Sourcing Dissolving Pulp Feedstocks for Rayon Yarn Production
Dissolving pulp sourcing for rayon yarn relies on alpha cellulose purity specifications, alkali solubility controls, and commercial air dry tonnage audits.
Viscose Spinning Dope
Extrusion Solution
Dissolved sodium cellulose xanthate prepared in dilute aqueous sodium hydroxide forms the liquid fluid feed extruded into acid coagulating baths during regenerated fiber manufacturing. Viscose spinning dope possesses high viscosity and specific rheological properties necessary for uniform filament formation through micro-porous spinneret plates. Dissolving wood pulp undergoes alkalization, mercerization, xanthation and dissolution steps to yield this golden-yellow liquid compound.
Proper chemical stoichiometry governs dope stability and filtration characteristics prior to spinning.
Ripening Transformation
Holding the filtered xanthate solution in temperature-controlled tanks allows gradual chemical redistribution and de-xanthation before extrusion. During holding time, viscose spinning dope reaches an optimal salt figure index required for controlled coagulation in acid baths. Unripe dope resists proper coagulation, while over-ripe liquid precipitates prematurely inside delivery lines.
Temperature monitoring ensures precise ripening kinetics across production batches.
Dope Filtration
Multi-stage plate and candle filter networks extract undissolved gel particles and microscopic fiber fragments from liquid streams. Clean viscose spinning dope prevents spinneret hole blockage and reduces filament breakage rates during wet spinning operations.
Regeneration Bath
Metering pumps force filtered dope through submerged spinneret orifices into an acidic coagulation bath containing sulfuric acid, zinc sulfate, sodium sulfate and chemical modifiers. Acid neutralization regenerates solid cellulose filaments instantly as liquid streams exit nozzle jets.