

II. Structural Design: Impacting Thermal Stability and Durability

1. Composite Structure
   Three-layer Composite (Fiberglass + PTFE Coating + Silicone Adhesive): Balances strength and heat resistance; remains more stable under thermal stress. Single-layer PTFE Film: Prone to thermal creep; suitable for low-stress applications.
2. Thickness and Dimensional Stability

3. Reinforcing Materials
   Glass Fiber: Increases high-temperature creep resistance by 300% without altering the base temperature range of PTFE.
   Graphite/MoS2: Enhances lubrication and high-temperature stability.

III. Manufacturing Process: Determining Microstructure

1. Sintering Process
   Gradient Heating & Homogenization: Ensures a dense and uniform PTFE microporous structure, preventing C-F bond breakage caused by localized overheating.
   Sintering Temp & Duration: Directly affects crystallinity; higher crystallinity results in better heat resistance and mechanical strength.
2. Coating Technology
   Dipping vs. Spraying: Affects the adhesion and uniformity of the PTFE layer. Uniform coatings are less likely to peel under thermal expansion.
   Curing Temperature: The silicone adhesive must be fully cured; otherwise, it may soften or migrate (flow) at high temperatures.

IV. Operating Conditions: Performance Degradation Factors

1. Thermal Parameters
   Duration: Can withstand 300°C for short bursts (minutes), but long-term (thousands of hours) use should stay below 260°C.
   Thermal Cycling: Frequent cold-to-heat cycles accelerate material fatigue.
2. Mechanical Stress
   Pressure Influence: At 260°C, it is recommended to reduce working pressure to 60% of the room-temperature rating to avoid accelerated creep.
   Shear Force: High temperatures reduce the coefficient of friction, and high shear stress can lead to adhesive failure or tape delamination.
3. Chemical Environment
   Standard acids, alkalis, and organic solvents do not affect thermal limits.
   Exceptions: Molten alkali metals, elemental fluorine, and concentrated fluorosulfuric acid can destroy the PTFE structure at high temperatures.
4. Environmental Factors
   Oxygen Atmosphere: High-temp oxygen accelerates oxidative degradation, shortening service life.
   Vacuum: May cause trace outgassing at extreme temperatures.

V. Key Conclusions and Application Advice

The Bottleneck: The adhesive layer (Silicone max 250°C) is usually the weak link, rather than the PTFE substrate (260°C).
Comprehensive Assessment: Evaluation must integrate Temperature, Pressure, Media, and Time (TPMT); theoretical limits alone are insufficient.
Selection Advice:
For > 250°C: Prioritize adhesive-free pure PTFE or cross-linked modified products.
For High Pressure + High Temp: Use fiberglass-reinforced tape ($\ge 0.25\,mm$) and derate the pressure.
For Corrosive Environments: Ensure chemical compatibility; avoid contact with molten alkali metals or elemental fluorine.