Tire sidewall composition

Abstract

A sidewall composition for forming tire sidewalls is provided. The sidewall composition includes a rubber composition, a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition, and an additive composition for curing and / or stabilization. Advantageously, sidewalls can be formed from the sidewall composition with improved rolling resistance while reducing or eliminating the use of 6PPD with equal or better ozone resistance.

Description

TIRE SIDEWALL COMPOSITIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of U.S. provisional application Serial No. 63 / 536,581 filed September 5, 2023, the disclosure of which is hereby incorporated in its entirety by reference herein.TECHNICAL FIELD

[0002] In at least one aspect, the present invention is related to compositions for forming tire sidewalls.BACKGROUND

[0003] Tires include several components, such as the tire sidewalls and tread blocks are formed from rubber compositions. Such rubber compositions include natural rubber, synthetic rubbers, and various additives for curing and stabilization. A particularly useful additive is the antiozonant 6PPD. Although 6PPD works well in mitigating the deleterious effects of ozone on tire rubber, it has been found to raise some environmental concerns. It has recently been found that 6PPD is oxidized to certain quinones that present a health risk to aquatic organisms.

[0004] Accordingly, there is a need for improved tire component compositions that avoid or reduce the amounts of 6PPD used in tire components.SUMMARY

[0005] In at least one aspect, a sidewall composition for forming tire sidewalls is provided. The sidewall composition includes a rubber composition, a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition, and an additive composition for curing and / or stabilization. Advantageously, sidewalls can be formed from the sidewall composition with improved rolling resistance while reducing or eliminating the use of 6PPD with equal or better ozone resistance.

[0006] In another aspect, a method for forming a sidewall is provided. The method includes a step of providing a sidewall composition as set forth above for forming tire sidewalls. The sidewall composition includes a rubber composition, a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition, and an additive composition for curing and / or stabilization. The sidewall composition is formed by compounding its components. The sidewall composition is extruded after mixing into sidewall sheets. A pre-molded tire is constructed from tire components including the sidewall sheets. The pre-molded tire is molded and cured to form the tire.

[0007] The foregoing summary is illustrative only and is not intended to be in any way limiting. In addition to the illustrative aspects, embodiments, and features described above, further aspects, embodiments, and features will become apparent by reference to the drawings and the following detailed description.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] For a further understanding of the nature, objects, and advantages of the present disclosure, reference should be had to the following detailed description, read in conjunction with the following drawings, wherein like reference numerals denote like elements and wherein:

[0009] FIGURE 1. Schematic illustration of a pneumatic tire having a sidewall made with a sidewall composition that resists ozone degradation while improving rolling resistance.DETAILED DESCRIPTION

[0010] Reference will now be made in detail to presently preferred compositions, embodiments, and methods of the present invention, which constitute the best modes of practicing the invention presently known to the inventors. The Figures are not necessarily to scale. However, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. Therefore, specific details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for any aspect of the invention and / or as a representative basis for teaching one skilled in the art to variously employ the present invention.

[0011] Except in the examples, or where otherwise expressly indicated, all numerical quantities in this description indicating amounts of material or conditions of reaction and / or use are to be understood as modified by the word "about" in describing the broadest scope of the invention. Practice within the numerical limits stated is generally preferred. Also, rmless expressly stated to the contrary: all R groups (e.g. Ri where i is an integer) include hydrogen, alkyl, lower alkyl, Ci-6 alkyl, C6-io aryl, C6-io heteroaryl, -NO2, -NH2, -N(R’R”), -N(R’R”R’”)+L-, Cl, F, Br, -CF3, -CCl3, -CN, - SO3H, -PO3H2, -COOH, -CO2R’, -COR’, -CHO, -OH, -OR’, -O M+, -SO3M+, -PO3’M+, -COO M+, - CF2H, -CF2R’, -CFH2, and -CFR’R” where R’, R” and R’” are C1-10alkyl or C6-18aryl groups M is a metal atom (e.g., Na, K, Li, etc.) and L" is a negative counter ion (e.g., C1-, Br-, etc.); single letters (e.g., "n" or "0") are 1, 2, 3, 4, or 5; in the compounds disclosed herein including compounds described by formula or by name, a CH bond can be substituted with alkyl, lower alkyl, C1-6alkyl, C6-10aryl, C6-10heteroaryl, -NO2, -NH2, -N(R’R”), -N(R’R”R’”)+L-, Cl, F, Br, -CF3, -CCI3, -CN, -SO3H, -PO3H2, - COOH, -CO2R’, -COR’, -CHO, -OH, -OR’, -O'M+, -SO3M+, -PO3'M+, -COO M+, -CF2H, -CF2R’, - CFH2, and -CFR’R” where R’, R” and R’” are CMO alkyl or C6-18aryl groups M is a metal atom (e.g., Na, K, Li, etc.); percent, "parts of," and ratio values are by weight; the term "polymer" includes "oligomer," "copolymer," "terpolymer," and the like; molecular weights provided for any polymers refers to weight average molecular weight unless otherwise indicated; the description of a group or class of materials as suitable or preferred for a given purpose in connection with the invention implies that mixtures of any two or more of the members of the group or class are equally suitable or preferred; description of constituents in chemical terms refers to the constituents at the time of addition to any combination specified in the description, and does not necessarily preclude chemical interactions among the constituents of a mixture once mixed; the first definition of an acronym or other abbreviation applies to all subsequent uses herein of the same abbreviation and applies mutatis mutandis to normal grammatical variations of the initially defined abbreviation; and, unless expressly stated to the contrary, measurement of a property is determined by the same technique as previously or later referenced for the same property.

[0012] The term “alkyl” refers to C1-20inclusive, linear (i.e., “straight-chain”), branched, saturated or at least partially and in some cases fully unsaturated (i.e., alkenyl and alkynyl) hydrocarbon chains, including for example, methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl,pentyl, hexyl, octyl, ethenyl, propenyl, butenyl, pentenyl, hexenyl, octenyl, butadienyl, propynyl, butynyl, pentynyl, hexynyl, heptynyl, and allenyl groups. “Branched” refers to an alkyl group in which a lower alkyl group, such as methyl, ethyl or propyl, is attached to a linear alkyl chain. “Lower alkyl” refers to an alkyl group having 1 to about 8 carbon atoms (i.e., a C1-8alkyl), e.g., 1, 2, 3, 4, 5, 6, 7, or 8 carbon atoms. “Higher alkyl” refers to an alkyl group having about 10 to about 20 carbon atoms, e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, or 20 carbon atoms.

[0013] It is also to be understood that this invention is not limited to the specific embodiments and methods described below, as specific components and / or conditions may, of course, vary. Furthermore, the terminology used herein is used only for the purpose of describing particular embodiments of the present invention and is not intended to be limiting in any way.

[0014] It must also be noted that, as used in the specification and the appended claims, the singular form "a," "an," and "the" comprise plural referents unless the context clearly indicates otherwise. For example, reference to a component in the singular is intended to comprise a plurality of components.

[0015] The term “comprising” is synonymous with “including,” “having,” “containing,” or “characterized by.” These terms are inclusive and open-ended and do not exclude additional, unrecited elements or method steps.

[0016] The phrase “consisting of’ excludes any element, step, or ingredient not specified in the claim. When this phrase appears in a clause of the body of a claim, rather than immediately following the preamble, it limits only the element set forth in that clause; other elements are not excluded from the claim as a whole.

[0017] The phrase “consisting essentially of’ limits the scope of a claim to the specified materials or steps, plus those that do not materially affect the basic and novel characteristic(s) of the claimed subject matter.

[0018] With respect to the terms “comprising,” “consisting of,” and “consisting essentially of,” where one of these three terms is used herein, the presently disclosed and claimed subject matter can include the use of either of the other two terms.

[0019] The phrase “composed of" means “including” or “comprising.” Typically, this phrase is used to denote that an object is formed from a material.

[0020] The term “residue” means a portion, and typically a major portion, of a molecular entity, such as a molecule or a part of a molecule such as a group, which has underwent a chemical reaction and is now covalently linked to another molecular entity. In a refinement, the term "residue," when used in reference to a monomer or monomer unit means the remainder of the monomer unit after the monomer unit has been incorporated into a polymer structure, such as a binder.

[0021] It should also be appreciated that integer ranges explicitly include all intervening integers. For example, the integer range 1-10 explicitly includes 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Similarly, the range 1 to 100 includes 1, 2, 3, 4. . . . 97, 98, 99, 100. Similarly, when any range is called for, intervening numbers that are increments of the difference between the upper limit and the lower limit divided by 10 can be taken as alternative upper or lower limits. For example, if the range is 1.1. to 2.1 the following numbers 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0 can be selected as lower or upper limits.

[0022] In the examples set forth herein, concentrations, temperature, and reaction conditions (e.g., pressure, pH, flow rates, etc.) can be practiced with plus or minus 50 percent of the values indicated rounded to or truncated to two significant figures of the value provided in the examples. In a refinement, concentrations, temperature, and reaction conditions (e.g., pressure, pH, flow rates, etc.) can be practiced with plus or minus 30 percent of the values indicated rounded to or truncated to two significant figures of the value provided in the examples. In another refinement, concentrations, temperature, and reaction conditions (e.g., pressure, pH, flow rates, etc.) can be practiced with plus or minus 10 percent of the values indicated rounded to or truncated to two significant figures of the value provided in the examples.

[0023] Throughout this application, where publications are referenced, the disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains.

[0024] Abbreviations:

[0025] “6PPD” means A-(l ,3-Dimethylbutyl)-A'-phenyl-p-phenylenediamine.

[0026] “EPDM” means ethylene propylene diene monomer rubber.

[0027] "EPM" means “ethylene-propylene copolymer” or “ethylene-propylene rubber."

[0028] “POES” means polyolefin elastomers.

[0029] “phr” means parts per 100 parts by weight of rubber.

[0030] “TBBS” means N-tert-butyl-benzothiazole-2-sulfenamide.

[0031] Figure 1 provides a schematic illustration of a pneumatic tire having a tire sidewall that is formed from a sidewall composition with improved rolling resistance. Advantageously, the Pneumatic tire 10 includes tread block 12 disposed over undertread 14, which is disposed over carcass 16. Cap piles 20 and belts 22 are interposed between the undertread 14 and carcass 16. Sidewall 23, which abuts thread block 12, is also depicted. The additives and compositions set forth herein are used for forming sidewall 23. Tread block 12 includes treads 24 defined by the tread rubber and interposed between blocks 26. Tread block 12 can also include ribs 28, which is a pattern of tread features aligned around the circumference of the tire. Tread block 12 also includes shoulder sections 30 and 32, which have dimples 34 and sipes 36 defined by the tread rubber therein.

[0032] In at least one aspect, a sidewall composition for forming tire sidewalls is provided. The sidewall composition includes a rubber composition, a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition, and an additive composition for curing and / or stabilization. In a refinement, the additive composition includes a component selected from thegroup consisting of activators, antiozonants, antioxidant curatives, accelerators, and combinations thereof.

[0033] In another aspect, the sidewall composition is provided as a first pass sub-composition and a second pass sub-composition. The first pass sub-composition includes the rubber composition and the silane-grafted polyolefin composition while the second pass sub-composition includes a portion of the additive composition. In a refinement, the first pass sub-composition further includes at least one filler and at least one activator. The at least one filler can be selected from the group consisting of carbon black, silica, clay, calcium carbonate, and combinations thereof. In a refinement, the second pass sub-composition includes at least one curative and at least one accelerator.

[0034] In another aspect, the rubber composition includes a component selected from the group consisting of natural rubber, butadiene rubber, ethylene propylene diene monomer rubber, and combinations thereof.

[0035] In another aspect, the silane-grafted polyolefin composition and / or residues thereof is present in an amount from about 5 to 20 phr.

[0036] In another aspect, a method for forming a sidewall is provided. The method includes a step of providing a sidewall composition as set forth above for forming tire sidewalls. The sidewall composition includes a rubber composition, a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition, and an additive composition for curing and / or stabilization. The sidewall composition is formed by compound mixing its components (e.g., at temperatures from 100 to 160 °C). The sidewall composition is extruded after mixing into sidewall sheets. A pre-molded tire is constructed from the tire components of Figure 1 which include the sidewall sheets. The pre-molded tire is molded and cured to form the tire. Typically molding temperatures of 130 °C to 220 °C can be used.

[0037] In another aspect, the sidewall composition is prepared by mixing its components in a plurality of mixing stages. In a refinement, the sidewall composition is prepared by a first mixing stage in which a first pass sub-composition is compounded and a second mixing stage in which a second pass sub-composition is compounded.

[0038] In another aspect, the silane-grafted polyolefin composition and / or residues thereof includes a silane-grafted styrene-ethylene-butylene-styrene polymer or elastomer and / or residues thereof. In a refinement, the silane-grafted polyolefin composition and / or residues thereof includes a silane-grafted polyethylene, a silane-grafted butylene, a silane-grafted styrene, or combinations thereof and / or residues thereof. In another refinement, the silane-grafted polyolefin composition and / or residues thereof include a silane-grafted low-density polyethylene, a silane-grafted high-density polyethylene, a silane-grafted ultrahigh molecular polyolefin, or combinations thereof and / or residues thereof. Advantageously, the silane-grafted polyolefin composition can include a first silane-grafted polyolefin that can be silane-grafted olefin block copolymer.

[0039] In another aspect, the silane-grafted polyolefin composition and / or residues thereof further includes at least one additional silane-grafted polyolefin and / or residues thereof. In a refinement, the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin is selected from the group consisting of silane-grafted ethylene / a-olefin copolymers, silane- grafted olefin block copolymers, and combinations thereof. In another refinement, the first silane- grafted polyolefin and / or the at least one additional silane-grafted polyolefin is selected from the group consisting of silane-grafted olefin homopolymers, silane-grafted blends of homopolymers, copolymers of two or more olefins, silane-grafted blends of copolymers of two or more olefins, and a combination of silane-grafted olefin homopolymers blended with copolymers of two or more olefins. In a further refinement, the first silane-grafted polyolefin and / or the at least one additional silane- grafted polyolefin includes a silane-grafted copolymer of an olefin selected from the group consisting of ethylene, propylene, 1 -butene, 1 -propene, 1 -hexene, 1 -octene, C9-16 olefins, and combinations thereof.

[0040] In another aspect, the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin includes a silane-grafted polyolefin selected from the group consisting of silane-grafted block copolymers, silane-grafted ethylene propylene diene monomer polymers, silane- grafted ethylene octene copolymers, silane-grafted ethylene butene copolymers, silane-grafted ethylene a-olefm copolymers, silane-grafted 1 -butene polymer with ethene, polypropylene homopolymers, silane-grafted methacrylate-butadiene-styrene polymers, silane-grafted polyolefin swith isotactic propylene units with random ethylene distribution, styrenic block copolymers, silane- grafted styrene ethylene butylene styrene copolymer, and combinations thereof.

[0041] In another aspect, silane-grafted polyolefin component is formed by silane grafting at least one base polyolefin. Silane grafting is achieved by combining a silane mixture combined with one or more polyolefins. The silane mixture may include one or more silanes, oils, peroxides, antioxidants, and / or other components such as a grafting initiator. The synthesis of the silane-grafted polyolefins may be performed as described in the grafting steps outlined using the single-step Monosil process or the two-step Sioplas process as disclosed in U.S. patent application Ser. No. 15 / 836,436, filed Dec. 8, 2017, entitled “Shoe Soles, Compositions, And Methods Of Making The Same” which is herein incorporated by reference in its entirety. In a refinement, the first silane-grafted polyolefin is formed from a blend that includes a polyolefin and a silane crosslinker has the following formula:wherein R1, R2, and R3are each independently H or C1-8alkyl. In a refinement, R1, R2, and R3are each independently methyl, ethyl, propyl, or butyl. Additional details of silane-grafted polyolefins and silane grafting are found in US Pat. Nos 10774168 and 10779608, the entire disclosures of which are hereby incorporated by reference in its entirety. In a refinement, the silane grafted silane-grafted polyolefin can be described by the following formula:where the polymer backbone can be a polymer or copolymer backbone. In a further refinement, the silane-grafted polymer is mixed with a silanol-forming condensation catalyst and then exposed tohumidity and / or heat to effect crosslinking of the copolymer in a two-step reaction. Alternatively, the composition can be cross-linked via ‘Ambicat’ where the ambient moisture is sufficient to crosslink over a longer time period (e.g., about 48 hours). First, the water hydrolyzes the silane to produce a silanol. The silanol then condenses to form intermolecular, irreversible Si — 0 — Si crosslink sites. Additional details of silane-grafted polyolefins and silane grafting are found in US Pat. Nos 10774168 and 10779608, the entire disclosures of which are hereby incorporated by reference in its entirety.

[0042] In another aspect, the density of the base polyolefin is less than 1.0 g / cm3, including less than about 0.92 g / cm3. The density may be from about 0.85 g / cm3to about 0.96 g / cm3. In some refinements, the density is at least 0.84 g / cm3, including at least about 0.862 g / cm3.

[0043] In another aspect, the number average molecular weight of the silane-grafted polyolefins may be in the range of from about 4,000 g / mol to about 30,000 g / mol, including from about 5,000 g / mol to about 25,000 g / mol and from about 6,000 g / mol to about 14,000 g / mol. The weight average molecular weight of the grafted polymers may be from about 8,000 g / mol to about 60,000 g / mol, including from about 10,000 g / mol to about 30,000 g / mol.

[0044] In another aspect, the polymer composition further comprises additives or residues thereof selected from the group consisting of antioxidants, process aids, fillers, blowing agents, activators, coagents, curatives (e.g., peroxide, sulfur), rubbers (e.g., SSBR), colorants, UV stabilizers, and combinations thereof. Process aids are agents that improve flow and processability. Examples of process aids include but are not limited to, stearic acid, octadecanoic acid, and polyethylene glycol. Accelerators are compounds that increase the reaction rate.

[0045] The following examples illustrate the various embodiments of the present invention. Those skilled in the art will recognize many variations that are within the spirit of the present invention and scope of the claims.

[0046] Table 1 provides comparative composition examples and inventive example 1. It should be appreciated that practice within (i.e., + / -), in increasing order of preference, 30%, 20%, 10%, 5%, or 2% of the amounts indicated are also contemplated. Comparative Example 1 includes 6PPDwhile Comparative Example 2 and Example 1 do not include 6PPD. Example 1 includes FORTREX™, which is a silane-grafted polyolefin.

[0047] Table 1. Compositions for preparing tire sidewalls.

[0048] Table 2 provide physical properties of sidewalls prepared from the compositions of Table 1 . The dynamic ozone test indicates the resistance of a rubber composition to resist ozone induced cracking. The results show that Comparative Example 1 and Example 1 both pass at 24 hours). However, Comparative Example 2 which does not include 6PPD or FORTREX™ fails the test at 24 hours. It is noted that Comparative Example 1 and Example 1 have a lower tan delta than Comparative Example 2. This difference can provide better rolling resistance for Comparative Example 1 and Example 2.

[0049] Table 2. Properties of sidewalls formed from the compositions of Table 2.

[0050] While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.

Claims

WHAT IS CLAIMED IS:

1. A sidewall composition for forming tire sidewalls comprising: a rubber composition; a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition; and an additive composition for curing and / or stabilization.

2. The sidewall composition of claim 1, wherein the additive composition includes a component selected from the group consisting of activators, antiozonants, antioxidant curatives, accelerators, and combinations thereof.

3. The sidewall composition of claim 1, wherein the sidewall composition is provided as a first pass sub-composition and a second pass sub-composition, wherein the first pass subcomposition includes the rubber composition and the silane-grafted polyolefin composition while the second pass sub-composition includes a portion of the additive composition.

4. The sidewall composition of claim 3, wherein the first pass sub-composition further includes at least one filler and at least one activator.

5. The sidewall composition of claim 4, wherein the at least one filler is selected from the group consisting of carbon black, silica, clay, calcium carbonate, and combinations thereof.

6. The sidewall composition of claim 4, wherein the second pass sub-composition includes at least one curative and at least one accelerator.

7. The sidewall composition of claim 4, wherein the rubber composition includes a component selected from the group consisting of natural rubber, butadiene rubber, ethylene propylene diene monomer rubber, and combinations thereof.

8. The sidewall composition of claim 4, wherein the silane-grafted polyolefin composition and / or residues thereof is present in an amount from about 5 to 20 phr.

9. The sidewall composition of claim 1, wherein the silane-grafted polyolefin composition and / or residues thereof includes a first silane-grafted styrene-ethylene-butylene-styrene polymer or elastomer and / or residues thereof.

10. The sidewall composition of claim 1, wherein the silane-grafted polyolefin composition and / or residues thereof includes a silane-grafted polyethylene, a silane-grafted butylene, a silane-grafted styrene, or combinations thereof and / or residues thereof.

11. The sidewall composition of claim 1, wherein the silane-grafted polyolefin composition and / or residues thereof include a silane-grafted low-density polyethylene, a silane-grafted high-density polyethylene, a silane-grafted ultrahigh molecular polyolefin, or combinations thereof and / or residues thereof.

12. The sidewall composition of claim 1, wherein the silane-grafted polyolefin composition includes a first silane-grafted olefin polyolefin and / or residues thereof.

13. The sidewall composition of claim 12, wherein the silane-grafted polyolefin composition further includes at least one additional silane-grafted polyolefin and / or residues thereof.

14. The sidewall composition of claim 13, wherein and / or the at least one additional silane- grafted polyolefin is selected from the group consisting of silane-grafted ethylene / a-olefin copolymers, silane-grafted olefin block copolymers, and combinations thereof.

15. The sidewall composition of claim 13 , wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin is selected from the group consisting of silane- grafted olefin homopolymers, silane-grafted blends of homopolymers, copolymers of two or more olefins, silane-grafted blends of copolymers of two or more olefins, and a combination of silane- grafted olefin homopolymers blended with copolymers of two or more olefins.

16. The sidewall composition of claim 13, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin includes a silane-grafted copolymer of an olefin selected from the group consisting of ethylene, propylene, 1 -butene, 1 -propene, 1 -hexene, 1- octene, C9-16olefins, and combinations thereof.

17. The sidewall composition of claim 13, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin includes a silane-grafted polyolefin selected from the group consisting of silane-grafted block copolymers, silane-grafted ethylene propylene diene monomer polymers, silane-grafted ethylene octene copolymers, silane-grafted ethylene butene copolymers, silane-grafted ethylene a-olefm copolymers, silane-grafted 1 -butene polymer with ethene, polypropylene homopolymers, silane-grafted methacrylate-butadiene-styrene polymers, silane-grafted polyolefin s with isotactic propylene units with random ethylene distribution, styrenic block copolymers, silane-grafted styrene ethylene butylene styrene copolymer, and combinations thereof.

18. The sidewall composition of claim 1, wherein the silane-grafted polyolefin composition includes a silane-grafted polyolefin that is formed from a blend that includes a polyolefin and a silane crosslinker has the following formulaRI, R2, and R3are each independently H or C1-8alkyl.

19. The sidewall composition of claim 13, wherein R1, R2, and R3are each methyl, ethyl, propyl, or butyl.

20. A method for forming a sidewall comprising: a) providing a sidewall composition for forming tire sidewalls comprising: a rubber composition; a silane-grafted polyolefin composition and / or residues thereof dispersed in the rubber composition; and an additive composition for curing and / or stabilization, wherein the sidewall composition is formed by compound mixing its components; b) extruding the sidewall composition after mixing into sidewall sheets; c) constructing a pre-molded tire from tire components that include the sidewall sheets; and d) molding and curing the pre-molded tire to form a tire.

21. The method of claim 20, wherein the additive composition includes a component selected from the group consisting of activators, antiozonants, antioxidant curatives, accelerators, and combinations thereof.

22. The method of claim 20 wherein the sidewall composition is prepared by mixing its components in a plurality of mixing stages.

23. The method of claim 22, wherein the sidewall composition is prepared by a first mixing stage in which a first pass sub-composition is compounded and a second mixing stage in which a second pass sub-composition is compounded.

24. The method of claim 23, wherein the first pass sub-composition includes the rubber composition and the silane-grafted polyolefin composition while the second pass sub-composition includes a portion of the additive composition.

25. The method of claim 24, wherein the first pass sub-composition further includes at least one filler and at least one activator.

26. The method of claim 25, wherein the at least one filler is selected from the group consisting of carbon black, silica, clay, calcium carbonate, and combinations thereof.

27. The method of claim 24, wherein the second pass sub-composition includes at least one curative and at least one accelerator.

28. The method of claim 20, wherein the rubber composition includes a component selected from the group consisting of natural rubber, butadiene rubber, ethylene propylene diene monomer rubber, and combinations thereof.

29. The method of claim 20, wherein the silane-grafted polyolefin composition and / or residues thereof is present in an amount from about 5 to 20 phr.

30. The method of claim 20, wherein the silane-grafted polyolefin composition and / or residues thereof includes a first silane-grafted styrene-ethylene-butylene-styrene polymer or elastomer and / or residues thereof.

31. The method of claim 20, wherein the silane-grafted polyolefin composition and / or residues thereof includes a silane-grafted polyethylene, a silane-grafted butylene, a silane-grafted styrene, or combinations thereof and / or residues thereof.

32. The method of claim 20, wherein the silane-grafted polyolefin composition and / or residues thereof include a silane-grafted low-density polyethylene, a silane-grafted high-density polyethylene, a silane-grafted ultrahigh molecular polyolefin, or combinations thereof and / or residues thereof.

33. The method of claim 20, wherein the silane-grafted polyolefin composition includes a first silane-grafted olefin polyolefin and / or residues thereof.

34. The method of claim 33, wherein the silane-grafted polyolefin composition further includes at least one additional silane-grafted polyolefin and / or residues thereof.

35. The method of claim 34, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin is selected from the group consisting of silane-grafted ethylene / a-olefin copolymers, silane-grafted olefin block copolymers, and combinations thereof.

36. The method of claim 34, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin is selected from the group consisting of silane-grafted olefin homopolymers, silane-grafted blends of homopolymers, copolymers of two or more olefins, silane- grafted blends of copolymers of two or more olefins, and a combination of silane-grafted olefin homopolymers blended with copolymers of two or more olefins.

37. The method of claim 34, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin includes a silane-grafted copolymer of an olefin selected from the group consisting of ethylene, propylene, 1 -butene, 1 -propene, 1 -hexene, 1 -octene, C9-16olefins, and combinations thereof.

38. The method of claim 34, wherein the first silane-grafted polyolefin and / or the at least one additional silane-grafted polyolefin includes a silane-grafted polyolefin selected from the group consisting of silane-grafted block copolymers, silane-grafted ethylene propylene diene monomer polymers, silane-grafted ethylene octene copolymers, silane-grafted ethylene butene copolymers, silane-grafted ethylene a-olefm copolymers, silane-grafted 1 -butene polymer with ethene, polypropylene homopolymers, silane-grafted methacrylate-butadiene-styrene polymers, silane- grafted polyolefin s with isotactic propylene units with random ethylene distribution, styrenic block copolymers, silane-grafted styrene ethylene butylene styrene copolymer, and combinations thereof.

39. The method of claim 20, wherein the silane-grafted polyolefin composition includes a silane-grafted polyolefin that is formed from a blend that includes a polyolefin and a silane crosslinker has the following formulaR1, R2, and R3are each independently H or C1-8alkyl.

40. The method of claim 39, wherein R1, R2, and R3are each methyl, ethyl, propyl, or butyl.

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