Rubber compositions and tires

Abstract

Rubber compositions and tires are disclosed. In a first aspect, the invention relates to a rubber composition comprising 70 phr to 100 phr of a styrene butadiene rubber comprising a first styrene butadiene rubber having a glass transition temperature in the range of -49°C to -15°C and a second styrene butadiene rubber having a glass transition temperature in the range of -50°C to -89°C. Further, the rubber composition comprises 10 phr to 30 phr of one or more of a natural rubber and a synthetic polyisoprene rubber, 40 phr to 70 phr of a silica, and 10 phr to 40 phr of at least one hydrocarbon resin selected from one or more of a C5 resin, a CPD resin, a DCPD resin, a C9 modified C5 resin, a C9 modified CPD resin, and a C9 modified DCPD resin. In another aspect, the invention relates to a tire comprising a tire tread having the above rubber composition.

Description

Technical Field

[0001] This invention relates to rubber compositions, particularly tread rubber compositions, and tires comprising rubber compositions, especially tires comprising a tread having said rubber compositions. Background Technology

[0002] As is known in the tire industry, it is traditionally difficult to improve multiple tire characteristics simultaneously without a significant compromise on at least one other characteristic. One such conflict exists between rolling resistance and wet performance. When improving rolling resistance, there is usually a trade-off in wet grip. However, limiting rolling resistance is crucial for improving energy efficiency. Another potential issue is keeping wear at a limited level, which helps prevent rapid tire wear and contributes to a sustainable product, preferably along with good ride and handling properties.

[0003] Therefore, there is still a need to provide new rubber compounds, especially tread rubber compounds, which improve the balance among several of the aforementioned properties. Summary of the Invention

[0004] A primary objective of this invention may be to provide a rubber composition having improved hysteresis / rolling resistance properties and good wet performance.

[0005] Another object of the present invention may be to provide a rubber composition that, when used in a tire tread, has improved properties and / or improved wear properties or tread abrasion properties as described above.

[0006] This invention is defined by the independent claims. Preferred embodiments are provided in the dependent claims and in the summary of the invention provided below.

[0007] Therefore, in a first aspect of the invention, a rubber composition is provided comprising 70 phr to 90 phr of styrene-butadiene rubber (preferably solution-polymerized styrene-butadiene rubber), comprising a first styrene-butadiene rubber with a glass transition temperature in the range of -15°C to -49°C and a second styrene-butadiene rubber with a glass transition temperature in the range of -50°C to -89°C, and one or more of natural rubber and synthetic polyisoprene with a glass transition temperature of 10 phr to 30 phr, 40 phr to 70 phr of silica, and at least one hydrocarbon resin with a glass transition temperature of 10 phr to 40 phr, said hydrocarbon resin being selected from one or more of C5 (aliphatic) resin, CPD (cyclopentadiene) resin, DCPD (dicyclopentadiene) resin, C9 (aromatic) modified C5 resin, C9 modified CPD resin, and C9 modified DCPD resin.

[0008] Such rubber compositions, which contain a limited amount of silica and the aforementioned resin types, as well as styrene-butadiene rubber with a relatively high glass transition temperature and styrene-butadiene rubber with a relatively low glass transition temperature, enable further improvement in hysteresis properties or rolling resistance performance, while essentially maintaining or even improving wet grip properties.

[0009] In one embodiment, the resin (particularly a hydrocarbon resin) has one or more of the following: a softening point in the range of 80°C to 150°C, preferably in the range of 90°C to 110°C; a weight-average molecular weight in the range of 500 g / mol to 1000 g / mol, preferably in the range of 500 g / mol to 800 g / mol; and a glass transition temperature in the range of 30°C to 60°C, preferably 40°C to 60°C, or even more preferably 40°C to 55°C; and an aromatic proton content (or in other words, aromaticity) determined by NMR analysis in the range of 5% to 15%, preferably 8% to 12%. The weight-average molecular weight (Mw) is determined using gel permeation chromatography (GPC) according to ASTM 5296-11 using polystyrene calibration standards.

[0010] The inventors have identified this type of resin as a particularly preferred candidate.

[0011] In yet another embodiment, the resin is a hydrogenated (preferably fully hydrogenated) hydrocarbon resin.

[0012] In yet another embodiment, the C5 resin is an aliphatic resin prepared from one or more of the following monomers: 1,3-pentadiene (e.g., cis or trans), 2-methyl-2-butene, cyclopentene, cyclopentadiene, and dicyclopentadiene.

[0013] In yet another embodiment, the C9 modified resin is a resin that has been modified or functionalized with one or more aromatic monomers (e.g., C5 resin), wherein the aromatic monomers are preferably selected from indene, methylindene, vinyltoluene, styrene, and methylstyrene (e.g., α-methylstyrene).

[0014] In yet another embodiment, the rubber composition comprises 50 phr to 65 phr of silica. The inventors have determined this range to be the most preferred range for the compositions of the invention.

[0015] In another embodiment, the BET surface area of ​​silica is 190 m². 2 / g to 260 m 2 / g, preferably 205 m 2 / g to 260 m 2 Within the range of / g. In particular, such relatively high surface area silica has been found to be most desirable in the compositions of the present invention.

[0016] In yet another embodiment, the rubber composition further comprises 0.1 phr to 10 phr of carbon black, preferably 0.5 phr to 5 phr. In particular, it is desirable that the compositions of the present invention comprise a limited amount of carbon black.

[0017] In yet another embodiment, the rubber composition further comprises a silane of 4 to 10 phr, preferably a terminal mercaptosilane of 4 to 8 phr, such as 3-octanoylthio-1-propyltriethoxysilane. The latter silane is particularly preferred to further improve rolling resistance properties while limiting further compromises.

[0018] In yet another embodiment, the rubber composition comprises a liquid plasticizer (e.g., oil, liquid resin, and / or liquid diene polymer) of 0 to 10 phr. Hereinafter, the term liquid plasticizer means that the plasticizer is in a liquid state at a temperature of 23°C. Preferably, the composition comprises a liquid plasticizer of less than 5 phr, particularly an oil of less than 5 phr.

[0019] In yet another embodiment, the rubber composition comprises 40 phr to 65 phr (preferably 60 phr) of a first styrene-butadiene rubber and / or 25 phr (preferably 30 phr) to 50 phr of a second styrene-butadiene rubber, wherein the first styrene-butadiene rubber is preferably at least 5 phr more than the second styrene-butadiene rubber.

[0020] In yet another embodiment, the rubber composition comprises 15 phr to 25 phr of natural rubber or synthetic polyisoprene, and / or preferably less than 23 phr of natural rubber or synthetic polyisoprene rubber. In particular, the claimed range of natural rubber or synthetic polyisoprene rubber has been found to be particularly desirable for achieving good tensile properties.

[0021] In yet another embodiment, at least one of the first and second styrene-butadiene rubbers comprises at least one functional group configured for coupling with silica. Such functional groups are preferably selected from one or more of polysiloxy, alkylsiloxy, aminoalkylsiloxy, tinamino, aminosiloxane, and aminosilyl groups. Preferably, the functional group is located at one or more chain ends of one or more of the styrene-butadiene rubbers.

[0022] In yet another embodiment, both styrene-butadiene rubbers contain at least one functional group configured for coupling with silica.

[0023] In yet another embodiment, one of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with at least one aminosilyl group (preferably at one chain end or even more preferably at both chain ends), and the other of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with at least one aminosiloxane group (preferably at at least one chain end).

[0024] In yet another embodiment, the glass transition temperature of the first styrene-butadiene rubber is in the range of -20°C to -40°C, preferably -20°C to -35°C, and / or the glass transition temperature of the second styrene-butadiene rubber is in the range of -51°C to -69°C, preferably -55°C to -69°C.

[0025] Among other things, the combination of high-Tg styrene-butadiene rubber and low-Tg styrene-butadiene rubber enables a better balance between traction and wear, especially compared to using only one type of relatively high-Tg styrene-butadiene rubber.

[0026] In yet another embodiment, the first styrene-butadiene rubber has a styrene content of 5% to 50%, preferably 10% to 35%, and most preferably 20% to 35%; and / or the second styrene-butadiene rubber has a styrene content of 5% to 30%, and preferably 5% to 15%.

[0027] In another embodiment, the rubber composition comprises 15 phr to 35 phr, preferably up to 30 phr of resin. For example, the rubber composition may contain 15 phr to 30 phr of resin.

[0028] In yet another embodiment, the rubber composition comprises 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane. In particular, this crosslinking agent is intended to further improve the abrasion resistance of the rubber compositions according to one or more of the foregoing embodiments.

[0029] In yet another embodiment, the glass transition temperature of the rubber composition is in the range of -25°C to -15°C. In particular, a lower glass transition temperature will reduce wetland performance.

[0030] In one embodiment, the rubber composition may comprise at least one additional diene-based rubber. Representative synthetic polymers may be homopolymers of butadiene and its homologues and derivatives (e.g., methylbutadiene, dimethylbutadiene, and pentadiene), as well as copolymers, such as those formed from butadiene or its homologues or derivatives with other unsaturated monomers. The latter may in particular be acetylenes, such as vinylacetylene; olefins, such as isobutene, which copolymerize with isoprene to form butyl rubber; vinyl compounds, such as acrylic acid, acrylonitrile (which polymerizes with butadiene to form NBR), methacrylic acid, and styrene, the latter of which polymerizes with butadiene to form SBR; and vinyl esters and various unsaturated aldehydes, ketones, and ethers, such as acrolein, methyl isopropenyl ketone, and vinyl ethyl ether. Specific examples of synthetic rubbers include chloroprene rubber (polychloroprene), polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, halogenated butyl rubbers such as chloroprene rubber or bromobutyl rubber, styrene / isoprene / butadiene rubber, copolymers of 1,3-butadiene or isoprene with monomers such as styrene, acrylonitrile, and methyl methacrylate, and ethylene / propylene terpolymers, also known as ethylene / propylene / diene monomers (EPDM), and particularly ethylene / propylene / dicyclopentadiene terpolymers. Further examples of rubbers that can be used include alkoxy-silyl-terminated solution-polymerized polymers (SBR, PBR, IBR, and SIBR), silane-coupled and tin-coupled star-branched polymers. Preferred rubbers or elastomers are typically natural rubber, synthetic polyisoprene, polybutadiene, and SBR, including SSBR.

[0031] In another embodiment, an emulsion polymerization-derived styrene / butadiene (ESBR) with a styrene content of 20% to 28% bound styrene can be used, or for some applications, an ESBR with a medium to relatively high bound styrene content, i.e., 30% to 45%, can be used. In many cases, the ESBR has a bound styrene content in the range of 26% to 31%. The styrene-butadiene rubber (ESBR) prepared by emulsion polymerization can refer to a copolymer of styrene and 1,3-butadiene in the form of an aqueous emulsion. This is well known to those skilled in the art. The bound styrene content can be varied, for example, from 5% to 50%. In one aspect, the ESBR may also contain acrylonitrile to form a terpolymer rubber, as ESBAR, in an amount, for example, 2 to 30% by weight of bound acrylonitrile in the terpolymer. Styrene / butadiene / acrylonitrile copolymer rubbers prepared by emulsion polymerization containing 2 to 40% by weight of bound acrylonitrile in the copolymer are also contemplated as diene-based rubbers.

[0032] In another embodiment, a solution-polymerized (or solution-polymerized) SBR (SSBR) can be used, for example, for the claimed styrene-butadiene rubber. SSBR can be conveniently prepared, for example, by anionic polymerization in an inert organic solvent. More specifically, SSBR can be synthesized by copolymerizing styrene and 1,3-butadiene monomers in a hydrocarbon solvent using an organolithium compound as an initiator. In yet another embodiment, the solution-polymerized styrene-butadiene rubber is a tin-coupled polymer. In yet another embodiment, the SSBR is functionalized to improve compatibility with silica. Furthermore, or alternatively, the SSBR is thio-functionalized. This helps improve the stiffness and / or hysteretic behavior of the compound. Thus, for example, the SSBR can be a thio-functionalized tin-coupled solution-polymerized butadiene-styrene copolymer.

[0033] In one embodiment, synthetic or natural polyisoprene rubber may be used. Synthetic cis-1,4-polyisoprene and natural rubber are well known to those skilled in the art of rubber. Specifically, the cis-1,4-microstructure content of synthetic cis-1,4-polyisoprene is typically at least 90% and more typically at least 95%. In some cases, the synthetic cis-1,4-polyisoprene will have a cis-1,4-microstructure content in the range of 95% to 99%.

[0034] In one embodiment, cis-1,4-polybutadiene rubber (BR or PBD) is used. Suitable polybutadiene rubber can be prepared, for example, by organic solution polymerization of 1,3-butadiene. BR can be conveniently characterized, for example, by having at least 90% cis-1,4-microstructure content (“high cis” content) and a glass transition temperature (Tg) in the range of -95°C to -110°C. Suitable polybutadiene rubber is commercially available, for example, Budene® 1207, Budene® 1208, Budene® 1223, or Budene® 1280 from The Goodyear Tire & Rubber Company. These high cis-1,4-polybutadiene rubbers can be synthesized, for example, using a nickel catalyst system comprising (1) an organonitrile compound, (2) an organoaluminum compound, and (3) a fluorinated compound, as described in U.S. Patents 5,698,643 and 5,451,646. In another preferred embodiment, the rubber composition is substantially free of or contains no PBD.

[0035] The glass transition temperature, or Tg, of an elastomer represents the glass transition temperature of the corresponding elastomer in its uncured state. The glass transition temperature of an elastomer composition represents the glass transition temperature of the elastomer composition in its cured state. In this paper, Tg is determined by differential scanning calorimetry (DSC) at a heating rate of 10 °C / min, using the midpoint of the peak value, according to ASTM D3418.

[0036] The Tg of the resin is determined by differential scanning calorimetry (DSC) at a heating rate of 10 °C / min as the midpoint of the peak value, according to ASTM D6604 or an equivalent method. Preferably, the resin has a softening point above 100 °C as determined herein by ASTM E28, which may sometimes be referred to as the ring and ball softening point.

[0037] As used herein, and in accordance with conventional practice, the term "phr" refers to "parts by weight of the corresponding material of rubber or elastomer per 100 parts by weight." Typically, using this convention, a rubber composition comprises 100 parts by weight of rubber / elastomer. The claimed composition may contain other rubber / elastomers besides those expressly mentioned in the claims, provided that the phr value of the claimed rubber / elastomer conforms to the claimed phr range, and the total amount of all rubber / elastomers in the composition results in a total of 100 parts of rubber. In one example, the composition may further comprise one or more additional diene-based rubbers, such as SBR, SSBR, ESBR, PBD / BR, NR, and / or synthetic polyisoprene, of 1 phr to 10 phr, optionally 1 phr to 5 phr. In another example, the composition may comprise less than 5 phr, preferably less than 3 phr, of additional diene-based rubber, or substantially none of such additional diene-based rubber. Unless otherwise indicated, the terms "rubber compound," "composition," and "formulation" are used interchangeably herein. The terms "rubber" and "elastomer" are also used interchangeably herein unless otherwise indicated.

[0038] In one embodiment, the rubber composition may also contain oil, particularly processing oil. Processing oil may be included in the rubber composition as an additive oil typically used in incremental elastomers. Processing oil may also be included in the rubber composition by adding oil directly during the rubber compounding process. The processing oil used may include additive oils present in the elastomer, as well as processing oils added during compounding. Suitable oils may include a variety of oils known in the art, including aromatic oils, paraffinic oils, naphthenic oils, vegetable oils, and low-PCA oils such as MES, TDAE, SRAE, and heavy naphthenic oils. Suitable low-PCA oils may include those with 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 in 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. Some representative examples of vegetable oils that can be used include soybean oil, sunflower oil, rapeseed oil, corn oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, and safflower oil. Soybean oil and corn oil are generally preferred vegetable oils.

[0039] Common silica pigments that can be used in rubber compounds include, for example, conventional pyrolytic and precipitated silica pigments (silica). In one embodiment, precipitated silica is used. Conventional silica pigments can be precipitated silica, such as those obtained by acidification of soluble silicates (e.g., sodium silicate). Such conventional silica can be characterized, for example, by having a BET surface area measured using nitrogen. In one embodiment, the BET surface area can be in the range of 100 to 300 m² / g. In another embodiment, the BET surface area can be in the range of 200 to 300 m² / g. In embodiments of the invention, the surface area is preferably relatively high. The BET surface area is determined according to ASTM D6556 or an equivalent scheme and described in the Journal of the American Chemical Society, Vol. 60, p. 304 (1930).

[0040] In yet another embodiment, the rubber composition may comprise pre-silanized and precipitated silica. In yet another embodiment, the pre-silanized, or in other words, pre-hydrophobicated precipitated silica is hydrophobized by treatment with at least one silane before being added to the rubber composition. Suitable silanes include, but are not limited to, alkylsilanes, alkoxysilanes, organoalkoxysilyl polysulfides, and organothiol alkoxysilanes. Non-limiting examples of pretreated silica (i.e., silica that has been pre-surface-treated with silanes) suitable for the practice of this invention include, but are not limited to, Ciptane® 255 LD and Ciptane® LP (PPGIndustries) silica that have been pretreated with mercaptosilanes, and Coupsil® 8113 (Degussa) and Coupsil® 6508, Coupsil® 6508, Agilon® 400 silica from PPG Industries, Agilon® 454 silica from PPG Industries, and Agilon® 458 silica from PPG Industries.

[0041] In one embodiment, the rubber composition does not include the addition of (added) precipitated silica to the rubber composition (therefore, it does not include the addition of non-presilanized precipitated silica).

[0042] In one embodiment, the rubber composition may comprise carbon black. Some representative examples of such carbon blacks include grades N110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990, and N991. These carbon blacks have iodine absorbance ranging from 9 g / kg to 145 g / kg and a 34 cm⁻¹ iodine content. 3 / 100 g to 150 cm 3 / 100 g DBP value. Iodine absorbance can be appropriately determined according to ASTM D1510 or an equivalent protocol.

[0043] In one embodiment, the rubber composition may comprise a sulfur-containing organosilicon compound or a silane. Examples of suitable sulfur-containing organosilicon compounds have the following formula: Z is selected from: Where R 1 It is an alkyl group, cyclohexyl group, or phenyl group with 1 to 4 carbon atoms; R 2 Alk is an alkoxy group with 1 to 8 carbon atoms, or a cycloalkoxy group with 5 to 8 carbon atoms; Alk is a divalent hydrocarbon with 1 to 18 carbon atoms, and n is an integer from 2 to 8. In one embodiment, the sulfur-containing organosilicon compound is a 3,3'-bis(trimethoxy or triethoxysilylpropyl) polysulfide. In one embodiment, the sulfur-containing organosilicon compound is a 3,3'-bis(triethoxysilylpropyl) disulfide and / or a 3,3'-bis(triethoxysilylpropyl) tetrasulfide. Therefore, with respect to formula I, Z can be... Where R 2 Alk is an alkoxy group with 2 to 4 carbon atoms, or alternatively, an alkoxy group with 2 carbon atoms; Alk is a divalent hydrocarbon with 2 to 4 carbon atoms, or alternatively, a divalent hydrocarbon with 3 carbon atoms; and n is 2 to 5, or alternatively, an integer of 2 or 4. In another embodiment, a suitable sulfur-containing organosilicon compound includes the compounds disclosed in U.S. Patent 6,608,125. In a preferred embodiment, the sulfur-containing organosilicon compound includes 3-(octanoylthio)-1-propyltriethoxysilane, CH3(CH2)6C(=O)―S―CH2CH2CH2Si(OCH2CH3)3, which can be used as NXT TM Purchased from Momentive Performance Materials. In another embodiment, suitable sulfur-containing organosilicon compounds include those disclosed in U.S. Patent Application Publication No. 2003 / 0130535. In one embodiment, the sulfur-containing organosilicon compound is Si-363 from Degussa. The amount of the sulfur-containing organosilicon compound in the rubber composition can be varied depending on the level of other additives used.

[0044] It will be readily understood by those skilled in the art that rubber compositions can be compounded using methods commonly known in the field of rubber compounding, such as mixing various sulfur-vulcanizable rubber components with a variety of commonly used additive materials (e.g., sulfur donors, curing aids such as activators and retarders, and processing additives such as oils, resins, including tackifying resins and plasticizers, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants and anti-ozone agents, and plasticizers). As is known to those skilled in the art, the aforementioned additives are selected according to the intended use of the sulfur-vulcanizable material and the sulfur-vulcanizable material (rubber) and are generally used in conventional amounts. Some representative examples of sulfur donors include elemental sulfur (free sulfur), amine disulfides, polymeric polysulfides, and sulfur olefin adducts. In one embodiment, the sulfur-vulcanizing agent is elemental sulfur. The sulfur-vulcanizing agent can be used, for example, in amounts ranging from 0.5 phr to 8 phr, or alternatively from 1.5 phr to 6 phr. If a tackifying resin is used, typical amounts include, for example, 0.5 phr to 5 phr, and typically 1 phr to 5 phr. However, in a preferred embodiment, the composition does not contain such a tackifying resin. If an antioxidant is used, its typical amount may include, for example, 1 phr to 5 phr. Representative antioxidants may include, for example, diphenyl-p-phenylenediamine, such as those disclosed in The Vanderbilt Rubber Handbook (1978), pages 344-346. If an anti-ozone agent is used, its typical amount may include, for example, 1 phr to 5 phr. If a fatty acid (which may include stearic acid) is used, its typical amount may include, for example, 0.5 phr to 3 phr. If a wax is used, its typical amount may include, for example, 1 phr to 5 phr. Microcrystalline waxes are used in many cases. If a plasticizer is used, its typical amount may include, for example, 0.1 phr to 1 phr. Typical plasticizers may be, for example, pentachlorothiophenol and diphenylcarbamate diphenyl disulfide.

[0045] Accelerators are preferred, but not mandatory, for controlling the time and / or temperature required for vulcanization and for improving the properties of the vulcanized rubber. In one embodiment, a single accelerator system, i.e., a primary accelerator, can be used. One or more primary accelerators can be used in total amounts of 0.5 phr to 4 phr, or alternatively 0.8 phr to 1.5 phr. In another embodiment, a combination of a primary accelerator and a secondary accelerator can be used, with the secondary accelerator used in smaller amounts, e.g., 0.05 phr to 3 phr, to activate and improve the properties of the vulcanized rubber. It is expected that the combination of these accelerators will produce a synergistic effect on the final properties and will be, to some extent, better than those produced by using any one accelerator alone. Furthermore, accelerators with delayed curing effects that are not affected by normal processing temperatures but produce satisfactory curing at ordinary vulcanization temperatures can be used. Vulcanization delay agents can also be used. Suitable types of accelerators that can be used in this invention are, for example, amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates, and xanthates. In one embodiment, the primary accelerator is a sulfenamide. If a co-accelerator is used, it can be, for example, a guanidine, a dithiocarbamate, or a thiuram compound. Suitable guanidines include diphenylguanidine, etc. Suitable thiurams include tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabenzylthiuram disulfide.

[0046] Rubber compositions can be mixed using methods known to those skilled in the art of rubber compounding. For example, components can typically be mixed in at least two stages: at least one non-productive stage and a subsequent productive mixing stage. Final curing agents, including vulcanizing agents, can typically be incorporated in the final stage, commonly referred to as the “productive” mixing stage, where mixing is usually carried out at a temperature or final temperature lower than the mixing temperature of one or more of the preceding non-productive mixing stages. The terms “non-productive” and “productive” mixing stages are well known to those skilled in the art of rubber compounding. In one embodiment, the rubber composition can be subjected to a thermomechanical mixing step. The thermomechanical mixing step typically involves mechanical processing in a mixer or extruder for a period of time, for example, a period suitable for producing rubber temperatures from 140°C to 190°C. The appropriate 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.

[0047] In a second aspect of the invention, a tire is provided comprising the rubber composition of the first aspect and / or one of the embodiments thereof.

[0048] In one embodiment, the tire includes a tire tread, the tire tread comprising the rubber composition.

[0049] In another implementation, the tires are summer tires.

[0050] In yet another embodiment, the tire includes a tire tread with a crown, the crown comprising at least two layers (in the radial direction of the tire) at least partially disposed on top of each other, wherein a rubber composition is provided in the radially outermost crown layer (which contacts the ground when driving). Alternatively or additionally, the rubber composition is provided in the radially inner crown layer (disposed radially below the radially outermost crown layer).

[0051] In yet another embodiment, the rubber composition is contained in a radially inner crown layer having a substantially U-shaped or substantially L-shaped cross-section, wherein the radially inner crown layer contacts the road surface in one or both shoulder areas of the tread during driving, and the radially outer or outermost crown layer contacts the road surface in the central area of ​​the tread and optionally in one of the shoulder areas of the tread.

[0052] In another embodiment, the tire of the present invention can be, for example, a pneumatic tire or a non-pneumatic tire. The tire can also be a radial tire or a bias-ply tire. Preferably, the tire is a radial pneumatic tire.

[0053] In one embodiment, the vulcanization of the pneumatic tire of the present invention can be carried out, for example, at a conventional temperature of 100°C to 200°C. In another embodiment, vulcanization is carried out at a temperature in the range of 110°C to 180°C. Any commonly used vulcanization process can be used, such as heating in a press or mold, heating with superheated steam or hot air. Such tires can be constructed, shaped, molded, and cured by various methods known and obvious to those skilled in the art.

[0054] It should be emphasized that, within the scope of this invention, one or more aspects, embodiments, or features thereof can be combined with each other.

[0055] More specifically, this invention discloses a tire comprising a generally annular carcass and a peripheral tread, two sidewalls, two spaced-apart beads, at least one ply extending from the beads to the bead, and sidewalls extending radially from the tread to the beads and connecting the tread to the beads, wherein the tread is adapted to contact the ground, and wherein the peripheral tread comprises a rubber composition comprising: (a) 70 phr to 90 phr of styrene-butadiene rubber, the styrene-butadiene rubber comprising a first styrene-butadiene rubber having a glass transition temperature in the range of -49°C to -15°C and a second styrene-butadiene rubber having a glass transition temperature in the range of -50°C to -89°C; (b) 10 phr to 30 phr of natural rubber and one or more of synthetic polyisoprene; (c) 40 phr to 70 phr of silica; and (d) 10 phr to 40 phr of natural rubber. phr has at least one hydrocarbon resin, said hydrocarbon resin being selected from one or more of C5 resin, CPD resin, DCPD resin, C9 modified C5 resin, C9 modified CPD resin, and C9 modified DCPD resin.

[0056] The present invention discloses the following embodiments: Option 1. A rubber composition comprising: Styrene-butadiene rubber of 70 phr to 90 phr, wherein the styrene-butadiene rubber comprises a first styrene-butadiene rubber with a glass transition temperature in the range of -49°C to -15°C and a second styrene-butadiene rubber with a glass transition temperature in the range of -50°C to -89°C. 10 phr to 30 phr is selected from one or more members of natural rubber and synthetic polyisoprene rubber; 40 phr to 70 phr of silica; and At least one hydrocarbon resin with a concentration of 10 phr to 40 phr, wherein the hydrocarbon resin is selected from one or more of C5 resin, CPD resin, DCPD resin, C9 modified C5 resin, C9 modified CPD resin, and C9 modified DCPD resin.

[0057] Option 2. The rubber composition according to Option 1, characterized in that the resin has a softening point in the range of 80°C to 150°C and a weight-average molecular weight in the range of 500 g / mol to 1000 g / mol.

[0058] Option 3. The rubber composition according to Option 1 or 2, characterized in that the resin has one or more of the following: Softening point in the range of 90℃ to 110℃; Weight-average molecular weight in the range of 500 g / mol to 800 g / mol; Glass transition temperature in the range of 30°C to 60°C.

[0059] Option 4. A rubber composition according to one or more of the foregoing options, characterized in that the resin is selected from one or more of C9 modified CPD and C9 modified DCPD resins; and / or the resin has an aromatic proton content in the range of 5% to 15%.

[0060] Option 5. A rubber composition according to one or more of the foregoing options, characterized in that the resin is at least partially hydrogenated.

[0061] Option 6. A rubber composition according to one or more of the foregoing options, characterized in that the rubber composition comprises 50 phr to 65 phr of the silica.

[0062] Option 7. A rubber composition according to one or more of the foregoing options, characterized in that the BET surface area of ​​the silica is 190 m². 2 / g to 260 m 2 Within the range of / g, preferably in the range of 205 m 2 / g to 260 m 2 Within the range of / g.

[0063] Option 8. The rubber composition according to one or more of the foregoing options, characterized in that it further comprises one or more of the following: Carbon black from 0.1 phr to 10 phr; Enhanced silanes from 4 phr to 8 phr; 4 phr to 7 phr capped mercaptosilanes; Liquid plasticizers from 0 phr to 10 phr.

[0064] Scheme 9. A rubber composition according to one or more of the foregoing schemes, characterized in that it comprises 40 phr to 65 phr of the first styrene-butadiene rubber and 25 phr to 50 phr of the second styrene-butadiene rubber.

[0065] Scheme 10. A rubber composition according to one or more of the foregoing schemes, characterized in that at least one of the first styrene-butadiene and the second styrene-butadiene comprises at least one functional group configured for coupling with the silica, optionally, the functional group being selected from one or more of polysiloxy, alkylsiloxy, aminoalkylsiloxy, tinamino, aminosiloxane and aminosilyl groups.

[0066] Option 11. A rubber composition according to one or more of the foregoing options, characterized in that each styrene-butadiene rubber comprises at least one functional group configured for coupling with silica; and wherein optionally, one of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with an aminosilyl group, and the other of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with an aminosiloxane group.

[0067] Scheme 12. The rubber composition according to one or more of the foregoing schemes, characterized in that the glass transition temperature of the first styrene-butadiene rubber is in the range of -20°C to -35°C, and the glass transition temperature of the second styrene-butadiene rubber is in the range of -55°C to -69°C.

[0068] Option 13. A rubber composition according to one or more of the foregoing options, characterized in that it comprises the resin at 15 phr to 30 phr.

[0069] Scheme 14. A rubber composition according to one or more of the foregoing schemes, characterized in that the glass transition temperature of the rubber composition is in the range of -25°C to -15°C.

[0070] Option 15. A tire (1) having a tread (10), wherein the tread (10) comprises a rubber composition according to one or more of the foregoing options. Attached Figure Description

[0071] The structure, operation, and advantages of the invention will become more apparent when considered in conjunction with the accompanying drawings, in which: Figure 1 It is a schematic cross-section of a tire, including the tread and other rubber components. Detailed Implementation

[0072] Figure 1 This is a schematic cross-section of a pneumatic tire 1. The tire 1 has a tread 10, an airtight layer 13, a belt layer structure including four belted ply layers 11, a carcass ply 9, two sidewalls 2, and two bead regions 3 including a bead filler triangular core 5 and a bead 4. The exemplary tire 1 is, for example, suitable for mounting on the rim of a vehicle such as a truck or bus. Figure 1As shown, the belt ply 11 can be covered by the overlay ply 12. The carcass ply 9 includes a pair of axially opposed ends 6, each associated with a corresponding one of the bead 4. Each axial end 6 of the carcass ply 9 can be reversed and positioned around the corresponding bead 4 to anchor each axial end 6. The reversed portion 6 of the carcass ply 9 can engage the axially outer surfaces of the two bead core wraps 8 and the axially inner surfaces of the two heel reinforcement layers 7. Figure 1 As shown, the exemplary tread 10 may have four circumferential grooves, each groove substantially defining a U-shaped opening in the tread 10. According to embodiments of the invention, the tread 10 comprises one or more tread compounds as described herein.

[0073] Although Figure 1 The proposed embodiments include multiple tire components, such as a triangular core 5, a heel reinforcement layer 7, a bead core wrap 8, and a cover 12; however, such components are not mandatory for this invention. Furthermore, the reverse-wrapped end of the carcass ply 9 is not essential for this invention, or it may pass through the opposite side of the bead region 3 and terminate axially inside the bead 4 rather than axially outside the bead 4. The tire may also have, for example, more or fewer than four tread grooves. This invention should not be limited to those described above. Figure 1 An example of a tire 1 that is depicted and described.

[0074] Preferred embodiments of the rubber compositions according to embodiments of the present invention, namely Examples 1 to 4 (particularly applicable to tire tread 10), are shown in Table 1 in comparison with two comparative Examples 1 and 2 not according to the present invention. All examples comprise a combination of natural rubber (polyisoprene) and styrene-butadiene rubber. In particular, the presence of polyisoprene rubber is considered beneficial for the composition type of the present invention in terms of a well-balanced tensile property. Furthermore, all examples are based on combinations of high-Tg styrene-butadiene rubber and low-Tg styrene-butadiene rubber listed in Table 1.

[0075] All compositions (except Comparative Example 1) rely on moderate amounts of high surface area silica, with Examples 2 and 4 of the present invention having even higher surface area silica types. The embodiments of the present invention also contain end-capped mercaptosilanes, while the comparative examples primarily rely on bis-triethoxysilylpropyl disulfide type silanes. Regarding resins, the comparative examples contain terpene resins, while the embodiments of the present invention contain DCPD resin types. Furthermore, all examples contain 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (BDBzTH), which is primarily used to support the abrasion resistance of the composition, an important property for many tread rubber compositions.

[0076] Table 1 1 SLR3402 is a sulfur-functionalized solution-polymerized styrene-butadiene rubber from Trinseo, with a Tg of -62℃. 2 HPR355H is a styrene-butadiene rubber produced by solution polymerization of aminosilane-functionalized styrene from JSR, with a Tg of -27℃. 3 F1038 is a styrene-butadiene rubber derived from the solution polymerization of aminosiloxane-functionalized rubber by LG Chem, with a Tg of -62°C and an oil content of 5% by weight. 4 As Zeosil TM Premium 200MP precipitated silica, with a BET surface area of ​​approximately 215 m². 2 / g 5 Precipitated silica, BET surface area is approximately 250 m² 2 / g 6 As NXT TM 3-Octaylthio-1-propyltriethoxysilane from Momentive 7 SI 266 is a bis-triethoxysilylpropyl disulfide from Evonik. 8 As Dercolyte TM A115 is an α-pinenyl terpene resin derived from DRT. 9 As Oppaa TM 383 is a C9-modified and hydrogenated DCPD resin from Exxon Mobil. 10 The X50S uses 50% bis-triethoxysilylpropyltetrasulfide on a 50% N330 carbon black carrier from Evonik. 11 Mixed types of p-phenylenediamine 12 As Vulcuren TM 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane from Lanxess 13 sulfenamide type and guanidine type.

[0077] The rubber compositions listed in Table 1 above were tested in the treads of bus tires with the same construction. The results of these tests for rolling resistance and wet braking are shown in Table 2 below. In addition, the stiffness and wear properties of these compositions were tested, as also shown in Table 2.

[0078] Comparative Example 1 (not according to the invention) contains significantly more silica than the compositions tested in other experiments, which may explain the higher stiffness observed in Comparative Example 1 compared to the other tested examples. However, in this comparison, the rolling resistance of Comparative Example 1 was significantly worse than that of the other examples. Comparative Example 2 (also not according to the invention) has the same filler composition as Examples 1 and 3 of the invention, which may be one reason for the improved rolling resistance performance, but may also be a reason for the reduced wet braking performance. Meanwhile, compared to Comparative Example 1, the rubber stiffness of Comparative Example 2 and Examples 1 to 4 of the invention is reduced, which may affect the tire's ride and handling properties. Furthermore, the wear of Comparative Example 2 is significantly increased compared to the wear observed in Comparative Example 1.

[0079] All embodiments of the present invention exhibit significantly improved rolling resistance compared to Comparative Embodiment 1. While Comparative Embodiment 2 may have slightly better rolling resistance performance than Embodiments 3 and 4 of the present invention, the overall balance between rolling resistance, wet braking, and wear is improved in the embodiments of the present invention. Embodiments 1 and 2 of the present invention are particularly strong in terms of rolling resistance and wear. It is noteworthy that Embodiment 1 of the present invention shows a significant improvement in rolling resistance while having a very limited trade-off in wet performance and wear. Embodiment 3 of the present invention shows improved rolling resistance and wet braking performance simultaneously. In particular, the wet braking performance of Embodiments 1, 3, and 4 of the present invention is significantly better than the same performance of Comparative Embodiment 2. Furthermore, given the significantly improved rolling resistance, it is also advantageous to use one or more of the embodiments of the present invention in the bottom crown layer of the tire tread. In such cases, the slightly increased wear of some embodiments is not very relevant, and this also applies to wet braking performance. However, the preferred application of the embodiments of the present invention is in the radially outermost crown layer of the tire tread.

[0080] Table 2 Performance / Properties Comparative Example 1 Comparative Example 2 Embodiment 1 of the present invention Embodiment 2 of the present invention Embodiment 3 of the present invention Embodiment 4 of the present invention <![CDATA[Rolling resistance a > 100 103.6 110.9 106.8 102.7 102.7 <![CDATA[Wetland braking b > 100 96.7 99.1 95,7 103.8 99.4 <![CDATA[stiffness of rubber compound c > 1.4 1.2 1.2 1.2 1.1 1.2 <![CDATA[wear d > 128 136 129 126 136 132 a Compared to the tire test results, the normalization (higher is better) is compared to Comparative Example 1. b Compared to the tire test results, the normalization (higher is better) is compared to Comparative Example 1. cThe results of the rubber compound test for G' at 1% strain are shown. These results are based on ASTM D5289 and were obtained using the AlphaTechnologies RPA 2000™ Rubber Process Analyzer. d Drum wear test according to ASTM D5963 or equivalent.

Claims

1. A rubber composition comprising: Styrene-butadiene rubber of 70 phr to 90 phr, wherein the styrene-butadiene rubber comprises a first styrene-butadiene rubber with a glass transition temperature in the range of -20°C to -35°C and a bound styrene content in the range of 10% to 35%, and a second styrene-butadiene rubber with a glass transition temperature in the range of -51°C to -69°C and a bound styrene content in the range of 5% to 15%. 10 phr to 30 phr is selected from one or more members of natural rubber and synthetic polyisoprene rubber; 40 phr to 70 phr silica, wherein the BET surface area of ​​the silica is 190 m² 2 / g to 260 m 2 Within the range of / g; and At least one hydrocarbon resin with a pH of 15 to 40 phr, said hydrocarbon resin being selected from one or more of C9-modified CPD and C9-modified DCPD resins, wherein said resin is at least partially hydrogenated. The rubber composition comprises 40 phr to 65 phr of a first styrene-butadiene rubber and 25 phr to 50 phr of a second styrene-butadiene rubber, wherein the first styrene-butadiene rubber is at least 5 phr longer than the second styrene-butadiene rubber.

2. The rubber composition according to claim 1, characterized in that... The resin has a softening point in the range of 80°C to 150°C and a weight-average molecular weight in the range of 500 g / mol to 1000 g / mol.

3. The rubber composition according to claim 1 or 2, characterized in that... The resin has one or more of the following characteristics: Softening point in the range of 90℃ to 110℃; Weight-average molecular weight in the range of 500 g / mol to 800 g / mol; Glass transition temperature in the range of 30°C to 60°C.

4. The rubber composition according to claim 1 or 2, characterized in that... The resin has an aromatic proton content in the range of 5% to 15%.

5. The rubber composition according to claim 1 or 2, characterized in that... The rubber composition contains 50 phr to 65 phr of the silica.

6. The rubber composition according to claim 1 or 2, characterized in that... It also includes one or more of the following: Carbon black from 0.1 phr to 10 phr; Enhanced silanes from 4 phr to 8 phr; 4 phr to 7 phr capped mercaptosilanes; Liquid plasticizers from 0 phr to 10 phr.

7. The rubber composition according to claim 1 or 2, characterized in that... At least one of the first styrene-butadiene and the second styrene-butadiene comprises at least one functional group configured for coupling with the silica, optionally, the functional group being selected from one or more of polysiloxy, alkylsiloxy, aminoalkylsiloxy, tinamino, aminosiloxane and aminosilyl groups.

8. The rubber composition according to claim 1 or 2, characterized in that... Each styrene-butadiene rubber contains at least one functional group configured for coupling with silica; and optionally, one of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with an aminosilyl group, and the other of the first styrene-butadiene rubber and the second styrene-butadiene rubber is functionalized with an aminosiloxane group.

9. The rubber composition according to claim 1 or 2, characterized in that... The resin comprises 15 phr to 30 phr.

10. The rubber composition according to claim 1 or 2, characterized in that... The glass transition temperature of the rubber composition is in the range of -25°C to -15°C.

11. The rubber composition according to claim 1 or 2, characterized in that... The BET surface area of ​​the silica is 205 m². 2 / g to 260 m 2 Within the range of / g.

12. A tire (1) having a tread (10), wherein the tread (10) comprises a rubber composition according to any one of the preceding claims.

Images