Perfluoroelastomer compositions for low temperature applications

• US 7,381,774 B2
• Filed: 10/25/2005
• Issued: 06/03/2008
• Est. Priority Date: 10/25/2005
• Status: Active Grant

• Current Assignee: Dupont Polymers Inc. (DuPont de Nemours, Inc.)
• Original Assignee: DuPont Performance Elastomers LLC (Corteva, Inc.)
• Inventors: Bish, Christopher John, Coughlin, Michael Cregg
• Primary Examiner(s): Mulcahy; Peter D.
• Assistant Examiner(s): HU, HENRY S
• Application Number:
  US11/257,539
• Publication Number:
  US 20070093608A1
• Time in Patent Office: 952 Days
• Field of Search: 525/326.2, 525/326.3, 525/187, 525/186, 525/387, 524/208, 526/247, 526/250
• US Class Current: 525/326.2
• CPC Class Codes: C08G 2650/48 containing fluorine, e.g. perfluropolyethers
• CPC Class Codes: C08G 65/007 containing fluorine
• CPC Class Codes: C08L 2666/04 Macromolecular compounds according to groups C08L7/00 - C08L49/00, or C08L55/00 - C08L57/00; Derivatives thereof
• CPC Class Codes: C08L 2666/14 Macromolecular compounds according to C08L59/00 - C08L87/00; Derivatives thereof
• CPC Class Codes: C08L 27/18 Homopolymers or copolymers or tetrafluoroethene
• CPC Class Codes: C08L 71/00 Compositions of polyethers obtained by reactions forming an ether link in the main chain of polyacetals C08L59/00; of epoxy resins C08L63/00; of polythioether-ethers C08L81/02; of polyether-sulfones C08L81/06; Compositions of derivatives of such polymers

Abstract

Perfluoroelastomers that contain high levels (i.e. about 40 mole percent or more) of perfluoro(alkyl vinyl ether) copolymerized units can form stable blends with higher levels of perfluoropolyethers than can perfluoroelastomers that contain lower levels of perfluoro(alkyl vinyl ether) units. Thus, the former blends have better low temperature properties than the latter.

Claims

1. A perfluoroelastomer composition comprising

A) a perfluoroelastomer comprising copolymerized units of i) 40 to 55 mole percent perfluoro(alkyl vinyl ether), ii) 0.1 to 3 mole percent of a cure site monomer and the remaining copolymerized units being of iii) tetrafluoroethylene so that total mole percent is 100;

and

B) 25 to 50 phr of a perfluoropolyether selected from the group consisting of i) CF₃—

(O—

CF₂CF₂)_n(OCF₂)_m—

OCF₃;

ii) F—

(CF₂CF₂CF₂—

O)_p—

CF₃; and

iii) F—

(CF(CF₃)—

CF₂—

O)_q—

CF₂CF₃ wherein n, m, p and q are integers between 1 and 180.

2. A perfluoroelastomer composition of claim 1 wherein said perfluoroelastomer contains 43 to 50 mole percent copolymerized units of perfluoro(methyl vinyl ether).

3. A perfluoroelastomer composition of claim 1 wherein said cure site monomer is selected from the group consisting of fluorovinyl ethers having a pendant nitrite group and fluoroolefins having a pendant nitrile group.

4. A perfluoroelastomer composition of claim 1 further comprising C) a curative.

5. A perfluoroelastomer composition of claim 4 wherein said curative is selected from the group consisting of organic peroxides, bis(aminophenols), organotin compounds and compounds that decompose at curing temperatures to release ammonia.

6. A cured article formed from a composition comprising the composition of claim 4.

7. A perfluoroelastomer composition of claim 1 wherein said perfluoropolyether is CF₃—

(O—

CF₂CF₂)_n(OCF₂)_m—

OCF₃ wherein m+n=40-180 and n/m=0.5-2.

8. A perfluoroelastomer composition of claim 1 wherein said perfluoropolyether is F—

(CF₂CF₂CF₂—

O)_p—

CF₃ wherein p is an integer between 10 and 60.

9. A perfluoroelastomer composition of claim 1 wherein said perfluoropolyether is F—

(CF(CF₃)—

CF₂—

O)_q—

CF₂CF₃ wherein q is an integer between 10 and 60.

10. A perfluoroelastomer composition of claim 9 wherein said perfluoropolyether is F—

(CF(CF₃)—

CF₂—

O)_q—

CF₂CF₃ having a kinematic viscosity, as measured by ASTM D445, of 3500 cSt at 20°

C.