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1. WO2020112003 - PROCÉDÉ DE PRODUCTION D'HOLOCELLULOSE ET AGENT DE RÉSISTANCE POUR PAPIER, PROCÉDÉ DE PRODUCTION DE PAPIER, PAPIER PRODUIT ET UTILISATION DU PAPIER PRODUIT

Note: Texte fondé sur des processus automatiques de reconnaissance optique de caractères. Seule la version PDF a une valeur juridique

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CLAIMS

1. Method of producing holocellulose fibres useable in a process for the production of paper by treating a wood-based raw material with an organic peroxide, such as peracetic acid (PAA), wherein the method comprises:

i. charging the organic peroxide continuously to the wood-based raw

material during the treatment; and/or

ii. charging the organic peroxide to the wood-based raw material in at least two separate steps with an intermediate alkaline treatment step.

2. Method according to claim 1, wherein the intermediate alkaline treatment step is

performed at a pH of pH 8 or more, or from pH 10-12, a temperature of 15-100°C at atmospheric pressure, and for a duration of at least 1 hour.

3. Method according to claim 1 or 2, wherein in at least one of the at least two separate steps of organic peroxide treatment, the organic peroxide is charged batchwise or continuously to the wood-based raw-material during the treatment.

4. Method according to any one of claims 1-3, wherein the organic peroxide treatment is performed at a temperature of 40 to 90 °C or 55 to 75°C.

5. Method according to any one of claims 1-4, wherein the organic peroxide treatment is performed at a pH of 2.5 to 5 or 4.0 to 4.8.

6. Method according to any one of claims 1-5, wherein the continuous charging is

performed at one or more charge rates during the whole treatment.

7. Method of producing a paper strength agent useable in a process for the production of paper comprising producing holocellulose fibres according to the method of any one of claims 1 to 6, optionally microfibrillating the holocellulose fibres to provide

holocellulose nanofibrils (CNF), drying the holocellulose fibres or the holocellulose nanofibrils and reslushing the dried holocellulose fibres or the holocellulose nanofibrils.

8. Process for the production of paper comprising the steps of:

a. Preparing a papermaking stock comprising an aqueous pulp slurry comprising cellulosic fibres and having a fibre consistency of from 0.1 to 40 % by weight, wherein the cellulosic fibres comprise or consist of wood-based holocellulose

fibres, and wherein the amount of the wood-based holocellulose fibres is from 0.5 to 100% by weight, based on the total weight of the cellulosic fibres, b. providing the stock to a wire and form a web,

c. dewatering the web, and

d. drying the web.

9. Process according to claim 8, wherein the wood-based holocellulose fibres are

produced by treating a wood-based raw material with an organic peroxide, preferably peracetic acid (PAA).

10. Process according to claim 8 or 9, wherein the holocellulose fibres are produced by the method according to any one of claims 1 to 6.

11. Process according to any one of the preceding claims 8 to 10, wherein the wood-based raw material for the holocellulose fibres comprises hardwood and/or softwood material.

12. Process according to any one of the preceding claims 8 to 11, wherein the holocellulose fibres are added after a refining step in the step a) of preparing the stock.

13. Process according to any one of the preceding claims 8 to 12, wherein the step a) of preparing the papermaking stock comprises a step of adding to the aqueous slurry an additive, beating and/or refining the aqueous slurry.

14. Process according to claim 13, wherein the additive comprises the holocellulose fibres which are added in an amount of 0.5 to 80% by weight, or from 2 to 60% by weight or from 4 to 55% by weight, based on the dry weight of the cellulosic fibres.

15. Process according to any one of claims 13 or 14, wherein the additive comprises a dry strength agent chosen from nanocellulosic materials, charged and non-charged starch, gum derivatives, synthetic copolymers with acrylamide and combinations thereof.

16. Process according to any of the preceding claims 13 to 15, wherein the additive

comprises a cationic starch.

17. Process according to claim 16, wherein the cationic starch is added in an amount of 0.5 to 5% by weight, based on the dry weight of the cellulosic fibres.

18. Process according to any of the preceding claims 13 to 17, wherein the additive

comprises a holocellulose CNF.

19. Process according to claim 18, wherein the holocellulose CNF is added in an amount of 0.1 to 10% by weight, or from 0.5 to 5% by weight, based on the dry weight of the stock.

20. Process according to any one of the preceding claims 13-19, wherein the additive

comprises a wet strength agent, which is a resin chosen from urea-formaldehyde resins, melamine-formaldehyde resins, polyamide-amine-epichlorohydrine resins and combinations thereof.

21. Process according to any one of the preceding claims 13-20, wherein the additive

comprises a retention aid chosen from charged or non-charged polyacrylamide (PAM), polyethyleneimine (PEI), colloidal silica (CS), bentonite, and combinations thereof.

22. Process according to claim 13-21, wherein the additive is cationic polyacrylamide

(CPAM).

23. Process according to any one of the preceding claims 8 to 22, wherein the cellulosic fibres comprise fibres from a kraft pulp, soda pulp, sulfite pulp, mechanical pulp, thermomechanical pulp, semi-chemical or chemi-thermomechanical pulp, recycled pulp or mixtures thereof in an amount of from 0-99,5% by weight, based on the total weight of the cellulosic fibres.

24. Paper obtained by the process according to any one of claims 8 to 23.

25. Use of the paper of claim 24 as a packaging material.

26. Use of the paper of claim 24 as a corrugated fibreboard.

27. Use of wood-based holocellulose fibres, the holocellulose fibres produced by treating a wood-based raw material with an organic peroxide in a process comprising a

delignification and a washing step, in a papermaking process for improving strength of paper.