Crosslinkable composition and molded article made of same

Abstract

The present invention provides a crosslinkable composition being capable of providing a molded article and a sealing material for an oxygen sensor which have excellent long-term heat resistance and satisfactory compression set. Also there is provided a molded article and a sealing material for an oxygen sensor which have excellent long-term heat resistance and satisfactory compression set. The crosslinkable composition comprises (A) a compound having at least one specific crosslinkable reaction group and (B) a nonperfluoro fluorine-containing elastomer being crosslinkable with the compound (A).

1 . A crosslinkable composition comprising:
 (A) a compound having at least one reaction group selected from the group consisting of a crosslinkable reaction group represented by the general formula (1):   
     
       
         
         
             
             
         
       
       wherein X 1 s are the same or different and each is hydrogen atom or a monovalent organic group; 
       R 1  is —OR 3  or —SR 3 , and R 3  is hydrogen atom or a monovalent organic group; R 2  is hydrogen atom, —OR 3  or —SR 3 , and R 3  is as defined above, 
       a crosslinkable reaction group represented by the general formula (2): 
     
     
       
         
         
             
             
         
       
       wherein R 4 s are the same or different and each is hydrogen atom or cyano group and a crosslinkable reaction group represented by the general formula (3): 
     
     
       
         
         
             
             
         
       
       wherein X 2 s are the same or different and each is hydrogen atom or monovalent organic group; Z −  is an anion derived from an acid; Y 1  is —OH, —SH or —N + X 2   2 H.Z −  (X 2  and Z −  are as defined above), 
       a compound represented by the general formula (4): 
     
     
       
         
         
             
             
         
       
       wherein X 1  and R 1  are as defined above, 
       a compound represented by the general formula (5): 
     
     
       
         
         
             
             
         
       
       wherein R 4  is as defined above, or 
       a compound represented by the general formula (6): 
     
     
       
         
         
             
             
         
       
       wherein X 2 , Z −  and Y 1  are as defined above, and 
       (B) a nonperfluoro fluorine-containing elastomer being capable of crosslinking reaction with the compound (A). 
     
   
   
       2 . The crosslinkable composition of  claim 1 , wherein the compound (A) is a compound having a symmetric structure. 
   
   
       3 . The crosslinkable composition of  claim 1 , wherein the nonperfluoro fluorine-containing elastomer (B) has, at least at either its trunk chain or an end of its side chain, at least one kind of crosslinkable functional group selected from the group consisting of cyano group, a carboxyl group, an alkoxycarbonyl group and an acid halide group as a cure site being capable of crosslinking reaction with the compound (A). 
   
   
       4 . The crosslinkable composition of  claim 3 , wherein the nonperfluoro fluorine-containing elastomer (B) has cyano group as a cure site at least at either its trunk chain or an end of its side chain. 
   
   
       5 . The crosslinkable composition of  claim 3 , wherein the nonperfluoro fluorine-containing elastomer (B) has a crosslinkable functional group as a cure site at an end of its side chain. 
   
   
       6 . The crosslinkable composition of  claim 1 , wherein the nonperfluoro fluorine-containing elastomer (B) has a vinylidene fluoride unit and/or a tetrafluoroethylene unit and/or a hexafluoropropylene unit and at least one kind of different monomer unit. 
   
   
       7 . The crosslinkable composition of  claim 1 , wherein the nonperfluoro fluorine-containing elastomer (B) is
 (1) vinylidene fluoride/hexafluoropropylene copolymer,   (2) vinylidene fluoride/tetrafluoroethylene/hexafluoropropylene copolymer,   (3) tetrafluoroethylene/propylene copolymer,   (4) hexafluoropropylene/ethylene copolymer,   (5) tetrafluoroethylene/vinylidene fluoride/fluoro(alkyl vinyl ether) copolymer, or   (6) chlorotrifluoroethylene/vinylidene fluoride/fluoro(alkyl vinyl ether) copolymer.   
   
   
       8 . The crosslinkable composition of  claim 1 , wherein the nonperfluoro fluorine-containing elastomer (B) has at least one kind of crosslinkable functional group selected from the group consisting of cyano group, a carboxyl group, an alkoxycarbonyl group and an acid halide group in its side chain in an amount of 0.1 to 5% by mole. 
   
   
       9 . A molded article obtained by crosslinking the crosslinkable composition of  claim 1 . 
   
   
       10 . A sealing material for an oxygen sensor obtained by crosslinking the crosslinkable composition of  claim 1 . 
   
   
       11 . A method of producing a molded article comprising steps of subjecting the crosslinkable composition of  claim 1  to press crosslinking at 180° to 250° C. and oven crosslinking at 250° to 320° C.