Cupro Manufacturing Process and Chemistry
topic
Cupro process: (1) purified cotton linters (99.5% α-cellulose) dissolved in Schweizer's reagent [Cu(NH₃)₄(OH)₂] at 5-20°C forming 6-8% solution (cuoxam), (2) ripening at 10-15°C for 12-24 hours, (3) stretch spinning through fine spinnerets (50-100 μm holes) into water or dilute acid bath (regeneration and copper-ammonia removal), (4) extensive washing, (5) copper recovery via electrolysis (>99% recovery), (6) finishing. Highly complex requiring closed systems.
Role
The challenging copper-ammonia chemistry and recovery requirements limit Cupro production to specialist manufacturers (primarily Asahi Kasei), but enable unique properties including finest denier capability (0.7-1.0 dtex) among regenerated celluloses.