JP2023051879A - Rubber composition and tire - Google Patents

Abstract

To provide a rubber composition, and a tire formed from the rubber composition.SOLUTION: A rubber composition contains 70-100 phr of at least one styrene-butadiene rubber, 0-30 phr of at least one diene-based rubber, 40-200 phr of at least one filler, at least 5 phr of an aluminum hydroxide, and at least one hydrocarbon resin among one or more selected from an aluminum hydroxide, a DCPD resin, a CPD resin and a C5 resin.SELECTED DRAWING: None

Description

The present invention relates to rubber compositions and tires. The rubber composition of the present invention can be used in tires such as tire treads.

In the development of summer tires, especially low rolling resistance summer tires, it is a challenge to further improve the balance between grip, including dry grip and wet grip, and rolling resistance. At the same time, tires must be robust.
Although many improvements have been made in this area over the last few decades, there is still considerable room for improvement in the balance of properties described above.

One object of the present invention is to provide a rubber composition having a favorable balance of improved grip and limited hysteresis.
Another object of the present invention is to provide a rubber composition having sufficient tensile strength, good grip properties and limited hysteresis.
Yet another object of the present invention is to provide a rubber composition that provides good wet and dry grip, with limited hysteresis (or rolling resistance, respectively), and optionally with sufficient tensile strength.

The present invention relates to a rubber composition according to claim 1 and a tire according to claim 9.
The dependent claims refer to preferred embodiments of the invention.

In a first preferred embodiment of the invention, from 70 phr to 100 phr of at least one styrene-butadiene rubber, from 0 phr to 30 phr of at least one (further) diene-based rubber, from 40 phr to 200 phr of at least one filler, at least A rubber composition is disclosed comprising 5 phr of aluminum hydroxide and at least one (hydrocarbon) resin selected from one or more of dicyclopentadiene (DCPD) resin, cyclopentadiene (CPD) resin and C5 resin. there is

It has been found that the combination of aluminum hydroxide and the claimed resin surprisingly improves the balance between rolling resistance and wet grip. Furthermore, tread wear can be further improved. Such combinations can be of particular interest for low rolling resistance tires, for example low rolling resistance passenger car tires.
In a preferred embodiment of the invention, the rubber composition comprises 5-80 phr aluminum hydroxide, preferably 10-40 phr aluminum hydroxide.

In a preferred embodiment of the invention, the rubber composition comprises 15 phr to 80 phr resin, preferably 15 phr to 40 phr, more preferably 15 phr to 35 phr resin.
In a preferred embodiment of the invention the resin is an at least partially hydrogenated resin, preferably a fully hydrogenated resin.
In preferred embodiments of the invention, the resin is aromatic or C9 modified.
In a preferred embodiment of the invention, the resin is a hydrogenated and C9 modified resin, preferably a hydrogenated and C9 modified DCPD or CPD resin.
In preferred embodiments of the invention, the resin has a glass transition temperature within the range of 35°C to 65°C. Preferably, the resin has a relatively high, but still limited, glass transition temperature.

As used herein, the glass transition temperature of a resin is determined as the peak midpoint by differential scanning calorimeter (DSC) at a heating rate of 10° C. per minute according to ASTM D6604 or a method equivalent thereto.

In preferred embodiments of the invention, the resin is selected from one or more of C5 resins, CPD resins, DCPD resins, C9 modified C5 resins, C9 modified CPD resins, and C9 modified DCPD resins. Optionally, these resins may be partially or fully hydrogenated.
In preferred embodiments of the invention, the resin is selected from one or more of C9-modified CPD resins and C9-modified DCPD resins.

In a preferred embodiment of the invention, the resin has an aromatic proton content within the range of 5% to 15%, preferably within the range of 8% to 12%. This content can be determined, for example, by NMR, as known by those skilled in the art.

In preferred embodiments of the present invention, the resin has a softening point within the range of 88°C to 110°C, determined herein according to ASTM E28, or equivalent, which is sometimes referred to as the ring and ball softening point It is sometimes called

In a preferred embodiment of the invention, the resin has a weight average molecular weight Mw in the range of 500 g/mol to 800 g/mol as determined by gel permeation chromatography (GPC) using polystyrene calibration standards according to ASTM 5296-11 or equivalent. have

In a preferred embodiment of the invention, the rubber composition has a glass transition temperature within the range of -25°C to -15°C, determined as described herein below.

In a preferred embodiment of the invention, at least one styrene-butadiene rubber is a solution-polymerized styrene-butadiene rubber; and/or the diene-based rubber is polyisoprene, preferably one or two of synthetic polyisoprene and natural rubber. It is characterized by being more than seed.

In a preferred embodiment of the present invention, the rubber composition comprises i) a first styrene-butadiene rubber (preferably solution polymerized) having a glass transition temperature within the range of -51°C to -86°C, and ii) It is composed of a second styrene-butadiene rubber (preferably solution polymerized) having a glass transition temperature in the range of -45°C. Preferably, at least one (or both) of said first and second styrene-butadiene rubbers are functionalized for coupling with fillers (such as carbon black or silica), especially silica.

In a preferred embodiment of the invention, the rubber composition comprises from 40 phr to 60 phr of the first styrene butadiene rubber and from 30 phr to 50 phr of the second styrene butadiene rubber.

In a preferred embodiment of the invention, the first and second styrene-butadiene rubbers contain at least one functional group configured for coupling with silica.

In a preferred embodiment of the present invention, at least one of the first and second styrene-butadiene rubbers contains at least one functional group configured for coupling with silica, said functional group being siloxy, alkoxy, One or more selected from amino, alkylsiloxy, tinamino, aminosiloxane and aminosilane and thiol groups.

In a preferred embodiment of the invention, one styrene-butadiene rubber of the first and second styrene-butadiene rubbers is functionalized with aminosilane groups and another one of the first and second styrene-butadiene rubbers is aminosiloxane. functionalized with a group.

In a preferred embodiment of the invention, one of the first and second styrene-butadiene rubbers is functionalized with at least one thiol group and another one of the first and second styrene-butadiene rubbers is an aminosilane or an amino Functionalized with at least one of the siloxane groups. Preferably, the styrene-butadiene rubber with the lower Tg is functionalized with thiol groups.

In a preferred embodiment of the invention, the first styrene butadiene rubber has a glass transition temperature in the range of -20°C to -35°C and the second styrene butadiene rubber has a glass transition temperature in the range of -55°C to -69°C. It has a glass transition temperature within

In a preferred embodiment of the present invention, the filler is mainly composed of silica.
In a preferred embodiment of the invention, the filler comprises less than 10 phr carbon black, preferably less than 5 phr carbon black, and at least 40 phr silica.
In a preferred embodiment of the invention, the rubber composition comprises up to 85 phr silica. A limited amount of silica or filler is particularly desirable for low rolling resistance applications, or ultra-low rolling resistance applications.

In preferred embodiments of the invention, the aluminum hydroxide has one or more of the following characteristics. (i) D50 particle size in the range of 0.2 μm to 5 μm, and (ii) BET surface area in the range of 1 m ² /g to 20 m ² /g.
The aluminum hydroxide particle diameter is determined using a Malvern Zetasizer ^™ Nano S using dynamic light scattering according to ISO 22412 or equivalent.
The BET specific surface area of aluminum hydroxide particles is determined according to ISO 9277 or its equivalent.

In preferred embodiments of the invention, the silica has a BET surface area within the range of 150 m ² /g to 220 m ² /g. In particular, high surface area silica is preferred herein.

In a preferred embodiment of the present invention, the rubber composition comprises, apart from said hydrocarbon resin, one or more of (i) from 0 phr to less than 5 phr of a further resin; and (ii) from 0 phr to less than 5 phr of an oil. . Therefore, in such preferred embodiments, the amount of additional plasticizer and/or resin or oil is limited. Preferably, the oil content is less than 1 phr or 0 phr.

In a preferred embodiment of the invention, the rubber may be functionalized (preferably terminally functionalized) with groups consisting of at least one thiol group and at least one alkoxy group.

In a preferred embodiment of the invention, the rubber composition comprises 1 phr to 4 phr of a vegetable oil having a glass transition temperature in the range of -75°C to -100°C, preferably in the range of -75°C to -90°C. .

The glass transition temperature of the oil is determined as the peak midpoint by differential scanning calorimeter (DSC) at a heating rate of 10°C per minute according to ASTM E1356 or an equivalent method.

In a preferred embodiment of the present invention, the rubber composition is based on silica as filler and the composition contains mercaptosilane (preferably 3-(octanoylthio)-1- blocked mercaptosilanes such as propyltriethoxysilane).

In a preferred embodiment of the present invention, the rubber composition further comprises an α,ω-bis(N,N'-dihydrocarbylthiocarbamoyldithio)alkane, preferably within the range of 0.5 phr to 5 phr, more preferably 1 phr to 4 phr. include.

In a preferred embodiment of the invention, the α,ω-bis(N,N′-dihydrocarbylthiocarbamoyldithio)alkane is 1,2-bis(N,N′-dibenzylthiocarbamoyldithio)ethane; Bis(N,N'-dibenzylthiocarbamoyldithio)propane; 1,4-bis(N,N'-dibenzylthiocarbamoyldithio)butane; 1,5-bis(N,N'-dibenzylthiocarbamoyldithio) ) pentane; 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane; 1,7-bis(N,N'-dibenzylto-dibenzylthiocarbamoyldithio)heptane; 1,8-bis(N ,N′-dibenzylthiocarbamoyldithio)octane; 1,9-bis(N,N′-dibenzylthiocarbamoyldithio)nonane; and 1,10-bis(N,N′-dibenzylthiocarbamoyldithio)decane. selected from the group consisting of Preferably, the α,ω-bis(N,N'-dihydrocarbylthiocarbamoyldithio)alkane is 1,6-bis(N,N'-dibenzylthiocarbamoyldithio)hexane.

In a preferred embodiment of the invention, the rubber composition consists of 0.5 phr to 15 phr, preferably 0.5 to 10 phr, more preferably 1 phr to 9 phr, or even more preferably 1 phr to 5 phr of the rosin base resin. In particular, it has been found that even a surprisingly small amount of rosin-based resin can significantly support improved wet grip and/or wet handling performance. The use of such small amounts of rosin is also positive from a cost point of view.

In preferred embodiments of the present invention, the rosin-based resin (or rosin acid-based resin) is based on one or more of gum rosin and dimerized gum rosin.

In a preferred embodiment of the present invention, the rosin-based resin has a softening point within the range of 70°C to 160°C.
As used herein, the softening point of a resin is determined according to ASTM E28, or equivalent, and is sometimes referred to as the ring and ball softening point.

In a preferred embodiment of the invention, the rosin-based resin has an acid value within the range of 130-180.

In a preferred embodiment of the invention, the rosin-based resin is a gum rosin, optionally with a softening point within the range of 65°C to 90°C, preferably 70°C to 85°C, preferably within the range of 140 to 180°C. have value.

In a preferred embodiment of the invention, the rosin-based resin is a dimerized gum rosin, optionally having a softening point within the range of 130°C to 160°C, preferably 140°C to 150°C, preferably 130 to 160, and even It preferably has an acid number in the range of 140-150.

In a preferred embodiment of the present invention, the rosin resin is mainly composed of abietic acid. When dimerized, the main component is dimerized abietic acid.

In a preferred embodiment of the present invention, the rosin-based resin contains abietic acid as a main component.

Optionally, the term rosin-based resin can be replaced with rosin or rosin resin.

In a preferred embodiment of the invention, the rubber composition contains from 20 phr to 80 phr of resin (or hydrocarbon resin).

In a preferred embodiment of the invention, the rubber composition may comprise at least one and/or one additional diene-based rubber. Representative synthetic polymers include butadiene and its homologs and derivatives, such as the homopolymerization products of methylbutadiene, dimethylbutadiene and pentadiene, and polymers formed from butadiene or its homologs or derivatives and other unsaturated monomers. It can be a copolymer. Among the latter are acetylenes, such as vinyl acetylene; olefins, such as isobutylene, which copolymerizes with isoprene to form butyl rubber; vinyl compounds, such as acrylic acid, acrylonitrile (which polymerize with butadiene to form NBR); methacrylic acid and styrene (the latter polymerized with butadiene to form SBR), as well as vinyl esters and various unsaturated aldehydes, ketones and ethers such as acrolein, methyl isopropenyl ketone, vinyl ethyl ether, and the like. Specific examples of synthetic rubber include neoprene (polychloroprene), polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, chlorobutyl rubber and bromobutyl rubber. halobutyl 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), especially ethylene/propylene/ Dicyclopentadiene terpolymers are included. Additional examples of rubbers that can be used include alkoxy-silyl end-functionalized solution polymerized polymers (SBR, PBR, IBR and SIBR), silicon-bonded and tin-bonded star-branched polymers. Preferred rubbers or elastomers may generally be natural rubber, synthetic polyisoprene, polybutadiene, and SBR, including SSBR.

In a preferred embodiment of the invention, the composition contains less than 5 phr of natural rubber and/or polyisoprene, or is essentially free/free of natural rubber and/or polyisoprene.

Combinations of two or more rubbers include cis-1,4-polyisoprene rubber (natural or synthetic, although natural is preferred), 3,4-polyisoprene rubber, styrene/isoprene/butadiene rubber, emulsion and solution polymerization derived rubbers. Styrene/butadiene rubber, cis-1,4-polybutadiene rubber, butadiene/acrylonitrile copolymer prepared by emulsion polymerization, and the like are preferred.

In a preferred embodiment of the invention, an emulsion polymerization derived styrene-butadiene rubber (ESBR) having a bound styrene content of 20 to 28 percent or, in some applications, a moderate to relatively high bound styrene content, i.e., 30 An ESBR with a bound styrene content of ˜45 percent can be used. Often the ESBR will have a bound styrene content in the range of 26-31 percent. ESBR prepared by emulsion polymerization may mean that styrene and 1,3-butadiene are copolymerized as an aqueous emulsion. Such are well known to those skilled in such art. The bound styrene content can vary, for example, from 5-50%. In one embodiment, the ESBR may also contain acrylonitrile as an ESBAR, eg, in an amount of 2 to 30 weight percent bound acrylonitrile in the terpolymer to form a terpolymer rubber. Emulsion polymerization prepared styrene/butadiene/acrylonitrile copolymer rubbers containing 2 to 40 weight percent bound acrylonitrile in the copolymer may also be contemplated as diene-based rubbers.

In a preferred embodiment of the invention, solution polymerization prepared SBR (SSBR) is used. Such SSBR can have, for example, a bound styrene content in the range 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 by copolymerizing styrene and 1,3-butadiene monomers in a hydrocarbon solvent utilizing an organolithium compound as an initiator. In yet another embodiment, the solution styrene butadiene rubber is a tin-bonded polymer. In yet another embodiment, the SSBR is functionalized to improve compatibility with silica. Additionally or alternatively, the SSBR is thio-functionalized. This helps improve the stiffness of the compound and/or its hysteresis behavior. Thus, for example, the SSBR may be a thio-functionalized tin-bonded solution polymerized copolymer of butadiene and styrene.

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

In one embodiment, cis-1,4-polybutadiene rubber (BR or PBD) is also used. Suitable polybutadiene rubbers can be prepared, for example, by organic solution polymerization of 1,3-butadiene. BR can be conveniently characterized, for example, by having a cis-1,4-microstructure content (“high cis” content) of at least 90% and a glass transition temperature (Tg) of -95 to -110°C. Suitable high cis-polybutadiene rubbers are commercially available from The Goodyear Tire and Rubber Company, Budene® 1207, Budene® 1208, Budene® 1223, or Budene ( (registered trademark) 1280 and the like. These high cis-1,4-polybutadiene rubbers are described, for example, in US Pat. No. 5,698,643 and US Pat. It can be synthesized using a nickel catalyst system that includes a mixture of (1) an organonickel compound, (2) an organoaluminum compound, and (3) a fluorine-containing compound.

The glass transition temperature, or Tg, of an elastomer or elastomer/rubber composition, as referred to herein, refers to the glass transition temperature of the respective elastomer, or in the case of an elastomer composition, in the uncured or cured state. .

Tg is determined by the midpoint or point of inflection of the steps observed during the glass transition, measured at a rate of temperature change of 10°C per minute using a differential scanning calorimeter (DSC) according to ASTM D3418. be.

As used herein, the term "phr" means, in accordance with conventional practice, "parts by weight of the respective material per 100 parts by weight of rubber or elastomer". Generally, using this convention, the rubber composition contains 100 parts by weight rubber/elastomer. The claimed composition is such that the phr value of the claimed rubber/elastomer is in accordance with the claimed phr range and the total amount of all rubbers/elastomers in the composition is 100 parts. The claims may include rubbers/elastomers other than those explicitly recited in the claims, provided that they are attributed to the rubber of the invention. In one example, the composition further comprises from 1 phr to 10 phr, optionally from 1 to 5 phr, of one or more additional diene-based rubbers such as SBR, SSBR, ESBR, PBD/BR, NR and/or synthetic polyisoprene. You can In another example, the composition may contain less than 5 phr, preferably less than 3 phr, of additional diene-based rubber, or be essentially free of such additional diene-based rubber. The terms "compound" and "composition" and "formulation" may be used interchangeably herein unless otherwise indicated.

In a preferred embodiment of the invention, the rubber composition may also contain one or more additional oils, especially (additional) process oils. Processing oil may be included in the rubber composition as a drawing oil typically used to draw elastomers. Processing oil may also be included in the rubber composition by direct addition during rubber compounding. The processing oil used may include both extension oil present in the elastomer and processing oil added during compounding. Suitable process oils include various oils known in the art such as aromatic, paraffinic, naphthenic, vegetable oils, and low PCA oils such as MES, TDAE, SRAE and heavy naphthenic oils. It's okay. Suitable low PCA oils may include those having a polycyclic aromatic (PCA) content of less than 3% by weight as measured by the IP346 method. The IP346 method procedure is described in Standard Methods and British Standard 2000 Parts for the Analysis and Testing of Petroleum and Related Products, 2003, 62nd Edition, 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). Representative examples of (non-aminated and non-epoxidized) vegetable oils that can be used include soybean oil, sunflower oil, canola (rapeseed) oil, corn oil, coconut oil, cottonseed oil, olive oil, palm oil, peanut oil, safflower oil, and the like. mentioned.

In a preferred embodiment of the invention, the rubber composition contains silica. Commonly employed siliceous pigments that can be used in the rubber composition include, for example, conventional pyrogenic and precipitated siliceous pigments (silica). In one embodiment, precipitated silica is used. Conventional siliceous pigments may be precipitated silicas, for example obtained by acidification of soluble silicates such as sodium silicate. Such conventional silicas are characterized, for example, by having a BET surface area measured using nitrogen gas. In one embodiment, the BET surface area may be in the range of 40-600 square meters per gram. In another embodiment, the BET surface area may be in the range of 50-300 square meters per gram. BET surface area is determined herein according to ASTM D5604-96 or an equivalent method. Conventional silicas have dibutyl phthalate (DBP) absorption values in the range of 100 cm ³ /100 g to 400 cm ³ /100 g, alternatively 150 cm ³ /100 g to 300 cm ³ /100 g, which can be suitably determined according to ASTM D 2414 or an equivalent method. It can also be characterized by having Various commercially available silicas can be used, for example silicas sold by PPG Industries under the designations 210, 315G, EZ160G under Hi-Sil™; (trademarks) silica available from Solvay under the designation Premium 200 MP; and silica available from Evonik AG under the designation VN2 and Ultrasil® 6000GR, 9100GR, for example.

In a preferred embodiment of the invention, the rubber composition is for example between 130 m ² /g and 210 m ² /g, optionally between 130 m ² /g and 150 m ² /g and/or 190 m ² /g and 210 m ² /g and even between 195 m ² /g and 205 m ² /g of CTAB adsorption surface area. The CTAB (cetyltrimethylammonium bromide) method (ASTM D6845) for determination of silica surface area is known to those skilled in the art.

Preferred embodiments of the present invention employ surface-modified precipitated silicas that have been treated with at least one silane or silazane prior to addition to the rubber composition. Suitable surface modifiers include, but are not limited to, alkylsilanes, alkoxysilanes, organoalkoxysilylpolysulfides, organomercaptoalkoxysilanes, and hexamethyldisilazane.

The optional silica dispersing aid can be present in an amount ranging from 0.1% to 25% by weight based on the weight of silica, with 0.5% to 20% being preferred; 1% to 15% by weight based on weight are also suitable.

Various pretreated precipitated silicas are described in US Pat. No. 4,704,414, US Pat. No. 6,123,762 and US Pat. No. 6,573,324.

Examples of pretreated silicas suitable for use in the practice of the invention (i.e., silane pretreated silicas suitable for use in the practice of the invention) include Silicas Ciptane® 255 LD and Ciptane® LP (PPG Industries); also organosilane bis(triethoxysilylpropyl) polysulfide (Si69) and Ultrasil® VN3 silica; Coupsil® 8113 and Coupsil® 6508 from Degussa, Agilon® 400 silica from PPG Industries, Agilon® 454 silica from PPG Industries, and Agilon® 458 silica from PPG Industries is included. Representative examples of preferred pre-silanized precipitated silicas include Agilon® 400, Agilon® 454 and Agilon® 458 from PPG Industries.

Representative silica couplers (silica coupling agents) that have sites on pre-silanized precipitated silica and that react with hydroxyl groups on the precipitated silica and another site that interacts with the elastomer include, for example, (A) average bis(3-trialkoxysilylalkyl)polysulfides containing 2 to 4, alternatively 2 to 2.6 or 3.2 to 3.8 sulfur atoms in their connecting bridges, or (B) alkoxyorganomercaptosilanes, or (C) a combination thereof. A typical example of such bis(3-trialkoxysilylalkyl)polysulfide is bis(3-triethoxysilylpropyl)polysulfide. As indicated, in the case of pre-silanized precipitated silica, the silica coupler can desirably be an alkoxyorganomercaptosilane. For precipitated silicas that are not pre-silanized, the silica coupler can be or include bis(3-triethoxysilylpropyl) polysulfide.

In a preferred embodiment of the invention, the rubber composition excludes the addition of silica couplers to the rubber composition (ie excludes silica couplers).

As noted above, in preferred embodiments the rubber composition may include a combination of silica couplers added to the rubber composition. In particular, bis(3-triethoxysilylpropyl)polysulfides containing an average of 2 to 4 connecting sulfur atoms in their polysulfide bridges are added to the rubber composition with additional precipitated silica (not pre-silanized precipitated silica). silica), the ratio of pre-silanized precipitated silica to said precipitated silica is desirably at least 8/1, alternatively at least 10/1.

In a preferred embodiment of the invention, the rubber composition may contain carbon black. Representative examples of such carbon blacks include 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, N991 grades. These carbon blacks have iodine absorptions ranging from 9 g/kg to 145 g/kg and DBP numbers ranging from 34 cm ³ /100 g to 150 cm ³ /100 g. Iodine absorption can be suitably determined according to ASTM D1510 or an equivalent standard. Commonly employed carbon black can be used as a conventional filler in amounts ranging from 10 phr to 150 phr. However, in a preferred embodiment, the composition comprises up to 10 phr carbon black, preferably up to 5 phr carbon black, as preferred embodiments are directed to high silica compounds and improved properties thereof.

In preferred embodiments of the present invention, particulate fillers including ultra high molecular weight polyethylene (UHMWPE), other fillers including crosslinked particulate polymer gels, including those disclosed in US Pat. May be used in objects. those disclosed in U.S. Pat. No. 6,207,757, U.S. Pat. No. 6,133,364, U.S. Pat. No. 6,372,857, U.S. Pat. 5,672,639, including but not limited to plasticized starch composite fillers. Syndiotactic polybutadiene can also be used. Such other fillers may be used in amounts ranging from 1 phr to 30 phr.

In one embodiment, the rubber composition may contain a sulfur-containing organosilicon compound or silane. Examples of suitable sulfur-containing organosilicon compounds are of the formula:
Z-Alk- _Sn -Alk-ZI
where Z is selected from the following group.

wherein R ¹ is an alkyl group having 1 to 4 carbon atoms, cyclohexyl or phenyl, and R ² is alkoxy having 1 to 8 carbon atoms or cycloalkoxy having 5 to 8 carbon atoms; , Alk is a divalent hydrocarbon having 1-18 carbon atoms, and n is an integer from 2-8.

In one embodiment, the sulfur-containing organosilicon compound is 3,3'-bis(trimethoxy or triethoxysilylpropyl) polysulfide. In one embodiment, the sulfur-containing organosilicon compound is 3,3'-bis(triethoxysilylpropyl)disulfide and/or 3,3'-bis(triethoxysilylpropyl)tetrasulfide. Thus, with respect to formula I, Z can be

wherein R ² is alkoxy of 2 to 4 carbon atoms, alternatively 2 carbon atoms, and Alk is a divalent hydrocarbon having 2 to 4 carbon atoms, alternatively 3 carbon atoms; , n is an integer from 2 to 5, or 2 or 4. In another embodiment, suitable sulfur-containing organosilicon compounds include those compounds disclosed in US Pat. No. 6,608,125. In one embodiment, the sulfur-containing organosilicon compound includes 3-(octanoylthio)-1-propyltriethoxysilane, CH ₃ (CH ₂ ) ₆ C(=O), commercially available as NXT from Momentive Performance Materials. -S-CH ₂ CH ₂ Si(OCH ₂ CH ₃ ) ₃ . In another embodiment, suitable sulfur-containing organosilicon compounds include those disclosed in US 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 level of other additives used. Generally, the amount of compound may range from 0.5 phr to 20 phr. In one embodiment, the amount will range from 1 phr to 10 phr.

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

The rubber composition is prepared by methods commonly known in the rubber compounding art, such as various sulfur vulcanizable constituent rubbers and curing aids such as sulfur donors, activators and retarders, and oil. A variety of commonly used additives such as resins, including tackifying resins and plasticizers, processing additives such as fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants, antiozonants and peptizing agents. The ability to mix and blend is readily understood by those skilled in the art. As known to those skilled in the art, depending on the intended use of the sulfur vulcanizable and sulfur vulcanized material (rubber), the above additives are selected and generally used in conventional amounts. used. 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. Sulfur vulcanizing agents may be used, for example, in amounts ranging from 0.5 phr to 8 phr, alternatively in amounts ranging from 1.5 phr to 6 phr. If a tackifier resin is used, typical amounts of tackifier resin include, for example, 0.5 phr to 10 phr, usually 1 phr to 5 phr. If processing aids are used, typical amounts of processing aids are included, eg, 1 phr to 50 phr (which may include oils, among others). Where antioxidants are used, typical amounts of antioxidants may be included, eg, 1 phr to 5 phr. Representative antioxidants may be, for example, diphenyl-p-phenylenediamine and others, such as those disclosed in the Vanderbilt Rubber Handbook (1978), pages 344-346. If an antiozonant is used, it may contain typical amounts of antiozonant, eg, 1 phr to 5 phr. When a fatty acid, which may include stearic acid, is used, typical amounts of fatty acid, which may include stearic acid, may be included, for example 0.5 phr to 3 phr. If waxes are used, typical amounts of waxes are used at levels within the range of 1 phr to 5 phr. Microstalin wax is often used. If a peptizing agent is used, typical amounts of peptizing agent are usually in the range of 0.1 phr to 1 phr. A typical peptizing agent can be, for example, pentachlorothiophenol and/or dibenzamide diphenyl disulfide.

Accelerators are preferably, but not necessarily, used to control the time and/or temperature required for vulcanization and to improve the properties of the vulcanizate. In one embodiment, a single accelerator system may be used, ie, primary accelerator. Primary accelerators may be used in total amounts ranging from 0.5 phr to 4 phr, alternatively 0.8 phr to 1.5 phr. In another embodiment, a combination of primary and secondary accelerators is used with a lower amount of secondary accelerator, such as from 0.05 phr to 3 phr, to activate the vulcanizate and improve properties. may Combinations of these accelerators are expected to have a synergistic effect on the final properties and are somewhat superior to either accelerator used alone. In addition, delayed action accelerators may be used which are not affected by normal processing temperatures and provide satisfactory cures at normal vulcanization temperatures. Vulcanization retarders can also be used. Suitable classes of accelerators that may be used in the present 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 secondary accelerator is used, the secondary accelerator can be, for example, a guanidine, dithiocarbamate or thiuram compound. Suitable guanidines include diphenylguanidine and the like. Suitable thiurams include tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabenzylthiuram disulfide and the like.

Mixing of the rubber composition can be accomplished by methods known to those skilled in the rubber mixing art. For example, the ingredients may typically be mixed in at least two stages, namely at least one non-productive stage followed by a productive mix stage. A final curative containing a sulfur vulcanizing agent is typically used as a "productive" mix stage in which mixing is typically performed at a temperature lower than the mix temperature of the preceding non-productive mix stage, i.e., the ultimate temperature. , may be mixed in what is conventionally called the final stage. In embodiments, the rubber composition may be subjected to a thermomechanical mixing process. The thermomechanical mixing step generally involves mechanical operation in a mixer or extruder for a suitable period of time to produce a rubber temperature between, for example, 140°C and 190°C. Appropriate times for thermo-mechanical processing will vary as a function of operating conditions and the amount and nature of the constituents. For example, thermo-mechanical processing may be between 1 minute and 20 minutes.

In a preferred embodiment of the invention there is provided a rubber article comprising the rubber composition according to the invention selected from tires, power transmission belts, hoses, tracks, air sleeves and conveyor belts.

In a preferred embodiment of the present invention, rubber products made of the rubber composition according to the present invention are treads, shear bands, rubber spokes, undertreads, sidewalls, apex, flippers, chippers, chafers, carcasses, belts, overlays, etc. The selected tire comprises one or more rubber components, one or more of which comprises the rubber composition. In a preferred embodiment, the tire has a tread made from a rubber composition. In a preferred embodiment the tire has a tread with one or more tread cap layers and the rubber composition according to the invention is in one or more of the two radially outermost tread cap layers, preferably In the radially outermost tread cap layer.

In another embodiment, the rubber composition is in a tread cap layer radially inward of the radially outermost tread cap layer. The rubber composition according to the invention is then optionally absent from the radially outermost tread cap layer. In such embodiments, the radially outermost tread cap layer does not contain the rubber composition according to the present invention. In contrast, the rubber composition of the tread cap layer radially below the radially outermost tread cap layer has a rubber composition according to the present invention (or one or more of its embodiments). Such an arrangement or configuration helps maintain grip height, particularly wet grip, at a similar height as the first tread cap layer wears and the radial rib or block height of the tread decreases. can help. And the loss of tread height can be at least partially compensated for by the improved grip of the rubber composition according to the invention.

Vulcanization of the pneumatic tire of the present invention can be carried out at conventional temperatures, for example in the range of 100°C to 200°C. In one embodiment, vulcanization is carried out at a temperature in the range of 110°C to 180°C. For the vulcanization process, any ordinary vulcanization process such as heating with a press or a mold, or heating with superheated steam or hot air may be used. However, the tires of the present invention are generally preferably vulcanized at temperatures in the range of 132°C to 166°C, more typically in the range of 143°C to 154°C. Such tires can be constructed, shaped, molded and cured by a variety of known methods and will be readily apparent to those skilled in such art.

The structure, operation and advantages of the present invention will become more apparent upon consideration of the following description taken in conjunction with the accompanying drawings.
1 is a schematic cross-sectional view of a tire made of a rubber member having a rubber composition according to an embodiment of the present invention; FIG.

FIG. 1 is a schematic cross-sectional view of a tire 1 according to one embodiment of the invention. The tire 1 includes a tread 10, an inner liner 13, a belt consisting of four belt plies 11, a carcass ply 9, two sidewalls 2, two bead regions 3, a bead filler apex 5, a bead 4, and the like. A plurality of tire components are provided. The tire 1 of this example is suitable, for example, for mounting on the rim of a vehicle such as a truck or a passenger car. As shown in FIG. 1, belt ply 11 may be covered by overlay ply 12 and/or may include one or more breaker plies. The carcass ply 9 includes a pair of axially opposed end portions 6 each associated with a respective one of the beads 4 . Each axial end portion 6 of the carcass ply 9 may be folded around the respective bead 4 to a position that secures each axial end portion 6 . The turned-up portion 6 of the carcass ply 9 may engage the axially outer surfaces of two flippers 8 and the axially inner surfaces of two chippers 7, which are also tire components. As shown in FIG. 1 , the exemplary tread 10 may have circumferential grooves 20 , each groove 20 essentially defining a U-shaped opening in the tread 10 . A major portion of tread 10 may be formed of one or more tread compounds. Further, grooves 20, particularly the bottom and/or sidewalls of grooves 20, may be reinforced with a rubber compound having a higher hardness and/or stiffness than the rest of the tread compound. Such reinforcement may be referred to herein as groove reinforcement.

Although the embodiment of FIG. 1 suggests multiple tire components including, for example, apex 5, chipper 7, flipper 8 and overlay 12, such components and further components are essential to the present invention. not. Also, the turn-up end of the carcass ply 9 is not essential to the invention, or passes through the opposite side of the bead area 3 and is the axially inner end of the bead 4 instead of the axially outer side of the bead 4. good too. Also, the tire may for example have a different number of grooves 20, for example four grooves or less.

In embodiments, the tire 1 or other tire tread 10 comprises a rubber composition according to the inventive examples, as specified in Table 1 below. A rubber composition according to a preferred embodiment of the present invention is used for a tread or tread layer in contact with a road.

Sprintan® SLR 3402 from Trinseo with a Tg of ^1-62 ° C. and a thiol-alkoxysilane functionality
² HPR 355H from JSR Corporation with a Tg of about -27°C and an aminosilane functional group
³ natural rubber
⁴ Dercolyte® A115 from DRT with a Tg of about 70°C
⁵ ExxonMobil Oppera® 383 with a Tg of about 54°C
⁶ BET specific surface area 15 m ² /g, d50 0.4 µm, d90 0.8 µm,
Al(OH) ₃ with a d10 of 0.3 μm and a material density of 2.4 g/ ^cm3
Zeosil® from Solvay with a BET surface area of ⁷ 215 m ² /g
Premium 200MP
^8- bistriethoxysilylpropyl disulfide
^9- bis-triethoxysilylpropyl tetrasulfide
¹⁰ Based on dihydroquinoline and phenylenediamine.
¹¹ 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane, Vulcuren® from LANXESS containing about 10% oil and carbon black
¹² TBBS and DPG type

Table 2 shows the tire characteristics obtained based on the comparative examples and the invention examples shown in Table 1 above. As is clear from the following results, in the examples of the present invention, by changing the type of resin, wet grip and tread wear are surprisingly greatly improved. Wet grip is also flat, indicating an improved overall balance of these properties.

^a Laboratory test, based on dynamic mechanical analysis (DMA) of tangential delta shear response at 30° C., normalized to comparative example (unit: %).
^b Laboratory test by measuring the transmitted friction force with a linear friction tester, the result normalized by the comparative example (unit: %).
^c Test results (unit: %) normalized to the comparative examples based on the amount of wear measured according to ASTM D5963.

Claims (10)

70 phr to 100 phr of at least one styrene butadiene rubber;
0 phr to 30 phr of at least one further diene-based rubber;
40 phr to 200 phr of at least one filler;
A rubber composition comprising at least 5 phr of aluminum hydroxide and at least one hydrocarbon resin selected from one or more of DCPD resins, CPD resins and C5 resins. 2. The rubber composition of claim 1, wherein said rubber composition comprises from 5 phr to 80 phr of aluminum hydroxide and/or said rubber composition comprises from 15 phr to 80 phr of said hydrocarbon resin. 2. The rubber composition according to claim 1, wherein said hydrocarbon resin is a hydrogenated hydrocarbon resin and/or said hydrocarbon resin is an aromatic modified product. 2. The rubber composition of claim 1, wherein said at least one styrene-butadiene rubber is a solution-polymerized styrene-butadiene rubber and said at least one diene-based rubber is synthetic polyisoprene, natural rubber, or both. The at least one styrene-butadiene rubber is (i) a first styrene-butadiene rubber having a glass transition temperature within the range of -51°C to -86°C, and (ii) within the range of -10°C to -45°C. and optionally at least one of said first and second styrene-butadiene rubbers is functionalized for coupling with silica. Item 5. The rubber composition according to item 4. 2. A rubber composition according to claim 1, wherein said filler comprises predominantly silica and/or said filler comprises less than 10 phr of carbon black and at least 40 phr of silica. 2. The rubber composition of claim 1, comprising one or both of (i) from 0 phr to less than 5 phr of an additional resin; and (ii) from 0 phr to less than 5 phr of an oil, apart from said hydrocarbon resin. one of the first and second styrene-butadiene rubbers is functionalized with at least one thiol group; and another one of the first and second styrene-butadiene rubbers is functionalized with at least one aminosilane or aminosiloxane group. 2. The rubber composition of claim 1, wherein the rubber composition is A tire comprising the rubber composition according to any one of claims 1 to 8. 10. The tire of claim 9, having a tread with an axially outermost tread cap layer, the axially outermost tread cap layer comprising said rubber composition.

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