# US 9,434,837 B2 · Method of producing fluoropolymers using acid-functionalized monomers

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- Number: US 9,434,837 B2
- Document ID: US9434837B2
- Status: Granted
- Kind: B2
- Application number: 13/816,498
- Filed: 2011-08-30
- Published: 2013-06-13
- Granted: 2016-09-06
- Earliest claimed: 2010-09-01
- Assignees: Arkema Inc.
- Applicants: Mehdi Durali; Lotfi Hedhli
- Inventors: Mehdi Durali; Lotfi Hedhli
- Web page: https://patentgrep.com/patent/US9434837B2

## CPC

- C08L 27/16: Homopolymers or copolymers or vinylidene fluoride
- C08F 2/10: Aqueous solvent
- C08F 14/08: Vinylidene chloride
- C08F 14/22: Vinylidene fluoride
- C08F 214/22: Vinylidene fluoride
- C08F 214/225: {with non-fluorinated comonomers}
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS

## Abstract

A fluoropolymer latex is obtained by emulsion polymerization of one or more fluoromonomers in the presence of one or more acid-functionalized monomers such as vinyl sulfonic acid or a salt thereof. A fluorosurfactant need not be present.

## Claims

### Claim 1

A process for preparing a fluoropolymer in an aqueous reaction medium, comprising:
a) forming an aqueous emulsion comprising at least one radical initiator, and monomers consisting of about 0.01 to about 1 weight percent of at least one acid-functionalized monomer or salt thereof, and one or more fluoromonomers, wherein said at least one fluoromonomer comprises vinylidene fluoride; and
b) initiating polymerization of said acid-functionalized monomers and fluoromonomers, using a free-radical initiator to form a stable latex emulsion copolymer, wherein the process uses no fluorosurfactant.

### Claim 2 (depends on 1)

The process of claim 1, wherein the process uses no surfactant.

### Claim 3 (depends on 1)

The process of claim 1, wherein the aqueous emulsion additionally comprises a surfactant other than a fluorosurfactant.

### Claim 4 (depends on 1)

The process of claim 1, wherein said acid-functionalized monomer or salt thereof is functionalized with at least one acid group selected from the group consisting of sulfonic acid groups, phosphonic acid groups and carboxylic acid groups and salts thereof.

### Claim 5 (depends on 1)

The process of claim 1, wherein said acid-functionalized monomer or salt thereof is vinyl sulfonic acid or a salt thereof.

### Claim 6 (depends on 1)

The process of claim 1, wherein said acid-functionalized monomer or salt thereof is selected from the group consisting of vinyl sulfonic acid, acrylic acid, methacrylic acid, vinyl phosphonic acid, itaconic acid, and salts thereof.

### Claim 7 (depends on 1)

The process of claim 1, wherein the acid-functionalized monomer or salt thereof has a structure selected from:
R—CH═CH—SO3M;
MO3S—R—CH═CH—SO3M;
R—CH═CH—CO2M;
CH2═C(R)—CO2M;
CH2═CH—PO3M2;
R—CH═CH—PO3M2; and
R—CH═C(R)—PO3M2;
where R is a hydrogen atom or a hydrocarbon portion, and where M is a monovalent cation selected from the group consisting of hydrogen ion, alkali metal ions, ammonium ion, and monoalkyl, dialkyl, trialkyl, and tetraalkyl ammonium ions, with the alkyl parts of the monoalkyl, dialkyl, trialkyl, or tetraalkyl ammonium ion each having one to four carbon atoms.

### Claim 8 (depends on 1)

The process of claim 1 wherein said at least one acid-functionalized monomer or salt thereof is present in a total amount from about 0.01 to about 0.5 weight percent based on total monomer.

### Claim 9 (depends on 1)

The process of claim 1 wherein said at least one fluoromonomer is selected from the group consisting of vinylidene fluoride, hexafluoropropene, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, vinyl fluoride, and combinations thereof.

### Claim 10 (depends on 1)

The process of claim 1, wherein said at least one fluoromonomer comprises vinylidene fluoride and at least one comonomer selected from the group consisting of tetrafluoroethylene, trifluoroethylene, hexafluoropropene, chlorotrifluoroethylene, 3,3,3-trifluoropropene, 2,3,3,3-tetrafluoropropene, vinyl fluoride, and combinations thereof.

### Claim 11 (depends on 1)

The process of claim 1, wherein polymerization is carried out at a temperature of from about 65 to about 95 degrees Celsius.

### Claim 12 (depends on 1)

The process of claim 1, wherein the fluoropolymer is obtained in latex form.

### Claim 13 (depends on 1)

The process of claim 1, wherein at least one buffering agent is present in the aqueous emulsion in an amount effective to provide a pH of from about 4 to about 8 throughout the polymerization.