Treated Kraft pulp compositions and methods of making the same
Compositions including treated Kraft pulp, useful for making rayon fibers, having a lower degree of polymerization, a high R18, a low hemicellulose content, and high reactivity, are described. Methods of making the compositions are also described.
1. A treated Kraft pulp, comprising:
a hemicellulose content of 5% or more; a R18 value of 88% or more; and a gamma number of 50% or less;
wherein the treated Kraft pulp has less than 8% by weight of cellulose II as determined by x-ray crystallography; and
wherein the treated Kraft pulp is treated chemical wood pulp.
2. The treated Kraft pulp of claim 1 , wherein the treated pulp has a standard reactivity of 3.5 mL or more.
3. The treated Kraft pulp of claim 1 , wherein the treated pulp has a modified reactivity of 30 mL or more.
4. The treated Kraft pulp of claim 1 , wherein the treated pulp has a filter value Kr of 10,000 or less.
5. The treated Kraft pulp of claim 1 , wherein the treated pulp has a SEM fiber segment count of 11 or less per 100 μm 2 of a filter when the pulp is subjected to a modified reactivity test.
6. The treated Kraft pulp of claim 1 , wherein the treated pulp has a crystallite cross-section of less than 20.6 nm 2 .
7. The treated Kraft pulp of claim 1 , wherein the hemicellulose content is greater than 7%.
8. The treated Kraft pulp of claim 1 , wherein the R18 value is from 88% to 92%.
9. The treated Kraft pulp of claim 1 , wherein the treated pulp further comprises one or more of a pentosan content of from 4.6% to 9%, a xylan content of 4% to 8%, and a mannan content of 3% to 8%.
10. The treated Kraft pulp of claim 1 , wherein the treated pulp comprises a standard reactivity of 5 mL or more.
11. The treated Kraft pulp of claim 1 , wherein the treated pulp comprises a modified reactivity of 50 mL or more.
12. The treated Kraft pulp of claim 1 , wherein the treated pulp comprises a filter value Kr of 8,000 or less.
13. The treated Kraft pulp of claim 1 , wherein the treated pulp further comprises a carboxyl content of less than 3.6 meq/100 g.
14. The treated Kraft pulp of claim 1 , wherein the treated pulp further has an ASTM degree of polymerization of from 600 to 900.
15. The treated Kraft pulp of claim 1 , wherein the treated pulp further has a copper number of from 0.3 to 1.2.
16. The treated Kraft pulp of claim 1 , wherein the treated pulp has 0% cellulose II as determined by x-ray crystallography.
17. The treated Kraft pulp of claim 1 wherein the treated pulp has an ageing time of 50 hours or less to reach a target Cuox DP of 340.
18. The treated Kraft pulp of claim 1 , wherein the treated pulp further has a copper number of from 0.2 to 1.6.
19. A pulp blend comprising:
a treated Kraft pulp according to claim 1 ;
a dissolving pulp having a R18 of greater than 92%; and
a total xylan and mannan content of 6% or more;
wherein the blend comprises at least 20% by weight of the treated pulp.
20. The blend of claim 19 , further comprising a surfactant.
21. The blend of claim 19 , wherein the blend further comprises a filter value Kr of 15,000 or less.
22. The blend of claim 19 , wherein the blend further comprises a gamma number of 45.1% or more.
23. The blend of claim 19 , wherein the blend has an ageing time of 50 hours or less to reach a target Cuox DP of 340.