Use of a polymer product for deposit formation control in manufacture of paper or board

Patent metadata

Field	Value
Publication number	US-11441273-B2
Application number	US-201716341464-A
Country	US
Kind code	B2
Filing date	Nov 22, 2017
Priority date	Nov 22, 2016
Publication date	Sep 13, 2022
Grant date	Sep 13, 2022

Abstract

The invention relates to a use of a water-soluble polymer product comprising amphoteric polyacrylamide, which has neutral or cationic net charge at pH 7, a weight-average molecular weight of 2,500,000-18,000,000 g/mol and a total ionicity of 4-28 mol-%. The polymer product is used for controlling deposit formation caused by hydrophobic substances in manufacture of paper or board, where a fibre web is formed from an aqueous suspension of fibres. The invention relates also to a method for controlling deposit formation caused by hydrophobic substances in manufacture of paper or board, where a fibre web is formed from an aqueous suspension of fibres, as well as to produced paper or board.

First claim

The invention claimed is:

1. A method to control deposit formation caused by hydrophobic substances in a process for manufacture of paper or board, the method comprising:
providing an aqueous fibre suspension;
fixing in the aqueous fiber suspension microstickies having a particle size of 3-150 μm, and pitch or colloidal stickies having a particle size of 0.2-3 μm onto the fiber by adding into the aqueous fibre suspension before a mixing chest a water-soluble polymer product comprising amphoteric polyacrylamide having a neutral or cationic net charge at pH 7, a weight-average molecular weight of 2,500,000-18,000,000 g/mol and a total ionicity of 4-28 mol-%, the amphoteric polyacrylamide comprising 3-25 mol-% of structural units derived from cationic monomers, and 0.5-5 mol-% of structural units derived from anionic monomers;
optionally diluting the aqueous fibre suspension;
delivering the aqueous fibre suspension to a headbox, and draining the aqueous fibre suspension on a wire screen to form a wet web of the paper or the paperboard; and
pressing and drying the wet web to obtain a web of the paper or the board.

2. The method according to claim 1 , wherein the amphoteric polyacrylamide has a weight-average molecular weight in a range of 3,000,000-18,000,000 g/mol.

3. The method according to claim 1 , wherein the total ionicity of the amphoteric polyacrylamide is in a range of 4-18 mol-%.

4. The method according to claim 1 , wherein 50-95% of the charged groups in the amphoteric polyacrylamide are cationic.

5. The method according to claim 1 , wherein the amphoteric polyacrylamide has a net cationic charge as measured at pH 7.

6. The method according to claim 1 , wherein the amphoteric polyacrylamide is a linear polyacrylamide.

7. The method according to claim 1 , wherein the cationic groups of the amphoteric polyacrylamide originate from monomers selected from 2-(dimethylamino)ethyl acrylate (ADAM), [2-(acryloyloxy)ethyl]trimethylammonium chloride (ADAM-Cl), 2-(dimethylamino)ethyl acrylate benzylchloride, 2-(dimethylamino)ethyl acrylate dim ethyl sulphate, 2-dimethylaminoethyl methacrylate (MADAM), [2-(methacryloyloxy)ethyl]trimethylammonium chloride (MADAM-Cl), 2-dimethylaminoethyl methacrylate dim ethyl sulphate, [3-(acryloylamino)propyl]trimethylammonium chloride (APTAC), [3-(methacryloylamino)propyl]trimethylammonium chloride (MAPTAC) and diallyldimethylammonium chloride (DADMAC).

8. The method according to claim 1 , wherein the anionic groups of the amphoteric polyacrylamide originate from monomers selected from unsaturated mono- or dicarboxylic acids selected from a group consisting of, acrylic acid, maleic acid, fumaric acid, itaconic acid, aconitic acid, mesaconic acid, citraconic acid, crotonic acid, isocrotonic acid, angelic acid and tiglic acid.

9. The method according to claim 1 , wherein the amphoteric polyacrylamide is obtained by gel polymerisation, where the content of non-aqueous solvent in the reaction mixture is less than 10 weight-%.

10. The method according to claim 1 , wherein the polymer product has a polymer content of at least 25 weight-%.

11. The method according to claim 1 , wherein the water-soluble polymer product comprising amphoteric polyacrylamide is dissolved in water so as to obtain an aqueous treatment solution, which has a pH value of 2.5-5.

12. The method according to claim 1 , further comprising adding inorganic microparticles to the fibre suspension.

13. The method according to claim 1 , wherein the fibre suspension comprises at least 50 weight-%, of recycled fibre material, being old corrugated containerboard or mixed waste, based on dry paper or paperboard.

14. The method according to claim 1 , wherein the fibre suspension comprises recycled fibre material, which comprises more than 0.02 mg/g of hydrophobic substances having particle size in the range of 10-150 μm, calculated on basis of recycled fibre material as dry, of recycled fibre material as dry.

15. The method according to claim 1 , wherein the fibre suspension comprises fibres obtained by kraft and/or mechanical pulping process(es).

16. The method according to claim 1 , wherein the amphoteric polyacrylamide is added to the fibre suspension having consistency of above 14 g/l or stock component used to prepare the fibre suspension of a paper or board machine.

17. The method according to claim 1 , wherein the amphoteric polyacrylamide is used in amount of 100-2000 g/ton produced paper or board.

18. The method according to claim 1 , wherein the amphoteric polyacrylamide in the polymer product comprises 5-14 mol-% of structural units derived from cationic monomers and 1-4 mol-% of structural units derived from anionic monomers.

Assignees

• Kemira Oyj

Inventors

• Hietaniemi Matti
• Karppi Asko
• Latvanen Maarit
• Olmos Elsa

Classifications

• D21C9/008

  Prevention of corrosion or formation of deposits on pulp-treating equipment (D21C9/08, D21H21/02 take precedence) · CPC title

• D21H17/37 Primary

  Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates · CPC title

• D21H17/375

  Poly(meth)acrylamide · CPC title

• D21F1/10

  Wire-cloths · CPC title

• D21H11/14

  Secondary fibres (working-up waste paper D21C5/02) · CPC title