RUBBER COMPOSITION AND TIRE

Abstract

The present invention is directed to a rubber composition comprising 70 phr to 100 phr of at least one styrene butadiene rubber, 0 phr to 30 phr of at least one further diene-based rubber, from 40 phr to 200 phr of at least one filler, at least 5 phr of aluminum hydroxide, and at least 0.5 phr of a rosin based resin. Moreover, the present invention is directed to a tire comprising such a rubber composition.

Claims

1. A rubber composition comprising: 70 phr to 100 phr of at least one styrene butadiene rubber, 0 phr to 30 phr of at least one further diene-based rubber, from 40 phr to 200 phr of at least one filler, at least 5 phr of aluminum hydroxide, and at least 0.5 phr of a rosin based resin.

2. The rubber composition according to claim 1 wherein the rubber composition comprises from 5 phr to 80 phr of the aluminum hydroxide.

3. The rubber composition according to claim 1 wherein the rubber composition comprises from 0.5 phr to 15 phr of the rosin based resin.

4. The rubber composition according to claim 1 wherein the rosin based resin is based on one or more of gum rosin and dimerized gum rosin.

5. The rubber composition according to claim 1 wherein the rubber composition comprises from 20 phr to 80 phr of a traction resin.

6. The rubber composition according to claim 5 wherein the traction resin is selected from at least one member of the group consisting of DCPD resins, CPD resins, terpene resins, C5 resins, C9 resins, coumarone indene resins, styrene-alphamethylstyrene resins or combinations of those.

7. The rubber composition according to claim 6 wherein the traction resin is selected from at least one member selected from the group consisting of DCPD resins, CPD resins, and C5 resins.

8. The rubber composition according to claim 1 wherein the styrene butadiene rubber is a solution polymerized styrene butadiene rubber and wherein the diene-based rubber is one or more of synthetic polyisoprene and natural rubber.

9. The rubber composition according to claim 8 wherein the rubber composition comprises from 70 phr to 90 phr of the solution polymerized styrene butadiene rubber and from 10 phr to 30 phr of the natural rubber or the synthetic polyisoprene.

10. The rubber composition according to claim 1 wherein the styrene butadiene rubber is functionalized for the coupling to silica.

11. The rubber composition according to claim 1 wherein the filler is comprised predominantly of silica.

12. The rubber composition according to claim 1 wherein the filler comprises less than 10 phr of carbon black and at least 40 phr of silica.

13. The rubber composition according to claim 1, wherein the rubber composition comprises at least 105 phr of silica and less than 10 phr of carbon black.

14. The rubber composition according to claim 1 wherein the styrene butadiene rubber has a glass transition temperature which is within the range of −51° C. to −86° C.

15. The rubber composition according to claim 14 wherein the rubber composition comprises from 20 phr to 80 phr of a traction resin having a glass transition temperature which is within the range of 35° C. to 60° C.

16. The rubber composition according to claim 14 wherein the rubber composition comprises from 1 phr to 9 phr of a vegetable oil having a glass transition temperature which is within the range of −75° C. to −100° C.

17. The rubber composition according to claim 1 wherein the rubber composition comprises predominantly silica as a filler and wherein the composition further comprises a mercapto silane within a range of 10 phr to 20 phr.

18. The rubber composition according to claim 1 wherein the aluminum hydroxide has one or more of (i) a D50 particle diameter within a range of 0.2 μ.m and 5 μm, or (ii) a BET surface area within a range of 1 m.sup.2/g to 20 m.sup.2/g.

19. The rubber composition according to claim 1 wherein the silica has a BET surface area within a range of 150 m.sup.2/g to 220 m.sup.2/g.

20. A tire comprising the rubber composition according to claim 1.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0070] The structure, operation, and advantages of the invention will become more apparent upon contemplation of the following description taken in conjunction with the accompanying drawings, wherein

[0071] FIG. 1 is a schematic cross section of a tire comprising a rubber component with the rubber composition in accordance with an embodiment of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

[0072] FIG. 1 is a schematic cross-section of a tire 1 according to an embodiment of the invention. The tire 1 has a plurality of tire components such as a tread 10, an innerliner 13, a belt comprising four belt plies 11, a carcass ply 9, two sidewalls 2, and two bead regions 3, bead filler apexes 5 and beads 4. The example tire 1 is suitable, for example, for mounting on a rim of a vehicle, e.g. a truck or a passenger car. As shown in FIG. 1, the belt plies 11 may be covered by an overlay ply 12 and/or may include one or more breaker plies. The carcass ply 9 includes a pair of axially opposite end portions 6, each of which is associated with a respective one of the beads 4. Each axial end portion 6 of the carcass ply 9 may be turned up and around the respective bead 4 to a position to anchor each axial end portion 6. The turned-up portions 6 of the carcass ply 9 may engage the axial outer surfaces of two flippers 8 and axial inner surfaces of two chippers 7 which are also considered as tire components. As shown in FIG. 1, the example tread 10 may have circumferential grooves 20, each groove 20 essentially defining a U-shaped opening in the tread 10. The main portion of the tread 10 may be formed of one or more tread compounds. Moreover, the grooves 20, in particular the bottoms and/or sidewalls of the grooves 20 could be reinforced by a rubber compound having a higher hardness and/or stiffness than the remaining tread compound. Such a reinforcement may be referred to herein as a groove reinforcement.

[0073] While the embodiment of FIG. 1 suggests a plurality of tire components including for instance apexes 5, chippers 7, flippers 8 and overlay 12, such and further components are not mandatory for the invention. Also, the turned-up end of the carcass ply 9 is not necessary for the invention or may pass on the opposite side of the bead area 3 and end on the axially inner side of the bead 4 instead of the axially outer side of the bead 4. The tire could also have for instance a different number of grooves 20, e.g. less than four grooves.

[0074] The rubber composition in accordance with a preferred embodiment of the invention is used in a tread or tread layer contacting the ground or road. In an embodiment, the tread 10 of the tire 1 or of another tire comprises a rubber composition according to the Inventive Example as identified in Table 1 below. The Comparative Examples 1 to 4 of Table 1 comprise different amounts of aluminum hydroxide but have all the same rubber matrix The Inventive Example has a moderate amount of aluminum hydroxide and in addition a rosin based resin.

TABLE-US-00001 TABLE 1 phr Comparative Comparative Comparative Comparative Inventive Materials Example 1 Example 2 Example 3 Example 4 Example SBR.sup.1 80 80 80 80 80 NR.sup.2 20 20 20 20 20 Silica.sup.3 135 135 135 135 135 Resin.sup.4 57 57 57 57 57 Rosin based resin.sup.5 0 0 0 0 2 Aluminum hydroxide.sup.6 0 15 20 25 20 Vegetable Oil.sup.7 4 4 4 4 4 Silane 1.sup.8 13.5 13.5 13.5 13.5 13.5 Fatty Acid Ester 2 2 2 2 2 BDBzTH.sup.9 2.2 2.2 2.2 2.2 2.2 Antidegradants.sup.10 4.1 4.1 4.1 4.1 4.1 Sulfur 1 1 1 1 1 Waxes 2.3 2.3 2.3 2.3 2.3 Zinc Oxide 1.1 1.1 1.1 1.1 1.1 Silane 2.sup.11 1 1 1 1 1 Accelerator 1.sup.12 3 3 3 3 3 Accelerator 2.sup.13 1.3 1.3 1.3 1.3 1.3 .sup.1as Sprintan ™ SLR 3402 from the company Trinseo, having a Tg of −62° C. and a thiol-alkoxysilane functionalization .sup.2natural rubber .sup.3as Zeosil ™ 1165 MP having a BET surface area of 160 g/m.sup.2 .sup.4as Oppera ™ 383 from Exxon Mobil .sup.5gum rosin .sup.6Al(OH).sub.3 having a BET surface area of 6 m.sup.2/g, d50 of 1.0 μm, d90 of 2.4 μm, and d10 of 0.5 μm, and a density of 2.4 g/cm.sup.3 .sup.7sunflower oil having a Tg of about −80° C. .sup.8as NXT ™ from Momentive .sup.91,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane with 10% oil and carbon black by weight .sup.10including dihydroquinolines and phenylenediamines .sup.1150% bis-triethoxysilylpropyl tetrasulfide and 50% carbon black as X50S from Evonik .sup.12diphenylguanidine .sup.13N-Tert-Butyl-2-benzothiazolesulfenamide

[0075] Table 2 shows test data obtained with the Comparative Examples and the Inventive Example listed above in Table 1. As apparent from the below results, wet grip is significantly improved for the Inventive Example by a relatively small quantity of added rosin resin. Wet handling is also significantly improved compared to Comparative Example 1 (without aluminum hydroxide) but also compared to Comparative Example 2 comprising the same amount of aluminum hydroxide as the Inventive Example. Dry handling is surprisingly also significantly improved over Comparative Examples 1 and 3. Dry breaking remains essentially flat. The tensile strength is kept on a good level, despite the addition of aluminum hydroxide. Overall, the non-limiting Inventive Example provides an advanced balance of properties.

TABLE-US-00002 TABLE 2 Comparative Comparative Comparative Comparative Inventive Property Example 1 Example 2 Example 3 Example 4 Example Wet grip .sup.a 100 104 105 107 115 Wet handling .sup.b 100 — 102 — 105 Dry handling .sup.c 100 — 96 — 103 Dry braking .sup.d 100 — 100 — 100 Tensile strength .sup.e 19 18 18 17 18 .sup.a Laboratory tests, results normalized to Comparative Example 1, based on determination of a transmittable friction force on a linear friction tester .sup.b Tire tests, results normalized to Comparative Example 1 .sup.c Tire tests, results normalized to Comparative Example 1 .sup.d Tire tests, results normalized to Comparative Example 1 .sup.e Laboratory test, wherein tensile strength is stress at break, using a ring sample according to ASTM D412

[0076] 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.