# US 5,708,071 A · Aqueous dispersion of an amphoteric water-soluble polymer, a method of manufacturing the same, and a treating agent comprising the same

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- Number: US 5,708,071 A
- Document ID: US5708071A
- Status: Granted
- Kind: A
- Application number: 08/571,070
- Filed: 1995-12-12
- Granted: 1998-01-13
- Earliest claimed: 1994-12-15
- Assignees: Hymo Corporation
- Inventors: Hisao Takeda
- Web page: https://patentgrep.com/patent/US5708071A

## CPC

- C08F 220/34: Esters containing nitrogen {, e.g. N,N-dimethylaminoethyl (meth)acrylate}
- C02F 1/56: Macromolecular compounds
- D21H 17/37: Polymers of unsaturated acids or derivatives thereof, e.g. polyacrylates
- D21H 17/41: containing ionic groups
- D21H 21/10: Retention agents or drainage improvers
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C02F: TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE (separation in general B01D; special arrangements on waterborne vessels of installations for treating water, waste water or sewage, e.g. for producing fresh water, B63J; adding materials to water to prevent corrosion C23F; treating radioactively-contaminated liquids G21F9/04; regeneration of reactants for recirculation into processes, see the relevant places for the processes)
- 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

## Abstract

A storage stable, flowable aqueous dispersion of an amphoteric water-soluble polymer with good handling as well as a method of manufacturing the same are provided. Such an aqueous dispersion can be effectively used for flocculating and/or dehydrating sludge, or for separating and treating oil-containing industrial waste water, as a drainage aid, a retention aid, or recovering substances from white water in the papermaking process. The aqueous dispersion of an amphoteric water-soluble polymer is obtained by polymerizing a mixture of monomers comprising a specific cationic monomer and an anionic monomer as essential components wish stirring in an aqueous salt solution incapable of dissolving the produced polymer and in the presence of a polymer electrolyte dispersant soluble in said aqueous salt solution. Such an aqueous dispersion is highly effective when the concentration of the produced amphoteric water soluble polymer in the aqueous dispersion, the concentration of the salt, the concentration of the dispersant, the viscosity of the aqueous dispersion, and the average diameter of the particles of the amphoteric water-soluble polymer in the aqueous dispersion are found within specific ranges.

## Claims

### Claim 1

An aqueous dispersion of an amphoteric water-soluble polymer polymerization product of a mixture of monomers comprising a cationic monomer expressed by the formula (I), ##STR3## , where A is O or NH; B is an alkyl group of 2.about.3 carbon atoms: R.sub.1 is H or CH.sub.3 ; R.sub.2 and R.sub.3 are each an alkyl group of 1.about.2 carbon atoms; X.sup.- is an anionic counter ion, and an anionic monomer as essential components in an aqueous salt solution incapable of dissolving the polymer and in the presence of a polymer electrolyte dispersant soluble in said aqueous salt solution, said aqueous dispersion having characteristic properties which are that (1) the concentration of the amphoteric water-soluble polymer in the aqueous dispersion is 5 wt % or more, than (2) the average particle diameter of the particle of the amphoteric water-soluble polymer in the aqueous dispersion is 0.1.about.150 .mu.m, that (3) the viscosity of the aqueous dispersion is 10-3000 cp, that (4) the concentration of the salt in the aqueous dispersion is 15 wt %-saturation concentration, and that (5) the concentration of the dispersant in the aqueous dispersion based on the amphoteric water-soluble polymer is 1-15 wt %.

### Claim 2 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1, wherein said mixture of monomers comprises monomer of said formula (I) monomer of the formula (II), ##STR4## , where A is O or NH; B is an alkyl group of 2.about.3 carbon atoms; R.sub.1 is H or CH.sub.3 ; R.sub.2 and R.sub.3 are each an alkyl group of 1-2 carbon atoms; R.sub.4 is an alkyl group of 1.about.2 carbon atoms; X.sup.- is an anionic counter ion; (meth)acrylamide and an anionic monomer.

### Claim 3 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1 or, wherein said anionic monomer comprises a monomer selected from the group consisting of itaconic acid, (math)acrylic anionic monomer and a mixture thereof.

### Claim 4 (depends on 3)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 3, wherein said anionic monomer is itaconic acid.

### Claim 5 (depends on 3)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 3, wherein said anionic monomer is a (meth)acrylic anionic monomer.

### Claim 6 (depends on 5)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 5, wherein said (meth)acrylic anionic monomer is a monomer selected from the group consisting of (meth)acrylic acid, 2-acrylamide-2-methylpropane sulfonic acid and a mixture thereof.

### Claim 7 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1, wherein the total gram equivalent value of said cationic monomer(s) in said amphoteric water-soluble polymer is greater than the total gram equivalent value of said anionic monomer(s) in said amphoteric water-soluble polymer.

### Claim 8 (depends on 2)

An aqueous dispersion of an amphomeric water-soluble polymer according to claim 2, wherein said cationic monomer expressed by the formula (II) is acryloyloxyethyltrimethylammonium salt.

### Claim 9 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1, wherein said cationic monomer expressed by the formula (I) is acryloyloxyethyldimethylbenzyl ammonium salt.

### Claim 10 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1, wherein said diapersant is one or more than one cationic polymer electrolytes.

### Claim 11 (depends on 1)

An aqueous dispersion of an amphoteric water-soluble polymer according to claim 1, wherein said dispersant is a (co)polymer of one or more than one monomer selected from the group consisting of dimethylaminoethyl(meth)acrylate chloride or sulfate, dimethylaminopropyl(meth)acrylamide chloride or sulfate, (meth)acryloyloxyethyltrimethylammonium chloride, (meth)acrylamidepropyltrimethylammonium chloride, dimethyldiarylammonium chloride in a mole ratio of 50 mole % to 100 mole %, and acrylamide in a mole ratio of 50 mole % to 0 mole %.

### Claim 12

A method of manufacturing a stably storable and easily flowable aqueous dispersion of an amphoteric water-soluble polymer, characterized in polymerizing a mixture of monomers comprising a cationic monomer expressed by the formula (I), ##STR5## , where A is O or NH; B is an alkyl group of 2-3 carbon atoms; R.sub.1 is H or CH.sub.3 ; R.sub.2 and R.sub.3 are each an alkyl group of 1.about.2 carbon atoms; X.sup.- is an anionic counter ion, and an anionic monomer as essential components with stirring in an aqueous salt solution incapable of dissolving the produced polymer and in the presence of a polymer electrolyte dispersant soluble in said aqueous salt solution.

### Claim 13 (depends on 12)

A method of manufacturing an aqueous dispersion of an amphoteric water-soluble polymer according to claim 12, characterized by polymerization of a mixture of monomers comprising anionic monomers expressed by said formula (I) and the formula (II), ##STR6## , where A is O or NH; B is an alkyl group of 2.about.3 carbon atoms; R.sub.1 is H or CH.sub.3 : R.sub.2 and R.sub.3 are each an alkyl group of 1-2 carbon atoms; R.sub.4 is an alkyl group of 1-2 carbon atoms; X.sup.- is an anionic counter ion, (meth)acrylamide and an anionic monomer as essential components.

### Claim 14 (depends on 12)

A method of manufacturing an aqueous dispersion of an amphoteric water-soluble polymer according to claim 12, wherein a further amount of salt is added to the aqueous dispersion of an amphoteric water-soluble polymer obtained by polymerization.

### Claim 15 (depends on 1)

A flocculating agent to be used in the treatment of municipal sewage, human waste, general industrial waste water or other waste water, said agent comprising an aqueous dispersion of an amphoteric water-soluble polymer according to claim 1.

### Claim 16 (depends on 1)

A flocculating and/or dehydrating agent to be used in the treatment of municipal sewage, human waste, general industrial waste water or other waste water before processing at a decanter, belt press, filter press or screw press dehydrators, said agent comprising an aqueous dispersion an amphoteric water-soluble polymer according to claim 1.

### Claim 17 (depends on 1)

An oil separating agent to be used in the process of separating oil from oil-containing industrial waste water, said agent comprising an aqueous dispersion of an amphoteric water-soluble polymer according to any of claim 1.

### Claim 18 (depends on 1)

A drainage aid to be used for producing paper from pulp stuff in a papermaking process, said agent comprising an aqueous dispersion of an amphoteric water-soluble polymer according to claim 1.

### Claim 19 (depends on 1)

A retention aid for retaining additives to paper in the papermaking process for producing paper, said agent comprising an aqueous dispersion of an amphoteric water-soluble polymer according to claim 1.

### Claim 20 (depends on 1)

A chemical composition for recovering useful and valuable substances from white water discharged in the papermaking process, said agent comprising an aqueous dispersion of an amphoteric water-soluble polymer according to claim 1.