# US 11,441,273 B2 · Use of a polymer product for deposit formation control in manufacture of paper or board

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- Number: US 11,441,273 B2
- Document ID: US11441273B2
- Status: Granted
- Kind: B2
- Application number: 16/341,464
- Filed: 2017-11-22
- Published: 2021-09-30
- Granted: 2022-09-13
- Earliest claimed: 2016-11-22
- Assignees: Kemira Oyj
- Applicants: Kemira Oyj
- Inventors: Matti Hietaniemi; Asko Karppi; Maarit Latvanen; Elsa Olmos
- Web page: https://patentgrep.com/patent/US11441273B2

## CPC

- D21H 21/02: Agents for preventing deposition on the paper mill equipment, e.g. pitch or slime control (removal of fats, resins, pitch, or waxes D21C9/08)
- C08F 220/56: Acrylamide; Methacrylamide
- D21C 9/008: {Prevention of corrosion or formation of deposits on pulp-treating equipment (D21C9/08, D21H21/02 take precedence)}
- D21C 9/08: Removal of fats, resins, pitch or waxes; {Chemical or physical purification, i.e. refining, of crude cellulose by removing non-cellulosic contaminants, optionally combined with bleaching (fats, waxes C11B; natural resins C09F1/00; hemicellulose C08B37/14; purification by mechanical means D21D5/00)}
- D21F 1/022: {Means for injecting material into flow within the headbox}
- D21F 1/10: Wire-cloths
- D21H 11/14: Secondary fibres (working-up waste paper D21C5/02)
- D21H 17/37: Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
- D21H 17/375: {Poly(meth)acrylamide}
- D21H 17/43: Carboxyl groups or derivatives thereof
- D21H 17/455: {comprising tertiary amine or being at least partially quaternised}
- D21H 17/68: siliceous, e.g. clays
- D21H 17/74: {of organic and inorganic material}
- D21H 23/04: Addition to the pulp; After-treatment of added substances in the pulp
- C08F 2800/20: as weight or mass percentages
- C08L 33/26: Homopolymers or copolymers of acrylamide or methacrylamide
- Y02W 30/64: Paper recycling
- D21H: PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- D21C: PRODUCTION OF CELLULOSE BY REMOVING NON-CELLULOSE SUBSTANCES FROM CELLULOSE-CONTAINING MATERIALS; REGENERATION OF PULPING LIQUORS; APPARATUS THEREFOR
- D21F: PAPER-MAKING MACHINES; METHODS OF PRODUCING PAPER THEREON
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- Y02W: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT

## 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.

## Claims

### Claim 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.

### Claim 2 (depends on 1)

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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 1)

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

### Claim 5 (depends on 1)

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

### Claim 6 (depends on 1)

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

### Claim 7 (depends on 1)

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).

### Claim 8 (depends on 1)

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.

### Claim 9 (depends on 1)

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-%.

### Claim 10 (depends on 1)

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

### Claim 11 (depends on 1)

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.

### Claim 12 (depends on 1)

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

### Claim 13 (depends on 1)

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.

### Claim 14 (depends on 1)

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.

### Claim 15 (depends on 1)

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

### Claim 16 (depends on 1)

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.

### Claim 17 (depends on 1)

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

### Claim 18 (depends on 1)

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.