Recycled Nylon (ECONYL) and Closed-Loop PA6 Technology
topic
Recycled nylon PA6 (ECONYL, Aquafil, Arco, Italy) is produced by depolymerisation of post-consumer PA6 waste streams (discarded fishing nets, carpet face fibre, post-industrial PA6 waste) back to caprolactam monomer — then re-polymerised to virgin-equivalent PA6 polymer in a truly circular closed-loop chemical recycling process. ECONYL process (Aquafil, Arjan facility, Ljubljana, 100,000 tonnes/year PA6 depolymerisation capacity): PA6 waste collection (fishing nets from 10+ countries — Healthy Seas NGO collection programme, carpet waste from USA — Interface, Mohawk take-back) → contaminant removal (metal, PP, PE, other polymers) → hydrolysis depolymerisation (superheated steam 300°C, 15 bar, 3–4 hour residence time → PA6 → caprolactam + oligomers) → caprolactam purification (fractional distillation, activated carbon adsorption → 99.9% pure caprolactam) → re-polymerisation (VK tube identical to virgin PA6 process) → ECONYL nylon chip. ECONYL property comparison to virgin PA6: tenacity 6.8 versus 6.9 cN/tex (−1.4%), elongation 25% versus 25% (identical), colour (yellowness index YI +0.5 versus virgin — marginal difference allowing bright white dyeing), dyeability equivalent — virtually indistinguishable from virgin PA6 in all performance parameters. Carbon footprint: ECONYL 5.5 kg CO₂e/kg (versus virgin PA6 7.5 kg CO₂e/kg from caprolactam synthesis from cyclohexane → 27% reduction); further improvement if ECONYL electricity decarbonised to 100% renewable → projected 3.8 kg CO₂e/kg (49% reduction versus virgin). ECONYL brand adoption: Prada RE-Nylon (entire Ocean collection), adidas Parley (fishing net ocean plastic), Speedo Pure Valor, Girlfriend Collective — premium brand positioning with $1–3/unit sustainability price premium justified by GRS certified recycled content claim. PA6 carpet chemical recycling economics: Shaw Industries EcoWorx carpet tile take-back → ECONYL depolymerisation → 100% recycled PA6 carpet fibre → closed-loop product — demonstrates commercial viability of B2B industrial symbiosis circular economy model for PA6.
Role
ECONYL and closed-loop PA6 recycling demonstrates the most technically complete circular economy implementation in synthetic fibre — chemical depolymerisation back to caprolactam monomer producing virgin-equivalent quality without cumulative property degradation, overcoming the fundamental limitation of mechanical recycling, and the Aquafil-brand partnership model proving that collection logistics, processing economics, and premium pricing alignment can make nylon circular economy commercially self-sustaining at 100,000+ tonne annual scale.