| 摘要 |
<p>The invention relates to a pneumatic tire having a rubber tread comprising an outer tread cap layer (3) having an outer running surface (4) and an underlying tread base layer (5). The tread cap layer (3) comprises two primary tread cap zones (12) and one central tread cap zone (11). The central tread cap zone (11) is positioned between the primary tread cap zones (12) and spans at least 14 percent of the total outer running surface (4) of the tread cap layer (3). The primary tread cap zones (12) collectively span at least 50 percent of the total outer running surface (4) of the tread cap layer (3). The central tread cap zone (11) comprises an emulsion or solution polymerized styrene-butadiene rubber with a styrene content of from 20 to 40 percent by weight and a Tg of from -55ºC to -20ºC, a polybutadiene with a cis-1,4 content of at least 90 percent, a number average molecular weight (Mn) of greater than 175,000 and a heterogeneity index (Mw/Mn) of less than 2.5, and silica. The primary tread cap zones (12) comprise a solution polymerized styrene-butadiene rubber functionalized with an alkoxysilane group and at least one functional group selected from the group consisting of primary amines and thiols, a polybutadiene having a microstructure comprising 96 to 99 percent cis-1,4-isomeric units, 0.1 to 1 percent trans-1,4-isomeric units and from 1 to 3 percent vinyl 1,2-isomeric units, a number average molecular weight (Mn) in a range of from 75,000 to 150,000 and a heterogeneity index (Mw/Mn) in a range of from 3/1 to 5/1, and silica.</p> |
