| 摘要 |
<p>It is important for tire treads to exhibit good wet skid resistance, low rolling resistance, good wear characteristics and good abrasion resistance. This is often accomplished by utilizing a blend of various rubbers in making tire tread compositions. However, some of the desirable characteristics of the individual rubbers in the blend are frequently lost on mixing. The segmented elastomers of this invention offer a unique combination of desirable characteristics for utilization in making tire tread compositions. This invention more specifically discloses a rubber polymer which has an excellent combination of properties for use in making tire treads which is comprised of: (a) a first segment which is comprised of repeat units which are derived from isoprene having a microstructure wherein there are from about 75% to about 98% 1,4-linkages and from about 2% to about 25% 3,4-linkages and wherein the first segment has a number average molecular weight which is within the range of about 25,000 to about 350,000; and (b) a second segment which is comprised of repeat units which are derived from 30 to 95 weight percent 1,3-butadiene and from 5 to 70 weight percent styrene, wherein the sum of (1) the product of 1.7 and the weight percent of styrene in the second segment and (2) the percentage of 1,2-butadiene linkages in the second segment is within the range of about 50% to about 92%, and wherein the second segment has a number average molecular weight which is within the range of about 50,000 to about 350,000.</p> |
