Lubricating rubber composition

Abstract

A rubber composition made of a diene rubber having such excellent properties as heat resistance and mechanical strength and organopolysiloxane or fluoropolymer as a lubricating substance. The lubricating substance may contain isocyanate or cyanate groups, which will react with the hydroxy groups which exist on the surface of a filler usually applied to the diene rubber, thus securely keeping the lubricating substance in the molecular structure of the composition. A liquid diene polymer containing hydroxy groups and having a good compatibility with the diene rubber may be further added to the composition so that its hydroxy groups will react with the isocyanate or cyanate groups in the lubricating substance. The liquid diene polymer may contain epoxy groups instead of hydroxy groups, whereas the lubricating substance containing such functional groups as amino, carboxyl, hydroxy or mercapto groups so that the exoxy groups in the former and the functional groups in the latter will react with each other. The composition may further contain an isocyanate compound containing isocyanate groups, with the liquid diene polymer containing hydroxy groups. In this arrangement, the hydroxy groups in the liquid diene polymer will be replaced with the isocyanate groups, which in turn will react with the functional groups in the lubricating substance.

What is claimed is: 
     
       1. A lubricating rubber composition comprising: a diene rubber; and   a fluoropolymer having at least one group selected from the group consisting of isocyanate group and cyanate group wherein said fluoropolymer is present in 3-100 parts by weight per 100 parts by weight of diene rubber.   
     
     
       2. A lubricating rubber composition as claimed in claim 1, further comprising a liquid diene polymer having a hydroxy group wherein the sum of contents of said liquid diene polymer and said fluoropolymer is 5 to 100 parts by weight per 100 parts by weight of the diene rubber. 
     
     
       3. A lubricating rubber composition comprising: a diene rubber;   a liquid diene polymer having a unit having an epoxy group; and   a fluoropolymer having a unit having at least one group selected from the group consisting of amino, carboxyl, hydroxy and mercapto groups wherein said fluoropolymer is present in 3-100 parts by weight per 100 parts by weight of diene rubber and the sum of contents of said liquid diene polymer and said fluoropolymer is 5 to 100 parts by weight per 100 parts by weight of the diene rubber.   
     
     
       4. A lubricating rubber composition as claimed in claim 3, wherein said liquid diene polymer is a polymer prepared by polymerizing or co-polymerizing a diene monomer, having a molecular weight of 500-50000 and having said epoxy group at end thereof, having an epoxy equivalent amount of 100-50000, and being in a liquid form at normal temperature. 
     
     
       5. A lubricating rubber composition as claimed in claim 3, wherein said fluoropolymer is prepared by adding at least one selected from the group consisting of amino, carboxyl, hydroxy and mercapto groups into a polyfluoroalkyl. 
     
     
       6. A lubricating rubber composition as claimed in claim 3, wherein said fluoropolymer is prepared by adding at least one selected from the group consisting of amino, carboxyl hydroxy and mercapto groups into a polyfluoroether. 
     
     
       7. A lubricating rubber composition as claimed in claim 3, wherein the sum of contents of said liquid diene polymer and fluoropolymer is 5 to 10 parts by weight with respect to 100 parts by weight of said diene rubber 
     
     
       8. A lubricating rubber composition comprising: a diene rubber;   a liquid diene polymer having at least two units each having a hydoxy group in one molecule;   an isocyanate compound having at least two units each having an isocyanate group in one molecule; and   a fluoropolymer having a unit containing at least one group selected from the group consisting of amino, carboxyl, hydroxy and mercapto groups wherein said fluoropolymer is present in 3-100 parts by weight per 100 parts by weight of diene rubber and the sum of contents of said liquid diene polymer and said fluoropolymer is 5 to 100 parts by weight per 100 parts by weight of the diene rubber.