Rubber vulcanization process using eutectic mixture

Abstract

1. A process for preparing a rubber vulcanizate, the process comprising: (i) providing a vulcanizable composition comprising a sulfur-based curative and a eutectic composition blend, the eutectic composition blend comprising a eutectic composition and an inert carrier; and (ii) heating the vulcanizable composition, thereby causing vulcanization.

Description

Technical Field

[0001] Embodiments of the present invention are directed to a process for preparing a vulcanizable composition by introducing a eutectic composition via an inert carrier.

Background Art

[0002] Zinc oxide is typically used in the sulfur vulcanization of rubber in combination with stearic acid. Zinc species and / or zinc oxide are thought to function as activators for sulfur crosslinking. It is also thought that zinc oxide and stearic acid form zinc species in situ and that the zinc species combine with zinc oxide to affect the rate and quality of the sulfur vulcanization process.

[0003] The zinc oxide conventionally used in the sulfur vulcanization process is characterized by a BET surface area of less than 10 m 2 / g and such zinc oxide may be referred to as micro zinc oxide. Generally, rubber vulcanization requires at least about 2 pbw of zinc oxide per 100 parts by weight (pbw) of rubber to effect the desired cure, particularly in tire technology. Nano zinc oxide having a BET surface area greater than 10 m 2 / g has also been proposed and it has been suggested that the use of nano zinc oxide can ultimately provide an improved process that requires only the input of less zinc oxide or other zinc species. However, the use of nano zinc oxide presents several difficulties including manufacturing problems and particle agglomeration.

Summary of the Invention

Problems to be Solved by the Invention

[0004] It is still desirable to reduce the concentration of zinc, particularly zinc oxide, used in the manufacture of tire components.

[0005] One or more embodiments of the present invention are a process for preparing a rubber vulcanizate, comprising: (i) providing a vulcanizable composition comprising a sulfur-based curing agent and a eutectic composition blend, the eutectic composition blend comprising a eutectic composition and an inert carrier; and (ii) heating the vulcanizable composition to thereby cause vulcanization.

Embodiments for Carrying Out the Invention

[0006] Embodiments of the present invention are based at least in part on the discovery of a process for preparing a vulcanizable composition comprising a eutectic composition. According to embodiments of the present invention, the eutectic composition is introduced in combination with an inert carrier. By doing so, the eutectic composition can be advantageously introduced into the composition as a solid blend, thereby eliminating the need for handling and supplying liquids. The prior art attempts to supply the eutectic composition in combination with components of a vulcanizable composition such as zinc oxide, whereas the present invention uses an inert material as a carrier. As a result, the present invention provides a mechanism by which the eutectic composition can be supplied in variable amounts from a stock blend of the carrier and the eutectic composition to various vulcanizable compositions without the need to otherwise change the components added to the composition. According to aspects of the present invention, the eutectic component can be pre-combined with an inert material and introduced into the composition as a solid blend. In certain embodiments, the inert material comprises materials not conventionally included in vulcanizable compositions, particularly those used in the manufacture of tires.

[0007] Vulcanizable composition As described above, a eutectic composition blend comprising a combination of a eutectic composition and a carrier is introduced into a vulcanizable composition for the production of sulfur-cured vulcanizates. In addition to the eutectic composition blend, the vulcanizable composition in one or more embodiments comprises a vulcanizable rubber, a filler, a sulfur-based curing agent, stearic acid, and a metal compound, such as zinc oxide or a zinc oxide derivative. Other optional components may also be included, such components including, but not limited to, process oil and / or extender oil, resins, waxes, curing accelerators, scorch inhibitors, anti-degradants, antioxidants, and other rubber compounding additives known in the art.

[0008] Eutectic mixture In one or more embodiments, a eutectic composition comprises a composition formed by combining two or more compounds that provides a resultant compound having a melting point lower than the melting point of each of the compounds being combined. For the purposes of this specification, a eutectic composition may be referred to as a eutectic mixture, a eutectic complex, or a eutectic pair. Each of the compounds being combined may also be referred to as a eutectic component, a eutectic constituent, a eutectic member, or a compound for forming a eutectic composition (e.g., a first compound and a second compound), respectively. Depending on the relative amounts of each eutectic component and the temperature at which observations are made, the present eutectic composition may be in the form of a liquid, which may be referred to as a eutectic liquid or a eutectic solvent. For a given composition, if the relative amounts of the respective components are at or near the lowest melting point of the eutectic mixture, the present composition may be referred to as a deep eutectic solvent, which may also be referred to as a DES (deep eutectic solvent).

[0009] Without being bound by any particular theory, it is believed that the present eutectic components combine, or otherwise react or interact to form a complex. Accordingly, any reference to a eutectic mixture, or a eutectic compound, a eutectic pair, or a eutectic complex includes compounds and reaction products or complexes formed by the combination of the constituents that result in a melting point lower than that of each of the respective constituents. For example, in one or more embodiments, a useful eutectic composition can be defined by the following Formula I,

Number

[0010] In one or more embodiments, useful eutectic compositions include compounds of an acid and a base, and examples of the acid and the base include Lewis acids and bases, or Bronsted acids and bases. In one or more embodiments, useful eutectic compositions include compounds of a quaternary ammonium salt and a metal halide (referred to as type I eutectic compositions), compounds of a quaternary ammonium salt and a metal halide hydrate (referred to as type II eutectic compositions), compounds of a quaternary ammonium salt and a hydrogen bond donor (referred to as type III eutectic compositions), or compounds of a metal halide hydrate and a hydrogen bond donor (referred to as type IV eutectic compositions). Instead of ammonium compounds, similar compounds of sulfonium or phosphonium can also be used, which can be easily envisioned by those skilled in the art.

[0011] Quaternary ammonium salt In one or more embodiments, the quaternary ammonium salt is solid at 20°C. In these or other embodiments, the metal halide and the hydrogen bond donor are solid at 20°C.

[0012] In one or more embodiments, a useful quaternary ammonium salt, which may also be referred to as an ammonium compound, may be defined by the following formula II, [Number] wherein each of R1, R2, R3, and R4 is independently hydrogen or a monovalent organic group, or alternatively, two of R1, R2, R3, and R4 are joined to form a divalent organic group, and Φ - is a counteranion. In one or more embodiments, at least one of R1, R2, R3, and R4, in other embodiments at least two, and in other embodiments at least three are not hydrogen.

[0013] In one or more embodiments, the counteranion (e.g., Φ - ) is selected from the group consisting of halide (X - ), nitrate (NO3 - ), tetrafluoroborate (BF4 - ), perchlorate (ClO4 - ), triflate (SO3CF3 - ), trifluoroacetate (COOCF3 - ). In one or more embodiments, Φ - is a halide ion, and in certain embodiments, it is a chloride ion.

[0014] In one or more embodiments, the monovalent organic group includes a hydrocarbyl group and the divalent organic group includes a hydrocarbylene group. In one or more embodiments, the monovalent and divalent organic groups include heteroatoms, such heteroatoms including, for example, but not limited to, oxygen and nitrogen, and / or halogen atoms. Accordingly, examples of the monovalent organic group can include an alkoxy group, a siloxy group, an ether group, and an ester group, and a carbonyl group or an acetyl substituent. In one or more embodiments, the hydrocarbyl group and the hydrocarbylene group include from 1 (or an appropriate minimum number) to about 18 carbon atoms, in other embodiments from 1 to about 12 carbon atoms, and in yet other embodiments from 1 to about 6 carbon atoms. The hydrocarbyl group and the hydrocarbylene group can be branched, cyclic, or linear. Exemplary types of hydrocarbyl groups include an alkyl group, a cycloalkyl group, an aryl group, and an alkylaryl group. Exemplary types of hydrocarbylene groups include an alkylene group, a cycloalkylene group, an arylene group, and an alkylarylene group. In certain embodiments, the hydrocarbyl group is selected from the group consisting of a methyl group, an ethyl group, an octadecyl group, a phenyl group, and a benzyl group. In certain embodiments, the hydrocarbyl group is a methyl group and the hydrocarbylene group is an ethylene or propylene group.

[0015] Useful types of ammonium compounds include secondary ammonium compounds, tertiary ammonium compounds, and quaternary ammonium compounds. In these or other embodiments, examples of ammonium compounds include ammonium halides, such as, but not limited to, ammonium chloride. In certain embodiments, the ammonium compound is a quaternary ammonium chloride. In certain embodiments, R1, R2, R3, and R4 are hydrogen and the ammonium compound is ammonium chloride. In one or more embodiments, the ammonium compound is asymmetric.

[0016] In one or more embodiments, the ammonium compound contains an alkoxy group and can be defined by the following formula III:

Number

[0017] Examples of ammonium compounds defined by formula III include, but are not limited to, N-ethyl-2-hydroxy-N,N-dimethylethanaminium chloride, 2-hydroxy-N,N,N-trimethylethanaminium chloride (also known as choline chloride), and N-benzyl-2-hydroxy-N,N-dimethylethanaminium chloride.

[0018] In one or more embodiments, the ammonium compound contains a halogen-containing substituent and can be defined by the following formula IV:

Number

[0019] Examples of ammonium compounds defined by formula III include, but are not limited to, 2-chloro-N,N,N-trimethylethanaminium (also called choline chloride), and 2-(chlorocarbonyloxy)-N,N,N-trimethylethanaminium chloride.

[0020] Hydrogen bond donor compound In one or more embodiments, hydrogen bond donor compounds, which may also be referred to as HBD (hydrogen-bond donor) compounds, include, but are not limited to, amines, amides, carboxylic acids, and alcohols. In one or more embodiments, the hydrogen bond donor compound includes a hydrocarbon chain component. The hydrocarbon chain component may have a carbon chain length of at least 2 carbon atoms, in other embodiments at least 3 carbon atoms, and in still other embodiments at least 5 carbon atoms. In these or other embodiments, the hydrocarbon chain component has a carbon chain length of less than 30 carbon atoms, in other embodiments less than 20 carbon atoms, and in still other embodiments less than 10 carbon atoms.

[0021] In one or more embodiments, useful amines include compounds defined by the following formula,

Number

[0022] Specific examples of useful amines include, but are not limited to, aliphatic amines, ethylenediamine, diethylenetriamine, aminoethylpiperazine, triethylenetetramine, tris(2-aminoethyl)amine, N,N'-bis-(2-aminoethyl)piperazine, piperazinylethylethylenediamine, and tetraethylenepentamine, propyleneamine, aniline, substituted aniline, and combinations thereof.

[0023] In one or more embodiments, useful amides include compounds defined by the following formula: [Number] wherein R is H, NH2, CH3, or CF3.

[0024] Specific examples of useful amides include, but are not limited to, urea, 1-methylurea, 1,1-dimethylurea, 1,3-dimethylurea, thiourea, urea, benzamide, acetamide, and combinations thereof.

[0025] In one or more embodiments, useful carboxylic acids include monofunctional, difunctional, and trifunctional organic acids. These organic acids can include alkyl acids, aryl acids, and mixed alkyl-aryl acids.

[0026] Specific examples of useful monofunctional carboxylic acids include, but are not limited to, aliphatic acids, phenylpropionic acid, phenylacetic acid, benzoic acid, and combinations thereof. Specific examples of difunctional carboxylic acids include, but are not limited to, oxalic acid, malonic acid, adipic acid, succinic acid, and combinations thereof. Specific examples of trifunctional carboxylic acids include citric acid, tricarballylic acid, and combinations thereof.

[0027] Types of alcohols include, but are not limited to, monools, diols, and triols. Specific examples of monools include aliphatic alcohols, phenol, substituted phenol, and mixtures thereof. Specific examples of diols include ethylene glycol, propylene glycol, resorcinol, substituted resorcinol, and mixtures thereof. Specific examples of triols include glycerol, benzenetriol, and mixtures thereof, but are not limited thereto.

[0028] Metal halide Examples of the types of metal halides include, but are not limited to, chlorides, bromides, iodides, and fluorides. In one or more embodiments, these metal halides include, but are not limited to, transition metal halides. One skilled in the art can easily envision the corresponding metal halide hydrates.

[0029] Specific examples of useful metal halides include, but are not limited to, aluminum chloride, aluminum bromide, aluminum iodide, zinc chloride, zinc bromide, zinc iodide, tin chloride, tin bromide, tin iodide, iron chloride, iron bromide, iron iodide, and combinations thereof. One skilled in the art can easily envision the corresponding metal halide hydrates. For example, aluminum chloride hexahydrate and copper chloride dihydrate correspond to the above halides.

[0030] Formation of eutectic complex One skilled in the art can select appropriate eutectic components in appropriate molar ratios to provide the desired eutectic composition. One skilled in the art will understand that the molar ratio of the first compound (e.g., Lewis base) included in the pair to the second compound (e.g., Lewis acid) included in the pair will vary based on the compounds selected. As will be understood by those skilled in the art, the suppression of the melting point of the eutectic solvent includes the eutectic point, which is the molar ratio of the first compound and the second compound that results in the minimum melting point suppression (i.e., deep eutectic solvent). However, the molar ratio of the first compound and the second compound can be varied in various ways and still result in suppression of the melting point of the eutectic solvent relative to the individual melting points of the first and second compounds, even if it is not the lowest melting point. Accordingly, the practice of one or more embodiments of the present invention includes forming a eutectic solvent at a molar ratio outside the eutectic point.

[0031] In one or more embodiments, the eutectic pair of compounds and the molar ratio of the first and second compounds of the pair are selected to produce a mixture having a melting point of less than 130°C, in other embodiments less than 110°C, in other embodiments less than 100°C, in other embodiments less than 80°C, in other embodiments less than 60°C, in other embodiments less than 40°C, in other embodiments less than 30°C. In these or other embodiments, the eutectic pair of compounds and the molar ratio of the compounds are selected to produce a mixture having a melting point of greater than 0°C, in other embodiments greater than 10°C, in other embodiments greater than 20°C, in other embodiments greater than 30°C, in other embodiments greater than 40°C.

[0032] In one or more embodiments, the eutectic pair of compounds and the molar ratio of the first and second compounds of the pair are selected to produce a eutectic solvent having the ability or performance to dissolve a desired metal compound, which may be referred to as solubility or dissolution power. As will be understood by those skilled in the art, this solubility can be quantified based on the weight of the metal compound dissolved in a given weight of the eutectic solvent over a specified time at a specified temperature and pressure when preparing a saturated solution. In one or more embodiments, the eutectic solvent of the present invention is selected to achieve a solubility of greater than 100 ppm, in other embodiments greater than 500 ppm, in other embodiments greater than 1000 ppm, in other embodiments greater than 1200 ppm, in other embodiments greater than 1400 ppm, in other embodiments greater than 1600 ppm when dissolving zinc oxide at a temperature of 50°C under atmospheric pressure over 24 hours. Here, ppm is measured on a solute weight to solvent weight basis.

[0033] In one or more embodiments, the eutectic solvent is formed by combining a first compound with a second compound in a suitable molar ratio to provide a solvent composition (i.e., a composition that is liquid at the desired temperature). The mixture can be mechanically stirred by using various techniques, including but not limited to solid-state mixing techniques or blending techniques. Generally speaking, the mixture is mixed or otherwise agitated until a visually homogeneous liquid is formed. Also, the mixture may be formed at an elevated temperature. For example, the present eutectic solvent may be formed by heating the mixture to a temperature above 50°C, above 70°C in other embodiments, or above 90°C in other embodiments. Mixing may be continued during heating of the mixture. Once the desired mixture is formed, the eutectic solvent can be cooled to room temperature. In one or more embodiments, the cooling of the present eutectic solvent may be performed at a controlled rate, such as less than 1°C / minute.

[0034] In one or more embodiments, useful eutectic compositions are commercially available. For example, deep eutectic solvents are commercially available from Scionix under the trade name Ionic Liquids. Useful eutectic compositions are also generally known as described in U.S. Patent Application Publication Nos. 2004 / 0097755(A1) and 2011 / 0207633(A1), which are incorporated herein by reference.

[0035] Inert carrier In one or more embodiments, the inert carrier, which may also be referred to as an inert material, is a solid particulate material that does not react with any other component of the vulcanizable composition or otherwise has a perceptible effect thereon. Examples of useful inert materials that may be used in the formation of eutectic compositions include, for example, calcium carbonate (CaCO3), wollastonite (CaSiO3), silicon dioxide (SiO2), and mixtures of two or more of these. In one or more embodiments, the inert carrier does not contain or substantially does not contain zinc oxide. In these or other embodiments, the inert carrier does not contain or substantially does not contain magnesium oxide. In these or other embodiments, the inert carrier does not contain any metal oxides.

[0036] In one or more embodiments, the inert material is a particulate material characterized by a median primary particle size (d50) of less than 200 nm, in other embodiments less than 150 nm, and in other embodiments less than 100 nm.

[0037] Vulcanizable rubber In one or more embodiments, the vulcanizable rubber, which may also simply be referred to as rubber or a vulcanizable elastomer, may include a polymer that can be vulcanized to form a composition having rubber or elastomeric properties. These elastomers may include natural rubber and synthetic rubber. Synthetic rubbers are typically obtained from the polymerization of conjugated diene monomers, the copolymerization of conjugated diene monomers with other monomers such as vinyl-substituted aromatic monomers, or the copolymerization of ethylene with one or more α-olefins and optionally one or more diene monomers.

[0038] Exemplary elastomers include natural rubber, synthetic polyisoprene, polybutadiene, polyisobutylene-co-isoprene, neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have numerous macromolecular structures, such as linear, branched, and star-shaped structures. These elastomers may also contain one or more functional units, which typically contain heteroatoms.

[0039] Filler As described above, the vulcanizable composition of the present invention may contain one or more fillers. These filler materials may include reinforcing fillers and non-reinforcing fillers. Exemplary fillers include carbon black, silica, and various inorganic fillers.

[0040] Useful carbon blacks include furnace black, channel black, and lamp black. More specific examples of carbon black include super abrasion furnace black, intermediate super abrasion furnace black, high abrasion furnace black, high speed extrusion furnace black, fine furnace black, semi-reinforcing furnace black, medium processing channel black, hard processing channel black, conductive channel black, and acetylene black.

[0041] In certain embodiments, the carbon black has a surface area (EMSA) of at least 20 m 2 / g, and in other embodiments, at least 35 m 2It may also be / g, and the surface area value can be determined by the cetyltrimethylammonium bromide (CTAB) technique according to ASTM standard D-1765. The carbon black may be in a pelletized form or in a non-pelletized cotton-like form. The preferred form of carbon black can depend on the type of mixing equipment used to mix the rubber compound.

[0042] Examples of suitable silica fillers include precipitated amorphous silica, wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), fumed silica, calcium silicate, aluminum silicate, magnesium silicate, and the like.

[0043] In one or more embodiments, the silica can be characterized by its surface area, and the surface area is a measure of its reinforcing properties. The Brunauer, Emmet and Teller (Brunauer, Emmet and Teller, "BET") method (described in J. Am. Chem. Soc., vol. 60, p. 309 et seq.) is recognized as a method for determining the surface area. The BET surface area of the silica is generally less than 450 m 2 / g. Useful ranges of the surface area include about 32 to about 400 m 2 / g, about 100 to about 250 m 2 / g, and about 150 to about 220 m 2 / g.

[0044] When using one or more silicas, the pH of the silica is generally about 5 to about 7, or a value slightly higher than 7, but in other embodiments, it is about 5.5 to about 6.8.

[0045] In one or more embodiments, when silica is used as a filler (alone or in combination with other fillers), a coupling agent and / or a shielding agent may be added to the rubber composition during mixing to enhance the interaction between the silica and the elastomer. Useful coupling agents and shielding agents are disclosed in U.S. Patent Nos. 3,842,111, 3,873,489, 3,978,103, 3,997,581, 4,002,594, 5,580,919, 5,583,245, 5,663,396, 5,674,932, 5,684,171, 5,684,172, 5,696,197, 6,608,145, 6,667,362, 6,579,949, 6,590,017, 6,525,118, 6,342,552, and 6,683,135, which are hereby incorporated by reference. Examples of sulfur-containing silica coupling agents include bis(trialkoxysilylorgano)polysulfide or mercapto-organoalkoxysilane. Types of bis(trialkoxysilylorgano)polysulfide include bis(trialkoxysilylorgano)disulfide and bis(trialkoxysilylorgano)tetrasulfide.

[0046] Other useful filler materials include various inorganic fillers and organic fillers. Examples of organic fillers include starch. Examples of inorganic fillers include silica, aluminum hydroxide, magnesium hydroxide, titanium oxide, boron nitride, iron oxide, mica, talc (magnesium hydrosilicate), and clay (aluminum hydrosilicate).

[0047] Resin As described above, the vulcanizable composition of the present invention may contain one or more resins. These resins include phenolic resins, and hydrocarbon resins such as alicyclic resins, aliphatic resins, aromatic resins, and terpene resins, and further combinations thereof. Useful resins are commercially available from various companies under various trade names, and such companies include, for example, Chemfax, Dow Chemical Company, Eastman Chemical Company, Idemitsu, Neville Chemical Company, Nippon, Polysat Inc., Resinall Corp., Pinova Inc., Yasuhara Chemical Co., Ltd., Arizona Chemical, and SI Group Inc., and Zeon.

[0048] In one or more embodiments, useful hydrocarbon resins may be characterized by a glass transition temperature (Tg) of about 30 to about 160 °C, in other embodiments about 35 to about 60 °C, and in other embodiments about 70 to about 110 °C. In one or more embodiments, useful hydrocarbon resins may also be characterized by having a softening point higher than its glass transition temperature (Tg). In certain embodiments, useful hydrocarbon resins have a softening point of about 70 to about 160 °C, in other embodiments about 75 to about 120 °C, and in other embodiments about 120 to about 160 °C.

[0049] In certain embodiments, one or more alicyclic resins are used in combination with one or more of aliphatic resins, aromatic resins, and terpene resins. In one or more embodiments, one or more alicyclic resins are used as the main weight component (e.g., a component exceeding 50% by weight) with respect to the total amount of the resin. For example, the resin used contains at least 55% by weight, in other embodiments at least 80% by weight, and in other embodiments at least 99% by weight of one or more alicyclic resins.

[0050] In one or more embodiments, the alicyclic resin includes both an alicyclic homopolymer resin and an alicyclic copolymer resin, and the alicyclic copolymer resin includes, optionally, those derived from alicyclic monomers combined with one or more other (non-alicyclic) monomers (however, the majority of the amounts of all monomers are alicyclic). Non-limiting examples of suitable and useful alicyclic resins include cyclopentadiene (“cyclopentadiene, CPD”) homopolymer or copolymer resins, and dicyclopentadiene (“dicyclopentadiene, DCPD”) homopolymer or copolymer resins, and combinations thereof. Non-limiting examples of alicyclic copolymer resins include CPD / vinyl aromatic copolymer resins, DCPD / vinyl aromatic copolymer resins, CPD / terpene copolymer resins, DCPD / terpene copolymer resins, CPD / aliphatic copolymer resins (e.g., CPD / C5 fraction copolymer resins), DCPD / aliphatic copolymer resins (e.g., DCPD / C5 fraction copolymer resins), CPD / aromatic copolymer resins (e.g., CPD / C9 fraction copolymer resins), DCPD / aromatic copolymer resins (e.g., DCPD / C9 fraction copolymer resins), CPD / aromatic-aliphatic copolymer resins (e.g., CPD / C5 and C9 fraction copolymer resins), DCPD / aromatic-aliphatic copolymer resins (e.g., DCPD / C5 and C9 fraction copolymer resins), CPD / vinyl aromatic copolymer resins (e.g., CPD / styrene copolymer resins), DCPD / vinyl aromatic copolymer resins (e.g., DCPD / styrene copolymer resins), CPD / terpene copolymer resins (e.g., limonene / CPD copolymer resins), and DCPD / terpene copolymer resins (e.g., limonene / DCPD copolymer resins). In certain embodiments, the alicyclic resin may include a hydrogenated form of one of the above alicyclic resins (i.e., a hydrogenated alicyclic resin). In other embodiments, the alicyclic resin excludes any hydrogenated alicyclic resins. In other words, the alicyclic resin is not hydrogenated.

[0051] In certain embodiments, one or more aromatic resins are used in combination with one or more of an aliphatic resin, an alicyclic resin, and a terpene resin. In one or more embodiments, one or more aromatic resins are used as a major weight component (e.g., a component exceeding 50% by weight) relative to the total amount of the resins. For example, the resin used comprises at least 55% by weight, in other embodiments at least 80% by weight, and in other embodiments at least 99% by weight of one or more aromatic resins.

[0052] In one or more embodiments, the aromatic resin includes both an aromatic homopolymer resin and an aromatic copolymer resin, and the aromatic copolymer resin includes those derived from combining one or more aromatic monomers with one or more other (non-aromatic) monomers (provided that the maximum amount of any type of monomer is aromatic). Non-limiting examples of useful aromatic resins include coumarone-indene resins and alkyl-phenol resins, as well as vinyl aromatic homopolymer or copolymer resins. For example, these resins are derived from one or more of alpha-methylstyrene, styrene, ortho-methylstyrene, meta-methylstyrene, para-methylstyrene, vinyltoluene, para(tert-butyl)styrene, methoxystyrene, chlorostyrene, hydroxystyrene, vinylmesitylene, divinylbenzene, vinylnaphthalene, or vinyl aromatic monomers obtained from a C9 fraction or a C8-C10 fraction. Non-limiting examples of vinyl aromatic copolymer resins include vinyl aromatic / terpene copolymer resins (e.g., limonene / styrene copolymer resin), vinyl aromatic / C5 fraction resins (e.g., C5 fraction / styrene copolymer resin), vinyl aromatic / aliphatic copolymer resins (e.g., CPD / styrene copolymer resin, and DCPD / styrene copolymer resin). Non-limiting examples of alkyl-phenol resins include p-tert-butylphenol-acetylene resins, alkylphenol-formaldehyde resins (e.g., alkylphenol-acetylene resins such as those having a low degree of polymerization). In certain embodiments, the aromatic resin may include a hydrogenated form of one of the above aromatic resins (i.e., a hydrogenated aromatic resin). In other embodiments, the aromatic resin excludes any hydrogenated aromatic resins. In other words, the aromatic resin is not hydrogenated.

[0053] In certain embodiments, one or more aliphatic resins are used in combination with one or more of an alicyclic resin, an aromatic resin, and a terpene resin. In one or more embodiments, one or more aliphatic resins are used as a major weight component (e.g., a component exceeding 50% by weight) relative to the total amount of the resin. For example, the resin used contains at least 55% by weight, in other embodiments at least 80% by weight, and in other embodiments at least 99% by weight of one or more aliphatic resins.

[0054] In one or more embodiments, the aliphatic resin includes both an aliphatic homopolymer resin and an aliphatic copolymer resin, and the aliphatic copolymer resin includes those derived from combining one or more aliphatic monomers with one or more other (non-aliphatic) monomers, provided that the maximum amount of any type of monomer is aliphatic. Non-limiting examples of useful aliphatic resins include homopolymer or copolymer resins of C5 fractions, C5 fraction / C9 fraction copolymer resins, C5 fraction / vinyl aromatic copolymer resins (e.g., C5 fraction / styrene copolymer resins), C5 fraction / alicyclic copolymer resins, and C5 fraction / C9 fraction / alicyclic copolymer resins, as well as combinations thereof. Non-limiting examples of cyclic aliphatic monomers include, but are not limited to, cyclopentadiene (“CPD”) and dicyclopentadiene (“DCPD”). In certain embodiments, the aliphatic resin may include a hydrogenated form of one of the above aliphatic resins (i.e., a hydrogenated aliphatic resin). In other embodiments, the aliphatic resin excludes any hydrogenated aliphatic resin. In other words, in such embodiments, the aliphatic resin is not hydrogenated.

[0055] In one or more embodiments, the terpene resin includes both terpene homopolymer resins and terpene copolymer resins, and the terpene copolymer resins include those derived from combining one or more terpene monomers with one or more other (non-terpene) monomers (provided that the maximum amount of any type of monomer is occupied by terpene). Non-limiting examples of useful terpene resins include α-pinene resin, β-pinene resin, limonene resin (e.g., L-limonene, D-limonene, and dipentene which is a racemic mixture of the L-isomer and D-isomer), β-farnesene, δ-3-carene, δ-2-carene, pinene-limonene copolymer resin, terpene phenol resin, and aromatic modified terpene resin, and combinations thereof. In certain embodiments, the terpene resin may include a hydrogenated form of one of the above terpene resins (i.e., hydrogenated terpene resin). In other embodiments, the terpene resin excludes any hydrogenated terpene resins. In other words, in such embodiments, the terpene resin is not hydrogenated.

[0056] Hardener Examples of rubber hardeners (also called vulcanizing agents) include sulfur-based vulcanization systems. The hardener is described in Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 20, pgs. 365-468, (3 rd Ed. 1982), particularly, Vulcanization Agents and Auxiliary Materials, pgs. 390-402, and A.Y. Coran, Vulcanization, Encyclopedia of Polymer Science and Engineering, (2 ndIt is described in (Ed.1989), and these are incorporated herein by reference. In one or more embodiments, the curing agent is sulfur. Examples of suitable sulfur vulcanizing agents include sulfur-donating vulcanizing agents such as "rubbermaker’s" soluble sulfur, amine disulfides, polymeric polysulfides, or sulfur olefin adducts, and insoluble polymeric sulfur. The vulcanizing agents may be used alone or in combination. A person skilled in the art will be able to easily select the amount of the vulcanizing agent to achieve the desired level of curing.

[0057] In one or more embodiments, the curing agent is used in combination with a curing accelerator. In one or more embodiments, an accelerator is used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanized rubber. Examples of accelerators include thiazole vulcanization accelerators (e.g., 2-mercaptobenzothiazole, dibenzothiazyl disulfide, and N-cyclohexyl-2-benzothiazyl-sulfenamide (CBS), etc.), and guanidine vulcanization accelerators (e.g., diphenylguanidine (DPG), etc.). A person skilled in the art will be able to easily select the amount of the curing accelerator to achieve the desired level of curing.

[0058] Other components Other components typically used in rubber compounding can also be added to the rubber composition. These include accelerators, activator promoters, oils, added plasticizers, waxes, scorch inhibitors, processing aids, zinc oxide, tackifying resins, reinforcing resins, fatty acids (e.g., stearic acid), peptizing agents, and anti-degradants, such as antioxidants and anti-ozone agents. In certain embodiments, the oils used include those conventionally used as extender oils. Useful oils or extenders that may be used include, but are not limited to, aromatic oils, paraffinic oils, naphthenic oils, vegetable oils (other than castor oil), low PCA oils (e.g., MES, TDAE, and SRAE, etc.), and heavy naphthenic oils. Suitable low PCA oils also include oils of various plant origins, such as those that can be obtained from vegetables, nuts, and seeds. Non-limiting examples include soybean oil, sunflower oil, safflower oil, corn oil, linseed oil, cottonseed oil, rapeseed oil, hemp oil, cashew oil, sesame oil, camellia oil, jojoba oil, macadamia nut oil, coconut oil, and palm oil.

[0059] Metal activators and organic acids As described above, the vulcanizable composition of the present invention contains a metal compound. In one or more embodiments, the metal compound is an activator (i.e., something that aids in the vulcanization or curing of the rubber). In other embodiments, the metal activator is a metal oxide. In certain embodiments, the metal activator is zinc oxide. In other embodiments, the metal activator is a zinc species formed in situ through the reaction or interaction between zinc oxide and an organic acid (e.g., stearic acid). In other embodiments, the metal compound is a magnesium compound such as magnesium hydroxide. In other embodiments, the metal compound is an iron compound such as iron oxide. In other embodiments, the metal compound is a cobalt compound such as cobalt carboxylate.

[0060] In one or more embodiments, the zinc oxide is less than 10 m 2 / g, in other embodiments less than 9 m 2 / g, in other embodiments less than 8 m 2It is unfunctionalized zinc oxide characterized by a BET surface area of less than 2 / g. In other embodiments, nanozinc oxide is used, which includes zinc oxide particles characterized by a BET surface area of more than 10 m

[0061] In one or more embodiments, the organic acid is a carboxylic acid. In certain embodiments, the carboxylic acid is a fatty acid including saturated and unsaturated fatty acids. In certain embodiments, saturated fatty acids such as stearic acid are used. Other useful acids include, but are not limited to, palmitic acid, arachidic acid, oleic acid, linoleic acid, and arachidonic acid.

[0062] Component amount Rubber In one or more embodiments, the vulcanizable composition includes a rubber component of at least 20% by weight, in other embodiments at least 30% by weight, and in other embodiments at least 40% by weight based on the total weight of the composition. In these or other embodiments, the vulcanizable composition includes a rubber component of up to 90% by weight, in other embodiments up to 70% by weight, and in other embodiments up to 60% by weight based on the total weight of the composition. In one or more embodiments, the vulcanizable composition includes a rubber component of about 20 to about 90% by weight, in other embodiments about 30 to about 70% by weight, and in other embodiments about 40 to about 60% by weight based on the total weight of the composition.

[0063] Eutectic composition In one or more embodiments, the vulcanizable composition comprises more than 0.005 parts by weight (pbw), in other embodiments more than 0.01 pbw, and in other embodiments more than 0.02 pbw of the eutectic composition per 100 parts by weight (phr) of rubber. In these or other embodiments, the vulcanizable composition comprises less than 3 pbw, in other embodiments less than 1 pbw, and in other embodiments less than 0.1 pbw of the eutectic composition phr. In one or more embodiments, the vulcanizable composition comprises from about 0.005 to about 3 pbw, in other embodiments from about 0.01 to about 1 pbw, and in other embodiments from about 0.02 to about 0.1 pbw of the eutectic composition phr.

[0064] In one or more embodiments, the amount of the eutectic solvent can be described based on the amount of the metal activator (such as zinc oxide) added. In one or more embodiments, the vulcanizable composition comprises more than 2 wt%, in other embodiments more than 3 wt%, and in other embodiments more than 5 wt% of the eutectic solvent based on the total weight of the eutectic solvent and the metal activator (e.g., zinc oxide) present in the vulcanizable composition. In these or other embodiments, the vulcanizable composition comprises less than 15 wt%, in other embodiments less than 12 wt%, and in other embodiments less than 10 wt% of the eutectic solvent based on the total weight of the eutectic solvent and the metal activator (e.g., zinc oxide) present in the vulcanizable composition. In one or more embodiments, the vulcanizable composition comprises from about 2 to about 15 wt%, in other embodiments from about 3 to about 12 wt%, and in other embodiments from about 5 to about 10 wt% of the eutectic solvent based on the total weight of the eutectic solvent and the metal activator (e.g., zinc oxide) present in the vulcanizable composition.

[0065] Carrier material In one or more embodiments, the amount of carrier material introduced in conjunction with the eutectic composition (i.e., the eutectic composition blend) can be described relative to the weight of the eutectic composition. In one or more embodiments, the weight ratio of the eutectic composition to the carrier exceeds at least 0.05:1, in other embodiments exceeds at least 0.01:1, and in other embodiments exceeds at least 0.2:1. In these or other embodiments, the weight ratio of the present eutectic composition to the carrier is less than 5:1, in other embodiments less than 3:1, and in other embodiments less than 1:1. In these or other embodiments, the weight ratio of the present eutectic composition to the carrier is from about 0.05:1 to about 5:1, in other embodiments from about 0.1:1 to about 3:1, and in other embodiments from about 0.2:1 to 1:1.

[0066] metal compound In one or more embodiments, the present vulcanizable composition comprises, per 100 parts by weight (phr) of rubber, more than 0.05 parts by weight (pbw), in other embodiments more than 0.1 pbw, and in other embodiments more than 0.15 pbw of a metal activator (such as zinc oxide). In these or other embodiments, the present vulcanizable composition comprises less than 2 pbw, in other embodiments less than 1 pbw, and in other embodiments less than 0.75 pbw of a metal activator (such as zinc oxide) in phr. In one or more embodiments, the present vulcanizable composition comprises from about 0.05 to about 2 pbw, in other embodiments from about 0.1 to about 1 pbw, and in other embodiments from about 0.15 to about 0.75 pbw of a metal activator (such as zinc oxide) in phr.

[0067] organic acid In one or more embodiments, the vulcanizable composition contains more than 0.5 parts by weight (pbw), in other embodiments more than 0.7 pbw, and in other embodiments more than 1.0 pbw of an organic acid (such as stearic acid) per 100 parts by weight (phr) of rubber. In these or other embodiments, the vulcanizable composition contains less than 5 pbw, in other embodiments less than 3 pbw, and in other embodiments less than 2 pbw of an organic acid (such as stearic acid) phr. In one or more embodiments, the vulcanizable composition contains from about 0.5 to about 5 pbw phr, in other embodiments from about 0.7 to about 3 pbw, and in other embodiments from about 1.0 to about 2 pbw of an organic acid (such as stearic acid).

[0068] Filler In one or more embodiments, the vulcanizable composition contains at least 0 parts by weight (pbw), in other embodiments at least 10 pbw, and in other embodiments at least 20 pbw of a filler per 100 parts by weight (phr) of rubber. In these or other embodiments, the vulcanizable composition contains a maximum of 200 pbw, in other embodiments a maximum of 100 pbw, and in other embodiments a maximum of 70 pbw of a filler phr. In one or more embodiments, the vulcanizable composition contains from about 0 to about 200 pbw phr, in other embodiments from about 10 to about 100 pbw, and in other embodiments from about 20 to about 70 pbw of a filler.

[0069] Carbon black In one or more embodiments, the vulcanizable composition contains at least 0 parts by weight (pbw), in other embodiments at least 10 pbw, and in other embodiments at least 20 pbw of carbon black per 100 parts by weight (phr) of rubber. In these or other embodiments, the vulcanizable composition contains a maximum of 200 pbw, in other embodiments a maximum of 100 pbw, and in other embodiments a maximum of 70 pbw of carbon black phr. In one or more embodiments, the vulcanizable composition contains from about 0 to about 200 pbw phr, in other embodiments from about 10 to about 100 pbw, and in other embodiments from about 20 to about 70 pbw of carbon black.

[0070] Silica In one or more embodiments, the vulcanizable composition comprises at least 5 parts by weight (pbw) per 100 parts by weight (phr) of rubber, at least 25 pbw in other embodiments, at least 50 pbw in other embodiments, and at least 70 pbw in other embodiments of silica. In these or other embodiments, the vulcanizable composition comprises up to 200 pbw in phr, up to 130 pbw in other embodiments, and up to 80 pbw in other embodiments of silica. In one or more embodiments, the vulcanizable composition comprises from about 5 to about 200 pbw in phr, from about 25 to about 130 pbw in other embodiments, and from about 50 to about 80 pbw in other embodiments of silica.

[0071] Filler ratio In one or more embodiments, the vulcanizable composition can be characterized by the ratio of the amount of a first filler to the amount of a second filler. In one or more embodiments, the ratio of the amount of carbon black silica to silica is about 1:1, about 10:1 in other embodiments, about 14:1 in other embodiments, and about 20:1 in other embodiments. In one or more embodiments, the ratio of the amount of carbon black to silica is about 1:5, about 1:10 in other embodiments, about 1:14 in other embodiments, and about 1:20 in other embodiments.

[0072] Silica coupling agent In one or more embodiments, the curable composition comprises at least 1 part by weight (pbw) of a silica coupling agent per 100 parts by weight of silica, at least 2 pbw in other embodiments, and at least 5 pbw in other embodiments. In these or other embodiments, the curable composition comprises a maximum of 20 pbw of a silica coupling agent per 100 parts by weight of silica, a maximum of 15 pbw in other embodiments, and a maximum of 10 pbw in other embodiments. In one or more embodiments, the curable composition comprises from about 1 to about 20 pbw, from about 2 to about 15 pbw in other embodiments, and from about 5 to about 10 pbw of a silica coupling agent per 100 parts by weight of silica.

[0073] Resin In one or more embodiments, the curable composition comprises more than 1 part by weight (pbw) per 100 parts by weight of rubber (phr), more than 15 pbw in other embodiments, more than 25 pbw in other embodiments, and more than 35 pbw in other embodiments of a resin (such as a hydrocarbon resin). In these or other embodiments, the curable composition comprises less than 150 pbw phr, less than 120 pbw in other embodiments, and less than 90 pbw in other embodiments of a resin (such as a hydrocarbon resin). In one or more embodiments, the curable composition comprises from about 1 to about 150 pbw phr, from about 15 to about 120 pbw in other embodiments, and from about 25 to about 90 pbw of a resin (such as a hydrocarbon resin).

[0074] Overview of the process According to an aspect of the invention, a eutectic composition is premixed with an inert carrier to form a eutectic composition blend. This blend is then added to the curable composition. In one or more embodiments, the present eutectic composition is prepared prior to combining the eutectic composition with the curable rubber. In other embodiments, the components of the present eutectic composition (i.e., the eutectic components) are introduced in the presence of the inert carrier. In other words, each of the eutectic components is introduced directly and separately with the inert carrier.

[0075] In one or more embodiments, the vulcanizable composition is prepared by mixing a vulcanizable rubber and a eutectic composition blend to form a masterbatch, and then subsequently adding a curing agent to the masterbatch. The preparation of the masterbatch may be carried out using one or more auxiliary mixing steps, in which, for example, after preparing a first mixture by mixing two or more components, one or more components may be sequentially added to the composition. Also, additional components can be added to the adjustment of the vulcanizable composition using prior art, and such additional components include, but are not limited to, carbon black, additional fillers, chemically treated inorganic oxides, silica, silica coupling agents, silica dispersants, processing oils, processing aids (such as zinc oxide and fatty acids, etc.), and anti-degradants (or antioxidants or anti-ozone degradation agents, etc.).

[0076] In one or more embodiments, the eutectic composition blend is introduced into the vulcanizable rubber as an initiating component in the formation of the rubber masterbatch. As a result, the eutectic composition blend is mixed with the rubber at high shear and high temperature. In one or more embodiments, the eutectic composition blend is mixed with the rubber at a minimum temperature exceeding 110 °C, in other embodiments exceeding 130 °C, and in other embodiments exceeding 150 °C. In one or more embodiments, the mixing at high shear and high temperature is carried out at a temperature of about 110 °C to about 170 °C.

[0077] In other embodiments, the eutectic composition blend is introduced into the vulcanizable rubber either sequentially or all at once together with a sulfur-based curing agent. Thereafter, the eutectic composition blend is mixed with the vulcanizable rubber at a maximum temperature below 110 °C, in other embodiments below 105 °C, and in other embodiments below 100 °C. In one or more embodiments, the mixing with the curing agent is carried out at a temperature of about 70 to about 110 °C.

[0078] Similar to the eutectic composition blend, zinc oxide and stearic acid can be added as starting components to the rubber masterbatch, and thus, these components will be subjected to high-temperature, high-shear mixing. Alternatively, zinc oxide and stearic acid can be added together with the sulfur-based curing agent, whereby only low-temperature mixing will be undergone.

[0079] In one or more embodiments, zinc oxide is introduced into the vulcanizable rubber separately and individually from the eutectic composition blend. In other embodiments, zinc oxide and the eutectic composition blend are pre-combined to form a zinc oxide masterbatch, which may include a solution in which zinc oxide is dissolved or otherwise dispersed in the eutectic composition blend. Thereafter, the zinc oxide masterbatch can be introduced into the vulcanizable rubber.

[0080] Mixing conditions In one or more embodiments, the vulcanizable composition is first prepared by mixing the vulcanizable rubber and the eutectic composition blend at a temperature of about 140 to about 180 °C, or in other embodiments about 150 to about 170 °C. In certain embodiments, after the first mixing, the composition (i.e., the masterbatch) is cooled to a temperature below 100 °C, or in other embodiments below 80 °C, and then the curing agent is added. In certain embodiments, mixing is continued at a temperature of about 90 to about 110 °C, or in other embodiments about 95 to about 105 °C, to prepare the final vulcanizable composition.

[0081] In one or more embodiments, the masterbatch mixing step, or one or two or more sub-steps of the masterbatch mixing step, can be characterized by the peak temperature that the composition reaches during mixing. This peak temperature can also be referred to as the dropping temperature. In one or more embodiments, the peak temperature of the composition during the masterbatch mixing step can be at least 140°C, in other embodiments at least 150°C, and in other embodiments at least 160°C. In these or other embodiments, the peak temperature of the composition during the masterbatch mixing step can be from about 140 to about 200°C, in other embodiments from about 150 to about 190°C, and in other embodiments from about 160 to about 180°C.

[0082] Final mixing step Following the masterbatch mixing step, a curing agent or curing agent system is introduced into the composition and mixing is continued to ultimately form a vulcanizable composition. This mixing step may be referred to as the final mixing step, the curing agent mixing step, or the product mixing step. The product obtained from this mixing step may also be referred to as a vulcanizable composition.

[0083] In one or more embodiments, the final mixing step can be characterized by the peak temperature that the composition reaches during final mixing. As will be recognized by those skilled in the art, this temperature can also be referred to as the final dropping temperature. In one or more embodiments, the peak temperature of the composition during final mixing can be at most 130°C, in other embodiments at most 110°C, and in other embodiments at most 100°C. In these or other embodiments, the peak temperature of the composition during final mixing can be from about 80 to about 130°C, in other embodiments from about 90 to about 115°C, and in other embodiments from about 95 to about 105°C.

[0084] Mixing equipment All components of the vulcanizable composition can be mixed using standard mixing equipment such as internal mixers (e.g., Banbury or Brabender mixers), extruders, kneaders, and two-roll mills. Mixing can be done alone or in parallel. As described above, the components can be mixed in a single stage or in multiple stages of two or more stages in other embodiments. For example, typically in a first stage (i.e., the mixing stage) that includes a rubber component and a filler, a masterbatch is prepared. Once the masterbatch is prepared, in the final mixing stage, a vulcanizing agent may be introduced into the masterbatch and mixed, and this final mixing stage is typically carried out at a relatively low temperature, thereby reducing the possibility that the timing of vulcanization becomes too early. It is also possible to employ an additional mixing stage, sometimes called a remill, between the masterbatch mixing stage and the final mixing stage.

[0085] Preparation of Tires This vulcanizable composition can be processed into tire parts according to ordinary tire manufacturing techniques, including standard rubber forming, shaping, and curing techniques. Typically, vulcanization is carried out by heating the vulcanizable composition in a mold, for example, which can be heated to about 140 °C to about 180 °C. The cured or crosslinked rubber composition may be referred to as a vulcanizate, and this vulcanizate generally contains a thermosetting three-dimensional polymer network. Other components such as fillers and processing aids may be uniformly dispersed throughout the crosslinked network. Pneumatic tires can be made as described in U.S. Patent Nos. 5,866,171, 5,876,527, 5,931,211, and 5,971,046, which are incorporated herein by reference.

[0086] Properties of Vulcanizates As described above, the vulcanizable composition of the present invention can be cured to prepare various tire parts. These tire parts include, but are not limited to, tire treads, tire sidewalls, belt skims, inner liners, and bead apexes.

[0087] According to an aspect of the present invention, a tire component, which may also be referred to as a vulcanizate, is characterized by advantageous curing properties, while containing only a relatively low concentration of a metal activator such as a zinc species.

[0088] In one or more embodiments, the present vulcanizate is characterized by containing less than 2 pbw of zinc, less than 1 phr in other embodiments, and less than 0.7 pbw in other embodiments, per 100 parts by weight of rubber.

[0089] In one or more embodiments, the tire component is a tire tread. As outlined herein, the tread contains a metal activator such as a zinc species only in a limited concentration, yet the tread is still characterized by a 300% modulus greater than 3 MPa, greater than 5 MPa in other embodiments, and greater than 7 MPa in other embodiments, when measured at room temperature according to ASTM standard D - 412.

[0090] To demonstrate the practice of the present invention, the following examples were prepared and tested. However, these examples should not be regarded as limiting the scope of the present invention. The claims define the present invention.

Examples

[0091] Several vulcanizable compositions were prepared by using the components and mixing order shown in the following table. All amounts are presented in parts by weight per 100 parts by weight of rubber, unless otherwise specified. The following table also provides the results of several analytical tests performed on the compositions and / or vulcanizates prepared from the compositions.

[0092] Formation of eutectic solvent A eutectic composition of choline chloride and urea was prepared by mixing 1 mole of choline chloride with 2 moles of urea at 100 °C to form a eutectic solvent. This eutectic solvent was considered to be a deep eutectic solvent, which may also be referred to as DES. The DES was cooled to room temperature under standard conditions.

[0093] Formation of Vulcanizable Composition Using the rubber formulations and mixing sequences provided in Table I, a vulcanizable composition was prepared. This rubber formulation was indicative of a rubber formulation useful for the manufacture of tire treads. As shown in Table I, the mixing procedure was a three-step mixing procedure including a masterbatch mixing step, a "remill mixing step", and a final mixing step. The various mixing steps were carried out in a Banbury mixer. During the preparation of the masterbatch, the mixer was operated at 75 rpm to reach a composition peak temperature of 160 °C. At that point, the composition was dropped from the mixer and cooled to below about 85 °C. At this point, the composition was reintroduced into the mixer with the components specified for the "remill stage", and mixing was continued at 75 rpm to achieve a composition peak temperature of about 160 °C. The composition was dropped from the mixer again and cooled to a temperature below about 50 °C. Next, the composition was reintroduced into the mixer again with the components specified for the "final mixing stage". These components included a DES, a DES blend, or a carrier as provided in Table II. As is apparent from Table II, in certain samples, the DES and the inert carrier were introduced separately. These samples are labeled as controls for comparison. In other samples, a preblend was made in accordance with the present invention in which the DES and the inert carrier were mixed prior to introducing the blend into the vulcanizable composition. These samples are labeled as inventions. The control sample contained only DES without adding an inert carrier.

Table 1

[0094] Rheometer measurements were performed using an MDR2000 operating at the temperatures specified in the table. The tensile mechanical properties (maximum stress, modulus of elasticity, elongation, and toughness) of the vulcanizate were measured by using the standard procedures described in ASTM-D412. The dynamic rheological properties (e.g., tan δ) of the vulcanizate were obtained from a temperature sweep test performed at 10 Hz over a range of about -80 °C to about 80 °C.

Table 2

[0095] The data in Table II indicate that the presence of the inert carrier had no appreciable effect on the curing characteristics, rheological properties, or tensile properties.

[0096] Various modifications and variations will be apparent to those skilled in the art without departing from the scope and spirit of the invention. The invention is not to be formally limited to the exemplary embodiments described herein. [1] A process for preparing a vulcanized rubber, wherein the process comprises: (i) providing a vulcanizable composition comprising a sulfur-based curing agent and a eutectic composition blend, wherein the eutectic composition blend comprises a eutectic composition and an inert carrier; (ii) heating the vulcanizable composition to thereby cause vulcanization. [2] The process according to [1], wherein the vulcanizable composition contains a metal compound, and the metal compound is zinc oxide. [3] The process according to [1] or [2], wherein the vulcanizable composition provides a vulcanizable rubber and is formed by introducing a sulfur-based curing agent and a eutectic composition blend into the vulcanizable rubber. [4] The process according to any one of [1] to [3], wherein the zinc oxide and the eutectic composition blend are introduced into the vulcanizable rubber separately and individually. [5] The process according to any one of [1] to [4], wherein the zinc oxide and the eutectic composition blend are pre-combined before being introduced into the vulcanizable composition. [6] The process according to any one of [1] to [5], wherein the vulcanizable composition contains less than 2 pbw of zinc oxide per 100 pbw of rubber. [7] The process according to any one of [1] to [6], wherein the eutectic composition is formed by combining choline chloride and urea. [8] The process according to any one of [1] to [7], wherein the vulcanizable composition contains about 0.005 to about 3 pbw of the eutectic composition per 100 pbw of rubber. [9] The process according to any one of [1] to [8], wherein the vulcanizable composition further contains a reinforcing filler, a resin, and an oil.

[10] The process according to any one of [1] to [9], wherein the resin is selected from the group consisting of a phenolic resin, a hydrocarbon resin, and combinations thereof.

[11] The process according to any one of [1] to

[10] , wherein the resin is selected from the group consisting of an alicyclic resin, an aliphatic resin, an aromatic resin, a terpene resin, and combinations thereof.

[12] The process according to any one of [1] to

[11] , wherein the resin is present in an amount greater than 15 parts by weight of resin per 100 parts by weight of rubber.

[13] The process according to any one of [1] to

[12] , wherein the resin is present in an amount greater than 25 parts by weight of resin per 100 parts by weight of rubber.

[14] The process according to any one of [1] to

[13] , wherein the resin is present in an amount greater than 35 parts by weight of resin per 100 parts by weight of rubber.

[15] The process according to any one of [1] to

[14] , wherein the reinforcing filler is silica.

[16] The process according to any one of [1] to

[15] , wherein the silica is present in an amount of at least 25 parts by weight of silica per 100 parts by weight of rubber.

[17] The process according to any one of [1] to

[16] , wherein the silica is present in an amount of at least 50 parts by weight of silica per 100 parts by weight of rubber.

[18] The process according to any one of [1] to

[17] , wherein the silica is present in an amount of at least 70 parts by weight of silica per 100 parts by weight of rubber.

[19] The process according to any one of [1] to

[18] , wherein the oil is selected from the group consisting of aromatic oils, paraffinic oils, naphthenic oils, vegetable oils other than castor oil, and low-PCA oils containing heavy naphthenic oils.

[20] The process according to any one of [1] to

[19] , wherein the oil is an oil of plant origin.

[21] The process according to any one of [1] to

[20] , wherein the eutectic composition is defined by the formula Cat+X-zY, wherein Cat+ is a cation, X- is a counter anion (e.g., a Lewis base), and z represents the number of Y molecules (e.g., a Lewis acid or a Bronsted acid) that interact with the counter anion.

[22] The process according to any one of [1] to

[21] , wherein Cat+ is an ammonium cation, a phosphonium cation, or a sulfonium cation, and X- is a halide ion.

[23] The process according to any one of [1] to

[22] , wherein the eutectic composition is selected from the group consisting of type I, type II, type III, and type IV eutectic compositions.

[24] The process according to any one of [1] to

[23] , wherein the eutectic composition is formed by combining an ammonium compound with a metal halide, a metal halide hydrate, or a hydrogen bond donor.

[25] The ammonium compound may be defined by formula II,

Number

[24] .

[26] The process according to any one of [1] to

[25] , wherein the ammonium compound is selected from the group consisting of N-ethyl-2-hydroxy-N,N-dimethylethanaminium chloride, 2-hydroxy-N,N,N-trimethylethanaminium chloride (also known as choline chloride), and N-benzyl-2-hydroxy-N,N-dimethylethanaminium chloride.

[27] The process according to any one of [1] to

[26] , wherein the ammonium compound is selected from the group consisting of 2-chloro-N,N,N-trimethylethanaminium (also called chlorocholine chloride) and 2-(chlorocarbonyloxy)-N,N,N-trimethylethanaminium chloride.

[28] The process according to any one of [1] to

[27] , wherein the hydrogen bond donor is selected from the group consisting of amines, amides, carboxylic acids, and alcohols.

[29] The process according to any one of [1] to

[28] , wherein the hydrogen bond donor is selected from the group consisting of aliphatic amines, ethylenediamine, diethylenetriamine, aminoethylpiperazine, triethylenetetramine, tris(2-aminoethyl)amine, N,N'-bis-(2-aminoethyl)piperazine, piperazinoethylethylenediamine, and tetraethylenepentamine, propyleneamine, aniline, substituted aniline, and combinations thereof.

[30] The process according to any one of [1] to

[29] , wherein the hydrogen bond donor is selected from the group consisting of urea, 1-methylurea, 1,1-dimethylurea, 1,3-dimethylurea, thiourea, urea, benzamide, acetamide, and combinations thereof.

[31] The process according to any one of [1] to

[30] , wherein the hydrogen bond donor is selected from the group consisting of phenylpropionic acid, phenylacetic acid, benzoic acid, oxalic acid, malonic acid, adipic acid, succinic acid, citric acid, tricarballylic acid, and combinations thereof.

[32] The process according to any one of [1] to

[31] , wherein the hydrogen bond donor is selected from the group consisting of aliphatic alcohols, phenol, substituted phenol, ethylene glycol, propylene glycol, resorcinol, substituted resorcinol, glycerol, benzenetriol, and mixtures thereof.

[33] The process according to any one of [1] to

[32] , wherein the metal halide is selected from the group consisting of aluminum chloride, aluminum bromide, aluminum iodide, zinc chloride, zinc bromide, zinc iodide, tin chloride, tin bromide, tin iodide, iron chloride, iron bromide, iron iodide, and combinations thereof.

[34] The process according to any one of [1] to

[33] , wherein the eutectic composition is provided together with a carrier.

[35] The process according to any one of [1] to

[34] , wherein the carrier is solid.

[36] The process according to any one of [1] to

[35] , wherein the carrier is zinc oxide.

[37] The process according to any one of [1] to

[36] , wherein the carrier is a eutectic member.

[38] The process according to any one of [1] to

[37] , wherein the eutectic composition is a eutectic solvent under standard conditions.

[39] The process according to any one of [1] to

[38] , wherein the eutectic composition is a deep eutectic solvent.

[40] The process according to any one of [1] to

[39] , wherein the inert carrier is selected from the group consisting of calcium carbonate, wollastonite, silicon dioxide, and mixtures of two or more thereof.

[41] The process according to any one of [1] to

[40] , wherein the median diameter of the inert carrier is less than 200 nm.

[42] The process according to any one of [1] to

[41] , wherein the weight ratio of the eutectic composition to the carrier is from about 0.05:1 to about 5:1.

[43] A vulcanizate prepared from the process according to any one of [1] to

[42] .

Claims

1. A process for preparing a vulcanized rubber, said process comprising: (i) providing a eutectic composition blend, said eutectic composition blend comprising a eutectic composition and an inert carrier, said inert carrier being a solid particulate material, said inert carrier being selected from the group consisting of calcium carbonate, wollastonite, silicon dioxide, and mixtures of two or more thereof; (ii) introducing a sulfur-based curing agent and said eutectic composition blend into a vulcanizable rubber, thereby forming a vulcanizable composition comprising a mixture of said sulfur-based curing agent and said eutectic composition blend; (iii) heating said vulcanizable composition, thereby causing vulcanization.

2. The process of claim 1, wherein said vulcanizable composition comprises less than 2 pbw of zinc oxide per 100 pbw of rubber.

3. The process of claim 1 or 2, wherein said vulcanizable composition further comprises a reinforcing filler, a resin, and an oil in addition to said inert carrier, said resin being present in an amount greater than 15 parts by weight per 100 parts by weight of rubber, said reinforcing filler being silica, said silica being present in an amount of at least 25 parts by weight per 100 parts by weight of rubber.

4. The process according to any one of claims 1 to 3, wherein said eutectic composition is defined by the formula Cat+X−zY, wherein Cat+ is a cation, X− is a counter anion, and z represents the number of Y molecules interacting with said counter anion.

5. The eutectic composition is formed by combining an ammonium compound with a metal halide, a metal halide hydrate, or a hydrogen bond donor, and said ammonium compound may be defined by formula II. 【Number 1】 wherein each R １ , R ２ , R ３ , and R ４ is individually hydrogen or a monovalent organic group, or alternatively, two of R １ , R ２ , R ３ , and R ４ are combined to form a divalent organic group, Φ － is a counteranion, and the hydrogen bond donor is selected from the group consisting of amines, amides, carboxylic acids, and alcohols. The process according to any one of claims 1 to 4.

6. The process according to any one of claims 1 to 5, wherein the median diameter of said inert carrier is less than 200 nm.

7. The process according to any one of claims 1 to 6, wherein said inert carrier is selected from the group consisting of calcium carbonate, wollastonite, and mixtures thereof.

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