It is an object of the present invention to optimize a bleaching process in a step of producing phosphorylated cellulose fibers. The present invention relates to a pulp comprising cellulose fibers having 0.5 mmol/g or more of phosphoric acid groups or phosphoric acid group-derived substituents, wherein when the pulp is processed into a sheet and four sheets are laminated on one another, the ISO whiteness of the laminate is 82% or more. Moreover, when the pulp of the present invention is processed into a sheet and four sheets are then laminated on one another, the b* value of the obtained laminate according to the L*a*b* color system is 5.5 or less.

A method to prepare, pulp, and bleach cannabis bast and hurd fibers to allow for the fiber to be incorporated into absorbent cellulosic structures on a wet-laid paper machine while keeping the pectin within the fibers. The wet laid paper machine can use the ATMOS, NTT, ETAD, TAD, or UCTAD method to produce the absorbent cellulosic structure. Absorbent cellulosic structures are produced with the cannabis bast and hurd fibers or with the bast fibers alone with the hurd fibers being combined with paper mill sludge or dust to form a fuel pellet.

A method to prepare, pulp, and bleach cannabis bast and hurd fibers to allow for the fiber to be incorporated into absorbent cellulosic structures on a wet-laid paper machine while keeping the pectin within the fibers. The wet laid paper machine can use the ATMOS, NTT, ETAD, TAD, or UCTAD method to produce the absorbent cellulosic structure. Absorbent cellulosic structures are produced with the cannabis bast and hurd fibers or with the bast fibers alone with the hurd fibers being combined with paper mill sludge or dust to form a fuel pellet.

A method for continuously providing a treated cellulose-comprising starting material (110), in particular as starting material for manufacturing a cellulosic molded body (102), is provided. The method comprises: i) supplying (10) a cellulose-comprising starting material (101), which in particular is a solid matter, with a predefined composition to a reactor device (105), ii) continuously treating (20) the starting material (101) in the reactor device (105), to obtain the treated cellulose-comprising starting material (110), and iii) discharging (30) the treated cellulose-comprising starting material (110) from the reactor device (105).

A method for continuously providing a treated cellulose-comprising starting material (110), in particular as starting material for manufacturing a cellulosic molded body (102), is provided. The method comprises: i) supplying (10) a cellulose-comprising starting material (101), which in particular is a solid matter, with a predefined composition to a reactor device (105), ii) continuously treating (20) the starting material (101) in the reactor device (105), to obtain the treated cellulose-comprising starting material (110), and iii) discharging (30) the treated cellulose-comprising starting material (110) from the reactor device (105).

A method for providing a treated cellulose-comprising mixed starting material (110), in particular a mixed starting material (110) for forming a, in particular regenerated, cellulosic molded body (102) is described. The method comprises: i) providing (10) a first starting material (101a) which comprises a lignocellulosic raw material, ii) providing (1) a second starting material (101b) which comprises a cellulose-containing lignin-free product, iii) mixing (15) the first starting material (101a) and the second starting material (101b) to a mixed starting material (101), and iv) at least partially commonly treating (20) the first starting material (101a) and the second starting material (101b) for obtaining the treated mixed starting material (101), in particular a mixed pulp.

A method for providing a treated cellulose-comprising mixed starting material (110), in particular a mixed starting material (110) for forming a, in particular regenerated, cellulosic molded body (102) is described. The method comprises: i) providing (10) a first starting material (101a) which comprises a lignocellulosic raw material, ii) providing (1) a second starting material (101b) which comprises a cellulose-containing lignin-free product, iii) mixing (15) the first starting material (101a) and the second starting material (101b) to a mixed starting material (101), and iv) at least partially commonly treating (20) the first starting material (101a) and the second starting material (101b) for obtaining the treated mixed starting material (101), in particular a mixed pulp.

The present invention relates to a method for bleaching an unbleached or pre-bleached paper pulp comprising at least the following consecutive steps: a) preparing an unbleached or pre-bleached paper pulp having a pH of at least 8, b) bringing the paper pulp obtained at the end of step a) into contact with chlorine dioxide, c) when the pH of the paper pulp obtained from step b) is lower than 10, adding at least one Brønsted base to the paper pulp, d) adding hydrogen peroxide to the paper pulp obtained at the end of step c), e) maintaining the paper pulp obtained at the end of step d) in a first bleaching tower, f) optionally, adding sulphuric acid to the paper pulp obtained at the end of step e) and maintaining the obtained paper pulp in a second bleaching tower, the method dispensing with the need for a step of washing the paper pulp before the end of step e), and, if applicable, before the end of step f).

Recycle fiber bleaching includes an oxygen pre-treatment to activate the fiber for further bleaching. A preferred method of making a high brightness papermaking pulp from recycled cellulose fiber includes: (a) pre-treating a first recycled cellulosic fiber mix with oxygen, said first recycled cellulosic fiber mix having a first high Kappa number prior to pre-treatment and a reduced Kappa number after pre-treatment that is lower than said first high Kappa number; and (b) blending the pre-treated first recycled cellulosic fiber mix with the reduced Kappa number with a second recycled cellulosic fiber mix having a second Kappa number lower than the first high Kappa number of the first recycled cellulosic fiber mix; and (c) oxidatively bleaching the blended recycled cellulosic fiber mix of step (b); and optionally (d) reductively bleaching the blended recycled cellulosic fiber mix of step (c).

Recycle fiber bleaching includes an oxygen pre-treatment to activate the fiber for further bleaching. A preferred method of making a high brightness papermaking pulp from recycled cellulose fiber includes: (a) pre-treating a first recycled cellulosic fiber mix with oxygen, said first recycled cellulosic fiber mix having a first high Kappa number prior to pre-treatment and a reduced Kappa number after pre-treatment that is lower than said first high Kappa number; and (b) blending the pre-treated first recycled cellulosic fiber mix with the reduced Kappa number with a second recycled cellulosic fiber mix having a second Kappa number lower than the first high Kappa number of the first recycled cellulosic fiber mix; and (c) oxidatively bleaching the blended recycled cellulosic fiber mix of step (b); and optionally (d) reductively bleaching the blended recycled cellulosic fiber mix of step (c).