Use of diallyldimethylammonium chloride acrylamide dispersion copolymer in a papermaking process

• US 6,238,521 B1
• Filed: 05/21/1999
• Issued: 05/29/2001
• Est. Priority Date: 05/01/1996
• Status: Expired due to Term

• Current Assignee: Ecolab USA Incorporated (Ecolab, Inc.)
• Original Assignee: Nalco Chemical Company (Ecolab, Inc.)
• Inventors: Nagarajan, Ramasubramanyam, Maltesh, Chidambaram, Shing, Jane B. Wong
• Primary Examiner(s): Chin, Peter
• Application Number:
  US09/316,372
• Time in Patent Office: 739 Days
• Field of Search: 162/168.1, 162/175, 162/158, 162/164.1, 162/168.3, 162/164.3, 162/181.6, 162/164.6, 162/181.8, 162/183, 162/168.2
• US Class Current: 162/164.1
• CPC Class Codes: D21H 17/37 Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• CPC Class Codes: D21H 17/375 Poly(meth)acrylamide
• CPC Class Codes: D21H 17/455 comprising tertiary amine or being at least partially quaternised
• CPC Class Codes: D21H 17/675 Oxides, hydroxides or carbonates
• CPC Class Codes: D21H 17/68 siliceous, e.g. clays
• CPC Class Codes: D21H 21/10 Retention agents or drainage improvers
• CPC Class Codes: D21H 23/14 by selecting point of addition or time of contact between components

Abstract

A papermaking process consisting essentially of:

forming an aqueous cellulosic papermaking slurry;

adding to the slurry certain additives, with said certain additives selected from the group including: coagulants; sizing agents; and mineral fillers;

draining the slurry to form a sheet; and

drying the sheet to form a paper sheet;

the improvement comprising adding to the slurry, prior to it being drained; an effective amount of a cationic dispersion polymer; which cationic dispersion polymer is a copolymer comprising about 30 mole % diallyldimethylammonium chloride (DADMAC) and about 70 mole % acrylamide (AcAm); and

adding to the slurry, either before or after said cationic dispersion polymer is added and the slurry is drained,

a microparticle selected from the group consisting of

a) copolymers of acrylic acid and acrylamide;

b) bentonite; and

c) dispersed silica;

with the proviso that said coagulant cannot be a cationic dispersion copolymer comprising about 30 mole % diallyldimethylammonium chloride (DADMAC) and about 70 mole % acrylamide (AcAm).

Claims

1. In a papermaking process consisting essentially of:

forming an aqueous cellulosic papermaking slurry;

adding to the slurry certain additives, with said certain additives selected from the group including;

coagulants;

sizing agents; and

mineral fillers;

draining the slurry to form a sheet; and

drying the sheet to form a paper sheet;

the improvement comprising adding to the slurry, prior to it being drained;

from about 0.02 lbs polymer/ton to about 20 lbs polymer/ton of a cationic dispersion polymer;

which cationic dispersion polymer is a copolymer comprising about 30 mole % diallyldimethylammonium

chloride (DADMAC) and about 70 mole % acrylamide (AcAm); and

dispersion polymer has an RSV of about 5.0 dl/g; and

adding to the slurry, either before or after said cationic dispersion polymer is added and the slurry is drained,

from about 0.05 lbs microparticle/ton to about 25.0 lbs microparticle/ton of a microparticle selected from the group consisting of

a) copolymers of acrylic acid and acrylamide;

b) bentonite; and

c) dispersed silica;

with the proviso that said coagulant cannot be a cationic dispersion copolymer comprising about 30 mole % diallyldimethylammonium chloride (DADMAC) and about 70 mole % acrylamide (AcAm).

2. The process of claim 1 wherein said microparticle is a copolymer of acrylic acid and acrylamide.

3. The process of claim 1 wherein said microparticle is bentonite.

4. The process of claim 1 wherein said microparticle is dispersed silica.

5. The process of claim 1 wherein said aqueous cellulose papermaking slurry comprises pulps which pulps are selected from the group consisting of chemical pulps;

thermo-mechanical pulps;

mechanical pulps;

recycle pulps and ground wood pulps.

6. The process of claim 5 wherein said aqueous cellulose papermaking slurry comprises pulps which pulps are selected from the group consisting of chemical pulps and recycle pulps.

7. The process of claim 1 wherein one of said certain additives is a mineral filler wherein the mineral filler is selected from the group consisting of titanium dioxide, clay, talc, calcium carbonate and combinations thereof.

8. The process of claim 7 wherein said mineral filler is added to the slurry in an amount of from about 2 to about 50 parts per hundred parts by weight of dry pulp contained in the slurry.

9. The process of claim 1 in which one of said certain additives is a coagulant selected from the group consisting of starch;

alum; and

low molecular weight cationic synthetic polymers, wherein said low molecular weight cationic synthetic polymer is selected from the group consisting of epichlorohydrin-dimethylamine polymer, a poly diallyldimethylammonium chloride polymer and a polyethyleneimine polymer.

10. The process of claim 9 in which said coagulant is starch.

11. The process of claim 9 in which said coagulant is an epichlorohydrin-dimethylamine polymer.

12. The process of claim 1 in which said microparticle is added to the slurry after said polymer is added to the slurry.

13. The process of claim 1 in which said microparticle is added to the slurry before said polymer is added to the slurry.

14. The process according to claim 1 wherein said chemical pulps are selected from the group consisting of sulfate and sulfite pulps from both hard and soft woods.