Torlon / PAI (Polyamide-imide)

PAI (polyamide-imide) is a melt-processable plastic that has exceptional physical and chemical properties. It performs well under severe stress conditions at continuous temperatures as high as 500° F. Torlon is an amorphous material with a Tg (glass transition temperature) of 537° F. Outstanding resistance to wear, creep and chemicals—including strong acids and most organics—make Torlon ideal for severe service environments. Torlon also has superior electrical and structural characteristics at high temperatures, excellent radiation resistance, an extremely low coefficient of linear thermal expansion, and exceptional dimensional stability. Torlon polyamide-imide (PAI) is a high strength plastic with the highest strength and stiffness of any thermoplastic up to 275°C (525°F). It has outstanding resistance to wear, creep, and chemicals – including strong acids and most organics – and is ideally suited for severe service environments.

Torlon  is a high performance amorphous (non-crystalline) engineering thermoplastic. Chemically, Torlon  is a polyamide-imide (PAI), a reaction product of trimellitic anhydride and aromatic diamines. It is called amide-imide because the polymer chain comprises amide linkages alternative with imide linkages. The combination of aromatic groups and imide linkages are responsible for the polymer's exceptional thermal stability. The amide groups impart flexibility and elongation, which results in an engineering plastic with exceptional toughness.

As Torlon PAI has a relatively high moisture absorption rate, parts used in high temperature service or made to tight tolerances should be kept dry prior to installation. Thermal shock resulting in deformation can occur if moisture laden parts are rapidly exposed to temperatures above 400°F (205°C).

Polyamide-imides may be thermosetting or thermoplastic amorphous polymers that have exceptional mechanical, thermal and chemical resistant properties. These properties put polyamide-imides at the top of the price and performance pyramid. Polyamide-imides are produced by Solvay Advanced Polymers under the trademark Torlon. Other high-performance polymers in this same realm are polyetheretherketones and polyimides. Polyamide-imides are used extensively as wire coatings in making magnet wire. They are easily made from isocyanates and TMA (trimellic acid-anhydride) in NMP.

Polyamide-imides hold, as the name suggests, a positive synergy of properties from both polyamides and polyimides, such as high strength, melt processibility, exceptional high heat capability, and broad chemical resistance. Polyamide-imide polymers can be processed into a wide variety of forms – from injection or compression molded parts and ingots – to coatings, films, fibers and adhesives. Generally these articles reach their maximum properties with a subsequent thermal cure process.

Key Features

Exceptional long-term strength and stiffness up to 275°C, Outstanding wear resistance, Superior toughness from cryogenic up to 275°C, Resistant to strong acids and most organics, Inherent flame resistance, Low CLTE.

Typical Applications

Aircraft hardware and fasteners, Mechanical and structural components, Transmission and powertrain components, Coatings, composites, additives, Electric motor components, Semiconductor fabrication and testing, Oil and gas exploration and recovery equipment, Bearing retainers, Gears, Bushings, Seals, Thrust washers.l

Key Properties

Maintains strength and stiffness to 500° F

Minimal expansion rate to 500° F

Excellent wear resistance in bearing grades

Withstands harsh thermal, chemical and stress conditions

Extruded or Injection-Molded Grades

Torlon 4203 (Electrical Grade)

Torlon 4203 has excellent compressive strength and the highest elongation of the Torlon grades. It provides electrical insulation and exceptional impact strength. This grade typically is used for electrical connectors and insulators because of its high dielectric strength. Torlon 4203 also is an exceptional choice for wear applications involving impact loading and abrasive wear. Torlon  4203 extruded PAI offers excellent compressive strength and the highest elongation of the Torlon  grades.

Applications

Connectors, switches, relays, thrust washers, spline liners, valve seats, check balls, poppets, mechanical linkages, bushings, wear rings, Insulators, cams, picker fingers, ball bearings, rollers, and thermal insulators.

Torlon 4301 (Bearing Grade) 

Torlon 4301 has the same basic physical and chemical properties as Torlon 4203 but is designed for use mainly for wear and friction parts. It offers a very low expansion rate, low coefficient of friction and causes little or no slip-stick in bearing applications. It has a flexural modulus of 1 million psi, a value higher than for most advanced engineering plastics. This grade does exceptionally well in service-wear applications such as non-lubricated bearings, seals, bearing cages and reciprocating compressor parts.

Torlon  4301 extruded PAI is primarily used for wear and friction parts. It offers a very low expansion rate, low coefficient of friction and exhibits little or no slip-stick in use. Torlon  4301's flexural modulus of 1,000,000 psi is higher than most other advanced engineering plastics. This grade excels in severe service wear applications such as non- lubricated bearings, seals, bearing cages and reciprocating compressor parts.

Applications

Bearings, thrust washers, wear pads, strips, piston rings, seals, vanes, and valve seats

Torlon 5530 (Glass-Reinforced Grade)

Torlon  5530 is 30% glass reinforced, compression molded PAI. It is ideal for higher load structural or electronic applications. This grade is similar in composition to Torlon  5030 PAI (injection molded). It is selected for larger shapes or when the greatest degree of dimensional control is required. Applications include burn-in sockets, gears, valve plates, impellers, rotors, terminal strips, and insulators. (see also Duratron T5530 PAI)

Extruded Grades.

Torlon 4XG

Torlon 4XG is a 30 percent glass-reinforced grade. Glass is added for improved load capacity. Torlon 4XG offers high rigidity and retention of stiffness. This grade is ideally suited for applications in the electrical/electronic, business equipment, aircraft and aerospace industries.

Torlon 4XCF

Torlon 4XCF is a 30 percent carbon-fiber reinforced grade. Carbon fibers are added for nonabrasive wear performance. Torlon 4XCF provides exceptional stiffness and nonabrasive wear performance and has the lowest coefficient of thermal expansion of the four Torlon grades.

  Technical Specifications

   Torlon / PAI (Polyamide-imide) Pictures