High purity fluoroelastomer compositions

Abstract

Fluoroelastomer compositions with minimal concentrations of extractable metal species exhibit excellent performance characteristics under conditions requiring exceptional purity.

We claim: 
     
       1. A fluoroelastomer composition substantially free of carbon black comprising: (A) at least one peroxide-curable elastomeric fluoropolymer;   (B) about 0.1-5.0 parts by weight per 100 parts by weight of (A) of an organic amine having a pKa of at least 10;   (C) about 0.1-5.0 parts by weight per 100 parts by weight of (a) of an organic peroxide;   (D) about 0.1-10.0 parts by weight per 100 parts by weight of (A) of a coagent for the organic peroxide; and   (E) at least about 1 part by weight per 100 parts by weight of (A) of a fluoropolymer filler; the composition having less than 500 parts per billion, based on the weight of (A), of metallic extractables.     
     
     
       2. A fluoroelastomer composition of claim 1 wherein the fluoropolymer filler consists essentially of a polymer of tetrafluoroethylene. 
     
     
       3. A fluoroelastomer composition of claim 1 wherein the elastomeric fluoropolymer is a perfluoropolymer. 
     
     
       4. A fluoroelastomer composition of claim 1 wherein the elastomeric fluoropolymer is a hydrogen-containing fluoropolymer. 
     
     
       5. A fluoroelastomer composition of claim 2 wherein the fluoropolymer filler consists essentially of PTFE or modified PTFE. 
     
     
       6. A fluoroelastomer composition of claim 2 wherein the fluoropolymer filler consists essentially of a melt-fabricable copolymer of TFE and PPVE. 
     
     
       7. A fluoroelastomer composition of claim 2 wherein the fluoropolymer filler consists essentially of a melt-fabricable copolymer of TFE and HFP. 
     
     
       8. A fluoroelastomer composition of claim 1 wherein the organic amine consists essentially of 1,8-bis-(dimethylamino)napthalene. 
     
     
       9. A fluoroelastomer composition of claim 1 wherein the organic amine consists essentially of octadecylamine. 
     
     
       10. A fluoroelastomer composition of claim 1 wherein the organic peroxide consists essentially of 2, 5-dimethyl-2,5-di-(t-butylperoxy) hexane. 
     
     
       11. A fluoroelastomer composition of claim 1 further comprising at least about 1 phr of plasticizer. 
     
     
       12. A fluoroelastomer composition of claim 11 wherein the placticizer consists essentially of perfluoropolyether. 
     
     
       13. A fluoroelastomer composition of claim 1 wherein the extractable metals and metal compounds are present in quantities of less than about 200 parts per billion. 
     
     
       14. A fluoroelastomer composition of claim 1 wherein the fluoroelastomer composition is substantially free of inorganic compounds. 
     
     
       15. An elastomeric seal for use in processes requiring high purity wherein the presence of metals or metal ions must be controlled, the seal comprising: (A) at least one peroxide-curable elastomeric fluoropolymer;   (B) about 0.1-5.0 parts by weight per 100 parts by weight of (A) of an organic amine having a pKa of at least 10;   (C) about 0.1-5.0 parts by weight per 100 parts by weight of (A) of an organic peroxide; and   (D) about 0.1-10.0 parts by weight per 100 parts by weight of (A) of a coagent for the organic peroxide; the composition having less than 500 parts per billion, based on the weight of (A), of metallic extractables and being substantially free of carbon black.     
     
     
       16. A fluoroelastomer composition of claim 15 further comprising at least about 1 phr fluoropolymer filler. 
     
     
       17. A fluoroelastomer composition of claim 16 wherein the fluoropolymer filler consists essentially of a polymer of tetrafluoroethylene. 
     
     
       18. A fluoroelastomer composition of claim 15 wherein the elastomeric fluoropolymer is a perfluoropolymer. 
     
     
       19. A fluoroelastomer composition of claim 15 wherein the elastomeric fluoropolymer is a hydrogen-containing fluoropolymer. 
     
     
       20. A fluoroelastomer composition of claim 16 wherein the fluoropolymer filler consists essentially of PTFE or modified PTFE. 
     
     
       21. A fluoroelastomer composition of claim 16 wherein the fluoropolymer filler consists essentially of a melt-fabricable copolymer of TFE and PPVE. 
     
     
       22. A fluoroelastomer composition of claim 16 wherein the fluoropolymer filler consists essentially of a melt-fabricable copolymer of TFE and HFP. 
     
     
       23. A fluoroelastomer composition of claim 15 wherein the organic amine consists essentially of 1,8-bis(dimethylamino)naphthalene. 
     
     
       24. A fluoroelastomer composition of claim 15 wherein the organic amine consists essentially of octadecylamine. 
     
     
       25. A fluoroelastomer composition of claim 15 wherein the organic peroxide consists essentially of 2,5-dimethyl-2,5-di-(t-butylperoxy)hexane. 
     
     
       26. A fluoroelastomer composition of claim 15 further comprising at least about 1 phr of plasticizer. 
     
     
       27. A fluoroelastomer composition of claim 26 wherein the plasticizer consists essentially of perfluoropolyether. 
     
     
       28. A fluoroelastomer composition of claim 15 wherein the metallic extractables are present in quantities of less than about 200 parts per billion based on the weight of (A). 
     
     
       29. A fluoroelastomer composition of claim 15 wherein the fluoroelastomer composition is substantially free of inorganic compounds. 
     
     
       30. A composition of any of claims 15-25 wherein the seal is cured.