PNEUMATIC TIRE

Abstract

The present invention is directed to a pneumatic tire having a tread comprising a vulcanizable rubber composition comprising, based on 100 parts by weight of elastomer (phr): (A) from about 20 to about 100 phr of a solution polymerized functionalized isoprene-butadiene rubber having a glass transition temperature (Tg) ranging from −100° C. to −50° C., (B) from 0 to about 40 phr of a polybutadiene, (C) from 0 to 20 phr of a process oil, (D) from 40 to 80 phr of a resin having a Tg greater than 30° C., and (E) from 100 to 180 phr of silica.

Claims

1. A pneumatic tire having a tread comprising a vulcanizable rubber composition comprising, based on 100 parts by weight of elastomer (phr): (A) from about 20 to about 100 phr of a solution polymerized functionalized isoprene-butadiene rubber having a glass transition temperature (Tg) ranging from −100° C. to −50 ° C.; (B) from 0 to about 40 phr of a polybutadiene; (C) from 0 to 20 phr of a process oil; (D) from 40 to 80 phr of a resin having a Tg greater than 30° C.; and (E) from 100 to 180 phr of silica.

2. The pneumatic tire of claim 1, wherein the functionalized isoprene-butadiene rubber is functionalized with a silyl group.

3. The pneumatic tire of claim 1, wherein the functionalized isoprene-butadiene rubber is functionalized with a silyl group substituted with at least one member of the group consisting of alkoxy groups, alkyl groups, and alkylamino groups.

4. The pneumatic tire of claim 1, wherein the functionalized isoprene-butadiene rubber is functionalized with a silyl group substituted with an alkoxy group selected from the group consisting of methoxy and ethoxy.

5. The pneumatic tire of claim 1, wherein the functionalized isoprene-butadiene rubber is functionalized with a silyl group substituted with an alkyl group selected from the group consisting of methyl, ethyl, and propyl.

6. The pneumatic tire of claim 1, wherein the functionalized isoprene-butadiene rubber is functionalized with a silyl group substituted with an alkylamino group selected from the group consisting of diethylamino and dimethylamino.

7. The pneumatic tire of claim 1, wherein the resin is a C5/C9 resin comprising 50-90% (by weight) piperylenes, 0-5% isoprene, 10-30% amylenes, 0-5% cyclics, 0-10% styrenics, and 0-10% indenics.

8. The pneumatic tire of claim 1, wherein the resin is a C5/C9 resin comprising 50-90% (by weight) piperylenes, 0-5% isoprene, 10-30% amylenes, 2-5% cyclics, 4-10% styrenics, and 4-10% indenics.

9. The pneumatic tire of claim 1, wherein the resin is a C5/C9 resin and has an aromatic hydrogen content less than 25 mole percent.

10. The pneumatic tire of claim 1, wherein the resin is a C5/C9 resin and has an aromatic hydrogen content between 3 and 15 mole percent.

11. The pneumatic tire of claim 1, wherein the solution polymerized isoprene-butadiene rubber is functionalized with an alkoxysilane group and optionally an amino group.

12. The pneumatic tire of claim 1, wherein the oil is selected from the group consisting of aromatic, paraffinic, naphthenic, MES, TDAE, heavy naphthenic oils, and vegetable oils.

13. The pneumatic tire of claim 1, wherein the amount of the functionalized isoprene-butadiene rubber ranges from 70 to 95 phr.

14. The pneumatic tire of claim 1, wherein the amount of the polybutadiene ranges from 5 to 30 phr.

15. The pneumatic tire of claim 1, wherein the amount of the oil ranges from 4 to 15 phr.

16. The pneumatic tire of claim 1, wherein the amount of the resin ranges from 50 to 70 phr.

17. The pneumatic tire of claim 1, wherein the polybutadiene has a cis 1,4 content greater than 95 percent and a Tg ranging from −80 to −110° C.

Description

EXAMPLE

[0092] This example illustrates the advantage of a rubber composition according to the invention. Rubber compounds were mixed according to the formulation shown in Table 1, with amounts given in phr. The compounds were cured and tested for physical properties as shown in Table 2. The inventive rubber composition comprised of the functionalized IBR demonstrates simultaneous improvements in predicted wet, RR and Wear properties of the tread compound.

TABLE-US-00001 TABLE 1 Composition C1 E1 E2 Styrene-Butadiene Rubber .sup.1 40 0 0 Isoprene-Butadiene Rubber.sup.2 0 90 0 Isoprene-Butadiene Rubber, functionalized.sup.3 0 0 90 Polybutadiene .sup.4 60 10 10 Silica.sup.5 140 140 140 Oil 5 5 5 Silane .sup.6 8.8 8.8 8.8 Traction Resin .sup.7 62 62 62 .sup.1 Solution polymerized SBR with styrene content of 15% and 1,2-vinyl content of 30%, Tg = −60° C. obtained from Trinseo as SLR3402. .sup.2Solution polymerized IBR, 30/70 wt/wt isoprene/butadiene, Tg −80° C. from Goodyear Chemical. .sup.3Solution polymerized IBR, 30/70 wt/wt isoprene/butadiene, Tg −80° C., functionalized with substituted silyl groups, from Goodyear Chemical. .sup.4 High cis polybutadiene, obtained as Budene 1223 from The Goodyear Tire & Rubber Company. .sup.5Hi-Sil 315G-D precipitated silica from PPG with a CTAB surface area of 125 m.sup.2/g .sup.6 TESPD type silane coupling agent. .sup.7 Petroleum traction resin made of C5 and C9 monomers, Tg = +38° C., with an aromatic hydrogen content of around 12 mole %, obtained as Oppera PR373 from ExxonMobil.

TABLE-US-00002 TABLE 2 Composition C1 E1 E2 Compound Tg, ° C. −43 −45 −44 Din Abrasion .sup.1 (Relative volume loss in mm.sup.3, 114 105 103 lower is better) Wet grip property.sup.2 Rebound at −10° C. 9.9 9.3 9.0 (%, lower is better) Low temperature property.sup.3 E′ at 0.25% strain, −30° 92.0 82.0 77.7 C. (MPa) RR Property.sup.2 Rebound at 100° C. 45.5 45.8 49.9 (%, higher is better) .sup.1 Data according to DIN 53516 abrasion resistance test procedure using a Zwick drum abrasion unit, model 6102 with 2.5 Newtons force. DIN standards are German test standards. .sup.2Rebound is a measure of hysteresis of the compound when subject to loading, as measured by ASTM D1054. Generally, the lower the measured rebound at −10° C., the better the wet grip property. Generally, the higher the measured rebound at 100° C., the lower the rolling resistance. .sup.3The E′ modulus at low temperatures can be readily be determined by means of a GABO Eplexor tester. The test specimen is subjected to 0.25% sinusoidal deformation at 1 Hz and the temperature is varied. The test method is understood to be similar to ISO 6721.

[0093] While certain representative embodiments and details have been shown for the purpose of illustrating the subject invention, it will be apparent to those skilled in this art that various changes and modifications can be made therein without departing from the scope of the subject invention.