Method of manufacturing fluoroelastomers

Patent metadata

Field	Value
Publication number	US-10882935-B2
Application number	US-201616061965-A
Country	US
Kind code	B2
Filing date	Dec 14, 2016
Priority date	Dec 14, 2015
Publication date	Jan 5, 2021
Grant date	Jan 5, 2021

Abstract

The invention pertains to a method for manufacturing a fluoroelastomer (A), wherein fluoroelastomer (A) is a (per)fluoroelastomer, where such method includes
(a): polymerizing in an aqueous emulsion in the presence of a surfactant by feeding the following ingredients into a first reactor:
(i) a monomer mixture (M1) comprising at least one monomer (F), wherein monomer (F) is a fluoromonomer, (ii) at least one iodinated and/or brominated chain-transfer agent(s), (iii) at least one branching agent possessing at least two ethylenic unsaturations; and (iv) at least one radical initiator,
so as to obtain a pre-polymer latex (P);
(b): recovering latex (P) from the first reactor and storing the recovered latex (P) in a storage tank; (c): feeding the recovered latex (P) from the storage tank into a second reactor; (d): polymerizing in the second reactor at least a second monomer mixture (M2) comprising at least one monomer (F) in the presence of a radical initiator, so as to obtain a final latex (F); and (d): recovering (per)fluoroelastomer from latex (F).

First claim

The invention claimed is:

1. A method for manufacturing fluoroelastomer (A), wherein fluoroelastomer (A) is a (per)fluoroelastomer, the method comprising:
(a): polymerizing in an aqueous emulsion in the presence of a surfactant by feeding the following ingredients into a first reactor:
(i) a monomer mixture (M1) comprising at least one monomer (F), wherein monomer (F) is a fluoromonomer,
(ii) at least one iodinated and/or brominated chain-transfer agent(s),
(iii) at least one branching agent possessing at least two ethylenic unsaturations;
and
(iv) at least one radical initiator,

so as to obtain a pre-polymer latex (P), wherein pre-polymer latex (P) comprises particles of a pre-polymer having a number-averaged molecular weight of at least 1000 and at most 40000;
(b): recovering latex (P) from the first reactor and storing the recovered latex (P) in a storage tank;
(c): feeding the recovered latex (P) from the storage tank into a second reactor;
(d): polymerizing in the second reactor at least a second monomer mixture (M2) comprising at least one monomer (F) in the presence of a radical initiator, so as to obtain a final latex (F); and
(e): recovering fluoroelastomer (A) from latex (F).

2. The method of claim 1 , wherein monomer mixture (M1) comprises at least one fluoromonomer selected from the group consisting of:
C 2 -C 8 perfluoroolefins;
C 2 -C 8 hydrogen-containing fluoroolefins;
(per)fluoroalkylethylenes complying with formula CH 2 ═CH-R f0 , in which R f0 is a C 1 -C 6 (per)fluoroalkyl or a C 1 -C 6 (per)fluorooxyalkyl having one or more ether groups;
chloro- and/or bromo- and/or iodo-C 2 -C 6 fluoroolefins;
fluoroalkylvinylethers complying with formula CF 2 ═CFOR f1 in which R f1 is a C 1 -C 6 fluoro- or perfluoroalkyl;
hydrofluoroalkylvinylethers complying with formula CH 2 ═CFOR f1 in which R f1 is a C 1 -C 6 fluoro- or perfluoroalkyl;
fluoro-oxyalkylvinylethers complying with formula CF 2 ═CFOX 0 , in which X 0 is a C 1 -C 12 oxyalkyl, or a C 1 -C 12 (per)fluorooxyalkyl having one or more ether groups;
fluoroalkyl-methoxy-vinylethers complying with formula CF 2 ═CFOCF 2 OR f2 in which R f2 is a C 1 -C 6 fluoro- or perfluoroalkyl, or a C 1 -C 6 (per)fluorooxyalkyl having one or more ether groups;
functional fluoro-alkylvinylethers complying with formula CF 2 ═CFOY 0 , in which Y 0 is a C 1 -C 12 alkyl or (per)fluoroalkyl, or a C 1 -C 12 oxyalkyl or a C 1 -C 12 (per)fluorooxyalkyl, said Y 0 group comprising a carboxylic or sulfonic acid group, in its acid, acid halide or salt form;
fluorodioxoles, of formula:

wherein each of R f3 , R f4 , R f5 , R f6 , equal or different each other, is independently a fluorine atom, a C 1 -C 6 fluoro- or per(halo)fluoroalkyl, optionally comprising one or more oxygen atom.

3. The method of claim 2 , wherein mixture (M1) is selected from the group consisting of:
(1) vinylidene fluoride (VDF) containing monomers mixtures, in which VDF is mixed with at least one comonomer different from VDF and selected from the group consisting of:
(a) C 2 -C 8 perfluoroolefins;
(b) hydrogen-containing C 2 -C 8 fluoro-olefins or perfluoroalkyl ethylenes of formula CH 2 ═CH-R f , wherein R f is a C 1 -C 6 perfluoroalkyl group;
(c) C 2 -C 8 chloro and/or bromo and/or iodo-fluoroolefins;
(d) (per)fluoroalkylvinylethers (PAVE) of formula CF 2 ═CFOR f , wherein R f is a C 1 -C 6 (per)fluoroalkyl group;
(e) (per)fluoro-oxy-alkylvinylethers of formula CF 2 ═CFOX, wherein X is a C 1 -C 12 ((per)fluoro)-oxyalkyl comprising catenary oxygen atoms;
(per)fluorodioxoles having formula:

wherein R f3 , R f4 , R f5 , R f6 , equal or different from each other, are independently selected from fluorine atoms and C 1 -C 6 (per)fluoroalkyl groups, optionally comprising one or more than one oxygen atom;

(g) (per)fluoro-methoxy-vinylethers (MOVE, hereinafter) having formula:
CFX 2 =CX 2 OCF 2 OR″ f wherein R″ f is selected among C 1 -C 6 (per)fluoroalkyls , linear or branched; C 5 -C 6 cyclic (per)fluoroalkyls; and C 2 -C 6 (per)fluorooxyalkyls, linear or branched, comprising from 1 to 3 catenary oxygen atoms, and X 2 is F or H;
(h) C 2 -C 8 non-fluorinated olefins (Ol);
(i) ethylenically unsaturated compounds comprising nitrile (—CN) groups, optionally (per)fluorinated; and
(2) tetrafluoroethylene (TFE) containing monomers mixtures, in which TFE is mixed with at least one comonomer different from TFE and selected from the group consisting of monomers of classes (a), (c), (d), (e), (g), and (i), as above detailed.

4. The method according to claim 1 , wherein step (a) comprises polymerizing the mixture (M1) in an aqueous emulsion in the presence of a fluorinated surfactant (FS) selected from the group consisting of:
CF 3 (CF 2 ) n1 COOM′, in which n 1 is an integer ranging from 4 to 10; and M′ represents H, NH 4 , Na, Li or K;
T(C 3 F 6 O) n0 (CFXO) m0 CF 2 COOM″ [formula (FS 1 )], in which T represents Cl or a perfluoroalkoxyde group of formula C k F 2k+1 O wherein k is an integer from 1 to 3, one F atom being optionally substituted by a Cl atom; n 0 is an integer ranging from 1 to 6 ; m 0 is an integer ranging from 0 to 6; M″ represents H, NH 4 , Na, Li or K; and X represents F or CF 3 ;
F—(CF 2 —CF 2 ) n2 —CH 2 —CH 2 —RO 3 M″′, in which R is P or S, M″′ represents H, NH 4 , Na, Li or K; and n 2 is an integer ranging from 2 to 5;
A—R f —B bifunctional fluorinated surfactants, in which A and B, equal to or different from each other, are —(O) p CFX—COOM*; M* represents H, NH 4 , Na, Li or K; X is F or CF 3 ; p is an integer equal to 0 or 1; and R f is a linear or branched perfluoroalkyl chain, or a (per)fluoropolyether chain such that the number average molecular weight of A—R f —B is in the range 300 to 3,000;
R′ f —O—(CF 2 ) r —O—L—COOM′, wherein R′ f is a linear or branched perfluoroalkyl chain, optionally comprising catenary oxygen atoms, M′ is H, NH 4 , Na, Li or K; r is 1 to 3; L is a bivalent fluorinated bridging group;
R″ f —(OCF 2 ) u —O—(CF 2 ) v —COOM″, wherein R″ f is a linear or branched perfluoroalkyl chain, optionally comprising catenary oxygen atoms, M″ is H, NH 4 , Na, Li or K; u and v are integers from 1 to 3;
R″′ f —(O) t —CHQ—L—COOM′″, wherein R″′ f is a linear or branched perfluoroalkyl chain, optionally comprising catenary oxygen atoms, Q is F or CF 3 , t is 0 or 1, M′″ is H, NH 4 , Na, Li or K; L is a bivalent fluorinated bridging group;
cyclic fluorocompounds of the following formula (I):

wherein X 1 , X 2 , X 3 , equal or different from each other are independently selected from H, F, and C 1-6 (per)fluoroalkyl groups, optionally comprising one or more catenary or non-catenary oxygen atoms; L represents a bond or a divalent group; R F is a divalent fluorinated C 1-3 bridging group; Y is a hydrophilic function selected from the group consisting of those of formulae:

wherein X a is H, a monovalent metal or an ammonium group of formula —N(R′ n ) 4 ,
wherein R′ n , equal or different at each occurrence, represents a hydrogen atom or a C 1-6 hydrocarbon group;
and mixtures thereof.

5. The method of claim 4 , wherein the aqueous emul

Assignees

• Solvay Specialty Polymers It

Inventors

• Dossi Marco
• Avataneo Marco

Classifications

• C08F214/262 Primary

  with fluorinated vinyl ethers · CPC title

• C08F2/24

  with the aid of emulsifying agents · CPC title

• C08F2/38

  Polymerisation using regulators, e.g. chain terminating agents {, e.g. telomerisation} · CPC title

• C08F214/222

  with fluorinated vinyl ethers · CPC title

• C08F2500/02

  Low molecular weight, e.g. <100,000 Da. · CPC title