Steel wire and steel cord for the reinforcing rubber article, and tire

Abstract

This invention relates to steel wires and steel cords used as a reinforcement for rubber articles such as pneumatic tire, industrial belt and the like, particularly steel wires and steel cords having an excellent adhesion property to rubber, in which an amount of phosphorus included as an oxide in a surface layer region from a brass plated surface applied to a circumferential face of a wire up to a depth of 5 nm in a radial direction of the wire is controlled to not more than 1.5 atomic %, whereby an excellent adhesion property between steel cord and coating rubber can be provided even when an adhesion promoter conventionally added in a coating rubber composition for the steel cord is reduced or is not added.

1 . A steel wire for the reinforcement of rubber articles formed by subjecting a peripheral face of a wire to a brass plating, characterized in that an amount of phosphorus included as an oxide in a surface layer region from a surface of the brass plating up to a depth of 5 nm in a radial direction of the wire is controlled to not more than 1.5 atomic %.  
     
     
         2 . A steel wire for the reinforcement of rubber articles according to  claim 1 , wherein a ratio of copper to a total amount of copper and zinc in the surface layer region is 50-80 atomic %.  
     
     
         3 . A steel wire for the reinforcement of rubber articles according to  claim 2 , wherein a copper content in the brass plated layer is uniform in the radial direction of the wire.  
     
     
         4 . A steel wire for the reinforcement of rubber articles according to  claim 1 , wherein when a distribution of a ratio of atomicity of copper to total atomicity of copper, zinc, carbon and oxygen at a region from the surface of the brass plating up to a depth of 6 nm in the radial direction of the wire is approximated to quadratic function, a parameter in a variable term of second degree of the quadratic function is not more than −0.2 (atomic %/(nm) 2 ).  
     
     
         5 . A steel wire for the reinforcement of rubber articles according to any one of  claims 1  to  4 , wherein an average thickness of the brass plated layer is 0.13-0.35 μm.  
     
     
         6 . A steel wire for the reinforcement of rubber articles according to any one of  claims 1  to  5 , wherein a ratio of copper to sum of copper and zinc in the brass plated layer is 60-70% by weight, and a ratio of copper to sum of copper and zinc in the surface layer region is 15-45 atomic %.  
     
     
         7 . A steel wire for the reinforcement of rubber articles according to any one of  claims 1  to  6 , wherein a diameter of the wire is not more than 0.40 mm.  
     
     
         8 . A steel cord for the reinforcement of rubber articles, characterized by twisting a plurality of wires as claimed in any one of  claims 1  to  7 .  
     
     
         9 . A tire comprising a carcass toroidally extending between a pair of bead portions as a skeleton and a belt disposed outside the carcass in a radial direction, characterized in that the steel wire as claimed in any one of  claims 1  to  7  or the steel cord as claimed in  claim 8  is used in either the carcass or the belt or both.