Peroxide curable fluoroelastomer compositions and articles made therefrom

Abstract

Peroxide curable fluoroelastomer compositions and articles made therefrom are disclosed. The compositions contain 5 to 45 weight percent, based on total weight of all fluoroelastomers present in the composition, of a blend of dynamically cured fluoroelastomer particles in an uncured fluoroelastomer. The compositions are unfilled, but have tensile properties adequate for many end use applications and are particularly useful as seals in semiconductor manufacturing equipment.

1 . A curable fluoroelastomer composition comprising:
 A) 55 to 95 weight percent, based on total weight of all fluoroelastomers in said composition, of a first curable fluoroelastomer comprising copolymerized units of i) vinylidene fluoride and ii) at least one other fluoromonomer, said first fluoroelastomer having cure sites selected from the group consisting of iodine atoms, bromine atoms, and the combination of iodine and bromine atoms;   B) 5 to 45 weight percent, based on total weight of all fluoroelastomers in said composition, of a blend comprising i) 55 to 95 weight percent, based on total weight of said blend, of cured particles of a second fluoroelastomer comprising copolymerized units of a) vinylidene fluoride and b) at least one other fluoromonomer, said second fluoroelastomer having cure sites selected from the group consisting of iodine atoms, bromine atoms, and the combination of iodine and bromine atoms; and ii) 5 to 45 weight percent, based on total weight of said blend, of an uncured third fluoroelastomer comprising copolymerized units of a) vinylidene fluoride and b) at least one other fluoromonomer, said third fluoroelastomer having no bromine or iodine cure sites;   C) less than 1 weight percent, based on total weight of said curable composition, of filler;   D) 0.1 to 6 parts by weight organic peroxide per hundred parts by weight of said first curable fluoroelastomer; and   E) 0.1 to 10 parts by weight multifunctional unsaturated coagent per hundred parts by weight of said first curable fluoroelastomer.   
   
   
       2 . A curable fluoroelastomer composition of  claim 1  wherein said first fluoroelastomer comprises copolymerized units selected from the groups consisting of i) vinylidene fluoride, hexafluoropropylene and optionally tetrafluoroethylene, and ii) vinylidene fluoride, perfluoro(methyl vinyl ether) and tetrafluoroethylene. 
   
   
       3 . A curable fluoroelastomer composition of  claim 2  wherein said first fluoroelastomer further comprises copolymerized units of a cure site monomer selected from the group consisting of iodine-containing cure site monomers, bromine-containing cure site monomers, and mixtures thereof. 
   
   
       4 . A curable fluoroelastomer composition of  claim 2  wherein said first fluoroelastomer further comprises cure sites selected from the group consisting of iodine-containing endgroups and bromine-containing endgroups. 
   
   
       5 . A curable fluoroelastomer composition of  claim 1  wherein said second fluoroelastomer comprises copolymerized units selected from the groups consisting of i) vinylidene fluoride, hexafluoropropylene and optionally tetrafluoroethylene, and ii) vinylidene fluoride, perfluoro(methyl vinyl ether) and tetrafluoroethylene. 
   
   
       6 . A curable fluoroelastomer composition of  claim 5  wherein said second fluoroelastomer further comprises copolymerized units of a cure site monomer selected from the group consisting of iodine-containing cure site monomers, bromine-containing cure site monomers, and mixtures thereof. 
   
   
       7 . A curable fluoroelastomer composition of  claim 5  wherein said second fluoroelastomer further comprises cure sites selected from the group consisting of iodine-containing endgroups and bromine-containing endgroups. 
   
   
       8 . A curable fluoroelastomer composition of  claim 1  wherein said first fluoroelastomer and said second fluoroelastomer are the same fluoroelastomer. 
   
   
       9 . A curable fluoroelastomer composition of  claim 1  wherein said third fluoroelastomer comprises copolymerized units selected from the group consisting of i) vinylidene fluoride, hexafluoropropylene and optionally tetrafluoroethylene, and ii) vinylidene fluoride, perfluoro(methyl vinyl ether) and tetrafluoroethylene. 
   
   
       10 . A cured article made from the curable fluoroelastomer composition of  claim 1 .