# US 5,708,131 A · Amorphous copolymers of tetrafluoroethylene and hexafluoropropylene

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- Number: US 5,708,131 A
- Document ID: US5708131A
- Status: Granted
- Kind: A
- Application number: 08/639,453
- Filed: 1996-04-29
- Granted: 1998-01-13
- Earliest claimed: 1995-02-06
- Assignees: E. I. Du Pont de Nemours and Company
- Inventors: Richard Alan Morgan
- Web page: https://patentgrep.com/patent/US5708131A

## CPC

- C08F 214/26: Tetrafluoroethene
- C08F 6/22: Coagulation
- C09D 127/18: Homopolymers or copolymers of tetrafluoroethene
- Y10T 428/2933: Coated or with bond, impregnation or core
- Y10T 428/3154: Of fluorinated addition polymer from unsaturated monomers
- Y10T 428/31544: Addition polymer is perhalogenated
- Y10T 428/31699: Ester, halide or nitrile of addition polymer
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- 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)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

Tetrafluoroethylene polymer resin is isolated from aqueous dispersion by first freezing the dispersion, followed by thawing the dispersion which enables removal of the water and water soluble impurities from the resin particles.

## Claims

### Claim 1

A process for isolating non-fibrillatible tetrafluoroethylene copolymer resin from aqueous dispersion produced by dispersion polymerization, comprising first freezing said dispersion to form frozen dispersion, then thawing said frozen dispersion to form thawed frozen dispersion, and then separating said resin from liquid of said thawed frozen dispersion.

### Claim 2 (depends on 1)

The process of claim 1, wherein said liquid is removed from said polymer resin immediately after said frozen dispersion becomes said thawed frozen dispersion.

### Claim 3 (depends on 1)

The process of claim 1, wherein said liquid is removed simultaneously with said thawing and with washing of said resin.

### Claim 4 (depends on 1)

The process of claim 1, wherein said freezing is done by rotating a chilled roll in said dispersion to form a layer of said frozen dispersion on the surface of said roll, and wherein said layer is scraped from said surface of said roll before said surface re-enters said dispersion.

### Claim 5

A process for isolating non-fibrillatible tetrafluoroethylene copolymer resin from aqueous dispersion produced by dispersion polymerization, consisting essentially of first freezing said dispersion to form frozen dispersion, then thawing said frozen dispersion, and separating said resin from liquid of the resultant thawed frozen dispersion.

### Claim 6 (depends on 5)

The process of claim 5 and washing said resin from said resultant thawed frozen dispersion.

### Claim 7 (depends on 6)

The process of claim 6 wherein said thawing and separating are carried out simultaneously and said washing is carried out simultaneously with said thawing and separating.