Method for producing paper with a high substance weight

• US 8,152,962 B2
• Filed: 12/01/2005
• Issued: 04/10/2012
• Est. Priority Date: 12/03/2004
• Status: Active Grant

• Current Assignee: Solenis Technologies LP (Innovative Water Care, LLC)
• Original Assignee: BASF AG (BASF SE)
• Inventors: Koch, Oliver, Blum, Rainer, Van Dijk, Ron
• Primary Examiner(s): Hug, Eric
• Assistant Examiner(s): Chin, Peter
• Application Number:
  US11/720,814
• Publication Number:
  US 20100147475A1
• Time in Patent Office: 2,322 Days
• Field of Search: 162/164.3, 162/164.6, 162/166, 1621682-1686, 162/183, 210/727, 210/728, 210734-736, 526/303.1, 526/307, 526/307.1, 526/307.2, 526/307.3, 526/307.4, 526/310
• US Class Current: 162/164.6
• CPC Class Codes: D21H 17/33 Synthetic macromolecular compounds
• 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 21/10 Retention agents or drainage improvers
• CPC Class Codes: D21H 23/04 Addition to the pulp; After-treatment of added substances in the pulp

Abstract

A process for producing paper of high basis weight by draining a paper pulp on a wire in the presence of a combination of at least two polymers as a retention and drainage aid system, forming sheets, and drying the sheets, which comprises forming the sheets in the absence of finely divided inorganic flocculants and using as retention and drainage aids

(a) at least one amino-containing polymer

and

(b) at least one branched cationic polyacrylamide.

Claims

1. A process for producing paper of high basis weight comprising draining a paper pulp comprising waste paper on a wire in the presence of a combination of at least two polymers as a retention and drainage aid system, forming sheets, and drying the sheets, which comprises forming the sheets in the absence of finely divided inorganic flocculants and in the presence of retention and drainage aids comprising (a) at least one amino-containing polymer and (b) at least one branched cationic polyacrylamide having an ionic regain of >

20%

wherein the basis weight of the paper is at least 300 g/m² and

wherein the amino-containing polymer is a polyethylenimine or a modified polyethylenimine.

2. The process according to claim 1, wherein the modified polyethylenimine is obtained by reacting a polyamidoamine compound with a polyalkylene oxide derivative whose terminal hydroxyl groups have been reacted with epichlorohydrin.

3. The process according to claim 1, wherein the amino-containing polymer has been subjected to ultrafiltration.

4. The process according to claim 1, wherein the branched cationic polyacrylamide is a cationic copolymer of acrylamide and an unsaturated cationic ethylene monomer.

5. The process according to claim 4, wherein the unsaturated cationic ethylene monomer is selected from dimethylaminoethyl acrylate methochloride and dimethylaminoethylacrylamide methochloride.

6. The process according to claim 4, wherein methylenebisacrylamide is used as a branching agent.

7. The process according to claim 1, wherein the branched cationic polyacrylamide has an ionic regain RI of >

40%.

8. The process according to claim 1, wherein the branched cationic polyacrylamide is a mixture of a branched cationic polyacrylamide and a linear polyacrylamide in a ratio of 99:

1 to 1;

2.

9. The process according to claim 1, wherein components (a) and (b) of the retention and drainage aid system are used, based on one metric tonne of dry paper, in an amount of (a) 100 g to 3 kg solids-and (b) 50 g to 800 g.

10. The process according to claim 1, wherein components (a) and (b) of the retention and drainage aid system are used, based on one metric tonne of dry paper, in an amount of (a) 150 g to 2.0 kg and (b) 65 g to 600 g.

11. The process according to claim 1, wherein said branched cationic polyacrylamide having an ionic regain of ≦

50%.