Processing of chemically modified cellulosic fibres
A chemically modified cellulosic fibre or filament having a moisture content of at least 7% by weight obtained by a process comprising the steps of (i) obtaining cellulosic fibres or filament and chemically modifying the cellulose by substitution to increase its absorbency; (ii) washing the fibres after step (i) in a mixture comprising water and up to 99% by weight of water-miscible organic solvent; (iii) drying the fibres to a moisture content of at least 7% by weight.
1. A process for processing a cellulosic fibre or a cellulosic filament, the process comprising:
chemically modifying the cellulose of the cellulosic fibre or the cellulosic filament by substitution to increase absorbency;
washing the chemically modified cellulosic fibre or chemically modified cellulosic filament in a wash solution comprising up to 99% by weight of an organic solvent and at least 95% by weight of the organic solvent; and
adjusting the washed fibre or washed filament to a moisture content of at least 7% by weight.
2. The process of claim 1 , wherein the washed fibre or washed filament is dried to a moisture content from 11% to 18% by weight.
3. The process of claim 1 , wherein the adjusting step comprises drying the washed fibre or washed filament.
4. The process of claim 3 , further comprising carding the dried fibre or dried filament to make a nonwoven web of fibre.
5. The process of claim 4 , further comprising needling the nonwoven web of fibre to form a wound dressing.
6. The process of claim 5 , further comprising sealing the wound dressing in a pouch that maintains the moisture content of the wound dressing in a sterile environment.
7. The process of claim 1 , wherein the adjusting step comprises conditioning the washed fibre or washed filament in an atmosphere having a relative humidity of at least 40%.
8. The process of claim 7 , wherein the relative humidity is from 45% to 85%.
9. The process of claim 7 , further comprising carding the conditioned fibre or filament to produce a non-woven web of chemically modified cellulosic fibre.
10. A process for producing a non-woven web of chemically modified cellulosic fibres, the process comprising:
neutralizing chemically modified cellulosic fibres;
finishing the chemically modified cellulosic fibres with a solution comprising less than 99% by weight of an organic solvent to produce finished chemically modified cellulosic fibres;
adjusting the moisture content of the finished chemically modified cellulosic fibres to a moisture content from 11% to 20% by weight;
processing the finished chemically modified cellulosic fibres into the non-woven web of chemically modified cellulosic fibres, and wherein the moisture content of the non-woven web of chemically modified cellulosic fibres is from 11% to 20% by weight; and
packaging the non-woven web of chemically modified cellulosic fibres in a pouch that maintains the moisture content of the non-woven web of chemically modified cellulosic fibres in a sterile environment, and wherein the packaged non-woven web of chemically modified cellulosic fibres has a tensile strength of at least 3N per cm,
wherein the solution comprises at least 95% by weight of the organic solvent.
11. The process of claim 10 , wherein the solution comprises less than 95% by weight of an organic solvent.
12. The process of claim 10 , wherein the adjusting step comprises drying the finished chemically modified cellulosic fibres to achieve the moisture content from 11% to 20% by weight.
13. The process of claim 10 , wherein the adjusting step comprises conditioning the finished chemically modified cellulosic fibres in air having a relative humidity of at least 40% to achieve the moisture content from 11% to 20% by weight.
14. The process of claim 13 , wherein the relative humidity is from 45% to 85%.
15. The process of claim 10 , wherein the adjusting step comprises drying the finished chemically modified cellulosic fibres in air having a relative humidity of at least 40% to achieve the moisture content from 11% to 20% by weight.
16. A non-woven web of chemically modified cellulosic fibres produced by the process of claim 10 .
17. The non-woven web of chemically modified cellulosic fibres of claim 16 , wherein the non-woven web of chemically modified cellulosic fibres has a tensile strength from 3N/cm to 25N/cm.
18. The non-woven web of chemically modified cellulosic fibres of claim 16 , wherein the non-woven web of chemically modified cellulosic fibres has a basis weight from 80 gsm to 120 gsm.
19. The non-woven web of chemically modified cellulosic fibres of claim 16 , wherein the tensile strength is in a cross-direction.