Polyamide 66[4]

Updated: 2026-09-20

Overview

PA66, or Polyamide 66, is a semi-crystalline thermoplastic belonging to the nylon family. Developed by DuPont in the 1930s, it remains one of the most widely used engineering plastics due to its exceptional balance of mechanical properties and processability. Unlike other nylons, PA66 is formed through the polycondensation of hexamethylenediamine and adipic acid, resulting in a material with higher melting point and better thermal stability than PA6. This makes it particularly suitable for high-temperature applications.

Physical and Chemical Properties

PA66 exhibits excellent mechanical strength with a tensile strength of 80-90 MPa, making it stronger than many metals by weight. Its high crystallinity contributes to good dimensional stability and resistance to creep under load. The material maintains useful properties from -40°C to 100°C, with short-term exposure capability up to 180°C. It offers good resistance to hydrocarbons, oils, and many solvents, though it is susceptible to strong acids and oxidizing agents. Moisture absorption (up to 2.5% at equilibrium) affects mechanical properties and requires consideration in precision applications.

Main Applications

In automotive engineering, PA66 is extensively used for radiator end tanks, intake manifolds, and bearing cages due to its heat resistance and strength. The electrical industry employs it for circuit breakers, connectors, and coil formers where flame retardancy is required. Industrial applications include gears, bushings, and conveyor components where its wear resistance outperforms metals in many cases. Textile fibers made from PA66 are valued for their durability in carpets, ropes, and tire cords. Glass-filled variants (30-50% reinforcement) are common for structural components requiring enhanced stiffness.

Safety and Storage

While PA66 is generally considered safe when properly processed, decomposition products above 300°C may release hazardous fumes including carbon monoxide and nitrogen oxides. Adequate ventilation is essential during injection molding or extrusion operations. Storage requires protection from moisture absorption, which can affect processing and final properties. Original packaging should remain sealed until use, with recommended storage at temperatures below 40°C and relative humidity below 50%. Regrind material should be dried before reuse to maintain quality standards.

B2B Procurement Guide

When sourcing PA66, buyers should clearly specify required properties such as impact strength (notched Izod values), thermal stabilizer packages, and any regulatory compliance needs (e.g., FDA, UL94). Glass fiber content percentage significantly affects pricing and performance. Technical datasheets should be requested for melt flow index (MFI), moisture content, and additive packages. For large orders, consider requesting material certification and batch test reports. Lead times typically range from 2-6 weeks for standard grades, with specialty formulations requiring longer. Just-in-time delivery may be challenging due to the material's moisture sensitivity.