Viscose Manufacturing Process
topic
The viscose process involves: (1) steeping cellulose in 18% NaOH at 20°C for 1-3 hours forming alkali cellulose, (2) ageing at 30°C for 40-50 hours to reduce DP from 1000 to 250-350, (3) xanthation with CS₂ forming cellulose xanthate (orange crumb), (4) dissolving in 5% NaOH creating viscous solution (500-1500 cP), (5) ripening for 4-5 days, (6) wet spinning through spinnerets (5,000-30,000 holes of 50-100 μm) into 10% H₂SO₄ bath with Na₂SO₄ and ZnSO₄.
Role
Understanding process parameters is critical for controlling fibre properties including tenacity (2.0-2.5 g/den dry, 1.0-1.3 wet), elongation (15-25%), and crystallinity (30-40%).