What is polyamide 6?

The Industrial Truth and Survival Principles of Polyamide 6 (PA6)

1. Inherent Defects in the Molecular Chain

Monomer Trap: Ring-Opening Polymerization of Caprolactam → Contains cyclic oligomer impurities (up to 10%), which evaporate into bubbles during injection molding, resulting in "honeycomb lungs" on X-rays of gear parts.
Hydrogen Bond Weakness: Disordered amide group arrangement → Hydrogen bonds break upon water absorption, resulting in a 40% drop in strength (PA66 only loses 25%).

2. The Life and Death Line of Performance

3. Modification Scams

Glass Fiber Reinforcement Fraud: Unscrupulous factories use asbestos fibers as glass fiber → Thermal transition temperature is falsely labeled "70°C," filling the workshop with carcinogenic dust.
Flame Retardant Trap: Brominated flame-retardant PA6 releases toxic dioxin fumes when exposed to fire, leading to its EU ban for use in electronic housings (red phosphorus modification is used instead, doubling the cost).
Toughening Tricks: Adding recycled tire rubber powder → Short-term toughening, but after six months, the rubber powder ages and cracks due to aging.

4. A bloody battle in the application field

5. The deadly game of recycled materials

The three-reuse rule: First pass: 90% performance retention. Second pass: Impact strength halved. Third pass: Molecular chains break into slag → Gears break after 200 hours of operation
Toxicity upgrade: Flame retardants in recycled materials break down into polybrominated diphenyl ethers (strong carcinogens). A stroller manufacturer has been sued for $200 million.