To provide a pneumatic tire that achieves high-order balance between a high spring constant and low rolling resistance.
The pneumatic tire comprises as a carcass-covering rubber a rubber composition that comprises 100 pts.wt. of a rubber component comprised of 5-60 pts.wt. of a vinyl-cis-polybutadiene rubber, obtained by (1) adjusting the water concentration in the mixture of 1,3-butadiene with an inactive organic solvent mainly composed of 4C fractions, (2) subsequently adding a catalyst for cis-1,4-polymerization to the mixture thereby causing 1,3-butadiene to cis-1,4-polymerize, and then (3) causing a 1,2-polymerization catalyst to exist in the obtained polymerization reaction mixture thereby causing 1,3-butadiene to 1,2-polymerize, and 95-40 pts.wt. of an NR, IR, SBR and/or BR, 30-80 pts.wt. of carbon black at least 40% of which has an N
COPYRIGHT: (C)2008,JPO&INPIT
Takashi Ishida
Tetsuji Koga