Method to convert mechanical pulp derived waste material into value added cellulose products
According to an example aspect of the present invention, there is provided a process for the conversion of cellulosic waste material into a recycled cellulose product comprising the steps of cooking the waste material in a cooking liquor to remove lignin from the waste material and provide a delignified pulp, dissolving the delignified pulp in an ionic liquid to provide a spinning dope suitable for dry jet-wet spinning in an ionic liquid solution, and subjecting the spinning dope to a further processing step to provide a recycled cellulose product, said further step selected from the group of spinning cellulose fibers for use in textiles from the solution, extruding a film product for use in packaging, regenerating the dope as a hydrogel and regenerating the dope as an aerogel.
1. A process for conversion of cellulosic waste material into a recycled cellulose product comprising:
cooking the cellulosic waste material in a cooking liquor to remove lignin from the cellulosic waste material and provide a delignified pulp,
dissolving the delignified pulp in an ionic liquid to provide a spinning dope, and
forming the recycled cellulose product from the spinning dope,
wherein the cooking liquor comprises alkaline glycerol, and
wherein the alkyline glycerol comprises a glycerol to alkaline to cellulosic waste material ratio of 10 to 1.25 to 1 by weight.
2. The process according to claim 1 , wherein the cellulosic waste material is derived from mechanical pulp.
3. The process according to claim 1 , wherein the cellulosic waste material is derived from a member of the group consisting of newspaper, newspaper inserts, directories, books, magazines, catalogues, coupons, posters, and a mixture thereof.
4. The process according to claim 1 , wherein the alkaline component of the alkaline glycerol is selected from the group consisting of KOH and NaOH.
5. The process according to claim 1 , wherein the cooking is carried out at a temperature in the range of 170° C. to 180° C. for a period of from 60 to 180 minutes.
6. The process according to claim 1 , wherein the cooking liquor comprises an alkaline content, and wherein the alkaline content of the cooking liquor comprises 2 to 20 wt % of the cooking liquor.
7. The process according to claim 1 , wherein the delignified pulp comprises from 5 to 10 wt % lignin.
8. The process according to claim 1 , wherein the ionic liquid is a superbase-based ionic liquid.
9. The process according to claim 1 , wherein the ionic liquid is selected from the group consisting of [DBNH][OAc] and [MTBDH][OAc].
10. The process according to claim 1 , wherein the delignified pulp is subjected to an acid treatment to remove ash before dissolving in the ionic liquid.
11. The process according to claim 1 , wherein the delignified pulp has a viscosity of 250-700 mL/g.
12. The process according to claim 1 , wherein the spinning dope has a zero-shear viscosity in the range of 10,000 to 60,000 Pa·s.
13. The process according to claim 1 , wherein the spinning dope has a cross-over point having an angular frequency in the range of 0.2 to 5 s −1 and a dynamic modulus in the range of 1000 to 7000 Pa.
14. The process of claim 1 , wherein said forming step comprises a member selected from the group consisting of:
spinning cellulose fibers from the spinning dope,
extruding a film product from the spinning dope,
regenerating the spinning dope as a hydrogel, and
regenerating the spinning dope as an aerogel.