Pneumatic tire

Abstract

Provided is a pneumatic tire having improved air permeability resistance by improving adhesive property between an inner liner and a tire component adjacent thereto, reduced rolling resistance, and improved low temperature durability. The inner liner is composed of a polymer layer stack including a first layer containing an SIBS and a second layer containing at least one of an SIS and an SIB. At least one of the first layer and the second layer is a polymer composition containing one of a C4 polymer obtained by polymerizing a monomer unit having 4 carbon atoms, a layered clay mineral with an organic compound intercalated therein and at least one kind of rubber component selected from the group consisting of a natural rubber, an isoprene rubber and a butyl rubber. The second layer is arranged to come into contact with a rubber layer of the carcass ply. The inner liner has a thickness Ge at a shoulder position Pe exceeding 100% and being less than or equal to 500% of a thickness Gc at a crown central position Pc.

1 . A pneumatic tire comprising an inner liner disposed on the tire inside relative to a carcass ply bridged between a pair of bead portions, wherein
 said inner liner is composed of a polymer layer stack including   (A) a first layer containing a styrene-isobutylene-styrene triblock copolymer, and   (B) a second layer containing a styrene-isobutylene diblock copolymer,   at least one of said first layer and said second layer is a polymer composition containing one of a C4 polymer obtained by polymerizing a monomer unit having 4 carbon atoms, a layered clay mineral with an organic compound intercalated therein and at least one kind of rubber component selected from the group consisting of a natural rubber, an isoprene rubber and a butyl rubber,   said second layer is arranged to come into contact with a rubber layer of the carcass ply, and   said inner liner has a thickness Ge at shoulder position Pe being 200% to 300% of thickness Gc at crown central position Pc, and thickness Ge at shoulder position Pe being 110% to 350% of thickness Gs at largest width position Ps.   
     
     
         2 . A pneumatic tire comprising an inner liner disposed on the tire inside relative to a carcass ply bridged between a pair of bead portions, wherein
 said inner liner is composed of a polymer layer stack including   (A) a first layer containing a styrene-isobutylene-styrene triblock copolymer and having a thickness of 0.05 mm to 0.6 mm, and   (B) a second layer containing a styrene-isobutylene diblock copolymer and having a thickness of 0.01 mm to 0.3 mm,   at least one of said first layer and said second layer has blended therein a C4 polymer obtained by polymerizing a monomer unit having 4 carbon atoms by more than or equal to 0.5 mass % and less than or equal to 40 mass %,   said second layer is arranged to come into contact with a rubber layer of the carcass ply, and   said inner liner has a thickness Ge at shoulder position Pe being 200% to 300% of thickness Gc at crown central position Pc, and thickness Ge at shoulder position Pe being 110% to 350% of thickness Gs at largest width position Ps.   
     
     
         3 . The pneumatic tire according to  claim 2 , wherein said polymer obtained by polymerizing the monomer unit having 4 carbon atoms is made of at least one of polybutene and polyisobutylene. 
     
     
         4 . The pneumatic tire according to  claim 2 , wherein said polymer obtained by polymerizing the monomer unit having 4 carbon atoms satisfies at least one of a number average molecular weight of more than or equal to 300 and less than or equal to 3,000, a weight average molecular weight of more than or equal to 700 and less than or equal to 100,000, and a viscosity average molecular weight of more than or equal to 20,000 and less than or equal to 70,000. 
     
     
         5 . A pneumatic tire comprising an inner liner disposed on the tire inside relative to a carcass ply bridged between a pair of bead portions, wherein
 said inner liner is composed of a polymer layer stack including   (A) a first layer made of a thermoplastic elastomer composition containing a styrene-isobutylene-styrene triblock copolymer by 60 mass % to 99.9 mass % in a polymer component and containing a layered clay mineral with an organic compound intercalated therein by 0.1 part by mass to 50 parts by mass relative to 100 parts by mass of the polymer component, and   (B) a second layer of a thermoplastic elastomer composition containing a styrene-isobutylene diblock copolymer,   said second layer is arranged to come into contact with the carcass ply, and   said inner liner has a thickness Ge at shoulder position Pe being 200% to 300% of thickness Gc at crown central position Pc, and thickness Ge at shoulder position Pe being 110% to 350% of thickness Gs at largest width position Ps.   
     
     
         6 . The pneumatic tire according to  claim 2 , wherein a molecular chain of said styrene-isobutylene diblock copolymer is linear, contains a styrene component at a content of 10 mass % to 35 mass %, and has a weight average molecular weight of 40,000 to 120,000.