TIRE

Abstract

The present invention is directed a tire comprising two rubber components which are co-cured together. The first rubber component comprises from 70 phr to 100 phr of a hydrogenated styrene butadiene rubber, 0 phr to 15 phr of a polybutadiene, 5 phr to 20 phr of a polyoctenamer, and 40 phr to 160 phr of a first filler. The second rubber component comprises 90 phr to 100 phr of a diene-based elastomer; and 20 phr to 160 phr of a second filler. Moreover, the present invention is directed to a rubber composition comprising a hydrogenated styrene butadiene rubber, 5 phr to 20 phr of a polyoctenamer, and 40 phr to 160 phr of a reinforcing filler.

Claims

1. A tire comprising a first rubber component and a second rubber component, wherein the first rubber component is cured to the second rubber component, and wherein the first rubber component comprises: 85 phr to 100 phr of a hydrogenated styrene butadiene rubber; 0 phr to 15 phr of a polybutadiene rubber; 5 phr to 20 phr of a polyoctenamer; 40 phr to 160 phr of a first filler; and wherein the second rubber component comprises: 90 phr to 100 phr of a diene-based elastomer; and 20 phr to 160 phr of a second filler.

2. The tire of claim 1, wherein the first rubber component comprises from 95 to 100 phr of the hydrogenated styrene-butadiene rubber and from 0 phr to 5 phr of the polybutadiene rubber.

3. The tire of claim 1, wherein the first rubber component comprises from 5 phr to 15 phr of the polyoctenamer.

4. The tire of claim 1, wherein the diene-based elastomer comprises polyisoprene rubber or polybutadiene rubber, or a combination thereof.

5. The tire of claim 1, wherein the tire has a tread and wherein the first component and the second component are components of the tread.

6. The tire of claim 5, wherein the first rubber component is a tread cap layer of the tread, and wherein the second rubber component is a second tread cap layer or a tread base layer of the tread.

7. The tire of claim 5, wherein the first rubber component is cured to the second rubber component essentially along a cylindrical plane extending along the circumferential direction of the tire.

8. The tire of claim 1, wherein the hydrogenated styrene-butadiene rubber has one or more of: i) less than 5% of nonhydrogenated vinyl groups, based on the total number of vinyl groups and ethyl groups of the hydrogenated styrene butadiene rubber; ii) less than 2% of double bonds along its main chain, based on the total number of bonds along the main chain, excluding number of bonds in styrene groups, vinyl groups, ethyl groups and other sidechain groups of the styrene butadiene rubber; and iii) from 90% to 99% hydrogenated double bonds.

9. The tire of claim 1, wherein the second rubber component comprises from 30 phr to 90 phr polyisoprene rubber; from 10 phr to 70 phr polybutadiene rubber; from 30 phr to 70 phr carbon black.

10. The tire of claim 1, wherein the first component comprises from 60 to 80 phr of the silica.

11. The tire of claim 1, wherein the styrene-butadiene rubber has a bound styrene content ranging from 20% to 35% and a butadiene content ranging from 50% to 80%, by weight.

12. The tire of claim 1, wherein the first rubber component comprises 15 phr to 30 phr of plasticizers including between 5 phr and 25 phr of an oil and 5 phr to 15 phr of a resin.

13. The tire of claim 12, wherein the resin is an alpha pinene based resin.

14. The tire of claim 12, wherein the ratio of resin to oil is within the range of 1:1 phr to 1:4 phr.

15. The tire of claim 1, wherein the polyoctenamer has one or more of: a glass transition temperature in a range from −50° C. to −80° C.; a weight average molecular weight which is within the range of 80,000 to 100,000 as determined by GPC; and a melting point which is within the range of 45° C. to 55° C. as measured by DSC in a second heating.

16. The tire of claim 1, wherein the polyoctenamer has a trans-microstructure contain which is within the range of 65% to 85%.

17. A rubber composition which is comprised of a hydrogenated styrene butadiene rubber, 5 phr to 20 phr of a polyoctenamer, and 40 phr to 160 phr of a reinforcing filler.

18. The rubber composition of claim 17 wherein the rubber composition is further comprised of 5 phr to 15 phr of high cis-polybutadiene rubber having a cis-microstructure content of at least 95%, 5 phr to 25 phr of an oil, and 5 phr to 15 phr of a resin.

19. The rubber composition of claim 18 wherein the resin is an alpha pinene based resin.

20. The rubber composition of claim 17, wherein the hydrogenated styrene butadiene rubber has one or more of: i) less than 5% of nonhydrogenated vinyl groups, based on the total number of vinyl groups and ethyl groups of the hydrogenated styrene butadiene rubber; ii) less than 2% of double bonds along its main chain, based on the total number of bonds along the main chain, excluding number of bonds in styrene groups, vinyl groups, ethyl groups and other sidechain groups of the styrene butadiene rubber; and iii) from 90% to 99% hydrogenated double bonds.

Description

DETAILED DESCRIPTION OF AN EMBODIMENT OF THE INVENTION

[0051] Below Table 1 shows rubber compositions for a first rubber compound. Control 1 and the Inventive Example 1 comprise a hydrogenated SSBR. However, only Inventive Example 1 comprises a polyoctenamer in accordance with a nonlimiting example of the present invention. The second control sample, Control 2, comprises a non-hydrogenated SSBR blended with a polybutadiene, in the absence of polyoctenamer.

TABLE-US-00001 TABLE 1 First Compound (phr) Inventive Material Control 1 Example 1 Control 2 Hydrogenated SSBR.sup.1 100 100 0 SSBR.sup.2 0 0 80 Polybutadiene.sup.3 0 0 20 Resin.sup.4 7 7 7 Waxes 1.5 1.5 1.5 Antioxidants 2.5 2.5 2.5 Oil.sup.5 14 14 14 Stearic Acid 3 3 3 Silica.sup.6 80 80 80 Polyoctenamer.sup.7 0 10 0 Silane.sup.8 8 8 8 Zinc oxide 2.5 2.5 2.5 Sulfur 1.5 1.5 1.5 Accelerator 2.5 2.5 2.5 DPG 3 3 3 Carbon black 2 2 2 .sup.1Hydrogenated solution polymerized styrene butadiene rubber having a glass transition temperature of about −30° C. .sup.2Solution polymerized styrene butadiene rubber having a glass transition temperature of −23° C. and a microstructure of 21% styrene, 63 BD % vinyl. as Sprintan ™ SLR-4602 of the company Trinseo .sup.3Polybutadiene having a glass transition temperature of −105° C. .sup.4Alpha-pinene based resin .sup.5TDAE oil .sup.6HDS Silica having a BET surface area of 200 .sup.7Vestenamer ™ 8012 of the company Evonik .sup.8SI266 ™ of the company Evonik
The compositions as given above in Table 1 were included in a tread cap layer and co-cured to a tread base layer having as a non-limiting example the composition given in Table 2 below.

TABLE-US-00002 TABLE 2 Material Second Compound (phr) Polybutadiene.sup.3 35 Natural Rubber 65 Carbon Black 45 Waxes 1.5 Antioxidants 2.5 Resin 2 Stearic acid 1.5 Accelerator 2.5 Zinc oxide 2.5 Sulfur 2

[0052] Properties of Control 1, Control 2 and Inventive Example 1 were determined as shown in Table 3. The tear strengths of the samples Control 1, Control 2 and the Inventive Example 1 to the Second Compound as given in Table 2 are shown in the first line of Table 3. The tear strength is relatively high for the compound Control 2 while Control 1 has a significantly lower tear strength to the base compound. In other words, it is easier to tear off or separate the Control 1 compound comprising the hydrogenated SSBR from the Second Compound as given in Table 2. Remarkably, the addition of the polyoctenamer as present in the Inventive Example 1 improves the tear strength behavior despite the use of the hydrogenated SSBR. The rebound values, which are indicators for the hysteresis behavior of the compounds and thus also for the expected rolling resistance, are also slightly but clearly improved for Inventive Example 1 compared to the control samples. Shore A hardness also remains at a comparable level to the control samples. Finally, and as mentioned before, the presence of the hydrogenated SSBR in Control 1 and Inventive Example 1 results in a remarkable increase in tensile strength compared to Control 2 which is larger than 50%. Inventive Example 1 can at least maintain the level of tear strength to the base or in other words allows still a good co-curability. Hysteresis behavior is also improved.

TABLE-US-00003 TABLE 3 First Compound Inventive Property Control 1 Example 1 Control 2 Tear strength to base [N/mm] .sup.a 5.4 8.4 8.7 Rebound 0° C. [%] .sup.b 10.5 13.2 10.6 Rebound 60° C. [%] .sup.b 58.1 61.1 58.4 Shore A hardness .sup.c 72.3 70.8 67.8 Tensile Strength [MPa] .sup.d 31.6 29.0 18.0 .sup.a Tear propagation test according to DIN 53539. .sup.b Rebound measured on a Zwick Roell ™ 5109 rebound resilience tester according to DIN 53512 at the given temperature. .sup.c Shore A hardness measured according to ASTM D2240. .sup.d Determined by a ring sample test based on ASTM D412; tensile strength is stress at break.

[0053] 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.