Rubber vulcanization method using eutectic mixture

Abstract

This invention relates to a method for vulcanizing rubber using a eutectic mixture. The invention discloses a method for preparing vulcanized rubber, the method comprising: (i) providing a vulcanizable material composition comprising a sulfur-based curing agent, zinc oxide, and a eutectic solvent; and (ii) heating the vulcanizable composition to achieve vulcanization.

Description

[0001] This application is a divisional application of the application filed on October 31, 2018, with application number 201880071361.1 and invention title "Rubber Vulcanization Method Using Eutectic Mixture". Technical Field

[0002] Embodiments of the present invention relate to a method for sulfur curing a diene-based rubber composition in the presence of zinc oxide and a eutectic solvent. Background Technology

[0003] Zinc oxide, often combined with stearic acid, is commonly used in the vulcanization of rubber. Zinc compounds and / or zinc oxide are believed to act as activators for sulfur crosslinking. It is also believed that zinc oxide and stearic acid form zinc compounds in situ, and that their combination affects the rate and quality of the vulcanization process.

[0004] The zinc oxide commonly used in the sulfurization process is characterized by a BET surface area of ​​less than 10 m². 2 / g, the zinc oxide can be referred to as micro zinc oxide. Generally speaking, especially in the tire industry, rubber vulcanization requires at least about 2 parts by weight (pbw) zinc oxide / 100pbw rubber to achieve the desired curing. It has also been proposed that the BET surface area is greater than 10m². 2 / g of nano-zinc oxide has been used, and methods have been proposed that can provide improvements by ultimately requiring less loading of zinc oxide or other zinc substances. However, there are several difficulties in using nano-zinc oxide, including manufacturing problems and particle agglomeration.

[0005] The goal remains to reduce the amount of zinc, specifically zinc oxide, used in the manufacture of tire components. Summary of the Invention

[0006] One or more embodiments of the present invention provide a method for preparing vulcanized rubber, the method comprising providing a vulcanizable material composition comprising a sulfur-based curing agent, zinc oxide and a eutectic composition; and heating the vulcanizable composition to achieve vulcanization.

[0007] Another embodiment of the present invention provides a vulcanized rubber comprising a vulcanized rubber network, the vulcanized rubber network comprising a metal compound dispersed throughout the rubber network, the vulcanized rubber comprising less than 2 parts by weight of zinc oxide / 100 parts by weight of rubber.

[0008] Other embodiments of the present invention provide a vulcanized rubber prepared by a method comprising the step of preparing a vulcanized rubber, the method comprising providing a vulcanizable material composition comprising a sulfur-based curing agent, zinc oxide and a eutectic composition; and heating the vulcanizable composition to achieve vulcanization.

[0009] Other embodiments of the present invention provide a method for preparing a vulcanizable material composition, the method comprising mixing a vulcanizable rubber, a curing agent, and a eutectic composition. Detailed Implementation

[0010] Embodiments of the present invention are based, at least in part, on the discovery of a method for the vulcanization of a rubber composition, the method comprising curing the rubber in the presence of a metal compound (such as zinc) and a eutectic composition. It has been unexpectedly found that by including the eutectic composition in a vulcanizable composition, the total load of metal compounds necessary to achieve the desired curing can be significantly reduced without adversely affecting the curing rate and / or curing quality of the rubber. Furthermore, in some embodiments, the inclusion of the eutectic composition surprisingly leads to further improvements in one or more of the properties of the vulcanized rubber, such as reduced wear and reduced rolling resistance. Therefore, embodiments of the present invention provide cured tire components with a relatively low content of metals (such as zinc) and a technically useful level of curing.

[0011] Vulcanizable Composition

[0012] As described above, a eutectic composition is incorporated into a vulcanizable composition for the production of a sulfur-cured vulcanizable rubber. In addition to the eutectic composition, one or more embodiments of the vulcanizable composition further comprise a vulcanizable rubber, fillers, a sulfur-based curing agent, stearic acid, and a metal compound, such as zinc oxide or zinc oxide derivatives. Other optional components may also be included, such as, but not limited to, processing oils and / or extender oils, resins, waxes, curing accelerators, scorch inhibitors, degradation inhibitors, antioxidants, and other rubber compounding additives known in the art.

[0013] Eutectic mixture

[0014] In one or more embodiments, eutectic compositions include those formed by mixing two or more compounds, the compositions providing a combination with a melting point lower than that of the respective compounds being mixed. 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 mixed compounds may be referred to, respectively, as a eutectic component, eutectic element, eutectic member, or compound used to form the eutectic composition (e.g., first compound and second compound). Depending on the relative amounts of the respective eutectic components and the temperature at which the observation is made, the eutectic composition may be in liquid form, which may be referred to as a eutectic liquid or 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 composition may be referred to as a deep eutectic solvent, which may be called a DES.

[0015] It is not desired to be bound by any particular theory that eutectic components mix, otherwise react, or interact to form complexes. Therefore, any reference to eutectic mixtures or eutectic combinations, eutectic pairs, or eutectic complexes will include combinations and reaction products or complexes between the mixed components that produce a lower melting point than the respective components. For example, in one or more embodiments, a usable eutectic composition may be defined by Formula I:

[0016] Cat + X - zY

[0017] Cat + X is a cation. - To counteract anions (e.g., Lewis bases), and z refers to the number of Y molecules that interact with said counter anion (e.g., Lewis acids or Brønsted acids). For example, Cat + It may include ammonium, phosphonium, or sulfonium cations. X - It may include, for example, halide ions. Y may include, for example, hydrogen bond donors, metal halides, or metal halide hydrates. In one or more embodiments, z is the amount of solvent that achieves deep eutectic melting, or in other embodiments, the amount of a complex that otherwise obtains a melting point lower than the corresponding eutectic component.

[0018] In one or more embodiments, the available eutectic composition comprises a combination of an acid and a base, wherein the acid and base may comprise a Lewis acid and a Lewis base or a Brønsted acid and a Brønsted base. In one or more embodiments, the available eutectic composition comprises a combination of a quaternary ammonium salt and a metal halide (referred to as a Type I eutectic composition), a combination of a quaternary ammonium salt and a metal halide hydrate (referred to as a Type II eutectic composition), a combination of a quaternary ammonium salt and a hydrogen bond donor (referred to as a Type III eutectic composition), or a combination of a metal halide hydrate and a hydrogen bond donor (referred to as a Type IV eutectic composition). Similar combinations of sulfonium or phosphonium, instead of ammonium compounds, may also be used and are readily conceived by those skilled in the art.

[0019] Quaternary ammonium salts

[0020] In one or more embodiments, the quaternary ammonium salt is a solid at 20°C. In these or other embodiments, the metal halide and hydrogen bond donor are solids at 20°C.

[0021] In one or more embodiments, the available quaternary ammonium salt (also referred to as an ammonium compound) can be defined by Formula II:

[0022] (R1)(R2)(R3)(R4)—N + —Φ –

[0023] 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 combined to form a divalent organic group, and Φ- is a counter anion. In one or more embodiments, at least one of R1, R2, R3, and R4, in other embodiments at least two, and in still other embodiments at least three are not hydrogen.

[0024] In one or more embodiments, the counter anion (e.g., Φ-) is selected from halide ions (X-), nitrate ions (NO3-), tetrafluoroborate ions (BF4-), perchlorate ions (ClO4-), and trifluoromethanesulfonate ions (SO3CF3-). - ), trifluoroacetate (COOCF3) - In one or more embodiments, Φ- is a halide ion, and in some embodiments it is a chloride ion.

[0025] In one or more embodiments, the monovalent organic group includes a hydrocarbon group, and the divalent organic group includes an alkylene group. In one or more embodiments, the monovalent and divalent organic groups include heteroatoms, such as, but not limited to, oxygen and nitrogen, and / or halogen atoms. Thus, the monovalent organic group may include alkoxy groups, silanoxy groups, ether groups, and ester groups, as well as carbonyl or acetyl substituents. In one or more embodiments, the hydrocarbon group and the alkylene group include one (or a suitable minimum number) to about 18 carbon atoms, in other embodiments one to about 12 carbon atoms, and in other embodiments one to about 6 carbon atoms. The hydrocarbon group and the alkylene group may be branched, cyclic, or linear. Exemplary types of hydrocarbon groups include alkyl, cycloalkyl, aryl, and alkylaryl groups. Exemplary types of alkylene groups include alkylene, cycloalkylene, aryl, and alkylarylene groups. In a specific embodiment, the hydrocarbon group is selected from methyl, ethyl, octadecyl, phenyl, and benzyl groups. In some embodiments, the hydrocarbon group is a methyl group, and the hydrocarbon group is an ethylene or propylene group.

[0026] Available types of ammonium compounds include secondary ammonium compounds, tertiary ammonium compounds, and quaternary ammonium compounds. In these or other embodiments, the ammonium compound includes ammonium halides, such as, but not limited to, ammonium chloride. In a particular embodiment, the ammonium compound is a quaternary ammonium chloride. In some 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.

[0027] In one or more embodiments, the ammonium compound comprises an alkoxy group and may be defined by Formula III:

[0028] (R1)(R2)(R3)—N +—(R4—OH)Φ -

[0029] Each of R1, R2, and R3 is independently hydrogen or a monovalent organic group, or alternatively, two of R1, R2, and R3 are combined to form a divalent organic group, R4 is a divalent organic group, and Φ – To counteract anions. In one or more embodiments, at least one of R1, R2, and R3, in other embodiments at least two, and in other embodiments at least three are not hydrogen.

[0030] Examples of ammonium compounds defined by Formula III include, but are not limited to, N-ethyl-2-hydroxy-N,N-dimethylethylammonium chloride, 2-hydroxy-N,N,N-trimethylethylammonium chloride (also known as choline chloride), and N-benzyl-2-hydroxy-N,N-dimethylethylammonium chloride.

[0031] In one or more embodiments, the ammonium compound includes a halogen-containing substituent and may be defined by Formula IV:

[0032] Φ – —(R1)(R2)(R3)—N + —R4X

[0033] Each of R1, R2, and R3 is independently a hydrogen or monovalent organic group, or alternatively, two of R1, R2, and R3 combine to form a divalent organic group, R4 is a divalent organic group, X is a halogen atom, and Φ – To counteract anions. In one or more embodiments, at least one of R1, R2, and R3, in other embodiments at least two, and in other embodiments at least three are not hydrogen. In one or more embodiments, X is chlorine.

[0034] Examples of ammonium compounds defined by Formula III include, but are not limited to, 2-chloro-N,N,N-trimethylethylammonium (also known as chlorocholine chloride) and 2-(chlorocarbonyloxy)-N,N,N-trimethylethylammonium chloride.

[0035] Hydrogen bond donor compounds

[0036] In one or more embodiments, the hydrogen bond donor compound (which may also be referred to as an HBD compound) includes, but is not limited to, amines, amides, carboxylic acids, and alcohols. In one or more embodiments, the hydrogen bond donor compound comprises a hydrocarbon chain component. The hydrocarbon chain component may include a carbon chain length having at least 2 carbon atoms, at least 3 carbon atoms in other embodiments, and at least 5 carbon atoms in other embodiments. In these or other embodiments, the hydrocarbon chain component has a carbon chain length of less than 30 carbon atoms, less than 20 carbon atoms in other embodiments, and less than 10 carbon atoms in other embodiments.

[0037] In one or more embodiments, the available amines include those compounds defined by the following formula:

[0038] R1—(CH2) x —R2

[0039] Wherein R1 and R2 are -NH2, -NHR3, or -NR3R4, and x is an integer of at least 2. In one or more embodiments, x is 2 to about 10, in other embodiments it is about 2 to about 8, and in still other embodiments it is about 2 to about 6.

[0040] Specific examples of amines that may be used include, but are not limited to, aliphatic amines, ethylenediamine, diethylenetriamine, aminoethylpiperazine, triethylenetetramine, tri(2-aminoethyl)amine, N,N'-bis-(2-aminoethyl)piperazine, piperazine ethyl ethylenediamine and tetraethylenepentamine, propylenediamine, aniline, substituted aniline, and combinations thereof.

[0041] In one or more embodiments, the available amines include those compounds defined by the following formula:

[0042] R—CO—NH2

[0043] Where R is H, NH2, CH3 or CF3.

[0044] Specific examples of available amides include, but are not limited to, urea, 1-methylurea, 1,1-dimethylurea, 1,3-dimethylurea, thiourea, urea, benzamide, acetamide, and combinations thereof.

[0045] In one or more embodiments, the available carboxylic acids include monofunctional, difunctional, and trifunctional organic acids. These organic acids may include alkyl acids, arylic acids, and mixtures of alkyl-arylic acids.

[0046] Specific examples of available 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, mesonic acid tricarboxylic acid, and combinations thereof.

[0047] The types of alcohols include, but are not limited to, monohydric alcohols, dihydric alcohols, and trihydric alcohols. Specific examples of monohydric alcohols include fatty alcohols, phenols, substituted phenols, and mixtures thereof. Specific examples of dihydric alcohols include ethylene glycol, propylene glycol, resorcinol, substituted resorcinols, and mixtures thereof. Specific examples of trihydric alcohols include, but are not limited to, glycerol, glycerol, and mixtures thereof.

[0048] metal halides

[0049] 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. Those skilled in the art can readily conceive of corresponding metal halide hydrates.

[0050] Specific examples of available 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, ferric chloride, ferric bromide, ferric iodide, and combinations thereof. Those skilled in the art can readily conceive of corresponding metal halide hydrates. For example, aluminum chloride hexahydrate and copper chloride dihydrate correspond to the above-mentioned halides.

[0051] Formation of eutectic complex

[0052] A skilled craftsman can select appropriate eutectic members by using suitable molar ratios to provide a desired eutectic composition. The skilled craftsman understands that the molar ratio of the first compound (e.g., a Lewis base) to the second compound (e.g., a Lewis acid) in the pair will vary based on the selected compounds. As will also be understood by the skilled craftsman, melting point suppression of the eutectic solvent includes the eutectic point, which is the molar ratio of the first compound to the second compound that produces minimum melting point suppression (i.e., deep eutectic solvent). However, the molar ratio of the first compound to the second compound can be varied to produce melting point suppression of the eutectic solvent relative to the individual melting points of the first and second compounds, which is not the minimum melting point. Therefore, operation of one or more embodiments of the invention involves forming the eutectic solvent at a molar ratio other than the eutectic point.

[0053] In one or more embodiments, the eutectic pair of compounds, and the molar ratio of the first compound to the second compound in the pair, are selected to produce a mixture with a melting point below 130°C, below 110°C in other embodiments, below 100°C in other embodiments, below 80°C in other embodiments, below 60°C in other embodiments, below 40°C in other embodiments, and below 30°C in other embodiments. In these or other embodiments, the eutectic pair of compounds, and the molar ratio of the compounds, are selected to produce a mixture with a melting point above 0°C, above 10°C in other embodiments, above 20°C in other embodiments, above 30°C in other embodiments, and above 40°C in other embodiments.

[0054] In one or more embodiments, a eutectic pair of compounds and the molar ratio of the first to the second compound of the pair are selected to produce a eutectic solvent having the ability or capacity to dissolve a desired metal compound, which may be referred to as solubility or dissolving capacity. As those skilled in the art will understand, when preparing a saturated solution, 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. In one or more embodiments, the eutectic solvent of the present invention is selected to achieve a zinc oxide solubility of greater than 100 ppm over 24 hours at 50°C and atmospheric pressure, 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, and greater than 1600 ppm in other embodiments, wherein ppm is measured based on the weight of the solute against the weight of the solvent.

[0055] In one or more embodiments, a eutectic solvent (i.e., a liquid composition at a desired temperature) is formed by mixing a first compound with a second compound in an appropriate molar ratio to provide a solvent composition. The mixture can be mechanically stirred using various techniques, including but not limited to solid-state mixing or blending techniques. Generally, the mixture is mixed or otherwise stirred until a visually homogeneous liquid is formed. Alternatively, the mixture can be formed at elevated temperatures. For example, a eutectic solvent can be formed by heating the mixture to temperatures greater than 50°C, greater than 70°C in other embodiments, and greater than 90°C in other embodiments. Mixing can continue during the 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 eutectic solvent can be carried out at a controlled rate, such as less than 1°C / min.

[0056] In one or more embodiments, the available eutectic compositions are commercially available. For example, deep eutectic solvents are commercially available from Scionix under the trade name Ionic Liquids. Available eutectic compositions are also generally known, as described in U.S. Patent Publications 2004 / 0097755A1 and 2011 / 0207633A1, which are incorporated herein by reference.

[0057] Vulcanizable rubber

[0058] In one or more embodiments, vulcanizable rubber (also referred to as rubber or vulcanizable elastomer) may include those polymers that can be vulcanized to form compositions having rubber or elastomer properties. These elastomers may include natural rubber and synthetic rubber. Synthetic rubber is typically derived from the polymerization of conjugated diene monomers, copolymerization of conjugated diene monomers with other monomers such as vinyl-substituted aromatic monomers, or copolymerization of ethylene with one or more α-olefins and optionally one or more diene monomers.

[0059] Exemplary elastomers include natural rubber, synthetic polyisoprene, polybutadiene, polyisobutylene-isoprene copolymer, chloroprene rubber, polyethylene-propylene copolymer, polystyrene-butadiene copolymer, polystyrene-isoprene copolymer, polystyrene-isoprene-butadiene copolymer, polyisoprene-butadiene copolymer, polyethylene-propylene-diene copolymer, polysulfide rubber, acrylic rubber, polyurethane rubber, silicone rubber, epichlorohydrin rubber, and mixtures thereof. These elastomers can have a wide variety of macromolecular structures, including linear, branched, and star-shaped structures. These elastomers may also contain one or more functional units, which typically include heteroatoms.

[0060] filler

[0061] As described above, the vulcanizable compositions of the present invention may contain one or more fillers. These filler materials may include reinforced and unreinforced fillers. Exemplary fillers include carbon black, silica, and various inorganic fillers.

[0062] Available carbon blacks include furnace black, channel black, and lamp black. More specific examples of carbon blacks include ultra-abrasion furnace black, medium-ultra-abrasion furnace black, high-abrasion furnace black, fast extrusion furnace black, fine furnace black, semi-reinforced furnace black, medium-process channel black, difficult-to-process channel black, conductive channel black, and acetylene black.

[0063] In a particular embodiment, the surface area (EMSA) of the carbon black may be at least 20 m². 2 / g, and in other embodiments at least 35m 2 / g; Surface area values ​​can be determined using the cetyltrimethylammonium bromide (CTAB) technique according to ASTM D-1765. Carbon black can be in granular or non-granular flocculent form. The preferred form of carbon black may depend on the type of mixing equipment used to blend the rubber compounds.

[0064] Examples of suitable silica fillers include precipitated amorphous silica, wet silica (hydrated silica), dry silica (anhydrous silica), pyrolytic silica, calcium silicate, aluminum silicate, magnesium silicate, etc.

[0065] In one or more embodiments, silica can be characterized by its surface area, which provides a measure of its reinforcing properties. The Brunauer, Emmet, and Teller (“BET”) method (described in the Journal of the American Chemical Society, Vol. 60, p. 309 onwards) is a recognized method for determining surface area. The BET surface area of ​​silica is typically less than 450 m². 2 / g. The useful range of surface area includes about 32 to about 400m². 2 / g, approximately 100 to approximately 250mm 2 / g and about 150 to about 220m 2 / g.

[0066] When one or more silicas are used, the pH of the silica is typically from about 5 to about 7 or slightly above 7, or from about 5.5 to about 6.8 in other embodiments.

[0067] In one or more embodiments, when silica is used as a filler (alone or in combination with other fillers), coupling agents and / or masking agents may be added to the rubber composition during mixing to enhance the interaction between silica and the elastomer. Available coupling agents and masking 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 incorporated herein by reference. Examples of sulfur-containing silica coupling agents include bis(trialkoxysilyl)polysulfides or mercapto-organoalkoxysilanes. Types of bis(trialkoxysilyl)polysulfides include bis(trialkoxysilyl)disulfides and bis(trialkoxysilyl)tetrasulfides.

[0068] Other useful filler materials include a variety of inorganic 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 (hydrated magnesium silicate), and clay (hydrated aluminum silicate).

[0069] resin

[0070] As described above, the vulcanizable compositions of the present invention may comprise one or more resins. These resins may include phenolic resins and hydrocarbon resins, such as alicyclic resins, aliphatic resins, aromatic resins, terpene resins, and combinations thereof. Available resins are commercially available under various trade names from numerous companies, including, 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, SI Group Inc., and Zeon.

[0071] In one or more embodiments, the available hydrocarbon resin is characterized by a glass transition temperature (Tg) of about 30°C to about 160°C, in other embodiments about 35°C to about 60°C, and in other embodiments about 70°C to about 110°C. In one or more embodiments, the available hydrocarbon resin is also characterized by a softening point higher than its Tg. In some embodiments, the available hydrocarbon resin has a softening point of about 70°C to about 160°C, in other embodiments about 75°C to about 120°C, and in other embodiments about 120°C to about 160°C.

[0072] In some embodiments, one or more alicyclic resins are used in combination with one or more alicyclic resins, aromatic resins, and terpene resins. In one or more embodiments, one or more alicyclic resins are used as the major weight component (e.g., greater than 50% by weight) relative to the total resin load. For example, the resin used contains at least 55% by weight, at least 80% by weight in other embodiments, and at least 99% by weight of one or more alicyclic resins in other embodiments.

[0073] In one or more embodiments, alicyclic resins include both alicyclic homopolymer resins and alicyclic copolymer resins, comprising those derived from alicyclic monomers, optionally combined with one or more other (non-alicyclic) monomers, wherein the majority of all monomers by weight are alicyclic. Suitable non-limiting examples of available alicyclic resins include cyclopentadiene (“CPD”) homopolymer or copolymer resins, 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), C… PD / aromatic-aliphatic copolymer resins (e.g., CPD / C5 and C9 fractional copolymer resins), DCPD / aromatic-aliphatic copolymer resins (e.g., DCPD / C5 and C9 fractional 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 some embodiments, the alicyclic resin may include a hydrogenated form of one of the above-mentioned alicyclic resins (i.e., hydrogenated alicyclic resins). In other embodiments, the alicyclic resin does not include any hydrogenated alicyclic resin; in other words, the alicyclic resin is not hydrogenated.

[0074] In some embodiments, one or more aromatic resins are used in combination with one or more aliphatic resins, alicyclic resins, and terpene resins. In one or more embodiments, one or more aromatic resins are used as the major weight component (e.g., greater than 50% by weight) relative to the total resin load. For example, the resin used contains at least 55% by weight, at least 80% by weight in other embodiments, and at least 99% by weight of one or more aromatic resins in other embodiments.

[0075] In one or more embodiments, aromatic resins include both aromatic homopolymer resins and aromatic copolymer resins, including those derived from combinations of one or more aromatic monomers with one or more other (non-aromatic) monomers, wherein the largest quantity of any type of monomer is aromatic. Non-limiting examples of available aromatic resins include coumarone-indene resins and alkyl-phenol resins, as well as vinyl aromatic homopolymer or copolymer resins, such as those derived from one or more of the following monomers: α-methylstyrene, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-(tert-butyl)styrene, methoxystyrene, chlorostyrene, hydroxystyrene, vinyltrimethylbenzene, divinylbenzene, vinylnaphthalene, or any vinyl aromatic monomer 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 resins), vinyl aromatic / C5 fraction resins (e.g., C5 fraction / styrene copolymer resins), and vinyl aromatic / aliphatic copolymer resins (e.g., CPD / styrene copolymer resins and DCPD / styrene copolymer resins). Non-limiting examples of alkyl-phenol resins include alkylphenol-acetylene resins, such as p-tert-butylphenol-acetylene resins, and alkylphenol-formaldehyde resins (such as those with low degrees of polymerization). In some embodiments, the aromatic resin may include a hydrogenated form of one of the above-described aromatic resins (i.e., a hydrogenated aromatic resin). In other embodiments, the aromatic resin does not include any hydrogenated aromatic resin; in other words, the aromatic resin is not hydrogenated.

[0076] In some embodiments, one or more aliphatic resins are used in combination with one or more alicyclic resins, aromatic resins, and terpene resins. In one or more embodiments, one or more aliphatic resins are used as the major weight component (e.g., greater than 50% by weight) relative to the total resin load. For example, the resin used contains at least 55% by weight, at least 80% by weight in other embodiments, and at least 99% by weight of one or more aliphatic resins in other embodiments.

[0077] In one or more embodiments, aliphatic resins include both aliphatic homopolymer resins and aliphatic copolymer resins, which include those resins derived from combinations of one or more aliphatic monomers with one or more other (non-aliphatic) monomers, wherein the largest amount of any type of monomer is aliphatic. Non-limiting examples of available aliphatic resins include C5 fraction homopolymer or copolymer resins, C5 fraction / C9 fraction copolymer resins, C5 fraction / vinyl aromatic copolymer resins (e.g., C5 fraction / styrene copolymer resins), C5 fraction / alicyclic copolymer resins, C5 fraction / C9 fraction / alicyclic copolymer resins, and combinations thereof. Non-limiting examples of alicyclic monomers include, but are not limited to, cyclopentadiene (“CPD”) and dicyclopentadiene (“DCPD”). In some embodiments, the aliphatic resin may include a hydrogenated form of one of the above-described aliphatic resins (i.e., a hydrogenated aliphatic resin). In other embodiments, the aliphatic resin does not include any hydrogenated aliphatic resin; in other words, in such embodiments, the aliphatic resin is not hydrogenated.

[0078] In one or more embodiments, terpene resins include both terpene homopolymer resins and terpene copolymer resins, comprising those resins derived from combinations of one or more terpene monomers with one or more other (non-terpene) monomers, wherein the largest quantity of any type of monomer is a terpene. Non-limiting examples of available terpene resins include α-pinene resins, β-pinene resins, limonene resins (e.g., L-limonene, D-limonene, dipentene as a racemic mixture of L-isomers and D-isomers), β-phellandrene, δ-3-carene, δ-2-carene, pinene-limonene copolymer resins, terpene-phenol resins, aromatically modified terpene resins, and combinations thereof. In some embodiments, the terpene resin may comprise a hydrogenated form of one of the above-described terpene resins (i.e., a hydrogenated terpene resin). In other embodiments, the terpene resin does not include any hydrogenated terpene resin; in other words, in such embodiments, the terpene resin is not hydrogenated.

[0079] curing agent

[0080] Rubber curing agents (also known as vulcanizing agents) include sulfur-based curing systems. Curing agents are described in the following literature: Kirk-Othmer, Encyclopedia of Chemical Technology, Vol. 20, pp. 365-468 (3rd edition, 1982). rdThe references cited herein are: Ed. 1982, specifically in “Vulcanization Agents and Auxiliary Materials,” pp. 390–402, and A.Y. Coran, *Vulcanization, Encyclopedia of Polymer Science and Engineering*, 2nd Ed. 1989, which are incorporated herein by reference. In one or more embodiments, the curing agent is sulfur. Examples of suitable sulfur-based vulcanizing agents include soluble sulfur of “rubber products”; sulfur-containing vulcanizing agents such as disulfide, polymeric polysulfides, or sulfur olefin adducts; and insoluble polymeric sulfur. Vulcanizing agents may be used alone or in combination. Those skilled in the art will be able to readily select the amount of vulcanizing agent to achieve the desired level of curing.

[0081] In one or more embodiments, a curing agent and a curing accelerator are used in combination. In one or more embodiments, the 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 such as 2-mercaptobenzothiazole, dibenzothiazole disulfide, N-cyclohexyl-2-benzothiazole sulfinamide (CBS), etc.; and guanidine vulcanization accelerators such as diphenylguanidine (DPG), etc. Those skilled in the art will be able to easily select the amount of curing accelerator to achieve the desired level of curing.

[0082] Other ingredients

[0083] Other components commonly used in rubber compounding may also be added to the rubber composition. These components include accelerators, accelerator activators, oils, additional plasticizers, waxes, scorch inhibitors, processing aids, zinc oxide, tackifying resins, reinforcing resins, fatty acids (such as stearic acid), plasticizers, and anti-degradation agents (such as antioxidants and anti-ozone agents). In certain embodiments, the oils used include those commonly used as incrementing oils. Available oils or incrementing agents include, but are not limited to, aromatic oils, paraffinic oils, naphthenic oils, vegetable oils other than castor oil, low-PCA oils (including MES, TDAE, and SRAE), and heavy naphthenic oils. Suitable low-PCA oils also include oils from a variety of plant sources, such as oils harvested from vegetables, nuts, and seeds. Non-limiting examples include, but are not limited to, soybean oil or yellow soybean oil, sunflower oil, safflower oil, corn oil, flaxseed oil, cottonseed oil, rapeseed oil, hemp oil, cashew oil, sesame oil, camellia oil, jojoba oil, macadamia oil, coconut oil, and palm oil.

[0084] Metal activators and organic acids

[0085] As described above, the vulcanizable compositions of the present invention comprise a metal compound. In one or more embodiments, the metal compound is an activator (i.e., one that facilitates the vulcanization or curing of the rubber). In other embodiments, the metal activator is a metal oxide. In a particular embodiment, the metal activator is zinc oxide. In other embodiments, the metal activator is a zinc substance formed in situ by a 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.

[0086] In one or more embodiments, the zinc oxide is unfunctionalized zinc oxide, characterized in that its BET surface area is less than 10 m². 2 / g, less than 9m in other implementations 2 / g, and less than 8m in other implementations. 2 / g. In other embodiments, nano-zinc oxide is used, characterized by a BET surface area greater than 10m². 2 Those zinc oxide particles per g.

[0087] In one or more embodiments, the organic acid is a carboxylic acid. In a particular embodiment, the carboxylic acid is a fatty acid, including both saturated and unsaturated fatty acids. In a particular embodiment, a saturated fatty acid, such as stearic acid, is used. Other available acids include, but are not limited to, palmitic acid, arachidic acid, oleic acid, linoleic acid, and arachidonic acid.

[0088] Component amount

[0089] rubber

[0090] In one or more embodiments, the vulcanizable composition comprises at least 20% by weight of a rubber component based on the total weight of the composition, at least 30% by weight in other embodiments, and at least 40% by weight in other embodiments. In these or other embodiments, the vulcanizable composition comprises up to 90% by weight of a rubber component based on the total weight of the composition, at most 70% by weight in other embodiments, and at most 60% by weight in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 20% to about 90% by weight of a rubber component based on the total weight of the composition, at most 30% to about 70% by weight in other embodiments, and at most 40% to about 60% by weight in other embodiments.

[0091] Eutectic composition

[0092] In one or more embodiments, the vulcanizable composition comprises more than 0.005 parts by weight (pbw) of eutectic composition per 100 parts by weight of rubber (phr), more than 0.01 pbw of eutectic composition in other embodiments, and more than 0.02 pbw of eutectic composition in other embodiments. In these or other embodiments, the vulcanizable composition comprises less than 3 pbw of eutectic composition per 100 parts by weight of rubber (phr), less than 1 pbw of eutectic composition in other embodiments, and less than 0.1 pbw of eutectic composition in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 0.005 pbw to about 3 pbw of eutectic composition per 100 parts by weight of rubber (phr), about 0.01 pbw to about 1 pbw of eutectic composition in other embodiments, and about 0.02 pbw to about 0.1 pbw of eutectic composition in other embodiments.

[0093] In one or more embodiments, the amount of eutectic solvent may be described with reference to the loading of a metal activator (such as zinc oxide). In one or more embodiments, the vulcanizable composition contains more than 2% by weight of eutectic solvent based on the total weight of the eutectic solvent and metal activator (e.g., zinc oxide) present in the vulcanizable composition, more than 3% by weight in other embodiments, and more than 5% by weight in other embodiments. In these or other embodiments, the vulcanizable composition contains less than 15% by weight of eutectic solvent based on the total weight of the eutectic solvent and metal activator (e.g., zinc oxide) present in the vulcanizable composition, less than 12% by weight in other embodiments, and less than 10% by weight in other embodiments. In one or more embodiments, the vulcanizable composition contains about 2% to about 15% by weight of eutectic solvent based on the total weight of the eutectic solvent and metal activator (e.g., zinc oxide) present in the vulcanizable composition, about 3% to about 12% by weight in other embodiments, and about 5% to about 10% by weight in other embodiments.

[0094] Metal compounds

[0095] In one or more embodiments, the vulcanizable composition comprises more than 0.05 parts by weight (pbw) of a metal activator (e.g., zinc oxide) per 100 parts by weight of rubber (phr), more than 0.1 pbw of a metal activator (e.g., zinc oxide) in other embodiments, and more than 0.15 pbw of a metal activator (e.g., zinc oxide) in other embodiments. In these or other embodiments, the vulcanizable composition comprises less than 2 pbw of a metal activator (e.g., zinc oxide) per 100 parts by weight of rubber (phr), less than 1 pbw of a metal activator (e.g., zinc oxide) in other embodiments, and less than 0.75 pbw of a metal activator (e.g., zinc oxide) in other embodiments. In one or more embodiments, the vulcanizable composition contains about 0.05 pbw to about 2 pbw of a metal activator (e.g., zinc oxide) per 100 parts by weight of rubber (phr), in other embodiments it contains about 0.1 pbw to about 1 pbw of a metal activator (e.g., zinc oxide), and in other embodiments it contains about 0.15 pbw to about 0.75 pbw of a metal activator (e.g., zinc oxide).

[0096] organic acids

[0097] In one or more embodiments, the vulcanizable composition comprises more than 0.5 parts by weight (pbw) of an organic acid (e.g., stearic acid) per 100 parts by weight of rubber (phr), more than 0.7 pbw of an organic acid (e.g., stearic acid) in other embodiments, and more than 1.0 pbw of an organic acid (e.g., stearic acid) in other embodiments. In these or other embodiments, the vulcanizable composition comprises less than 5 pbw of an organic acid (e.g., stearic acid) per 100 parts by weight of rubber (phr), less than 3 pbw of an organic acid (e.g., stearic acid) in other embodiments, and less than 2 pbw of an organic acid (e.g., stearic acid) in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 0.5 pbw to about 5 pbw of an organic acid (e.g., stearic acid) per 100 parts by weight of rubber (phr), in other embodiments it comprises about 0.7 pbw to about 3 pbw of an organic acid (e.g., stearic acid), and in other embodiments it comprises about 1.0 pbw to about 2 pbw of an organic acid (e.g., stearic acid).

[0098] filler

[0099] In one or more embodiments, the vulcanizable composition comprises at least 0 parts by weight (pbw) of filler per 100 parts by weight of rubber (phr), at least 10 pbw of filler in other embodiments, and at least 20 pbw of filler in other embodiments. In these or other embodiments, the vulcanizable composition comprises up to 200 pbw of filler per 100 parts by weight of rubber (phr), at most 100 pbw of filler in other embodiments, and at most 70 pbw of filler in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 0 pbw to about 200 pbw of filler per 100 parts by weight of rubber (phr), at most 10 pbw to about 100 pbw of filler in other embodiments, and at most 20 pbw to about 70 pbw of filler in other embodiments.

[0100] carbon black

[0101] In one or more embodiments, the vulcanizable composition comprises at least 0 parts by weight (pbw) of carbon black per 100 parts by weight of rubber (phr), at least 10 pbw of carbon black in other embodiments, and at least 20 pbw of carbon black in other embodiments. In these or other embodiments, the vulcanizable composition comprises up to 200 pbw of carbon black per 100 parts by weight of rubber (phr), at most 100 pbw of carbon black in other embodiments, and at most 70 pbw of carbon black in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 0 pbw to about 200 pbw of carbon black per 100 parts by weight of rubber (phr), at most 10 pbw to about 100 pbw of carbon black in other embodiments, and at most 20 pbw to about 70 pbw of carbon black in other embodiments.

[0102] silicon dioxide

[0103] In one or more embodiments, the vulcanizable composition comprises at least 5 parts by weight (pbw) of silica per 100 parts by weight of rubber (phr), at least 25 pbw of silica in other embodiments, at least 50 pbw of silica in other embodiments, and at least 70 pbw of silica in other embodiments. In these or other embodiments, the vulcanizable composition comprises up to 200 pbw of silica per 100 parts by weight of rubber (phr), at most 130 pbw of silica in other embodiments, and at most 80 pbw of silica in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 5 pbw to about 200 pbw of silica per 100 parts by weight of rubber (phr), at most 25 pbw to about 130 pbw of silica in other embodiments, and at most 50 pbw to about 80 pbw of silica in other embodiments.

[0104] Filler ratio

[0105] In one or more embodiments, the vulcanizable composition may be characterized by a ratio of the amount of the first filler to the amount of the second filler. In one or more embodiments, the ratio of carbon black to silica is about 1:1, in other embodiments about 10:1, in other embodiments about 14:1, and in other embodiments about 20:1. In one or more embodiments, the ratio of carbon black to silica is about 1:5, in other embodiments about 1:10, in other embodiments about 1:14, and in other embodiments about 1:20.

[0106] Silica coupling agent

[0107] In one or more embodiments, the vulcanizable composition comprises at least 1 part by weight (pbw) of silica coupling agent per 100 parts by weight of silica, at least 2 pbw of silica coupling agent in other embodiments, and at least 5 pbw of silica coupling agent in other embodiments. In these or other embodiments, the vulcanizable composition comprises up to 20 pbw of silica coupling agent per 100 parts by weight of silica, at most 15 pbw of silica coupling agent in other embodiments, and at most 10 pbw of silica coupling agent in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 1 pbw to about 20 pbw of silica coupling agent per 100 parts by weight of silica, about 2 pbw to about 15 pbw of silica coupling agent in other embodiments, and about 5 pbw to about 10 pbw of silica coupling agent in other embodiments.

[0108] resin

[0109] In one or more embodiments, the vulcanizable composition comprises more than 1 part by weight (pbw) of resin (e.g., a hydrocarbon resin) per 100 parts by weight of rubber (phr), more than 15 pbw of resin (e.g., a hydrocarbon resin) in other embodiments, more than 25 pbw of resin (e.g., a hydrocarbon resin) in other embodiments, and more than 35 pbw of resin (e.g., a hydrocarbon resin) in other embodiments. In these or other embodiments, the vulcanizable composition comprises less than 150 pbw of resin (e.g., a hydrocarbon resin) per 100 parts by weight of rubber (phr), less than 120 pbw of resin (e.g., a hydrocarbon resin) in other embodiments, and less than 90 pbw of resin (e.g., a hydrocarbon resin) in other embodiments. In one or more embodiments, the vulcanizable composition comprises about 1 pbw to about 150 pbw of resin (e.g., hydrocarbon resin) per 100 parts by weight of rubber (phr), in other embodiments it comprises about 15 pbw to about 120 pbw of resin (e.g., hydrocarbon resin), and in other embodiments it comprises about 25 pbw to about 90 pbw of resin (e.g., hydrocarbon resin).

[0110] Method Overview

[0111] In one or more embodiments, a vulcanizable composition is prepared by mixing a vulcanizable rubber with a eutectic solvent to form a masterbatch, followed by adding a curing agent to the masterbatch. The preparation of the masterbatch may be carried out using one or more sub-mixing steps, wherein, for example, one or more components may be added sequentially to the composition after an initial mixture is prepared by mixing two or more ingredients. Additionally, using conventional techniques, additional components may be added to the preparation of the vulcanizable composition, such as, but 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, and anti-degradation agents such as antioxidants or anti-ozone agents.

[0112] In one or more embodiments, the eutectic composition is prepared prior to its introduction into the vulcanizable rubber. In other words, a first component of the mixture is premixed with a second component of the mixture before the mixture is introduced into the vulcanizable composition. In one or more embodiments, the combined components of the mixture are mixed until a homogeneous liquid composition is observed.

[0113] In one or more embodiments, the eutectic composition is premixed with one or more components of the rubber formulation before being introduced into the vulcanizable composition. In other words, in one or more embodiments, a component of the vulcanizable composition (e.g., a metal compound, such as zinc oxide) is mixed with the eutectic composition to form a premix or masterbatch before the premix is ​​introduced into a mixer in which the rubber is mixed. For example, zinc oxide may be dissolved in a eutectic solvent before being introduced into the rubber within the mixer. In other embodiments, the eutectic composition is a minor component of the premix, and thus the component premixed with the eutectic composition acts as a carrier for the eutectic composition. For example, the eutectic composition may be mixed with a larger volume of zinc oxide, and the zinc oxide will act as a carrier for delivering the combination of zinc oxide and the eutectic composition in solid form to the rubber within the mixer. In other embodiments, one member of the eutectic pair acts as a solid carrier for the eutectic composition, and thus the combination of the first and second components of the eutectic composition forms a premix that can be added to the rubber within the mixer in solid form. Those skilled in the art will understand that mixtures of this nature can be formed by mixing an excess of a first or second eutectic member relative to the other eutectic members in order to maintain the solid composition at a desired temperature.

[0114] In one or more embodiments, a eutectic solvent is introduced into the vulcanizable rubber as an initial component in the formation of the rubber masterbatch. Therefore, the eutectic solvent and rubber are mixed under high shear and high temperature. In one or more embodiments, the eutectic solvent and rubber are mixed at a minimum temperature exceeding 110°C, in other embodiments at a minimum temperature exceeding 130°C, and in still other embodiments at a minimum temperature exceeding 150°C. In one or more embodiments, the high shear and high temperature mixing is carried out at a temperature from about 110°C to about 170°C.

[0115] In other embodiments, the eutectic solvent and the sulfur-based curing agent are introduced sequentially or simultaneously into the vulcanizable rubber. Thus, the eutectic solvent and the vulcanizable rubber are mixed at a maximum temperature below 110°C, in other embodiments at a maximum temperature below 105°C, and in still other embodiments at a maximum temperature below 100°C. In one or more embodiments, mixing with the curing agent is carried out at a temperature of about 70°C to about 110°C.

[0116] Similar to eutectic solvents, zinc oxide and stearic acid can be added as initial components to rubber masterbatches, thus undergoing high-temperature, high-shear mixing. Alternatively, zinc oxide and stearic acid can be added together with a sulfur-based curing agent, resulting in only low-temperature mixing.

[0117] In one or more embodiments, zinc oxide and the eutectic solvent are introduced separately into the vulcanizable rubber. In other embodiments, zinc oxide and the eutectic solvent are premixed to form a zinc oxide masterbatch, which may comprise a solution of zinc oxide dissolved or otherwise dispersed in the eutectic solvent. The zinc oxide masterbatch can then be introduced into the vulcanizable rubber.

[0118] Mixed conditions

[0119] In one or more embodiments, the vulcanizable composition is prepared by first mixing the vulcanizable rubber with a eutectic solvent at a temperature of about 140°C to about 180°C, or in other embodiments, at a temperature of about 150°C to about 170°C. In some embodiments, after initial mixing, the composition (i.e., the masterbatch) is cooled to a temperature of less than 100°C, or in other embodiments, cooled to a temperature of less than 80°C, and a curing agent is added. In some embodiments, mixing is continued at a temperature of about 90°C to about 110°C, or in other embodiments, mixing is continued at a temperature of about 95°C to about 105°C, to prepare the final vulcanizable composition.

[0120] In one or more embodiments, the masterbatch mixing step or one or more sub-steps of the masterbatch mixing step can be characterized by a peak temperature achieved by the composition during mixing. This peak temperature may also be referred to as the dripping 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°C to about 200°C, in other embodiments from about 150°C to about 190°C, and in other embodiments from about 160°C to about 180°C.

[0121] Final mixing step

[0122] Following the masterbatch mixing step, a curing agent or curing agent system is introduced into the composition, and mixing continues to ultimately form a vulcanizable composition. This mixing step may be referred to as the final mixing step, the curing mixing step, or the production mixing step. The product obtained from this mixing step may be referred to as a vulcanizable composition.

[0123] In one or more embodiments, the final mixing step can be characterized by the peak temperature achieved by the composition during final mixing. Those skilled in the art will recognize that this temperature may also be referred to as the final dripping temperature. In one or more embodiments, the peak temperature of the composition during final mixing can be up to 130°C, in other embodiments up to 110°C, and in still other embodiments up to 100°C. In these or other embodiments, the peak temperature of the composition during final mixing can be from about 80°C to about 130°C, in other embodiments about 90°C to about 115°C, and in still other embodiments about 95°C to about 105°C.

[0124] mixing equipment

[0125] All components of a vulcanizable composition can be mixed using standard mixing equipment such as internal mixers (e.g., Banbury mixers or Brabender mixers), extruders, kneaders, and two-roll mills. Mixing can be performed individually or sequentially. As mentioned above, components can be mixed in a single stage, or in two or more stages in other embodiments. For example, in the first stage (i.e., the mixing stage), a masterbatch is prepared, which typically contains rubber components and fillers. Once the masterbatch is prepared, a vulcanizing agent can be introduced and mixed into the masterbatch in the final mixing stage, which is typically carried out at a relatively low temperature to reduce the chance of premature vulcanization. An additional mixing stage, sometimes referred to as re-mixing, can be employed between the masterbatch mixing stage and the final mixing stage.

[0126] Tire manufacturing

[0127] Vulcanizable compositions can be processed into tire parts using common tire manufacturing techniques, including standard rubber molding, forming, and curing techniques. Vulcanization is typically achieved by heating the vulcanizable composition in a mold; for example, it can be heated to approximately 140°C to approximately 180°C. The cured or crosslinked rubber composition, referred to as vulcanized rubber, typically contains a thermosetting three-dimensional polymer network. Other components, such as fillers and processing aids, can be uniformly dispersed throughout the crosslinked network. Pneumatic tires can be manufactured as discussed in U.S. Patent Nos. 5,866,171, 5,876,527, 5,931,211, and 5,971,046, which are incorporated herein by reference.

[0128] Properties of vulcanized rubber

[0129] As described above, the vulcanizable compositions of the present invention can be cured to prepare various tire components. These tire components include, but are not limited to, tire treads, tire sidewalls, belt layers, inner liners, and tread cores.

[0130] According to an aspect of the invention, the tire component (which may also be referred to as vulcanized rubber) is characterized by advantageous curing properties while containing a relatively low content of metal activators, such as zinc.

[0131] In one or more embodiments, the vulcanized rubber is characterized by containing less than 2 pbw of zinc per 100 pbw of rubber, less than 1 phr of zinc in other embodiments, and less than 0.7 pbw of zinc in other embodiments.

[0132] In one or more embodiments, the tire component is a tire tread. Although it contains only limited amounts of metal activators, such as zinc substances, as outlined in this specification, the tread is characterized by a 300% modulus greater than 3 MPa as measured by ASTM D-412 at room temperature, greater than 5 MPa in other embodiments, and greater than 7 MPa in other embodiments.

[0133] To demonstrate the operation of the invention, several vulcanizable compositions were subjected to the following experiments. The vulcanizable compositions were prepared using the ingredients and mixing order provided in the table below. Unless otherwise specified, all amounts are expressed in parts by weight per 100 parts by weight of rubber. Generally, the amounts and positions of zinc oxide and the eutectic solvent varied throughout the experiments. The table below also provides the results of some analytical tests performed on the resulting compositions and / or vulcanized rubber.

[0134] Formation of eutectic solvent I

[0135] A eutectic composition of choline chloride and urea is prepared by mixing one mole of choline chloride with two moles of urea at 100°C to form a eutectic solvent, which is believed to be a deep eutectic solvent and may be referred to as DES-I. DES-I is then cooled to room temperature under standard conditions.

[0136] Experiment I

[0137] In the first set of experiments, vulcanizable compositions were prepared using the rubber formulations and mixing sequence provided in Table I. The rubber formulations indicate those suitable for manufacturing tire treads. As shown in Table I, the mixing procedure was a three-step process comprising a masterbatch mixing step, a “re-mixing” step, and a final mixing step. Each mixing step was performed in a Banbury mixer. During masterbatch preparation, the mixer was operated at 75 rpm and a peak composition temperature of 160°C was achieved. At this point, the composition was dripped from the mixer and allowed to cool to below approximately 85°C. At this point, the composition, along with the components identified for the “re-mixing” stage, was then reintroduced into the mixer and mixed at 75 rpm, achieving a peak composition temperature of approximately 160°C. The composition was again dripped from the mixer and allowed to cool to below approximately 50°C. The composition was then again reintroduced into the mixer along with the components identified for the “final mixing” stage. Among these components were DES-I and zinc oxide, which were introduced separately as provided in Table II. Mixing continued at 40 rpm, with a peak composition temperature of approximately 100°C. The composition was then dripped from the mixer, and a sample was obtained from the composition for analytical testing purposes. The results of the analytical tests are provided in Table II.

[0138] Table I

[0139] Element phr Masterbatch SBR 70 BR 30 Carbon black (N134) 25 silicon dioxide 50 paraffin oil 10 wax 2 stearic acid 2 6PPD(AO) 1 Refining silicon dioxide 10 silane 6 final sulfur 1.7 DPG 0.5 CBS 1.5 ZnO variable DES-I variable

[0140] Rheometer measurements were performed using an MDR 2000 operating at the temperatures specified in the table. The tensile mechanical properties (maximum stress, modulus, elongation, and toughness) of the vulcanized rubber were measured using the standard procedure described in ASTM-D412. The dynamic rheological properties (e.g., tanδ) of the vulcanized rubber were obtained from temperature scan studies conducted over a range of approximately –80°C to approximately 80°C at 10 Hz.

[0141] Table II

[0142]

[0143] The data in Table II show that the loading of ZnO can be significantly reduced in the presence of a eutectic solvent.

[0144] Experiment II

[0145] In the second experiment, DES-I, prepared using the same procedure described above, was introduced into a vulcanizable material composition prepared using a two-stage mixing procedure. The ingredients used and the mixing order are provided in Table III. This rubber formulation indicates a rubber formulation that can be used to manufacture tire sidewalls.

[0146] As with previous experiments, the mixing process was conducted in a Banbury mixer. During masterbatch preparation, the mixer was operated at 75 rpm and a peak temperature of 160°C was achieved. At this point, the composition was dripped from the mixer and allowed to cool to below approximately 85°C. The composition was then reintroduced into the mixer along with the components identified for the “final mixing stage,” which comprise DES-I and zinc oxide in the amounts provided in Table IV. Mixing continued at 40 rpm, with a peak composition temperature of approximately 100°C.

[0147] Table III

[0148] Element Phr Masterbatch NR 40 BR 60 Carbon black (N550) 45 paraffin oil 6 wax 1 stearic acid 2 6PPD(AO) 2.5 TMQ 1.5 resin 2 final sulfur 1 CBS 1.2 ZnO variable DES-I variable

[0149] As with previous experiments, the samples were analyzed and tested, and the results are shown in Table IV.

[0150] Table IV

[0151]

[0152]

[0153] The data in Table IV show that the loading of ZnO can be significantly reduced in the presence of a eutectic solvent.

[0154] Experiment III

[0155] In the third experiment, DES-I, prepared using the same procedure described above, was introduced into a vulcanizable composition indicating a rubber formulation suitable for manufacturing tire liners. The mixing conditions were the same as those provided in Experiment II above. The components used and the mixing order are provided in Table V.

[0156] Table V

[0157] Element phr Masterbatch BIIR 100 Carbon black (N660) 50 paraffin oil 8 resin 7 stearic acid 2 final sulfur 0.5 MBTS 1.5 ZnO variable DES variable

[0158] As with previous experiments, the samples were analyzed and tested, and the results are shown in Table VI.

[0159] Table VI

[0160]

[0161]

[0162] In addition to MDR, mechanical properties, and rheological properties, the permeability of the vulcanized rubber was analyzed according to ASTM D-3985. Data in Table VI show that the ZnO loading can be significantly reduced in the presence of a eutectic solvent.

[0163] Experiment IV

[0164] In the fourth experiment, DES-I, prepared using the same procedure described above, was introduced into a vulcanizable composition indicating a rubber formulation suitable for manufacturing tire belt layers. The mixing conditions were the same as those provided in Experiment II above. The components used and the mixing order are provided in Table VII.

[0165] Table VII

[0166]

[0167]

[0168] As with previous experiments, the samples were analyzed and tested, and the results are shown in Table VIII.

[0169] Table VIII

[0170]

[0171] The data in Table VIII show that the loading of ZnO can be significantly reduced in the presence of a eutectic solvent.

[0172] Experiment V

[0173] In Experiment 5, DES-I, prepared using the same procedure described above, was introduced into a vulcanizable composition indicating a rubber formulation suitable for manufacturing tire treads. The mixing conditions were the same as those provided in Experiment II above, except that DES-I was introduced together with the masterbatch components, as shown in Table IX, which lists the components used and the mixing order. As in the previous experiments, the samples were analyzed, and the results are shown in Table IX.

[0174] Table IX

[0175]

[0176]

[0177] The data in Table IX show that the loading of ZnO can be significantly reduced in the presence of a eutectic solvent.

[0178] Formation of eutectic solvent II

[0179] The eutectic composition of choline chloride and malonic acid is prepared by mixing one mole of choline chloride with one mole of malonic acid at 100°C to form a eutectic solvent, which is believed to be a deep eutectic solvent and may be referred to as DES-II. DES-II is cooled to room temperature under standard conditions.

[0180] Experiment VI

[0181] In Experiment 6, DES-I prepared using the same procedure described above and DES-II prepared above were introduced into the vulcanizable composition provided in Table X. The mixing conditions were the same as those provided above for Experiment II, which lists the components used and the mixing order.

[0182] Table X

[0183] Element phr Masterbatch SBR 100 final stearic acid 2 sulfur 1.3 CBS 1.7 ZnO variable DES (urea) variable DES (malonic acid) variable

[0184] As with previous experiments, the samples were analyzed and tested, and the results are shown in Table XI.

[0185] Table XI

[0186]

[0187] The data in Table VIII show that the loading of ZnO can be significantly reduced in the presence of a eutectic solvent.

[0188] Various modifications and alterations without departing from the scope and spirit of the invention will be apparent to those skilled in the art. The invention should not be unduly limited to the exemplary embodiments shown herein.

Claims

1. A method for preparing a vulcanizable material composition, the method comprising: (i) Mixing vulcanizable rubber, a curing agent, a metal compound, and a eutectic composition to form a vulcanizable material composition. The metal compound is zinc oxide or a derivative thereof, magnesium hydroxide, iron oxide, or cobalt carboxylate, wherein the vulcanizable material composition comprises less than 2 parts by weight of the metal compound per 100 parts by weight of rubber, wherein the vulcanizable material composition comprises 2% to 15% by weight of the eutectic composition relative to the total weight of the eutectic composition and the metal compound present in the vulcanizable material composition. The eutectic composition therefrom is made of formula Cat + X - zY is defined, where Cat + X - It is choline chloride, and z refers to the combination with X. - The number of Y molecules that mix, react, or interact, and where Y is urea or malonic acid.

2. The method according to claim 1, wherein the metal compound is zinc oxide.

3. A vulcanized rubber comprising: A vulcanized rubber network comprising zinc oxide dispersed throughout the vulcanized rubber network, the vulcanized rubber network comprising less than 2 parts by weight of zinc oxide / 100 parts by weight of rubber, wherein the vulcanized rubber comprises a eutectic composition comprising choline chloride and urea or choline chloride and malonic acid, wherein the vulcanized rubber is a tire tread, and wherein the vulcanized rubber is characterized by a 300% modulus greater than 3 MPa, wherein the vulcanized rubber network comprises 2% to 15% by weight of the eutectic composition relative to the total weight of the eutectic composition and zinc oxide present in the vulcanized rubber network.

Images