High-temperature plastics (typically referring to thermoplastics) are engineering plastics that can maintain their physical and chemical stability over long-term use at relatively high temperatures (usually above 150°C).
The following are mainstream high-temperature plastics, roughly listed in descending order of heat resistance and cost:
I. Top-Performance Grade (Long-Term Use Temperature > 200°C)
These materials are often referred to as “super engineering plastics.” They are expensive and primarily used in aerospace, military, and high-end industrial fields.
- PBI (Polybenzimidazole)
- Long-Term Heat Resistance: ~430°C
- Short-Term Peak: Up to 500°C
- Characteristics: Offers the highest commercial heat resistance among plastics, exceptional high-temperature stability, very low smoke and toxic gas emission, excellent mechanical strength, and wear resistance.
- Applications: Aerospace components, ultra-high vacuum environment parts, thermal protection systems.
- PEEK (Polyetheretherketone)
- Long-Term Heat Resistance: ~250°C
- Short-Term Peak: Up to 310°C
- Characteristics: Possesses outstanding overall properties: extremely high mechanical strength, wear resistance, hydrolysis resistance, chemical corrosion resistance, and flame retardancy. Maintains excellent mechanical properties even at high temperatures.
- Applications: Aerospace structural components, oil & gas valve seals, medical implants, high-performance gears, bearings.
- PI (Polyimide)
- Long-Term Heat Resistance: ~260°C
- Short-Term Peak: Above 300°C
- Characteristics: Excellent high and low-temperature performance, high insulation properties, low coefficient of thermal expansion, self-lubricating. Common forms include molded parts, films, and coatings.
- Applications: High-temperature insulating films (e.g., Kapton), aerospace gears and bearings, semiconductor industry components.
II. High-End Engineering Plastics (Long-Term Use Temperature 150°C – 200°C)
These materials are the most widely used in industrial and electronic fields, forming the backbone of high-temperature plastics.
- PPS (Polyphenylene Sulfide)
- Long-Term Heat Resistance: ~220°C
- Short-Term Peak: Up to 260°C
- Characteristics: Inherently flame retardant (UL94 V-0), excellent chemical corrosion resistance (known as the “king of plastics” in this regard), very good dimensional stability, high mechanical strength.
- Applications: Automotive engine peripheral components (sensors, pump bodies), electronic/electrical structural parts (bobbins, connectors), chemical piping and valves.
- PEI (Polyetherimide), Tradename: Ultem
- Long-Term Heat Resistance: ~170°C – 180°C
- Short-Term Peak: Above 200°C
- Characteristics: Offers performance similar to PEEK at a lower cost. High strength, high modulus, transparent, inherently flame retardant (UL94 V-0), and very low smoke and toxic gas emission.
- Applications: Medical sterilization trays, aerospace interior components, electronics (chip test sockets), food machinery parts.
- PPSU (Polyphenylsulfone)
- Long-Term Heat Resistance: ~180°C
- Short-Term Peak: Above 200°C
- Characteristics: Pale amber color, notably high toughness among high-temperature plastics, excellent hydrolysis and steam resistance, can withstand repeated steam sterilization.
- Applications: Medical instruments (surgical forceps, handles), aircraft interiors, food processing equipment, baby bottles.
- PSU (Polysulfone)
- Long-Term Heat Resistance: ~150°C – 160°C
- Short-Term Peak: Above 180°C
- Characteristics: Transparent, high strength, high rigidity, excellent electrical insulation properties, good hydrolysis and steam resistance.
- Applications: Medical devices, food processing equipment, electronic insulation parts, membrane separation materials.
III. Common Engineering Plastics (Long-Term Use Temperature ~150°C)
These materials offer a balance between cost and performance and are often used as metal substitutes in many applications.
- PPA (High-Temperature Nylon)
- Long-Term Heat Resistance: ~150°C – 185°C (varies by grade)
- Characteristics: By copolymerizing with aromatic monomers based on standard nylons (e.g., PA66), it significantly improves heat resistance and dimensional stability while retaining the good toughness and wear resistance of nylon.
- Applications: Automotive engine covers, turbocharger air intake pipes, electronic connectors.
- PTFE (Polytetrafluoroethylene), commonly known as “Teflon” or “Plastic King”
- Long-Term Heat Resistance: ~260°C
- Short-Term Peak: Up to 300°C
- Characteristics: Excellent chemical corrosion resistance, lowest coefficient of friction, superior non-stick properties, outstanding electrical insulation. However, it is a thermoplastic with relatively low mechanical strength and is typically not used for structural components.
- Applications: Seals, bearings, non-stick cookware coatings, chemical pipe linings.