PNEUMATIC TYRE HAVING A TOP AREA WITH A WATER BARRIER LAYER

摘要

The invention relates to a radial tyre (1) for an automobile, that comprises: a top (2) over which is arranged a tread (3) including at least one radially outer portion (3a) to be brought in contact with the road; two non-extensible beads (4), two flanges (5) connecting the beads (4) to the tread (3), a carcass armature (6) extending in the two flanges (5) and anchored in the beads (4); the top (2) being reinforced by a top armature or belt (7) arranged circumferentially between the carcass armature (6) and the tread (3); a radially inner elastomer layer (3b, 8) or sub-layer having a formulation different from that of the radially outer elastomer layer (3a), said sub-layer being provided between the radially outer layer (3a) of the tread (3) and the belt (7); characterised in that said sub-layer includes from 50 to 100 pce of a styrene- and butadiene-containing copolymer, preferably a SBR having in particular a Tg higher than -40°C, a reinforcing filler and between 10 and 150 pce of a lamellar filler. The elastomer sub-layer has excellent water-barrier properties, thereby imparting to the tyre and the belt thereof a higher protection against water ingression risks through the tread.