Tread compounds

Abstract

The present disclosure provides tread compounds prepared by a process comprising: a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0. 70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C to form a vulcanizable composition; (b) forming the vulcanizable composition of (a) into a tread; and ( c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

Description

TREAD COMPOUNDSBACKGROUNDField

[0001] The present disclosure provides tread compounds prepared by a process disclosed herein. The present disclosure also provides processes for preparing tread compounds.Background

[0002] In rubber compounds, e.g., treads for vehicle tires, sulfur is widely used to crosslink the rubber polymer and achieve a satisfactory stiffness and mechanical performance. According to solubility and molecular structure in rubber compositions, sulfur can be divided into two categories: soluble sulfur and insoluble sulfur. The type of sulfur used to prepare a rubber compound can have a considerable effect on the cure properties of the compound, leading to different mechanical performance. Insoluble sulfur is typically used in high sulfur loading tire structural components, such as belts, carcasses, body plies, etc., to avoid sulfur migration to the surface of the component, a phenomenon known as sulfur bloom, as well as other phase separation events occurring when sulfur is utilized above the solubility limit in the rubber compound. On the other hand, tread compounds are typically prepared using soluble sulfur, e.g., rubber maker's sulfur (RMS), due to the relatively low cost of RMS and low levels of sulfur employed in the formulations. However, there remains a need to improve the properties, e.g., strength and wear resistance, of tread compounds, which in turn affects tire wear and lifetime.BRIEF SUMMARY

[0003] The present disclosure provides a tread compound prepared by a process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 (9.2 Method A“Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b)at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0004] The present disclosure also provides a process for preparing a tread compound, the process comprising: a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 (9.2 Method A “Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0005] The typical specification range for insoluble sulfur heat stability at 105 °C (as measured as described in ISO 8332) is from about 0.75 to about 0.8; and the typical specification range for insoluble sulfur heat stability at 115 °C (as measured as described in ISO 8332) is from about 0.6 to about 0.64. See, e.g., Ignatz-Hoover, F., RubberWorld 258 5), August 2018. Applicant has unexpectedly discovered that insoluble sulfur having greater heat stability, e.g., having a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C, can be used to prepare tread compounds at high vulcanization temperatures, e.g., about 150 °C to about 220 °C, having improved properties, e.g., strength and elongation retention, relative to tread compounds prepared using insoluble sulfur having lower heat stability.

[0006] Additional embodiments and advantages of the disclosure will be set forth, in part, in the description that follows, and will flow from the description, or can be learned by practice of the disclosure. The embodiments and advantages of the disclosure will berealized and attained by means of the elements and combinations particularly pointed out in the appended claims.

[0007] It is to be understood that both the foregoing summary and the following detailed description are exemplary and explanatory only, and are not restrictive of the invention as claimed.BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Fig. l is a set of six scatter plots depicting the strength at break, elongation at break, and M100 for tread compounds 1-S12 (insoluble sulfur: cyclododecasulfur), 1-CP (insoluble sulfur: polymeric sulfur), 1-RMS (soluble sulfur: Ss), and 1-HD (insoluble sulfur: polymeric sulfur) when vulcanized at 150 °C (left) and 170 °C (right).

[0009] Fig. 2 is a set of nine scatter plots depicting the strength at break, elongation at break, and M100 for tread compounds 2-S12 (insoluble sulfur: cyclododecasulfur), 2-CP (insoluble sulfur: polymeric sulfur), 2-RMS (soluble sulfur: Ss), and 2-HD (insoluble sulfur: polymeric sulfur) when vulcanized at 130 °C (left), 150 °C (center), and 170 °C (right).

[0010] Fig. 3 is a set of nine scatter plots depicting the strength at break, elongation at break, and M100 for tread compounds 3-S12 (insoluble sulfur: cyclododecasulfur), 3-CP (insoluble sulfur: polymeric sulfur), 3 -RMS (soluble sulfur: Ss), and 3 -HD (insoluble sulfur: polymeric sulfur) when vulcanized at 130 °C (left), 150 °C (center), and 170 °C (right).

[0011] Fig. 4 is a set of six scatter plots depicting the strength at break, elongation at break, and Ml 00 for tread compounds 1-CP and 1-RMS before aging (top) and after aging (bottom).

[0012] Fig. 5 is a set of two bar graphs depicting the retained strength after aging (top) and retained elongation after aging (bottom) for tread compounds 1-CP and 1-RMS.

[0013] Fig. 6 is a scatter plot depicting a vulcanization cure history curve for tread compounds prepared using Cure Pro (solid line) or RMS (dashed line).

[0014] Fig. 7 is a line graph depicting a fatigue to failure test for tread compounds prepared using Cure Pro or RMS.DETAILED DESCRIPTIONDefinitions

[0015] The use of the terms "a", "an", "the", and similar referents in the context of describing the disclosure (especially in the context of the claims) are to be construed to cover both the singular and the plural, unless otherwise indicated. Recitation of ranges of values herein merely are intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended to better illustrate the disclosure and is not a limitation on the scope of the disclosure unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the disclosure.

[0016] The term "about" as used herein indicates the value of a given quantity varies by ± 5% of the value. For example, "about 100 nm" encompasses a range from 95 nm to 105 nm, inclusive.

[0017] The term "phr" as used herein refers to parts per hundred parts of rubber by weight. The parts by weight of individual components are based on 100 parts by weight of the total mass of the one or more elastomers present in the composition.

[0018] The term "insoluble sulfur" as used herein refers to sulfur that is insoluble in toluene. Insoluble sulfur is typically polymeric in nature, but certain non-polymeric allotropes of sulfur are also insoluble in toluene and therefore may be considered insoluble sulfur, e.g., cyclododecasulfur (S12). Insoluble sulfur is typically handled as a dispersion, e.g., a composition comprising insoluble sulfur and a carrier, e.g., a process oil, or other binder composition. Non-limiting examples of compositions comprising insoluble sulfur include Crystex™ Cure Pro and Crystex™ HD OT 20.

[0019] The term "total insoluble sulfur mass fraction" as used herein refers to the fraction by weight of insoluble sulfur present relative to the total amount of sulfur (soluble sulfur and insoluble sulfur), i.e., (mass of insoluble sulfur) / (mass of soluble sulfur and insoluble sulfur), present in a sample of insoluble sulfur. The total insoluble sulfur mass fraction may be measured by methods known in the art, e.g., the procedures described in ISO 8332, which is incorporated by reference herein in its entirety. In some embodiments, thetotal insoluble sulfur mass fraction is measured using the procedure described in Section 8 of ISO 8332, wherein toluene is the solvent used to dissolve the soluble sulfur. In some embodiments, the total insoluble sulfur mass fraction is measured after the insoluble sulfur has been heated for a specific period of time, e.g., 15 minutes, and a specific temperature, e.g., 105 °C or 115 °C, in mineral oil, as described in Section 9 of ISO 8332 (9.2 Method A “Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), wherein toluene is the solvent used to dissolve the soluble sulfur. Although Section 9 of ISO 8332 describes heating the insoluble sulfur at 105 °C, a person of skill in the art would understand that other temperatures, e.g., 115 °C or 120 °C, may also be used.

[0020] The term "elastomer" as used herein is a polymer with viscoelasticity (i.e., having both viscosity and elasticity) that typically has low intermolecular forces, low Young's modulus, and high failure strain. Elastomers can typically be cross-linked by heating in the presence of one or more cross-linking agents, a process called curing or vulcanization. Rubber is one type of elastomer. Non-limiting types of rubber include natural rubber (NR), synthetic rubber, and blends thereof. The term "natural rubber" as used herein refers to a naturally occurring elastomer that can be obtained from Hevea rubber trees. Non-limiting types of synthetic rubbers include unsaturated rubbers, saturated rubbers, rubbers with fluoro and fluoralkyl or fluoralkoxy substituent groups on the polymer chain (FKM), silicone rubbers (Q), and blends thereof. Non-limiting examples of unsaturated rubbers include polyisoprene rubber (IR), butyl rubber (IIR), polybutadiene rubber (BR), styrene-isoprene-butadiene rubber (SIBR), styrene butadiene rubber (SBR), nitrile butadiene rubber (NBR), chloroprene rubber (CR), ethylene propylene diene rubber (EPDM), and blends thereof. These unsaturated rubbers undergo cyclization and crosslinking reactions that lead to hardening of the aged part. Partial oxidation of vulcanizates leads to losses in performance when used in applications such as vehicle tire sidewalls. Saturated rubbers are rubbers that do not contain C=C unsaturation and include, but are not limited to, acrylic rubber (ACM), chlorinated polyethylene (CM), chlorosulfonated polyethylene (CSM), poly chloromethyloxiran (CO), ethylene-ethyl acrylate copolymer (EAM), epichlorohydrin rubber (ECO), ethylene propylene rubber (EPM), ethylenevinylacetate copolymer (EVM), rubbers with fluoro and fluoralkyl or fluoralkoxy substituent groups on the polymer chain (FKM), silicone rubber (Q), and blends thereof.

[0021] In some embodiments, the natural rubber comprises rubber derived from an alternative rubber plant. The term "natural rubber comprises rubber derived from an alternative rubber plant" as used herein refers to a naturally occurring elastomer that can be obtained from "non-Hevea" sources. In some embodiments, the alternative rubber plant is Parthenium argentatum (guayule) or Taraxacum kok-saghyz (Russian dandelion).

[0022] The term "recycled rubber" as used herein refers to an elastomer that has been reclaimed from scrap materials such as used tires.

[0023] The term "filler" as used herein is a substance that reinforces an elastomeric composition or gives an elastomeric composition other properties, including but not limited to expanding the volume of the composition. Non-limiting examples of fillers include carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, and fibers, and combinations thereof.

[0024] The term "plasticizer" as used herein refers to a processing aid used to reduce the viscosity, increase the plasticity, and / or extend the volume of a composition. Plasticizers facilitate the process of mixing and forming a composition comprising an elastomer before the composition is vulcanized. The term "process oil" may also be used to refer to a plasticizer. Non-limiting examples of plasticizers include mineral oils (paraffinic, aromatic, or naphthenic), organic esters, resins, waxes, ester plasticizers, and naturally derived oils, such as soybean oil, vegetable oil, or orange oil.

[0025] The term "rubber chemicals" as used herein refers to a compound or substance used to facilitate the vulcanization or the protection or performance of rubber, the rubber compound or the associated rubber article such as a tire or hose. Rubber chemicals include, but are not limited to, vulcanizing agents, accelerators, activators, and prevulcanization inhibitors and anti degradants including antiozonants, antioxidants, antifatigue agents, coupling agents, resins, performance resins or other additives known to one skilled in the art.

[0026] The term "vulcanization" as used herein refers to a process wherein cross-links are formed between elastomers to effect changes in the material properties of elastomers. In particular, vulcanization typically increases the rigidity and durability of elastomers. Vulcanization is carried out at room temperature or at elevated temperatures, depending on the nature of the elastomer(s), filler(s), and rubber chemical(s) being used. The term "curing" is also used in the art to describe this process.

[0027] The term "accelerator" as used herein refers to any substance that increases the kinetics of vulcanization. In some embodiments, accelerators enable vulcanization to be performed at lower temperatures and / or to use the vulcanization agent, e.g., sulfur, more efficiently. Non-limiting examples of accelerators include guanidines, thiazoles, sulfenamides, thiurams, dithiocarbamates, xanthates, and thiophosphates. Non-limiting examples of guanidines include diphenylguanidine (DPG). Non-limiting examples of thiazoles include 2mercaptobenzothiazole (MBT), zinc 2mercaptobenzothi azole (ZMBT), mercaptobenzothiazole disulfide (MBTS), and - / ert-butyl-2-benzothi azole sulfenimide (TBSI). Non-limiting examples of sulfenamides include N-Zc / V-buty 1-2- benzothiazylsulfenamide (TBBS), 7V-cyclohexylbenzothiazol-2-sulfenamide (CBS), dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-oxy di ethylene benzothiazole sulfenamide (OBTS), -oxy di ethylenethiocarbamyl- '-oxy di ethylene sulfenamide (OTOS), and thiocarbamyl sulfenamide. Non-limiting examples of thiurams include dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), and tetramethylthiuram monosulfide (TMTM). Non-limiting examples of dithiocarbamates include zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC), zinc dibutyl di thiocarbamate (ZDBC), nickel dibutyl dithiocarbamate (NDBC), sodium dibenzyldithiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), and zinc dibenzyldithiocarbamate (ZEBC).

[0028] The term "activator" as used herein refers to any substance that activates a vulcanizing agent and enables it to cross-link elastomers as described above. Activators may act via various mechanisms, including, but not limited to, by forming chemical complexes with accelerators or by coordinating to sulfur (when sulfur is used as a vulcanizing agent). Non-limiting examples of activators include metal oxides, acids, glycols and polyols, amines, amides, ureas, and metal complexes thereof. Non-limiting examples of metal oxides include zinc oxide, magnesium oxide, and lead oxide. Nonlimiting examples of acids include stearic acid and lauric acid. Non limiting examples of metal complexes include zinc ethylhexanoate.

[0029] The term "pre-vulcanization inhibitor" as used herein refers to compounds that delay the onset and / or the rate of vulcanization. These compounds are also referred to as "retarders." Non-limiting examples of pre-vulcanization inhibitors include TV-(cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, and phthalic anhydride.

[0030] As used herein, the term "strength at break" refers to the maximum amount of stress or pulling force that a rubber compound can withstand before breaking.

[0031] As used herein, the term "elongation at break" refers to the amount of stretching or deformation a rubber compound can undergo before it breaks during a tensile test. The term represents the elongation or lengthening of the rubber compound at the point of rupture.

[0032] As used herein, the term "M100" refers to the modulus at 100% elongation. The term is a measure of the stiffness or resistance to deformation of a rubber material at a specified elongation level.Tread Compounds and Processes for Preparing

[0033] The present disclosure provides a tread compound prepared by a process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 (9.2 Method A “Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0034] The present disclosure also provides a process for preparing a tread compound, the process comprising: a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 using toluene as a solvent, to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0035] In some embodiments, the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C as described in ISO 8332 using toluene as a solvent.

[0036] In some embodiments, the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.88 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 using toluene as a solvent.Vulcanizable Compositions

[0037] In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is from about 0.5 phr to about 18 phr. In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is from about 0.1 phr to about 0.5 phr, from about 0.1 phr to about 1 phr, from about 0.1 phr to about 1.5 phr, from about 0.1 phr to about 2 phr, from about 0.1 phr to about 2.5 phr, from about 0.1 phr to about 3 phr, from about 0.1 phr to about 5 phr, from about 0.5 phr to about 1 phr, from about 0.5 phr to about 1.5 phr, from about 0.5 phr to about 2 phr, from about 0.5 phr to about 2.5 phr, from about 0.5 phr to about 3 phr, from about 0.5 phr to about 5 phr, from about 1 phr to about 1.5 phr, from about 1 phr to about 2 phr, from about 1 phr to about 2.5 phr, from about 1 phr to about 3 phr, from about 1 phr to about 5 phr, from about 1.5 phr to about 2 phr, from about 1.5 phr to about 2.5 phr, from about 1.5 phr to about 3 phr, from about 1.5 phr to about 5 phr, from about 2 phr to about 2.5 phr, from about 2 phr to about 3 phr, from about 2 phr to about 5 phr, from about 2.5 phr to about 3 phr, from about 2.5 phr to about 5 phr, or from about 3 phr to about 5 phr. In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is from about 1 phr to about 10 phr, from about 1 phr to about 20 phr, from about 1 phr to about 30 phr, from about 1 phr to about 40 phr, from about 1 phr to about 50 phr, from about 1 phr to about 60 phr, from about 10 phr to about 20 phr, from about 10 phr to about 30 phr, from about 10 phr to about 40 phr, from about 10 phr to about 50 phr, from about 10 phr to about 60 phr, from about 20 phr to about 30 phr, from about 20 phr to about 40 phr, from about 20 phr to about 50 phr, from about 20 phr to about 60 phr, from about 30 phr to about 40 phr, from about 30 phr to about 50 phr, from about 30 phr to about 60 phr, from about 40 phrto about 50 phr, from about 40 phr to about 60 phr, or from about 50 phr to about 60 phr. In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is from about 2 phr to about 12 phr, from about 2 phr to about 14 phr, from about 2 phr to about 16 phr, from about 2 phr to about 18 phr, from about 4 phr to about 12 phr, from about 4 phr to about 14 phr, from about 4 phr to about 16 phr, from about 4 phr to about 18 phr, from about 6 phr to about 12 phr, from about 6 phr to about 14 phr, from about 6 phr to about 16 phr, from about 6 phr to about 18 phr, from about 8 phr to about 12 phr, from about 8 phr to about 14 phr, from about 8 phr to about 16 phr, from about 8 phr to about 18 phr, from about 10 phr to about 12 phr, from about 10 phr to about 14 phr, from about 10 phr to about 16 phr, from about 10 phr to about 18 phr, from about 12 phr to about 14 phr, from about 12 phr to about 16 phr, from about 12 phr to about 18 phr, from about 14 phr to about 16 phr, from about 14 phr to about 18 phr, or from about 16 phr to about 18 phr.

[0038] In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is about 1 phr. In some embodiments, the concentration of insoluble sulfur in the vulcanizable composition is about 0.1 phr, about 0.5 phr, about 1.5 phr, about 2 phr, about 2.5 phr, about 3 phr, about 3.5 phr, about 4 phr, about 4.5 phr, about 5 phr, about 6 phr, about 7 phr, about 8 phr, about 9 phr, about 10 phr, about 20 phr, about 30 phr, about 40 phr, about 50 phr, or about 60 phr.

[0039] In some embodiments, at least one elastomer is natural rubber (NR), polyisoprene rubber (IR), butyl rubber (IIR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), or a blend thereof. In some embodiments, at least one elastomer is natural rubber (NR), polybutadiene rubber (BR), and styrene butadiene rubber (SBR).

[0040] In some embodiments, the one or more elastomers further comprises recycled rubber.

[0041] In some embodiments, the concentration of each elastomer in the vulcanizable composition is independently from about 1 phr to about 100 phr. In some embodiments, the concentration of each elastomer in the vulcanizable composition is independently from about 1 phr to about 5 phr, from about 1 phr to about 10 phr, from about 1 phr to about 25 phr, from about 1 phr to about 50 phr, from about 1 phr to about 75 phr, from about 1 phr to about 100 phr, from about 5 phr to about 10 phr, from about 5 phr to about 25 phr, from about 5 phr to about 50 phr, from about 5 phr to about 75 phr, from about 5 phr to about 100 phr, from about 10 phr to about 25 phr, from about 10 phr to about 50phr, from about 10 phr to about 75 phr, from about 10 phr to about 100 phr, from about 25 phr to about 50 phr, from about 25 phr to about 50 phr, from about 25 phr to about 75 phr, from about 25 phr to about 100 phr, from about 50 phr to about 75 phr, from about 50 phr to about 100 phr, or from about 75 phr to about 100 phr.

[0042] In some embodiments, the concentration of each elastomer in the vulcanizable composition is independently about 5 phr, about 10 phr, about 15 phr, about 20 phr, about 25 phr, about 30 phr, about 35 phr, about 40 phr, about 45 phr, about 50 phr, about 55 phr, about 60 phr, about 65 phr, about 70 phr, about 75 phr, about 80 phr, about 85 phr, about 90 phr, about 95 phr, or about 100 phr.

[0043] In some embodiments, at least one filler is carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, fibers, or a combination thereof. In some embodiments, the at least one filler is derived from natural sources. For example, silica may be derived from rice husks.

[0044] In some embodiments, the at least one filler is carbon black. In some embodiments, the at least one filler is silica.

[0045] In some embodiments, the concentration of each filler in the vulcanizable composition is independently from about 1 phr to about 200 phr. In some embodiments, the concentration of each filler in the vulcanizable composition is independently from about 1 phr to about 25 phr, from about 1 phr to about 50 phr, from about 1 phr to about 75 phr, from about 1 phr to about 100 phr, from about 1 phr to about 125 phr, from about 1 phr to about 150 phr, from about 1 phr to about 175 phr, from about 1 phr to about 200 phr, from about 25 phr to about 50 phr, from about 25 phr to about 75 phr, from about 25 phr to about 100 phr, from about 25 phr to about 125 phr, from about 25 phr to about 150 phr, from about 25 phr to about 175 phr, from about 25 phr to about 200 phr, from about 50 phr to about 75 phr, from about 50 phr to about 100 phr, from about 50 phr to about 125 phr, from about 50 phr to about 150 phr, from about 50 phr to about 175 phr, from about 50 phr to about 200 phr, from about 75 phr to about 100 phr, from about 75 phr to about 125 phr, from about 75 phr to about 150 phr, from about 75 phr to about 175 phr, from about 75 phr to about 200 phr, from about 100 phr to about 125 phr, from about 100 phr to about 150 phr, from about 100 phr to about 175 phr, from about 100 phr to about 200 phr, from about 125 phr to about 150 phr, from about 125 phr to about 175 phr, fromabout 125 phr to about 200 phr, from about 150 phr to about 175 phr, from about 150 phr to about 200 phr, or from about 175 phr to about 200 phr.

[0046] In some embodiments, the concentration of each filler in the vulcanizable composition is independently about 5 phr, about 10 phr, about 15 phr, about 20 phr, about 25 phr, about 30 phr, about 35 phr, about 40 phr, about 45 phr, about 50 phr, about 55 phr, about 60 phr, about 65 phr, about 70 phr, about 75 phr, about 80 phr, about 85 phr, about 90 phr, about 95 phr, about 100 phr, about 105 phr, about 110 phr, about 115 phr, about 120 phr, about 125 phr, about 130 phr, about 135 phr, about 140 phr, about 145 phr, about 150 phr, about 155 phr, about 160 phr, about 165 phr, about 170 phr, about 175 phr, about 180 phr, about 185 phr, about 190 phr, about 195 phr, or about 200 phr.

[0047] In some embodiments, the at least one plasticizer is a mineral oil, an organic ester, a resin, a wax, an ester plasticizer, a naturally derived oil, or a combination thereof. In some embodiments, the mineral oil is naphthenic oil, paraffinic oil, or aromatic oil. In some embodiments, at least one plasticizer is a mineral oil and a wax.

[0048] In some embodiments, the concentration of each plasticizer in the vulcanizable composition is independently from about 1 phr to about 5 phr, from about 1 phr to about 10 phr, from about 1 phr to about 20 phr, from about 1 phr to about 30 phr, from about 1 phr to about 40 phr, from about 1 phr to about 50 phr, from about 5 phr to about 10 phr, from from about 5 phr to about 20 phr, from about 5 phr to about 30 phr, from about 5 phr to about 5 phr, from about 5 phr to about 50 phr, from from about 10 phr to about 20 phr, from about 10 phr to about 30 phr, from about 10 phr to about 40 phr, from about 10 phr to about 50 phr, from about 20 phr to about 30 phr, from about 20 phr to about 40 phr, from about 20 phr to about 50 phr, from about 30 phr to about 40 phr, from about 30 phr to about 50 phr, or from about 40 phr to about 50 phr.

[0049] In some embodiments, the concentration of each plasticizer in the vulcanizable composition is independently about 1 phr, about 5 phr, about 10 phr, about 15 phr, about 20 phr, about 25 phr, about 30 phr, about 35 phr, about 40 phr, about 45 phr, or about 50 phr.

[0050] In some embodiments, the vulcanizable composition comprises one or more rubber chemicals. In some embodiments, the one or more rubber chemicals comprise one or more accelerators, one or more activators, one or more pre-vulcanization inhibitors, or a combination thereof.

[0051] In some embodiments, one or more accelerators is a guanidine, a thiazole, a sulfenamide, a thiuram, a dithiocarbamate, a xanthate, a thiophosphate, or a combination thereof. In some embodiments, the guanidine is diphenylguanidine (DPG). In some embodiments, the thiazole is 2mercaptobenzothi azole (MBT), zinc 2mercaptobenzothiazole (ZMBT), mercaptobenzothiazole disulfide (MBTS), N-tert- butyl-2-benzothiazole sulfenimide (TBSI), or a combination thereof. In some embodiments, the sulfenamide is 7V-tert-butyl-2-benzothiazylsulfenamide (TBBS), N- cyclohexylbenzothiazol-2-sulfenamide (CBS), dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-ox diethylene benzothiazole sulfenamide (OBTS), N- oxy di ethylenethiocarbamyl- / ' / '-oxy di ethylene sulfenamide (OTOS), thiocarbamyl sulfenamide, or a combination thereof. In some embodiments, the sulfenamide is N- cyclohexylbenzothiazol-2-sulfenamide (CBS). In some embodiments, the thiuram is dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), tetramethylthiuram monosulfide (TMTM), or a combination thereof. In some embodiments, the dithiocarbamate is zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC), zinc dibutyl di thiocarbamate (ZDBC), nickel dibutyl dithiocarbamate (NDBC), sodium dibenzyldithiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), zinc dibenzyl dithiocarbamate (ZEBC), or a combination thereof.

[0052] In some embodiments, the one or more activators is a metal oxide, an acid, a metal complex, or a combination thereof. In some embodiments, the metal oxide is zinc oxide, magnesium oxide, lead oxide, or a combination thereof. In some embodiments, the acid is stearic acid, lauric acid, or a combination thereof. In some embodiments, the metal complex is zinc ethylhexanoate.

[0053] In some embodiments, the one or more pre-vulcanization inhibitors is 7V- (cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, phthalic anhydride, or a combination thereof.

[0054] In some embodiments, the concentration of each rubber chemical in the vulcanizable composition is independently from about 1 phr to about 5 phr, from about 1 phr to about 10 phr, from about 1 phr to about 20 phr, from about 1 phr to about 30 phr, from about 1 phr to about 40 phr, from about 1 phr to about 50 phr, from about 5 phr toabout 10 phr, from from about 5 phr to about 20 phr, from about 5 phr to about 30 phr, from about 5 phr to about 5 phr, from about 5 phr to about 50 phr, from from about 10 phr to about 20 phr, from about 10 phr to about 30 phr, from about 10 phr to about 40 phr, from about 10 phr to about 50 phr, from about 20 phr to about 30 phr, from about 20 phr to about 40 phr, from about 20 phr to about 50 phr, from about 30 phr to about 40 phr, from about 30 phr to about 50 phr, or from about 40 phr to about 50 phr.

[0055] In some embodiments, the concentration of each plasticizer in the vulcanizable composition is independently about 1 phr, about 2 phr, about 3 phr, about 4 phr, about 5 phr, about 6 phr, about 7 phr, about 8 phr, about 9 phr, about 10 phr, about 15 phr, about 20 phr, about 25 phr, about 30 phr, about 35 phr, about 40 phr, about 45 phr, or about 50 phr.

[0056] In some embodiments, the vulcanizable composition comprises an antidegradant. In some embodiments, the antidegradant is an antiozonant. Non-limiting examples of anti degradants include paraphenylenediamines (PPDs), trimethyl-dihydroquinolines (TMQs), phenolics, alkylated diphenylamines (DP As), diphenylamine-ketone condensates, and natural anti degradants. Non-limiting examples of PPDs include VJ-(4- methylpentan-2-yl)-7V4-phenylbenzene-l,4-diamine (6PPD), 7V-(l,4-dimethylpentyl)-A- phenyl-p-phenylenediamine (7PPD), 7V1-phenyl-A4-(propan-2-yl)benzene-l,4-diamine (IPPD), A '-di-.scc'-butyl- -phenylenediamine (44PD), A,A-bis(l,3-dimethylbutyl)-p- phenylenediamine (66PD), 7V,A'-bis(l,4-dimethylpentyl)-p-phenylenediamine (77PD), and N-N'-di octyl - -pheny I enedi amine (88PD). Non-limiting examples of TMQs include 2,2,4-trimethyl-l,2-dihydroquinoline and oligomers or polymers thereof.

[0057] In some embodiments, the vulcanizable composition comprises from about 1 to about 5 phr of an antidegradant. In some embodiments, the the vulcanizable composition comprises from about 0.001 phr to about 0.01 phr, from about 0.001 phr to about 0.1 phr, from about 0.001 phr to about 1 phr, from about 0.001 phr to about 5 phr, from about 0.001 phr to about 7.5 phr, from about 0.001 phr to about 10 phr, from about 0.01 phr to about 0.1 phr, from about 0.01 phr to about 1 phr, from about 0.01 phr to about 5 phr, from about 0.01 phr to about 7.5 phr, from about 0.01 phr to about 10 phr, from about 0.1 phr to about 1 phr, from about 0.1 phr to about 5 phr, from about 0.1 phr to about 7.5 phr, from about 0.1 phr to about 10 phr, from about 1 phr to about 7.5 phr, from about 1 phr to about 10 phr, from about 5 phr to about 7.5 phr, from about 5 phr to about 10 phr, or from about 7.5 phr to about 10 phr of an antidegradant.

[0058] In some embodiments, the vulcanizable composition comprises about 3 phr of an antidegradant. In some embodiments, the vulcanizable composition comprises about 0.001 phr, about 0.01 phr, about 0.1 phr, about 1 phr, about 2 phr, about 4 phr, about 5 phr, about 7.5 phr, or about 10 phr of an antidegradant.Process Variables

[0059] In some embodiments, the admixing in step (a) of a process disclosed herein is performed in multiple steps. In some embodiments, non-cure active chemicals, e.g., the filler and the elastomer, and optionally a coupling agent, anti degradant, and / or plasticizer, are mixed in a first step at a relatively high temperature, e.g, from about 120 °C to about 170 °C; and cure active chemicals, e.g., insoluble sulfur, are mixed in a second step at a relatively low temperature, e.g., from about 80 °C to about 130 °C. In some embodiments, the first step of the admixing in step (a) is performed with a mixing time of from about 1 minute to about 10 minutes. In some embodiments, the second step of the admixing in step (a) is performed with a mixing time of from about 0.5 minutes to about 2 minutes.

[0060] In some embodiments, the present disclosure provides a tread compound prepared by a process comprising:(a)(i) admixing at least one elastomer and at least one filler at a temperature of from about 120 °C to about 170 °C to give a partially finished compound;(a)(ii) admixing insoluble sulfur with the partially finished compound of (a)(i) of from about 80 °C to about 130 °C to form a vulcanizable composition; wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 using toluene as a solvent;(b) forming the vulcanizable composition of (a)(ii) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0061] In some embodiments, the admixing in step (a)(i) is performed at a temperature of from about 120 °C to about 170 °C. In some embodiments, the admixing in step (a)(i) is performed at a temperature of from about 120 °C to about 125 °C, from about 120 °C toabout 130 °C, from about 120 °C to about 140 °C, from about 120 °C to about 150 °C, from about 125 °C to about 130 °C, from about 125 °C to about 140 °C, from about 125 °C to about 150 °C, from about 130 °C to about 140 °C, from about 130 °C to about 150 °C, from about 140 °C to about 150 °C, from about 120 °C to about 160 °C, from about 130 °C to about 160 °C, from about 130 °C to about 170 °C, from about 140 °C to about 160 °C, from about 140 °C to about 170 °C, from about 150 °C to about 160 °C, from about 150 °C to about 170 °C, or from about 160 °C to about 170 °C.

[0062] In some embodiments, the admixing in step (a)(i) is performed at a temperature of about 120 °C. In some embodiments, the admixing in step (a)(i) is performed at a temperature of about 125 °C, about 130 °C, about 135 °C, about 140 °C, about 145 °C, about 150 °C, about 155 °C, about 160 °C, about 165 °C, about 170 °C, or about 175 °C.

[0063] In some embodiments, the admixing in step (a)(ii) is performed at a temperature of from about 80 °C to about 130 °C. In some embodiments, the admixing in step (a)(ii) is performed at a temperature of from about 80 °C to about 90 °C, from about 80 °C to about 100 °C, from about 80 °C to about 110 °C, from about 80 °C to about 120 °C, from about 90 °C to about 100 °C, from about 90 °C to about 110 °C, from about 90 °C to about 120 °C, from about 90 °C to about 130 °C, from about 100 °C to about 110 °C, from about 100 °C to about 120 °C, from about 100 °C to about 130 °C, from about 110 °C to about 120 °C, from about 110 °C to about 130 °C, or from about 120 °C to about 130 °C.

[0064] In some embodiments, the admixing in step (a)(ii) is performed at a temperature of about 90 °C. In some embodiments, the admixing in step (a)(ii) is performed at a temperature of about 80 °C, about 85 °C, about 95 °C, about 100 °C, about 105 °C, about 110 °C, about 115 °C, about 120 °C, about 125 °C, or about 130 °C.

[0065] In some embodiments, the vulcanizing in step (c) of a process disclosed herein is performed at a temperature of from about 170 °C to about 200 °C. In some embodiments, the vulcanizing is performed at a temperature of from about 140 °C to about 150 °C, from about 140 °C to about 160 °C, from about 140 °C to about 170 °C, from about 140 °C to about 180 °C, from about 140 °C to about 190 °C, from about 140 °C to about 200 °C, from about 140 °C to about 210 °C, from about 140 °C to about 220 °C, from about 150 °C to about 160 °C, from about 150 °C to about 170 °C, from about 150 °C to about 180 °C, from about 150 °C to about 190 °C, from about 150 °C to about 200 °C, from about 150 °C to about 210 °C, from about 150 °C to about 220 °C, from about from about 160°C to about 170 °C, from about 160 °C to about 180 °C, from about 160 °C to about 190 °C, from about 160 °C to about 200 °C, from about 160 °C to about 210 °C, from about 160 °C to about 220 °C, from about 170 °C to about 180 °C, from about 170 °C to about 190 °C, from about 170 °C to about 210 °C, from about 170 °C to about 220 °C, from about 180 °C to about 190 °C, from about 180 °C to about 200 °C, from about 180 °C to about 210 °C, from about 180 °C to about 220 °C, from about 190 °C to about 200 °C, from about 190 °C to about 210 °C, from about 190 °C to about 220 °C, from about 200 °C to about 210 °C, from about 200 °C to about 220 °C, or from about 210 °C to about 220 °C.

[0066] In some embodiments, the vulcanizing in step (c) of a process disclosed herein is performed at a temperature of about 170 °C. In some embodiments, the vulcanizing is performed at a temperature of about 140 °C, about 145 °C, about 150 °C, about 155 °C, about 160 °C, about 165 °C, about 175 °C, about 180 °C, about 185 °C, about 190 °C, about 195 °C, about 200 °C, about 205 °C, about 210 °C, about 215 °C, or about 220 °C.Properties of Tread Compounds

[0067] In some embodiments, the strength at break of a tread compound produced by a process disclosed herein is from about 10 MPa to about 25 MPa. In some embodiments, the strength at break of a tread compound produced by a process disclosed herein is from about 7.5 MPa to about 10 MPa, from about 7.5 MPa to about 15 MPa, from about 7.5 MPa to about 20 MPa, from about 7.5 MPa to about 25 MPa, from about 7.5 MPa to about 30 MPa, from about 10 MPa to about 15 MPa, from about 10 MPa to about 20 MPa, from about 10 MPa to about 30 MPa, from about 15 MPa to about 20 MPa, from about 15 MPa to about 25 MPa, from about 15 MPa to about 30 MPa, from about 20 MPa to about 25 MPa, from about 20 MPa to about 30 MPa, or from about 25 MPa to about 30 MPa.

[0068] In some embodiments, the strength at break of a tread compound produced by a process disclosed herein is about 15 MPa. In some embodiments, the strength at break of a tread compound produced by a process disclosed herein is about 7.5 MPa, about 10 MPa, about 20 MPa, about 25 MPa, or about 30 MPa.

[0069] In some embodiments, the strength at break of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is from about 7.5 MPa to about 10 MPa, from about 7.5MPa to about 15 MPa, from about 7.5 MPa to about 20 MPa, from about 7.5 MPa to about 25 MPa, from about 7.5 MPa to about 30 MPa, from about 10 MPa to about 15 MPa, from about 10 MPa to about 20 MPa, from about 10 MPa to about 25 MPa, from about 10 MPa to about 30 MPa, from about 15 MPa to about 20 MPa, from about 15 MPa to about 25 MPa, from about 15 MPa to about 30 MPa, from about 20 MPa to about 25 MPa, from about 20 MPa to about 30 MPa, or from about 25 MPa to about 30 MPa.

[0070] In some embodiments, the strength at break of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is about 15 MPa. In some embodiments, the strength at break of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is about 7.5 MPa, about 10 MPa, about 15 MPa, about 20 MPa, about 25 MPa, or about 30 MPa.

[0071] In some embodiments, the reduction in strength at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is less than 10%. In some embodiments, the reduction in strength at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is less than 40%, less than 35%, less than 30%, less than 25%, less than 20%, less than 15%, or less than 5%.

[0072] In some embodiments, the elongation at break of a tread compound produced by a process described herein is from about 200% to about 700%. In some embodiments, the elongation at break of a tread compound produced by a process described herein is from about 150% to about 200%, from about 150% to about 300%, from about 150% to about 400%, from about 150% to about 500%, from about 150% to about 600%, from about 150% to about 700%, from about 200% to about 300%, from about 200% to about 400%, from about 200% to about 500%, from about 200% to about 600%, from about 300% to about 400%, from about 300% to about 500%, from about 300% to about 600%, from about 300% to about 700%, from about 400% to about 500%, from about 400% to about 600%, from about 400% to about 700%, from about 500% to about 600%, from about 500% to about 700%, or from about 600% to about 700%.

[0073] In some embodiments, the elongation at break of a tread compound produced by a process described herein is about 400%. In some embodiments, the elongation at break of a tread compound produced by a process described herein is about 150%, about 200%,about 250%, about 300%, about 350%, about 450%, about 500%, about 550%, about 600%, about 650%, or about 700%.

[0074] In some embodiments, the elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is from about 200% to about 700%. In some embodiments, the elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is from about 110% to about 125%, from about 110% to about 150%, from about 110% to about 200%, from about 125% to about 150%, from about 125% to about 200%, from about 125% to about 300%, from about 150% to about 200%, from about 150% to about 300%, from about 150% to about 400%, from about 150% to about 500%, from about 150% to about 600%, from about 150% to about 700%, from about 200% to about 300%, from about 200% to about 400%, from about 200% to about 500%, from about 200% to about 600%, from about 300% to about 400%, from about 300% to about 500%, from about 300% to about 600%, from about 300% to about 700%, from about 400% to about 500%, from about 400% to about 600%, from about 400% to about 700%, from about 500% to about 600%, from about 500% to about 700%, or from about 600% to about 700%.

[0075] In some embodiments, the elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is about 400%. In some embodiments, the elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is about 110%, about 125%, about 150%, about 200%, about 250%, about 300%, about 350%, about 450%, about 500%, about 550%, about 600%, about 650%, or about 700%.

[0076] In some embodiments, the reduction in elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is less than 30%. In some embodiments, the reduction in elongation at break of a tread compound produced by a process described herein after the tread compound has been aged for about 7 days at about 77 °C relative to before aging is less than 50%, less than 45%, less than 40%, less than 35%, less than 25%, less than 20%, less than 15%, less than 10%, or less than 5%.

[0077] In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein is from about 2.0 MPa to about 5.8 MPa. In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein is from about 2.0 MPa to about 2.5 MPa, from about 2.0 MPa to about 3.0 MPa, from about 2.0 MPa to about 3.5 MPa, from about 2.0 MPa to about 4.0 MPa, from about 2.0 MPa to about 4.5 MPa, from about 2.0 MPa to about 5.0 MPa, from about 2.0 MPa to about 5.5 MPa, from about 2.0 MPa to about 6.0 MPa, from about 2.0 MPa to about 6.5 MPa, from about 2.0 MPa to about 7.0 MPa, from about 2.0 MPa to about 8.0 MPa, from about 2.5 MPa to about 3.0 MPa, from about 2.5 MPa to about 3.5 MPa, from about 2.5 MPa to about 4.0 MPa, from about 2.5 MPa to about 4.5 MPa, from about 2.5 MPa to about 5.0 MPa, from about 2.5 MPa to about 5.5 MPa, from about 2.5 MPa to about 6.0 MPa, from about 2.5 MPa to about 6.5 MPa, from about 2.5 MPa to about 7.0 MPa, from about 2.5 MPa to about 8.0 MPa, from about 3.0 MPa to about 3.5 MPa, from about 3.0 MPa to about 4.0 MPa, from about 3.0 MPa to about 4.5 MPa, from about 3.0 MPa to about 5.0 MPa, from about 3.0 MPa to about 5.5 MPa, from about 3.0 MPa to about 6.0 MPa, from about 3.0 MPa to about 6.5 MPa, from about 3.0 MPa to about 7.0 MPa, from about 3.0 MPa to about 8.0 MPa, from about 3.5 MPa to about 4.0 MPa, from about 3.5 MPa to about 4.5 MPa, from about 3.5 MPa to about 5.0 MPa, from about 3.5 MPa to about 5.5 MPa, from about 3.5 MPa to about 6.0 MPa, from about 3.5 MPa to about 6.5 MPa, from about 3.5 MPa to about 7.0 MPa, from about 3.5 MPa to about 8.0 MPa, from about 4.0 MPa to about 4.5 MPa, from about 4.0 MPa to about 5.0 MPa, from about 4.0 MPa to about 5.5 MPa, from about 4.0 MPa to about 6.0 MPa, from about 4.0 MPa to about 6.5 MPa, from about 4.0 MPa to about 7.0 MPa, from about 4.0 MPa to about 8.0 MPa, from about 4.5 MPa to about 5.0 MPa, from about 4.5 MPa to about 5.5 MPa, from about 4.5 MPa to about 6.0 MPa, from about 4.5 MPa to about 6.5 MPa, from about 4.5 MPa to about 7.0 MPa, from about 4.5 MPa to about 8.0 MPa, from about 5.0 MPa to about 5.5 MPa, from about 5.0 MPa to about 6.0 MPa, from about 5.0 MPa to about 6.5 MPa, from about 5.0 MPa to about 7.0 MPa, from about 5.0 MPa to about 8.0 MPa, from about 5.5 MPa to about 6.0 MPa, from about 5.5 MPa to about 6.5 MPa, from about 5.5 MPa to about 7.0 MPa, from about 5.5 MPa to about 8.0 MPa, from about 6.0 MPa to about 6.5 MPa, from about 6.0 MPa to about 7.0 MPa, from about 6.0 MPa to about 8.0 MPa, from about 6.5 MPa to about 7.0 MPa, from about 6.5 MPa to about 8.0 MPa, or from about 7.0 MPa to about 8.0 MPa.

[0078] In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein is about 5.0 MPa. In some embodiments, the M100 of a tread compound produced by a process disclosed herein is about 2.0 MPa, about 2.5 MPa, about 3.0 MPa, about 3.5 MPa, about 4.0 MPa, about 4.5 MPa, about 5.5 MPa, about 6.0 MPa, about 6.5 MPa, about 7.0 MPa, or about 8.0 MPa.

[0079] In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C is from about 2 MPa to about 16 MPa. In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C is from about 2 MPa to about 4 MPa, from about 2 MPa to about 6 MPa, from about 2 MPa to about 8 MPa, from about 2 MPa to about 10 MPa, from about 2 MPa to about 12 MPa, from about 2 MPa to about 14 MPa, from about 2 MPa to about 16 MPa, from about 4 MPa to about 6 MPa, from about 4 MPa to about 8 MPa, from about 4 MPa to about 10 MPa, from about 4 MPa to about 12 MPa, from about 4 MPa to about 14 MPa, from about 4 MPa to about 16 MPa, from about 6 MPa to about 8 MPa, from about 6 MPa to about 10 MPa, from about 6 MPa to about 12 MPa, from about 6 MPa to about 14 MPa, from about 6 MPa to about 16 MPa, from about 8 MPa to about 10 MPa, from about 8 MPa to about 12 MPa, from about 8 MPa to about 14 MPa, from about 8 MPa to about 16 MPa, from about 10 MPa to about 12 MPa, from about 10 MPa to about 14 MPa, from about 10 MPa to about 16 MPa, from about 12 MPa to about 14 MPa, from about 12 MPa to about 16 MPa, or from about 14 MPa to about 16 MPa.

[0080] In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C is about 5 MPa. In some embodiments, the Ml 00 of a tread compound produced by a process disclosed herein after the tread compound has been aged for about 7 days at about 77 °C is about 2 MPa, about 3 MPa, about 4 MPa, about 5 MPa, about 6 MPa, about 7 MPa, about 8 MPa, about 9 MPa, about 10 MPa, about 11 MPa, about 12 MPa, about 13 MPa, about 14 MPa, about 15 MPa, or about 16 MPa.Particular Embodiments

[0081] The disclosure also provides the following particular embodiments.

[0082] Embodiment 1. A tread compound prepared by a process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 using toluene as a solvent, to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0083] Embodiment 2. The tread compound of Embodiment 1, wherein the vulcanizing in step (c) is performed at a temperature of from about 170 °C to about 200 °C.

[0084] Embodiment 3. The tread compound of Embodiment 1 or 2, wherein at least one elastomer is natural rubber (NR), polyisoprene rubber (IR), butyl rubber (IIR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), or a blend thereof.

[0085] Embodiment 4. The tread compound of Embodiment 3, wherein the at least one elastomer is natural rubber (NR), polybutadiene rubber (BR), and styrene butadiene rubber (SBR).

[0086] Embodiment 5. The tread compound of Embodiment 4, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from 0 phr to about 100 phr.

[0087] Embodiment 6. The tread compound of Embodiment 5, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from about 5 phr to about 80 phr.

[0088] Embodiment 7. The tread compound of Embodiment 4, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from 0 phr to about 60 phr.

[0089] Embodiment 8. The tread compound of Embodiment 7, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from about 5 phr to about 25 phr.

[0090] Embodiment 9. The tread compound of Embodiment 4, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from 0 phr to about 100 phr.

[0091] Embodiment 10. The tread compound of Embodiment 9, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from about 15 phr to about 80 phr.

[0092] Embodiment 11. The tread compound of any one of Embodiments 1-10, wherein the at least one filler is carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, fibers, or a combination thereof.

[0093] Embodiment 12. The tread compound of Embodiment 11, wherein the at least one filler is carbon black.

[0094] Embodiment 13. The tread compound of Embodiment 12, wherein the concentration of carbon black in the vulcanizable composition is from 0 phr to about 100 phr.

[0095] Embodiment 14. The tread compound of Embodiment 11, wherein at least one filler is silica.

[0096] Embodiment 15. The tread compound of Embodiment 14, wherein the concentration of silica in the vulcanizable composition is from 0 phr to about 180 phr.

[0097] Embodiment 16. The tread compound of Embodiment 14, wherein the concentration of silica in the vulcanizable composition is from about 80 phr to about 160 phr.

[0098] Embodiment 17. The tread compound of any one of Embodiments 1-16, further comprising at least one plasticizer.

[0099] Embodiment 18. The tread compound of Embodiment 17, wherein the at least one plasticizer is a mineral oil, an organic ester, a resin, a wax, an ester plasticizer, a naturally derived oil, or a combination thereof.

[0100] Embodiment 19. The tread compound of Embodiment 18, wherein the mineral oil is naphthenic oil, paraffinic oil, or aromatic oil.

[0101] Embodiment 20. The tread compound of Embodiment 18 or 19, wherein at least one plasticizer is a mineral oil and a wax.

[0102] Embodiment 21. The tread compound of any one of Embodiments 18-20, wherein the concentration of at least one plasticizer in the vulcanizable composition is from about 5 phr to about 25 phr.

[0103] Embodiment 22. The tread compound of any one of Embodiments 1-21, wherein the composition comprises one or more rubber chemicals.

[0104] Embodiment 23. The tread compound of Embodiment 22, wherein the one or more rubber chemicals comprise one or more accelerators, one or more activators, one or more pre-vulcanization inhibitors, or a combination thereof.

[0105] Embodiment 24. The tread compound of Embodiment 23, wherein the one or more rubber chemicals comprise one or more accelerators.

[0106] Embodiment 25. The tread compound of Embodiment 24, wherein the one or more accelerators is a guanidine, a thiazole, a sulfenamide, a thiuram, a dithiocarbamate, a xanthate, a thiophosphate, or a combination thereof.

[0107] Embodiment 26. The tread compound of Embodiment 25, wherein the guanidine is diphenylguanidine (DPG).

[0108] Embodiment 27. The tread compound of Embodiment 25, wherein the thiazole is 2-mercaptobenzothiazole (MBT), zinc 2-mercaptobenzothiazole (ZMBT), mercaptobenzothiazole disulfide (MBTS), / ' / - / ert-butyl-2 -benzothiazole sulfenimide (TBSI), or a combination thereof.

[0109] Embodiment 28. The tread compound of Embodiment 25, wherein the sulfenamide is A- / c / 7-butyl-2-benzothiazylsulfenamide (TBBS), N- cyclohexylbenzothiazol-2-sulfenamide (CBS), dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-ox diethylene benzothiazole sulfenamide (OBTS), N- oxy di ethylenethiocarbamyl-ZC-oxy di ethylene sulfenamide (OTOS), thiocarbamyl sulfenamide, or a combination thereof.

[0110] Embodiment 29. The tread compound of Embodiment 28, wherein the sulfenamide is 7V-cyclohexylbenzothiazol-2-sulfenamide (CBS).[OHl] Embodiment 30. The tread compound of Embodiment 25, wherein the thiuram is dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), tetramethylthiuram monosulfide (TMTM), or a combination thereof.

[0112] Embodiment 31. The tread compound of Embodiment 25, wherein the dithiocarbamate is zinc dimethyldithiocarbamate (ZDMC), zinc di ethyl di thiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), nickel dibutyldithiocarbamate (NDBC), sodium dibenzyl di thiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), zinc dibenzyldithiocarbamate (ZEBC), or a combination thereof.

[0113] Embodiment 32. The tread compound of any one of Embodiments 24-31, wherein the concentration of the one or more accelerators in the vulcanizable composition is from about 1 phr to about 20 phr.

[0114] Embodiment 33. The tread compound of any one of Embodiments 23-32, wherein the one or more rubber chemicals comprise one or more activators.

[0115] Embodiment 34. The tread compound of Embodiment 33, wherein the one or more activators is a metal oxide, an acid, a metal complex, or a combination thereof.

[0116] Embodiment 35. The tread compound of Embodiment 34, wherein the metal oxide is zinc oxide, magnesium oxide, lead oxide, or a combination thereof.

[0117] Embodiment 36. The tread compound of Embodiment 34, wherein the acid is stearic acid, lauric acid, or a combination thereof.

[0118] Embodiment 37. The tread compound of Embodiment 34, wherein the metal complex is zinc ethylhexanoate.

[0119] Embodiment 38. The tread compound of any one of Embodiments 33-37, wherein the concentration of the one or more activators is from about 1 phr to about 10 phr.

[0120] Embodiment 39. The tread compound of any one of Embodiments 23-38, wherein the one or more rubber chemicals comprise one or more pre-vulcanization inhibitors.

[0121] Embodiment 40. The tread compound of Embodiment 39, wherein the one or more pre-vulcanization inhibitors is 7V-(cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, phthalic anhydride, or a combination thereof.

[0122] Embodiment 41. The tread compound of any one of Embodiments 1-40, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.1 phr to about 30 phr.

[0123] Embodiment 42. The tread compound of Embodiment 41, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.5 phr to about 2 phr.

[0124] Embodiment 43. The tread compound of any one of Embodiments 1-42, wherein the vulcanizing in step (c) is performed at about 170 °C.

[0125] Embodiment 44. The tread compound of any one of Embodiments 1-43, wherein the strength at break of the tread compound is from about 10 MPa to about 25 MPa.

[0126] Embodiment 45. The tread compound of any one of Embodiments 1-44, wherein the strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 10 MPa to about 25 MPa.

[0127] Embodiment 46. The tread compound of any one of Embodiments 1-45, wherein the reduction in strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 10%.

[0128] Embodiment 47. The tread compound of any one of Embodiments 1-46, wherein the elongation at break of the tread compound is from about 200% to about 700%.

[0129] Embodiment 48. The tread compound of any one of Embodiments 1-47, wherein the elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 200% to about 700%.

[0130] Embodiment 49. The tread compound of any one of Embodiments 1-48, wherein the reduction in elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 30%.

[0131] Embodiment 50. The tread compound of any one of Embodiments 1-49, wherein the M100 of the tread compound is from about 2.0 MPa to about 5.8 MPa.

[0132] Embodiment 51. The tread compound of any one of Embodiments 1-50, wherein the Ml 00 of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 4.0 to about 7.7 MPa.

[0133] Embodiment 52. A process for preparing a tread compound, the process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the sample for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 using toluene as a solvent, to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

[0134] Embodiment 53. The process of Embodiment 52, wherein the vulcanizing in step (c) is performed at a temperature of from about 170 °C to about 200 °C.

[0135] Embodiment 54. The process of Embodiment 52 or 53, wherein the at least one elastomer is natural rubber (NR), polyisoprene rubber (IR), butyl rubber (IIR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), or a blend thereof.

[0136] Embodiment 55. The process of Embodiment 54, wherein at least one elastomer is natural rubber (NR), polybutadiene rubber (BR), and styrene butadiene rubber (SBR).

[0137] Embodiment 56. The process of Embodiment 55, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from 0 phr to about 100 phr.

[0138] Embodiment 57. The process of Embodiment 56, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from about 5 phr to about 80 phr.

[0139] Embodiment 58. The process of Embodiment 55, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from 0 phr to about 60 phr.

[0140] Embodiment 59. The process of Embodiment 58, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from about 5 phr to about 25 phr.

[0141] Embodiment 60. The process of Embodiment 59, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from 0 phr to about 100 phr.

[0142] Embodiment 61. The process of Embodiment 60, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from about 15 phr to about 85 phr.

[0143] Embodiment 62. The process of any one of Embodiments 52-61, wherein the at least one filler is carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, fibers, or a combination thereof.

[0144] Embodiment 63. The process of Embodiment 62, wherein at least one filler is carbon black.

[0145] Embodiment 64. The process of Embodiment 63, wherein the concentration of carbon black in the vulcanizable composition is from 0 phr to about 100 phr.

[0146] Embodiment 65. The process of Embodiment 62, wherein at least one filler is silica.

[0147] Embodiment 66. The process of Embodiment 65, wherein the concentration of silica in the vulcanizable composition is from 0 phr to about 180 phr.

[0148] Embodiment 67. The process of Embodiment 66, wherein the concentration of silica in the vulcanizable composition is from about 80 phr to about 160 phr.

[0149] Embodiment 68. The process of any one of Embodiments 52-67, wherein step (a) further comprises admixing at least one plasticizer to form the vulcanizable composition.

[0150] Embodiment 69. The process of any Embodiment 68, wherein the at least one plasticizer is a mineral oil, an organic ester, a resin, a wax, an ester plasticizer, a naturally derived oil, or a combination thereof.

[0151] Embodiment 70. The process of Embodiment 69, wherein the mineral oil is naphthenic oil, paraffinic oil, or aromatic oil.

[0152] Embodiment 71. The process of Embodiment 69 or 70, wherein at least one plasticizer is a mineral oil and a wax.

[0153] Embodiment 72. The process of any one of Embodiments 69-71, wherein the concentration of at least one plasticizer in the vulcanizable composition is from about 0 phr to about 25 phr.

[0154] Embodiment 73. The process of any one of Embodiments 52-72, wherein the composition comprises one or more rubber chemicals.

[0155] Embodiment 74. The process of Embodiment 73, wherein the one or more rubber chemicals comprise one or more accelerators, one or more activators, one or more pre-vulcanization inhibitors, or a combination thereof.

[0156] Embodiment 75. The process of Embodiment 74, wherein one or more rubber chemicals comprise one or more accelerators.

[0157] Embodiment 76. The process of Embodiment 75, wherein the one or more accelerators is a guanidine, a thiazole, a sulfenamide, a thiuram, a dithiocarbamate, a xanthate, a thiophosphate, or a combination thereof.

[0158] Embodiment 77. The process of Embodiment 76, wherein the guanidine is diphenylguanidine (DPG).

[0159] Embodiment 78. The process of Embodiment 76, wherein the thiazole is2-mercaptobenzothiazole (MBT), zinc 2-mercaptobenzothiazole (ZMBT), mercaptobenzothiazole disulfide (MBTS), / ' / - / ert-butyl-2 -benzothiazole sulfenimide (TBSI), or a combination thereof.

[0160] Embodiment 79. The process of Embodiment 76, wherein the sulfenamide isA- / c77-butyl-2-benzothiazyl sulfenamide (TBBS), A-cyclohexylbenzothiazol-2- sulfenamide (CBS), dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-oxy di ethylene benzothiazole sulfenamide (OBTS), 7V-oxydiethylenethiocarbamyl-7V-oxy diethylene sulfenamide (OTOS), thiocarbamyl sulfenamide, or a combination thereof.

[0161] Embodiment 80. The process of Embodiment 79, wherein the sulfenamide is7V-cyclohexylbenzothiazol-2-sulfenamide (CBS).

[0162] Embodiment 81. The process of Embodiment 76, wherein the thiuram is dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), tetramethylthiuram monosulfide (TMTM), or a combination thereof.

[0163] Embodiment 82. The process of Embodiment 76, wherein the dithiocarbamate is zinc dimethyldithiocarbamate (ZDMC), zinc di ethyl di thiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), nickel dibutyldithiocarbamate (NDBC), sodium dibenzyl di thiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), zinc dibenzyldithiocarbamate (ZEBC), or a combination thereof.

[0164] Embodiment 83. The process of any one of Embodiments 75-82, wherein the concentration of the one or more accelerators in the vulcanizable composition is from about 1 phr to about 10 phr.

[0165] Embodiment 84. The process of any one of Embodiments 74-83, wherein the one or more rubber chemicals comprise one or more activators.

[0166] Embodiment 85. The process of Embodiment 84, wherein the one or more activators is a metal oxide, an acid, a metal complex, or a combination thereof.

[0167] Embodiment 86. The process of Embodiment 85, wherein the metal oxide is zinc oxide, magnesium oxide, lead oxide, or a combination thereof.

[0168] Embodiment 87. The process of Embodiment 85, wherein the acid is stearic acid, lauric acid, or a combination thereof.

[0169] Embodiment 88. The process of Embodiment 85, wherein the metal complex is zinc ethylhexanoate.

[0170] Embodiment 89. The process of any one of Embodiments 84-88, wherein the concentration of the one or more activators is from about 1 phr to about 10 phr.

[0171] Embodiment 90. The process of any one of Embodiments 74-89, wherein the one or more rubber chemicals comprise one or more pre-vulcanization inhibitors.

[0172] Embodiment 91. The process of Embodiment 90, wherein the one or more pre-vulcanization inhibitors is 7V-(cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, phthalic anhydride, or a combination thereof.

[0173] Embodiment 92. The process of any one of Embodiments 52-91, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.1 phr to about 20 phr.

[0174] Embodiment 93. The process of Embodiment 92, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.5 phr to about 2 phr.

[0175] Embodiment 94. The process of any one of Embodiments 52-93, wherein the vulcanizing in step (c) is performed at about 170 °C.

[0176] Embodiment 95. The process of any one of Embodiments 52-94, wherein the strength at break of the tread compound is from about 10 MPa to about 25 MPa.

[0177] Embodiment 96. The process of any one of Embodiments 52-95, wherein the strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 10 MPa to about 25 MPa.

[0178] Embodiment 97. The process of any one of Embodiments 52-96, wherein the reduction in strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 10%.

[0179] Embodiment 98. The process of any one of Embodiments 52-97, wherein the elongation at break of the tread compound is from about 200% to about 700%.

[0180] Embodiment 99. The process of any one of Embodiments 52-98, wherein the elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 200% to about 700%.

[0181] Embodiment 100. The process of any one of Embodiments 52-99, wherein the reduction in elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 30%.

[0182] Embodiment 101. The process of any one of Embodiments 52-100, wherein the M100 of the tread compound is from about 2.0 to about 5.8 MPa.

[0183] Embodiment 102. The process of any one of Embodiments 52-101, wherein the Ml 00 of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 4.0 to about 7.7 MPa.EXAMPLESEXAMPLE 1Preparation of Tread Compounds

[0184] Full season, summer, and winter passenger car radial (PCR) tire treads (Treads 1, 2, and 3, respectively) were prepared using methods known in the art using insoluble sulfur (cyclododecasulfur (S12), Crystex Cure Pro (CP), or Crystex HD OT 20 (HD)) or soluble sulfur (rubbermaker's sulfur (RMS)). The formulations used to prepare Treads 1, 2, and 3 are shown in Tables 1, 3, and 5, respectively. The mixing procedures used to prepare Treads 1, 2, and 3 are shown in Tables 2, 4, and 6, respectively.Table 1Table 2Table 3Table 4Table 5Table 6EXAMPLE 2Thermostability of Tread Compounds

[0185] The tread compounds prepared in Example 1 were tested for strength at break, elongation at break, and Ml 00 (stress value when compound stretched to 100% strain) using experimental procedures known in the art, such as ASTM D-412.

[0186] Fig. 1 shows the strength at break, elongation at break, and M100 for tread compounds 1 -S 12, 1-CP, 1-RMS, and 1-HD when vulcanized at 150 °C (left) and 170 °C (right). Fig. 2 shows the strength at break, elongation at break, and Ml 00 for tread compounds 2-S12, 2-CP, 2-RMS, and 2-HD when vulcanized at 130 °C (left), 150 °C(center), and 170 °C (right). Fig. 3 shows the strength at break, elongation at break, and M100 for tread compounds 3-S12, 3-CP, 3-RMS, and 3-HD when vulcanized at 130 °C (left), 150 °C (center), and 170 °C (right).

[0187] Select samples were also aged for 7 days at 77 °C. Fig. 4 shows the strength at break, elongation at break, and Ml 00 for tread compounds 1-CP and 1-RMS before aging (top) and after aging (bottom). As depicted in Fig. 5, the tread containing Cure Pro retained greater strength and elongation relative to the tread containing RMS.

[0188] Tread compounds prepared using Crystex Cure Pro and RMS had similar vulcanization cure history curves and dynamic fatigue properties, as shown in Figs. 6 and 7, respectively.

[0189] Having now fully described the methods, compounds, and compositions herein, it will be understood by those of skill in the art that the same can be performed within a wide and equivalent range of conditions, formulations, and other parameters without affecting the scope of the methods, compounds, and compositions provided herein or any embodiment thereof. All patents, patent applications, and publications cited herein, including standard test methods, e.g., ASTM and ISO methods and procedures, are fully incorporated by reference herein in their entirety.

Claims

WHAT IS CLAIMED IS:

1. A tread compound prepared by a process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the insoluble sulfur for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 (9.2 Method A “Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C; to provide the tread compound.

2. The tread compound of claim 1, wherein the vulcanizing in step (c) is performed at a temperature of from about 170 °C to about 200 °C.

3. The tread compound of claim 1 or 2, wherein the at least one elastomer is natural rubber (NR), polyisoprene rubber (IR), butyl rubber (HR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), or a blend thereof.

4. The tread compound of claim 3, wherein the at least one elastomer is natural rubber (NR), polybutadiene rubber (BR), and styrene butadiene rubber (SBR).

5. The tread compound of claim 4, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from 0 phr to about 100 phr.

6. The tread compound of claim 5, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from about 5 phr to about 25 phr.

7. The tread compound of claim 4, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from 0 phr to about 60 phr.

8. The tread compound of claim 7, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from about 5 phr to about 25 phr.

9. The tread compound of claim 4, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from 0 phr to about 100 phr.

10. The tread compound of claim 9, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from about 15 phr to about 85 phr.

11. The tread compound of any one of claims 1-10, wherein the at least one filler is carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, fibers, or a combination thereof.

12. The tread compound of claim 11, wherein at least one filler is carbon black.

13. The tread compound of claim 12, wherein the concentration of carbon black in the vulcanizable composition is from 0 phr to about 100 phr.

14. The tread compound of claim 11, wherein at least one filler is silica.

15. The tread compound of claim 14, wherein the concentration of silica in the vulcanizable composition is from 0 phr to about 180 phr.

16. The tread compound of claim 14, wherein the concentration of silica in the vulcanizable composition is from about 80 phr to about 160 phr.

17. The tread compound of any one of claims 1-16, further comprising at least one plasticizer.

18. The tread compound of claim 17, wherein the at least one plasticizer is a mineral oil, an organic ester, a resin, a wax, an ester plasticizer, a naturally derived oil, or a combination thereof.

19. The tread compound of claim 18, wherein the mineral oil is naphthenic oil, paraffinic oil, or aromatic oil.

20. The tread compound of claim 18 or 19, wherein the at least one plasticizer is a mineral oil and a wax.

21. The tread compound of any one of claims 18-20, wherein the concentration of at least one plasticizer in the vulcanizable composition is from about 0 phr to about 25 phr.

22. The tread compound of any one of claims 1-21, wherein the composition comprises one or more rubber chemicals.

23. The tread compound of claim 22, wherein the one or more rubber chemicals comprise one or more accelerators, one or more activators, one or more pre-vulcanization inhibitors, or a combination thereof.

24. The tread compound of claim 23, wherein the one or more rubber chemicals comprise one or more accelerators.

25. The tread compound of claim 24, wherein the one or more accelerators is a guanidine, a thiazole, a sulfenamide, a thiuram, a dithiocarbamate, a xanthate, a thiophosphate, or a combination thereof.

26. The tread compound of claim 25, wherein the guanidine is diphenylguanidine (DPG).

27. The tread compound of claim 25, wherein the thiazole is 2-mercaptobenzothiazole (MBT), zinc 2-mercaptobenzothiazole (ZMBT), mercaptobenzothiazole disulfide (MBTS), / ' / - / ert-butyl-2 -benzothiazole sulfenimide (TBSI), or a combination thereof.

28. The tread compound of claim 25, wherein the sulfenamide is 7V-tert-butyl-2- benzothiazylsulfenamide (TBBS), 7V-cyclohexylbenzothiazol-2-sulfenamide (CBS),dicyclohexyl-2-benzothiazolesulfenamide (DCBS), A -oxy di ethylene benzothiazole sulfenamide (OBTS), 7V-oxydiethylenethiocarbamyl-7V-oxy diethylene sulfenamide (OTOS), thiocarbamyl sulfenamide, or a combination thereof.

29. The tread compound of claim 28, wherein the sulfenamide is 7V-cyclohexylbenzothiazol- 2-sulfenamide (CBS).

30. The tread compound of claim 25, wherein the thiuram is dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), tetramethylthiuram monosulfide (TMTM), or a combination thereof.

31. The tread compound of claim 25, wherein the dithiocarbamate is zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC), zinc dibutyl di thiocarbamate (ZDBC), nickel dibutyl dithiocarbamate (NDBC), sodium dibenzyldithiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), zinc dibenzyl dithiocarbamate (ZEBC), or a combination thereof.

32. The tread compound of any one of claims 24-31, wherein the concentration of the one or more accelerators in the vulcanizable composition is from about 0.5 phr to about 20 phr.

33. The tread compound of any one of claims 23-32, wherein the one or more rubber chemicals comprise one or more activators.

34. The tread compound of claim 33, wherein the one or more activators is a metal oxide, an acid, a metal complex, or a combination thereof.

35. The tread compound of claim 34, wherein the metal oxide is zinc oxide, magnesium oxide, lead oxide, or a combination thereof.

36. The tread compound of claim 34, wherein the acid is stearic acid, lauric acid, or a combination thereof.

37. The tread compound of claim 34, wherein the metal complex is zinc ethylhexanoate.

38. The tread compound of any one of claims 33-37, wherein the concentration of the one or more activators is from about 1 phr to about 10 phr.

39. The tread compound of any one of claims 23-38, wherein the one or more rubber chemicals comprise one or more pre-vulcanization inhibitors.

40. The tread compound of claim 39, wherein the one or more pre-vulcanization inhibitors is 7V-(cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, phthalic anhydride, or a combination thereof.

41. The tread compound of any one of claims 1-40, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.1 phr to about 60 phr.

42. The tread compound of claim 41, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.5 phr to about 2 phr.

43. The tread compound of any one of claims 1-42, wherein the vulcanizing in step (c) is performed at about 170 °C.

44. The tread compound of any one of claims 1-43, wherein the strength at break of the tread compound is from about 10 MPa to about 25 MPa.

45. The tread compound of any one of claims 1-44, wherein the strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 10 MPa to about 25 MPa.

46. The tread compound of any one of claims 1-45, wherein the reduction in strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 10%.

47. The tread compound of any one of claims 1-46, wherein the elongation at break of the tread compound is from about 200% to about 700%.

48. The tread compound of any one of claims 1-47, wherein the elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 200% to about 700%.

49. The tread compound of any one of claims 1-48, wherein the reduction in elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 30%.

50. The tread compound of any one of claims 1-49, wherein the Ml 00 of the tread compound is from about 2.0 MPa to about 5.8 MPa.

51. The tread compound of any one of claims 1-50, wherein the Ml 00 of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 4.0 to about 7.7 MPa.

52. A process for preparing a tread compound, the process comprising:(a) admixing at least one elastomer, at least one filler, and insoluble sulfur, wherein the insoluble sulfur has a total insoluble sulfur mass fraction of at least 0.70 after heating the sample for 15 minutes at 115 °C or at least 0.87 after heating the insoluble sulfur for 15 minutes at 105 °C as described in ISO 8332 (9.2 Method A “Determination of thermal reversion of insoluble sulfur” using toluene as a solvent), to form a vulcanizable composition;(b) forming the vulcanizable composition of (a) into a tread; and(c) vulcanizing the vulcanizable composition of (b) at a temperature of from about 150 °C to about 220 °C;to provide the tread compound.

53. The process of claim 52, wherein the vulcanizing in step (c) is performed at a temperature of from about 170 °C to about 200 °C.

54. The process of claim 52 or 53, wherein the at least one elastomer is natural rubber (NR), polyisoprene rubber (IR), butyl rubber (HR), polybutadiene rubber (BR), styrene butadiene rubber (SBR), or a blend thereof.

55. The process of claim 54, wherein the at least one elastomer is natural rubber (NR), polybutadiene rubber (BR), and styrene butadiene rubber (SBR).

56. The process of claim 55, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from 0 phr to about 100 phr.

57. The process of claim 56, wherein the concentration of natural rubber (NR) in the vulcanizable composition is from about 5 phr to about 25 phr.

58. The process of claim 55, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from 0 phr to about 60 phr.

59. The process of claim 58, wherein the concentration of polybutadiene rubber (BR) in the vulcanizable composition is from about 5 phr to about 25 phr.

60. The process of claim 59, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from 0 phr to about 100 phr.

61. The process of claim 60, wherein the concentration of styrene butadiene rubber (SBR) in the vulcanizable composition is from about 85 phr to about 100 phr.

62. The process of any one of claims 52-61, wherein the at least one filler is carbon black, silica, kaolin, calcium silicate, talc, carbon nanotubes (CNT), carbon fibers (HCF), graphite, graphenes, aluminosilicates, starch, fibers, or a combination thereof.

63. The process of claim 62, wherein at least one filler is carbon black.

64. The process of claim 63, wherein the concentration of carbon black in the vulcanizable composition is from 0 phr to about 100 phr.

65. The process of claim 62, wherein the at least one filler is silica.

66. The process of claim 65, wherein the concentration of silica in the vulcanizable composition is from 0 phr to about 180 phr.

67. The process of claim 66, wherein the concentration of silica in the vulcanizable composition is from about 80 phr to about 160 phr.

68. The process of any one of claims 52-67, wherein step (a) further comprises admixing at least one plasticizer to form the vulcanizable composition.

69. The process of any claim 68, wherein the at least one plasticizer is a mineral oil, an organic ester, a resin, a wax, an ester plasticizer, a naturally derived oil, or a combination thereof.

70. The process of claim 69, wherein the mineral oil is naphthenic oil, paraffinic oil, or aromatic oil.

71. The process of claim 69 or 70, wherein the at least one plasticizer is a mineral oil and a wax.

72. The process of any one of claims 69-71, wherein the concentration of at least one plasticizer in the vulcanizable composition is from about 5 phr to about 25 phr.

73. The process of any one of claims 52-72, wherein the composition comprises one or more rubber chemicals.

74. The process of claim 73, wherein the one or more rubber chemicals comprise one or more accelerators, one or more activators, one or more pre-vulcanization inhibitors, or a combination thereof.

75. The process of claim 74, wherein the one or more rubber chemicals comprise one or more accelerators.

76. The process of claim 75, wherein the one or more accelerators is a guanidine, a thiazole, a sulfenamide, a thiuram, a dithiocarbamate, a xanthate, a thiophosphate, or a combination thereof.

77. The process of claim 76, wherein the guanidine is diphenylguanidine (DPG).

78. The process of claim 76, wherein the thiazole is 2-mercaptobenzothiazole (MBT), zinc 2-mercaptobenzothiazole (ZMBT), mercaptobenzothiazole disulfide (MBTS), N-tert- butyl-2-benzothiazole sulfenimide (TBSI), or a combination thereof.

79. The process of claim 76, wherein the sulfenamide is Af- / c / 7-butyl-2- benzothiazylsulfenamide (TBBS), 7V-cyclohexylbenzothiazol-2-sulfenamide (CBS), dicyclohexyl-2-benzothiazolesulfenamide (DCBS), N-oxy di ethylene benzothiazole sulfenamide (OBTS), 7V-oxydiethylenethiocarbamyl-7V-oxy diethylene sulfenamide (OTOS), thiocarbamyl sulfenamide, or a combination thereof.

80. The process of claim 79, wherein the sulfenamide is 7V-cyclohexylbenzothiazol-2- sulfenamide (CBS).

81. The process of claim 76, wherein the thiuram is dimethylcarbamothioic dithioperoxyanhydride (thiram), dipentamethylene thiuram tetrasulfide (DPIT), tetrabenzyl thiuram disulfide (TBzTD), tetraethylthiuram disulfide (TETD), tetramethylthiuram disulfide (TMTD), tetramethylthiuram monosulfide (TMTM), or a combination thereof.

82. The process of claim 76, wherein the dithiocarbamate is zinc dimethyldithiocarbamate (ZDMC), zinc diethyldithiocarbamate (ZDEC), zinc dibutyldithiocarbamate (ZDBC), nickel dibutyldithiocarbamate (NDBC), sodium dibenzyl di thiocarbamate (SBEC), sodium diethyldithiocarbamate (SDEC), tellurium diethyldithiocarbamate (TDEC), zinc dibenzyldithiocarbamate (ZEBC), or a combination thereof.

83. The process of any one of claims 75-82, wherein the concentration of the one or more accelerators in the vulcanizable composition is from about 0.5 phr to about 10 phr.

84. The process of any one of claims 74-83, wherein the one or more rubber chemicals comprise one or more activators.

85. The process of claim 84, wherein the one or more activators is a metal oxide, an acid, a metal complex, or a combination thereof.

86. The process of claim 85, wherein the metal oxide is zinc oxide, magnesium oxide, lead oxide, or a combination thereof.

87. The process of claim 85, wherein the acid is stearic acid, lauric acid, or a combination thereof.

88. The process of claim 85, wherein the metal complex is zinc ethylhexanoate.

89. The process of any one of claims 84-88, wherein the concentration of the one or more activators is from about 1 phr to about 10 phr.

90. The process of any one of claims 74-89, wherein the one or more rubber chemicals comprise one or more pre-vulcanization inhibitors.

91. The process of claim 90, wherein the one or more pre-vulcanization inhibitors is 7V- (cyclohexylthio)phthalimide (CTP), benzoic anhydride, salicylic anhydride, phthalic anhydride, or a combination thereof.

92. The process of any one of claims 52-91, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.1 phr to about 30 phr.

93. The process of claim 92, wherein the concentration of insoluble sulfur in the vulcanizable composition is from about 0.75 phr to about 2 phr.

94. The process of any one of claims 52-93, wherein the vulcanizing in step (c) is performed at about 170 °C.

95. The process of any one of claims 52-94, wherein the strength at break of the tread compound is from about 10 MPa to about 25 MPa.

96. The process of any one of claims 52-95, wherein the strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 10 MPa to about 25 MPa.

97. The process of any one of claims 52-96, wherein the reduction in strength at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 10%.

98. The process of any one of claims 52-97, wherein the elongation at break of the tread compound is from about 200% to about 700%.

99. The process of any one of claims 52-98, wherein the elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 200% to about 700%.

100. The process of any one of claims 52-99, wherein the reduction in elongation at break of the tread compound after the tread compound has been aged for 7 days at 77 °C relative to before aging is less than 30%.

101. The process of any one of claims 52-100, wherein the Ml 00 of the tread compound is from about 2.0 to about 5.8 MPa.

102. The process of any one of claims 52-101, wherein the M100 of the tread compound after the tread compound has been aged for 7 days at 77 °C is from about 4.0 to about 7.7 MPa.

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