Fluororubber composition

Abstract

A fluororubber composition comprising 100 parts by weight of a peroxide-crosslinkable tetrafluoroethylene-vinylidene fluoride-hexafluoropropene ternary copolymer rubber having a fluorine content of 64 wt. % or more, (A) 5 to 90 parts by weight of carbon black having a specific surface area of 5 to 20 m 2 /g, (B) 5 to 40 parts by weight of a fine bituminous powder, (C) at least one of 1 to 20 parts by weight of hydrophilicity-imparted talc and/or 1 to 30 parts by weight of hydrophilicity-imparted clay, and (D) 0.5 to 6 parts by weight of an organic peroxide; the fluororubber composition being used as a molding material for fuel oil sealing materials to be in contact with fuel oil. The fluororubber composition provides a sealing materials having excellent metal corrosion resistance, without compounding an acid acceptor comprising a metal oxide.

1 . A fluororubber composition comprising:
 100 parts by weight of a peroxide-crosslinkable tetrafluoroethylene-vinylidene fluoride-hexafluoropropene ternary copolymer rubber having a fluorine content of 64 wt. % or more;   (A) 5 to 90 parts by weight of carbon black having a specific surface area of 5 to 20 m 2 /g;   (B) 5 to 40 parts by weight of a fine bituminous powder;   (C) 1 to 30 parts by weight of hydrophilicity-imparted talc or   1 to 30 parts by weight of hydrophilicity-imparted talc and 1 to 20 parts by weight of hydrophilicity-imparted clay; and   (D) 0.5 to 6 parts by weight of an organic peroxide;   
       the fluororubber composition being used as a molding material for fuel oil sealing materials to be in contact with fuel oil. 
     
     
         2 . The fluororubber composition according to  claim 1 , which is free from an acid acceptor comprising a metal oxide. 
     
     
         3 . The fluororubber composition according to  claim 1 , wherein the peroxide-crosslinkable ternary type copolymer rubber has a fluorine content of 67 to 69 wt. %. 
     
     
         4 . The fluororubber composition according to  claim 1 , wherein the carbon black is MT carbon black or FT carbon black. 
     
     
         5 . The fluororubber composition according to  claim 1 , wherein the fine bituminous powder is Austin black. 
     
     
         6 . The fluororubber composition according to  claim 1 , wherein the talc is imparted with hydrophilicity by surface treatment at a high temperature of 1,100° C. or more. 
     
     
         7 . The fluororubber composition according to  claim 1 , wherein the clay is imparted with hydrophilicity by surface treatment with a silane coupling agent. 
     
     
         8 . The fluororubber composition according to  claim 1 , wherein the weight ratio of carbon black as the component (A) and fine bituminous powder as the component (B) is 6 to 1/6, and the total amount of the component (A) and the component (B) is 10 to 100 parts by weight based on 100 parts by weight of ternary type copolymer rubber. 
     
     
         9 . The fluororubber composition according to  claim 1 , wherein the total amount of the (B) fine bituminous powder and the (C) at least one of hydrophilicity-imparted talc and clay is 10 to 50 parts by weight based on 100 parts by weight of ternary type copolymer rubber. 
     
     
         10 . The fluororubber composition according to  claim 1 , wherein 1 to 10 parts by weight of (E) a polyfunctional unsaturated compound is further used in combination with the (D) organic peroxide. 
     
     
         11 . A fuel oil sealing material to be in contact with fuel oil, the sealing material being obtained by crosslinking molding of the fluororubber composition according to  claim 1 . 
     
     
         12 . A fuel oil sealing material to be in contact with fuel oil, the sealing material being obtained by crosslinking molding of the fluororubber composition according to  claim 2 . 
     
     
         13 . A fuel oil sealing material to be in contact with fuel oil, the sealing material being obtained by crosslinking molding of the fluororubber composition according to  claim 10 .