Compound, rubber blend containing the compound, vehicle tire containing the rubber blend in at least one component, method for producing the compound, and use of the compound as an anti-aging agent and / or antioxidant

Abstract

The present invention relates to a compound, a rubber blend containing said compound, a vehicle tire comprising said rubber blend as at least one component, a process for the preparation of said compound, and the use of said compound as an ageing protectant and / or antioxidant. JPEG2024544581000014.jpg35170.

Description

Technical Field

[0001] The present invention relates to a compound, a rubber mixture containing the compound, a vehicle tire including the rubber mixture in at least one component, a method for producing the compound, and the use of the compound as an anti-aging agent and / or antioxidant.

Background Art

[0002] It is known that vehicle tires and technical rubber articles employ high molecular materials such as rubber in particular.

[0003] In the case of long-term storage, and especially in intended uses that are often at high temperatures, not only natural rubber and synthetic polymers (such as IR, BR, SBR, ESBR, etc.), but also natural and synthetic oils, fats, and lubricants are subject to oxidation reactions that adversely affect their original desired properties. Depending on the type of polymer, the polymer chains become shorter until the material liquefies or subsequent hardening of the material occurs.

[0004] Therefore, anti-aging agents play a decisive role in the durability of vehicle tires and other technical rubber articles.

[0005] Known anti-aging agents are aromatic amines, such as 6-PPD (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine), IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine) or SPPD (N-(1-phenylethyl)-N'-phenyl-p-phenylenediamine).

[0006] These molecules are reactive with oxygen or ozone, or free radicals such as alkyl, alkoxy, and alkylperoxy radicals that are formed, thereby scavenging them and thus protecting rubber, etc. from further oxidation reactions.

[0007] However, the drawback of this class of substances is that they are suspected of being carcinogenic.

[0008] In particular, an anti-aging stabilizer that reacts with ozone to achieve its scavenging is also called an "anti-ozonant".

SUMMARY OF THE INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0009] An object of the present invention is to provide a novel compound that can be used as an anti-aging stabilizer for vehicle tires or other technical rubber articles, and in particular, has a lower potential risk in combination with sufficient solubility in each matrix, for example, especially in polymers. This is intended to continue to provide optimal protection from oxygen and ozone and prevent the tendency of blooming while reducing harmfulness to health.

MEANS FOR SOLVING THE PROBLEM

[0010] This object is achieved by the compound of the present invention according to claim 1, by the rubber mixture of the present invention containing the compound, and also by the vehicle tire of the present invention containing the rubber mixture of the present invention in at least one component. This object is further achieved by a method for producing the compound and by the use of the compound as an anti-aging stabilizer and / or antioxidant and / or anti-ozonant.

[0011] The compound according to claim 1 has the general formula I):

CHEMICAL FORMULA

[0012] Therefore, the compound of formula I) is N-(1,3-dimethylbutyl)-9H-carbazol-3-amine, or alternatively 3-(1,3-dimethylbutylamino)-9H-carbazole according to another name.

[0013] The compounds according to the invention exhibit an aging stabilization effect similar to 6PPD in rubber mixtures, and thus are suitable as alternatives to 6PPD, the degradation products of which are highly toxic to coho salmon and thus presumably also highly toxic to other aquatic organisms.

[0014] Surprisingly, the compounds according to the invention also exhibit very good solubility in rubber mixtures, especially in vehicle tires and other technical rubber articles, which is presumably due to the 1,3-dimethylbutyl group on the nitrogen atom. However, the invention is not restricted to a specific mechanism of action or a specific theory.

Embodiments for Carrying Out the Invention

[0015] The invention includes all advantageous embodiments, especially those reflected in the claims. The invention also includes embodiments resulting from combinations of different features having different priorities for these features, especially combinations of a first feature described as "preferred" in the context of the invention or in the context of an advantageous embodiment, and a further feature described, for example, as "particularly preferred".

[0016] The compounds of formula (I) of the invention are particularly suitable as anti-aging agents and / or anti-ozonants in vehicle tires and / or other technical rubber articles, such as air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, tactile sensors for medical use or robotics, or soles of shoes or parts thereof, and / or in oils and / or lubricants.

[0017] The compounds according to formula (I) of the invention are particularly suitable for the manufacture of rubber articles such as air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, tactile sensors for medical use or robotics, or soles of shoes or parts thereof.

[0018] For the use of the compound of formula (I) in the article or substance mentioned, said compound is used in a composition and incorporated into said composition for use.

[0019] In vehicle tires or other technical rubber articles, said composition is especially in a rubber mixture.

[0020] The present invention further provides for the use of the compound of the invention of formula (I) in oils, lubricants, especially fuels or engine fluids. Thus, the compounds according to the invention can be employed especially in engines.

[0021] As described above, the present invention further provides a rubber mixture.

[0022] The rubber mixture according to the invention contains a compound of formula (I). The rubber mixture according to the invention can in principle be any rubber mixture in which the novel compound of the invention of formula (I) acts as an anti-aging agent and / or anti-ozonant, especially with low toxicity.

[0023] The rubber mixture of the invention contains at least one rubber.

[0024] Preferably, the rubber mixture according to the invention contains the compound of formula (I) in an amount of 0.1 to 10 phr, particularly preferably 0.1 to 6 phr, very particularly preferably 1 to 5 phr.

[0025] The unit "phr" (parts per 100 parts by weight of rubber) used in this written text is a conventional indication of the amount in a mixture formulation in the rubber industry. The dosage in parts by weight of the individual substances is, in this document, based on 100 parts by weight of the total mass of all high molecular weight (M w exceeding 20,000 g / mol) rubber.

[0026] In an advantageous embodiment of the invention, the rubber mixture according to the invention contains at least one diene rubber.

[0027] Thus, the rubber mixture may contain a diene rubber or a mixture of two or more different diene rubbers.

[0028] A diene rubber is a rubber formed by polymerizing or copolymerizing a diene and / or a cycloalkene, and thus has a C=C double bond either in the main chain or in a side group.

[0029] The diene rubber is preferably natural polyisoprene (NR), synthetic polyisoprene (IR), epoxidized polyisoprene (ENR), butadiene rubber (BR), butadiene-isoprene rubber, solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene-butadiene rubber (ESBR), styrene-isoprene rubber, a liquid rubber with a molecular weight M w exceeding 20,000 g / mol, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluororubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile-butadiene rubber, and hydrogenated styrene-butadiene rubber, and is selected from the group consisting of these.

[0030] Nitrile rubber, hydrogenated acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber, and / or ethylene-propylene-diene rubber are particularly used in the manufacture of technical rubber articles such as belts, drive belts, and hoses and / or shoe soles. It is preferable to employ a mixing composition known to those skilled in the art for these rubbers, which is specific from the viewpoints of fillers, plasticizers, vulcanization systems, and additives.

[0031] The natural and / or synthetic polyisoprene of all embodiments may be cis-1,4-polyisoprene or 3,4-polyisoprene. However, it is preferred to use cis-1,4-polyisoprene having a cis-1,4 ratio of more than 90% by weight. First, such polyisoprene is obtainable by stereospecific polymerization in solution with a Ziegler-Natta catalyst or using a fine lithium alkyl. Second, natural rubber (NR) is such cis-1,4-polyisoprene in which the cis-1,4 content in natural rubber is more than 99% by weight.

[0032] Mixtures of one or more natural polyisoprenes and one or more synthetic polyisoprenes are also further contemplated.

[0033] In the context of the present invention, the term "natural rubber" should be understood to mean natural rubber obtainable from Hevea rubber trees and from "non-Hevea" sources. Non-Hevea sources include, for example, guayule shrubs and dandelions such as TKS (Taraxacum kok-saghyz; Russian dandelion).

[0034] When the rubber mixture of the present invention contains butadiene rubber (i.e., BR, polybutadiene), this may be of any type known to those skilled in the art. These include what are called high-cis and low-cis types, where polybutadiene having a cis content of 90% by weight or more is designated as the high-cis type, and polybutadiene having a cis content of less than 90% by weight is designated as the low-cis type. An example of low-cis polybutadiene is Li-BR (lithium catalyst butadiene rubber) having a cis content of 20% to 50% by weight. In high-cis BR, particularly good properties and low hysteresis are achieved in the rubber mixture.

[0035] The polybutadiene employed may be end-group modified by modification and functionalization, and / or may be functionalized along the polymer chain. The modification may be selected from modification by a hydroxyl group and / or an ethoxy group and / or an epoxy group and / or a siloxane group and / or an amino group and / or an aminosiloxane and / or a carboxyl group and / or a phthalocyanine group and / or a silane-sulfide group. However, further modifications known to those skilled in the art, also referred to as functionalizations, are also useful. A metal atom may be a constituent of such a functionalization.

[0036] If at least one styrene-butadiene rubber (styrene-butadiene copolymer) is present in the rubber mixture, this may be selected from solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR), and it is also possible to employ a mixture of at least one SSBR and at least one ESBR. The terms "styrene-butadiene rubber" and "styrene-butadiene copolymer" are used synonymously in the context of the present invention.

[0037] The styrene-butadiene copolymer used may be end-group modified and / or functionalized along the polymer chain by the modifications and functionalizations mentioned above for polybutadiene.

[0038] At least one diene rubber is preferably selected from the group consisting of natural polyisoprene (NR, natural rubber), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene-butadiene rubber (ESBR), butyl rubber (IIR), and halobutyl rubber.

[0039] In a particularly preferred embodiment of the present invention, at least one diene rubber is selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), and emulsion-polymerized styrene-butadiene rubber (ESBR).

[0040] In a particularly advantageous embodiment of the present invention, the rubber mixture contains at least one natural polyisoprene (NR), preferably in an amount of 50 to 100 phr. In a particularly advantageous embodiment of the present invention, it contains 80 to 100 phr, very particularly preferably 95 to 100 phr, and then preferably 100 phr. Such a rubber mixture exhibits optimized tear and wear characteristics, especially in combination with good processability and recovery stability.

[0041] If the rubber mixture contains less than 100 phr of NR, the rubber mixture preferably contains, as a further rubber, at least one diene rubber selected from the group consisting of synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), and emulsion-polymerized styrene-butadiene rubber (ESBR).

[0042] In a further particular advantageous embodiment of the present invention, the rubber mixture contains at least one natural polyisoprene (NR), preferably in an amount of 5 to 55 phr, and in a particular advantageous embodiment of the present invention, 5 to 25 phr, very particularly preferably 5 to 20 phr. Such a rubber mixture exhibits particularly good processability, vulcanization return stability, optimized tear characteristics, and optimal rolling resistance characteristics.

[0043] In a further particular advantageous embodiment of the present invention, the rubber mixture contains at least one polybutadiene (BR, butadiene rubber), preferably in an amount of 10 to 80 phr, particularly preferably 10 to 50 phr, and in a particular advantageous embodiment of the present invention, 15 to 40 phr. Thereby, particularly good tear and wear characteristics of the rubber mixture according to the present invention, as well as optimal braking characteristics, are achieved.

[0044] In a further specific advantageous embodiment of the present invention, the rubber mixture comprises at least one solution-polymerized styrene-butadiene rubber (SSBR), preferably in an amount of 10 to 80 phr, particularly preferably in an amount of 30 to 80 phr, and in a particularly advantageous embodiment of the present invention, in an amount of 50 to 70 phr. Thereby, particularly good rolling resistance characteristics of the rubber mixture according to the present invention are achieved. In a particularly advantageous embodiment of the present invention, the SSBR is employed in combination with at least one further rubber in order to achieve an optimal and well-balanced property profile.

[0045] Preferably, the rubber mixture contains at least one filler, preferably in an amount of 30 to 500 phr, particularly preferably in an amount of 50 to 400 phr, and then preferably in an amount of 80 to 300 phr.

[0046] In an advantageous embodiment of the present invention, the filler is preferably a reinforcing filler selected from the group consisting of carbon black and silicon dioxide.

[0047] Suitable carbon blacks include any carbon black type known to those skilled in the art. Preferably, the carbon black is selected from industrial carbon black and pyrolytic carbon black, and more preferably industrial carbon black.

[0048] The carbon black has an iodine number according to ASTM D1510, which is also known as the iodine adsorption amount of 30 to 250 g / kg, preferably 30 to 180 g / kg, particularly preferably 40 to 180 g / kg, and even more particularly preferably 40 to 130 g / kg, and a DBP value according to ASTM D2414 of 30 to 200 ml / 100 g, preferably 70 to 200 ml / 100 g, particularly preferably 90 to 200 ml / 100 g.

[0049] The DBP value according to ASTM D2414 determines the specific absorption volume of the carbon black or light-colored filler with respect to dibutyl phthalate.

[0050] The use of such types of carbon black in a rubber mixture, especially for vehicle tires, ensures an optimal compromise between wear resistance and heat storage, which in turn affects the ecologically relevant rolling resistance.

[0051] Particularly suitable and preferred carbon blacks are those having an iodine adsorption number of 80 to 110 g / kg and a DBP number of 100 to 130 ml / 100 g, such as in particular carbon black of type N 339.

[0052] Silicon dioxide is preferably amorphous silicon dioxide, such as precipitated silica, also known as precipitated silica. However, it is also alternatively possible to use, for example, pyrogenic silicon dioxide.

[0053] However, it is particularly preferred to use ground precipitated silica having a nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132) of 35 to 400 m2 / g, preferably 35 to 350 m2 / g, more preferably 85 to 320 m2 / g, most preferably 120 to 235 m2 / g and a CTAB surface area (according to ASTM D 3765) of 30 to 400 m2 / g, preferably 30 to 330 m2 / g, more preferably 80 to 300 m2 / g, most preferably 115 to 200 m2 / g. Such silica provides particularly good physical properties of the vulcanized rubber, for example, in a rubber mixture for a tire tread. It is also possible to achieve advantages in the processing of the mixture by shortening the mixing time while maintaining the same product properties, resulting in improved productivity. The silica used may thus be, for example, Ultrasil® VN3 type (trade name) from Evonik, or highly dispersed silica known as HD silica (for example, Zeosil® 1165 MP from Solvay).

[0054] In a particularly advantageous embodiment of the present invention, the rubber mixture contains, as a filler, at least one silica, preferably in an amount of 30 to 500 phr, particularly preferably in an amount of 50 to 400 phr, and then preferably in an amount of 80 to 300 phr.

[0055] In these amounts, the silica is present in particular as the sole or main filler (more than 50% by weight based on the total amount of fillers).

[0056] In a further advantageous embodiment of the present invention, the rubber mixture contains at least one silica as a further filler, preferably in an amount of 5 to 100 phr, particularly preferably in an amount of 5 to 80 phr, and then preferably in an amount of 10 to 60 phr.

[0057] In these amounts, the silica is present in particular as a further filler in addition to other main fillers such as carbon black in particular.

[0058] The terms "silicic acid" and "silica" are used synonymously in the context of the present invention.

[0059] In a particularly advantageous embodiment of the present invention, the rubber mixture according to the present invention contains at least one carbon black in an amount of 0.1 to 60 phr, preferably 3 to 40 phr, particularly preferably 5 to 30 phr, and very particularly preferably 5 to 15 phr. In these amounts, the carbon black is present in particular as a further filler in addition to main fillers such as silica in particular.

[0060] In a further advantageous embodiment of the present invention, the rubber mixture according to the present invention contains at least one carbon black in an amount of 30 to 300 phr, preferably 30 to 200 phr, particularly preferably 40 to 100 phr. In these amounts, the carbon black is present alone or as the main filler, and optionally in combination with silica in the amounts on the lower limit side described above.

[0061] In certain advantageous embodiments of the present invention, the rubber mixture contains at least one carbon black in an amount of 5 to 60 phr, particularly preferably 5 to 40 phr, and at least one silica in an amount of 50 to 300 phr, preferably 80 to 200 phr.

[0062] The rubber mixture may further contain a reinforcing or non-reinforcing additional filler.

[0063] In the context of the present invention, additional (non-reinforcing) fillers include aluminosilicates, kaolin, chalk, starch, magnesium oxide, titanium dioxide, or rubber gels and fibers (such as aramid fibers, glass fibers, carbon fibers, cellulose fibers).

[0064] Furthermore, optionally, the reinforcing filler includes carbon nanotubes (CNTs), graphite, and graphene, and so-called "carbon silica dual-phase fillers", such as discrete CNTs, so-called hollow carbon fibers (HCF), and modified CNTs containing one or more functional groups such as hydroxyl, carboxyl, and carbonyl groups.

[0065] In connection with the present invention, zinc oxide is not included in the filler.

[0066] The rubber mixture can further contain customary additives in customary parts by weight, which are preferably added in at least one primary mixing stage during the production of the mixture. These additives include: a) Aging stabilizers known in the prior art, For example, p-phenylenediamine, such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N-(1-phenylethyl)-N'-phenyl-p-phenylenediamine (SPPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditoly-p-phenylenediamine (DTPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine (7PPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), or dihydroquinoline, such as 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), b) Activators such as zinc oxide and fatty acids (e.g., stearic acid), and / or other activators such as zinc ethylhexanoate, c) Activators and / or agents for binding fillers, especially carbon black or silica, such as S-(3-aminopropyl) thiosulfate and / or its metal salts (for binding carbon black) and silane coupling agents (for binding silica), d) Antiozonant wax, e) Resins, especially tackifying resins, f) Kneading aids such as 2,2'-dibenzamidodiphenyl disulfide (DBD), and g) Processing aids, especially fatty acid esters and metal soaps, such as zinc soap and / or calcium soap, h) Plasticizers, such as especially aromatic, naphthenic or paraffinic mineral oil plasticizers, such as MES (mild extraction solvent neutral), preferably having a content of polycyclic aromatic compounds of less than 3% by weight according to method IP 346, or RAE (residual aromatic extract), or TDAE (treated distillate aromatic extract) or rubber to liquid (RTL) oil or biomass to liquid (BTL) oil, or triglycerides, such as rapeseed oil or factice or hydrocarbon resins or liquid polymers having an average molecular weight (measured by GPC = gel permeation chromatography in accordance with BS ISO 11344:2004) of 500 to 20,000 g / mol.

[0067] When using mineral oil, this is preferably selected from the group consisting of DAE (distillate aromatic extract), RAE (residual aromatic extract), TDAE (treated distillate aromatic extract), MES (mild extract solvate), and naphthenic oil.

[0068] In a particularly advantageous embodiment, the rubber mixture according to the invention, in addition to the compound of the invention of formula I), does not contain an anti-aging stabilizer from the group of p-phenylenediamines, in particular those listed above in a). In a particularly preferred embodiment, the rubber mixture according to the invention contains further anti-aging stabilizers in an amount of 0 to 0.1 phr, in particular 0 phr, based on p-phenylenediamine, which is selected from the group consisting of N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N-(1-phenylethyl)-N'-phenyl-p-phenylenediamine (SPPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditoly-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine (7PPD), preferably consisting of this group.

[0069] Preferably very small amounts of 0 to 0.1 phr, particularly preferably 0 phr, of the p-phenylenediamines mentioned, and the compound of formula I) present according to the invention make it possible to achieve an equivalent protective effect with lower toxicity. The compound of formula I) of the invention replaces the mentioned p-phenylenediamines known in the prior art.

[0070] In a further advantageous embodiment of the invention, since at least one further representative of the mentioned p-phenylenediamine anti-aging stabilizer is present, the compound according to the invention only partially replaces the p-phenylenediamines known in the prior art. This also achieves the advantages according to the invention, although not to the optimum extent.

[0071] In an advantageous embodiment, a dihydroquinoline-based anti-aging agent such as TMQ is present in the rubber mixture in addition to the compound of formula (I) according to the invention. In particular, the amount of dihydroquinoline present, such as TMQ, is preferably from 0.1 to 3, in particular from 0.5 to 1.5 phr.

[0072] The antiozonant waxes (group d above) are considered separately and, in a preferred embodiment of the invention, are present in the rubber mixture regardless of whether additional anti-aging agent a) is present.

[0073] The silane coupling agents are of any type known to the person skilled in the art.

[0074] Furthermore, one or more different silane coupling agents can be used in combination with each other. For this purpose, the rubber mixture can contain a mixture of different silanes.

[0075] The silane coupling agent reacts with the surface silanol groups or other polar groups of silicon dioxide, in particular silica, either before the addition of the filler to the rubber or during the mixing of the rubber / rubber mixture (in situ) or in the context of a pretreatment (pre-modification).

[0076] Coupling agents known from the prior art are bifunctional organosilanes having at least one alkoxy, cycloalkoxy or phenoxy group as a leaving group on the silicon atom and possibly, after cleavage, having another functional group capable of undergoing a chemical reaction with the double bonds of the polymer. The groups in the latter can include, for example, the following chemical groups: -SCN, -SH, -NH2 or -Sx- (where x = 2 to 8).

[0077] Possible silane coupling agents include, for example, 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane or 3,3'-bis(triethoxysilylpropyl) polysulfide having 2 to 8 sulfur atoms, such as 3,3'-bis(triethoxysilylpropyl) tetrasulfide (TESPT), the corresponding disulfide (TESPD), or other mixtures of sulfides with various sulfides having different contents and having 1 to 8 sulfur atoms. TESPT can also be added, for example, as a mixture with industrial carbon black (trade name X50S®, manufactured by Evonik).

[0078] For example, blocked mercaptosilanes as known from WO 99 / 09036 can also be used as silane coupling agents. It is also possible to use the silanes described in WO 2008 / 083241 A1, WO 2008 / 083242 A1, WO 2008 / 083243 A1, and WO 2008 / 083244 A1. Usable silanes include, for example, those sold by Momentive in the United States under the name NXT in numerous variants, such as 3-octanoylthio-1-propyltriethoxysilane in particular, or those sold by Evonik Industries under the name VP Si 363®.

[0079] The total proportion of further additives is preferably 3 to 150 phr, more preferably 3 to 100 phr, and most preferably 5 to 80 phr.

[0080] Zinc oxide (ZnO) can be included in the overall proportion of further additives in the amounts described above.

[0081] This may be any type of zinc oxide known to those skilled in the art, such as ZnO granules or powder. Commonly used zinc oxide generally has a BET surface area of less than 10 m2 / g. However, it is also possible to use zinc oxide having a BET surface area of 10 to 100 m2 / g, such as so-called "nanometer zinc oxide".

[0082] The rubber mixture of the present invention is preferably in a vulcanized form and is particularly used for vehicle tires or other vulcanized technical rubber articles.

[0083] The terms "vulcanization" and "crosslinking" are used synonymously in the context of the present invention.

[0084] The vulcanization of the rubber mixture of the present invention is preferably carried out in the presence of sulfur and / or a sulfur donor, with the assistance of a vulcanization accelerator, and some vulcanization accelerators can act as sulfur donors simultaneously. The vulcanization accelerators are selected from the group consisting of thiazole vulcanization accelerators, mercapto vulcanization accelerators, sulfenamide vulcanization accelerators, thiocarbamate vulcanization accelerators, thiuram vulcanization accelerators, thiophosphate vulcanization accelerators, thiourea vulcanization accelerators, xanthate vulcanization accelerators, and guanidine vulcanization accelerators.

[0085] N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), It is preferable to use a sulfenamide accelerator selected from guanidine accelerators such as N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS), benzothiazyl-2-sulfenmorpholide (MBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), and diphenylguanidine (DPG).

[0086] The sulfur donor substance used may be any sulfur donor substance known to those skilled in the art.

[0087] A vulcanization retarder may be present in the rubber mixture.

[0088] In other cases, the production of the rubber mixture according to the invention is carried out by a process customary in the rubber industry, which preferably comprises first producing a primary mixture containing all components except the vulcanization system (e.g., sulfur and vulcanization influencers) in one or more mixing stages. The final mixture is produced by adding the vulcanization system in the final mixing stage.

[0089] The final mixture is, for example, further processed and shaped into a suitable form by an extrusion operation or calendering.

[0090] The rubber mixture according to the invention is particularly suitable for use in vehicle tires, especially pneumatic vehicle tires. In principle, use in all tire components, especially outer components, particularly preferably in the flange profile, tread and / or sidewall, is conceivable. In the case of a tread having a cap / base structure, the rubber mixture according to the invention is preferably used at least within the cap.

[0091] For use in vehicle tires, the mixture as a finished mixture before vulcanization is preferably shaped into the corresponding shape of the outer component and applied in a manner known during the production of green vehicle tires.

[0092] The production of the rubber mixture according to the invention for use as any other body mixture in vehicle tires is carried out as described above. There are differences in the shaping after the extrusion operation / calendering of the mixture. The shape of the as-yet-unvulcanized rubber mixture for one or more different body mixtures thus obtained is then used for the production of green tires.

[0093] Here, the "body mixture" basically refers to rubber mixtures for the inner components of tires such as skids, inner liners (inner layers), core profiles, belts, shoulders, belt profiles, carcasses, bead reinforcements, bead profiles, flange profiles and bands.

[0094] The as-yet-unvulcanized green tire is then vulcanized.

[0095] For the use of the rubber mixture according to the invention in drive belts and other belts, in particular conveyor belts, the extruded, still unvulcanized mixture is given the appropriate shape and reinforcing members, such as synthetic fibers or steel cords, are provided frequently, simultaneously or subsequently. Thereby, a multi-ply structure is usually obtained which consists of one and / or more plies of the rubber mixture, one and / or more plies of the same and / or different reinforcing members, and one and / or more further plies of the same and / or other rubber mixtures.

[0096] The invention further provides a vehicle tire comprising a rubber mixture according to the invention containing a compound according to the invention in at least one component.

[0097] The vulcanized vehicle tire in at least one component contains a vulcanizate of at least one rubber mixture according to the invention. It is known to the person skilled in the art that most substances present, such as rubber, can already be present after mixing or only in a chemically modified form after vulcanization.

[0098] In the context of the present invention, "vehicle tire" is to be understood as meaning pneumatic vehicle tires and solid rubber tires, including industrial tires and tires for construction site vehicles, trucks, cars and two-wheeled vehicles.

[0099] The vehicle tire according to the invention preferably contains a rubber mixture according to the invention in at least one external component, where the external component is preferably the tread, the sidewall and / or the flange profile.

[0100] Accordingly, the vehicle tire according to the invention may contain a rubber mixture according to the invention containing a compound according to formula I) in a plurality of components, optionally in an adapted composition.

[0101] The present invention further provides a process for producing a compound of formula (I), wherein the process comprises at least the following process steps: a1) A substance of formula A1) or A2):

Chemical formula

Chemical formula

[0102] The compound of formula A2) can be produced as described in M. Takagi, Org. Biomol. Chem., 2019, 17(7), 1791 - 1795 and as shown in formula R1):

Chemical formula

[0103] Alternatively, the compound of formula A2) can also be produced by nitrating 9H - carbazole (M. Yu, Supramol. Chem., 2008, 20(4), 357 - 361) as shown in formula R2) and formula R3) to obtain a compound of formula A1), followed by subsequent reduction (M. Takagi, Org. Biomol. Chem., 2019, 17, 1791 - 1795):

Chemical formula

[0104] The compound of formula A1) can further be produced by condensation of the corresponding hydrazine with cyclohexyl ketone and subsequent cyclization / aromatization as shown in formula R4) (B.A. Dalvi, Tet. Lett., 2018, 59, 2145 - 2149):

Chem.

[0105] The "reducing agent" should be understood to mean a compound that enables reduction. As is known to those skilled in the art, such reagents include hydrides, especially metal hydrides.

[0106] Suitable reducing agents are, in particular, hydrides selected from the group consisting of sodium hydride (NaH), calcium hydride (CaH2), sodium borohydride (NaBH4), NaBH3CN, NaBH(OAc)3, and 2-methylpyridine borane complex.

[0107] In the context of the present invention, since hydrogen is explicitly mentioned as an alternative, it is not additionally listed as a "reducing agent". However, it will be understood that the term "reducing agent" encompasses any reagent that forms hydrogen in the system and thereby effects hydrogenation.

[0108] The use of reducing agents other than hydrogen is particularly contemplated when the reaction of step c1) is carried out starting from the compound of formula A2).

[0109] The reaction of step c1) is preferably carried out using hydrogen.

[0110] In the reaction using hydrogen, preferably, a suitable catalyst, which is referred to as a "hydrogenation catalyst" in the context of the present invention, is additionally used.

[0111] The hydrogenation catalyst is preferably a noble metal catalyst such as palladium (Pd) or platinum (Pt) in particular. The noble metal is preferably employed on carbon (C) such as palladium on carbon (Pd / C).

[0112] Furthermore, it is also possible to use other known catalysts such as Raney nickel or copper chromite.

[0113] Therefore, the reaction in step c1) is particularly preferably carried out using hydrogen with a hydrogenation catalyst.

[0114] The reaction in step c1) is preferably carried out at a temperature of 80°C to 150°C, particularly for example 120°C.

[0115] The reaction mixture is preferably pressurized with hydrogen at a pressure of 35 to 45 bar, particularly for example 40 bar, and then preferably stirred for 1 to 20 hours, preferably 3 to 13 hours, particularly preferably 5 to 13 hours, particularly for example 10 hours.

[0116] The reaction with hydrogen in step c1) is preferably carried out, particularly for example, in an autoclave or another pressure reactor, preferably in a container suitable for a relatively high pressure.

[0117] The reaction in step c1) is particularly preferably carried out using a hydrogenation catalyst, at a temperature of 80°C to 150°C, using hydrogen, the reaction mixture is pressurized with hydrogen at a pressure of 25 to 45 bar, and the reaction is carried out in an autoclave or another pressure reactor.

[0118] The solvent in step c1) may be MIBK that functions as a reactant at the same time, or an inert solvent such as toluene or xylene. In the latter case, MIBK is used only in stoichiometric amounts as a reactant. However, it is preferable that MIBK is also used as a solvent at the same time. Thereby, additional substances such as toluene and xylene can be avoided. Furthermore, unreacted MIBK can be recovered and reused after the reaction.

[0119] Preferably, after step c1), purification is carried out, for example, by column chromatography on silica gel.

[0120] As shown, the reaction in step c1) can be carried out starting from either the compound of formula A1) or the compound of formula A2).

[0121] However, in step c1), it is preferable to directly convert the compound of formula A1) with hydrogen and MIBK. Thereby, a relatively high yield is achieved.

[0122] Hereinafter, the present invention will be made more specifically clear with reference to examples.

Examples

[0123] The compound of formula I) was produced as follows according to the first synthetic route as represented by Scheme X1):

Chemical formula

[0124] Into a stainless steel autoclave equipped with a Teflon inliner, 0.35 g (1.92 mmol, 1 equivalent) of 3-amino-9H-carbazole (compound of formula A2), 0.16 g of palladium on carbon (Pd / C) (5%) (0.4 g per 4.67 mmol of substrate), and 20.0 ml of methyl isobutyl ketone (MIBK) were added. Subsequently, the reaction mixture was pressurized with 40 bar of hydrogen (H2) and stirred at 120 °C for 10 hours. After completion of the reaction, excess hydrogen was vented, the suspension was filtered through Celite® and then washed with ethanol. The filtrate was concentrated until dry and dried under reduced pressure. This substance was purified by silica gel (cyclohexane / ethyl acetate (EA) 10:1): a grayish solid; yield 0.38 g (75% of theory). 1H-NMR (Nuclear Magnetic Resonance) (500 MHz, DMSO-d6) δ = 10.69 (s, 1H), 7.94 (dd, J = 7.7, 1.0 Hz, 1H), 7.36 (d, 8.1 Hz, 1H), 7.27 (ddd, J = 8.2, 7.0, 1.2 Hz, 1H), 7.24 - 7.19 (m, 3H), 7.03 (ddd, J = 7.9, 7.0, 1.0 Hz, 1H), 6.78 (dd, J = 8.5, 2.3 Hz, 1H), 4.75 (d, J = 9.0 Hz, 1H), 3.62 - 3.47 (m, 1H), 1.80 (dp, J = 13.5, 6.7 Hz, 1H), 1.51 (dt, J = 13.8, 7.1 Hz, 1H), 1.25 (dt, J = 13.5, 6.8 Hz, 2H), 1.13 (d, J = 6.1 Hz, 3H), 0.96 (d, J = 6.6 Hz, 3H), 0.91 (d, J = 6.6 Hz, 3H). 13 C-NMR (126 MHz, DMSO-d6) δ = 142.3, 140.6, 132.9, 125.2, 123.6, 122.8, 120.3, 117.9, 115.4, 111.9, 111.2, 102.1, 47.0, 46.7, 25.1, 23.4, 23.1, 21.3. ESI-MS (Electrospray Ionization Mass Spectrometry) [M + H] + = 267. Melting point: 107 °C

[0125] According to a further synthetic route, as shown in Scheme X2), the compound of formula I) was prepared as follows:

Chemical Structure

[0126] A stainless steel autoclave equipped with a Teflon liner was charged with 4.00 g (18.9 mmol, 1 equiv) of 3-nitro-9H-carbazole (compound of formula A1), 1.60 g of platinum on carbon (Pt / C) (5%) (0.4 g per 4.67 mmol of substrate), and 50.0 ml of methyl isobutyl ketone. Subsequently, the reaction mixture was pressurized with 40 bar of hydrogen and stirred at 120 °C for 10 h. After completion of the reaction, the excess hydrogen was vented, the suspension was filtered through Celite®, and subsequently washed with ethanol. The filtrate was concentrated to dryness and dried under reduced pressure. This material was purified by silica gel (cyclohexane / EE 10:1): grayish solid; yield 4.40 g (88% of theory). <905 1 H-NMR, 13 Analysis of the product including C-NMR, ESI-MS, and melting point: same values as in the above reaction according to Scheme X1).

[0127] For use in a rubber mixture for vehicle tires, the compound of the invention of formula I) is added in a manner known to those skilled in the art at one of the mixing stages during the production of the rubber mixture, for example, instead of an anti-aging stabilizer known to those skilled in the art such as 6PPD, 7PPD or IPPD.

[0128] Thus, the compound of formula I) was incorporated in different amounts into the exemplary rubber mixtures according to the invention as shown in Table 1. The obtained examples of the invention are labeled as E1 and E2.

[0129] Rubber mixtures containing 6PPD instead of the compound of formula I) as an anti-aging stabilizer and having the same remaining composition, with V1 and E1 and V2 and E2 being equimolar substituted in each case, were used as a comparison. The amounts in Table 1 are expressed in units of phr. A reference (Ref.) without an anti-aging stabilizer is also reported.

[0130] In all mixtures, the total amount of the anti-aging stabilizer (6PPD or formula I)) and the plasticizer oil MES is 10 phr.

[0131]

Table 1

[0132] Examples of the present invention show no significant decrease in the aging stabilization effect and even show improvement compared to rubber mixtures containing 6PPD. Note that this application relates to the invention described in the claims, but may also include the following as other aspects. 1. Compound of formula (I):

Chem.

Chem.

Chem.

Claims

1. Formula (I): 【Chemical 1】 compound.

2. A rubber mixture containing the compound of formula (I) according to Claim 1.

3. The rubber mixture according to Claim 2, characterized in that it contains at least one diene rubber.

4. The rubber mixture according to Claim 3, characterized in that it contains at least one diene rubber selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene-butadiene rubber (ESBR), butyl rubber (IIR) and halobutyl rubber.

5. A vehicle tire comprising the rubber mixture according to any one of Claims 2 to 4 in at least one component.

6. The vehicle tire according to Claim 5, characterized in that it contains at least one rubber mixture according to any one of Claims 2 to 4 in at least one external component.

7. The vehicle tire according to Claim 6, characterized in that the external component is a tread, a sidewall and / or a flange profile.

8. A process for preparing the compound of formula (I) according to Claim 1, comprising at least the following processing steps: a1) A substance of formula (A1) or (A2): 【Chemical 2】 preparing step; b1) preparing methyl isobutyl ketone (MIBK) and hydrogen or a reducing agent; c1) reacting the compound of formula (A1) or formula (A2) with the substances from step b1) to obtain the compound of formula (I) 【Chemical Formula 3】 obtaining step; method comprising.

9. The method according to Claim 8, wherein the reaction in step c1) is carried out using a hydrogenation catalyst and / or using hydrogen at a temperature of 80 °C to 150 °C, and / or the reaction mixture is pressurized with hydrogen at a pressure of 25 to 45 bar, and the reaction is carried out in an autoclave or another pressure reactor.

10. Use of the compound of formula (I) according to Claim 1 as an anti-aging stabilizer and / or an anti-ozone agent in vehicle tires and / or other technical rubber articles.

11. Use of the compound of formula (I) according to Claim 1 as an anti-aging stabilizer and / or an anti-ozone agent in air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, medical or robotic tactile sensors, or soles of shoes or parts thereof, and / or in oils and / or lubricants. Use of a compound of formula (I) according to claim 1 for producing a rubber article. Use of a compound of formula (I) according to claim 1 for producing an air spring, a bellows, a conveyor belt, a belt, a drive belt, a hose, a rubber band, a profile, a seal, a membrane, a tactile sensor for medical use or robotics, or a shoe sole or part thereof. Use of a compound of formula (I) according to claim 1 in an oil or a lubricant. Use of a compound of formula (I) according to claim 1 in a fuel or an engine fluid.

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