Method for producing paper, paperboard and cardboard having high dry strength

• US 8,647,470 B2
• Filed: 10/14/2010
• Issued: 02/11/2014
• Est. Priority Date: 10/20/2009
• Status: Active Grant

• Current Assignee: Solenis Technologies LP (Olympus Water Holdings IV LP)
• Original Assignee: BASF SE
• Inventors: Esser, Anton
• Primary Examiner(s): HUG, JOHN ERIC
• Application Number:
  US13/502,885
• Publication Number:
  US 20120205065A1
• Time in Patent Office: 1,216 Days
• Field of Search: 162/146, 162/157.6, 162/157.7, 162/168.1, 162/168.2, 162/168.3, 162/182, 162/185, 162/187, 162/183, 162175-177, 977/762, 977/788, 977/895, 977/896, 977/961, 977/963
• US Class Current: 162/157.6
• CPC Class Codes: D21H 17/37 Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
• CPC Class Codes: D21H 17/42 anionic
• CPC Class Codes: D21H 17/44 cationic
• CPC Class Codes: D21H 21/18 Reinforcing agents

Abstract

Process for the production of paper, board and cardboard having high dry strength by addition of an aqueous composition comprising a nanocellulose and at least one polymer selected from the group consisting of the anionic polymers and water-soluble cationic polymers, draining of the paper stock and drying of the paper products.

Claims

1. A process for the production of paper, board, and cardboard having high dry strength, the process comprising:

(I) metering into a paper stock an aqueous composition comprising a nanocellulose comprising cellulose fibers and at least one anionic polymer and optionally a water-soluble cationic polymer;

(II) draining the paper stock, to obtain paper product; and

(III) drying the paper product;

wherein the anionic polymer comprises, as polymerized units;

(a) at least one monomer selected from the group consisting of a C₁- to C₂₀-alkyl acrylate, a C₁- to C₂₀-alkyl methacrylate, a vinyl ester of a saturated carboxylic acid comprising up to 20 carbon atoms, a vinylaromatic comprising up to 20 carbon atoms, an ethylenically unsaturated nitrile, a vinyl ester of a saturated, monohydric alcohol comprising 1 to 10 carbon atoms, a vinyl halide, and an aliphatic hydrocarbon comprising 2 to 8 carbon atoms and one or two double bonds;

(b) at least one anionic monomer selected from the group consisting of an ethylenically unsaturated C₃- to C₈-carboxylic acid, a vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, vinylphosphonic acid, and salts thereof;

(c) optionally, at least one monomer selected from the group consisting of a C₁- to C₁₀-hydroxyalkyl acrylate, a C₁- to C₁₀-hydroxyalkyl methacrylate, acrylamide, methacrylamide, an N—

C₁- to C₂₀-alkylacrylamide, and an N—

C₁- to C₂₀-alkylmethacrylamide; and

(d) optionally, a monomer comprising at least two ethylenically unsaturated double bonds in the molecule.

2. The process of claim 1, wherein the nanocellulose has a length dimension below 1000 μ

m and a fiber thickness in a range from 50 μ

m to 3 nm.

3. The process of claim 2, wherein at least 80% of the cellulose fibers of the nanocellulose have a fiber thickness in a range from 50 μ

m to 3 nm.

4. The process of claim 3, wherein at least 80% of the cellulose fibers of the nanocellulose have a fiber thickness in a range from 1 μ

m to 5 nm.

5. The process of claim 1, wherein the nanocellulose has a length dimension below 1000 μ

m a fiber thickness in a range from 50 μ

m to 3 nm, and

wherein the nanocellulose further comprises from 5 ppm to 2% by weight of an ionic fluid, based on a total mass of the nanocellulose.

6. The process of claim 5, wherein at least 80% of the cellulose fibers of the nanocellulose have a fiber thickness of from 50 μ

M to 3 nm and comprise from 5 ppm to 2% by weight of an ionic liquid, based on a total mass of the nanocellulose.

7. The process of claim 1, wherein the anionic polymer comprises, as polymerized units:

(c) at least 60 mol % of at least one monomer selected from the group consisting of a C₁- to C₂₀-alkyl acrylate, a C₁- to C₂₀-alkyl methacrylate, vinyl acetate, vinyl propionate, styrene, α

-methylstyrene, p-methylstyrene, α

-butylstyrene, 4-n-butylstyrene, 4-n-decylstyrene, acrylonitrile, methacrylonitrile, butadiene, and isoprene; and

(d) from 0.5 to 9 mol % of an ethylenically unsaturated C₃- to C₅-carboxylic acid.

8. The process of claim 1, wherein the anionic polymer comprises, as polymerized units, at least 80 mol % of a monomer of group (a).

9. The process of claim 1, wherein the anionic polymer comprises, as monomer of group (a), a mixture comprising, as polymerized units:

(i) at least one selected from the group consisting of a C₁- to C₂₀-alkyl acrylate and a C₁- to C₂₀-alkyl methacrylate; and

(ii) at least one selected from the group consisting of styrene, α

-methylstyrene, p-methylstyrene, α

-butylstyrene, 4-n-butylstyrene, butadiene and isoprene,

wherein a weight ratio of (i) to (ii) is from 10;

90 to 90;

10, based on a total weight of the mixture.

10. The process of claim 1, wherein a molar mass M_w of the cationic polymer is in the range from 5000 to 5 million g/mol.

11. The process of claim 1, wherein a charge density of the cationic polymer is in a range from 0.5 to 23 meq/g.

12. The process of claim 1, wherein the water-soluble cationic polymer comprises a polymer comprising a vinylamine unit.

13. The process of claim 2, wherein the nanocellulose has a length dimension in a range from 100 nm to 500 μ

m and a fiber thickness in a range from 1 μ

m to 5 nm.

14. The process of claim 2, wherein the nanocellulose has a length dimension in a range from 100 nm to 100 μ

m and a fiber thickness in a range from 1 μ

m to 5 nm.

15. The process of claim 2, wherein the nanocellulose has a length dimension in a range from 100 nm to 50 μ

m and a fiber thickness in a range from 1 μ

m to 5 nm.

16. The process of claim 2, wherein the nanocellulose has a length dimension in a range from 100 nm to 10 μ

m and a fiber thickness in a range from 1 μ

m to 5 nm.

17. An aqueous composition, comprising:

a nanocellulose comprising cellulose fibers, wherein at least 80% of the cellulose fibers have a fiber thickness of from 50 μ

m to 3 nm, and from 5 ppm to 2% by weight of an ionic liquid, based on a total mass of the nanocellulose;

at least one anionic polymer; and

optionally, a water-soluble cationic polymer;

wherein the anionic polymer comprises, as polymerized units;

(a) at least one monomer selected from the group consisting of a C₁- to C₂₀-alkyl acrylate, a C₁- to C₂₀-alkyl methacrylate, a vinyl ester of a saturated carboxylic acid comprising up to 20 carbon atoms, a vinylaromatic comprising up to 20 carbon atoms, an ethylenically unsaturated nitrile, a vinyl ester of a saturated, monohydric alcohol comprising 1 to 10 carbon atoms, a vinyl halide, and an aliphatic hydrocarbon comprising 2 to 8 carbon atoms and one or two double bonds;

(b) at least one anionic monomer selected from the group consisting of an ethylenically unsaturated C₃- to C₈-carboxylic acid, a vinylsulfonic acid, acrylamido-2-methylpropanesulfonic acid, styrenesulfonic acid, vinylphosphonic acid, and salts thereof;

(c) optionally, at least one monomer selected from the group consisting of a C₁- to C₁₀-hydroxyalkyl acrylate, a C₁- to C₁₀-hydroxyalkyl methacrylate, acrylamide, methacrylamide, an N—

C₁- to C₂₀-alkylacrylamide, and an N—

C₁- to C₂₀-alkylmethacrylamide; and

(d) optionally, a monomer comprising at least two ethylenically unsaturated double bonds in the molecule.