Browse Prior Art Database

USE OF CELLULASE TO IMPROVE VISCOSITY CONTROL OF KRAFT DISSOLVING PULP

IP.com Disclosure Number: IPCOM000243903D
Publication Date: 2015-Oct-27

Publishing Venue

The IP.com Prior Art Database

Related People

Pedro Emanuel Garcia Loureiro: AUTHOR [+3]

This text was extracted from a PDF file.
This is the abbreviated version, containing approximately 6% of the total text.

Page 01 of 34

14006

5

10

15

20

25

30

USE OF CELLULASE TO IMPROVE VISCOSITY CONTROL OF KRAFT DISSOLVING PULP

Reference to sequence listing

     This application contains a Sequence Listing in computer readable form. The computer readable form is incorporated herein by reference.

FIELD OF THE INVENTION

     The present invention relates to treatment of unbleached or partially bleached kraft dis- solving pulp with one or more cellulases. The cellulase treatment results in improved viscosity control, reduced viscosity and/or increased reactivity of the dissolving pulp.

BACKGROUND OF THE INVENTION

Commercial dissolving pulp or dissolving-grade pulp is a chemical bleached pulp with a

high cellulose content enough to be suitable for the production of regenerated cellulose and cel- lulose derivatives. Commercial dissolving pulp has special properties, such as a high level of brightness and uniform molecular-weight distribution. Commercial dissolving pulp is manufac- tured for uses that require a high chemical cellulose purity, and particularly low hemicellulose content, since the chemically similar hemicellulose can interfere with subsequent processes.

Dissolving pulp is so named because it is not made into paper, but dissolved either in a solvent or by derivatization into a homogeneous solution, which makes it completely chemically acces- sible and removes any remaining fibrous structure. Once dissolved, it can be spun into textile fibers such as viscose or Lyocell, or chemically reacted to produce derivatized celluloses, such as cellulose triacetate, a plastic-like material formed into fibers or films, or cellulose ethers such

as methyl cellulose, used as a thickener.

     Conventional viscose manufacturing which uses dissolving pulps as raw material re- quires improvement with respect to its environmental impact as well as its production costs. The present invention provides a cellulase-based solution that improves the viscosity control in the production of bleached dissolving kraft pulp and the reactivity of the final dissolving pulp thereby

reducing the amount of chemicals used in the viscose production process and/or improving the processability in terms of viscose dope filterability in the viscose making process. Savings in the amount of chemicals utilized in the production of regenerated cellulose such as carbon disulfide (CS2) in the viscose making process will reduce costs and the environmental impact.

Although it has been previously demonstrated that a cellulase can be used to decrease the

pulp viscosity and/or increase dissolving pulp reactivity, such previous studies were based on the treatment of bleached dissolving pulps or commercial dissolving pulps. The present inven- tion demonstrates that a cellulase can be applied instead earlier in the dissolving pulp produc-

1


Page 02 of 34

14006

5

10

15

20

25

30

35

tion process in order to improve the viscosity control during the production process of the dis- solving pulp by allowing a more precise control...