WO2022125675A1

WO2022125675A1 - Methods of preparing a composite having elastomer and filler

Info

Publication number: WO2022125675A1
Application number: PCT/US2021/062427
Authority: WO
Inventors: Satyan CHOUDHARY; Ping Zhang; Dhaval A. Doshi; Martin C. Green; Frederick H. Rumpf
Original assignee: Beyond Lotus Llc
Priority date: 2020-12-09
Filing date: 2021-12-08
Publication date: 2022-06-16

Abstract

Disclosed herein are methods of preparing a composite comprising mixing solid elastomer with wet filler to form a composite comprising filler dispersed in the elastomer. The filler dispersed in the elastomer can comprise carbon black, silica, and/or silicon-treated carbon black. Also disclosed are composites made by the present methods and corresponding vulcanizates.

Description

METHODS OF PREPARING A COMPOSITE HAVING ELASTOMER AND FILLER

FIELD OF THE INVENTION

[0001] Disclosed herein are methods of mixing a solid elastomer with wet filler, in which the mixing is performed in the absence of coupling agents. Also disclosed are composites prepared from the present methods and corresponding vulcanizates.

BACKGROUND

[0002] There is always a desire in the rubber industry to develop methods to disperse filler in elastomer and it is especially desirable to develop methods which can do so efficiently with respect to filler dispersion quality, time, effort, and/or cost.

[0003] Numerous products of commercial significance are formed of elastomeric compositions wherein reinforcing filler is dispersed in any of various synthetic elastomers, natural rubber or elastomer blends. Carbon black and silica, for example, are widely used to reinforce natural rubber and other elastomers. It is common to produce a masterbatch, that is, a premixture of reinforcing filler, elastomer, and various optional additives, such as extender oil. Such masterbatches are then compounded with processing and curing additives and upon curing, generate numerous products of commercial significance. Such products include, for example, pneumatic and non-pneumatic or solid tires for vehicles, including the tread portion including cap and base, undertread, innerliner, sidewall, wire skim, carcass and others. Other products include, for example, engine mounts, bushings, conveyor belts, windshield wipers, rubber components for aerospace and marine equipment, vehicle track elements, seals, liners, gaskets, wheels, bumpers, anti-vibration systems and the like.

[0004] While there are a number of methods to incorporate filler into solid elastomer, there is a continuing need for new methods to achieve acceptable or enhanced elastomer composite dispersion quality and functionality from elastomer composite masterbatches, which can translate into acceptable or enhanced properties in the corresponding vulcanized rubber compounds and rubber articles. SUMMARY

[0005] One aspect is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a filler comprising carbon black and silica, wherein the carbon black is a wet carbon black comprising a liquid present in an amount of at least 20% by weight based on total weight of the wet carbon black, and

(b) in one or more mixing steps, mixing the at least the solid elastomer and the filler to form a mixture, and removing at least a portion of the liquid from the mixture by evaporation, wherein the mixing is performed in the substantial absence of sulfur- containing silane coupling agents; and

(c) discharging, from the mixer, the composite comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite and at least

60 wt.% of the filler dispersed in the elastomer is carbon black.

[0006] Another aspect is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a filler comprising carbon black and silica, wherein the carbon black is a wet carbon black comprising a liquid present in an amount of at least 20% by weight based on total weight of the wet carbon black; and

(b) in one or more mixing steps, mixing the at least the solid elastomer and the filler to form a mixture, and removing at least a portion of the liquid from the mixture by evaporation, wherein the mixing is performed in the substantial absence of sulfur- containing silane coupling agents;

(c) discharging, from the first mixer, the mixture comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein at least 60 wt.% of the filler dispersed in the elastomer is carbon black, the mixture has a liquid content that is reduced to an amount less than the liquid content at the beginning of step (b), and the mixture has a material temperature ranging from 100°C to 180°C; (d) mixing the mixture from (c) in a second mixer to obtain the composite; and

(e) discharging, from the second mixer, the composite having a liquid content of less than 3% by weight based on total weight of said composite.

[0007] Another aspect is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a wet filler comprising a filler and a liquid present in an amount ranging from 15% to 65% by weight based on total weight of the wet filler, and

(b) in one or more mixing steps, mixing the at least the solid elastomer and the wet filler to form a mixture, and removing at least a portion of the liquid from the mixture by evaporation, wherein the mixing is performed in the substantial absence of silane coupling agents; and

(c) discharging, from the mixer, the composite comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite and at least 60 wt.% of the filler dispersed in the elastomer is at least one of silica and Silicon-treated carbon black.

[0008] Another aspect is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a wet filler comprising a filler and a liquid present in an amount of at least 20% by weight based on total weight of the wet filler, and

(c) discharging, from the mixer, the composite comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite and at least 60 wt.% of the filler dispersed in the elastomer is Silicon-treated carbon black. [0009] Another aspect is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a wet filler comprising filler and a liquid present in an amount of at least 15% by weight based on total weight of the wet filler; and

(b) in one or more mixing steps, mixing the at least the solid elastomer and the wet filler to form a mixture, and removing at least a portion of the liquid from the mixture by evaporation, wherein the mixing is performed in the substantial absence of silane coupling agents;

(c) discharging, from the first mixer, the mixture comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein at least 60 wt.% of the filler dispersed in the elastomer is at least one of silica and Silicon-treated carbon black, the mixture has a liquid content that is reduced to an amount less than the liquid content at the beginning of step (b), and the mixture has a material temperature ranging from 100°C to 180°C;

(d) mixing the mixture from (c) in a second mixer to obtain the composite; and

DETAILED DESCRIPTION

[0010] Disclosed herein, in part, are methods of preparing or forming a composite by mixing a solid elastomer with a wet filler. Also disclosed herein, in part, are composites, vulcanizates, and articles formed therefrom.

[0011] When mixing fillers with elastomers, a challenge is to ensure the mixing time is long enough to ensure sufficient filler incorporation and dispersion before the elastomer in the mixture experiences high temperatures and undergoes degradation. In typical dry mix methods, the mix time and temperature are controlled to avoid such degradation and the ability to optimize filler incorporation and dispersion is often not possible. [0012] PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein, describes a mixing process with solid elastomer and a wet filler (e.g., comprising a filler and a liquid) to enable the batch time and temperature to be controlled beyond that attainable with known dry mixing processes. Other benefits may be attained, such as enhancing filler dispersion and/or facilitating rubber-filler interactions and/or improving rubber compound properties compared to conventionally mixed masterbatches when they are compounded and vulcanized. At least one of two properties can be improved, e.g., the ratio of tensile stress at 300% elongation to stress at 100% elongation (M300/M100), and the maximum tangent delta (tan 6) measured at 60°C. A higher M300/M100 value is thought to be related to improved tire wear resistance and a lower tan 6 value is thought to be related to improved energy efficiency of tires.

[0013] Without wishing to be bound by any theory, while such mixing of solid elastomer with wet filler can offer benefits, there is a potential of slippage inside a mixer due to the presence of the liquid. The slippage can result in inefficient mixing. For the mixing of wet carbon-based fillers, the replacement of some of the carbon-based filler with a silica-based filler may result in less slippage, which can increase mixing efficiency.

[0014] Disclosed herein are methods for mixing a filler comprising a wet filler with a solid elastomer in which the filler comprises at least silica and/or Silicon-treated carbon black. The silica and/or Silicon-treated carbon black can be the majority or minority of the filler by weight is incorporated into the solid elastomer, e.g., at least 5 wt.% of the filler dispersed in the elastomer is silica and/or Silicon-treated carbon black. Alternatively stated, at least 5 wt.% of the filler charged to the mixer (dry basis) is silica and/or Silicon-treated carbon black. In one aspect, the method comprises mixing a solid elastomer with a filler comprising wet carbon black and silica (wet or dry). In another aspect, the method comprises mixing a solid elastomer with a filler comprising wet silica and/or Silicon-treated carbon lack.

[0015] The composite formed can be considered a mixture or masterbatch (an uncured mixture of filler(s) and elastomer(s)). The composite formed can be, as an option, an intermediate product that can be used in subsequent rubber compounding and one or more vulcanization processes. The composite, prior to the compounding and vulcanization, can also be subjected to additional processes, such as one or more holding steps or further mixing step(s), one or more additional drying steps, one or more extruding steps, one or more calendaring steps, one or more milling steps, one or more granulating steps, one or more baling steps, one or more twin-screw discharge extruding steps, or one or more rubber working steps to obtain a rubber compound or a rubber article.

Carbon Black and Silica

[0016] Disclosed herein, in one aspect, are methods for mixing a filler comprising a wet carbon black with a solid elastomer in which silica is also incorporated into the solid elastomer. The resulting composite comprises carbon black dispersed in the solid elastomer where the carbon black is present in an amount of at least 60% by weight relative to the total weight of the filler (dry basis). The silica is present in the composite in minor amounts, e.g., 40% by weight or less, 30% by weight or less, 20% by weight or less relative to the total weight of the filler (dry basis).

[0017] When mixing silica with rubber, silane coupling agents are typically used to bind to both the silica surface and the rubber, thereby enhancing the silica-rubber interaction. The silane coupling contains silyl groups that can bind to the silica surface and sulfur groups that can bond to the rubber. Commonly used silane coupling agents include bis(3-triethoxysilylpropyl)tetrasulfane (TESPT) and bisftriethoxysilylpropyl] disulphide (TESPD), as well as certain mercaptosilanes. In the present methods the majority reinforcement filler is carbon black. Further, the use of a wet carbon black comprising a liquid enhances carbon black dispersion in an elastomer compared to mixing with nonwetted, (e.g., dry) carbon black, as disclosed in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein. As one of the purposes of adding silica is to, at least in part, overcome some of the mixing inefficiencies that arise from the presence of the liquid, the mixing can be performed in the substantial absence of sulfur- containing silane coupling agents.

[0018] Disclosed herein is a method of preparing a composite, comprising:

(a) charging a mixer with at least a solid elastomer and a filler comprising carbon black and silica, wherein the carbon black is a wet carbon black comprising a liquid present in an amount of at least 20% by weight based on total weight of the wet carbon black, and (b) in one or more mixing steps, mixing the at least the solid elastomer and the filler to form a mixture, and removing at least a portion of the liquid from the mixture by evaporation, wherein the mixing is performed in the substantial absence of sulfur- containing silane coupling agents; and

(c) discharging, from the mixer, the composite comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite and at least 60 wt.% of the filler dispersed in the elastomer is carbon black.

[0019] The methods for preparing a composite include the step of charging or introducing into a mixer at least a solid elastomer and a filler comprising wet carbon black and silica, e.g., a) one or more solid elastomers and b) a filler comprising wet carbon black and silica wherein the carbon black or at least a portion of the carbon black has been wetted with a liquid (wet carbon black) prior to mixing with the solid elastomer. The combining of the solid elastomer with wet carbon black forms a mixture during the mixing step(s). The method further includes, in one or more mixing steps, conducting said mixing wherein at least a portion of the liquid is removed by evaporation or an evaporation process that occurs during the mixing. The liquid of the wet filler is capable of being removed by evaporation (and at least a portion is capable of being removed under the claimed mixing conditions) and can be a volatile liquid, e.g., volatile at bulk mixture temperatures. For example, a volatile liquid can be distinguished from oils (e.g., extender oils, process oils) which can be present during at least a portion of the mixing as such oils are meant to be present in the composite that is discharged and thus, do not evaporate during a substantial portion of the mixing time.

[0020] In conventional mixing with silica fillers , the mixing is often performed in the presence of sulfur-containing silane coupling agents to improve the dispersion of silica and improve the interaction with the rubber. Sulfur-containing silane coupling agents for mixing silica with elastomers are well known in the art, examples of which include bis(3- triethoxysilylpropyl)tetrasulfane, bis(3-triethoxysilylpropyl)disulfane, 3-thiocyanatopropyl- triethoxy silane, gamma-mercaptopropyl-trimethoxy silane, gamma-mercaptopropyl- triethoxy silane, and zirconium dineoalkanolatodi(3-mercapto) propionato-O, N,N'-bis(2- methyl-2-nitropropyl)-l,6-diaminohexane, S-(3-(triethoxysilyl)propyl) octanethioate. In the present methods, the mixing is performed in the substantial absence of sulfur-containing silane coupling agents. "Substantial absence of sulfur-containing silane coupling agents" can refer to no more than 1.5 phr, no more than 1 phr, no more than 0.5 phr, or no more than 0.2 phr or 0.1 phr or 0 phr sulfur-containing silane coupling agent present in the mixture, e.g., mixture formed during the mixing.

[0021] The filler charged to the mixer can be a mixture of wet carbon black and wet silica and/or dry silica in any of the ratios disclosed herein, resulting in the filler dispersed in the composite comprising carbon black and silica. On a dry basis, the filler comprises carbon black in an amount of at least 60% by weight relative to the total weight of the filler, e.g., at least 70%, at least 80%, or at least 90% by weight, e.g., in an amount ranging from 60% to 95% by weight, from 60% to 90%, from 60% to 85%, from 60% to 80%, from 60% to 75%, from 60% to 70%, from 65% to 95% by weight, from 65% to 90%, from 65% to 85%, from 65% to 80%, from 65% to 75%, from 70% to 95% by weight, from 70% to 90%, from 70% to 85%, from 70% to 80%, from 75% to 95%, from 75% to 90%, from 75% to 85% by weight, from 80% to 95%, or from 80% to 90% by weight. The weight percentages refer to amounts relative to the total weight of the filler on a dry basis. The silica can be present in the blend in an amount (dry basis) of no more than 40% by weight, no more than 30% by weight, no more than 20% by weight, or no more than 10% by weight, e.g., the silica can be present in the blend in an amount ranging from 5% to 40% by weight, from 5% to 35%, from 5% to 30%, from 5% to 25%, from 5% to 20%, from 5% to 15%, 10% to 40%, from 10% to 35%, from 10% to 30%, from 10% to 25%, from 10% to 20%, from 15% to 40%, from 15% to 35%, from 15% to 30%, from 15% to 25%, from 20% to 40%, from 20% to 35%, or from 20% to 30% by weight, relative to the total weight of the filler on a dry basis. All of the filler loadings disclosed herein can refer to the targeted amount of carbon black and silica that is charged to the mixer and/or the amount of carbon black and silica that is present in the composite.

[0022] As an option, the filler can be only carbon black and silica, i.e., the filler consists of or consists essentially of carbon black and silica. Any weight ratio of carbon black and silica can be envisaged, e.g., the filler blend can contain 60 wt.% carbon black and 40 wt.% silica, or a blend of 70 wt.% carbon black and 30 wt.%, or a blend of 80 wt.% carbon black and 20wt.% silica, or other desired weight ranges and combinations of carbon black and silica.

[0023] As an option, the mixing can be performed in the presence of a silica coating agent. The silica surface is such that a number of ingredients present in a rubber mixture (e.g., curatives) can adsorb to the silica surface. In addition or alternatively, silica particles interact with each other during mixing. Either possibility can reduce the available silica surface and therefore reduces its functionality. Without wishing to be bound by any theory, the adsorption of a silica coating agent on the surface of silica during mixing could reduce the interaction between filler particles during the mixing and/or prevent adsorption of unwanted components on the surface. The reduced interaction can achieve one or more of the following: increase the dispersibility of silica in the rubber, reduce flocculation of silica in the composite that is formed, and/or improve processability and curing characteristics of a vulcanizate formed from the composite. For example, polyethylene glycol has been shown to effect scorch and cure behavior for dry mixed silica rubber compositions. The presence of a silica coating agent may improve tensile properties such as elongation at break.

[0024] The present silica coating agents are free of sulfur (e.g., less than 0.1 wt.% sulfur in the agent). The amounts of silica coating agent charged to the mixer is targeted to be an amount ranging from 0.5 phr to 10 phr in a mixture containing the solid elastomer and fillers, e.g., amounts ranging from 0.5 phr to 9 phr, from 0.5 phr to 8 phr, from 0. 5 phr to 7 phr, from 0.5 phr to 6 phr, from 0.5 phr to 6 phr, from 0.5 phr to 5 phr, from 0.5 phr to 4 phr, from 0.5 phr to 3 phr, from 1 phr to 10 phr, from 1 phr to 9 phr, from 1 phr to 8 phr, from 1 phr to 7 phr, from 1 phr to 6 phr, from 1 phr to 6 phr, from 1 phr to 5 phr, from 1 phr to 4 phr, or from 1 phr to 3 phr.

[0025] Silica coating agents can be selected from polyakylene glycols (e.g., polyethylene glycol and polypropylene glycol), polycarboxylic acids, alkylalkoxysilanes, bifunctional silanes, alkane diols, fatty acid esters of sugars, polyamines, polyimines, and hydroxyalkylamines.

[0026] As an option, the silica coating agent can be selected from polyalkylene glycols, e.g., at least one of polyethylene glycol and polypropylene glycol. The surface of silica is highly polar, which can render silica susceptible to adsorption by curatives. The amount of polyethylene glycol and/or polypropylene glycol charged to the mixer can range from 0.5 phr to 10 phr, e.g., from 0.5 phr to 5 phr, from 0.5 phr to 3 phr, from 1 phr to 10 phr, from 1 phr to 5 phr, or from 1 phr to 3 phr. Various polyethylene glycols are known in the art and can have an average molecular weight (weight average molecular weight) ranging from 1,000 to 20,000, e.g, from 1,000 to 15,000, from 1,000 to 10,000, from 1,000 to 9,000, from 1,000 to 8,000, from 1,000 to 7,000, from 1,000 to 6,000, from 1,000 to 5,000, from 2,000 to 20,000, from 2,000 to 15,000, from 2,000 to 10,000, from 2,000 to 9,000, from 2,000 to 8,000, from 2,000 to 7,000, from 2,000 to 6,000, or from 2,000 to 5,000, from 3,000 to 20,000, from 3,000 to 15,000, from 3,000 to 10,000, from 3,000 to 9,000, from 3,000 to 8,000, from 3,000 to 7,000, from 3,000 to 6,000, from 5,000 to 20,000, from 5,000 to 15,000, or from 5,000 to 10,000. Polypropylene glycols can have a weight average molecular weight ranging from 1,000 to 30,000, from 1,000 to 25,000, 5,000 to 30,000, from 5,000 to 25,000, or any of the molecular weight ranges recited above for polyethylene glycol.

[0027] As an option, the silica coating agent can be selected from polycarboxylic acids, e.g., compounds having at least two carboxylic acid groups including linear, branched, saturated or unsaturated C2-C20 aliphatic or aromatic polycarboxylic acids. Polycarboxylic acids also include C2-C16, C2-C14, or C2-C12 polycarboxylic acids. Examples include succinic acid, adipic acid, glutaric acid, ethylsuccinic acid, methylglutaric acid, oxalic acid and citric acid. Mixtures of different polycarboxylic acids can also be used. Other examples of polycarboxylic acids are included in U.S. Patent No. 10,259,7125, and U.S. Patent Publication No. 2017/0015830, the disclosures of which are incorporated by reference herein.

[0028] As an option, the silica coating agent can be selected from alkylalkoxysilanes having the formula (R¹)_nSi(OR²)4-n, in which n is an integer selected from 1- 3, R¹ and R² are each independently selected from C1-C20 aliphatic and aromatic hydrocarbon groups (e.g., a C1-C14, C1-C12, C1-C10 aliphatic or aromatic hydrocarbon group). For example, R¹ can be selected from methyl, ethyl, propyl, isopropyl, n-butyl or t-butyl, cyclohexyl, octyl, n-octadecyl, n-hexadecyl, and phenyl and R² can be selected from hydroxyl, methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, or phenyloxy. Other examples are disclosed in U.S. Patent No. 5,780,538 and U.S. Patent Publication No. 2009/0186961, the disclosures of which are incorporated by reference herein.

[0029] As an option, the silica coating agent can be selected from bifunctional silanes. Bifunctional silanes can have a first functional group selected from alkylalkoxysilyl groups, and a second functional group selected from -NR⁵NR⁶, epoxy, acrylate, vinyl, allyl, hexenyl, glycidoxy, and meth(acryloxy). The alkylalkoxysilyl groups can have the formula (R¹)_nSi(OR²)3 n, where n is 1 or 2, and R1 and R2 can be defined as above. The R⁵ and R⁶ of the -NR⁵NR⁶ group can be independently selected from H and C1-C20 aliphatic and aromatic hydrocarbon groups, as defined for R¹ above. The two functional groups can be bonded to a conjugated diene (e.g., butadiene)/vinyl aromatic (e.g., styrene) hydrocarbon copolymer. Exemplary bifunctional silanes include those described in EP661298B1, the disclosure of which is incorporated herein by reference.

[0030] As an option, the silica coating agent can be selected from alkane diols, e.g., C1-C20 alkane diols, linear or branched, e.g., 1,2-pentanediol, 2-methyl-2-propyl-l,3- propanediol, 2-butyl-2-ethyl-l,3- propanediol. 2-sec-butyl-2-methyl-l,3-propanediol, and trimethylolpropane (2-ethyl-2-hydroxymethyl-l,3- propanediol). Other alkane diols are described in U.S. Patent No. 5,717,022, the disclosure of which is in incorporated herein by reference.

[0031] As an option, the silica coating agent can be selected from fatty acid esters of sugars, i.e., hydrogenated or non-hydrogenated sugars. The sugars can be C5 or Cg sugars (e.g., sorbitose, mannitose, and arabinose) and can include at least three hydroxyl or polyoxyethylene groups and 1-3.5 ester groups, i.e., -O-C(O)-R⁷, where R⁷ can be selected from C10 to C22 saturated and unsaturated fatty acids. Exemplary fatty acids include stearic, lauric, palmitic, and oleic fatty acids. For example, the fatty acid esters of sugars can be sorbitan stearate or sorbitan oleates (e.g., sorbitan monooleate or sorbitan tri-oleate). Other exemplary fatty acid esters of sugars include those described in U.S. Patent No. 6,525,118, the disclosure of which is incorporated herein by reference.

[0032] As an option, the silica coating agent can be selected from polyamines. For example, primary polyamine compounds can have the formula H2N-R⁸-(NH2)m or H2N-R⁹-R¹⁰-(R¹¹NH2)m, where R⁸, R⁹, R¹⁰, and R¹¹ are independently selected from C1-C20 alkylenes, C5-C24 cycloalkylenes, Cg-Cis arylenes, and C7-C25 aralkylenes. Exemplary polyamines include 1,4-diaminocyclohexane, 1,2-diaminocyclohexane, N,N-bis(2- aminoeethyle)ethane-l,2-diamine, 1,8-octamethylenediamine, and 1,6- hexamethylenediamine. Other exemplary polyamines are described in U.S. Patent Publication No. 2012/0149818, the disclosure of which is incorporated herein by reference.

[0033] As an option, the silica coating agent can be selected from polyimines. For example polyimines can have the formula (R¹²)(R¹³)C=N-R⁸-[(N=C(R¹⁴)(R¹⁵)]_m or (R¹²)(R¹³)C=N-R⁸- R⁹-[(R¹⁰-N=C(R¹⁴)(R¹⁵)]_m, where R¹²- R¹⁵ are each independently selected from C1-C20 alkyls, C5-C24 cycloalkyls, Cg-Cis aryls, and m and R⁸- R¹⁰ are as defined above. Specific examples include N,N'-Bis(4-methylpentan-2-ylidene)hexane-l,6-diamine, N,N'- bis(4-methylpentan-2-ylidene)cyclohexane-l,4-diamine. Other exemplary polyimines are described in U.S. Patent No. 9,566,828, the disclosure of which is incorporated herein by reference.

[0034] As an option, the silica coating agent can be selected from hydroxyalkylamines. As an option, the silica coating agent can be selected from compounds having the formula HO-R¹⁶-NR¹⁷R¹⁸, wherein R¹⁶ is selected from a C1-C20 saturated or unsaturated aliphatic hydrocarbon-based group (e.g., a linear or branched alkylene chain, such as a linear or branched C1-C20 or Ci-Cs or Ci-Ce or C1-C3 alkylene chain), and R¹⁷ and R¹⁸ are each independently selected from hydrogen, a C1-C12 saturated or unsaturated aliphatic hydrocarbon-based group, or a group having the formula HO— R¹⁶. As an option, both R¹⁷ and R¹⁸ are each hydrogen. Such compounds are disclosed in U.S. Patent No. 8,530,562, the disclosure of which is incorporated herein by reference. As another option, the hydroxyalkylamine is selected from triethanolamine, e.g., as described in U.S. Patent Publication No. 2018/0327573, the disclosure of which is incorporated herein by reference.

Silica and/or Silicon-Treated Carbon Black

[0035] Disclosed herein, in another aspect, are methods for mixing a solid elastomer with a wet filler comprising a filler comprising at least 60 wt.% of silica and/or Silicon-treated carbon black (dry basis relative to the total weight of the filler). The resulting composite comprises the filler dispersed in the solid elastomer where at least one of silica and Silicon-treated carbon black is present in an amount of at least 60% by weight relative to the total weight of the filler (dry basis).

[0036] Conventional mixing can employ silane coupling agents, such as alkylalkoxysilanes, bifunctional silanes, or sulfur-containing silane coupling agents, each of which are described above.

[0037] In the present methods, the mixing is performed in the substantial absence of silane coupling agents, e.g., collectively sulfur-containing silane coupling agents, alkylalkoxysilanes, and bifunctional silanes. When silica is the filler, "substantial absence of silane coupling agents" can refer to no more than 1.5 phr, no more than 1 phr, no more than 0.5 phr, no more than 0.2 phr, no more than 0.1 phr or 0 phr of silane coupling agents that are present in the mixture, e.g., mixture formed during the mixing. When Silicon- treated carbon black is the filler, "substantial absence of silane coupling agents" can refer to no more than no more than 0.5 phr, no more than 0.4 phr, no more than 0.3 phr, no more than 0.2 phr, no more than 0.1 phr, no more than 0.05 phr, or 0 phr of silane coupling agents that are present in the mixture, e.g., mixture formed during the mixing.

[0038] The filler charged to the mixer (e.g., dispersed in the composite) comprises at least one of silica and/or Silicon-treated carbon black in an amount of at least 60% by weight based on total weight of the filler on a dry basis. Thus, the filler can comprise at least 60 wt.% silica, at least 60 wt.% Silicon-treated carbon black, or at least 60 wt.% of a combination of silica and Silicon-treated carbon black. As an option, on a dry basis, the filler can comprise silica and/or Silicon-treated carbon black in an amount of at least 60% by weight relative to the total weight of the filler, e.g., at least 70%, at least 80%, or at least 90% by weight, e.g., in an amount ranging from 60% to 95% by weight, from 60% to 90%, from 60% to 85%, from 60% to 80%, from 60% to 75%, from 60% to 70%, from 65% to 95% by weight, from 65% to 90%, from 65% to 85%, from 65% to 80%, from 65% to 75%, from 70% to 95% by weight, from 70% to 90%, from 70% to 85%, from 70% to 80%, from 75% to 95%, from 75% to 90%, from 75% to 85% by weight, from 80% to 95%, or from 80% to 90% by weight. The weight percentages refer to amounts relative to the total weight of the filler on a dry basis. [0039] For combinations of silica and Silicon-treated carbon black, the filler can comprise silica in an amount of at least 60% by weight, at least 70% by weight, or other amounts disclosed herein (dry basis) and Silicon-treated carbon black in an amount of no more than 40% by weight, no more than 30% by weight, no more than 20% by weight, or no more than 10% by weight, e.g., the filler can comprise the Silicon-treated carbon black in an amount ranging from 1% to 40% by weight, from 1% to 35%, from 1% to 30%, from 1% to 25%, from 1% to 20%, from 1% to 15%, from 1% to 10%, from 1% to 5%, from 5% to 40% by weight, from 5% to 35%, from 5% to 30%, from 5% to 25%, from 5% to 20%, from 5% to 15%, 10% to 40%, from 10% to 35%, from 10% to 30%, from 10% to 25%, from 10% to 20%, from 15% to 40%, from 15% to 35%, from 15% to 30%, from 15% to 25%, from 20% to 40%, from 20% to 35%, or from 20% to 30% by weight, relative to the total weight of the filler on a dry basis. As another option, the filler can comprise Silicon-treated carbon black in an amount of at least 60% by weight, at least 70% by weight, or other amounts disclosed herein (dry basis) and silica in an amount of no more than 40% by weight, no more than 30% by weight, no more than 20% by weight, or no more than 10% by weight, e.g., the filler can comprise silica in an amount ranging from 1% to 40% by weight, from 1% to 35%, from 1% to 30%, from 1% to 25%, from 1% to 20%, from 1% to 15%, from 1% to 10%, from 1% to 5%, from 5% to 40% by weight, from 5% to 35%, from 5% to 30%, from 5% to 25%, from 5% to 20%, from 5% to 15%, 10% to 40%, from 10% to 35%, from 10% to 30%, from 10% to 25%, from 10% to 20%, from 15% to 40%, from 15% to 35%, from 15% to 30%, from 15% to 25%, from 20% to 40%, from 20% to 35%, or from 20% to 30% by weight, relative to the total weight of the filler on a dry basis. As yet another option the ratio of silica to Silicon-treated carbon black can range from 1:99 to 99:1 or from 5:95 to 95:5 or from 10:90 to 90:10 or from 25:75 to 75:25 or from 45:55 to 55:45. All of the filler loadings disclosed herein can refer to the targeted amount of silica and/or Silicon-treated carbon black that is charged to the mixer and/or the amount of silica and/or Silicon-treated carbon black that is present in the composite.

[0040] As an option, the filler can be only silica, only Silicon-treated carbon black, or silica and Silicon-treated carbon black, i.e., the filler consists of or consists essentially of silica, consists of or consists essentially of Silicon-treated carbon black, or filler consists of or consists essentially of silica and Silicon-treated carbon black. [0041] As an option, where the wet filler comprises silica and/or Silicon-treated carbon black, the mixing can be performed in the presence of a filler coating agent. The surface of silica and/or Silicon-treated carbon black, and optionally one or more additional fillers, is such that a number of ingredients present in a rubber mixture (e.g., curatives) can adsorb to the filler surface. In addition or alternatively, silica and/or Silicon-treated carbon black can interact with each other during mixing. Either possibility can reduce the available filler surface and therefore reduces its functionality.

[0042] Filler coating agents can be selected from polyakylene glycols (e.g., polyethylene glycol and polypropylene glycol), polycarboxylic acids, alkane diols, fatty acid esters of sugars, polyamines, polyimines, and hydroxyalkylamines, each of which are described above. Suitable loadings for silica coating agents can also apply to filler coating agents.

Filler(s)

[0043] The filler charged to the mixer can be a mixture of wet filler in any of the ratios disclosed herein. Typically, fillers contain no or small amounts of liquid (e.g. water or moisture) adsorbed onto its surfaces. Such fillers, are referred to herein as dry or nonwetted fillers. For example, carbon black can have 0 wt.%, or 0.1 wt.% to 1 wt.% or up to 3 wt.% or up to 4 wt.% of liquid. Wet carbon black is achieved by wetting with a liquid such that the wet carbon black contains the liquid in an amount of at least 20% by weight, relative to the total weight of the wet carbon black. As another example, precipitated silica can have a liquid (e.g., water or moisture) content of from 4 wt.% to 7 wt.% liquid, e.g., from 4 wt.% to 6 wt.% liquid. Wet silica comprises a liquid in an amount ranging from 15% to 65% by weight, relative to the total weight of the wet silica. Wet Silicon-treated carbon black comprises a liquid in an amount of at least 20% by weight, by weight relative to the total weight of the wet Silicon-treated carbon black.

[0044] For the present filler, e.g., wet carbon black, and/or wet silica and/or wet Silicon-treated carbon black, liquid or additional liquid can be added to the filler and is present on a substantial portion or substantially all the surfaces of the filler, which can include inner surfaces or pores accessible to the liquid. Thus, sufficient liquid is provided to wet a substantial portion or substantially all of the surfaces of the filler prior to mixing with solid elastomer. During mixing, at least a portion of the liquid can also be removed by evaporation as the wet filler (wet carbon black, and/or wet silica and/or wet Silicon-treated carbon black) is being dispersed in the solid elastomer, and the surfaces of the filler can then become available to interact with the solid elastomer.

[0045] Wet carbon black can have a liquid content of at least 20% by weight relative to the total weight of the wet filler, e.g., at least 25%, at least 30%, at least 40%, at least 50% by weight, or from 20% to 99%, from 20% to 95%, from 20% to 90%, from 20% to 80%, from 20% to 70%, from 20% to 60%, from 30% to 99%, from 30% to 95%, from 30% to

90%, from 30% to 80%, from 30% to 70%, from 30% to 60%, from 40 % to 99%, from 40% to

95%, from 40% to 90%, from 40% to 80%, from 40% to 70%, from 40% to 60%, from 45 % to

99%, from 45% to 95%, from 45% to 90%, from 45% to 80%, from 45% to 70%, from 45% to

60%, from 50% to 99%, from 50% to 95%, from 50% to 90%, from 50% to 80%, from 50% to

70%, or from 50% to 60% by weight, relative to the total weight of the wet filler.

[0046] Where the wet filler is silica, the wet filler can have a liquid content ranging from 15% to 65% by weight relative to the total weight of the wet filler, e.g., from 20% to 65%, from 20% to 60%, from 30% to 65%, from 30% to 60%, from 40% to 65%, from 40% to 60%, from 45% to 65%, from 45% to 60%, from 50% to 65%, or from 50% to 60% by weight, relative to the total weight of the wet filler.

[0047] As an option, the wet carbon black and optionally wet silica can have liquid present in an amount of from about 25 wt.% to about 75 wt.%, e.g., from about 30% to about 75%, from about 40% to about 75%, from about 45% to about 75%, from about 50% to about 75%, from about 30% to about 70%, from about 40% to about 70%, from about 45% to about 70%, from about 50% to about 70%, from about 30% to about 65%, from about 40% to about 65%, from about 45% to about 65%, from about 50% to about 65%, from about 30% to about 60% by weight, from about 40% to about 60%, from about 45% to about 60%, or from about 50% to about 60% by weight, based on the weight of the total wet filler. If added as separate charges, or prior to forming a mixture of wet fillers, the liquid content of the carbon black and silica can be the same or different, so long as the liquid content of the total amount of wet filler charged to the mixer is at least 20% by weight, or other amounts disclosed herein. [0048] Where the wet filler comprises Silicon-treated carbon black (e.g., at least 50 wt.%, at least 60%, at least 70%, at least 80%, at least 90%, at least 95% Silicon-treated carbon black and optionally silica), the wet filler can have a liquid content of at least 20% by weight relative to the total weight of the wet filler, e.g., at least 25%, at least 30%, at least 40%, at least 50% by weight, or from 20% to 99%, from 20% to 95%, from 20% to 90%, from 20% to 80%, from 20% to 70%, from 20% to 60%, from 30% to 99%, from 30% to 95%, from 30% to 90%, from 30% to 80%, from 30% to 70%, from 30% to 60%, from 40 % to 99%, from 40% to 95%, from 40% to 90%, from 40% to 80%, from 40% to 70%, from 40% to 60%, from 45 % to 99%, from 45% to 95%, from 45% to 90%, from 45% to 80%, from 45% to 70%, from 45% to 60%, from 50% to 99%, from 50% to 95%, from 50% to 90%, from 50% to 80%, from 50% to 70%, or from 50% to 60% by weight, relative to the total weight of the wet filler.

[0049] As an option, the wet filler is silica and the wet silica can have liquid present in an amount ranging from 20% to 65%, from 25% to 65%, from 30% to 65%, from 40% to 65%, from 45% to 65%, from 50% to 65%, from 20% to 60%, from 25% to 60%, from 30% to 60%, from 40% to 60%, from 45% to 60%, or from 50% to 60% by weight, based on the weight of the total wet filler. If added as separate charges with at least one additional filler, or prior to forming a mixture of wet fillers, the liquid content of the wet silica and at least one additional filler can be the same or different, so long as the liquid content of the total amount of wet filler charged to the mixer ranges from 15% to 65%, or other amounts disclosed herein. As an option, the wet filler is Silicon-treated carbon black and the wet Silicon-treated carbon black can have liquid present in an amount of from 25% to 75%, e.g., from 30% to 75%, from 40% to 75%, from 45% to 75%, from 50% to 75%, from 30% to 70%, from 40% to 70%, from 45% to 70%, from 50% to 70%, from 30% to 65%, from 40% to 65%, from 45% to 65%, from 50% to 65%, from 30% to 60%, from 40% to 60%, from 45% to 60%, or from 50% to 60% by weight, based on the weight of the total wet filler, or any other amounts disclosed herein.

[0050] Liquid content of filler can be expressed as weight percent: 100* [mass of liquid]/[mass of liquid + mass of dry filler]. As another option, the amount of liquid can be determined based on the oil adsorption number (OAN) of the filler, where OAN is determined based on ASTM D2414. OAN is a measure of filler structure and can be used in determining the amount of liquid to wet the filler. For example, a wet filler such as a wet carbon black or wet silica (e.g., precipitated silica) or wet Silicon-treated carbon black can have a liquid content determined according to the equation: k* OAN/(100+OAN) * 100. In one embodiment, k ranges from 0.3 to 1.1, or from 0.5 to 1.05, or from 0.6 to 1.1, or from 0.7 to 1.1, or from 0.8 to 1.1, or from 0.9 to 1.1, or from 0.6 to 1.0, or from 0.7 to 1.0, or from 0.8 to 1.0, or from 0.8 to 1.05, or from 0.9 to 1.0, or from 0.95 to 1, or from 0.95 to 1.1, or from 1.0 to 1.1. As an option, the wet filler has a liquid content ranging from 20% to 80%, from 30% to 70%, from 30% to 60%, from 40% to 70%, or from 40% to 60% by weight.

[0051] As one option a wet co-pellet of carbon black and silica can be charged to the mixer. A blend of carbon black and silica can be pelletized in the presence of water, where the pelletizing process is described in further detail herein. In any of these co-pellet options, the co-pellet can further comprise at least one additional filler, as described herein. Alternatively, separate charges of wet carbon black and silica (e.g., wet silica or non-wetted silica and optionally at least one additional filler) can be added to the mixer.

[0052] As another option a wet co-pellet of silica and/or Silicon-treated carbon black and/or at least one additional filler (e.g., carbon black) can be charged to the mixer. A blend of silica and/or Silicon-treated carbon black and/or at least one additional filler can be pelletized in the presence of water, where the pelletizing process is described in further detail herein. Alternatively, separate charges of wet silica and/or Silicon-treated carbon black and at least one additional filler (e.g., wet filler or non-wetted filler) can be added to the mixer.

[0053] As an option, the wet filler has the consistency of a solid. As an option, a dry filler is wetted only to an extent such that the resulting wet filler maintains the form of a powder, particulates, pellet, cake, or paste, or similar consistency and/or has the appearance of a powder, particulates, pellet, cake, or paste. The wet filler does not flow like a liquid (at zero applied stress). As an option, the wet filler can maintain a shape at 25°C when molded into such a shape, whether it be the individual particles, agglomerates, pellets, cakes, or pastes. The wet filler is not a composite made by a liquid masterbatch process and is not any other pre-blended composite of filler dispersed in a solid elastomer (from elastomer in a liquid state) in which the elastomer is the continuous phase. The wet filler is not a slurry of filler and does not have the consistency of a liquid or slurry. [0054] The liquid used to wet the filler (carbon black and/or silica and/or Silicon- treated carbon black and optionally at least one additional filler) can be, or include, an aqueous liquid, such as, but not limited to, water. The liquid can include at least one other component, such as, but not limited to, a base(s), an acid(s), a salt(s), a solvent(s), a surfactant(s), and/or a processing aid(s) and/or any combinations thereof. More specific examples of the component are NaOH, KOH, acetic acid, formic acid, citric acid, phosphoric acid, sulfuric acid, or any combinations thereof. For example, the base can be selected from NaOH, KOH, and mixtures thereof, or the acids can be selected from acetic acid, formic acid, citric acid, phosphoric acid, or sulfuric acid, and combinations thereof. The liquid can be or include a solvent(s) that is immiscible with the elastomer used (e.g., alcohols such as ethanol). Alternatively, the liquid consists of from about 80 wt.% to 100 wt.% water or from 90 wt.% to 99 wt.% water based on the total weight of the liquid.

[0055] As another option, other fillers in addition to carbon black and/or silica and/or Silicon-treated carbon black may be present. For example, the filler can comprise at least carbon black in an amount of at least 60% by weight, silica, and at least one additional filler. As another example, the filler can comprise at least one of silica and Silicon-treated carbon black in an amount of at least 60% by weight and at least one additional filler.

[0056] The at least one additional filler in general, can be any conventional filler used with elastomers such as reinforcing fillers. The filler can be particulate or fibrous or plate-like. For example, a particulate filler is made of discrete bodies. Such fillers can often have an aspect ratio (e.g., length to diameter) of 3:1 or less, or 2:1 or less, or 1.5:1 or less. Fibrous fillers can have an aspect ratio of, e.g., 2:1 or more, 3:1 or more, 4:1 or more, or higher. Typically, fillers used for reinforcing elastomers have dimensions that are microscopic (e.g., hundreds of microns or less) or nanoscale (e.g., less than 1 micron). In the case of carbon black, the discrete bodies of particulate carbon black refer to the aggregates or agglomerates formed from primary particles, and not to the primary particles themselves. In other embodiments, the filler can have a platelike structure such as graphenes and reduced graphene oxides.

[0057] The at least one additional filler can be selected from carbonaceous materials, carbon black, nanocellulose, lignin, clays, nanoclays, metal oxides, metal carbonates, pyrolysis carbon, reclaimed carbon, recovered carbon black (e.g., as defined in ASTM D8178-19, rCB), graphenes, graphene oxides, reduced graphene oxide (e.g., reduced graphene oxide worms as disclosed in PCT Publ. No. WO 2019/070514A1, the disclosure of which is incorporated by reference herein), or densified reduced graphene oxide granules (as disclosed in U.S. Prov. Appl. No. 62/857,296, filed June 5, 2019, and PCT Publ. No. 2020/247681, the disclosures of which are incorporated by reference herein), carbon nanotubes, single-wall carbon nanotubes, multi-wall carbon nanotubes, or combinations thereof, or corresponding coated materials (e.g., Silicon-treated carbon black) or chemically- treated materials thereof (e.g., chemically-treated carbon black). Other suitable fillers include carbon nanostructures (CNSs, singular CNS), a plurality of carbon nanotubes (CNTs) that are crosslinked in a polymeric structure by being branched, e.g., in a dendrimeric fashion, interdigitated, entangled and/or sharing common walls with one another. CNS fillers are described in U.S. Pat. No. 9,447,259, and PCT Appl. No. PCT/US2021/027814, the disclosures of which are incorporated by reference herein. Blends of additional fillers can also be used, e.g., blends of silica and carbon black, silica and Silicon-treated carbon black, and carbon black and Silicon-treated carbon black. The filler can be chemically treated (e.g. chemically treated carbon black, chemically treated silica, Silicon-treated carbon black) and/or chemically modified. The filler can be or include carbon black having an attached organic group(s). The filler can have one or more coatings present on the filler (e.g. silicon- coated materials, silica-coated material, carbon-coated material). The filler can be oxidized and/or have other surface treatments. There is no limitation with respect to the type of filler (e.g., silica, carbon black, or other filler) that can be used.

[0058] As mentioned previously, fibrous fillers can also be incorporated in the methods disclosed herein, including natural fibers, semi-synthetic fibers, and/or synthetic fibers (e.g., nanosized carbon filaments), such as short fibers disclosed in PCT Publ. No. WO 2021/153643, the disclosure of which is incorporated by reference herein. Other fibrous fillers include poly(p-phenylene terephthalamide) pulp, commercially available as Kevlar® pulp (Du Pont).

[0059] The at least one additional filler can include bio-sourced or bio-based materials (derived from biological sources), recycled materials, or other fillers considered to be renewable or sustainable include hydrothermal carbon (HTC, where the filler comprises lignin that has been treated by hydrothermal carbonization as described in U.S. Pat. Nos. 10,035,957, and 10,428,218, the disclosures of which are incorporated by reference, herein), rice husk silica, carbon from methane pyrolysis, engineered polysaccharide particles, starch, siliceous earth, crumb rubber, and functionalized crumb rubber. Exemplary engineered polysaccharides include those described in U.S. Pat. Publ. Nos. 2020/0181370 and 2020/0190270, the disclosures of which are incorporated herein by reference. For example, the polysaccharides can be selected from: poly alpha-1, 3-glucan; poly alpha-1, 3-1, 6-glucan; a water insoluble alpha-(l, 3-glucan) polymer having 90% or greater a-l,3-glycosidic linkages, less than 1% by weight of alpha-1, 3, 6-glycosidic branch points, and a number average degree of polymerization in the range of from 55 to 10,000; dextran; a composition comprising a poly alpha-1, 3-glucan ester compound; and waterinsoluble cellulose having a weight-average degree of polymerization (DPw) of about 10 to about 1000 and a cellulose II crystal structure.

[0060] As an option, the at least one additional filler can be present in an amount of no more than 40%, no more than 30% by weight, no more than 20% by weight, no more than 10% by weight, no more than 5% by weight, or no more than 1% by weight, e.g., from 1% to 40% by weight, from 1% to 30%, from 1% to 20%, from 1% to 10%, or from 1% to 5% by weight. For example, the filler can comprise carbon black in an amount of at least 60% by weight, silica in an amount of no more than 35% or no more than 30% by weight, and the at least one additional filler (e.g. Silicon-treated carbon black) in an amount ranging from 1% to 40%, from 1% to 30%, from 1% to 20%, from 1% to 10% or from 1% to 5% by weight relative to the total weight of filler on a dry basis. As another example, the filler can comprise silica and/or Silicon-treated carbon black in an amount of at least 60% by weight, and the at least one additional filler (e.g. carbon black) in an amount ranging from 1% to 40%, from 1% to 30%, from 1% to 20%, from 1% to 10% or from 1% to 5% by weight relative to the total weight of filler on a dry basis.

[0061] In addition to the wet filler (wet carbon black and/or wet silica and/or Silicon-treated carbon black), as an option, the mixture can further include one or more nonwetted filler (e.g., any of the fillers as described herein, such as dry filler, such as a filler having no more than 10% liquid by weight.) When non-wetted filler is present, the total amount of filler can be such that at least 50% or at least 60%, at least 70%, at least 80 %, at least 90%, at least 95% by weight of the total weight of filler is a wet filler, such as from 50% to 99%, from 60% to 99%, from 70% to 99%, from 80% to 99%, from 90% to 99%, or from 95% to 99% of the total amount of filler can be wet filler, with the balance of the filler being in a non-wetted state or not being considered a wet filler.

[0062] The amount of filler (e.g. wet carbon black and/or wet silica and/or Silicon- treated carbon black and optionally at least one additional filler) that is loaded into the mixture can be targeted (on a dry weight basis) to be at least 20 phr, at least 30 phr, at least 40 phr, or range from 20 phr to 250 phr, from 20 phr to 200 phr, from 20 phr to 180 phr, from 20 phr to 150 phr, from 20 phr to 100 phr, from 20 phr to 90 phr, from 20 phr to 80 phr, 30 phr to 200 phr, from 30 phr to 180 phr, from 30 phr to 150 phr, from 30 phr to 100 phr, from 30 phr to 80 phr, from 30 phr to 70 phr, 40 phr to 200 phr, from 40 phr to 180 phr, from 40 phr to 150 phr, from 40 phr to 100 phr, from 40 phr to 80 phr, from 35 phr to 65 phr, or from 30 phr to 55 phr or other amounts within or outside of one or more of these ranges. The above phr amounts can also apply to filler dispersed in the elastomer (filler loading). Other filler types, blends, combinations, etc. can be used, such as those disclosed in are disclosed in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0063] The filler can be or include at least one of wet carbon black and/or wet silica and/or wet Silicon-treated carbon black in the form of pellets, powder, granules, and/or agglomerates. Wet carbon black can be in the form of fluffy powder. Wet carbon black or wet silica can be formed into pellets, granules, or agglomerates in, e.g., a pelletizer, a fluidized bed or other equipment to make the wet filler.

[0064] A filler that includes at least one of wet carbon black and/or wet silica and/or wet Silicon-treated carbon black can be one or more of the following: never-dried filler; and/or never-dried filler pellets; and/or dried filler pellets that have been rewetted, such as with water in a pelletizer; and/or dried filler pellets that have been ground and then rewetted with water in a pelletizer; and/or dried filler pellets combined with water; and/or fluffy powder, granules, or agglomerates combined with water.

[0065] In typical carbon black manufacturing, carbon black is initially prepared as dry, fine particulate (fluffy) material. Fluffy carbon black (or any filler type) can be densified by a conventional pelletizing process, e.g., by combining the silica and/or Silicon-treated carbon black with a liquid such as adding water and feeding the mixture to a pin pelletizer. The pelletizing process can be performed as a batch or continuous process. As an option, the filler coating agent or silica coating agent (e.g., polyethylene glycol) can be combined with the carbon black and/or silica and/or Silicon-treated carbon black prior to pelletizing. Pin pelletizers are well known in the art and include the pin pelletizer described in U.S. Pat. No. 3,528,785. The resulting wet pellets are then heated under controlled temperature and time parameters to remove liquid from the pellets before further handling and shipping. In an alternative process, carbon black or silica pellets can be manufactured by a process that omits a drying step. In such a process, pelletized carbon black or silica contains process water of at least 20% by weight based on a total weight of wet filler, e.g., at least 30% by weight, or at least 40% by weight.

[0066] Alternatively, carbon black and/or silica and/or Silicon-treated carbon black pellets that have been dried (such as commercially available silica pellets) can be rewetted in a pelletizer. The pellets can be granulated, ground, classified, and/or milled, e.g., in a jet mill. The resulting filler can be in fluffy or otherwise particulate form can be repelletized in a pelletizer or otherwise compressed or agglomerated in the presence of water to wet the filler. As an option, the filler can be repelletized in the pelletizer in the presence of the filler coating agent (e.g., polyethylene glycol). Alternatively, the filler can be compressed into other forms, e.g., in a brick form, with equipment known in the art. As another option, carbon black and/or silica and/or Silicon-treated carbon black, such as pellets or particles can be wetted, e.g., by using a fluidized bed, sprayer, mixer, or rotating drum, and the like. Where the liquid is water, never-dried silica or silica that has been rewetted can achieve a water content ranging from 20% to 80%, from 30% to 70% by weight or other ranges, e.g., from 55% to 60% by weight, with respect to the total weight of the wet filler. Wet pellets can be made using methods above and other granulating methods. Co-pellets of carbon black and/or silica and/or Silicon-treated carbon black, and optionally at least one additional filler additional filler, can be made by metering the filler pellets or particulate filler with granules (e.g., two or more of carbon black pellets, fluffy carbon black, Silicon-treated carbon black granules/pearls, silica granules/pearls, fluffy (milled) silica, and/or milled Silicon-treated carbon black) . In any of the steps above, a filler coating agent (e.g., silica coating agent) can be added to make wet co-pellets. Additionally, granules can also be made from wet cake from carbon black and/or silica and/or Silicon-treated carbon black manufacturing processes, and optional addition of filler coating agents can be incorporated. The granules can be dried or kept as wet granules.

[0067] There is no limitation with respect to the type of filler, e.g., at least one of carbon black and/or silica and/ Silicon-treated carbon black and optionally at least one additional filler (e.g., carbon black) that can be used.

[0068] The carbon black can be a furnace black, a gas black, a thermal black, an acetylene black, or a lamp black, a plasma black, a recovered carbon black (e.g., as defined in ASTM D8178-19), or a carbon product containing silicon-containing species, and/or metal containing species and the like. The carbon black can be any grade of reinforcing carbon blacks and semi-reinforcing carbon blacks or other carbon blacks having statistical thickness surface area (STSA) such as ranging from 20 m²/g to 250 m²/g or higher. STSA (statistical thickness surface area) is determined based on ASTM Test Procedure D-5816 (measured by nitrogen adsorption). Examples of ASTM grade reinforcing grades are N110, N121, N134, N220, N231, N234, N299, N326, N330, N339, N347, N351, N358, and N375 carbon blacks. Examples of ASTM grade semi-reinforcing grades are N539, N550, N650, N660, N683, N762, N765, N774, N787, N990 carbon blacks and/or N990 grade thermal blacks.

[0069] As stated, the carbon black can be a rubber black, and especially a reinforcing grade of carbon black or a semi-reinforcing grade of carbon black. Carbon blacks sold under the Regal®, Black Pearls®, Spheron®, Sterling®, Propel®, Endure®, and Vulcan® trademarks available from Cabot Corporation, the Raven®, Statex®, Furnex®, and Neotex® trademarks and the CD and HV lines available from Birla Carbon (formerly available from Columbian Chemicals), and the Corax®, Durax®, Ecorax®, and Purex® trademarks and the CK line available from Orion Engineered Carbons (formerly Evonik and Degussa Industries), and other fillers suitable for use in rubber or tire applications, may also be exploited for use with various implementations. Suitable chemically functionalized carbon blacks include those disclosed in WO 96/18688 and US2013/0165560, the disclosures of which are hereby incorporated by reference. Mixtures of any of these carbon blacks may be employed.

[0070] Other carbon blacks can be used, such as those described in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0071] With regard to the silica filler, one or more types of silica, or any combination of silica(s), can be used in any embodiment disclosed herein. The silica can include or be precipitated silica, fumed silica, silica gel, and/or colloidal silica. The silica can be or include untreated silica. The silica can be suitable for reinforcing elastomer composites and can be characterized by a Brunaur Emmett Teller surface area (BET, as determined by multipoint BET nitrogen adsorption, ASTM D1993) of about 20 m²/g to about 450 m²/g; about 30 m²/g to about 450 m²/g; about 30 m²/g to about 400 m²/g; or about 60 m²/g to about 250 m²/g, from about 60 m²/g to about 250 m²/g, from about 80 m²/g to about 200 m²/g. The silica can have an STSA ranging from about 80 m²/g to 250 m²/g, such as from about 80 m²/g to 200 m²/g or from 90 m²/g to 200 m²/g, from 80 m²/g to 175 m²/g, or from 80 m²/g to 150 m²/g. Highly dispersible precipitated silica can be used as the filler in the present methods. Highly dispersible precipitated silica ("HDS") is understood to mean any silica having a substantial ability to dis-agglomerate and disperse in an elastomeric matrix. Such dispersion determinations may be observed in known manner by electron or optical microscopy on thin sections of elastomer composite. Examples of commercial grades of HDS include, Perkasil® GT 3000GRAN silica from WR Grace & Co, Ultrasil® 7000 silica from Evonik Industries, Zeosil® 1165 MP, 1115 MP, Premium, and 1200 MP silica from Solvay S.A., Hi-Sil® EZ 160G silica from PPG Industries, Inc., and Zeopol® 8741 or 8745 silica from Evonik Industries. Conventional non-HDS precipitated silica may be used as well. Examples of commercial grades of conventional precipitated silica include, Perkasil® KS 408 silica from WR Grace & Co, Zeosil® 175GR silica from Solvay S.A., Ultrasil® VN3 silica from Evonik Industries, and Hi-Sil® 243 silica from PPG Industries, Inc.

[0072] With regard to the Silicon-treated carbon black, one or more types of Silicon-treated carbon black, or any combination of Silicon-treated carbon black(s), can be used in any embodiment disclosed herein. Silicon-treated carbon black is a multi-phase aggregate comprising at least one carbon phase and at least one metal-containing species phase or silicon-containing species phase. In Silicon-treated carbon black, a silicon containing species, such as an oxide or carbide of silicon, is distributed through at least a portion of the carbon black aggregate as an intrinsic part of the carbon black. Silicon-treated carbon blacks are not carbon black aggregates which have been coated or otherwise modified, but actually represent dual-phase aggregate particles. One phase is carbon, which will still be present as graphitic crystallite and/or amorphous carbon, while the second phase is silica, and possibly other silicon-containing species). Thus, the silicon-containing species phase of the silicon treated carbon black is an intrinsic part of the aggregate, distributed throughout at least a portion of the aggregate. Ecoblack™ Silicon-treated carbon blacks are available from Cabot Corporation. The manufacture and properties of these Silicon-treated carbon blacks are described in U.S. Pat. No. 6,028,137, the disclosure of which is incorporated by reference herein.

[0073] The Silicon-treated carbon black can include silicon-containing regions primarily at the aggregate surface of the carbon black, but still be part of the carbon black and/or the Silicon-treated carbon black can include silicon-containing regions distributed throughout the carbon black aggregate. The Silicon-treated carbon black can be oxidized. The Silicon-treated carbon black can contain from about 0.1% to about 50% silicon by weight, e.g., from about 0.1% to about 46.6%, from about 0.1% to about 46%, from about 0.1% to about 45%, from about 0.1% to about 40%, from about 0.1% to about 35%, from about 0.1% to about 30%, from about 0.1% to about 25%, from about 0.1% to about 20%, from about 0.1% to about 15%, from about 0.1% to about 10%, from about 0.1% to about 5%, or from about 0.1% to about 2% by weight, based on the weight of the Silicon-treated carbon black. These amounts can be from about 0.5 wt.% to about 25 wt.%, from about 1 wt.% to about 15 wt.% silicon, from about 2 wt.% to about 10 wt.%, from about 3 wt.% to about 8 wt.%, from about 4 wt.% to about 5 wt.% or to about 6 wt.%, all based on the weight of the Silicon-treated carbon black.

[0074] One of skill in the art will recognize that, separately from the silicon content of the Silicon-treated carbon black, the surface of the particle may also have varying amounts of silica and carbon black. For example, the surface area of the Silicon-treated carbon black may include from about 5% to about 95% silica, for example, from about 10% to about 90%, from about 15% to about 80%, from about 20% to about 70%, from about 25% to about 60%, from about 30% to about 50%, or from about 35% to about 40%, for example, up to about 20% or up to about 30% silica. The area covered by silica at the surface may be determined by the difference between the surface areas of the particles as measured by iodine number (ASTM D- 1510) and nitrogen adsorption (i.e., BET, ASTM D6556).

Solid Elastomer

[0075] With regard to the solid elastomer that is used and mixed with the wet filler, the solid elastomer can be considered a dry elastomer or substantially dry elastomer. The solid elastomer can have a liquid content (e.g., solvent or water content) of 5 wt.% or less, based on the total weight of the solid elastomer, such as 4 wt.% or less, 3 wt.% or less, 2 wt.% or less, 1 wt.% or less, or from 0.1 wt.% to 5 wt.%, 0.5 wt.% to 5 wt.%, 1 wt.% to 5 wt.%, 0.5 wt.% to 4 wt.%, and the like. The solid elastomer (e.g., the starting solid elastomer) can be entirely elastomer (with the starting liquid, e.g., water, content of 5 wt.% or less) or can be an elastomer that also includes one or more fillers and/or other components. For instance, the solid elastomer can be from 50 wt.% to 99.9 wt.% elastomer with 0.1 wt.% to 50 wt.% filler predispersed in the elastomer in which the predispersed filler is in addition to the wet filler. Such elastomers can be prepared by dry mixing processes between non-wetted filler and solid elastomers. Alternatively, a composite made by mixing a wet filler and solid elastomer (e.g., according to the processes disclosed herein) can be used as the solid elastomer and further mixed with a wet filler according to the processes disclosed herein. However, the solid elastomer is not a composite, mixture or compound made by a liquid masterbatch process and is not any other pre-blended composite of filler dispersed in an elastomer while the elastomer is in a liquid state, e.g., a latex, suspension or solution.

[0076] Any solid elastomer can be used in the present methods. Exemplary elastomers include natural rubber (NR), synthetic elastomers such as styrene butadiene rubbers (SBR, such as solution SBR (SSBR), emulsion SBR (ESBR), or oil-extended SSBR (OESSBR)), polybutadiene (BR), polyisoprene rubbers (IR), functionalized SBR, functionalized BR, functionalized NR, ethylene-propylene rubber (e.g., EPDM), isobutylene-based elastomers (e.g., butyl rubber), halogenated butyl rubber, polychloroprene rubber (CR), nitrile rubbers (NBR), hydrogenated nitrile rubbers (HNBR), fluoroelastomers, perfluoroelastomers, and silicone rubber, e.g., natural rubber, functionalized natural rubber, styrene-butadiene rubber, functionalized styrene-butadiene rubber, polybutadiene rubber, functionalized polybutadiene rubber, polyisoprene rubber, ethylene-propylene rubber, nitrile rubber, hydrogenated nitrile rubber, and blends thereof, or e.g., natural rubber, styrene-butadiene rubber, polybutadiene rubber, and blends thereof, e.g., a blend of first and second solid elastomers. Other synthetic polymers that can be used in the present methods (whether alone or as blends) include hydrogenated SBR, and thermoplastic block copolymers (e.g., such as those that are recyclable). Synthetic polymers include copolymers of ethylene, propylene, styrene, butadiene and isoprene. Other synthetic elastomers include those synthesized with metallocene chemistry in which the metal is selected from Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Tm, Yb, Lu, Co, Ni, and Ti. Polymers made from bio-based monomers can also be used, such as monomers containing modern carbon as defined by ASTM D6866, e.g., polymers made from bio-based styrene monomers disclosed in U.S. Pat. No. 9,868,853, the disclosure of which is incorporated by reference herein, or polymers made from bio-based monomers such as butadiene, isoprene, ethylene, propylene, farnesene, and comonomers thereof. If two or more elastomers are used, the two or more elastomers can be charged into the mixer as a blend at the same time (as one charge or two or more charges) or the elastomers can be added separately in any sequence and amount. For example, the solid elastomer can comprise natural rubber blended with one or more of the elastomers disclosed herein, e.g., butadiene rubber and/or styrene-butadiene rubber, or SBR blended with BR, etc. For instance, the additional solid elastomer can be added separately to the mixer and the natural rubber can be added separately to the mixer.

[0077] The solid elastomer can be or include natural rubber. If the solid elastomer is a blend, it can include at least 50 wt.% or at least 70 wt.% or at least 90 wt.% natural rubber. The blend can further comprise synthetic elastomers such as one or more of styrene-butadiene rubber, functionalized styrene-butadiene rubber, and polybutadiene rubber, and/or any other elastomers disclosed herein.

[0078] The natural rubber may also be chemically modified in some manner. For example, it may be treated to chemically or enzymatically modify or reduce various nonrubber components, or the rubber molecules themselves may be modified with various monomers or other chemical groups such as chlorine. Other examples include epoxidized natural rubber and natural rubber having a nitrogen content of at most 0.3 wt.%, as described in PCT Publ. No. WO 2017/207912.

[0079] Other exemplary elastomers include, but are not limited to, rubbers, polymers (e.g., homopolymers, copolymers and/or terpolymers) of 1,3-butadiene, styrene, isoprene, isobutylene, 2,3-dialkyl-l,3-butadiene, where alkyl may be methyl, ethyl, propyl, etc., acrylonitrile, ethylene, propylene and the like.

[0080] Other applicable solid elastomers that can be used in the presently disclosed methods are disclosed in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

Mixing Methods

[0081] With regard to the mixer that can be used in any of the methods disclosed herein, any suitable mixer can be utilized that is capable of combining (e.g., mixing together or compounding together) a filler with solid elastomer. The mixer(s) can be a batch mixer or a continuous mixer. A combination of mixers and processes can be utilized in any of the methods disclosed herein, and the mixers can be used sequentially, in tandem, and/or integrated with other processing equipment. The mixer can be an internal or closed mixer or an open mixer, or an extruder or a continuous compounder or a kneading mixer or a combination thereof. The mixer can be capable of incorporating filler into solid elastomer and/or capable of dispersing the filler in the elastomer and/or distributing the filler in the elastomer.

[0082] The mixer can have one or more rotors (at least one rotor). The at least one rotor or the one or more rotors can be screw-type rotors, intermeshing rotors, tangential rotors, kneading rotor(s), rotors used for extruders, a roll mill that imparts significant total specific energy, or a creper mill. Generally, one or more rotors are utilized in the mixer, for example, the mixer can incorporate one rotor (e.g., a screw type rotor), two, four, six, eight, or more rotors. Sets of rotors can be positioned in parallel and/or in sequential orientation within a given mixer configuration.

[0083] With regard to mixing, the mixing can be performed in one or more mixing steps. Mixing commences when at least the solid elastomer and wet filler (and optionally silica coating agent or filler coating agent) are charged to the mixer and energy is applied to a mixing system that drives one or more rotors of the mixer. The one or more mixing steps can occur after the charging step is completed or can overlap with the charging step for any length of time. For example, a portion of one or more of the solid elastomers and/or wet filler can be charged into the mixer before or after mixing commences. The mixer can then be charged with one or more additional portions of the solid elastomer and/or filler and/or filler coating agent. For batch mixing, the charging step is completed before the mixing step is completed.

[0084] In the methods disclosed herein, at least the solid elastomer, wet filler, and optionally the filler (e.g., silica) coating agent (e.g., polyethylene glycol) are charged (e.g. fed, introduced) into the mixer. The charging of the solid elastomer, the filler, and optionally the filler coating agent (e.g., the silica coating agent) can occur in one or multiple steps or additions. The charging can occur in any fashion including, but not limited to, conveying, metering, dumping and/or feeding in a batch, semi-continuous, or continuous flow of the solid elastomer and the wet filler into the mixer. The solid elastomer and fillers are not introduced as a pre-mixture to the mixer, in which the pre-mixture was prepared by means other than combining solid elastomer and the filler. The solid elastomer and filler can be added together but not as a mixture prepared by means other than combining solid elastomer and filler (e.g., not where the filler is pre-dispersed into the elastomer by means other than combining solid elastomer and filler, in which the elastomer is the continuous phase). A mixture or pre-mixture or pre-blend from solid elastomer and wet filler, and optionally the filler coating agent can be charged to the mixer and can be prepared by any number of known methods, e.g., in a mixer or a container.

[0085] The charging of the solid elastomer, the wet filler, and optionally the filler coating agent (e.g., silica coating agent) can occur all at once (e.g., any of the mixtures or copellets), or sequentially, and can occur in any sequence. The charging can comprise separate charges of the wet filler and optionally the filler coating agent (e.g., silica coating agent). For example, (a) all solid elastomer added first, (b) all filler added first, (c) all solid elastomer added first with a portion of wet filler followed by the addition of one or more remaining portions of wet filler and optionally the filler coating agent (whether alone or in mixtures or as co-pellets as described herein), (d) a portion of solid elastomer added and then a portion of wet filler and optionally the filler coating agent added, (e) at least a portion of the wet filler is added first followed by at least a portion of the solid elastomer and/or at least a portion of the filler coating agent, (f) at the same time or about the same time, a portion of solid elastomer, a portion of the wet filler, and a portion of the filler coating agent are added as separate charges to the mixer, or (g) at least a portion of solid elastomer and at least a portion or all of the filler (wet silica and/or wet Silicon-treated carbon black and at least one additional filler, wet or non-wetted) is added in any order and in one or more portions, mixing the at least a portion of solid elastomer and at least a portion or all of the filler, charging the mixer with at least a portion of the filler coating agent, and mixing the solid elastomer, filler, and filler coating agent to form the mixture. As yet another alternative the wet filler and the filler coating agent can be charged as a mixture, e.g., a particulate mixture or as a co-pellet as described herein. Other applicable methods of charging the mixer with the solid elastomer and wet filler are disclosed in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0086] As an option, control over mixer surface temperatures, by whichever mechanism(s), can provide an opportunity for longer mixing or residence times, which can result in improved filler dispersion and/or improved rubber-filler interactions and/or consistent mixing and/or efficient mixing, compared to mixing processes without temperature control of at least one mixer surface.

[0087] The temperature-control means can be, but is not limited to, the flow or circulation of a heat transfer fluid through channels in one or more parts of the mixer. For example, the heat transfer fluid can be water or heat transfer oil. For example, the heat transfer fluid can flow through the rotors, the mixing chamber walls, the ram, and the drop door. In other embodiments, the heat transfer fluid can flow in a jacket (e.g., a jacket having fluid flow means) or coils around one or more parts of the mixer. As another option, the temperature control means (e.g., supplying heat) can be electrical elements embedded in the mixer. The system to provide temperature-control means can further include means to measure either the temperature of the heat transfer fluid or the temperature of one or more parts of the mixer. The temperature measurements can be fed to systems used to control the heating and cooling of the heat transfer fluid. For example, the desired temperature of at least one surface of the mixer can be controlled by setting the temperature of the heat transfer fluid located within channels adjacent one or more parts of the mixer, e.g., walls, doors, rotors, etc.

[0088] The temperature of the at least one temperature-control means can be set and maintained, as an example, by one or more temperature control units ("TCU"). This set temperature, or TCU temperature, is also referred to herein as "T_z." In the case of temperature-control means incorporating heat transfer fluids, T_z is an indication of the temperature of the fluid itself.

[0089] As an option, the temperature-control means can be set to a temperature, T_z, ranging from 30°C to 150°C, from 40°C to 150°C, from 50°C to 150°C, or from 60°C to 150°C, e.g., from 30°C to 155°C, from 30°C to 125°C, from 40°C to 125°C, from 50°C to 125°C, from 60°C to 125°C, from 30°C to 110°C, from 40°C to 110°C, from 50°C to 110°C, 60°C to 110°C, from 30°C to 100°C, from 40°C to 100°C, from 50°C to 100°C, 60°C to 100°C, from 30°C to 95°C, from 40°C to 95°C, from 50°C to 95°C, 50°C to 95°C, from 30°C to 90°C, from 40°C to 90°C, from 50°C to 90°C, from 65°C to 95°C, from 60°C to 90°C, from 70°C to 110°C, from 70°C to 100°C, from 70°C to 95°C, 70°C to 90°C, from 75°C to 110°C, from 75°C to 100°C, from 75°C to 95°C, or from 75°C to 90°C. Other ranges are possible with equipment available in the art.

[0090] Compared to dry mixing, under similar situations of filler type, elastomer type, and mixer type, the present processes can allow higher energy input. Controlled removal of the water from the mixture enables longer mixing times and consequently improves the dispersion of the filler. As described herein, the present process provides operating conditions that balance longer mixing times with evaporation or removal of water in a reasonable amount of time.

[0091] Other operating parameters to be considered include the maximum pressure that can be used. Pressure affects the temperature of the filler and rubber mixture. If the mixer is a batch mixer with a ram, the pressure inside the mixer chamber can be influenced by controlling the pressure applied to the ram cylinder.

[0092] As another option, rotor tip speeds can be optimized. The energy inputted into the mixing system is a function, at least in part, of the speed of the at least one rotor and rotor type. Tip speed, which takes into account rotor diameter and rotor speed, can be calculated according to the formula:

Tip speed, m/s = n x (rotor diameter, m) x (rotational speed, rpm) / 60.

[0093] As tip speeds can vary over the course of the mixing, as an option, the tip speed of at least 0.5 m/s or at least 0.6 m/s is achieved for at least 50% of the mixing time, e.g., at least 60%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90%, at least 95%, or substantially all of the mixing time. The tip speed can be at least 0.6 m/s, at least 0.7 m/s, at least 0.8 m/s, at least 0.9 m/s, at least 1.0 m/s, at least 1.1 m/s, at least 1.2 m/s, at least 1.5 m/s or at least 2 m/s for at least 50% of the mixing time, or other portions of the mixing listed above. The tip speeds can be selected to minimize the mixing time, or can be from 0.6 m/s to 10 m/s, from 0.6 m/s to 8 m/s, from 0.6 to 6 m/s, from 0.6 m/s to 4 m/s, from 0.6 m/s to 3 m/s, from 0.6 m/s to 2 m/s, from 0.7 m/s to 4 m/s, from 0.7 m/s to 3 m/s, from 0.7 m/s to 2 m/s, from 0.7 m/s to 10 m/s, from 0.7 m/s to 8 m/s, from 0.7 to 6 m/s, from 1 m/s to 10 m/s, from 1 m/s to 8 m/s, from 1 m/s to 6 m/s, from 1 m/s to 4 m/s, from 1 m/s to 3 m/s, or from 1 m/s to 2 m/s, (e.g., for at least 50% of the mixing time or other mixing times described herein).

[0094] Any one or combination of commercial mixers with one or more rotors, temperature control means, and other components, and associated mixing methods to produce rubber compounds can be used in the present methods, such as those disclosed in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0095] By "one or more mixing steps," it is understood that the steps disclosed herein may be a first mixing step followed by further mixing steps prior to discharging. The one or more mixing steps can be a single mixing step, e.g., a one-stage or single stage mixing step or process, in which the mixing is performed under one or more of the following conditions: at least one of the mixer temperatures are controlled by temperature controlled means with one or more rotors operating at a tip speed of at least 0.6 m/s for at least 50% of mixing time, and/or the at least one temperature-control means that is set to a temperature, T_z, of 65°C or higher, and/or continuous mixing; each is described in further detail herein. In certain instances, in a single stage or single mixing step the composite can be discharged with a liquid content of no more than 10% by weight. In other embodiments, two or more mixing steps or mixing stages can be performed so long as one of the mixing steps is performed under one or more of the stated conditions.

[0096] As indicated, during the one or more mixing steps, in any of the methods disclosed herein, at least some liquid present in the mixture and/or wet filler introduced is removed at least in part by evaporation. As an option, the one or more mixing steps or stages can further remove a portion of the liquid from the mixture by expression, compaction, and/or wringing, or any combinations thereof. Alternatively, a portion of the liquid can be drained from the mixer after or while the composite is discharged.

[0097] During the mixing cycle, after much of the liquid has been released from the composite and the filler incorporated, the mixture experiences an increase in temperature. It is desired to avoid excessive temperature increases that would degrade the elastomer. Discharging, (e.g., "dumping" in batch mixing), can occur on the basis of time or temperature or specific energy or power parameters selected to minimize such degradation.

[0098] In any methods disclosed herein, the discharging step from the mixer occurs and results in a composite comprising the filler dispersed in the natural rubber at a total loading of at least 20 phr, e.g., from 20 to 250 phr, or other loadings disclosed herein. As an option, discharging occurs on the basis of a defined mixing time. The mixing time between the start of the mixing and discharging can be about 1 minute or more, such as from about 1 minute to 40 minutes, from about 1 minute to 30 minutes, from about 1 minute to 20 minutes, or from 1 minute to 15 minutes, or from 3 minutes to 30 minutes, from 5 minutes to 30 minutes, or from 5 minutes to 20 minutes, or from 5 minutes to 15 minutes, or from 1 minute to 12 minutes, or from 1 minute to 10 minutes or other times. Alternatively, for batch internal mixers, ram down time can be used as a parameter to monitor batch mixing times, e.g., the time that the mixer is operated with the ram in its lowermost position e.g., fully seated position or with ram deflection (as described in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein). Ram down time can be less than 30 min., less than 15 min., less than 10 min., or ranges from 3 min. to 30 min or from 5 min. to 15 min, or from 5 min. to 10 min. As an option, discharging occurs on the basis of dump or discharge temperature. For example, the mixer can have a dump temperature ranging from 120°C to 190°C, 130°C to 180°C, such as from 140°C to 180°C, from 150°C to 180°C, from 130°C to 170°C, from 140°C to 170°C, from 150°C to 170°C, or other temperatures within or outside of these ranges.

[0099] The methods further include discharging from the mixer the composite that is formed. The discharged composite can have a liquid content of no more than 10% by weight based on the total weight of the composite, as outlined in the following equation:

Liquid content of composite % = 100*[mass of liquid] / [mass of liquid + mass of dry composite]

[0100] In any of the methods disclosed herein, the discharged composite can have a liquid content of no more than 10% by weight, no more than 5%, no more than 2%, or no more than 1%, based on the total weight of the composite. This amount can range from 0.1% to 10%, from 0.1% to 5%, from 0.1% to 3%, from 0.1% to 2%, from 0.5% to 5%, or from 0.5% to 5%, based on the total weight of the composite discharged from the mixer at the end of the process. In any of the methods disclosed herein, the liquid content (e.g., "moisture content") can be the measured weight % of liquid present in the composite based on the total weight of the composite.

[0101] In any of the methods disclosed herein, liquid content in the composite can be the measured as weight % of liquid present in the composite based on the total weight of the composite. Any number of instruments are known in the art for measuring liquid (e.g., water) content in rubber materials, such as a coulometric Karl Fischer titration system, or a moisture balance, e.g., from Mettler (Toledo International, Inc., Columbus, OH).

[0102] In any of the methods disclosed herein, while the discharged composite can have a liquid content of 10% by weight or less, there optionally may be liquid (e.g., water) present in the mixer which is not held in the composite that is discharged. This excess water is not part of the composite and is not part of any water content calculated for the composite.

[0103] In any of the methods disclosed herein, the total water liquid of the material charged into the mixer is higher than the water content of the composite discharged at the end of the process. For instance, the water content of the composite discharged can be lower than the liquid content of the material charged into the mixer by an amount of from 10% to 99.9% (wt% vs wt%), from 10% to 95%, or from 10% to 50%. [0104] Optionally the process further comprises adding the filler coating agent (e.g., silica coating agent) and/or anti-degradant during the charging or the mixing, i.e., during the one or more mixing steps. In any embodiment disclosed herein, as another option, after the mixing of at least the solid elastomer and wet filler has commenced and prior to the discharging step, the method can further include adding the filler coating agent and optionally at least one anti-degradant to the mixer so that the filler coating agent (e.g., silica coating agent) and the at least one anti-degradant is mixed in with the solid elastomer and fillers. As an option, the mixture consists essentially of the solid elastomer and the wet filler; the mixture consists essentially of the solid elastomer, the wet filler, and the antidegradant; the composite consists essentially of the filler dispersed in the elastomer and the antidegradant; the composite consists of the filler dispersed in the elastomer; the composite consists of the filler dispersed in the elastomer and the antidegradant. As another option, the adding of the filler coating agent (e.g., silica coating agent) and anti- degradant(s) can occur prior to the composite being formed and having a water content of 10 wt.% or less, or 5 wt.% or less.

[0105] The optional adding of the filler coating agent (e.g., silica coating agent) and/or the anti-degradant(s) can occur at any time prior to the discharging step, e.g., before or after the mixer reaches an indicated mixer temperature of 120°C or higher. This indicated mixer temperature can be measured by a temperature-measuring device within the mixing cavity. The indicated temperature of the mixer can be the same as or differ by 30°C or less, or 20°C or less, or 10°C or less (or 5°C or less or 3°C or less or 2°C or less) from the maximum temperature of the mixture or the composite achieved during the mixing stage (which can be determined by removing the composite from the mixer and inserting a thermocouple or other temperature measuring device into the composite). In this mixing method, as an option, the filler coating agent (e.g., silica coating agent) and/or the antidegradant can be added to the mixer when the mixer reaches the temperature of 120°C or higher. In other embodiments, the indicated mixer temperature can range from 120°C to 190°C, from 125°C to 190°C, from 130°C to 190°C, from 135°C to 190°C, from 140°C to

190°C, from 145°C to 190°C, from 150°C to 190°C, from 120°C to 180°C, from 125°C to

180°C, from 130°C to 180°C, from 135°C to 180°C, from 140°C to 180°C, from 145°C to

180°C, from 150°C to 180°C, from 120°C to 170°C, from 125°C to 170°C, from 130°C to 170°C, from 135°C to 170°C, from 140°C to 170°C, from 145°C to 170°C, from 150°C to 170°C, and the like.

[0106] Examples of an anti-degradant that can be introduced is N-(l,3- dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), and others are described in other sections herein. The anti-degradant can be introduced in an amount ranging from 1% to 5%, from 0.5% to 2%, or from 0% to 3% based on the weight of the composite that is formed. Anti-degradants added during the charging step or the mixing step may help prevent elastomer degradation during the mixing; however, due to the presence of the water in the mixture, the rate of degradation of the elastomer is lower compared to dry mix processes and the addition of anti-degradant can be delayed.

[0107] After the composite is formed and discharged, the method can include the further optional step of mixing the composite with additional elastomer to form a composite comprising a blend of elastomers. The "additional elastomer" or second elastomer can be additional natural rubber or can be an elastomer that is not natural rubber such as any elastomer disclosed herein, e.g., synthetic elastomers (e.g. styrene butadiene rubbers (SBR, e.g., SSBR or ESBR), polybutadiene (BR) and polyisoprene rubbers (IR), ethylene-propylene rubber (e.g., EPDM), isobutylene-based elastomers (e.g., butyl rubber), polychloroprene rubber (CR), nitrile rubbers (NBR), hydrogenated nitrile rubbers (HNBR), polysulfide rubbers, polyacrylate elastomers, fluoroelastomers, perfluoroelastomers, and silicone elastomers). Blends of two or more types of elastomers (blends of first and second elastomers), including blends of synthetic and natural rubbers or with two or more types of synthetic or natural rubber, may be used as well.

[0108] In addition to the solid elastomer, filler, and filler coating agent (e.g., silica coating agent), the mixer can be charged with one or more charges of at least one additional elastomer to form a composite blend. The composite discharged (e.g., after single-stage or two or multi-stage mixing) can have a moisture content of no greater than 5%, 3%, 2% by weight relative to the weight of the composite when blending with one or more additional elastomers (e.g., a composite comprising carbon black and natural rubber can be blended with synthetic elastomers such as BR or SBR). Further, both elastomers and fillers (wet or dry, such as wet or dry carbon black and/or silica and/or Silicon-treated carbon black) can be combined with the composite. As another option, the process can comprise mixing the discharged composite with additional elastomer to form the blend. The at least one additional elastomer can be the same as the solid elastomer or different from the solid elastomer.

[0109] As another option, a composite comprising a filler (e.g., carbon black and/or silica and/or Silicon-treated carbon black) and an elastomer (e.g., natural rubber and/or SBR and/or BR) prepared according to the presently disclosed methods can be combined with a masterbatch containing natural rubber and/or synthetic polymers made by any method known in the art, such as by known dry mixing or solvent masterbatch processes. For example, silica/elastomer masterbatches can be prepared as described in U.S. Pat. No. 9,758,627 and 10,125,229, or masterbatches from neodymium-catalyzed polybutadienes as described in U.S. Pat. No. 9,758,646, the disclosures of which are incorporated by reference herein. The masterbatch can have a fibrous filler, such as poly(p- phenylene terephthalamide) pulp, as described in U.S. Pat. No. 6,068,922, the disclosure of which is incorporated by reference herein. Masterbatches can have fillers such as graphenes, graphene oxides, reduced graphene oxides, or densified reduced graphene oxide granules, carbon nanotubes, single-wall carbon nanotubes, multi-wall carbon nanotubes, and carbon nanostructures, in which masterbatches of the latter are disclosed in U.S. Pat. No. 9,447,259, and PCT Appl. No. PCT/US2021/027814, the disclosures of which are incorporated by reference herein. Other suitable masterbatches can include the composites prepared from mixing wet filler and solid elastomer, as described in PCT Publ. No. WO 2020/247663, the disclosures of which is incorporated by reference herein. For example, the masterbatch can have a filler such as carbon black and/or silica and an elastomer such as natural rubber and/or SBR and/or butadiene rubber. Commercially available masterbatches can also be used, e.g., commercially available masterbatches such as Emulsil™ silica/SBR masterbatch or Emulblack™ carbon black/SBR masterbatch (both available from Dynasol group).

[0110] Exemplary masterbatches comprising elastomer blends (whether the blend is formed from first or single stage mixing or formed from multi-stage mixing), include: blends of natural rubber with synthetic, bio-sourced, and/or functionalized elastomers (e.g., SSBR, ESBR, BR) where the filler can be selected from one or more of carbon black, silica, and Silicon-treated carbon black. [0111] Any of the methods disclosed herein relates, in part, to methods of preparing a composite that involves at least two mixing steps or stages. These two (or more) mixing steps can be considered multi-step or multi-stage mixing with a first mixing step or stage and at least a second mixing step or stage. One or more of the multi-stage mixing processes can be batch, continuous, semi-continuous, and combinations thereof.

[0112] For multi-stage process, the methods for preparing the composite include the step of charging or introducing into a first mixer at least a) one or more solid elastomers, b) one or more fillers wherein at least one filler or a portion of at least one filler is wet filler (e.g., wet silica and/or wet Silicon-treated carbon black) as described herein (e.g. a wet filler that comprises a filler and a liquid present in an amount of at least 15% by weight, and optionally, c) the filler coating agent. The combining of the solid elastomer with wet filler and optionally the filler coating agent forms a mixture or composite during this mixing step(s), which can be considered as a first mixing step or stage. The method further includes mixing the mixture, in this first mixing step, to an extent that at least a portion of the liquid is removed by evaporation or an evaporation process that occurs during the mixing. This first mixing step (in one or more mixing steps) or stage is conducted using one or more of the processes described earlier that forms a composite with the understanding that, after completion of the first mixing, it is not necessary for the mixture discharged from the mixer after the first mixing step (e.g., a discharged mixture) to have a liquid content of no more than 10 wt.%. In other words, with the multi-stage process(es), the mixture resulting from the completion of the first mixing from the first mixer (or first mixing step) can have a liquid content above 10 wt.%, but does have a liquid content that is reduced (by wt.%) as compared to the liquid content of the combined solid elastomer and wet filler at the start of the first mixing step.

[0113] For multi-stage mixing processes, the mixture that is discharged from the first mixer has a liquid content that is reduced to an amount less than the liquid content at the beginning of step (b), e.g., the liquid present in the wet filler, e.g., reduced by 50 wt.%, by 60 wt.%, by 70 wt.%, or more. As an option, the discharged mixture can have a liquid content (depending, in part, on the liquid content of the wet filler) ranging from 0.5% to 20% by weight relative to the weight of the mixture, e.g., from 0.5% to 17%, from 0.5% to 15%, from 0.5% to 12%, from 0.5% to 10%, from 0.5% to 7%, from 0.5% to 5%, from 0.5% to 3%, from 0.5% to 2%, from 1% to 20%, from 1% to 17%, from 1% to 15%, from 1% to 12%, from 1% to 10%, from 1% to 7%, from 1% to 5%, from 1% to 3%, from 1% to 2%, from 2% to 20%, from 2% to 17%, from 2% to 15%, from 2% to 12%, from 2% to 10%, from 2% to 7%, from 2% to 5%, from 2% to 3%, from 3% to 20%, from 3% to 17%, from 3% to 15%, from 3% to 12%, from 3% to 10%, from 3% to 7%, from 3% to 5%, from 5% to 20%, from 5% to 17%, from 5% to 15%, from 5% to 12%, from 5% to 10%, or from 5% to 7%.

[0114] As an option, for multi-stage processes, the liquid content of the wet filler (wet silica and/or wet Silicon-treated carbon black) can be at least 20% by weight, at least 25% by weight, at least 30% by weight, at least 35% by weight, at least 40% by weight, at least 45% by weight, at least 50% by weight or from 20% to 99%, from 20% to 95%, from 20% to 90%, from 20% to 80%, from 20% to 70%, from 20% to 60%, from 30% to 99%, from 30% to

95%, from 30% to 90%, from 30% to 80%, from 30% to 70%, from 30% to 60%, from 40 % to

99%, from 40% to 95%, from 40% to 90%, from 40% to 80%, from 40% to 70%, from 40% to

60%, from 45 % to 99%, from 45% to 95%, from 45% to 90%, from 45% to 80%, from 45% to

70%, from 45% to 60%, from 50% to 99%, from 50% to 95%, from 50% to 90%, from 50% to

80%, from 50% to 70%, or from 50% to 60% by weight, relative to the total weight of the wet filler, or any other amounts disclosed herein.

[0115] Before the first mixer or other mixer is used in the second mixing step, as a further option, there can be a standing time wherein the composite formed from the first mixing rests or cools or both in the first mixer or in another container or location (e.g., mixing, stopping, and then mixing further). For instance, this standing time can be such that the mixture obtains a material temperature (also referred to as probe temperature) of less than 180°C before the further mixing step commences (e.g., the discharged mixture can have a material temperature ranging from about 100°C to about 180°C, of from about 70°C to 179°C, or from about 100°C to about 170°C, or from about 120°C to about 160°C). Or, the standing time before the further or second mixing step commences, can be from about 1 minute to 60 minutes or more. The material temperature can be obtained by a number of methods known in the art, e.g., by inserting a thermocouple or other temperature measuring device into the mixture or composite.

[0116] The method then includes mixing or further mixing the mixture in at least a second mixing step or stage utilizing the same mixer (i.e., the first mixer) and/or utilizing a second mixer(s) that is different from the first mixer. With a multi-stage mixing process, there is the option of charging the filler coating agent (e.g., polyethylene glycol) to either the first mixer, the second mixer, or both.

[0117] After the first mixing, the further mixing step(s) conducted for the multistage mixing can utilize any one or more of the mixing procedures or parameters or steps utilized in the first mixing step as described herein. Thus, in conducting the further mixing step or stage, the same or different mixer design and/or same or different operating parameters as for the first mixer can be used in the further mixing stage. The mixers and their options described earlier for the first mixing step and/or the operating parameters described earlier for the mixing step can be optionally used in the further or second mixing step (e.g. the mixing steps, as described herein, that include a tip speed of at least 0.5 m/s for at least 50% of the time or at least 0.6 m/s for at least 50% of the time, and/or a Tz of 65°C or higher, among other parameters disclosed herein or in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0118] In the multi-stage processes, a second mixing step (second stage mix) can also comprise charging the mixer with other components in addition to the mixture discharged from the first mixing step. For example, where the filler coating agent is not charged to the first mixer, the filler coating agent can be charged to the second mixer. Additionally or alternatively, as an example, the method can comprise charging additional filler, such as dry filler, wet filler, or a blend thereof prior to or during the second mixing step. The additional filler can be the same or different from the filler already present in the mixture. For example, the mixture discharged from the first mixer can be considered a masterbatch in which either all or a portion is combined with additional filler. For example, the additional filler can be wet or dry carbon black, silica, Silicon-treated carbon black (and blends thereof) can be added to the mixture discharged from the first mixing step, such as a mixture comprising carbon black and natural rubber.

[0119] For the multi-stage mixing process(es), in at least one option, at least a second mixer is used in the further mixing step(s). When this option is used, the second mixer can have the same or different design as the first mixer, and/or can have the same or one or more different operating parameters as the first mixer. Specific examples, not meant to be limiting, are provided below with respect to first mixer and second mixer options. For instance, the first mixer can be a tangential mixer or an intermesh mixer, and the second mixer can be a tangential mixer, an intermesh mixer, an extruder, a kneader, or a roll mill. For instance, the first mixer can be an internal mixer and the second mixer can be a kneader, a single screw extruder, a twin-screw extruder, a multiple-screw extruder, a continuous compounder, or a roll mill. For instance, the first mixer can be a first tangential mixer, and the second mixer can be a second (different) tangential mixer. For instance, the first mixer is operated with a ram, and the second mixer is operated without a ram. For instance, the second mixer is utilized and is operated at a fill factor of the mixture, on a dry weight basis, ranging from 25% to 70%, from 25% to 60%, from 25% to 50%, from 30% to 50%, or other fill factor amounts described herein.

[0120] As an option, the method includes mixing or further mixing the mixture in at least a second mixing step or stage utilizing the same mixer (i.e., the first mixer) and/or utilizing a second mixer(s) that is different from the first mixer. The mixing with the second mixer can be such that the second mixer or second mixing is operated at a ram pressure of 5 psi or less and/or with the ram raised to at least 75% of the ram's highest level (such as at least 85%, at least 90%, at least 95%, or at least 99% or 100% of the ram's highest level), and/or a ram operated in floating mode, and/or a ram positioned such that it does not substantially contact the mixture; and/or a ram-less mixer; and/or a fill factor of the mixture ranges from 25% to 70%. The method then includes discharging from the last used mixer the composite that is formed such that the composite has a liquid content of no more than 10% by weight based on the total weight of the composite. Methods for operating a second mixer that are suitable are described in PCT Publ. No. WO 2020/247663, the disclosure of which is incorporated by reference herein.

[0121] Compared to dry mixing, under similar situations of filler type, elastomer type, and mixer type, the present processes can allow higher energy input. Controlled removal of the liquid from the wet filler enables longer mixing times and consequently improves the dispersion of the filler. The energy input can be indicated by a resulting total specific energy imparted to the composite during the mixing process. For example, mixing occurs when at least the wet filler and solid elastomer are charged to the mixer and energy is applied to at least one rotor. For example, in a batch mixer, total specific energy takes into account energy applied to the rotor(s) between the charge of solid elastomer and/or wet filler and the discharge per kg of composite on a dry weight basis. For a continuous mixer, total specific energy is the power input per kg of output on a dry weight basis at steady state conditions. For processes that have multiple stage mixing, the total specific energy is the sum of the specific energies from each mixing process. The determination of total specific energy preferably does not include the amount of energy used for shaping or forming the discharged composite (e.g., excludes energy of roll milling of the composite). The resulting "total specific energy," as defined herein is the energy, ER (e.g., electrical energy) applied to a mixing system that drives the one or more rotors per mass of composite on a dry weight basis. This total specific energy can also be designated at ETOTAL. As described herein, the present processes provide a total specific energy under selected operating conditions that balance longer mixing times with evaporation or removal of water in a reasonable amount of time.

[0122] As an option, the process comprises, in at least one of the mixing steps, conducting the mixing such that a resulting total specific energy is at least 1,100 kJ/kg, at least 1,200 kJ/kg, at least 1,300 kJ/kg, or at least 1,400 kJ/kg or at least 1,500 kJ per kg composite, e.g., at least 1,600 kJ/kg, at least 1,700 kJ/kg, at least 1,800 kJ/kg, at least 1,900 kJ/kg, at least 2,000 kJ/kg, at least 2,500 kJ/kg, or at least 3,000 kJ/kg. As an alternative for certain systems, the total specific energy can range from 1,000 kJ/kg to 3,000 kJ/kg, e.g., from 1,000 kJ/ to 2,500 kJ/kg, from 1,100 kJ/ to 2,500 kJ/kg, etc. As an option, the total specific energy can range from about 1,400 kJ/kg composite or about 1,500 kJ/kg composite (or per kg mixture present in the mixer) to about 10,000 kJ/kg composite (or per kg mixture present in the mixer), such as from 2,000 kJ/kg to about 5,000 kJ or 1,500 kJ/kg to 8,000 kJ/kg, 1,500 kJ/kg to 7,000 kJ/kg, 1,500 kJ/kg to 6,000 kJ/kg, 1,500 kJ/kg to 5,000 kJ/kg, 1,500 kJ/kg to 3,000 kJ/kg, 1,600 kJ/kg to 8,000 kJ/kg, 1,600 kJ/kg to 7,000 kJ/kg, 1,600 kJ/kg to 6,000 kJ/kg, 1,600 kJ/kg to 5,000 kJ/kg, 1,600 kJ/kg to 4,000 kJ/kg, 1,600 kJ/kg to 3,000 kJ/kg, or other values in any of these ranges.

[0123] As an option, the method comprises applying an average specific power (specific energy/mix time, kW/kg) during the one or more mixing steps. Average specific power can be reported for a single mixing step such as a first stage mix, in which average specific power for the mixing stage = specific energy/mix time. The mix time can be the ram down time. For continuous mixing, the average specific power can be calculated by the average specific energy divided by the mixer residence time. Alternatively, for continuous mixing, average specific power can be calculated over a defined period of time (kW) divided by the mass of material inside the mixer a certain point in time (kg).

[0124] As an option, the average specific power that is applied is at least 2.5 kW/kg over mixing time, e.g., at least 3 kW/kg, at least 3.5 kW/kg, at least 4 kW/kg, at least 4.5 kW/kg, from 2.5 kW/kg to 10 kW/kg, from 2.5 kW/kg to 9 kW/kg, from 2.5 kW/kg to 8 kW/kg, or from 2.5 kW/kg to 10 kW/kg over ram down time. As an option, one or more parameters can be selected to attain a desired specific power, including but not limited to, liquid content in the filler, Tz, fill factor, and/or tip speed.

[0125] If sufficiently high average specific power is employed during the mixing with wet fillers, the mixing time, e.g., ram down time, can be reduced to an amount that is suitable for both efficiency and product properties. Accordingly, as an option, the method comprises, in at least one or more mixing steps, applying an average specific power of at least 2.5 kW/kg (or other ranges disclosed herein) over ram down time that is 10 minutes or less, e.g., 8 minutes or less, or 6 minutes or less.

[0126] The energy that is applied, for instance imparted by one or more rotors in the mixer, can be constant or relatively constant. As an option, the instantaneous specific energy per unit time (kJ/(min-kg) (specific power) can be within 10% of the mean specific energy per unit time (average specific power) during the mixing process.

[0127] In any method of producing a composite disclosed herein, the method can further include one or more of the following steps, after formation of the composite: one or more holding steps; one or more drying steps can be used to further dry the composite to obtain a dried composite; one or more extruding steps; one or more calendaring steps; one or more milling steps to obtain a milled composite; one or more granulating steps; one or more cutting steps; one or more baling steps to obtain a bailed product or mixture; the baled mixture or product can be broken apart to form a granulated mixture; and/or one or more mixing or compounding steps; and/or one or more sheeting steps.

[0128] As a further example, the following sequence of steps can occur and each step can be repeated any number of times (with the same or different settings), after formation of the composite: one or more holding steps to develop further elasticity one or more cooling steps drying the composite further to obtain a further dried composite; mixing or compounding the composite to obtain a compounded mixture; milling the compounded mixture to obtain a milled mixture (e.g., roll milling); granulating the milled mixture; optionally baling the mixture after the granulating to obtain a baled mixture; optionally breaking apart the baled mixture and mixing.

[0129] Additives can also be incorporated in mixing and/or compounding steps (e.g., whether in a single-stage mix, or the second stage or third stage of a multi-stage mix); typical additives include antidegradants, zinc salts of fatty acids, processing aids (to provide ease in rubber mixing and processing, e.g. various oils and plasticizers, wax), accelerators, resins, processing oil, and/or curing agents, and vulcanized to form a vulcanizate. Other rubber additives include retarders, co-agents, peptizers, adhesion promoters (e.g., use of cobalt salts to promote adhesion of steel cord to rubber-based elastomers (e.g., as described in U.S. Pat. No. 5,221,559 and U.S. Pat. Publ. No. 2020/0361242, the disclosures of which are incorporated by reference herein), resins (e.g., tackifiers, traction resins), flame retardants, colorants, blowing agents, and additives to reduce heat build-up (HBU), and linking agents such as those described in U.S. Prov. Appl. No. 63/123,386, the disclosure of which is incorporated by reference herein. As an option, the rubber additives can comprise processing aids and activators. As another option, the rubber additives are selected from zinc oxide, fatty acids, zinc salts of fatty acids, wax, accelerators, resins, and processing oil. Exemplary resins include those selected from one or more of C5 resins, C5-C9 resins, C9 resins, rosin resins, terpene resins, aromatic-modified terpene resins, dicyclopentadiene resins, alkylphenol resins, and resins disclosed in U.S. Pat. Nos. 10,738,178, 10,745,545, and U.S. Pat. Publ. No. 2015/0283854, the disclosures of which are incorporated by reference herein. Such vulcanized compounds can have one or more improved properties, such as one or more improved rubber properties, such as, but not limited to, an improved hysteresis, wear resistance and/or rolling resistance, e.g., in tires, or improved mechanical and/or tensile strength, or an improved tan delta and/or an improved tensile stress ratio, and the like. Additives can be incorporated in mixing and/or compounding steps (e.g., whether in a single-stage mix, or the second stage or third stage of a multi-stage mix)

[0130] As an example, in a compounding step, the ingredients, with the exception of the sulfur or other cross-linking agent and accelerator, are combined with the neat composite in a mixing apparatus (the non-curatives and/or antidegradants, are often premixed and collectively termed "smalls"). The most common mixing apparatus is the internal mixer, e.g., the Banbury or Brabender mixer, but other mixers, such as continuous mixers (e.g., extruders), may also be employed. Thereafter, in a latter or second compounding step, the cross-linking agent, e.g., sulfur, and accelerator (if necessary) (collectively termed curatives) are added. As another option, the compounding can comprise combining the composite with one or more of antidegradants, zinc oxide, fatty acids, zinc salts of fatty acids, wax, accelerators, resins, processing oil, and curing agents in a single compounding stage or step, e.g., the curatives can be added with smalls in the same compounding stage. The compounding step is frequently performed in the same type of apparatus as the mixing step but may be performed on a different type of mixer or extruder or on a roll mill. One of skill in the art will recognize that, once the curatives have been added, vulcanization will commence once the proper activation conditions for the cross-linking agent are achieved. Thus, where sulfur is used, the temperature during mixing is preferably maintained substantially below the cure temperature. [0131] Also disclosed herein are methods of making a vulcanizate. The method can include the steps of at least curing a composite in the presence of at least one curing agent. Curing can be accomplished by applying heat, pressure, or both, as known in the art.

[0132] The vulcanizates prepared from the present composites (e.g., those made by any of the presently disclosed processes between wet filler, solid elastomer, and optionally filler coating agent under the disclosed mixing conditions of T_z or tip speed, whether single stage or multi-stage) can show improved properties. For example, vulcanizates prepared from the present composites can have improved properties over a vulcanizate prepared from a composite made by dry mixing solid elastomer with nonwetted filler ("dry mix composite"), particularly those dry mix composites having the same composition ("dry mix equivalent"). Thus, the comparison is made between dry mixes and the present mixing processes between comparable fillers, elastomers, filler loading (e.g., ±5 wt.%, ± 2 wt.%), and compound formulation, and optionally curing additives. Under these conditions, the vulcanizate has a tan 6 value that is less than a tan 6 value of a vulcanizate prepared from a dry mix composite having the same composition. In addition to or in the alternative, the vulcanizate has a tensile stress ratio, M300/M100, that is greater than a tensile stress ratio of a vulcanizate prepared from a dry mix composite having the same composition, wherein M100 and M300 refer to the tensile stress at 100% and 300% elongation, respectively.

[0133] Also disclosed herein are articles made from or containing the composite or vulcanizates disclosed herein.

[0134] The composite may be used to produce an elastomer or rubber containing product. As an option, the elastomer composite may be used in or produced for use, e.g., to form a vulcanizate to be incorporated in various parts of a tire, for example, tire treads (such as on road or off-road tire treads), including cap and base, undertread, innerliners, tire sidewalls, tire carcasses, tire sidewall inserts, wire-skim for tires, and cushion gum for retread tires, in pneumatic tires as well as non-pneumatic or solid tires. Alternatively or in addition, elastomer composite (and subsequently vulcanizate) may be used for hoses, seals, gaskets, weather stripping, windshield wipers, automotive components, liners, pads, housings, wheel and track elements, tire sidewall inserts, wire-skim for tires, and cushion gum for retread tires, in pneumatic tires as well as non-pneumatic or solid tires. Alternatively or in addition, elastomer composite (and subsequently vulcanizate) may be used for hoses, seals, gaskets, anti-vibration articles, tracks, track pads for track-propelled equipment such as bulldozers, etc., engine mounts, earthquake stabilizers, mining equipment such as screens, mining equipment linings, conveyor belts, chute liners, slurry pump liners, mud pump components such as impellers, valve seats, valve bodies, piston hubs, piston rods, plungers, impellers for various applications such as mixing slurries and slurry pump impellers, grinding mill liners, cyclones and hydrocyclones, expansion joints, marine equipment such as linings for pumps (e.g., dredge pumps and outboard motor pumps), hoses (e.g., dredging hoses and outboard motor hoses), and other marine equipment, shaft seals for marine, oil, aerospace, and other applications, propeller shafts, linings for piping to convey, e.g., oil sands and/or tar sands, and other applications where abrasion resistance and/or enhanced dynamic properties are desired. Further the elastomer composite, via the vulcanized elastomer composite, may be used in rollers, cams, shafts, pipes, bushings for vehicles, or other applications where abrasion resistance and/or enhanced dynamic properties are desired.

[0135] Accordingly, articles include vehicle tire treads including cap and base, sidewalls, undertreads, innerliners, wire skim components, tire carcasses, engine mounts, bushings, conveyor belt, anti-vibration devices, weather stripping, windshield wipers, automotive components, seals, gaskets, hoses, liners, pads, housings, and wheel or track elements. For example, the article can be a multi-component tread, as disclosed in U.S. Pat. Nos. 9,713,541, 9,713,542, 9,718,313, and 10,308,073, the disclosures of which are incorporated herein by reference.

[0136] The use of the terms "a" and "an" and "the" are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms "comprising," "having," "including," and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to,") unless otherwise noted. Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed. No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

Claims

1. A method of preparing a composite, comprising:

2. The method of claim 1, wherein at least 70 wt.% of the filler dispersed in the elastomer is carbon black.

3. The method of claim 1, wherein at least 80 wt.% of the filler dispersed in the elastomer is carbon black.

4. The method of claim 1, wherein the liquid is present in the wet carbon black in an amount ranging from 20% to 80% by weight based on total weight of the wet carbon black.

5. The method of any one of claims 1-4, wherein the silica is a non-wetted silica.

6. The method of any one of claims 1-4, wherein the silica is a wet silica comprising a liquid present in an amount of at least 15% by weight based on total weight of the wet silica.

7. The method of claim 6, wherein the liquid in the wet carbon black and the liquid in the wet silica can be the same or different.

8. The method of any one of claims 1-7, wherein the charging in (a) comprises charging the mixer with a blend comprising the wet carbon black and silica.

9. The method of any one of claims 1-7, wherein the charging in (a) comprises charging the mixer with separate charges of the wet carbon black and silica.

10. The method of any one of claims 1-7, wherein the charging in (a) comprises charging the mixer with a co-pellet comprising wet carbon black and silica.

11. The method of any one of claims 1-10, wherein the charging in (a) further comprises charging the mixer with a silica coating agent.

12. The method of claim 11, wherein the silica coating agent is charged to the mixer in an amount ranging from 0.5 phr to 10 phr.

13. The method of claim 11 or 12, wherein the silica coating agent is selected from polya kylene glycols, polycarboxylic acids, alkylalkoxysilanes, bifunctional silanes, alkane diols, fatty acid esters of sugars, polyamines, polyimines, and hydroxyalkylamines.

14. The method of claim 11 or 12, wherein the silica coating agent is selected from polyalkylene glycols and alkane diols.

15. The method of claim 11 or 12, wherein the silica coating agent is polyethylene glycol.

16. The method of claim 15, wherein polyethylene glycol has a weight average molecular weight ranging from 1,000 to 20,000.

17. The method of any one of claims 11-16, wherein the charging in (a) comprises charging the mixer with separate charges of wet carbon black, silica, and the silica coating agent.

18. The method of any one of claims 11-16, wherein the charging in (a) comprises charging the mixer with a co-pellet comprising the silica coating agent and at least one of the wet carbon black and silica.

19. The method of any one of claims 11-18, wherein the charging in (a) comprises multiple additions of the solid elastomer, the wet carbon black, silica, and/or the silica coating agent.

20. The method of any one of claims 11-19, wherein the charging in (a) comprises charging the mixer with the silica coating agent after the mixer reaches a temperature of at least 120°C.

21. A method of preparing a composite, comprising:

(c) discharging, from the first mixer, the mixture comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein at least 60 wt.% of the filler dispersed in the elastomer is carbon black, the mixture has a liquid content that is reduced to an amount less than the liquid content at the beginning of step (b), and the mixture has a material temperature ranging from 100°C to 180°C;

(d) mixing the mixture from (c) in a second mixer to obtain the composite; and

22. The method of claim 21, further comprising charging a silica coating agent to the first mixer, the second mixer, or both the first and second mixers.

23. The method of claim 22, wherein the silica coating agent is charged in an amount ranging from 0.5 phr to 10 phr.

24. The method of claim 22 or 23, wherein the silica coating agent is charged to the first mixer and step (b) comprises mixing the at least the solid elastomer, the wet carbon black, silica, and the silica coating agent to form the mixture.

25. The method of any one of claims 21-24, wherein the silica coating agent is charged to the second mixer and step (d) comprises mixing the mixture from (c) and the silica coating agent in the second mixer to obtain the composite.

26. A method of preparing a composite, comprising:

27. The method of claim 26, wherein at least 70 wt.% of the filler dispersed in the elastomer is at least one of silica and Silicon-treated carbon black.

28. The method of claim 26, wherein at least 80 wt.% of the filler dispersed in the elastomer is at least one of silica and Silicon-treated carbon black.

29. The method of claim 26, wherein at least 60 wt.% of the filler dispersed in the elastomer is silica.

30. The method of claim 26, wherein at least 60 wt.% of the filler dispersed in the elastomer is Silicon-treated carbon black.

31. The method of claim 26, wherein at least 60 wt.% of the filler dispersed in the elastomer is silica and Silicon-treated carbon black.

32. A method of preparing a composite, comprising:

(c) discharging, from the mixer, the composite comprising the filler dispersed in the elastomer at a loading of at least 20 phr, wherein the composite has a liquid content of no more than 10% by weight based on total weight of said composite and at least 60 wt.% of the filler dispersed in the elastomer is Silicon-treated carbon black.

33. The method of any one of claims 26-32, wherein the liquid is present in an amount ranging from 20% to 65% by weight based on total weight of the wet filler.

34. The method of any one of claims 26-32, wherein the liquid is present in an amount ranging from 30% to 65% by weight based on total weight of the wet filler.

35. The method of any one of claims 26-34, wherein the charging in (a) further comprises charging the mixer with a filler coating agent.

36. The method of claim 35, wherein the filler coating agent is charged to the mixer in an amount ranging from 0.5 phr to 10 phr.

37. The method of claim 35 or 36, wherein the filler coating agent is selected from polya kylene glycols, polycarboxylic acids, alkane diols, fatty acid esters of sugars, polyamines, polyimines, and hydroxyalkylamines.

38. The method of claim 35 or 36, wherein the filler coating agent is selected from polyalkylene glycols and alkane diols.

39. The method of claim 35 or 36, wherein the filler coating agent is polyethylene glycol.

40. The method of claim 39, wherein polyethylene glycol has a weight average molecular weight ranging from 1,000 to 20,000.

41. The method of any one of claims 35-40, wherein the charging in (a) comprises charging the mixer with separate charges of wet filler and the filler coating agent.

42. The method of any one of claims 35-40, wherein the charging in (a) comprises charging the mixer with a co-pellet comprising the filler coating agent and at least one of silica and Silicon-treated carbon black.

43. The method of any one of claims 35-42, wherein the charging in (a) comprises multiple additions of the solid elastomer, wet filler, and/or the filler coating agent.

44. The method of any one of claim 35-43, wherein the charging in (a) comprises charging the mixer with the filler coating agent after the mixer reaches a temperature of at least 120°C.

45. A method of preparing a composite, comprising:

(d) mixing the mixture from (c) in a second mixer to obtain the composite; and

46. The method of claim 45, further comprising charging a filler coating agent to the first mixer, the second mixer, or both the first and second mixers.

47. The method of claim 45 or 46, wherein the filler coating agent is charged in an amount ranging from 0.5 phr to 10 phr.

48. The method of any one of claims 45-47, wherein the filler coating agent is charged to the first mixer and step (b) comprises mixing the at least the solid elastomer, the wet filler, and the filler coating agent to form the mixture.

49. The method of any one of claims 45-48, wherein the filler coating agent is charged to the second mixer and step (d) comprises mixing the mixture from (c) and the filler coating agent in the second mixer to obtain the composite.

50. The method of any one of claims 21-25 and 45-49, wherein the first and second mixers are the same.

51. The method of any one of claims 21-25 and 45-49, wherein the first and second mixers are different.

52. The method of any one of claims 21-25 and 45-49, wherein the second mixer is operated under at least one of the following conditions:

(i) a ram pressure of 5 psi or less;

(ii) a ram raised to at least 75% of its highest level;

(iii) a ram operated in floating mode;

(iv) a ram positioned such that it does not substantially contact the mixture;

(v) the mixer is ram-less; and

(vi) a fill factor of the mixture ranges from 25% to 70%.

53. The method of any one of claims 1-52, wherein the charging in (a) further comprises charging the mixer with at least one antidegradant.

54. The method of any one of claims 1- 53, wherein said mixing is performed in one mixing step.

55. The method of any one of claims 1-53, wherein said mixing is performed in two or more mixing steps.

56. The method of any one of claims 1-55, wherein in at least one of the mixing steps, the method comprises conducting said mixing wherein the mixer has at least one temperature-control means that is set to a temperature, Tz, of 65°C or higher.

57. The method of any one of claims 1-56, wherein in at least one of the mixing steps, the method comprises conducting said mixing with one or more rotors of the mixer operating at a tip speed of at least 0.6 m/s for at least 50% of mixing time.

58. The method of any one of claims 1-57, wherein a resulting total specific energy for the mixing is at least 1,300 kJ/kg composite.

59. The method of any one of claims 1-58, wherein the filler further comprises at least one additional filler selected from carbonaceous materials, nanocellulose, lignin, clays, nanoclays, metal oxides, metal carbonates, pyrolysis carbon, graphenes, graphene oxides, reduced graphene oxide, carbon nanotubes, single-wall carbon nanotubes, multi-wall carbon nanotubes, or combinations thereof, and coated and treated materials thereof.

60. The method of any one of claims 1-59, wherein the wet carbon black is in the form of a powder, paste, pellet, or cake.

61. The method of any one of claims 1-60, wherein the solid elastomer is selected from natural rubber, functionalized natural rubber, styrene-butadiene rubber, functionalized styrene-butadiene rubber, polybutadiene rubber, functionalized polybutadiene rubber, polyisoprene rubber, ethylene-propylene rubber, isobutylene-based elastomers, polychloroprene rubber, nitrile rubber, hydrogenated nitrile rubber, polysulfide rubber, polyacrylate elastomers, fluoroelastomers, perfluoroelastomers, silicone elastomers, and blends thereof.

62. The method of any one of claims 1-61, wherein the solid elastomer is selected from natural rubber, functionalized natural rubber, styrene-butadiene rubber, functionalized styrene-butadiene rubber, polybutadiene rubber, functionalized polybutadiene rubber, and blends thereof.

63. The method of any one of claims 1-62, wherein the mixing is performed in the substantial absence of processing oil.

64. The method of any one of claims 1-63, wherein the one or more mixing steps is a continuous process.

65. The method of any one of claims 1-63, wherein the one or more mixing steps is a batch process.

66. A method of preparing a vulcanizate, comprising: curing the composite prepared by the method of any one of claims 1-65 in the presence of at least one curing agent to form the vulcanizate.

67. An article comprising the vulcanizate prepared by the method of claim 66.