Rubber composition for tire and pneumatic tire using the same

Abstract

The present invention provides a rubber composition of a tire, in which friction on ice is improved, and a pneumatic tire using the composition for a tire tread. Specifically, the present invention relates to a rubber composition for a tire comprising 0.5 to 30 parts by weight of a filler having at least two protuberances based on 100 parts by weight of diene rubber and a pneumatic tire using the composition for a tire tread.

1 . A rubber composition for a tire comprising 0.5 to 30 parts by weight of a filler having at least two protuberances based on 100 parts by weight of diene rubber.  
     
     
         2 . The rubber composition for a tire of  claim 1 , which further comprises 0.5 to 20 parts by weight of porous natural glass.  
     
     
         3 . The rubber composition for a tire of  claim 1 , which further comprises 0.5 to 20 parts by weight of non-metal fiber having average fiber diameter of 1 to 100 μm and average fiber length of 0.1 to 5 mm.  
     
     
         4 . The rubber composition for a tire of  claim 1 , which satisfies the equation: 
         2X+Y+2Z≦30 
       when X, Y and Z respectively represent the amounts of said non-metal fiber, said filler having at least two protuberances and said porous natural glass.  
     
     
         5 . The rubber composition for a tire of  claim 1 , wherein said filler is zinc oxide whiskers.  
     
     
         6 . A pneumatic tire comprising the rubber composition for a tire of  claim 1 .  
     
     
         7 . The pneumatic tire of  claim 6 , wherein the ratio of complex elastic modulus E1 in the tread thickness direction to complex elastic modulus E2 in the tread circumferential direction of a rubber sample cut out from a tread satisfies the equation 
         1.1 ≦E 1 /E 2.