| 主权项 |
1. A process for the manufacture of viscose comprising the steps of:
a) providing a non-dissolving pulp as a raw material; b) steeping the pulp in caustic solution; c) processing the steeped pulp; d) steeping the processed steeped pulp for a second time in caustic solution; and e) further processing the pulp from step d) to form a viscose solution; wherein the steeping conditions are selected such that: i) when the pulp comprises a Softwood Kraft pulp as at least the or a major component, the caustic concentration of the solution in step d) is at least about 11.5% w/w and the ratio of caustic concentration in the solution of step b) to that of the solution in step d) (the S1/S2 ratio) is from 1 to 1.8; ii) when the pulp comprises a Bleached Eucalyptus pulp as at least the or a major component, the caustic concentration of the solution in step d) is from 15% w/w to 20% w/w and the ratio of caustic concentration in the solution of step b) to that of the solution in step d) (the S1/S2 ratio) is from 0.1 to 5; and iii) when the pulp comprises a non-dissolving pulp other than a Softwood Kraft or Bleached Eucalyptus pulp as at least the or a major component, the caustic concentration of the solution in step d) is at least about 11.5% w/w and the ratio of caustic concentration in the solution of step b) to that of the solution in step d) (the S1/S2 ratio) is from 0.1 to 5. |
