Low viscosity fluoroelastomers

Patent metadata

Field	Value
Publication number	US-9458272-B2
Application number	US-201113993782-A
Country	US
Kind code	B2
Filing date	Dec 13, 2011
Priority date	Dec 20, 2010
Publication date	Oct 4, 2016
Grant date	Oct 4, 2016

Abstract

The invention pertains to a low viscosity curable (per)fluoroelastomer [fluoroelastomer (A)] having a number-averaged molecular weight of 3 000 to 45 000, said (per)fluoroelastomer comprising at least 1% moles, with respect to the total moles of recurring units, of recurring units derived from at least one (per)fluoromethoxyalkylvinylether of formula (I):

CFX′═CX″OCF 2 OR f   formula (I)

wherein X′ and X″, equal to or different from each other, are independently H or F; and R f is selected from the group consisting of 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 ethereal oxygen atoms [monomer (M)].

First claim

The invention claimed is:

1. A low viscosity curable fluoroelastomer or (per)fluoroelastomer [fluoroelastomer (A)] having a number-averaged molecular weight of 3,000 to 45,000, said fluoroelastomer (A) comprising:
at least 1% moles, with respect to the total moles of recurring units, of recurring units derived from at least one (per)fluoromethoxyalkylvinylether of formula (I):
CFX′═CX″OCF 2 OR f   formula (I)

wherein X′ and X″, equal to or different from each other, are independently H or F; and R f is selected from the group consisting of 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 ethereal oxygen atoms [monomer (M)],
recurring units derived from vinylidene fluoride (VDF), from tetrafluoroethylene (TFE), or from a combination thereof, and optionally
recurring units derived from at least one additional (per)fluorinated monomer [comonomer (C)], wherein comonomer (C) is different from monomer (M), VDF and TFE.

2. The fluoroelastomer (A) of claim 1 , wherein monomer (M) is a perfluoromethoxyalkylvinylether of formula (I):
CF 2 ═CFOCF 2 OR′ f   formula (I)

wherein R′ f is selected from the group consisting of C 1 -C 6 perfluoroalkyls, linear or branched; C 5 -C 6 cyclic perfluoroalkyls; and C 2 -C 6 perfluorooxyalkyls, linear or branched, comprising from 1 to 3 catenary ethereal oxygen atoms.

3. The fluoroelastomer of claim 2 , wherein monomer (M) is selected from the group consisting of:
CF 2 ═CFOCF 2 O—CF 3 ;  (M1)

CF 2 ═CFOCF 2 O—CF 2 CF 3 ; and  (M2)

CF 2 ═CFOCF 2 O—CF 2 CF 2 OCF 3 .  (M3)

4. The fluoroelastomer (A) of claim 1 , wherein comonomer (C) is selected from the group consisting of:
C 2 -C 8 fluoro- and/or perfluoroolefins;
1,2-difluoroethylene, vinylidene fluoride (VDF) and trifluoroethylene (TrFE);
(per)fluoroalkylethylenes complying with formula CH 2 ═CH—R f0 , wherein 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 wherein R f1 is a C 1 -C 6 fluoro- or perfluoroalkyl;
hydrofluoroalkylvinylethers complying with formula CH 2 ═CFOR f1 wherein R f1 is a C 1 -C 6 fluoro- or perfluoroalkyl;
fluoro-oxyalkylvinylethers different from formula (I) and complying with formula CF 2 ═CFOX 0 , wherein X 0 is a C 1 -C 12 oxyalkyl, or a C 1 -C 12 (per)fluorooxyalkyl having one or more ether groups;
functional fluoro-alkylvinylethers complying with formula CF 2 ═CFOY 0 , wherein 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,
wherein:
if the fluoroelastomer (A) is a VDF-based copolymer, comonomer (C) is not VDF; and
if the fluoroelastomer (A) is a TFE-based copolymer, comonomer (C) is not TFE.

5. The fluoroelastomer (A) of claim 1 , comprising at least 3% moles with respect to the total moles of recurring units, of recurring units derived from said monomer (M).

6. The fluoroelastomer (A) of claim 1 , wherein the sum of recurring units derived from said monomer (M) and said comonomer (C) represents at least 10% moles, with respect to the total amount of recurring units of said fluoroelastomer (A).

7. The fluoroelastomer (A) of claim 6 , said fluoroelastomer being selected from the group consisting of VDF-based copolymers comprising, with respect to total moles of recurring units of said fluoroelastomer (A):
from 5 to 35% moles of recurring units derived from monomer (M);
from 0.5 to 35% moles of recurring units derived from at least one C 2 -C 8 perfluoroolefin;

wherein the sum of recurring units derived from said monomer (M) and from the perfluoroolefin is of at least 10% moles; and
from 90 to 30% moles of recurring units derived from said VDF.

8. The fluoroelastomer (A) of claim 1 , having a number-averaged molecular weight of at least 7,000.

9. The fluoroelastomer (A) of claim 1 , having a number-averaged molecular weight of at most 40,000.

10. The fluoroelastomer (A) of claim 1 , further comprising cure sites as pendant groups bonded to certain recurring units.

11. The fluoroelastomer (A) of claim 10 , wherein said cure-site containing recurring units are selected from the group consisting of:
(CSM-1) iodine or bromine containing monomers of formula:

wherein each of A Hf , equal to or different from each other and at each occurrence, is independently selected from F, Cl, and H; B Hf is any of F, Cl, H and OR Hf B , wherein R Hf B is a branched or straight chain alkyl radical which can be partially, substantially or completely fluorinated or chlorinated; each of W Hf equal to or different from each other and at each occurrence, is independently a covalent bond or an oxygen atom; E Hf is a divalent group having 2 to 10 carbon atom, optionally fluorinated; R Hf is a branched or straight chain alkyl radical, which can be partially, substantially or completely fluorinated; and X Hf is a halogen atom selected from the group consisting of Iodine and Bromine; which may be inserted with ether linkages; and
(CSM-2) ethylenically unsaturated compounds comprising cyanide groups, optionally fluorinated.

12. The fluoroelastomer (A) of claim 1 , further comprising iodine or bromine cure sites in an amount of 0.001 to 10% wt.

13. The fluoroelastomer (A) of claim 12 , wherein said iodine or bromine cure sites comprise pendant groups bound to the backbone of the fluoroelastomer (A) polymer chain and/or comprise terminal groups of said polymer chain.

14. The fluoroelastomer (A) of claim 12 , wherein said fluoroelastomer (A) is obtained by addition to the polymerization medium during fluoroelastomer manufacture of anyone of:
iodinated and/or brominated chain-transfer agent(s); suitable chain-chain transfer agents are typically those of formula R f (I) x (Br) y , wherein R f is a (per)fluoroalkyl or a (per)fluorochloroalkyl containing from 1 to 8 carbon atoms, while x and y are integers between 0 and 2, with 1≦x+y≦2; and
alkali metal or alkaline-earth metal iodides and/or bromides.

Assignees

• Apostolo Marco
• Comino Giovanni
• Cristini Marco
• Solvay Specialty Polymers It

Inventors

• Apostolo Marco
• Comino Giovanni
• Cristini Marco

Classifications

• C08F214/18

  Monomers containing fluorine · CPC title

• C09D129/10

  Homopolymers or copolymers of unsaturated ethers (C09D135/08 takes precedence) · CPC title

• C08F216/1408 Primary

  Monomers containing halogen · CPC title

• C08F14/18 Primary

  Monomers containing fluorine · CPC title

• C08F2/38

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