Tread rubber composition with a majority of renewable components

Abstract

Tire components formed from rubber compositions comprising a majority of renewable materials. Rubber compositions comprising, based on 100 parts by weight (phr) of elastomer: a blend of at least two rubber elastomers selected from: about 40 phr to about 50 phr polybutadiene; up to about 35 phr of a styrene-butadiene copolymer; up to about 45 phr of a natural rubber; a bio-derived resin material; and a bio-derived filler comprising a silica and a carbon black filler. The carbon black filler is at least partially derived from a bio-based feedstock prior to its addition to the rubber composition. The resin and silica are also derived from renewable materials.

Description

Technical Field

[0001] This exemplary embodiment relates to a tire rubber composition containing a majority weight percentage of renewable components. Specific applications have been found in conjunction with tread components, and will be described in particular therewith. However, it should be understood that this exemplary embodiment is also adaptable to other similar applications. Background Technology

[0002] To improve sustainability in the tire industry, efforts are underway to develop rubber tire compositions from renewable sources. However, sustainable compositions must behave in the intended manner so that the tire performs as intended. Therefore, a sustainable rubber composition is desired, in which the rubber composition causes minimal or no impairment to rubber properties.

[0003] In rubber tire compounds, each material and additive is combined with an elastomer to impart specific properties to the resulting tire. Currently, several materials—two of which are resin and carbon black—are derived from fossil (also referred to herein as "hydrocarbons") fuel sources (i.e., petroleum, coal, or natural gas). Emissions from the manufacture of these petroleum-derived materials include organic matter, sulfur compounds, carbon monoxide (CO), and other pollutants. To reduce the environmental impact of these emissions, it is desirable to reduce or completely eliminate materials from fossil fuel sources from rubber compounds. However, prior technologies have made it difficult for a bio-derived alternative material, let alone its combination, to replicate the performance of conventional materials in tire compounds.

[0004] To address the challenge of providing tire rubber compositions from sustainable, biorenewable, environmentally friendly, and non-fossil fuel sources, it is desirable to evaluate rubber compositions formed from combinations of materials comprising resins derived from renewable resources. Summary of the Invention

[0005] One embodiment of this disclosure relates to a tire component formed from a rubber composition comprising a majority weight percentage of renewable material. Based on 100 parts by weight (phr) of elastomer, the rubber composition comprises:

[0006] A blend of at least two rubber elastomers, wherein the rubber elastomers are selected from:

[0007] Approximately 40 phr to approximately 50 phr of polybutadiene;

[0008] Styrene-butadiene copolymers up to approximately 35 phr;

[0009] up to approximately 45 phr of natural rubber;

[0010] Bio-derived resin materials; and

[0011] Bio-derived fillers comprising silica and carbon black fillers. In the intended embodiment, the carbon black filler is at least partially derived from bio-based raw materials before its incorporation into the rubber composition. The resin and silica are also derived from renewable materials.

[0012] The present invention discloses the following embodiments:

[0013] Option 1. A tire component formed of a rubber composition comprising a majority weight percentage of renewable material, said rubber composition comprising an elastomer based on 100 parts by weight (phr):

[0014] A blend of at least two rubber elastomers, wherein the rubber elastomers are selected from:

[0015] Approximately 40 phr to approximately 50 phr of polybutadiene;

[0016] Styrene-butadiene copolymers up to approximately 35 phr;

[0017] up to approximately 45 phr of natural rubber;

[0018] Bio-derived resin materials; and

[0019] A bio-derived filler comprising silica and carbon black filler, wherein the carbon black filler is at least partially derived from a bio-based raw material prior to its addition to the rubber composition.

[0020] Option 2. The tire component according to embodiment 1, wherein the rubber composition comprises more than about 75% renewable materials.

[0021] Option 3. The tire component according to embodiment 1, wherein the rubber composition comprises more than about 85% renewable materials.

[0022] Option 4. The tire component according to embodiment 1, wherein the resin is a terpene resin.

[0023] Option 5. The tire component according to embodiment 1, wherein the resin is α-pinene resin.

[0024] Option 6. The tire component according to embodiment 1, wherein the composition excludes petroleum-derived resins, oils, and filler materials.

[0025] Option 7. The rubber composition according to embodiment 1, wherein the blend of the rubber elastomer optionally comprises up to 35 phr of emulsion-polymerized styrene-butadiene copolymer (ESBR).

[0026] Option 8. The rubber composition according to embodiment 1, wherein the blend of the rubber elastomer excludes emulsion-polymerized styrene-butadiene copolymer (ESBR).

[0027] Option 9. The rubber composition according to embodiment 1, wherein the blend of the rubber elastomer comprises a solution-polymerized styrene-butadiene copolymer (SSBR) of about 5 to about 30 phr.

[0028] Option 10. The rubber composition according to embodiment 9, wherein the SSBR is oil-filled.

[0029] Option 11. The rubber composition according to embodiment 9, wherein the SSBR is functionalized.

[0030] Option 12. The rubber composition according to embodiment 9, wherein the SSBR is not functionalized.

[0031] Option 13. The rubber composition according to embodiment 9, wherein the blend of the rubber elastomer comprises about 5 to about 15 phr of functionalized SSBR.

[0032] Option 14. The rubber composition according to embodiment 1, wherein the blend of the rubber elastomer comprises about 35 phr to about 45 phr of natural rubber.

[0033] Option 15. The rubber composition according to embodiment 14, wherein the blend of the rubber elastomer further excludes ESBR.

[0034] Option 16. The rubber composition according to embodiment 1 further comprises:

[0035] Silica of approximately 80 phr to approximately 150 phr; and

[0036] Carbon black from 1 to approximately 15 phr.

[0037] Scheme 17. The rubber composition according to Scheme 1, wherein the silica is derived from rice husk ash.

[0038] Option 18. The rubber composition according to embodiment 1, further comprising about 10 phr to about 50 phr of resin.

[0039] Option 19. The tire component according to embodiment 1, wherein the carbon black is produced from a raw material that excludes fossil carbon before it is added to the rubber composition. Detailed Implementation

[0040] This disclosure relates to a rubber composition containing a majority weight percentage of a renewable component. This disclosure also relates to a rubber tire having tire components comprising a rubber compound.

[0041] As used herein, the terms “rubber compound,” “rubber composition,” and “compound” refer to a rubber composition containing an elastomer that has been compounded or blended with a suitable rubber compound. Unless otherwise stated, the terms “rubber,” “elastomer,” and “polymer” are used interchangeably. These terms are believed to be well known to those skilled in the art.

[0042] As used herein, unless the context otherwise requires, the term "comprising" and variations thereof, such as "covering," "including," and "comprise," are not intended to exclude additional additions, components, integers, or steps. As used herein, the word "about" means approximately and may include values ​​exceeding ±1 of the values ​​listed herein.

[0043] As used herein, the terms “bio-based” or “bio-derived” refer to materials derived from renewable or sustainable resources or natural sources, and may even include industrial sources, such as when byproducts or waste products are captured and reused to reduce or eliminate harmful emissions to the environment. A non-limiting example is the sequestration of carbon oxides used as feedstock.

[0044] As used herein, “renewable” and “sustainable” are used interchangeably and include recycled materials as well; “component” and “material” are used interchangeably. It partially, and more preferably completely, excludes radioactive carbon and fossil carbon materials derived from petroleum, coal, or natural gas. Examples of resources from which bio-based materials can be derived include, but are not limited to, fresh biomass materials (or derived from their fermentation), such as corn, vegetable oils, etc.

[0045] A key aspect of this disclosure is the weight percentage content of renewable components achieved through the use of combinations of various renewable materials. Other aspects of the disclosed rubber compositions are that the properties of cured rubber compositions having a majority weight percentage of renewable components meet or improve upon the tread (wet, abrasion, and rolling resistance) properties of conventional rubber compositions made from petroleum-derived materials.

[0046] One or more rubber polymers

[0047] The disclosed rubber compositions comprise at least two rubbers, and more particularly blends of conjugated diene-based elastomers. In fact, various conjugated diene-based elastomers can be used in the rubber compositions, such as polymers and copolymers of at least one of isoprene and 1,3-butadiene, and polymers and copolymers of styrene copolymerized with at least one of isoprene and 1,3-butadiene. Examples of such conjugated diene-based elastomers include, for example, at least one of cis-1,4-polyisoprene (natural and synthetic), cis-1,4-polybutadiene, styrene / butadiene copolymers, medium-vinyl polybutadiene with a vinyl 1,2-content of about 15% to about 90%, isoprene / butadiene copolymers, and styrene / isoprene / butadiene terpolymers.

[0048] In practice, preferred rubbers or elastomers are polyisoprene (natural or synthetic), polybutadiene, and SBR. In a further embodiment, the rubber elastomer is polyisoprene and polybutadiene. In one embodiment, polybutadiene is present in a large quantity. In a preferred embodiment, polyisoprene is present in a large quantity.

[0049] In one embodiment, the rubber composition comprises about 30 phr to about 60 phr of polybutadiene, and more preferably about 40 phr to about 50 phr of polybutadiene. In another embodiment, the rubber composition comprises up to 20% by weight of polybutadiene.

[0050] In practice, cis-1,4-polybutadiene elastomers can be considered as cis-1,4-polybutadiene rubbers prepared using neodymium catalysts, which can be prepared, for example, by polymerizing 1,3-polybutadiene monomers in an organic solvent solution in the presence of a catalyst system containing neodymium compounds. However, such 1,4-polybutadiene can alternatively be prepared as cis-1,3-butadiene rubber via nickel catalysis in an organic solution.

[0051] Representatives of cis-1,4-polybutadiene prepared by this neodymium catalyst are, for example, but not intended to be limiting, BUD 1223™ from The Goodyear Tire & Rubber Company and CB25™ from Lanxess.

[0052] Cis-1,4-polyisoprene and cis-1,4-polyisoprene natural rubber are well known to those skilled in the art of rubber. In practice, the second rubber polymer may contain polyisoprene. In one embodiment, polyisoprene may be present in a small amount. In another embodiment, polyisoprene may be present in a large amount. In practice, preferred rubbers or elastomers contain a certain amount of polyisoprene (natural or synthetic). In one embodiment, the rubber composition comprises up to about 45 phr of polyisoprene, preferably in the form of natural rubber. In one embodiment, the rubber composition comprises at least about 35 phr of polyisoprene, preferably in the form of natural rubber. In some embodiments, the rubber composition comprises about 35 phr to about 45 phr of polyisoprene in the form of natural rubber. In one embodiment, the rubber composition comprises about 10 to about 35 wt% of polyisoprene, and more preferably about 15 to about 30 wt% of polyisoprene.

[0053] In one considered embodiment, at least one rubber polymer comprises styrene-butadiene rubber. The styrene / butadiene copolymer comprises those prepared by aqueous emulsion polymerization (ESBR) and organic solvent solution polymerization (SSBR). In one embodiment, solution-polymerized SBR (SSBR) is also considered, typically having a bound styrene content of about 9% to about 36%. However, embodiments in which the SSBR has a bound styrene content greater than 30%, for example, 34%, are also considered.

[0054] The rubber composition may contain up to about 35 phr of styrene-butadiene rubber. In one embodiment, the rubber composition contains ESBR and SSBR. In another embodiment, the rubber composition contains SSBR and excludes ESBR. For embodiments in which the blend of rubber polymers contains SSBR, SSBR may be present in an amount of about 5 phr to about 30 phr, and more preferably about 10 to about 25 phr. In some embodiments, the rubber composition contains up to about 5% by weight of SSBR.

[0055] SSBR can be readily prepared, for example, by organolithium catalysis in the presence of an organic hydrocarbon solvent. In one embodiment, SSBR is not functionalized. In another embodiment, at least one rubber polymer, such as SSBR, can be functionalized.

[0056] A representative example of a functionalized elastomer is a styrene / butadiene elastomer containing one or more functional groups, said functional groups including

[0057] (A) The amine functional group reacts with the hydroxyl groups on the precipitated silica.

[0058] (B) A silanoxy functional group containing a terminal silanoxy group reacts with a hydroxyl group on precipitated silica.

[0059] (C) A combination of amine and silanoxy functional groups, which reacts with the hydroxyl groups on the precipitated silica.

[0060] (D) A combination of mercapto and silyloxy (e.g., ethoxysilane) functional groups, which reacts with the hydroxyl groups on precipitated silica.

[0061] (E) A combination of imine and silyloxy functional groups that react with hydroxyl groups on precipitated silica; (F) A hydroxyl functional group that reacts with precipitated silica.

[0062] For functionalized elastomers, a representative example of amine-functionalized SBR elastomers is, for example, the in-chain functionalized SBR elastomer mentioned in U.S. Patent No. 6,936,669.

[0063] A representative example of a combination of amino-silyloxy-functionalized SBR elastomers having one or more amino-silyloxy groups linked to the elastomer is, for example, the amino-silyloxy-functionalized SBR elastomer mentioned in JSR HPR355™ and U.S. Patent No. 7,981,966.

[0064] For example, representative styrene / butadiene elastomers terminally functionalized with silane-sulfide groups are mentioned in U.S. Patent Nos. 8,217,103 and 8,569,409.

[0065] Furthermore, it is anticipated that in some embodiments, the rubber elastomer may be a butyl rubber, particularly a copolymer of isobutylene with a small amount of one or more dienes, such as isoprene and halogenated butyl rubber.

[0066] Furthermore, in some embodiments, the elastomer may comprise a halogenated butyl rubber comprising a blend of chlorobutyl rubber, brominated butyl rubber, and mixtures thereof.

[0067] Tin-coupled elastomers can also be used, such as styrene / butadiene copolymers, isoprene / butadiene copolymers, styrene / isoprene copolymers, polybutadiene, and styrene / isoprene / butadiene terpolymers prepared by tin-coupled organic solution polymerization of functionalized styrene / butadiene elastomers.

[0068] Oil

[0069] It is desirable that the rubber composition contains less or no petroleum-derived materials, meaning that the rubber composition will contain a minimal (if any) amount of petroleum-based processing oil. For example, it is desirable that the rubber composition is limited to zero to about 5 phr of petroleum-based processing oil, and more preferably less than about 2 phr of rubber-based petroleum processing oil.

[0070] In one embodiment, the rubber composition may contain up to about 20 phr of rubber processing oil. In another embodiment, the rubber composition may contain not less than about 1 phr of rubber processing oil. In practice, the composition may contain about 1 to about 20 phr of rubber processing oil, and more preferably about 15 to about 20 phr. The processing oil may be included in the rubber composition as an increment oil typically used to fill elastomers. The processing oil may also be included in the rubber composition by adding oil directly during the rubber compounding process. The processing oil used in the rubber composition may include both the increment oil present in the elastomer and the process oil added during the compounding process. Suitable processing oils include a variety of oils known in the art, including aromatic oils, alkyl oils, naphthenic oils, vegetable triglyceride oils, and low PCA oils, such as MES, TDAE, SRAE, and heavy naphthenic oils. Suitable low PCA oils include those having a polycyclic aromatic hydrocarbon content of less than 3% by weight as determined by the IP346 method. The procedure for the IP346 method is available at [link to relevant documentation]. Standard Methods for Analysis & Testing of Petroleum and Related Products and British Standard 2000 Parts, 2003 , 62nd edition, published by the Institute of Petroleum, United Kingdom.

[0071] Suitable vegetable triglyceride oils comprise a combination of saturated and unsaturated esters, wherein the unsaturated esters comprise a combination of at least one of oleic acid, linoleic acid ester, and linoleic acid ester. Saturated esters may include, for example, but not limited to, at least one of stearate and palmitate.

[0072] In one embodiment, the vegetable triglyceride oil comprises at least one of soybean oil, sunflower oil, rapeseed oil, and low-erucic acid rapeseed oil, in the form of an ester containing a certain degree of unsaturation. Other suitable examples of vegetable triglyceride oils include corn oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, and safflower oil. In practice, the oil comprises at least one of soybean oil and sunflower oil.

[0073] For example, in the case of soybean oil, the percentage distribution or combination of fatty acids in glycerol triesters (triglycerides) as shown above is expressed as an average and can vary to some extent, primarily depending on the type or source of the soybean crop, and also depending on the growing conditions of the specific soybean crop from which the soybean oil is obtained. Other saturated fatty acids are also typically present in significant quantities, although these usually do not exceed 20% of soybean oil.

[0074] The intended embodiment includes approximately 1% to 10% by weight of a bio-derived rubber processing oil in the composition. In one embodiment, the rubber processing oil material constitutes approximately 3% to 8% by weight of the composition.

[0075] resin

[0076] A key aspect of this disclosure is the use of bio-derived resin materials to partially, but preferably completely, replace petroleum resins. Conventional resins are derived from petroleum. These types of resins comprise any hydrocarbon chemical type resin (AMS, benzofuran-indene, C5, C9, C5 / C9, DCPD, DCPD / C9, others) and any modifications thereof (phenol, C9, hydrogenated, recycled monomers, others). While these types of resins are considered for use in one embodiment of the invention, preferred embodiments alternatively use renewable bio-based chemical type resins and their modifications and mixtures. Representative resins may also include benzofuran-type resins, including benzofuran-indene resins and benzofuran resins, mixtures of naphthenic oils, phenolic resins, and rosin. Other suitable resins include phenol-terpene resins, such as phenol-acetylene resins, phenol-formaldehyde resins, alkylphenol-formaldehyde resins, terpene-phenol resins, polyterpene resins, and xylene-formaldehyde resins.

[0077] Terpene-phenol resins can be used. Terpene-phenol resins can be obtained by copolymerizing phenol monomers with terpenes such as limonene, pinene, and δ-3-carene. In one embodiment, the resin can be an α-pinene resin characterized by a softening point Tg of 60°C to 130°C.

[0078] In one embodiment, the resin is a resin derived from rosin and its derivatives. Examples include, for instance, gum rosin, wood rosin, and tall oil rosin. Gum rosin, wood rosin, and tall oil rosin have similar compositions, although the amounts of the rosin components can vary. This resin can be dimerized, polymerized, or disproportionated. This resin can be in the form of an ester of rosin acid and a polyol such as pentaerythritol or a diol.

[0079] In one embodiment, the resin may be partially or fully hydrogenated.

[0080] In one embodiment, the rubber composition comprises at least one resin of about 10 to about 80 phr, and more preferably about 10 to about 80 phr of a bio-derived resin, although embodiments in which another resin of a different type may also be incorporated into the composition are also contemplated. In one embodiment, the rubber composition comprises not less than 15 phr of resin, and more preferably not less than about 20 phr of resin. In one embodiment, the rubber composition comprises not less than 20 phr of resin and not more than 60 phr of resin.

[0081] The considered embodiments include about 10% to 15% by weight of bio-resin material in the composition. In one embodiment, the resin material accounts for about 12% to 15% by weight of the composition.

[0082] filler

[0083] The disclosed rubber composition contains 80 to 150 phr of silica filler. In one embodiment, the composition contains at least 90 phr of silica. In another embodiment, the composition contains not less than 100 phr of silica.

[0084] In one embodiment, precipitated silica comprises the following:

[0085] (A) Precipitated silica derived from inorganic sand (silica-based sand), or

[0086] (B) Precipitated silica derived from rice husks (rice husks containing silica).

[0087] In one embodiment, precipitated silica is derived from naturally occurring inorganic sand (e.g., SiO2, silica, which may contain trace minerals). The inorganic sand is typically treated with a strong base, such as sodium hydroxide, to form an aqueous silicate solution (e.g., sodium silicate). Precipitated silica is synthesized by controlled treatment of the silicate with an acid (e.g., an inorganic acid and / or an acidifying gas, such as carbon dioxide). Sometimes, an electrolyte (e.g., sodium sulfate) may be present to promote the formation of precipitated silica particles. The recovered precipitated silica is amorphous.

[0088] In a preferred embodiment, the precipitated silica is rice husk-derived precipitated silica. This precipitated silica is derived from the outer shell of the rice plant (e.g., from the ash of burning rice husks), containing SiO2, silica, and possibly trace minerals from the soil from which the rice was grown. In similar methods, rice husks (e.g., rice husk ash) are typically treated with a strong alkali (e.g., sodium hydroxide) to form an aqueous silicate solution (e.g., sodium silicate), followed by controlled treatment of the silicate with an acid (e.g., an inorganic acid and / or an acidifying gas, such as carbon dioxide), thereby forming synthetic precipitated silica, in which an electrolyte (e.g., sodium sulfate) may be present to promote the formation of rice husk-derived precipitated silica particles. The recovered precipitated silica is amorphous precipitated silica. See, for example, U.S. Patent Application Ser. No. 2003 / 0096900. In a preferred embodiment, the rubber composition comprises 30 to 40% by weight of rice husk ash silica, and more preferably 34 to 37% by weight of rice husk ash silica.

[0089] Precipitated silica, whether derived from the aforementioned silica or rice husk, can, for example, have a BET surface area of ​​about 40 to about 600, and more typically about 50 to about 300 m² / g, as measured using nitrogen. BET methods for measuring surface area can be described, for example... Journal of the American Chemical Society Volume 60, and ASTM D3037.

[0090] This precipitated silica may also have, for example, dibutyl phthalate (DBP) absorbance values, such as about 100 to about 400, and more typically about 150 to about 300 cc / 100g.

[0091] Other implementation schemes were considered, in which silica was used in combination with another filler such as carbon black.

[0092] In one embodiment, the rubber composition optionally comprises, based on 100 parts by weight (phr) of elastomer, about 0 to about 50 phr of carbon black. In one embodiment, the rubber composition comprises no more than 20 phr of carbon black. In another embodiment, the rubber composition comprises not less than 0.1 phr of carbon black, and in some embodiments, not less than 1 phr of carbon black. In one embodiment, the rubber composition comprises about 1 to about 15 phr of carbon black. In a preferred embodiment, the carbon black is bio-based carbon black.

[0093] The "biobased" content obtained by the ASTM-D6866 method is based on the same concept as radiocarbon dating, but does not use a dating equation. The method relies on determining the radiocarbon content in an unknown sample. 14C) The ratio of the amount of carbon to the amount of modern reference standard. The ratio is expressed as a percentage in the unit "pMC" (modern carbon percentage). If the material being analyzed is a mixture of current radioactive carbon and fossil carbon (derived from petroleum, coal, or natural gas), then the obtained pMC value is directly related to the amount of biomass material present in the sample.

[0094] Before excess radiocarbon was introduced into the atmosphere, the modern reference standard for radiocarbon dating was the National Institute of Standards and Technology USA (NIST-USA) standard, which had a known radiocarbon content approximately equal to AD 1950. AD 1950 represents 0 years and 100 pMC. Modern (fresh) biomass materials and those derived from them give radiocarbon values ​​close to 107.5.

[0095] Radiocarbon dating isotopes (¹⁴C) have a nuclear half-life of 5730 years. Depending on its origin, fossil carbon has an ¹⁴C content very close to zero. By assuming 10⁷.5 pMC represents modern biomass material and 0 pMC represents petroleum (fossil carbon) derivatives, the measured pMC value of the material will reflect the ratio of the two component types. Therefore, material 100% derived from modern vegetable oils will produce a radiocarbon label close to 10⁷.5 pMC. If the material is diluted with 50% petroleum derivatives, it will give a radiocarbon label close to 54 pMC.

[0096] Biomass content results are obtained by specifying 100% as 107.5 pMC and 0% as 0 pMC. At this point, a sample measuring 99 pMC will give an equivalent biomass content result of 93%. This value is called the "average biomass result" and assumes that all components in the analyzed material are of modern, extant, or fossil origin.

[0097] The results provided by the ASTM D6866 method are average bio-based results and include a 6% absolute range (±3% on either side of the average bio-based result) to calculate the variation in the final component's radiocarbon labeling. All materials are assumed to be of modern or fossil origin. The results represent the amount of bio-based component "present" in the material—not the amount of bio-based material "used" in the manufacturing process.

[0098] In one embodiment, the tire component is formed of a rubber composition comprising carbon black filler having a modern carbon content of greater than one percent (1%), as defined in ASTM D6866. The carbon black is produced from bio-based raw materials prior to its addition to the rubber composition. In one embodiment, the carbon black is at least partially derived from bio-based raw materials, and in a preferred embodiment, it is completely free of fossil carbon.

[0099] In one embodiment, the bio-based raw material for obtaining carbon black comprises at least one triglyceride vegetable oil, such as soybean oil, sunflower oil, low-erucic acid rapeseed oil, rapeseed oil, or combinations thereof. In another embodiment, the bio-based raw material for deriving carbon black comprises at least one plant biomass, animal biomass, and municipal waste biomass, or combinations thereof.

[0100] In one embodiment, the carbon black has a modern carbon content of at least 1%. In another embodiment, the carbon black has a modern carbon content of at least about 10%, more preferably at least about 25%, and most preferably at least about 50%. In one embodiment, the carbon black has a biomass content of at least about 1 pMC, and more preferably at least about 54 pMC. In one embodiment, the carbon black may have a biomass content of at least about 80 pMC.

[0101] Other embodiments consider the use of carbon-reinforced fillers that generate carbon dioxide. Suitable carbon-reinforced materials that generate carbon dioxide can be produced using methods described in, for example, US 8,679,444; US 10,500,582 and US Ser. No. 17 / 109,262 (each of which is incorporated herein by reference in its entirety).

[0102] Various combinations of carbon black (with different particle sizes and / or other properties, including conventional petroleum-based carbon black) can also be used in disclosed rubber compositions. A representative example of rubber-reinforcing carbon black is, for example, and not intended to be limiting, its ASTM name, see The Vanderbilt Rubber Handbook, 13th edition, 1990, pp. 417 and 418. This rubber-reinforcing carbon black can have, for example, an iodine absorption of 60-240 g / kg and a DBP value of 34-150 cc / 100g.

[0103] Coupling agent

[0104] A representative example of the silica coupling agent for precipitated silica is:

[0105] (A) Contains, on average, about 2 to about 4, or about 2 to about 2.6, or about 3.2 to about 3.8 sulfur atoms in its connecting bridges, or

[0106] (B) Alkoxy-based mercaptosilanes, or

[0107] (C) Their combination.

[0108] Representative examples of such bis(3-trialkoxysilylalkyl) polysulfides include bis(3-triethoxysilylpropyl) polysulfides.

[0109] It is desirable to incorporate the silica discussed above into the rubber composition, in combination with bis(3-triethoxysilylpropyl) polysulfide, for its in-situ reaction within the rubber composition.

[0110] In one embodiment, the composition comprises about 1 phr to about 20 phr of coupling agent, and more preferably about 8 phr to about 12 phr of coupling agent.

[0111] Processing aids - fatty acid derivatives

[0112] Another aspect of this disclosure is the addition of a bio-derived processing aid to a rubber composition. In a preferred embodiment, the processing aid may be a bio-based fatty acid derivative and / or a blend of one or more bio-based fatty acid derivatives. The processing aid may have a softening point (Tg) of about 105°C to about 120°C. Typically, about 0.5 to about 5 phr, and more preferably about 1 to about 3 phr, of the processing aid may be included in the composition. In a contemplated embodiment, the processing aid is obtained from Struktol® or other forms in ZB 49. In some embodiments, the processing aid may be used to promote coupling between coupling agents, silica fillers, and / or portions on the polymer, forming an interpolymer network.

[0113] Those skilled in the art will readily understand that rubber compositions are compounded using methods commonly known in the field of rubber compounding, such as mixing various sulfur-vulcanizable component rubbers with a variety of commonly used additive materials, such as sulfur donors, curing aids like activators, accelerators and scorch inhibitors, processing additives, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants and ozone agents, and plasticizers. As is known to those skilled in the art, the additives mentioned above are selected and typically used in conventional amounts depending on the intended use of the sulfur-vulcanizable and sulfur-vulcanizable materials (rubbers).

[0114] Representative examples of sulfur donors include elemental sulfur (free sulfur), disulfides of amines, polymeric polysulfides, and sulfur olefin adducts. Preferably, the sulfur-sulfurizing agent is elemental sulfur. The sulfur-sulfurizing agent can be used in amounts of 0.5 to 8 phr, preferably 1 to 6 phr. Typical amounts of antioxidants include about 0.5 to about 5 phr. Representative antioxidants can be, for example, polymerized trimethyldihydroquinoline, mixtures of aryl-p-phenylenediamine, and others, such as those disclosed, for example, in The Vanderbilt Rubber Handbook (1978), pages 344-346. In a preferred embodiment, the antioxidant is a lignin-based antioxidant. Typical amounts of antiozone agents include about 1 to 5 phr. Non-limiting representative antiozone agents can be, for example, N-(1,3-dimethylbutyl)-n'-phenyl-p-phenylenediamine. If a fatty acid is used, it may contain stearic acid as an example, and its typical amount may include about 0.5 to about 5 phr. The typical amount of zinc oxide is about 1 to about 5 phr. In a preferred embodiment, the zinc oxide is derived from recycled components. The typical amount of wax is about 1 to about 5 phr. Microcrystalline wax is typically used, but refined paraffin wax or a combination of both may also be used. The typical amount of plasticizer is about 0.1 to about 1 phr. Typical plasticizers may be, for example, pentachlorothiophenol and dibenzoylaminodiphenyl disulfide.

[0115] Accelerators are used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanized rubber. In one embodiment, a single accelerator system, i.e., a primary accelerator, can be used. The total amount of one or more primary accelerators available is from about 0.2 to about 3, preferably from about 2 to about 2.5 phr. In another embodiment, a combination of a primary accelerator and a secondary accelerator can be used, wherein the secondary accelerator is used, for example, in a total amount of from about 0.2 to about 3 phr, preferably from about 2 to about 2.5 phr, to activate and improve the properties of the vulcanized rubber. These combinations of accelerators are expected to produce a synergistic effect on the final properties and are to some extent better than those produced by using any single accelerator alone. In addition, delayed-acting accelerators can be used, which are not affected by normal processing temperatures but produce satisfactory curing at ordinary vulcanization temperatures. Scorch inhibitors can also be used. A non-limiting example of a scorch inhibitor may be N-cyclohexylthiophthalimide (CTP). Suitable types of accelerators that can be used in this invention are amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates, and xanthate esters / salts. Preferably, the primary accelerator is a sulfenamide, such as, for example, N-cyclohexyl-2-benzothiazole sulfenamide (CBS). If an auxiliary accelerator is used, it is preferably a guanidine (e.g., diphenylguanidine (DPG)), a dithiocarbamate (e.g., zinc dimethyl dithiocarbamate or zinc dibenzyl dithiocarbamate), or a thiuram compound.

[0116] The mixing of rubber compositions can be accomplished by methods known to those skilled in the art of rubber mixing. For example, components are typically mixed in at least two stages: at least one non-production stage followed by a production mixing stage. The final curing agent, containing a vulcanizing agent, is typically mixed in the final stage, often referred to as the "production" mixing stage, where mixing is usually carried out at a temperature or final temperature lower than one or more mixing temperatures of the preceding one or more non-production mixing stages. The terms "non-production" and "production" mixing stages are well known to those skilled in the art of rubber mixing. Rubber compositions may undergo a thermomechanical mixing step. A thermomechanical mixing step typically involves mechanically processing the rubber in a mixer or extruder for a suitable time to achieve a rubber temperature of 140°C to 190°C. The suitable duration of thermomechanical processing varies with operating conditions and variations in the volume and properties of the components. For example, thermomechanical processing can be from 1 to 20 minutes.

[0117] The vulcanization of the pneumatic tires of the present invention is typically carried out at a conventional temperature of about 100°C to 200°C. Preferably, vulcanization is carried out at a temperature of about 110°C to 180°C. Any commonly used vulcanization method can be used, such as heating in a press or mold, heating with superheated steam or hot air. Such tires can be manufactured, shaped, molded, and cured by various methods known and readily apparent to those skilled in the art.

[0118] This disclosure contemplates tire components formed by this method. Similarly, tire components can be incorporated into a tire. Tire components can be ground-contact or non-ground-contact. Tires can be pneumatic or non-pneumatic. In one embodiment, the component can be a tread.

[0119] The tires disclosed herein can be racing tires, bus tires, aircraft tires, agricultural tires, bulldozer tires, off-road tires, truck (commercial or passenger) tires, etc. Preferably, the tires are bus or truck tires. The tires can also be radial or bias-ply, with radial being preferred.

[0120] The rubber composition itself, depending primarily on the selection and level of renewable materials, can also be used as tire sidewalls or other tire components, or for applications in rubber tracks, conveyor belts, or other industrial products, such as windshield wiper blades, brake diaphragms, gaskets, seals, washers, hoses, conveyor belts, power transmission belts, shoe soles, shoe uppers, and floor mats for building or automotive applications.

[0121] For illustrative purposes and not for limiting the scope of the invention, the following embodiments are provided. All parts are by weight unless otherwise expressly stated. Example

[0122] These embodiments illustrate the effect of the combination of the disclosed renewable components on the properties of the rubber compounds. The rubber compositions were mixed in a multi-step mixing process according to the formulations in Tables 1-6.

[0123] Control rubber compounds A, D, F, K, N, and Q were formed from the same amounts of similar components. These control samples were formed using blends of polybutadiene (BR), emulsion-polymerized styrene-butadiene copolymer (ESBR), and solution-polymerized styrene-butadiene polymer (ESBR) with additive materials comprising soybean oil, carbon black filler, bio-based silane coupling agent, wax, anti-ozone agent, lignin-based antioxidant, bio-based fatty acid derivative blends, and recycled zinc oxide. The controls were also formed using petroleum-derived α-methylstyrene resin. Standard curing techniques were also used.

[0124] Example 1

[0125] Experimental samples B and C are shown in Table 1. In samples B and C, the petroleum resin was replaced with a bio-derived resin—more specifically, α-pinene resin. Sample C also contained eight percent (8%) more sulfur and accelerator than control A, while all other components and amounts were the same.

[0126] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0127] The basic formulation is shown in Table 1 below, expressed in parts per 100 parts by weight of elastomer (phr). Table 1 also compares the curing properties of control sample A and experimental samples B and C.

[0128] Table 1

[0129]

[0130]

[0131] 1 Polybutadiene, Nd-catalyzed

[0132] 2 Solution-polymerized styrene-butadiene rubber, 33% styrene, 20 phr oil filler

[0133] 3 α-methylstyrene resin

[0134] 4 Bio-based terpene resin, SYLVATRAXX 8115, is derived from Kraton Chemical.

[0135] 5 CBS

[0136] Table 1 shows a slight directional shift towards lower stiffness between experimental sample B and control A when petroleum-derived resin was replaced with bio-derived resin. The change was modulated by adding sulfur and accelerators between experimental sample C and experimental sample B (both formed using bio-derived resin). This improved the δ-torque value of sample C, which better matched that of control A.

[0137] In summary, similar performance parameters were observed between experimental samples B and C and control sample A. It can be concluded that the performance of the rubber compound is not affected by the availability of sustainably sourced resins used to replace petroleum-based resins.

[0138] Example 2

[0139] Experimental sample E is shown in Table 2. In sample E, conventional petroleum-derived carbon black was replaced with bio-derived carbon black. Sample E contained a greater amount of carbon black than control D, while all other quantities were the same.

[0140] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0141] The basic formulation is shown in Table 2 below, expressed in parts per 100 parts by weight of elastomer (phr). Table 2 also compares the curing properties of control sample D and experimental sample E.

[0142]

[0143]

[0144] *The same formulation as control sample A, as described above.

[0145] 1 Carbon black derived from CO2 feedstock

[0146] Table 2 shows that when petroleum-derived carbon black was replaced by bio-derived carbon black, the low strain stiffness between experimental sample E and control D increased.

[0147] In summary, the results show that bio-derived carbon black has no significant impact on the properties of the rubber compound. Therefore, it can be concluded that bio-derived carbon black can be used as a colorant without significantly affecting the properties of the rubber compound.

[0148] Example 3

[0149] Experimental sample GJ is shown in Table 3. In sample GJ, ESBR was replaced with natural rubber, along with a reduction in SSBR. Sample G used a conventional blend of petroleum-derived resin and modified rubber. Sample HJ used a bio-derived resin material instead of petroleum-derived resin. Samples I and J used an increased amount of bio-derived resin material compared to sample H. Sample J also had an increased amount of silica filler compared to sample FI. Minor curing adjustments were made between samples H, I, and J, where the amounts of all other components remained the same.

[0150] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0151] The basic formulation is shown in Table 3 below, expressed as parts per 100 parts by weight of elastomer (phr). Table 3 also compares the curing properties of control sample F and experimental sample GJ.

[0152]

[0153]

[0154] *The formulation is the same as that of control samples A and D, as described above.

[0155] 1 Polybutadiene, Nd-catalyzed

[0156] 2 Solution-polymerized styrene-butadiene rubber, 33% styrene, 20 phr oil filler

[0157] 3 α-methylstyrene resin

[0158] 4 Bio-based terpene resin, SYLVATRAXX 8115, is derived from Kraton Chemical.

[0159] In Example 3, the rubber polymer blend was adjusted to achieve a lower polymer Tg transition. Experimental samples (GJ) were tested to evaluate the effect of increased levels of bio-derived resin and / or silica on the expected properties.

[0160] By switching to natural rubber, sample H showed an increase at low strain stiffness. The transition to a lower polymer Tg resulted in a negative impact on wetland properties, but showed improved abrasion, snow, and rolling resistance properties.

[0161] By doubling the amount of bio-derived resin, Sample I showed a significant improvement in wetland properties, but at the cost of rolling resistance. Increased plasticizer levels were directionally beneficial to snow properties. Overall, the compound's stiffness was reduced.

[0162] By adding more silica and other modifications, sample J showed restored stiffness. Snow performance also showed comparable results to control F.

[0163] The study concludes that performance characteristics can be controlled and the percentage of renewable / sustainable components can be adjusted by increasing the amount of bio-derived resin materials and silica in tires. This polymer composition can be incorporated into the tire tread.

[0164] Example 4

[0165] Table 4 shows experimental sample L, which was improved by further replacing petroleum-derived carbon black with an equal amount of bio-derived carbon black (using an increased amount of bio-derived resin material), as described above. In sample M, the nonfunctionalized SSBR of control K and sample L was replaced with functionalized SSBR. The soybean oil level was also adjusted to maintain the plasticizer level of the oil-filled SSBR in samples K and L.

[0166] Minor curing adjustments were made between samples H, I, and J, where all other component amounts remained the same. Sample L had the same other components and amounts as sample J, but contained a bio-derived resin instead of the petroleum resin in control K, and a larger amount of silica filler. Minor curing adjustments were also made to sample K.

[0167] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0168] The basic formulation is shown in Table 4 below, expressed as parts per 100 parts by weight of elastomer (phr). Table 4 also compares the curing properties of control sample K with experimental samples L and M.

[0169]

[0170]

[0171] *The formulation is the same as that of control samples A, D, and F, as described above.

[0172] The formulation is the same as that of sample J above, except that bio-based carbon black has been added.

[0173] 1 Solution-polymerized styrene-butadiene rubber, 33% styrene, 20 phr oil-filled

[0174] 2 SSBR, 33% styrene, 20 phr oil-filled

[0175] 3 SSBR, 21% styrene, functionalized Sn

[0176] 4 α-methylstyrene resin

[0177] 5 Bio-based terpene resin, SYLVATRAXX 8115, is derived from Kraton Chemical.

[0178] 6 Rice husk ash silica

[0179] 7 Carbon black derived from CO2 feedstock

[0180] Example 2 shows that replacing petroleum-derived carbon black with bio-derived carbon black has no effect on the properties of the rubber compound. Here, combinations of bio-derived carbon black and bio-derived resin materials were tested with high silica content and functionalized SBR. Using functionalized SBR instead of non-functionalized SBR showed improved rolling resistance. Minimal impact on other performance indicators was observed. Therefore, it is concluded that functionalized polymers can be used in conjunction with a variety of other bio-derived materials in tire tread rubber compositions.

[0181] Example 5

[0182] Experimental sample O had the same formulation as sample M described above. Sample P adjusted the polymer ratio of sample O, while keeping all other components and amounts the same. This change resulted in an increase in the percentage (content) of renewable materials in the composition.

[0183] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0184] The basic formulation is shown in Table 5 below, expressed as parts per 100 parts by weight of elastomer (phr). Table 5 also compares the curing properties of control sample N and experimental samples O and P.

[0185]

[0186]

[0187]

[0188] *The formulation is the same as that of control samples A, D, F, and K, as described above.

[0189] **The same formulation as sample M, as described above.

[0190] 1 SSBR, 33% styrene, 20 phr oil-filled

[0191] 2 SSBR, 21% styrene, functionalized, Sn

[0192] 3 α-methylstyrene resin

[0193] 4 Bio-based terpene resin, SYLVATRAXX 8115, is derived from Kraton Chemical.

[0194] 5 Rice husk ash silica

[0195] 6 Carbon black derived from CO2 feedstock

[0196] Prior to this example, sample M showed the most favorable performance results. In Example 5, the blending ratio of the three polymers was adjusted and compared with sample M. This adjustment resulted in a change in polymer Tg from -80.0°C to -82.6°C (FOX calculation).

[0197] The increased natural rubber component in experimental sample P resulted in increased compound stiffness and true tensile strength. Compared to control N, sample P showed improved wet, abrasion, and snow performance, while also exhibiting a significant increase in the percentage of renewable material components. Rolling resistance was also comparable to or improved upon control N and sample O.

[0198] Table 6

[0199] Experimental sample R has the same formulation as sample P described above. In sample S, a larger amount of natural rubber was used instead of ESBR. All other components and amounts remained the same. This change resulted in a further increase in the percentage (content) of renewable materials in the composition.

[0200] The rubber compound is then cured and tested for various properties, including wear, wet traction, and rolling resistance.

[0201] The basic formulation is shown in Table 6 below, expressed as parts per 100 parts by weight of elastomer (phr). Table 6 also compares the curing properties of control sample Q and experimental samples R and S.

[0202]

[0203]

[0204] *The formulation is the same as that of control samples A, D, F, K, and N, as described above.

[0205] **The same formulation as samples M and P, as described above.

[0206] 1 SSBR, 33% styrene, 20 phr oil-filled

[0207] 2SSBR, 21% styrene, functionalized, Sn

[0208] 3 α-methylstyrene resin

[0209] 4 Bio-based terpene resin, SYLVATRAXX 8115, is derived from Kraton Chemical.

[0210] 5 Rice husk ash silica

[0211] 6 Carbon black derived from CO2 feedstock

[0212] To further test the increased percentage of renewable components in the tread, SBR was removed and replaced with another type of natural rubber. Furthermore, in this embodiment, natural rubber constituted the majority of the rubber polymer in the blend with a significant increase. This resulted in a change in the polymer Tg (FOX calculated) from -82.6°C to -72.3°C.

[0213] Polymer conditioning resulted in a slight decrease in the stiffness of the compound.

[0214] The increase in the natural rubber level increased the percentage of renewable components in the rubber composition from 47% by weight (control Q) to 88% by weight (experimental sample S). Sample S showed improved wet and snow performance indicators compared to control Q, and also showed comparable rolling resistance.

[0215] The conclusion is that tread tire rubber compositions with a majority percentage of renewable components, formed by combining different renewable materials, can meet or improve the performance of tires formed by conventional rubber compositions.

[0216] Variations may be made in this invention, based on the description provided herein. Although certain representative embodiments and details have been shown for illustrative purposes, it will be apparent to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention. Therefore, it should be understood that changes may be made in the specific embodiments described, which will be within the full contemplated scope of the invention as defined by the following appended claims.

Claims

1. A tire component formed from a rubber composition, the rubber composition comprising, based on 100 parts by weight of elastomer: 40 to 50 phr polybutadiene; and at least one of the following rubber elastomers: up to 35 phr solution polymerized styrene-butadiene copolymer; and up to 45 phr natural rubber; 10 to 80 phr of a bio-derived resin material, wherein the bio-derived resin material is a terpene resin and / or an alpha pinene resin; and a bio-derived filler comprising 80 to 150 phr of silica and 1 to 15 phr of carbon black filler, wherein the carbon black filler is at least partially derived from a CO2 feedstock prior to its addition to the rubber composition, wherein phr denotes parts per 100 parts by weight of elastomer.

2. The tire component of claim 1, wherein the rubber composition comprises greater than 75 weight percent renewable material.

3. The tire component of claim 1, wherein the rubber composition comprises greater than 85 weight percent renewable material.

4. The tire component of claim 1, wherein the composition excludes petroleum derived resins, petroleum derived oils, and petroleum derived filler materials.

5. A rubber composition comprising, based on 100 parts by weight of elastomer: 40 to 50 phr polybutadiene; and at least one of the following rubber elastomers: up to 35 phr solution polymerized styrene-butadiene copolymer; and up to 45 phr natural rubber; 10 to 80 phr of a bio-derived resin material, wherein the bio-derived resin material is a terpene resin and / or an alpha pinene resin; and a bio-derived filler comprising 80 to 150 phr of silica and 1 to 15 phr of carbon black filler, wherein the carbon black filler is at least partially derived from a CO2 feedstock prior to its addition to the rubber composition, wherein phr denotes parts per 100 parts by weight of elastomer.

6. The rubber composition of claim 5, wherein the blend of rubber elastomers optionally comprises up to 35 phr of emulsion polymerized styrene butadiene copolymer.

7. The rubber composition of claim 5, wherein the blend of rubber elastomers excludes emulsion polymerized styrene butadiene copolymer.

8. The rubber composition of claim 5, wherein the blend of rubber elastomers comprises 5 to 30 phr of solution polymerized styrene butadiene copolymer.

9. The rubber composition of claim 8, wherein the solution polymerized styrene butadiene copolymer is oil extended.

10. The rubber composition of claim 8, wherein the solution polymerized styrene butadiene copolymer is functionalized.

11. The rubber composition of claim 8, wherein the solution polymerized styrene butadiene copolymer is not functionalized.

12. The rubber composition of claim 8, wherein the blend of the rubber elastomer comprises a functionalized solution-polymerized styrene-butadiene copolymer at 5 to 15 phr.

13. The rubber composition of claim 5, wherein the blend of the rubber elastomer comprises natural rubber of 35 phr to 45 phr.

14. The rubber composition of claim 13, wherein the blend of the rubber elastomer further excludes emulsion-polymerized styrene-butadiene copolymers.

15. The rubber composition according to claim 5, wherein the silica is derived from rice husk ash.

16. The rubber composition according to claim 5, further comprising 10 phr to 50 phr of resin.

17. The tire component of claim 1, wherein the carbon black is produced from a raw material that excludes fossil carbon before it is added to the rubber composition.

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