US 12,448,730 B2
Preparation of cellulose fibers
Per Vinther, Høng (DK); and John Mark Lawther, Roskilde (DK)
Assigned to JENA TRADING APS, Høng (DK)
Appl. No. 17/424,962
Filed by Jena Trading ApS, Høng (DK)
PCT Filed Jan. 21, 2020, PCT No. PCT/EP2020/051429
§ 371(c)(1), (2) Date Jul. 22, 2021,
PCT Pub. No. WO2020/152178, PCT Pub. Date Jul. 30, 2020.
Claims priority of application No. 19153123 (EP), filed on Jan. 22, 2019.
Prior Publication US 2022/0081833 A1, Mar. 17, 2022
Int. Cl. D21C 5/00 (2006.01); D21C 9/00 (2006.01); D21C 9/02 (2006.01); D21C 9/08 (2006.01); D21C 9/10 (2006.01); D21C 9/16 (2006.01); D21C 9/18 (2006.01)
CPC D21C 5/005 (2013.01) [D21C 9/007 (2013.01); D21C 9/02 (2013.01); D21C 9/08 (2013.01); D21C 9/1005 (2013.01); D21C 9/1052 (2013.01); D21C 9/163 (2013.01); D21C 9/18 (2013.01)] 13 Claims
 
1. A method of isolating and preparing cellulose fibers of a desired length-weighted average fiber length lc(l) from cereal straw, the method comprising:
(i) subjecting the cereal straw to a pretreatment comprising a dry mechanical treatment to remove parts of the cuticular wax from the cereal straw followed by enzymatic pretreatment using one or more protease and/or pectinase enzymes in aqueous suspension to remove remaining cuticular wax from the cereal straw, thus obtaining a solution comprising dewaxed straw material in aqueous suspension,
(ii) solubilizing hemicellulose and lignin components of the solution in (i) by adjusting the pH and increasing the temperature of the solution to pH 9-11.5 and temperature of 65-95° C. to provide a material,
(iii) separating the material obtained in (ii) into a solid cellulose fiber fraction and a liquid fraction comprising solubilized hemicellulose and lignin components,
(iv) suspending the solid cellulose fiber fraction obtained in (iii) in an aqueous liquid, adjusting the temperature and pH of the aqueous liquid to a temperature of 65-95° C. and pH 9-11.5, adding a bleaching agent, and keeping the cellulose fiber fraction in suspension for 60-180 minutes (T1) to provide a bleached material,
(v) subjecting the bleached material obtained in (iv) to a wet mechanical refining treatment to provide a bleached-refined material,
(vi) continuing bleaching at a temperature 65-95° C. and a pH 9-11.5 for a duration of 20-90 minutes (T3) without wet mechanical treatment,
(vii) obtaining a cellulose fiber product by separating the bleached-refined material obtained in (vi) into a bleached-refined solid cellulose fiber fraction and an aqueous bleaching liquor fraction, and
(viii) optionally washing the bleached-refined cellulose fiber fraction in an aqueous liquid,
wherein the length-weighted fiber length lc(l) of the cellulose fibers is >0.6 mm.