Rubber composition and rubber product

Abstract

To provide an advanced rubber composition having improved reinforcement properties.SOLUTION: A rubber composition comprises: 100 phr of one or more diene-based elastomers; 30 phr to 200 phr of a filler; and a benzoxazine based on reaction of (i) a diphenol comprising two phenol groups and a bridge covalently connecting the two phenol groups, (ii) an aldehyde derivative, and (iii) an amine, where the bridge is connected to at least one of the phenol groups at a meta position of the at least one phenol group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a rubber composition or unvulcanized rubber composition for rubber products such as tires or tire components. [Background technology]

[0002] The use of reinforcing resins has helped further improve tire performance over the past few decades. In particular, reactive resin systems based on methylene donors and methylene acceptors, also known as novolac resins, have been used to enhance the properties of different rubber compositions by reacting in situ during rubber compounding. However, the use of such resins requires the handling of methylene donors, also known as formaldehyde donors, and resorcinol during the rubber compounding process, which may be undesirable from an environmental, health, and / or safety standpoint. Furthermore, there is a demand for further improvements in reinforcing properties, especially with limited weight and hysteresis. Therefore, there remains considerable room for improvement in the field of reinforcing resins used in rubber compositions, particularly tires. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] U.S. Patent No. 5,698,643 [Patent Document 2] U.S. Patent No. 5,451,646 [Patent Document 3] U.S. Patent No. 4,704,414 [Patent Document 4] U.S. Patent No. 6,123,762 [Patent Document 5] U.S. Patent No. 6,573,324 [Patent Document 6] U.S. Patent No. 6,242,534 [Patent Document 7] U.S. Patent No. 6,207,757 [Patent Document 8] U.S. Patent No. 6,133,364 [Patent Document 9] U.S. Patent No. 6,372,857 [Patent Document 10] U.S. Patent No. 5,395,891 [Patent Document 11] U.S. Patent No. 6,127,488 [Patent Document 12] U.S. Patent No. 5,672,639 [Patent Document 13] U.S. Patent No. 6,608,125 [Patent Document 14] U.S. Patent Application Publication No. 2003 / 0130535 [Non-patent literature]

[0004] [Non-Patent Document 1] Journal of the American Chemical Society, Vol. 60, p. 304 (1930) [Non-patent document 2] The Vanderbilt Rubber Handbook (1978), pp. 344-346 Summary of the Invention [Problem to be solved by the invention]

[0005] One object of the present invention can be to provide an advanced rubber composition with improved reinforcing properties. Another object of the present invention may be to provide a rubber composition having good stiffness, optionally with limited hysteresis.

[0006] Another object of the present invention can be to provide a rubber composition that allows for a reduction in the amount of methylene donor handled during the manufacture of the rubber composition. Another object of the present invention may be to provide a cost-effective alternative to existing reactive resin systems.

[0007] The scope of protection of the present invention is defined by independent claim 1. Further preferred embodiments are detailed in the dependent claims, as well as in the aspects and embodiments provided herein below in the summary and description. [Means for solving the problem]

[0008] Thus, in a first aspect, the present invention is directed to a rubber composition comprising 100 phr of one or more, preferably diene-based, elastomers, 30 to 200 phr of filler, and a benzoxazine based on (or which is the reaction product of) i) a diphenol containing two phenolic groups and a bridge covalently linking or interconnecting the two phenolic groups, ii) an aldehyde derivative, and iii) an amine, wherein the bridge links at least one phenolic group at the (each) meta position of the at least one phenolic group. The inventors have found that the use of such benzoxazines provides excellent reinforcing properties. Furthermore, such benzoxazines can be prepared in advance and then added to the rubber composition, thereby eliminating the need to handle reactive resin reactants during rubber composition preparation. Furthermore, it has been found that providing a diphenol-based benzoxazine bridged at at least one meta position of one of the phenolic groups provides improved reinforcing properties over other configurations, as the para and ortho positions are unblocked and available for crosslinking in the rubber network.

[0009] In another embodiment, the amine is a primary amine (ie, a molecule having an amino group). In another embodiment, the aldehyde derivatives include formaldehyde, paraformaldehyde, polyoxymethylene, and alkoxysilanes of the formula RCHO, where R is a substituted or unsubstituted aliphatic C-C alkylene ... 20In particular, the reaction can occur in the presence of formaldehyde. Although formaldehyde is involved in the reaction to form the benzoxazine, such reaction does not occur during the preparation of the rubber composition, and preformed benzoxazines can be added to the rubber composition.

[0010] In yet another embodiment, the amine or primary amine is selected from the group of aromatic amines, aliphatic amines, cycloaliphatic amines, and heterocyclic amines. In yet another embodiment, the amine or primary amine is selected from the group of ethanolamine, allylamine, methylamine, ethylamine, propylamine, butylamine, isopropylamine, hexylamine, cyclohexylamine, 2-aminofluorene, aminophenylacetylene, propargyl ether aniline, 4-aminobenzonitrile, furfurylamine, aniline.

[0011] In yet another embodiment, and in the case of aliphatic amines, the aliphatic amine comprises a carbon chain of less than 18 carbon atoms, in particular, longer chains have been found to impair crosslinking in the rubber network.

[0012] In yet another embodiment, the bridge comprises one of an aromatic group, an aliphatic group, an alicyclic group, a heterocyclic group, a hexafluoropropane group, a monosulfide, an oxygen group, a sulfone group, and a disulfide. In particular, disulfide groups or bridges are of great interest in sulfur vulcanizable, or in other words, sulfur crosslinkable, rubbers because they add another valuable aspect to the crosslinking.

[0013] In one embodiment, the diphenol is selected from 3,4'-dihydroxydiphenyl disulfide and 3,3'-dihydroxydiphenyl disulfide. These diphenols have been found to provide good reinforcing properties at limited cost.

[0014] In yet another embodiment, the benzoxazine has the following structure:

[0015] [ka]

[0016] wherein R1 and R2 are selected from aromatic, aliphatic, alicyclic, and heterocyclic groups, and R3 is an aromatic, aliphatic, alicyclic, heterocyclic, hexafluoropropane, monosulfide (S), or disulfide (SS). As can be seen from the structural diagram above, when R3 is attached at the meta position, the ortho and para positions are available. This further improves crosslinking in the rubber network.

[0017] In yet another embodiment, R1 and R2 are selected from ethanol, allyl, methyl, ethyl, propyl, isopropyl, hexyl, cyclohexyl, fluorene, phenylacetylene, propargyl ether benzyl, benzonitrile, furfuryl, and benzyl groups.

[0018] In yet another embodiment, R3 is disulfide (SS). In yet another embodiment, the rubber composition is a sulfur vulcanizable rubber composition that includes a sulfur donor.

[0019] In yet another embodiment, the rubber composition is a (sulfur) vulcanized rubber composition. In yet another embodiment, the filler comprises one or more of silica, carbon black, aluminum hydroxide, ultra-high molecular weight polyethylene, and syndiotactic polybutadiene. Preferably, at least 50 phr of the filler comprises carbon black and / or silica.

[0020] In yet another embodiment, the rubber composition is a sulfur vulcanizable (i.e., unvulcanized or uncured) rubber composition containing less than 2 phr, preferably less than 1 phr, and even more preferably less than 0.5 phr of methylene donor and / or less than 5 phr of methylene acceptor (as present in a reactive resin system).

[0021] In yet another embodiment, the rubber composition includes an additional benzoxazine based on the reaction of a phenol with a primary amine. For example, the additional or second benzoxazine can be one or more of monofunctional benzoxazines and main-chain benzoxazines. In particular, such second benzoxazines with at least one functional group (e.g., silane, long alkyl chain, or carboxylic acid) can provide additional functionality and be incorporated into the benzoxazine network after the curing step. They can further improve processability, reinforcement, and / or hysteresis, and / or improve filler, rubber interaction, and / or cure package.

[0022] In yet another embodiment, the rubber composition comprises 5 phr to 40 phr, or 5 phr to 9 phr, or 10 phr to 20 phr, or 20 phr to 40 phr, or 10 phr to 40 phr of benzoxazine.

[0023] In embodiments, the rubber composition may contain at least one and / or an additional diene-based rubber. Representative synthetic polymers may be butadiene and its homologs and derivatives, such as the homopolymerization products of methylbutadiene, dimethylbutadiene, and pentadiene, as well as copolymers with other unsaturated monomers, such as those formed from butadiene or its homologs or derivatives. Among the latter may be acetylene, such as vinyl acetylene; olefins, such as isobutylene, 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 compound polymerizes with butadiene to form SBR), as well as 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 neoprene (polychloroprene), polybutadiene (including cis-1,4-polybutadiene), polyisoprene (including cis-1,4-polyisoprene), butyl rubber, halobutyl rubbers such as chlorobutyl 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)), particularly ethylene / propylene / dicyclopentadiene terpolymers. Additional examples of rubbers that may be used include alkoxysilyl-terminated solution-polymerized polymers (SBR, PBR, IBR, and SIBR), and silicon- or tin-coupled star-branched polymers. Preferred rubbers or elastomers may generally be natural rubber, synthetic polyisoprene, polybutadiene, and SBR, including SSBR.

[0024] In another embodiment, the composition may comprise at least two diene-based rubbers, such as combinations of two or more rubbers, such as cis-1,4-isoprene rubber (which may be natural or synthetic, but is preferably natural), 3,4-isoprene rubber, styrene / isoprene / butadiene rubber, emulsion and solution polymerization-derived styrene / butadiene rubber, cis-1,4-polybutadiene rubber, and emulsion polymerization-prepared butadiene / acrylonitrile copolymers.

[0025] In another embodiment, emulsion polymerization-derived styrene / butadiene (ESBR) having a styrene content of 20 to 28 percent bound styrene may be used, or for some applications, ESBR having a moderate to relatively high bound styrene content, i.e., 30 to 45 percent bound styrene. In many cases, the ESBR has a bound styrene content in the range of 26 to 31 percent. By emulsion polymerization-prepared ESBR, it is meant that styrene and 1,3-butadiene are copolymerized as an aqueous emulsion, as is well known to those skilled in the art. The bound styrene content can vary, for example, from 5 to 50 percent. In one embodiment, the ESBR may also contain acrylonitrile to form a terpolymer rubber as an ESBAR, for example, in an amount of 2 to 30 weight percent bound acrylonitrile in the terpolymer. Emulsion polymerization-prepared styrene / butadiene / acrylonitrile copolymer rubber containing 2 to 40 weight percent bound acrylonitrile in the copolymer may also be contemplated as a diene-based rubber.

[0026] In another embodiment, solution-polymerized SBR (SSBR) may be used. Such SSBRs have bound styrene contents of, for example, 5 to 50 percent, preferably 9 to 36 percent, and most preferably 26 to 31 percent. SSBRs can be conveniently prepared, for example, by anionic polymerization in an inert organic solvent. Specifically, SSBRs 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, solution styrene-butadiene rubber is a tin-coupled polymer. In yet another embodiment, SSBRs are functionalized to improve compatibility with silica. Additionally or alternatively, SSBRs are thio-functionalized, which helps improve the stiffness and / or hysteresis behavior of the compound. Thus, for example, SSBRs can be thio-functionalized, tin-coupled solution-polymerized copolymers of butadiene and styrene.

[0027] In one embodiment, synthetic or natural polyisoprene rubber can be used. Synthetic cis-1,4-polyisoprene and natural rubber are well known as such to those skilled in the rubber art. In particular, the cis-1,4-microstructure content may be at least 90%, typically at least 95%, or even higher.

[0028] In one embodiment, cis-1,4-polybutadiene rubber (BR or PBD) is 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 at least 90 percent cis-1,4-microstructure content ("high cis" content) and a glass transition temperature (Tg) in the range of -95 to -110°C. Suitable polybutadiene rubbers, such as Budene® 1207, Budene® 1208, Budene® 1223, or Budene® 1280, are commercially available from The Goodyear Tire & Rubber Company. These high cis-1,4-polybutadiene rubbers can be synthesized using a nickel catalyst system containing a mixture of (1) an organonickel compound, (2) an organoaluminum compound, and (3) a fluorine-containing compound, as described, for example, in U.S. Pat. Nos. 5,698,643 and 5,451,646, which are incorporated herein by reference.

[0029] The glass transition temperature (Tg) of an elastomer or elastomeric composition referred to herein refers to the glass transition temperature of the respective elastomer or elastomeric composition in its uncured state, or possibly in the case of elastomeric compositions, in the cured state. Tg may be suitably determined by differential scanning calorimetry (DSC) according to ASTM D3418 as the peak midpoint at a temperature ramp rate of 10°C per minute.

[0030] The term "phr," as used herein, refers, in accordance with conventional practice, to "parts by weight of each material per 100 parts by weight of rubber or elastomer." Generally, using this convention, a rubber composition is composed of 100 parts by weight of rubber / elastomer. A claimed composition may contain rubbers / elastomers other than those explicitly recited in the claim, so long as the phr values ​​of the claimed rubbers / elastomers are consistent with the claimed phr ranges and the amounts of all rubbers / elastomers in the composition total 100 parts rubber. By way of example, the composition may further include 1 to 10 phr, and in some cases 1 to 5 phr, of one or more additional diene-based rubbers, such as SBR, SSBR, ESBR, PBD / BR, NR, and / or synthetic polyisoprene. In another example, the composition may include less than 5 phr, preferably less than 3 phr, of additional diene-based rubber, or may be essentially free of such additional diene-based rubbers. The terms "compound" and "composition" and "formulation" may be used interchangeably herein unless otherwise indicated.

[0031] In an embodiment, the rubber composition may also contain an oil, particularly a process oil. The process oil may be included in the rubber composition as an extender oil, typically used to extend elastomers. The process oil may also be included in the rubber composition by direct addition of the oil during rubber compounding. The process oil used may be included in both the extender oil present in the elastomer and the process oil added during compounding. Suitable process oils include various oils known in the art, including low PCA oils such as aromatic, paraffinic, naphthenic, vegetable, MES, TDAE, SRAE, and heavy naphthenic oils. Suitable low PCA oils may include those having a polycyclic aromatic content of less than 3 weight percent as determined by the IP346 method. The IP346 method procedure 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 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, and safflower oil. Soybean oil and corn oil are typically preferred vegetable oils. If used, the rubber composition may also contain up to 70 phr of processing oil, preferably between 5 and 25 phr, or alternatively less than 10 phr, preferably less than 5 phr.

[0032] In embodiments, the rubber composition may contain silica. Commonly used siliceous pigments that may be used in rubber compounds include, for example, conventional calcined and precipitated siliceous pigments (silica). In one embodiment, precipitated silica is used. The conventional siliceous pigment may be, for example, a precipitated silica, such as that obtained by acidifying a soluble silicate, e.g., sodium silicate. Such conventional silica may be characterized by having a BET surface area, measured, for example, using nitrogen gas. In one embodiment, the BET surface area may be in the range of 40 to 600 square meters per gram. In another embodiment, the BET surface area may be in the range of 50 to 300 square meters per gram. BET surface area may be suitably determined by ASTM D6556 or equivalent, as described in Journal of the American Chemical Society, Vol. 60, p. 304 (1930). Conventional silicas also have a surface area of ​​100 cm. 3 / 100g~400cm 3 / 100g, alternatively 150cm 3 / 100g~300cm 3 The silica may be characterized as having a dibutyl phthalate (DBP) absorption value in the range of 0.01 to 0.05 microns / 100 g, suitably determined according to ASTM D 2414 or equivalent. Conventional silicas can be expected to have an average ultimate particle size in the range of 0.01 to 0.05 microns, as determined, for example, by electron microscopy, although silica particles may be smaller or possibly larger in size. Silica usage ranges may be, for example, between 5 and 120 phr, preferably between 20 and 70 phr or 80 to 120 phr. Various commercially available silicas may be used herein, including, by way of example only and without limitation, silicas available from PPG Industries under the Hi-Sil trademark, such as those with the designations 210, 315G, EZ160G, etc.; silicas available from Solvay, such as those with the designations Z1165MP and Premium200MP, and silicas available from Evonik AG, such as those with the designations VN2, Ultrasil 6000GR, 9100GR, etc.

[0033] In yet another embodiment, the rubber composition may be, for example, 130 ml 2 / g to 210m 2 / g, sometimes 130m 2 / g to 150m 2 / g and / or 190m 2 / g to 210m 2 / g or a further 195m 2 / g to 205m 2 / g。 The CTAB (cetyltrimethylammonium bromide) method (ASTM D6845) for measuring silica surface area is known to those skilled in the art.

[0034] In another embodiment, the pre-silanized (or pre-hydrophobized) precipitated silica used is hydrophobized by treatment with at least one silane prior to addition to the rubber composition. Suitable silanes include, but are not limited to, alkylsilanes, alkoxysilanes, organoalkoxysilyl polysulfides, and organomercaptoalkoxysilanes.

[0035] The optional silica dispersing aid, if used, may be present in an amount ranging from about 0.1% to about 25% by weight based on the weight of silica, with about 0.5% to about 20% being suitable, and about 1% to about 15% by weight based on the weight of silica being also suitable. Various pretreated precipitated silicas are described in U.S. Patent Nos. 4,704,414, 6,123,762, and 6,573,324, the teachings of which are incorporated herein by reference.

[0036] Some non-limiting examples of pretreated silicas (i.e., silicas pre-surface treated with silanes) suitable for use in the practice of the present invention include, but are not limited to, Ciptane® 255 LD and Ciptane® LP (PPG Industries) silicas pretreated with mercaptosilanes, and Coupsil® 8113 (Degussa), which is the product of the reaction between organosilane bis(triethoxysilylpropyl) polysulfide (Si69) and Ultrasil® VN3 silica, and Coupsil® 6508, 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 silicas include Agilon® 400, Agilon® 454, and Agilon® 458 from PPG Industries.

[0037] Representative silica couplers (silica coupling agents) having a portion of the presilanized precipitated silica and precipitated silica reactive with hydroxyl groups and another portion that interacts with the elastomer may comprise, for example: (A) a bis(3-trialkoxysilylalkyl) polysulfide containing an average of about 2 to about 4, alternatively about 2 to about 2.6, or about 3.2 to about 3.8, sulfur atoms in the bridges it connects; (B) an alkoxyorganomercaptosilane; or (C) a combination thereof. Representative of such bis(3-trialkoxysilylalkyl) polysulfides is bis(3-triethoxysilylpropyl) polysulfide. As indicated, for presilanized precipitated silicas, the silica coupler may desirably be an alkoxyorganomercaptosilane. For non-presilanized precipitated silicas, the silica coupler may desirably be bis(3-triethoxysilylpropyl) polysulfide.

[0038] In one embodiment, the rubber composition excludes the addition of a silica coupler to the rubber composition (thereby excluding a silica coupler). As indicated, in one embodiment, the rubber composition may contain a combination of additional silica coupler added to the rubber composition, particularly bis(3-triethoxysilylpropyl) polysulfide containing an average of about 2 to about 4 connecting sulfur atoms in the polysulfide bridge, along 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 desirably at least 8 / 1, or alternatively at least 10 / 1.

[0039] In embodiments, the rubber composition may include 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 an iodine absorption ranging from 9 to 145 g / kg and a DBP number ranging from 34 to 150 cm3 / 100 g. Iodine absorption values ​​may be suitably determined according to ASTM D1510 or equivalent. Commonly used carbon black may be used as a conventional filler in amounts ranging from 10 to 150 phr. In another embodiment, 20 to 80 phr of carbon black may be used.

[0040] In another embodiment, other fillers that may be used in the rubber composition include, but are not limited to, particulate fillers including ultra-high molecular weight polyethylene (UHMWPE), crosslinked particulate polymer gels, including but not limited to those disclosed in U.S. Patent Nos. 6,242,534; 6,207,757; 6,133,364; 6,372,857; 5,395,891; and 6,127,488, and plasticized starch composite fillers, including but not limited to those disclosed in U.S. Patent No. 5,672,639. Other such fillers may be used in amounts ranging from 1 to 30 phr.

[0041] In one embodiment, the rubber composition may contain conventional sulfur-containing organosilicon compounds or silanes. Examples of suitable sulfur-containing organosilicon compounds include those represented by the formula: Z - Alk - S n -Alk-ZI [Wherein Z is

[0042] [ka]

[0043] (In the formula, R 1 is an alkyl group of 1 to 4 carbon atoms, cyclohexyl, or phenyl; R 2 is an alkoxy of 1 to 8 carbon atoms or a cycloalkoxy of 5 to 8 carbon atoms) wherein Alk is a divalent hydrocarbon of 1 to 18 carbon atoms and n is an integer from 2 to 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, for formula I, Z is:

[0044] [ka]

[0045] [In the formula, R 2 is an alkoxy of 2 to 4 carbon atoms, alternatively 2 carbon atoms; Alk is a divalent hydrocarbon of 2 to 4 carbon atoms, alternatively 3 carbon atoms; and n is an integer of 2 to 5, alternatively 2 or 4. In another embodiment, suitable sulfur-containing organosilicon compounds include those disclosed in U.S. Pat. No. 6,608,125. In one embodiment, the sulfur-containing organosilicon compound includes 3-(octanoylthio)-1-propyltriethoxysilane, CH3(CH2)6C(=O)-S-CH2CH2CH2Si(OCH2CH3)3, commercially available from Momentive Performance Materials as NXT™. 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 a rubber composition may vary depending on the level of other additives used. Generally, the amount of compound ranges from 0.5 to 20 phr. In one embodiment, the amount ranges from 1 to 10 phr.

[0046] In another embodiment, the rubber composition comprises less than 0.1 phr of a cobalt salt or 0 phr of a cobalt salt. Those skilled in the art will readily appreciate that rubber compositions can be compounded by methods commonly known in the rubber compounding art, such as blending various constituent sulfur-vulcanizable rubbers with various commonly used additives, such as sulfur donors, curing aids, e.g., activators and retarders, and processing additives such as oils, resins including tackifiers and plasticizers, fillers, pigments, fatty acids, zinc oxide, waxes, antioxidants, antiozonants, and peptizers. As known to those skilled in the art, the additives listed above are selected and generally used in conventional amounts depending on the intended use of the sulfur-vulcanizable and sulfur-vulcanized materials (rubbers). 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 may be used in an amount ranging from 0.5 phr to 8 phr, alternatively from 1.5 phr to 6 phr. A typical amount of tackifying resin, if used, comprises, for example, 0.5 phr to 10 phr, usually 1 phr to 5 phr. A typical amount of processing aid, if used, comprises, for example, 1 phr to 50 phr. (This may include, inter alia, oils.) A typical amount of antioxidant, if used, comprises, for example, 1 phr to 5 phr. A typical antioxidant may be, for example, diphenyl-p-phenylenediamine or others, such as those disclosed in The Vanderbilt Rubber Handbook (1978), pp. 344-346. A typical amount of antiozonant, if used, may comprise, for example, 1 phr to 5 phr. A typical amount of fatty acid, if used, may include stearic acid and may comprise, for example, 0.5 phr to 3 phr. A typical amount of wax, if used, may comprise, for example, 1 phr to 5 phr. Microcrystalline waxes are often used. A typical amount of peptizer, if used, may comprise, for example, 0.1 phr to 1 phr. Typical peptizers may be, for example, pentachlorothiophenol and dibenzamidodiphenyl disulfide.

[0047] Accelerators can be used to control the time and / or temperature required for vulcanization and to improve the properties of the vulcanizate, but are not required. In one embodiment, a single accelerator system, i.e., a primary accelerator, may be used. The primary accelerator(s) may be used in total amounts ranging from 0.5 phr to 4 phr, alternatively from 0.8 phr to 1.5 phr. In another embodiment, a combination of primary and secondary accelerators may be used, with the secondary accelerator being used in a lower amount, such as from about 0.05 to about 3 phr, to activate and improve the properties of the vulcanizate. These accelerator combinations can be expected to produce a synergistic effect on the final properties, which are somewhat better than those produced by either accelerator used alone. Additionally, delayed-action accelerators may be used that are not affected by normal processing temperatures but produce a satisfactory cure at ordinary vulcanization temperatures. Vulcanization retarders may also be used. Suitable types of accelerators that may be used in the present invention include, for example, amines, disulfides, guanidines, thioureas, thiazoles, thiurams, sulfenamides, dithiocarbamates, and xanthates. In one embodiment, the primary accelerator is a sulfenamide. If a second accelerator is used, the secondary accelerator may be, for example, a guanidine, dithiocarbamate, or thiuram compound. Suitable guanidines include diphenylguanidine, etc. Suitable thiurams include tetramethylthiuram disulfide, tetraethylthiuram disulfide, and tetrabenzylthiuram disulfide.

[0048] The mixing of the rubber composition can be accomplished by methods known to those skilled in the rubber mixing art. For example, the raw materials may typically be mixed in at least two stages: at least one non-productive stage followed by a productive mix stage. The final curative, including the sulfur vulcanizing agent, may typically be mixed in the final stage, conventionally referred to as the "productive" mix stage, where mixing is typically conducted at a temperature or final temperature lower than the mixing temperature(s) of the preceding non-productive mix stage(s). The terms "non-productive" and "productive" mix stages are well known to those skilled in the rubber mixing art. In embodiments, the rubber composition may be subjected to a thermodynamic mixing step. The thermodynamic mixing step generally involves mechanical operation in a mixer or extruder for a period of time suitable to produce a rubber temperature, for example, between 140°C and 190°C. The suitable duration of the thermodynamic operation varies as a function of the operating conditions and the amount and nature of the components. For example, the thermodynamic operation may be from 1 to 20 minutes.

[0049] Vulcanization of the pneumatic tires 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. Any of the usual vulcanization methods may be used, such as heating in a press or mold, heating with superheated steam or hot air, etc. Such tires can be built, shaped, molded, and cured by a variety of methods known and readily apparent to those skilled in the art.

[0050] In a second aspect, the present invention provides a composition comprising 100 phr of one or more elastomers, preferably diene-based, 30 phr to 200 phr of a filler, and a composition having the following structure:

[0051] [ka]

[0052] wherein R1 and R2 are selected from aromatic, aliphatic, alicyclic, and heterocyclic groups, and R3 is an aromatic, aliphatic, alicyclic, heterocyclic, hexafluoropropane, monosulfide, or disulfide. and a benzoxazine having at least one of the following:

[0053] The second aspect and also other aspects mentioned herein may be combined with embodiments mentioned in the context of other aspects, in particular with the first aspect of the invention. In a third aspect of the present invention, there is provided a rubber article comprising a rubber composition according to the first aspect above, or according to one or more of its embodiments.

[0054] In one embodiment, the rubber product is selected from tires, power transmission belts, hoses, trucks, air sleeves, and conveyor belts. The tires may be, for example, pneumatic or non-pneumatic tires.

[0055] In a further embodiment, the rubber product is a tire comprising one or more rubber components selected from a tread, a rubber shear band, a rubber spoke, an undertread, a sidewall, an apex, a flipper, a chipper, a chafer, a carcass, a belt, an overlay, one or more of the rubber components comprising a rubber composition.

[0056] In another embodiment, the rubber article is a tire comprising an apex or tread groove reinforcement comprising the rubber composition. In particular, the apex or tread groove reinforcement composition can benefit from the reinforcing properties of the rubber composition disclosed herein.

[0057] Tires according to embodiments of the present invention may be, for example, pneumatic or non-pneumatic tires, race tires, passenger tires, aircraft tires, agricultural tires, earthmoving tires, off-the-road (OTR) tires, truck tires, or motorcycle tires. The tires may also be radial or bias tires.

[0058] In a fourth aspect, the present invention provides a method for producing a rubber composition, comprising the steps of: A. For example, in a first step, a diphenol (i.e., pre-reacted) is reacted with an amine, in particular a primary amine, in the presence of an aldehyde derivative (preferably formaldehyde) to obtain a benzoxazine, wherein the diphenol contains a bridge linking or connecting both phenolic groups of the diphenol, said bridge linking at least one of its ends in the meta position of each phenolic group, B. mixing the benzoxazine with the elastomer and filler; C. mixing the elastomer and filler in a second step; D. adding benzoxazine in a third step (including the option of continuing the mixing of step B while adding benzoxazine in step C); E. Curing the Rubber Composition The present invention is directed to a method, comprising one or more of:

[0059] Further steps may be added between the steps listed above. The features and / or embodiments of the above aspects may be combined with each other. The structure, operation, and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings. [Brief explanation of the drawings]

[0060] [Figure 1] 1 is a schematic cross-sectional view of a tire including a rubber component having a rubber composition according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0061] FIG. 1 is a schematic cross-sectional view of a tire 1 according to an embodiment of the present invention. The tire 1 has multiple tire components, such as a tread 10, an inner liner 13, a belt including four belt plies 11, a carcass ply 9, two sidewalls 2, and two bead regions 3, a bead filler apex 5, and beads 4. The exemplary tire 1 is suitable for mounting on the rim of a vehicle, such as a truck or passenger car. As shown in FIG. 1, the belt ply 11 may be covered by an 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 of which connects to one of the beads 4. Each of the axial end portions 6 of the carcass ply 9 can be turned around a respective bead 4 to a position that anchors the axial end portion 6. The turnup portion 6 of the carcass ply 9 can engage with the axially outer surfaces of two flippers 8 and the axially inner surfaces of two chippers 7, which are also considered tire components. As shown in FIG. 1 , the exemplary tread 10 has circumferential grooves 20, each groove 20 may essentially define a U-shaped opening of the tread 10. A major portion of the tread 10 may be formed from one or more tread compounds. Additionally, the grooves 20, particularly the bottoms and / or sidewalls of the grooves 20, may be reinforced with a rubber compound having a higher hardness and / or stiffness than the remainder of the tread compound. Such reinforcement may be referred to herein as groove reinforcement.

[0062] 1 suggests multiple tire components, including, for example, an apex 5, a chipper 7, a flipper 8, and an overlay 12, such additional components are not required by the present invention. Also, the turned-up ends of the carcass ply 9 are not required by the present invention, or may pass on opposite sides of the bead area 3 and terminate axially inward of the bead 4 instead of axially outward of the bead 4. The tire may also have a different number of grooves than, for example, grooves 20, such as fewer than four.

[0063] One or more of the above tire components are made from a rubber composition according to an embodiment of the present invention, which comprises a benzoxazine based on the reaction of i) a diphenol comprising two phenolic groups and a bridge covalently linking the two phenolic groups, ii) an aldehyde derivative, and iii) an amine, wherein the bridge connects at least one phenolic group at the meta position of said at least one phenolic group.

[0064] In a first embodiment, such a rubber composition has the following structure:

[0065] [ka]

[0066] The compound may include 3,3'-dihydroxydiphenyldisulfide-furfurylamine having the formula: In this molecule according to structure (I), a disulfide bridge connects both phenyl groups at the meta position, leaving each para position vacant.

[0067] In another preferred embodiment, the benzoxazine has the following structure II:

[0068] [ka]

[0069] The compound is 3,3'-dihydroxydiphenyl disulfide ethanolamine, as shown in In structure II, the sulfur bridge similarly connects the phenyl group at the meta position. In yet another embodiment, the benzoxazine is 3,3'-dihydroxydiphenyl disulfide aniline, as shown in structure III below.

[0070] [ka]

[0071] Our extensive testing has shown that the 4,4'-benzoxazine configuration, by providing a bridge at the para position of the phenyl groups, provides weaker reinforcement than when the bridge is attached to at least one of the phenyl groups at the meta position.

[0072] For example, the present inventors also tested the following structures (IV) and (V), which are not according to the present invention.

[0073] [ka]

[0074] Structure IV, which is not in accordance with the present invention, represents bis(4-hydroxyphenyldisulfide furfurylamine), in which the disulfide bridges both phenyl groups in the para position.

[0075] [ka]

[0076] Structure V, also not in accordance with the present invention, is bisphenol A furfurylamine, in which the bridge (ie, dimethylmethane) is also coupled at the para position of the phenyl group.

[0077] Table 1 below shows examples of diene-based rubber compositions with different reinforcing agents, including, among others, Structures I, II, III, IV, and V. Control Sample 1 is reinforced essentially with carbon black alone. Control Sample 2 is reinforced with carbon black and a reactive resin system including a phenolic resin and hexamethylenetetramine. Examples 1-3 are reinforced with 3,3'-dihydroxydiphenyldisulfide-furfurylamine (also referred to herein as 3DPDS fa), which corresponds to Structure I shown above. Specifically, Example 1 contains 15 phr of 3DPDS fa (which corresponds to an equimolar amount to the resin content in Control Sample 2), Example 2 contains 10 phr of 3DPDS fa, and Example 3 contains 20 phr of 3DPDS fa.

[0078] [Table 1]

[0079] Table 2 further lists control samples and samples of the invention. In particular, Control Sample 3 is reinforced with bis(4-hydroxyphenyldisulfidefurfurylamine), also referred to herein as 4DPDS fa. This benzoxazine corresponds to Structure IV above, with both phenyl groups bridged at the para position. Control Sample 4 is reinforced with bisphenol A furfurylamine (also listed herein as BAfa) and also includes bridges connecting the phenyl groups at the para position (also see Structure V). In contrast, Examples 4 and 5 also include benzoxazines bridged at the meta position of each phenyl group, where Example 4 is: 3, 3'-dihydroxydiphenyl disulfide ethanolamine (3DPDS ea, also shown in Structure II), and Example 5 contains 3,3'- Dihydroxydiphenyl disulfide aniline (3DPDS, shown in Structure III).

[0080] [Table 2]

[0081] Table 3 shows the measured Young's modulus E, a measure of stiffness, for Control Samples 1-4 and Examples 1-5 corresponding to Tables 1 and 2 above. Control Sample 1, which has only carbon black reinforcement, has the lowest stiffness. Control Samples 3 and 4, reinforced with benzoxazine in which the phenyl group is para-coupled, exhibit higher stiffness than Control Sample 1, but lower stiffness than Control Sample 2, reinforced with an (equimolar) reactive resin. Furthermore, as shown in Table 3, Examples 1-5 each have higher stiffness than any of the control samples and are considered worthy replacements for the reactive resin system of, for example, Control Sample 2. The Young's moduli shown in Table 3 were determined in accordance with DIN 53504 on an Instron 5967 electromechanical testing machine using 75 mm long Type S2 dumbbell specimens. Young's moduli were measured up to a strain of 1.5%.

[0082] [Table 3]

Claims

1. 100 phr of one or more diene-based elastomers, 30 phr to 200 phr of filler, and 5 phr to 40 phr of a benzoxazine that is the reaction product of i) a diphenol containing two phenolic groups and a bridge covalently linking the two phenolic groups, ii) an aldehyde derivative, and iii) an amine. wherein the crosslink connects the two phenolic groups at the meta position of each phenolic group.

2. The rubber composition of claim 1, wherein the amine is a primary amine.

3. the primary amine is selected from the group of aromatic amines, aliphatic amines, cycloaliphatic amines and heterocyclic amines; and / or wherein the primary amine is selected from the group consisting of ethanolamine, allylamine, methylamine, ethylamine, propylamine, butylamine, isopropylamine, hexylamine, cyclohexylamine, 2-aminofluorene, aminophenylacetylene, propargyl ether aniline, 4-aminobenzonitrile, furfurylamine and aniline; The rubber composition according to claim 2.

4. The rubber composition of claim 2, wherein the primary amine is selected from aliphatic amines, and the aliphatic amines contain a carbon chain of less than 18 carbon atoms.

5. The aldehyde derivatives include formaldehyde, paraformaldehyde, polyoxymethylene, and substituted or unsubstituted aliphatic C alkyl groups of the formula RCHO, where R is a heteroatom or no heteroatom. １ -C ２０ 5. The rubber composition according to claim 1, wherein the aldehyde is selected from the group of aldehydes having the formula:

6. 6. The rubber composition of claim 1, wherein the crosslinks include one of aromatic groups, aliphatic groups, cycloaliphatic groups, heterocyclic groups, hexafluoropropane groups, monosulfides, oxygen groups, sulfone groups, and disulfides.

7. A rubber composition according to any one of claims 1 to 6, characterized in that the diphenols are selected from 3,3'-dihydroxydiphenyl disulfides.

8. The benzoxazine has the following structure: 【Chemical 1】 [In the formula, R １ and R ２ is selected from aromatic groups, aliphatic groups, alicyclic groups, and heterocyclic groups; R ３ is an aromatic group, an aliphatic group, an alicyclic group, a heterocyclic group, hexafluoropropane, a monosulfide, or a disulfide. The rubber composition according to claim 1 , characterized in that it comprises at least one of the following:

9. R １ and R ２ is selected from the group consisting of ethanol, allyl, methyl, ethyl, propyl, isopropyl, hexyl, cyclohexyl, fluorene, phenylacetylene, propargyl ether benzyl, benzonitrile, furfuryl and benzyl groups; and / or R ３ is a disulfide; The rubber composition according to claim 8.

10. 10. The rubber composition according to claim 1, which is a sulfur-vulcanizable rubber composition containing a sulfur donor.

11. The filler comprises one or more of silica, carbon black, aluminum hydroxide, ultra-high molecular weight polyethylene, and syndiotactic polybutadiene. The rubber composition according to any one of claims 1 to 10.

12. 12. The rubber composition of claim 1, which is a sulfur vulcanizable rubber composition comprising less than 2 phr of methylene donor and less than 5 phr of methylene acceptor.

13. 13. The rubber composition of claim 1, further comprising at least one second benzoxazine based on the reaction of a phenol and a primary amine, said second benzoxazine optionally being one or more of a monofunctional benzoxazine and a main-chain benzoxazine.

14. A rubber product comprising the rubber composition according to any one of claims 1 to 13.

15. characterised in that the rubber product is selected from the group consisting of tires (1), power transmission belts, hoses, trucks, air sleeves and conveyor belts, or The rubber product is a tire (1) comprising one or more rubber components selected from a tread (10), a shear band, a rubber spoke, an undertread, a sidewall (2), an apex (5), a flipper, a chipper, a chafer, a carcass, a belt, and an overlay, wherein one or more of the rubber components comprises the rubber composition. The rubber product according to claim 14.

16. A method for producing a rubber composition, comprising: reacting a diphenol with an amine in the presence of an aldehyde derivative to obtain a benzoxazine, wherein the diphenol comprises a bridge connecting both phenolic groups of the diphenol, the bridge being connected at each end to the meta position of each of the phenolic groups; and mixing the benzoxazine with an elastomer and a filler to obtain a rubber composition, wherein the rubber composition comprises 100 phr of the elastomer, 30 phr to 200 phr of the filler, and 5 phr to 40 phr of the benzoxazine; A method comprising:

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