Tire composition and method for making thereof

Abstract

The disclosure relates to tire tread compositions and methods for making. The compositions include a rubber, a rosin ester resin and at least one filler. The rosin ester resin is characterized as having a PAN number of less than 25, an acid number less than 20, a hydroxyl number of less than 30, a combined acid number and hydroxyl value of less than 50. The tire tread composition has a wet grip resistance to rolling resistance indicator ratio ((tan δ at 0° C.)/tan δ at 60° C.) higher than a tire tread composition containing a comparable amount of a rosin ester having a combined acid number and hydroxyl value of more than 50.

Claims

1. A tire tread composition comprising a blend of: a rubber component, and based on 100 parts by weight (phr) of the rubber component; from 5 to 75 phr of a rosin ester resin having a PAN number of less than 25, an acid number of less than 20, a hydroxyl value of less than 30, a combined acid number and hydroxyl value of less than 50, a softening point (Tsp) of 60° C. to 170° C.; and a weight average molecular weight Mw of 700-1500 Da; from 30 to 200 phr of a filler; from 0 to 75 phr of a plasticizer; and wherein the tire tread composition has an increase in rolling resistance indicator (Tan δ at 60° C.) of less than 3%, and a decrease in wet grip indicator (Tan δ at 0° C.) of less than 1% after the resin is stored for 10-12 months at room temperature.

2. The tire tread composition of claim 1, wherein the combined acid number and hydroxyl value is less than 30.

3. The tire tread composition of claim 1, wherein the rosin ester resin has a PAN number of less than 10.

4. The tire tread composition of claim 1, wherein the rosin ester resin has a softening point (Tsp) of 75° C. to 160° C.

5. The tire tread composition of claim 1, wherein the rosin ester resin has a Tg of 0° C. to 115° C.

6. The tire tread composition of claim 1, wherein the rosin ester resin has a softening point (Tsp) of at least 60° C. and a PAN number of less than 10.

7. The tire tread composition of claim 1, wherein the rosin ester resin has an acid number of less than 20 and a PAN number of less than 10.

8. The tire tread composition of claim 1, wherein the rosin ester resin has a combined acid number and hydroxyl value of less than 30, and a PAN number of less than 10.

9. The tire tread composition of claim 1, wherein the tire tread composition has a wet grip resistance to rolling resistance indicator ratio ((tan δ at 0° C)/tan δ at 60° C.) higher than a tire tread composition containing a comparable amount of a rosin ester having a combined acid number and hydroxyl value of more than 50.

10. The tire tread composition of claim 1, further comprising a coupling agent selected from the group consisting of a sulfur-based coupling agent, an organic peroxide-based coupling agent, an inorganic coupling agent, a polyamine coupling agent, a resin coupling agent, a sulfur compound-based coupling agent, oxime-nitrosamine-based coupling agent, and sulfur.

11. The tire tread composition of claim 1, wherein the rubber component is selected from the group consisting of natural rubber (NR), styrene-butadiene rubber (SBR), butadiene rubber (BR), synthetic polyisoprene rubber, epoxylated natural rubber, polybutadiene rubber, nitrile- hydrogenated butadiene rubber NHBR, hydrogenated styrene-butadiene rubber HSBR, ethylene propylene diene monomer rubber, ethylene propylene rubber, maleic acid-modified ethylene propylene rubber, butyl rubber, isobutylene-aromatic vinyl or diene monomer copolymers, brominated-NR, chlorinated-NR, brominated isobutylene p-methylstyrene copolymer, chloroprene rubber, epichlorohydrin homopolymers rubber, epichlorohydrin-ethylene oxide or allyl glycidyl ether copolymer rubbers, epichlorohydrin-ethylene oxide-allyl glycidyl ether terpolymer rubbers, chlorosulfonated polyethylene, chlorinated polyethylene, maleic acid-modified chlorinated polyethylene, methylvinyl silicone rubber, dimethyl silicone rubber, methylphenylvinyl silicone rubber, polysulfide rubber, vinylidene fluoride rubbers, tetrafluoroethylene-propylene rubbers, fluorinated silicone rubbers, fluorinated phosphagen rubbers, styrene elastomers, thermoplastic olefin elastomers, polyester elastomers, urethane elastomers, polyamide elastomers, and combinations thereof.

12. The tire tread composition of claim 1, wherein the rubber component is styrene-butadiene rubber (SBR) or butadiene rubber (BR).

13. The tire tread composition of claim 1, wherein the rubber is coupled, star-branched, or functionalized with at least a sulfur compound, a silanol group, a silane group, or an epoxy group.

14. The tire tread composition of claim 1, wherein the plasticizer is selected from aliphatic acid esters, hydrocarbon processing oils, tall oil pitch and modified tall oil pitch, and combinations thereof.

15. The tire tread composition of claim 1, wherein the filler is selected from calcium carbonate, carbon nanotube, clay, mica, silica, silicates, talc, titanium dioxide, alumina, zinc oxide, starch, wood flour, carbon black, ultra-high molecular weight polyethylene (UHMWPE), particulate polymer gels, plasticized starch composites, and mixtures thereof.

16. The tire tread composition of claim 1, wherein the filler is surface treated prior to being added to the rubber composition.

17. A method for preparing a tire tread composition comprising: providing 0-100 parts by weight (phr) of a rubber component, providing from 5 to 75 phr of a rosin ester resin having a PAN number of less than 25, an acid number of less than 20, a hydroxyl value of less than 30, a combined acid number and hydroxyl value of less than 50, a softening point (Tsp) of 60° C. to 170° C.; and a weight average molecular weight Mw of 700-1500 Da; providing from 50 to 200 phr of a filler, and optionally up to 75 phr of a plasticizer; mixing the rubber component, the rosin ester resin, the filler, and the optional plasticizer to form a mixture; kneading the mixture; incorporating a cross-linking system into the kneaded mixture to form the tire tread composition; and wherein the tire tread composition has an increase in rolling resistance indicator (Tan δ at 60° C.) of less than 3%, and a decrease in wet grip indicator (Tan δ at 0° C.) of less than 1% after the resin is stored for 10-12 months at room temperature.

18. The method of claim 17, wherein the filler is selected from calcium carbonate, carbon nanotube, clay, mica, silica, silicates, talc, titanium dioxide, alumina, zinc oxide, starch, wood flour, carbon black, ultra-high molecular weight polyethylene (UHMWPE), particulate polymer gels, plasticized starch composites, and mixtures thereof.

19. The method of claim 17, wherein the cross-linking system comprises a coupling agent selected from the group of a sulfur-based coupling agent, an organic peroxide-based coupling agent, an inorganic coupling agent, a polyamine coupling agent, a resin coupling agent, a sulfur compound-based coupling agent, oxime-nitrosamine-based coupling agent, sulfur, and combinations thereof.

Description

EXAMPLES

(1) The following illustrative examples are intended to be non-limiting. In the examples, the following resins were incorporated into tire tread rubber compositions and tested for their performance. Table 1 shows the properties of the resins, where AN means acid number, and OH means hydroxyl value, both given in mg KOH/g.

(2) TABLE-US-00001 TABLE 1 Properties of Resins (AN + OH) Description AN OH mg KOH/g PAN Resin 1 alpha methyl styrene resin 0 0 0 0 having a Tsp of 85° C. Resin A a rosin ester having a Tsp 5 3 8 5 of 102.5° C. Resin B a rosin ester having a Tsp 5 6 11 21 of 90° C. Resin C a rosin ester having a Tsp 21 33 54 12 of 25° C. Resin D a rosin ester having a Tsp 11 15 26 7 of 100° C. Resin E a rosin ester having a Tsp 39 15 54 29 of 102° C. Resin F a rosin ester having a Tsp 7 10 17 4 of 97° C. Resin G a rosin ester having a Tsp 4 22 26 13 105° C.

(3) The resins were incorporated into rubber formulations as shown in Table 2. The formulations were mixed in a 379 ml Banbury type internal mixer using a 3-stage mixing protocol known in the art.

(4) In Examples 1, B, F, and G, both “fresh” and “aged” resins were used. “Fresh” refers to using resins within one (1) month of production in the sample. “Aged” refers to using resins that have been stored for 10-12 months at room temperature (˜23° C.). The performance properties, shown in Table 3, are labeled to reflect whether fresh or aged resins were used. The normalized Tan δ data in Table 3 is normalized against the fresh resin values of Example 1. The PAN is related to how the resins age, e.g., the low PAN helps to prevent the resins from aging/changing so that the aged resin provides similar results to that of the fresh resin.

(5) Determination of tan δ was carried out by DMA in temperature-sweep/mode in double shear mode from −60° C. to +100° C. with a heat rate of 1° C./min at 10 Hz, a dynamic strain of 0.1% (from −60° C. to −5° C.), and a dynamic strain of 3% (from −5° C. to 100° C.) using a Metravib+450N. Properties such as tensile strength, elongation, and modulus were measured following procedures described in ISO 37.

(6) TABLE-US-00002 TABLE 2 Tire Composition Formulations Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 9 Component (phr) Resin 1 Resin A Resin B Resin C Resin D Resin E Resin F Resin G SSBR (Buna ™ 48.12 48.12 48.12 48.12 48.12 48.12 48.12 48.12 4526-2) BR (Buna ™ CB24) 30 30 30 30 30 30 30 30 SSBR (Sprintan ™ 35 35 35 35 35 35 35 35 SLR 4602) Ultrasil ™ 7000 GR 80 80 80 80 80 80 80 80 (SA165) Carbon black - 5 5 5 5 5 5 5 5 N234 Silane Si-69 ™ 8 8 8 8 8 8 8 8 Zinc oxide RS ™ 3 3 3 3 3 3 3 3 Stearic acid 2 2 2 2 2 2 2 2 IPPD/antidegradant 1 1 1 1 1 1 1 1 6PPD/ 2 2 2 2 2 2 2 2 antidegradant TMQ/antioxidant 0.5 0.5 0.5 0.5 0.5 0.5 0.5 0.5 Antilux 654 (wax) 1 1 1 1 1 1 1 1 Resin 20 20 20 20 20 20 20 20 Rhenogran ™ CBS- 1.9 1.9 1.9 1.9 1.9 1.9 1.9 1.9 80 Rhenogran ™ DPG- 2.5 2.5 2.5 2.5 2.5 2.5 2.5 2.5 80 Rhenogran ™ IS 90- 2.3 2.3 2.3 2.3 2.3 2.3 2.3 2.3 65 Total: 242.3 242.3 242.3 242.3 242.3 242.3 242.3 242.3

(7) TABLE-US-00003 TABLE 3 Performance Properties Example 1 Example 2 Example 3 Example 4 Example 5 Example 6 Example 7 Example 9 Resin 1 Resin A Resin B Resin C Resin D Resin E Resin F Resin G Tan δ at 0° C. (−) 0.652 0.662 0.654 0.602 0.646 0.521 0.644 0.660 (fresh resin) Tan δ at 0° C. (−) 0.651 — 0.629 — — — 0.651 0.640 (aged resin) Normalized Tan δ 100 101 100 92 98 79 101 101 at 0° C. (−) (fresh resin) Normalized Tan δ 100 — 96 — — — 101 97 at 0° C. (−) (aged resin) Tan δ at 60° C. (−) 0.168 0.176 0.168 0.181 0.184 0.290 0.170 0.187 (fresh resin) Tan δ at 60° C. (−) 0.171 — 0.171 — — — 0.169 0.199 (aged resin) Normalized Tan δ 100 105 101 109 111 175 104 102 at 60° C. (−) (fresh resin) Normalized Tan δ 100 — 102 — — — 99 106 at 60° C. (−) (aged resin) Elongation at 472 501 478 491 474 524 480 542 break % Tensile MPa 21 21 19 19 19 19 21 21 strength Modulus MPa 1.4 1.4 1.1 1.1 1.1 1.3 1.3 1.3 50% Modulus MPa 2.4 2.2 1.9 2.0 1.9 2.0 2.2 2.1 100% Modulus MPa 10.7 10.0 9.4 9.6 9.8 8.8 10 9.2 300% Modulus MPa 4.6 4.5 5.0 4.8 5.1 4.3 4.5 4.4 300%/100%

(8) For the purposes of this specification and appended claims, unless otherwise indicated, all numbers expressing quantities, percentages or proportions, and other numerical values used in the specification and claims, are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained. It is noted that, as used in this specification and the appended claims, the singular forms “a,” “an,” and “the,” include plural references unless expressly and unequivocally limited to one referent. As used herein, the term “include” and its grammatical variants are intended to be non-limiting, such that recitation of items in a list is not to the exclusion of other like items that can be substituted or added to the listed items. As used herein, the term “comprising” means including elements or steps that are identified following that term, but any such elements or steps are not exhaustive, and an embodiment can include other elements or steps. Although the terms “comprising” and “including” have been used herein to describe various aspects, the terms “consisting essentially of” and “consisting of” can be used in place of “comprising” and “including” to provide for more specific aspects of the disclosure and are also disclosed.

(9) Unless otherwise specified, the recitation of a genus of elements, materials or other components, from which an individual component or mixture of components can be selected, is intended to include all possible sub-generic combinations of the listed components and mixtures thereof.

(10) The patentable scope is defined by the claims, and can include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims. To an extent not inconsistent herewith, all citations referred to herein are hereby incorporated by reference.