Polyamide (PA/Nylon)

Polyamide (PA), commonly known as nylon, is a key engineering plastic driving the move towards "replacing steel with plastic" in automotive lightweighting. If polypropylene (PP) is the "volume champion" dominating interior and exterior trims, polyamide (PA) is the "structural backbone" handling core functional loads. Thanks to its exceptional strength, heat resistance, and oil resistance, it is widely utilised in demanding core components across the engine bay, chassis, and electrical systems.

💪 Core Advantages: Why Is It the "Structural Backbone"?

The reason PA excels at replacing metal lies in its versatile and highly optimisable overall performance:

Excellent Mechanical Properties: PA inherently delivers high tensile strength, toughness, and outstanding wear resistance. Reinforced with glass fibre (GF), its strength and rigidity improve substantially. For instance, adding 30% glass fibre boosts PA's fatigue strength by up to 2.5 times compared to its unreinforced form.
Outstanding Heat and Chemical Resistance: PA reliably withstands high engine bay temperatures, engine oil, and various automotive fluids, which is why it thrives "under the bonnet".
Substantial Lightweighting Potential: PA has a significantly lower density than metal. Taking the intake manifold as an example, switching from metal to 30–35% glass fibre-reinforced PA6 delivers a component weight reduction of up to 50%, whilst trimming manufacturing costs by around 30%.

🚗 Two Mainstays and Core Applications

Within the broader PA family, PA6 and PA66 are the most widely used "twin pillars", accounting for over 90% of total PA usage in automotive manufacturing. They serve distinct, specialised roles across modern vehicles:

Main PA Grades	Key Characteristics	Typical Applications
PA6	Well-balanced overall performance and high cost efficiency; can meet high structural demands via reinforcement	Engine covers, intake manifolds, steering column modules, and dashboard cross beams (long glass fibre-reinforced)
PA66	Higher strength, rigidity, and thermal resistance than PA6, with superior dimensional stability	Automotive connectors, gears, radiator end tanks, airbags, and other precision, high-durability components
Long-chain PA (e.g. PA12, PA11)	Ultra-low moisture absorption, exceptional flexibility, oil resistance, and dimensional stability	Fuel lines, brake hoses, coolant lines, and various critical fluid piping systems

🔬 Technology Frontiers: Continuous Performance Breakthroughs

To meet the demands of new energy vehicles (NEVs) and smart mobility, PA materials continue to advance:

Low-Moisture-Absorption, High-Performance Materials: Addressing PA's tendency to absorb moisture, BASF developed the PA/PPA blend (Ultramid® T7000). Its rigidity and strength in both dry and conditioned states surpass PA66, alongside lower water absorption, making it an ideal metal replacement for structural parts exposed to moisture, such as wing mirror brackets and air brake components.
Active NVH Damping: High-frequency motor whine in electric vehicles places stricter demands on NVH (Noise, Vibration, and Harshness). Ascend engineered the Vydyne® AVS series high-damping polyamide, which absorbs vibrations and noise through inherent material properties. Used in engine and e-motor mounts, it significantly enhances cabin refinement whilst maintaining structural rigidity.
NEV-Dedicated Applications: In battery packs, halogen-free flame-retardant PA6 is utilised for battery enclosures; long glass fibre-reinforced PA6 is used for lightweight dashboard cross beams; and flame-retardant reinforced PA66/PA6 alloys, renowned for their superior electrical insulation and thermal resistance, have become the go-to solution for high-voltage connectors.