Method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in papermaking

Patent metadata

Field	Value
Publication number	US-9487916-B2
Application number	US-201313919167-A
Country	US
Kind code	B2
Filing date	Jun 17, 2013
Priority date	Sep 12, 2007
Publication date	Nov 8, 2016
Grant date	Nov 8, 2016

Abstract

The invention provides a method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a papermaking process The method improves the efficiency of drainage aids or wet web strength aids or wet strength aid by coating at least some of the filler particles with a material that prevents the filler materials form adhering to a those additives. The drainage additive or wet web strength additive or wet strength aid holds the cellulose fibers together tightly and is not wasted on the filler particles.

First claim

The invention claimed is:

1. A method of papermaking, the method comprising the steps of:
treating filler particles in a container with a composition of matter in the absence of cellulose fiber stock by
contacting the filler particles with a rotating admixing apparatus having a distribution head rotating at a rotational speed of 1800 to 3000 rpm while the filler particles are in the container,
combining the treated filler particles with the cellulose fiber stock thereby forming a combination,
treating the combination with at least one wet strength aid or wet web strength additive or drainage additive, and
forming a paper mat from the combination,

wherein the filler particles are selected from precipitated calcium carbonate, ground calcium carbonate, and any combination thereof, the cellulose fiber stock comprises a plurality of cellulose fibers and water, and the composition of matter enhances the performance of the wet strength aid or wet web strength additive or drainage additive in the paper mat,
the distribution head is rotated by a drive, the distribution head is arranged in the container containing a slurry of the filler particles, and the distribution head is associated with a rotational plane, and the distribution head has, along a circumference thereof, which surrounds a rotational axis, distributed outlets from which the composition is passed into the container bearing a slurry of filler particles and mixing blades, characterized in that the outlets are formed as openings and the mixing blades are formed as strips extending transverse to the rotational plane and having a length equal at least half of an inner diameter of the container;
and the composition is dispersed by the distribution head to the filler particles.

2. The method of claim 1 in which the paper mat is formed by removing some of the water from the combination.

3. The method of claim 1 in which at least some of the calcium carbonate is in one form selected from the list consisting of: undispersed calcium carbonate, dispersed slurry calcium carbonate, chalk, and any combination thereof.

4. The method of claim 1 in which at least a portion of the calcium carbonate is in a dispersed slurry calcium carbonate form, the dispersed slurry calcium carbonate further comprising at least one item selected from: polyacrylic acid polymer dispersants, sodium polyphosphate dispersants, Kaolin clay slurry, and any combination thereof.

5. The method of claim 1 in which the blend of filler particles is 50% ground calcium carbonate and 50% precipitated calcium carbonate.

6. The method of claim 1 in which the composition of matter is a coagulant.

7. The method of claim 1 in which the composition of matter is a coagulant selected from the list consisting of: inorganic coagulants, organic coagulants, condensation polymerization coagulants, and any combination thereof.

8. The method of claim 1 in which the composition of matter is a coagulant having a molecular weight range of between 200 and 1,000,000.

9. The method of claim 1 in which the composition of matter is a coagulant selected from the list consisting of: alum, sodium aluminate, polyaluminum chlorides, aluminum chlorohydroxide, aluminum hydroxide chloride, polyaluminum hydroxychloride, sulfated polyaluminum chlorides, polyaluminum silica sulfate, ferric sulfate, ferric chloride, epichlorohydrin-dimethylamine (EPI-DMA), EPI-DMA ammonia crosslinked polymers, polymers of ethylene dichloride and ammonia, polymers of ethylene dichloride, polymers of dimethylamine, condensation polymers of multifunctional diethylenetriamine, condensation polymers of multifunctional tetraethylenepentamine, condensation polymers of multifunctional hexamethylenediamine condensation polymers of multifunctional ethylenedichloride, melamine polymers, formaldehyde resin polymers, cationically charged vinyl addition polymers, and any combination thereof.

10. The method of claim 1 in which the composition of matter is an AcAm/DADMAC copolymer.

11. The method of claim 1 in which the drainage additive or wet web strength additive or wet strength aid is one selected from the list of: glyoxylated Acrylamide/DADMAC copolymer, poly-vinylamine, poly-vinylamide, poly-diallylamine, and any combination thereof.

12. The method of claim 1 in which the ratio of drainage additive or wet web strength additive or wet strength aid relative to the solid portion of the paper mat is 0.3 to 5 kg of strength additive per ton of paper mat.

13. The method of claim 1 in which at least some of the filler particles are GCC.

14. The method of claim 1 in which none of the filler particles are PCC.

15. The method of claim 1 in which the paper mat has a solid portion and the filler particles in the paper mat comprise more than 50% of the combined mass of the solid portion of the paper mat.

16. The method of claim 1 in which the drainage additive or wet web strength additive or wet strength aid and the composition of matter carry the same charge.

17. The method of claim 1 in which the blend of filler particles further comprises one item selected from the list consisting of: organic pigment, inorganic pigment, clay, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, and any combination thereof.

18. A method of papermaking comprising the use of filler, the method comprising the steps of:
treating filler particles in a container with a composition of matter in the absence of cellulose fiber stock by
contacting the filler particles with a rotating admixing apparatus while the filler particles are in the container,
combining the treated filler particles with the cellulose fiber stock thereby forming a combination,
treating the combination with at least one dry strength aid, and
forming a paper mat from the combination,
wherein at least 10% of the filler particles are in a dispersed slurry calcium carbonate form,
the cellulose fiber stock comprises a plurality of cellulose fibers and water, and
the composition of matter enhances the performance of the dry strength aid in the paper mat
the rotating admixing apparatus having a distribution head, the distribution head rotated by a drive at a rotational speed of 1800 to 3000 rpm, the distribution head is arranged in the container containing a slurry of the filler particles, and the distribution head is associated with a rotational plane, and the distribution head has, along a circumference thereof, which surrounds a rotational axis, distributed outlets from which the composition is passed into the container bearing a slurry of filler particles and mixing blades, characterized in that the outlets are formed as openings and the mixing blades are formed as strips extending transverse to the rotational plane and having a length equal at least half of an inner diameter of the container;
and the composition is dispersed by the distribution head to the filler particles.

19. A method of increasing the interactions between a drainage additive or wet web strength additive or wet strength aid and cellulose fibers mixed with filler particles, the method comprising the steps of:
pre-treating filler particles in a container with a composition of matter in the absence of cellulose fiber stock, the composition delivered by a rotating admixing apparatus,
combining the pre-treated filler particles with cellulose fibers to form a combination, and
treating the combination with at least one drainage additive or wet web strength additive or wet strength aid,
wherein the filler particles are selected from

Assignees

• Nalco Co

Inventors

• Zhao Yulin
• Li Jun
• Rao Qing Long
• Ashton Stephen
• Cheng Weiguo
• Todorovic Aleksandar
• Smith Alan

Classifications

• D21C5/00

  Other processes for obtaining cellulose, e.g. cooking cotton linters (obtaining fibres for spinning D01C); {Processes characterised by the choice of cellulose-containing starting materials} · CPC title

• D21H17/69

  modified, e.g. by association with other compositions prior to incorporation in the pulp or paper · CPC title

• D21H17/74 Primary

  of organic and inorganic material · CPC title

• D21C5/025

  De-inking · CPC title

• D21H17/66

  Salts, e.g. alums · CPC title