Sealing members for fuel, paint compositions for the same, and manufacturing method for sealing members for fuel

Abstract

The present invention provides a sealing member for fuel which includes a fluororubber base and a sliding-treated layer coating the surface of the base. The sliding-treated layer includes a matrix made from a fluororubber, a sliding thin film formed in the surface portion of the matrix from a molten first particulate solid lubricant, and a second particulate solid lubricant dispersed in the matrix and the sliding thin film without being melted.

1 . A sealing member for fuel comprising: 
 a base comprising a fluororubber, and    a sliding-treated layer coating the surface of the base, the sliding-treated layer comprising: 
 a matrix comprising a fluororubber,  
 a sliding thin film formed in the surface portion of the matrix from a molten first particulate solid lubricant, and  
 a second particulate solid lubricant dispersed in the matrix and the sliding thin film without being melted.  
   
   
   
       2 . The sealing member for fuel according to  claim 1 , wherein the first particulate solid lubricant is a tetrafluoroethylene-hexafluoropropylene copolymer, and the second particulate solid lubricant is a polytetrafluoroethylene.  
   
   
       3 . The sealing member for fuel according to  claim 2 , wherein the second particulate solid lubricant is a polytetrafluoroethylene having a molecular weight of 300,000 or less.  
   
   
       4 . The sealing member for fuel according to  claim 1 , wherein the second particulate solid lubricant has a particle diameter of from 0.1 to 1 μm.  
   
   
       5 . The sealing member for fuel according to  claim 1 , wherein the amount of the second particulate solid lubricant is from 5 to 30 parts by mass for 100 parts by mass of the matrix, based on dry mass.  
   
   
       6 . The sealing member for fuel according to  claim 1 , wherein the sliding-treated layer has a thickness of from 3 to 40 μm.  
   
   
       7 . The sealing member for fuel according to  claim 1 , wherein the sliding-treated layer has an elongation of 60% or more.  
   
   
       8 . The sealing member for fuel according to  claim 1 , wherein the sealing member for fuel is a gasket for a fuel cap.  
   
   
       9 . A paint composition for a sealing member for fuel which coats a fluororubber base surface of the sealing member, and thereafter, is baked to form a sliding-treated layer of the sealing member, the paint composition comprising: 
 a matrix comprising a fluororubber,    a first particulate solid lubricant comprising a fluororesin which can be melted, and    a second particulate solid lubricant comprising a polytetrafluoroethylene having a molecular weight of 300,000 or less.    
   
   
       10 . The paint composition according to  claim 9 , wherein the first particulate solid lubricant is a tetrafluoroethylene-hexafluoropropylene copolymer.  
   
   
       11 . The paint composition according to  claim 9 , wherein the first particulate solid lubricant has a particle diameter of from 0.1 to 1 μm.  
   
   
       12 . The paint composition according to  claim 9 , wherein the second particulate solid lubricant has a particle diameter of from 0.1 to 1 μm.  
   
   
       13 . The paint composition according to  claim 9 , wherein the amount of the second particulate solid lubricant is from 5 to 30 parts by mass for 100 parts by mass of the matrix, based on dry mass.  
   
   
       14 . A manufacturing method for a sealing member for fuel, comprising the steps of: 
 coating a fluororubber base surface of the sealing member for fuel with a paint composition which comprises a matrix comprising a fluororubber, a first particulate solid lubricant comprising a fluororesin that can be melted, a second particulate solid lubricant comprising a polytetrafluoroethylene having a molecular weight of 300,000 or less, and    baking the paint composition after coated at a temperature which is higher than a melting point of the first particulate solid lubricant and lower than a melting point of the second particulate solid lubricant, whereby forming a sliding-treated layer coated on the base surface.    
   
   
       15 . The manufacturing method according to  claim 14 , wherein the first particulate solid lubricant is a tetrafluoroethylene-hexafluoropropylene copolymer.  
   
   
       16 . The manufacturing method according to  claim 14 , wherein the first particulate solid lubricant has a particle diameter of from 0.1 to 1 μm.  
   
   
       17 . The manufacturing method according to  claim 14 , wherein the second particulate solid lubricant has a particle diameter of from 0.1 to 1 μm.  
   
   
       18 . The manufacturing method according to  claim 14 , wherein the amount of the second particulate solid lubricant is from 5 to 30 parts by mass for 100 parts by mass of the matrix, based on dry mass.