Claims
- 1. A styrene-isoprene-butadiene rubber which is particularly valuable for use in making truck tire treads, said rubber being comprised of repeat units which are derived from about 5 weight percent to about 20 weight percent styrene, from about 7 weight percent to about 35 weight percent isoprene, and from about 55 weight percent to about 88 weight percent 1,3-butadiene, wherein the repeat units derived from styrene, isoprene and 1,3-butadiene are in essentially random order, wherein from about 25% to about 40% of the repeat units derived from the 1,3-butadiene are of the cis-microstructure, wherein from about 40% to about 60% of the repeat units derived from the 1,3-butadiene are of the trans-microstructure, wherein from about 5% to about 25% of the repeat units derived from the 1,3-butadiene are of the vinyl-microstructure, wherein from about 75% to about 90% of the repeat units derived from the isoprene are of the 1,4-microstructure, wherein from about 10% to about 25% of the repeat units derived from the isoprene are of the 3,4-microstructure, wherein the rubber has a glass transition temperature which is within the range of about -90.degree. C. to about -70.degree. C., wherein the rubber has a number average molecular weight which is within the range of about 150,000 to about 400,000, wherein the rubber has a weight average molecular weight of about 300,000 to about 800,000, and wherein the rubber has an inhomogeneity which is within the range of about 0.5 to about 1.5.
- 2. A styrene-isoprene-butadiene rubber as specified in claim 1 wherein the repeat units in the rubber are derived from about 6 weight percent to about 15 weight percent styrene, from about 10 weight percent to about 30 weight percent isoprene, and from about 60 weight percent to about 80 weight percent butadiene.
- 3. A styrene-isoprene-butadiene rubber as specified in claim 2 wherein at least 90% of the repeat units in the rubber which are derived from styrene are in blocks of two or less repeat units.
- 4. A styrene-isoprene-butadiene rubber as specified in claim 3 wherein from about 30 percent to about 35 percent of the repeat units derived from the 1,3-butadiene are of the cis-microstructure, wherein from about 45 to about 55 percent of the repeat units derived from the 1,3-butadiene are of the trans-microstructure, wherein from about 15 percent to about 20 percent of the repeat units derived from the 1,3-butadiene are of the vinyl-microstructure, wherein from about 80 percent to about 85 percent of the repeat units which are derived from the isoprene are of the 1,4-microstructure, and wherein from about 15 percent to about 20 percent of the repeat units derived from the isoprene are of the 3,4-microstructure.
- 5. A styrene-isoprene-butadiene rubber as specified in claim 4 wherein said rubber has a number average molecular weight which is within the range of about 250,000 to about 300,000 and wherein said rubber has a weight average molecular weight which is within the range of about 500,000 to about 600,000.
- 6. A styrene-isoprene-butadiene rubber as specified in claim 5 wherein said rubber has an inhomogeneity which is within the range of about 0.8 to about 1.2.
- 7. A styrene-isoprene-butadiene rubber as specified in claim 6 wherein the repeat units in said rubber are derived from about 8 weight percent to about 12 weight percent styrene, from about 15 weight percent to about 30 weight percent isoprene, and from about 60 weight percent to about 75 weight percent 1,3-butadiene.
- 8. A styrene-isoprene-butadiene rubber as specified in claim 7 wherein said rubber has a glass transition temperature which is within the range of about -85.degree. C. to about -75.degree. C.
- 9. A pneumatic truck tire having an outer circumferential tread wherein said tread is a sulfur cured rubber composition comprised of, based on 100 parts by weight of rubber, (a) from about 45 to about 75 parts of a styrene-isoprene-butadiene rubber comprised of repeat units which are derived from about 5 weight percent to about 20 weight percent styrene, from about 7 weight percent to about 35 weight percent isoprene, and from about 55 weight percent to about 88 weight percent 1,3-butadiene, wherein the repeat units derived from styrene, isoprene, and 1,3-butadiene are in essentially random order, wherein from about 25% to about 40% of the repeat units derived from the 1,3-butadiene are of the cis-microstructure, wherein from about 40% to about 60% of the repeat units derived from the 1,3-butadiene are of the trans-microstructure, wherein from about 5% to about 25% of the repeat units derived from the 1,3-butadiene are of the vinyl-microstructure, wherein from about 75% to about 90% of the repeat units derived from the isoprene are of the 1,4-microstructure, wherein from about 10% to about 25% of the repeat units derived from the isoprene are of the 3,4-microstructure, wherein the rubber has a glass transition temperature which is within the range of about -90.degree. C. to about -70.degree. C., wherein the rubber has a number average molecular weight which is within the range of 150,000 to 400,000, wherein the rubber has a weight average molecular weight of 300,000 to 800,000, and wherein the rubber has an inhomogeneity which is within the range of 0.5 to 1.5; and (b) from about 25 to about 55 parts of natural rubber.
- 10. A pneumatic truck tire as specified in claim 9 which is comprised of (a) from about 55 parts to about 65 parts of the styrene-isoprene-butadiene rubber and (b) from about 35 parts to about 45 parts of natural rubber.
- 11. A pneumatic truck tire having an outer circumferential tread wherein said tread is a sulfur cured rubber composition comprised of, based on 100 parts by weight of rubber, (a) from about 50 to about 70 parts of a styrene-isoprene-butadiene rubber comprised of repeat units which are derived from about 5 weight percent to about 20 weight percent styrene, from about 7 weight percent to about 35 weight percent isoprene, and from about 55 weight percent to about 88 weight percent 1,3-butadiene, wherein the repeat units derived from styrene, isoprene, and 1,3-butadiene are in essentially random order, wherein from about 25% to about 40% of the repeat units derived from the 1,3-butadiene are of the cis-microstructure, wherein from about 40% to about 60% of the repeat units derived from the 1,3-butadiene are of the trans-microstructure, wherein from about 5% to about 25% of the repeat units derived from the 1,3-butadiene are of the vinyl-microstructure, wherein from about 75% to about 90% of the repeat units derived from the isoprene are of the 1,4-microstructure, wherein from about 10% to about 25% of the repeat units derived from the isoprene are of the 3,4-microstructure, wherein the rubber has a glass transition temperature which is within the range of about -90.degree. C. to about -70.degree. C., wherein the rubber has a number average molecular weight which is within the range of 150,000 to 400,000, wherein the rubber has a weight average molecular weight of 300,000 to 800,000, and wherein the rubber has an inhomogeneity which is within the range of 0.5 to 1.5; and (b) from about 15 to about 45 parts of natural rubber; and (c) from about 2 to about 20 parts of high cis-1,4-polybutadiene.
- 12. A pneumatic truck tire as specified in claim 11 wherein said rubber composition is comprised of (a) from about 55 parts to about 65 parts of the styrene-isoprene-butadiene rubber, (b) from about 25 parts to about 40 parts of natural rubber, and (c) from about 5 parts to about 15 parts of high cis 1,4-polybutadiene.
Parent Case Info
This is a Divisional of U.S. application Ser. No. 07/944,669, filed on Sep. 14, 1992, now U.S. Pat. No. 5,272,220.
US Referenced Citations (8)
Divisions (1)
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Number |
Date |
Country |
Parent |
944669 |
Sep 1992 |
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