Pneumatic tire

Abstract

A pneumatic tire includes an inner liner disposed on an inner side of the tire. The inner liner is composed of a polymer sheet made of an elastomer composition containing a SIBS modified copolymer obtained by modifying a styrene block portion of a styrene-isobutylene-styrene triblock copolymer with acid chloride having an unsaturated bond. In the inner liner, a ratio (Gs/Gb) between an average thickness Gb in a bead region Rb extending from a tire largest width position to a bead toe and an average thickness Gs in a buttress region Rs extending from the tire largest width position to a corresponding position Lu at a belt layer end is 0.30 to 0.75.

1 . A pneumatic tire comprising an inner liner disposed on an inner side of the tire,
 said inner liner being composed of a polymer sheet made of an elastomer composition containing a SIBS modified copolymer obtained by modifying a styrene block portion of a styrene-isobutylene-styrene triblock copolymer with acid chloride having an unsaturated bond, and   in said inner liner, a ratio (Gs/Gb) between an average thickness Gb in a bead region Rb extending from a tire largest width position to a bead toe and an average thickness Gs in a buttress region Rs extending from the tire largest width position to a corresponding position Lu at a belt layer end being 0.30 to 0.75.   
     
     
         2 . The pneumatic tire according to  claim 1 , wherein said acid chloride is methacrylic acid chloride. 
     
     
         3 . The pneumatic tire according to  claim 1 , wherein said styrene-isobutylene-styrene triblock copolymer contains a styrene component at a content of 10 percent by mass to 30 percent by mass, and has a weight average molecular weight ranging from 50,000 to 400,000. 
     
     
         4 . The pneumatic tire according to  claim 1 , wherein said SIBS modified copolymer is contained by more than or equal to 10 percent by mass and less than or equal to 100 percent by mass in an elastomer component. 
     
     
         5 . The pneumatic tire according to  claim 1 , wherein an elastomer component of said elastomer composition is a mixture of the styrene-isobutylene-styrene triblock copolymer and the SIBS modified copolymer. 
     
     
         6 . The pneumatic tire according to  claim 1 , wherein the elastomer composition has blended therein a tackifier by 0.1 part by mass to 100 parts by mass relative to 100 parts by mass of an elastomer component. 
     
     
         7 . The pneumatic tire according to  claim 1 , wherein the average thickness Gs in the buttress region of said inner liner is 0.05 mm to 0.40 mm.