# US 6,720,360 B1 · Ultra-clean fluoropolymers

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- Number: US 6,720,360 B1
- Document ID: US6720360B1
- Status: Granted
- Kind: B1
- Application number: 09/495,600
- Filed: 2000-02-01
- Granted: 2004-04-13
- Earliest claimed: 2000-02-01
- Assignees: 3M Innovative Properties Company
- Inventors: Werner M. A. Grootaert; Georg Burkard; William D. Coggio; Klaus Hintzer; Bernhard Hirsch; Robert E. Kolb; Albert Killich; Gernot Loehr
- Web page: https://patentgrep.com/patent/US6720360B1

## CPC

- C09D 127/18: Homopolymers or copolymers of tetrafluoroethene
- C08F 6/16: Purification
- C08F 6/22: Coagulation
- C08F 14/18: Monomers containing fluorine
- C08K 5/14: Peroxides
- C08L 27/18: Homopolymers or copolymers or tetrafluoroethene
- C09D 127/12: containing fluorine atoms
- C08L 27/12: containing fluorine atoms
- C08L 2205/02: containing two or more polymers of the same C08L -group
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)

## Abstract

High purity fluoropolymers are obtained by the emulsion polymerization process, removing essentially all ions and coagulating the polymer essentially without adding ions. These polymers are useful in the field of electronic devices.

## Claims

### Claim 1

A process for preparing an ultra-clean fluoropolymer, which comprises
polymerizing one or more fluoropolymers by the aqueous emulsion polymerization process,
removing from the so-obtained latex essentially all ions different than NH4+, H+ and OH− by contacting the latex with cation and anion exchange resins, and
coagulating the fluoropolymer essentially without addition of ions.

### Claim 2 (depends on 1)

The process as claimed in claim 1, wherein the fluoropolymer is a thermoplast or an elastomer.

### Claim 3 (depends on 1)

The process as claimed in claim 1, wherein the emulsion polymerization process is performed with little or no buffer.

### Claim 4 (depends on 2)

The process as claimed in claim 2, wherein the elastomer is peroxide-curable.

### Claim 5 (depends on 2)

The process as claimed in claim 2, wherein the elastomer contains nitrile groups.

### Claim 6 (depends on 1)

The process as claimed in claim 1, wherein coagulating is effected by freeze coagulation, by a mechanical coagulation with a pressurized gas or by adding an organic water-miscible, volatile solvent selected from the group consisting of alkanols of 1 to 4 carbon atoms and ketones of 2 to 3 carbon atoms which solvents do not essentially swell the said polymer.

### Claim 7

A process for preparing an ultra-clean fluoropolymer, which comprises
polymerizing one or more fluoropolymers by the aqueous emulsion polymerization process,
removing from the so-obtained latex essentially all ions different than NH4+, H+ and OH− by contacting the latex with cation and anion exchange resins, and
coagulating the fluoropolymer essentially without adding salts or mineral acids.

### Claim 8 (depends on 7)

The process as claimed in claim 7, wherein the fluoropolymer is a thermoplast or an elastomer.

### Claim 9 (depends on 7)

The process as claimed in claim 7, wherein the emulsion polymerization process is performed with little or no buffer.

### Claim 10 (depends on 7)

The process as claimed in claim 7, wherein the fluoropolymer is a peroxide-curable elastomer.

### Claim 11 (depends on 7)

The process as claimed in claim 7, wherein the fluoropolymer is an elastomer that contains nitrile groups.

### Claim 12 (depends on 7)

The process as claimed in claim 7, wherein coagulating is effected by freeze coagulation, by a mechanical coagulation with a pressurized gas or by adding an organic water-miscible, volatile solvent selected from the group consisting of alkanols of 1 to 4 carbon atoms and ketones of 2 to 3 carbon atoms which solvents do not essentially swell the said polymer.