Aqueous process for making fluoropolymers

• US 20070135546A1
• Filed: 12/08/2006
• Published: 06/14/2007
• Est. Priority Date: 06/10/2005
• Status: Active Grant

• Current Assignee: Arkema Incorporated (Arkema)
• Original Assignee: Arkema Incorporated (Arkema)
• Inventors: Durali, Mehdi, Amin-Sanayei, Ramin, Kappler, Patrick, Burch, Greylan
• Granted Patent: US 8,080,621 B2
• Time in Patent Office: Days
• US Class Current: 524/386
• CPC Class Codes: C08F 14/18 Monomers containing fluorine
• CPC Class Codes: C08F 2/20 with the aid of macromolecular dispersing agents
• CPC Class Codes: C08F 2/30 non-ionic
• CPC Class Codes: C08F 214/22 Vinylidene fluoride
• CPC Class Codes: C08K 5/06 Ethers; Acetals; Ketals; Ortho-esters
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 27/12 containing fluorine atoms
• CPC Class Codes: C08L 27/16 Homopolymers or copolymers or vinylidene fluoride
• CPC Class Codes: C08L 71/02 Polyalkylene oxides

Abstract

A novel aqueous polymerization process for making fluoropolymer dispersions is disclosed in which non-ionic non-fluorinated emulsifier is used to produce fluoropolymer emulsions. The emulsifiers contain blocks of polyethylene glycol, polypropylene glycol and/or polytetramethylene glycol. The process and fluoropolymer produced contain no fluorinated surfactant. The fluoropolymers have excellent resistance to discoloration.

Claims

1. An aqueous fluoropolymer dispersion and resin made therefrom comprising:

a) a fluoropolymer containing at least 50 mole percent of fluoromonomer units; and

b) from 100 ppm to 2 percent, based on the weight of the fluoropolymer solids, of one or more block emulsifier(s) having at least two different blocks, and having the formula;

T₁—

[(CH₂—

CH₂—

O—

)_X]_m—

[(CH₂—

C(CH₃)—

O—

)_Y]_n—

[(CH₂—

CH₂—

CH₂—

CH₂—

O—

)_Z]_k—

T₂

wherein, X, Y, and Z are between 2 to 200; and

m, n, k are from 0 to 5, T₁ and T₂ are terminal groups selected from hydrogen, hydroxyl, carboxyl, ester, ether and/or hydrocarbon, and wherein said fluoropolymer is free of fluorosurfactants.

2. The fluoropolymer dispersion of claim 1, wherein said block emulsifier is a triblock polymer having polyethylene glycol (PEG) and polypropylene glycol (PPG) blocks.

3. The fluoropolymer of claim 2, wherein the PEG block(s) comprise less than 30 percent by weight of said triblock emulsifier.

4. The fluoropolymer of claim 3, wherein said PEG block(s) comprise less than 20 percent by weight of said triblock emulsifier.

5. The fluoropolymer of claim 4, wherein said PEG block(s) comprise less than 10 percent by weight of said triblock emulsifier.

6. The fluoropolymer of claim 2, having a central PEG block and PPG end blocks.

7. The fluoropolymer composition of claim 1 comprising from 100 ppm to I percent, based on the weight of the fluoropolymer solids, of one or more emulsifiers having polyethylene glycol, polypropylene glycol, and/or polytetramethylene glycol blocks.

8. The fluoropolymer composition of claim 1 comprising from 100 ppm to ½

percent, based on the weight of the fluoropolymer solids, of one or more emulsifiers having polyethylene glycol, polypropylene glycol, and/or polytetramethylene glycol blocks.

9. The fluoropolymer composition of claim 1, wherein said fluoropolymer contains at least 50 mole percent vinylidene fluoride monomer units.

10. The fluoropolymer composition of claim 1 wherein said emulsifier(s) have polyethylene glycol, polypropylene glycol, and/or polytetramethylene glycol blocks with repeating units of from 3 to 100.

11. A process for preparing a fluoropolymer comprising polymerizing at least one fluoromonomer in an aqueous medium comprising at least one emulsifier consisting of one or more block emulsifier(s) having at least two different blocks, and having the formula:

T₁—

[(CH₂—

CH₂—

O—

)_X]_m—

[(CH₂—

C(CH₃)—

O—

)_Y]_n—

[(CH₂—

CH₂—

CH₂—

CH₂—

O—

)_Z]_k—

T₂

wherein, X, Y, and Z are between 2 to 200; and

m, n, k are from 0 to 5, T₁ and T₂ are terminal groups selected from hydrogen, hydroxyl, carboxyl, ester, ether and/or hydrocarbon, and wherein no fluoropolymer is used in the process 10. The process of claim 9 wherein said emulsifier(s) is present in the process at from 100 ppm to 2 percent, based on the weight of the fluoropolymer solids.

12. The process of claim 11 wherein said emulsifier(s) is present in the process at from 100 ppm to I percent, based on the weight of the fluoropolymer solids, of one or more emulsifiers having polyethylene glycol, polypropylene glycol, and/or polytetramethylene glycol blocks.

13. The process of claim 11 wherein said emulsifier(s) is present in the process at from 100 ppm to ½

percent, based on the weight of the fluoropolymer solids, of one or more emulsifiers having polyethylene glycol, polypropylene glycol, and/or polytetramethylene glycol blocks.

14. The process of claim 11 wherein said fluoropolymer contains at least 50 mole percent vinylidene fluoride monomer units.

15. The process of claim 11 wherein said process is free of non-ionic, fluorinated or partially fluorinated emulsifiers.

16. The process of claim 11 wherein said emulsifier(s) contains polyethylene glycol polypropylene glycol, or polytetramethylene glycol segments with repeating units of from 3 to 100.

17. The process of claim 11, wherein said block emulsifier is a triblock polymer having polyethylene glycol (PEG) and polypropylene glycol (PPG) blocks.

18. The process of claim 17, wherein the PEG block(s) comprise less than 30 percent by weight of said triblock emulsifier.

19. The process of claim 18, wherein said PEG block(s) comprise less than 10 percent by weight of said triblock emulsifier.