Inner liner rubber composition and pneumatic tire

摘要

Inner liner rubber composition for a pneumatic tire, which enables improvements in handling stability, fuel economy, elongation at break, sheet processability, air barrier properties, and compounding cost in a balanced manner. Also, pneumatic tire including inner liner formed from the rubber composition. The rubber composition includes: reclaimed butyl rubber; halogenated butyl rubber other than the reclaimed butyl rubber; at least one semi-reinforcing filler selected from finely ground bituminous coal having a specified average particle size, talc, mica, and hard clay; and carbon black having a specific N2SA and/or silica having a specific N2SA. The rubber composition has a predetermined reclaimed butyl rubber content, a predetermined combined content of the reclaimed butyl rubber and the halogenated butyl rubber, a predetermined total semi-reinforcing filler content, and a predetermined combined content of the carbon black and the silica.

主权项

1. An inner liner rubber composition, comprising:
a rubber component containing a reclaimed butyl rubber and a halogenated butyl rubber other than the reclaimed butyl rubber; at least one semi-reinforcing filler selected from the group consisting of finely ground bituminous coal having an average particle size of 50 μm or less, talc, mica, and hard clay; at least one of a carbon black having a nitrogen adsorption specific surface area of 20 to 35 m2/g and a silica having a nitrogen adsorption specific surface area of 40 to 120 m2/g; and zinc oxide,
wherein the inner liner rubber composition has a reclaimed butyl rubber content of 5 to 30 mass % and a combined content of the reclaimed butyl rubber and the halogenated butyl rubber of 70 to 100 mass %, each based on 100 mass % of the rubber component, the inner liner rubber composition has a total semi-reinforcing filler content of 3 to 45 parts by mass, a combined content of the carbon black and the silica of 20 to 60 parts by mass, and a content of zinc oxide of 0.8 to 1.8 parts by mass, each per 100 parts by mass of the rubber component.