Rubber compositions and tires

Abstract

Rubber compositions and tires are disclosed. A rubber composition and a tire comprising the rubber composition are disclosed. The rubber composition comprises 70 phr to 100 phr of at least one styrene-butadiene rubber; 0 phr to 30 phr of at least one additional diene-based rubber; 40 phr to 200 phr of at least one filler; at least 5 phr of aluminum hydroxide; and at least 0.5 phr of a rosin-based resin.

Description

Technical Field

[0001] This invention relates to rubber compositions. In particular, the rubber compositions can be used in tires, such as tire treads. Background Technology

[0002] Developing summer tires, especially high-performance summer tires, presents a challenge in further improving the balance between grip and rolling resistance, including dry and / or wet grip. Sufficient robustness is also expected in the tires.

[0003] Despite improvements made in this area over the past few decades, there remains significant room for further improvement in the balance of these properties. Summary of the Invention

[0004] The present invention relates to the rubber composition according to claim 1 and the tire according to claim 14.

[0005] The dependent claims relate to preferred embodiments of the invention.

[0006] One object of the present invention is to provide a rubber composition having an improved balance of grip and limited hysteresis.

[0007] Another object of the present invention is to provide an advanced rubber composition having sufficient tensile strength, good grip and limited hysteresis.

[0008] Another object of the present invention is to provide a rubber composition that allows for advanced wet grip and dry grip with limited hysteresis (or rolling resistance, respectively), optionally with sufficient tensile strength.

[0009] Therefore, in a first preferred aspect, the present invention relates to a rubber composition comprising at least one styrene-butadiene rubber of 70 phr to 100 phr, preferably solution-polymerized, at least one other diene-based rubber of 0 phr to 30 phr, at least one filler of 40 phr to 200 phr, at least 5 phr of aluminum hydroxide, and at least 0.5 phr of rosin-based resin.

[0010] This material combination has been found to result in a significant increase in grip. Driving and control properties under both wet and dry conditions have also been improved. Rolling resistance, or related parameters such as hysteresis, has been maintained at reasonable levels. The same applies to the tensile strength of this rubber composition.

[0011] In a preferred embodiment, the rubber composition comprises 5 phr to 80 phr of aluminum hydroxide, preferably 5 phr to 50 phr of aluminum hydroxide, or even more preferably 10 phr to 40 phr of aluminum hydroxide.

[0012] In a preferred embodiment, the rubber composition comprises 0.5 phr to 15 phr, preferably 0.5 phr to 10 phr, or more preferably 1 phr to 9 phr, or even more preferably 1 phr to 5 phr of rosin-based resin. In particular, it has been found that even surprisingly small amounts of rosin-based resin can significantly contribute to improved wet grip and / or wetland control performance. From a cost perspective, using such a small amount of rosin is also advantageous.

[0013] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin is based on one or more of rosin and dimer rosin.

[0014] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin has a softening point of 70°C-160°C.

[0015] The softening point of the resin is determined in this paper according to ASTM E28 or equivalent, and it may sometimes be referred to as the ring and ball softening point.

[0016] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin has an acid value of 130-180.

[0017] In a preferred embodiment, the rosin-based resin is rosin resin, which optionally has a softening point of 65°C-90°C, preferably 70°C-85°C, and preferably has an acid value of 140-180.

[0018] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin is a dimer rosin, optionally having a softening point of 130°C-160°C, preferably 140°C-150°C, and preferably having an acid value of 130-160, and even more preferably having an acid value of 140-150.

[0019] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin mainly comprises abietic acid. In the case of dimerization, it mainly comprises dimer abietic acid.

[0020] In a preferred embodiment, the rosin-based resin or the rosin acid-based resin is primarily based on abietic acid.

[0021] The terminology used above, based on rosin resin, can be replaced with rosin or rosin resin.

[0022] In a preferred embodiment, the rubber composition comprises 20 phr to 80 phr of resin or traction resin, such as a hydrocarbon resin.

[0023] In a preferred embodiment, the resin or hydrocarbon resin is selected from one or more of DCPD resin, CPD resin, terpene resin, C5 resin, C9 resin, coumarone-indene resin, styrene-α-methylstyrene, or combinations thereof. Optionally, these resins may be modified, particularly by aromatic / C9 modification, and / or fully or partially hydrogenated.

[0024] In a preferred embodiment, the resin is selected from one or more of DCPD resin, CPD resin, C5 resin, or combinations thereof. Preferably, the resin is a DCPD resin, and even more preferably, a C9-modified DCPD resin. This resin is optionally partially or completely hydrogenated.

[0025] In a preferred embodiment, the styrene-butadiene rubber is solution-polymerized styrene-butadiene rubber, and / or the diene-based rubber is one or more of synthetic polyisoprene and natural rubber.

[0026] In a preferred embodiment, the rubber composition comprises 70 phr to 90 phr of preferably solution-polymerized styrene-butadiene rubber and 10 phr to 30 phr of natural rubber and / or synthetic polyisoprene. This rubber matrix has been found to be the most preferred.

[0027] In a preferred embodiment, the styrene-butadiene rubber or solution-polymerized styrene-butadiene rubber is functionalized to couple to silica. For example, the rubber may contain one or more functional groups selected from amino, thioester, alkoxy, hydroxyl, and silyl groups.

[0028] In particular, the rubber may be functionalized with groups comprising at least one mercapto group and at least one alkoxy group (preferably terminal functionalized).

[0029] In a preferred embodiment, the filler mainly comprises silica.

[0030] In a preferred embodiment, the filler comprises less than 10 phr of carbon black (preferably less than 5 phr) and at least 40 phr of silica.

[0031] In a preferred embodiment, the rubber composition comprises at least 105 phr (preferably at least 115 phr) of silica and less than 10 phr (preferably less than 5 phr) of carbon black.

[0032] In a preferred embodiment, the styrene-butadiene rubber (which may be solution polymerized) has a glass transition temperature of -51°C to -86°C, preferably -61°C to -86°C.

[0033] In a preferred embodiment, the rubber composition comprises a resin or hydrocarbon resin (e.g., those mentioned herein) having a glass transition temperature of 35°C to 60°C at a temperature of 20 phr to 80 phr. In particular, it has been found that combinations of polymers with relatively low glass transition temperatures with resins with relatively high glass transition temperatures are desirable.

[0034] The glass transition temperature of the resins described herein was determined by differential scanning calorimetry (DSC) at a temperature increase rate of 10 °C per minute, in the form of the midpoint of the peak, according to ASTM D6604 or equivalent.

[0035] In a preferred embodiment, the rubber composition comprises 1 phr to 9 phr of vegetable oil having a glass transition temperature of -75°C to -100°C, preferably -75°C to -90°C.

[0036] In a preferred embodiment, the rubber composition primarily comprises silica as a filler, wherein the composition further comprises mercaptosilane (preferably a capped mercaptosilane, such as 3-(octanoylthio)-1-propyltriethoxysilane), preferably 1 phr to 20 phr, more preferably 10 phr to 20 phr.

[0037] In a preferred embodiment, the rubber composition further comprises α,ω-bis(N,N'-dialkylthiocarbamoyldithio)alkane, preferably 0.5 phr to 5 phr, or even more preferably 1 phr to 4 phr.

[0038] In a preferred embodiment, the α,ω-bis(N,N'-dialkylthiocarbamoyldithio)alkane is selected from 1,2-bis(N,N'-dibenzylthiocarbamoyldithio)ethane; 1,3-bis(N,N'-dibenzylthiocarbamoyldithio)propane; 1,4-bis(N,N'-dibenzylthiocarbamoyldithio)butane; 1,5-bis(N,N'-dibenzylthiocarbamoyldithio)butane; The compounds are: 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane; 1,7-bis(N,N'-dibenzylthiocarbamoyldithio)heptane; 1,8-bis(N,N'-dibenzylthiocarbamoyldithio)octane; 1,9-bis(N,N'-dibenzylthiocarbamoyldithio)nonane; and 1,10-bis(N,N'-dibenzylthiocarbamoyldithio)decane. Preferably, the α,ω-bis(N,N'-dialkylthiocarbamoyldithio)alkane is 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane. In particular, the inventors have found that this compound helps to further improve the abrasion properties of rubber compounds.

[0039] In a preferred embodiment, the aluminum hydroxide has one or more of the following: i) a D50 particle size of 0.2 μm-5 μm, and ii) a BET surface area of ​​1 m². 2 / g-20m 2 / g. In particular, larger particles may be less desirable.

[0040] Aluminum hydroxide particle size was determined using Zetasizer from Malvern. TM Nano S, measured using dynamic light scattering, based on ISO 22412 or equivalent. BET surface area of ​​aluminum hydroxide particles determined according to ISO 9277 or equivalent.

[0041] In a preferred embodiment, the BET surface area of ​​silica is 150 m². 2 / g to 220m 2 / g.

[0042] In a preferred embodiment, the rubber composition comprises at least one and / or another diene-based rubber. Representative synthetic polymers may be butadiene and its homologues and derivatives, such as homopolymers of methylbutadiene, dimethylbutadiene, and pentadiene, and copolymers, such as those formed from butadiene or its homologues or derivatives with other unsaturated monomers. The latter may include acetylene, such as vinylacetylene; olefins, such as isobutene, which copolymerizes 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 monomer (EPDM), and particularly ethylene / propylene / dicyclopentadiene terpolymers. Further examples of rubbers that may 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 rubbers, synthetic polyisoprene, polybutadiene, and SBR, including SSBR.

[0043] In a preferred embodiment, a combination of two or more rubbers is used, such as cis-1,4-polyisoprene rubber (natural or synthetic, but preferably natural), 3,4-polyisoprene rubber, styrene / isoprene / butadiene rubber, styrene / butadiene rubber derived from emulsion and solution polymerization, cis-1,4-polybutadiene rubber, and butadiene / acrylonitrile copolymers prepared by emulsion polymerization.

[0044] In a preferred embodiment, an emulsion polymerization-derived styrene-butadiene rubber (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 some cases, the ESBR will have a bound styrene content of 26% to 31%. ESBR prepared by emulsion polymerization can represent a copolymerization of styrene and 1,3-butadiene in the form of an aqueous emulsion. The bound styrene content can vary, for example, from 5% to 50%. In one aspect, the ESBR may also contain acrylonitrile to form a terpolymer rubber, such as ESBAR, with, for example, an amount of bound acrylonitrile of 2% to 30% by weight in the terpolymer. Styrene / butadiene / acrylonitrile copolymer rubbers prepared by emulsion polymerization containing 2% to 40% by weight of bound acrylonitrile in the copolymer can also be considered as diene-based rubbers.

[0045] In a preferred embodiment, a solution-polymerized styrene-butadiene rubber (SSBR) can be used. This SSBR may, for example, have a styrene content of 5-50%, preferably 9-36%, and most preferably 26-31%. SSBR can be conveniently prepared, for example, by anionic polymerization in an inert organic solvent. More specifically, SSBR can be synthesized using an organolithium compound as an initiator by copolymerizing styrene and 1,3-butadiene monomers in a hydrocarbon solvent. In another embodiment, the solution styrene-butadiene rubber is a tin-coupled polymer. In another embodiment, the SSBR is functionalized to improve compatibility with silica. Additionally, or alternatively, the SSBR is thiol-functionalized. This helps improve the stiffness and / or hysteretic behavior of the compound. Thus, for example, the SSBR can be a thiol-functionalized, tin-coupled solution polymer copolymer of butadiene and styrene.

[0046] In a preferred embodiment, synthetic or natural polyisoprene rubber is used. Synthetic cis-1,4-polyisoprene and natural rubber are well known to those skilled in the art of rubber. The cis-1,4-microstructure content is preferably at least 90%, and typically at least 95% or even higher.

[0047] In a preferred 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) of -95°C to -110°C. Suitable polybutadiene rubber is commercially available, such as 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, which are incorporated herein by reference.

[0048] When referred to herein, the glass transition temperature or Tg of an elastomer or elastomer composition means one or more glass transition temperatures of the corresponding elastomer or elastomer composition in its uncured state or, in the case of an elastomer composition, in its cured state. Such Tg, as used herein, is determined according to ASTM D3418 by means of the midpoint or inflection point of the glass transition-related stage of interest, such as using a differential scanning calorimeter (DSC) at a temperature change rate of 10 °C / min.

[0049] As used herein and in accordance with conventional practice, the term "phr" means "parts by weight of each material in 100 parts by weight of rubber or elastomer." Typically, using this convention, a rubber composition comprises 100 parts by weight of rubber / elastomer. A claimed composition may contain other rubbers / elastomers besides those expressly mentioned in the claims, provided that the phr value of the claimed rubber / elastomer is consistent with the claimed phr range, and the total amount of all rubbers / elastomers in the composition produces a total of 100 parts of rubber. In one example, the composition may further contain one or more additional diene-based rubbers, such as SBR, SSBR, ESBR, PBD / BR, NR, and / or synthetic polyisoprene, from 1 phr to 10 phr, optionally from 1 phr to 5 phr. In another example, the composition may contain less than 5 phr, preferably less than 3 phr, of additional diene-based rubber, or may contain substantially no such additional diene-based rubber. Unless otherwise stated, the terms "rubber compound," "composition," and "formulation" are used interchangeably herein.

[0050] In a preferred embodiment, the rubber composition may also contain one or more additional oils, particularly (additional) processing oils. Processing oils may be included in the rubber composition as increment oils typically used to fill elastomers. Processing oils may also be included in the rubber composition by adding oil directly during the rubber compounding process. The processing oils used may include both increment oils present in the elastomer and processing oils added during compounding. Suitable processing oils may include a variety of oils known in the art, including aromatic oils, alkane 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 having a polycyclic aromatic hydrocarbon (PCA) content of less than 3% by weight, as determined by the IP346 method. The procedure for the IP346 method can be found 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 (non-amined and non-epoxidized) vegetable oils that can be used include soybean oil, sunflower oil, low-erucic acid rapeseed oil (canola oil), corn oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, and safflower oil.

[0051] In a preferred embodiment, the rubber composition comprises silica. 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, for example, by acidifying soluble silicates such as sodium silicate. Such conventional silica may be characterized, for example, by having a BET surface area as measured using nitrogen. In one embodiment, the BET surface area may be 40 to 600 m² / g. In another embodiment, the BET surface area may be 50 to 300 m² / g. The BET surface area is determined herein according to ASTM D5604-96 or equivalent. Conventional silica may also be characterized by having a dibutyl phthalate (DBP) absorbance value of 100 cm³ / 100 g to 400 cm³ / 100 g, or 150 cm³ / 100 g to 300 cm³ / 100 g, which may be suitably determined according to ASTM D 2414 or equivalent. Various commercially available silicas may be used, such as, for example only and without limitation, silicas that are commercially available from PPG Industries under the trademark Hi-Sil, using names such as 210, 315G, EZ160G, etc.; silicas that are available from Solvay, having names such as ZeoSil 1165 MP and ZeoSil Premium 200 MP; and silicas that are available from Evonik AG, having names such as VN2 and Ultrasil 6000 GR, 9100GR, etc.

[0052] In a preferred embodiment, the rubber composition comprises pre-silanized and precipitated silica, which may, for example, have a silica content of 130 μm. 2 / g to 210m 2 / g, choose any 130m 2 / g to 150m 2 / g and / or 190m 2 / g to 210m 2 / g, or even 195m 2 / g to 205m 2 / g of CTAB adsorption surface area. The CTAB (cetyltrimethylammonium bromide) method for determining the surface area of ​​silica (ASTM D6845) is known to those skilled in the art.

[0053] In a preferred embodiment, surface-modified precipitated silica is used, which has been treated with at least one silane or silazane prior to its addition to the rubber composition. Suitable surface modifiers include, but are not limited to, alkylsilanes, alkoxysilanes, organoalkoxysilyl polysulfides, organothiol alkoxysilanes, and hexamethyldisilazane.

[0054] Optional silica dispersing agents may be present in amounts from 0.1 wt% to 25 wt% based on the weight of silica, wherein amounts from 0.5 wt% to 20 wt% based on the weight of silica are suitable, and amounts from 1 wt% to 15 wt% are also suitable. Various pretreated precipitated silica are described in U.S. Patents 4,704,414, 6,123,762, and 6,573,324. The teachings of U.S. Patents 4,704,414, 6,123,762, and 6,573,324 are incorporated herein by reference.

[0055] Examples of pretreated silica (i.e., silica that has been pre-surface-treated with silanes) suitable for use in the practice of this invention include Ciptane® 255 LD and Ciptane® LP (PPG Industries) silica that has been pretreated with mercaptosilanes, and Coupsil® 8113 (Degussa) and Coupsil® 6508, reaction products of organosilane bis(triethoxysilylpropyl) polysulfides (Si69) with Ultrasil® VN3 silica; Agilon® 400 silica from PPG Industries; Agilon® 454 silica from PPG Industries; and Agilon® 458 silica from PPG Industries. Some representative examples of preferred pre-silanized precipitated silica include Agilon® 400, Agilon® 454, and Agilon® 458 from PPG Industries.

[0056] A representative silica coupling agent (silica coupling agent) having a portion that reacts with the pre-silanized precipitated silica and the hydroxyl groups on the precipitated silica, and another portion that interacts with the elastomer, may comprise, for example, the following: (A) a bis(3-trialkoxysilylalkyl) polysulfide containing an average of 2-4, or 2-2.6, or 3.2-3.8 sulfur atoms in its connecting bridges; or (B) an alkoxyorgano-mercaptosilane; or (C) a combination thereof. Representative examples of such bis(3-trialkoxysilylalkyl) polysulfides include bis(3-triethoxysilylpropyl) polysulfides. As described, for pre-silanized precipitated silica, the silica coupling agent may desirablely be an alkoxyorgano-mercaptosilane. For non-pre-silanized precipitated silica, the silica coupling agent may desirablely comprise a bis(3-triethoxysilylpropyl) polysulfide.

[0057] In a preferred embodiment, the rubber composition does not include the addition of a silica coupling agent to the rubber composition (thus it does not contain a silica coupling agent).

[0058] In a preferred embodiment, the rubber composition may contain additional silica coupling agents added to the rubber composition, particularly bis(3-triethoxysilylpropyl) polysulfides containing an average of 2-4 sulfur atoms linked in their polysulfide bridges, in combination with additional precipitated silica (non-presilanized precipitated silica) added to the rubber composition, wherein the ratio of presilanized precipitated silica to the precipitated silica is preferably at least 8 / 1 or at least 10 / 1.

[0059] In a preferred embodiment, the rubber composition may comprise carbon black. Representative examples of such carbon black 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 absorption of 9 g / kg to 145 g / kg and a 34 cm⁻¹ iodine content. 3 / 100g-150 cm 3 The DBP value per 100g. Iodine absorption value can be suitably determined according to ASTM D1510 or equivalent. In this document, carbon black is commonly used as a conventional filler in amounts of 1-100 phr. However, in a preferred embodiment, the composition contains up to 10 phr of carbon black, preferably up to 5 phr, as preferred embodiments involve high silica compounds and their property improvements.

[0060] Other fillers can be used in rubber compositions, including particulate fillers, including ultra-high molecular weight polyethylene (UHMWPE), crosslinked particulate polymer gels, including those disclosed in U.S. Patents 6,242,534, 6,207,757, 6,133,364, 6,372,857, 5,395,891, or 6,127,488, and plasticized starch composite fillers, including those disclosed in U.S. Patent 5,672,639. Meta-isobutadiene may also be used. These other fillers can be used in amounts from 1 phr to 30 phr; however, it is preferred herein to use them in amounts less than 5 phr.

[0061] In a preferred embodiment, the rubber composition may contain a conventional sulfur-containing organosilicon compound or a silane. Examples of suitable sulfur-containing organosilicon compounds have the following formula:

[0062] I

[0063] Where Z is selected from

[0064]

[0065] Where R 1 It is an alkyl, cyclohexyl, 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, for formula I, Z can be...

[0066]

[0067] Where R 2 Alk is an alkoxy group with 2 to 4 carbon atoms or 2 carbon atoms; Alk is a divalent hydrocarbon with 2 to 4 carbon atoms or 3 carbon atoms, and n is an integer from 2 to 5 or 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 one embodiment, the sulfur-containing organosilicon compound includes 3-(octanoylthio)-1-propyltriethoxysilane, CH3(CH2)6C(=O)-S-CH2CH2CH2Si(OCH2CH3)3, which is an NXT TM Available commercially 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 sulfur-containing organosilicon compound in the rubber composition may vary depending on the levels of other additives used. Generally, the amount of the compound can be from 0.5 phr to 20 phr.

[0068] In a preferred embodiment, the rubber composition contains a cobalt salt of less than 0.1 phr or a cobalt salt of 0 phr.

[0069] Those skilled in the art will readily understand that rubber compositions can be compounded using methods commonly known in the field of rubber compounding, such as mixing various sulfur-curable component rubbers with various commonly used additive materials, including, for example, sulfur donors, curing aids such as activators and scorch inhibitors, and processing additives such as oils, resins including tackifying resins and plasticizers, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants, anti-ozone agents, and plasticizers. As is known to those skilled in the art, the above-mentioned additives are selected according to the intended use of the sulfur-curable and sulfur-curable materials (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-curing agent is elemental sulfur. The sulfur-curing agent may be used, for example, in amounts from 0.5 phr to 8 phr, or alternatively from 1.5 phr to 6 phr. Typical amounts of tackifier resins, if used, include, for example, 0.5 phr to 10 phr, typically 1 phr to 5 phr. Typical amounts of processing aids, if used, include, for example, 1 phr to 50 phr (this may include, in particular, oils). Typical amounts of antioxidants, if used, may include, for example, 1 phr to 5 phr. Representative antioxidants may be, for example, diphenyl-p-phenylenediamine and others, such as those disclosed, for example, in The Vanderbilt Rubber Handbook (1978), pp. 344-346. Typical amounts of anti-ozone agents, if used, may include, for example, 1 phr to 5 phr. Typical amounts of fatty acids, if used, which may include stearic acid, may include, for example, 0.5 phr to 3 phr. Typical amounts of waxes, if used, may be employed at a level of 1 phr to 5 phr. Microcrystalline waxes are commonly used. Typical amounts of plasticizers, if used, are typically 0.1 phr to 1 phr. Typical plasticizers can be, for example, pentachlorothiophenol and / or dibenzoylamino diphenyl disulfide.

[0070] Accelerators are preferred, but not necessarily 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 0.5 phr to 4 phr, alternatively 0.8 phr to 1.5 phr. In another embodiment, a combination of a primary accelerator and a secondary accelerator can be used, wherein the secondary accelerator is used in a smaller amount, e.g., 0.05 phr to 3 phr, to activate and improve the properties of the vulcanized rubber. Such 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 one 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. Vulcanization scorch inhibitors 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 xanthate esters / salts. In one embodiment, the primary accelerator is a sulfenamide. If an auxiliary accelerator is used, it may be, for example, a guanidine, a dithiocarbamate, or a thiuram compound. Suitable guanidines include diphenylguanidine, etc. Suitable thiurams include tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetraphenylthiuram disulfide.

[0071] 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. Final curing agents, including vulcanizing agents, are typically mixed in a final stage, often referred to as a “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. In one embodiment, the rubber composition may undergo a thermomechanical mixing step. A 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 of 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.

[0072] In a preferred embodiment, a tire is provided having a tread comprising a rubber composition according to the invention.

[0073] In a preferred embodiment, the tire has a tread with one or more tread cap layers, wherein the rubber composition is in one or more of the two radially outermost tread cap layers, preferably in the radially outermost tread cap layer.

[0074] In a preferred embodiment, the rubber composition according to the invention is used in the tread crown layer radially inside the radially outermost tread crown layer. Preferably, the rubber composition is not in the radially outermost tread crown layer. In such an embodiment, the radially outermost tread crown layer does not contain the rubber composition according to the invention. Instead, the rubber composition of the tread crown layer radially below the radially outermost tread crown layer contains the rubber composition according to the invention (or one or more of the embodiments thereof). This arrangement or configuration helps maintain a similar level of grip, particularly wet grip, when the first tread crown layer wears and the radial rib or block height of the tread has decreased. The loss of tread height can then be at least partially compensated for by the improved grip of the rubber composition according to the invention.

[0075] The rubber composition can also be used in power transmission belts, hoses, tracks, air sleeves and conveyor belts.

[0076] In a preferred embodiment, the rubber composition according to the invention is used in a tire assembly selected from the tread, shear band, rubber spokes, tread undertread, sidewall, triangular core, bead core wrap, heel reinforcement, bead wrap, carcass, and belt layer.

[0077] The vulcanization of the tires of the present invention, preferably pneumatic tires, can be carried out at a conventional temperature of 100°C to 200°C. In one embodiment, vulcanization is carried out at a temperature of 110°C to 180°C. Any commonly used vulcanization method can be used, such as heating in a press or mold, or heating with superheated steam or hot air. However, it is generally preferred that the tires of the present invention be cured at a temperature of 132°C to 166°C. More typically, the tires of the present invention are cured at a temperature of 143°C to 154°C. Such tires can be manufactured, formed, molded, and cured by various methods known and obvious to those skilled in the art. Attached Figure Description

[0078] The structure, operation, and advantages of the invention will become more apparent when the following description is taken in conjunction with the accompanying drawings, wherein... Figure 1 This is a schematic cross-section of a tire comprising a rubber assembly having a rubber composition according to an embodiment of the present invention. Detailed Implementation

[0079] Figure 1This is a schematic cross-section of a tire 1 according to an embodiment of the present invention. The tire 1 has multiple tire components, such as a tread 10, a liner 13, a belt including four belt plies 11, a carcass plies 9, two sidewalls 2 and two bead areas 3, a bead filler apex 5, and a bead 4. The exemplary tire 1 is suitable for mounting, for example, on the rim of a vehicle, such as a truck or passenger car. Figure 1 As shown, the belt ply 11 may be covered by an overlay ply 12 and / or may include one or more cushioning layers. The carcass ply 9 includes a pair of axially opposed end portions 6, each engaging with each of the bead 4. Each axial end portion 6 of the carcass ply 9 may be reversed and wrapped around each bead 4 to a position to anchor the axial end portion 6. The reversed portion 6 of the carcass ply 9 may engage the axially outer surfaces of the two bead core wraps 8 and the axially inner surfaces of the two heel reinforcement layers 7 (which are also considered tire assemblies). Figure 1 As shown, the exemplary tread 10 may have circumferential grooves 20, each groove 20 substantially defining a U-shaped opening in the tread 10. The main portion of the tread 10 may be formed from one or more tread compounds. Furthermore, the grooves 20, particularly the bottom and / or sidewalls of the grooves 20, may be reinforced by a rubber compound having a higher hardness and / or stiffness than the remaining tread compound. Such reinforcement may be referred to herein as a groove reinforcement.

[0080] 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 an overlay 12, but these and other components are not mandatory to the invention. The reverse-wrapped end of the carcass ply 9 is also not essential to the invention, and may pass through and terminate on the opposite side of the bead area 3 at the axially inner side of the bead 4 rather than the axially outer side of the bead 4. The tire may also have, for example, a different number of tread grooves 20, such as less than four tread grooves.

[0081] The rubber composition according to a preferred embodiment of the present invention is used for a tread or tread layer in contact with the ground or road. In one embodiment, the tread 10 of tire 1 or another tire comprises a rubber composition according to embodiments of the present invention as determined in Table 1 below. Comparative Examples 1-4 in Table 1 contain different amounts of aluminum hydroxide but have the same rubber matrix. The embodiments of the present invention contain appropriate amounts of aluminum hydroxide and additional rosin-based resin.

[0082]

[0083] 1 As a Sprintan from Trinseo TMSLR 3402 has a Tg of -62°C and mercapto-alkoxysilane functionality.

[0084] 2 Natural rubber

[0085] 3 As Zeosil TM 1165 MP, with 160 g / m 2 BET surface area

[0086] 4 As an Oppera from Exxon Mobil TM 383

[0087] 5 rosin

[0088] 6 Al(OH)3, has 6m 2 The BET surface area is 1.0 μm, d50 is 2.4 μm, d10 is 0.5 μm, and the density is 2.4 g / cm³.

[0089] 7 Sunflower oil has a Tg of approximately -80°C.

[0090] 8 As an NXT from Momentive TM

[0091] 9 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane containing 10% by weight of oil and carbon black

[0092] 10 Including dihydroquinoline and phenylenediamine

[0093] 11 50% bis(triethoxysilylpropyl)tetrasulfide and 50% carbon black, such as the X50S from Evonik.

[0094] 12 diphenylguanidine

[0095] 13 N-tert-butyl-2-benzothiazole sulfenamide

[0096] Table 2 shows the test data obtained from the comparative examples and embodiments of the present invention listed in Table 1 above. As is evident from the results below, the wet grip of the embodiments of the present invention is significantly improved by the addition of a relatively small amount of rosin resin. Wet grip is also significantly improved compared to Comparative Example 1 (without aluminum hydroxide) and also compared to Comparative Example 2, which contains the same amount of aluminum hydroxide as the embodiments of the present invention. Dry grip is also surprisingly significantly improved, superior to Comparative Examples 1 and 3. Dry braking remains substantially the same. Tensile strength remains at a good level despite the addition of aluminum hydroxide. In summary, the non-limiting embodiments of the present invention provide an advanced balance of properties.

[0097]

[0098] a Laboratory tests were conducted, and the results were normalized to Comparative Example 1, based on the determination of transmissible frictional forces on a linear friction tester.

[0099] b Tire test results were normalized to Comparative Example 1.

[0100] c Tire test results were normalized to Comparative Example 1.

[0101] d Tire test results were normalized to Comparative Example 1.

[0102] e Laboratory tests, where tensile strength is the breaking stress, are conducted using ring specimens according to ASTM D412.

Claims

1. A rubber composition comprising: At least one styrene-butadiene rubber with a phr of 70 phr to 90 phr; At least one other diene-based rubber with a 10 phr to 30 phr; At least one filler comprising 40 phr to 200 phr, wherein the filler comprises at least 105 phr of silica and less than 10 phr of carbon black; Aluminum hydroxide from 10 phr to 40 phr; 1 phr to 9 phr of rosin-based resins or rosin acid-based resins; as well as Traction resin from 20 phr to 80 phr.

2. The rubber composition according to claim 1, wherein the rosin-based resin or the rosin acid-based resin is based on one or more of rosin and dimer rosin.

3. The rubber composition according to claim 1, wherein the traction resin is selected from at least one of DCPD resin, CPD resin, terpene resin, C5 resin, C9 resin, coumarone indene resin, styrene-α-methylstyrene resin, or combinations thereof.

4. The rubber composition according to claim 1, wherein the styrene-butadiene rubber is solution-polymerized styrene-butadiene rubber, and wherein the diene-based rubber is one or more of synthetic polyisoprene and natural rubber.

5. The rubber composition according to claim 1, wherein the styrene-butadiene rubber is functionalized to couple to silica.

6. The rubber composition of claim 1, wherein the silica has a BET surface area of 150 m 2 / g to 220 m 2 / g.

7. The rubber composition according to claim 1, wherein the styrene-butadiene rubber has a glass transition temperature of -51°C to -86°C.

8. The rubber composition according to claim 1, wherein the glass transition temperature of the traction resin is 35°C to 60°C.

9. The rubber composition according to claim 1, wherein the rubber composition comprises 1 phr to 9 phr of vegetable oil, the vegetable oil having a glass transition temperature of -75°C to -100°C.

10. The rubber composition according to claim 1, wherein the rubber composition mainly comprises silica as a filler, and wherein the composition further comprises mercaptosilane.

11. The rubber composition according to claim 1, wherein the rubber composition further comprises 10 phr to 20 phr mercaptosilane.

12. The rubber composition of claim 1, wherein the aluminum hydroxide has one or more of: i) a D50 particle size of 0.2 pm - 5 pm, ii) a BET surface area of 1 m 2 / g - 20 m 2 / g.

13. A tire comprising a rubber composition according to any one of the preceding claims.

14. The tire of claim 13, comprising a tread using a radially outermost tread crown layer containing the rubber composition.

Images