Synthesis of surfactant-free poly (vinylidene fluoride) latexes via raft emulsion polymerization

Patent metadata

Field	Value
Publication number	US-11326008-B2
Application number	US-201816649686-A
Country	US
Kind code	B2
Filing date	Sep 21, 2018
Priority date	Sep 27, 2017
Publication date	May 10, 2022
Grant date	May 10, 2022

Abstract

The present invention relates to a process for producing a stable fluorinated latex by emulsion polymerization in the absence of fluorinated surfactant, stabilized by an amphiphilic block copolymer formed in situ. The invention also concerns the aqueous dispersion comprising the fluorinated polymer chains and the amphiphilic block copolymers, obtained by this process.

First claim

The invention claimed is:

1. A process for producing a stable vinylidene fluoride polymer latex by emulsion polymerization in the absence of fluorinated surfactant, said process comprising the steps of:
a) providing a PEG-based hydrophilic macroRAFT forming a first hydrophilic block,
b) synthesis of a vinylidene fluoride polymer and chain extension of said hydrophilic block with vinylidene fluoride monomer, alone or in combination with at least one other ethylenically unsaturated comonomer, in the presence of initiator, and optionally of a chain transfer agent and/or a antifoulant, forming a second hydrophobic block,

said hydrophilic and hydrophobic blocks composing an amphiphilic block copolymer anchored to the vinylidene fluoride polymer particles, the weight ratio initiator/macroRAFT in step b ranging from 1 to 4, and wherein said hydrophilic block comprises
i) a poly(ethylene glycol) methyl ether modified with xanthate, and has the formula below:

or

ii) a di-hydroxy-poly(ethylene glycol) carrying a xanthate groups on each chain end, and having the formula below:

within R′ is alkyl or aryl; R″ is —C(═O)—C(CH 3 )—; R is OH, O-alkyl, O-aryl or a polymer, and n is an integer of 1 or more.

2. The process of claim 1 , wherein vinylidene fluoride polymer formed in step b includes both homopolymers of vinylidene fluoride and copolymers containing at least 50 mole percent of vinylidene fluoride copolymerized with at least one ethylenically unsaturated monomer selected from the group consisting of: tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinylfluoride, pentafluoropropene, perfluoromethyl vinyl ether, perfluoropropyl vinyl ether, (meth)acrylic acid and (meth)acrylic esters such as alkyl(meth)acrylates, vinyl esters such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl benzoate, maleic esters such as dimethyl maleate, diethyl maleate, di-n-propyl maleate, diisopropyl maleate, di-2-methoxyethyl maleate, fumaric esters such as dimethyl fumarate, diethyl fumarate, di-n-propyl fumarate, diisopropyl fumarate, styrene, vinyltoluene, alpha-methylstyrene, acrylonitrile, anhydrides, vinyl esters, alpha-olefins, substituted or unsubstituted mono and dialkyl esters of unsaturated dicarboxylic acids, vinyl aromatics, and cyclic monomers.

3. The process of claim 1 , wherein said initiator is a persulfate salt, selected from the group consisting of sodium persulfate, potassium persulfate, or ammonium persulfate, the amount of persulfate salt added to the reaction mixture, based upon the total weight of monomer added to the reaction mixture, being from 0.005 to 1.0 weight percent.

4. The process of claim 1 , wherein said initiator is an organic peroxide selected from the group consisting of alkyl, dialkyl, or diacyl peroxide, peroxydicarbonates, and peroxy esters, said organic peroxide used in an amount from about 0.5 to about 2.5 weight percent on total weight of monomer added to the reaction mixture.

5. The process of claim 1 , wherein said latex particles of vinylidene fluoride polymer have an average particle size comprised between 20 and 300 nm.

6. The process of claim 1 , wherein said latex particles of vinylidene fluoride polymer have a solid content of 1 to 60 weight percent.

7. An aqueous dispersion obtained by the process of claim 1 comprising particles of vinylidene fluoride polymer, residues of initiator, and an amphiphilic block copolymer composed of a hydrophilic block containing units of PEG and of a hydrophobic block composed of vinylidene fluoride monomer, alone or in combination with at least one other ethylenically unsaturated comonomer.

8. The aqueous dispersion of claim 7 , wherein said particles of vinylidene fluoride polymer have an average particle size from 20 to 300 nm, said dispersion having a solid content of 1 to 60 weight percent, and are free of fluorinated surfactant.

9. A membrane comprising the aqueous dispersion of claim 7 .

10. A coating comprising the aqueous dispersion of claim 7 .

11. A film comprising the aqueous dispersion of claim 7 .

Assignees

• Arkema France

Inventors

• Devisme Samuel
• Kahn Andrew
• Fuentes-Exposito Mathieu
• Mckenna Timothy
• D'Agosto Franck
• Lansalot Muriel
• Bonnet Anthony

Classifications

• C08K5/36

  Sulfur-, selenium-, or tellurium-containing compounds {(C08K5/0091 takes precedence)} · CPC title

• C09D127/16

  Homopolymers or copolymers of vinylidene fluoride · CPC title

• C08F2810/40

  taking place solely at one end or both ends of the polymer backbone, i.e. not in the side or lateral chains · CPC title

• C08F214/225 Primary

  with non-fluorinated comonomers · CPC title

• C08L53/00

  Compositions of block copolymers containing at least one sequence of a polymer obtained by reactions only involving carbon-to-carbon unsaturated bonds; Compositions of derivatives of such polymers · CPC title