Compound, rubber blend containing said compound, vehicle tire containing said rubber blend as at least one component, process for producing said compound, and use of said compound as ageing stabilizer and / or antiozonant and / or dye

Abstract

The present invention relates to a compound, a rubber blend containing said compound, a vehicle tire comprising at least one component of the rubber blend, a process for producing said compound, and the use of said compound as an ageing stabilizer and / or antiozonant and / or dye. The compound according to the invention has formula I: TIFF2024529395000025.tif34170 (wherein R1 is xi) aromatic groups, optionally bearing substituents selected from the group consisting of halogen groups, cyano groups, ester groups, ketone groups, ether groups and thioether groups; and xii) linear, branched and cyclic aliphatic C1-C12 groups; and xiii) a combination of aromatic and aliphatic C1-C12 groups. has.

Description

[Technical Field]

[0001] The present invention relates to a compound, a rubber mixture containing the compound, a vehicle tire comprising the rubber mixture in at least one component, a process for producing the compound, and the use of the compound as an ageing stabilizer and / or antiozonant and / or dye. [Background technology]

[0002] Vehicle tires and technical rubber articles are known to employ polymeric materials, particularly rubber.

[0003] During prolonged storage and, particularly, during intended use, which is often at elevated temperatures, natural rubber and synthetic polymers (such as IR, BR, SSBR, ESBR, etc.), as well as natural and synthetic oils, fats, and lubricants, undergo oxidation reactions that adversely affect their inherently desirable properties. Depending on the type of polymer, the polymer chains shorten until the material liquefies or until subsequent hardening of the material occurs.

[0004] Aging stabilizers therefore play a crucial role in the durability of vehicle tires and other technical rubber articles.

[0005] Known ageing stabilizers 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 capable of reacting with oxygen or ozone or with the free radicals formed, such as alkyl, alkoxy and alkylperoxy radicals, thereby scavenging them and thus protecting the rubber etc. from further oxidation reactions.

[0007] However, a drawback of this substance class is that they are suspected to be carcinogenic.

[0008] Aging stabilizers that specifically react with ozone to achieve its scavenging are also called "antiozonants." Summary of the Invention [Problem to be solved by the invention]

[0009] The object of the present invention is to provide novel compounds that can be used in particular as ageing stabilizers for vehicle tires or other industrial rubber articles, and that are less potentially hazardous, in particular in combination with sufficient solubility in the respective matrix, for example in particular in polymers, with the intention of preventing the tendency to blooming while maintaining optimal protection from oxygen and ozone and reducing the hazard to health. [Means for solving the problem]

[0010] This object is achieved by the compounds according to the invention as claimed in claim 1, by rubber mixtures according to the invention which contain the compounds, and by vehicle tyres according to the invention which contain rubber mixtures according to the invention in at least one of their components.

[0011] This object is further achieved by using the compounds as ageing stabilizers and / or antiozonants.

[0012] The compounds according to claim 1 may further be used as dyes.

[0013] This object is further achieved by the process according to the invention for preparing the compounds according to the invention.

[0014] The compound of claim 1 has the general formula I): [ka] (In the formula, R 1 teeth, xi) an aromatic radical, which may have a substituent selected from the group consisting of a halogen radical, a cyano radical, an ester radical, a ketone radical, an ether radical, and a thioether radical; and xii) linear, branched and cyclic aliphatic C1-C 12 radicals, and xiii) aromatic and aliphatic C1-C 12 a combination of radicals selected from the group consisting of: R 2 is a linear, branched, and cyclic, saturated, and unsaturated aliphatic C1-C optionally having one or more halogen substituents; 12 radicals, aryl radicals which may have one or more halogen substituents, halogen radicals, preferably fluorine, bromine and chlorine, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radical R 2 are independently the same or different; and R 3 is a linear, branched, and cyclic, saturated, and unsaturated aliphatic C1-C optionally having one or more halogen substituents; 12 radicals, aryl radicals which may carry one or more halogen substituents, halogen radicals, of which fluorine, bromine and chlorine are preferred, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals, wherein n takes the value 0 or 1.

[0015] R 1 benzyl and straight-chain, branched-chain and cyclic aliphatic C1-C 12 - radicals; R 2 is a linear, branched and cyclic aliphatic C1-C 12radicals, and aryl radicals, cyano radicals, halogen radicals, with fluorine, bromine and chlorine being preferred, ether radicals and thioether radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radical R 2 are independently the same or different; and R 3 is a linear, branched and cyclic aliphatic C1-C 12 radicals, and aryl radicals, cyano radicals, halogen radicals, with fluorine, bromine and chlorine being preferred, ether radicals and thioether radicals, and n takes the value 0 or 1.

[0016] When n is 0 (zero), the hydrogen atom is R 3 It will be apparent to those skilled in the art that when m is 0, 1, or 2, all remaining free positions on the benzene ring of the indole structure are hydrogen atoms.

[0017] Similarly, those skilled in the art will recognize the (R 2 ) m and R 1 It is clear that the representation of the HN bond should be understood to mean that each of these groups can be naturally and simultaneously located in any position on the benzene ring, except for those already excluded by the tetravalency of the carbon atoms of the benzene ring.

[0018] In the context of the present invention, the types "C1-C 12 The reference to a "radical" should be understood to mean a radical having 1 to 12 carbon atoms. Regardless of this, "C1" is also used to describe the position of the most highly oxidized carbon atom / highest priority carbon atom according to the Cahn-Ingold-Prelog (CIP) rules. What is meant in each context will be clear to those skilled in the art.

[0019] The compounds of the present invention are indole derivatives and exhibit lower potential hazards compared to known aniline-based aging stabilizers (potential cleavage products of 6-PPD). Comparison of the safety data sheets of the basic structure aniline and indole reveals that, unlike aniline, indole is neither genotoxic nor mutagenic. This is a crucial advantage, particularly in technical applications such as vehicle tires or other rubber products, where rubber components may be liberated through wear or other degradation processes. Furthermore, the oxidation products of 6-PPD pose a particular risk to coho salmon. Therefore, it should be assumed that this generally applies to aquatic organisms (Tian et al., Science, 2020 Z. Tian, ​​Science, 2021, 371(6525), 185-189).

[0020] In contrast, indole derivatives have been proposed in pharmaceutical compositions or compositions for skin care, as disclosed in US Patent No. 20200339581A1 and JP Patent Publication No. 2004196699A.

[0021] Japanese Patent No. 06147585B2 discloses an indole derivative of formula S1) [ka] In Japanese Patent Publication No. 06147585B2, R 1 and R 2 is defined differently in this case.

[0022] Compared to indole derivatives from the prior art, such as those shown in formula S1), the compounds according to the invention have the advantage that they do not contain vulcanizable groups (such as -SH) that would allow bonding to rubber / polymers. Bonding would result in localized bonding of the molecule and therefore potentially ineffective in remote areas where oxidative stress occurs. Bonding would therefore prevent the molecule from exerting its full protective potential as an aging stabilizer and / or antiozonant. DETAILED DESCRIPTION OF THE INVENTION

[0023] The present invention includes all advantageous embodiments, particularly those reflected in the claims. The present invention also includes embodiments resulting from combinations of different features with different priorities relative to these features, so that the invention also includes combinations of a first feature described as "preferred" or in the context of an advantageous embodiment with a further feature that is, for example, described as "particularly preferred."

[0024] n is 1 and R 3 is preferably selected from aliphatic and aromatic groups having 1 to 10 carbon atoms.

[0025] n is 1 and R 3 It is particularly preferred if R is a cyclic saturated or unsaturated aliphatic or cycloaromatic radical having 5 to 10 carbon atoms. 3 may be a saturated aliphatic or unsaturated aliphatic or aromatic radical which is particularly preferably cyclic.

[0026] R 3 It is very particularly preferred if is selected from the phenyl and cyclohexyl radicals.

[0027] This results in a particularly advantageous solubility of these compounds according to the invention in rubber mixtures, especially in vehicle tires and other industrial rubber articles.

[0028] Radical R 1 teeth, xi) an aromatic radical, which may have a substituent selected from the group consisting of a halogen radical, a cyano radical, an ester radical, a ketone radical, an ether radical, and a thioether radical; and xii) linear, branched and cyclic aliphatic C1-C 12 radicals, and xiii) aromatic and aliphatic C1-C 12 The radicals are selected from the group consisting of:

[0029] An aromatic radical from subgroup xi) is, for example, preferably a phenyl radical.

[0030] The aromatic radicals of subgroup xi) may bear substituents.

[0031] As mentioned above, these are selected from the group consisting of halogen radicals, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals.

[0032] It is preferred if the substituent is selected from the group consisting of an ester radical, a ketone radical, an ether radical and a thioether radical.

[0033] In a preferred embodiment, the aromatic radical is unsubstituted at the two carbon atoms adjacent to the C1 atom, i.e., the carbon atom bonded to the N atom. Therefore, in the case of a benzene ring as the basic structure, it is preferred that there is no substituent at the ortho position relative to the N atom.

[0034] In a further preferred embodiment, the aromatic radicals of subgroup xi) are unsubstituted.

[0035] R 1 is preferably bonded to the nitrogen atom (N) via a tertiary carbon atom. Therefore, the C1 atom is preferably a tertiary carbon atom.

[0036] In the context of the present invention, the term "tertiary carbon atom" should be understood to mean a carbon atom that is bonded to only one hydrogen atom.

[0037] This, compared to secondary and quaternary carbon atoms, results in a particularly good protective effect due to the presence of the compound in rubber mixtures, especially vehicle tires and other industrial rubber articles, thereby providing optimal reactivity, especially in relation to mechanisms related to ageing stabilization, and avoiding undesired side reactions.

[0038] The mixed aromatic and aliphatic radicals of subgroup xiii) are, for example, preferably selected from the group consisting of benzyl and 1-phenylalkyl radicals having a total of 7 to 18 carbon atoms, in particular benzyl and 1-phenylethyl radicals, with 1-phenylalkyl radicals, in particular 1-phenylethyl, being particularly preferred for the tertiary carbon atom.

[0039] In a further advantageous embodiment, R 1 is a branched or cyclic alkyl radical having 3 to 12 carbon atoms, preferably 3 to 8 carbon atoms, where R 1 is particularly preferably selected from the 1,3-dimethylbutyl radical and the cyclohexyl radical, where R 1 is very particularly preferably the 1,3-dimethylbutyl radical.

[0040] This achieves particularly good solubility in rubber mixtures for vehicle tires and other industrial rubber articles.

[0041] Radical R 2 are each independently the same or different and are linear, branched, and cyclic, saturated, and unsaturated aliphatic C1-C groups which may have one or more halogen substituents. 12 radicals, aryl radicals which may carry one or more halogen substituents, halogen radicals, of which fluorine, bromine and chlorine are preferred, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals.

[0042] Enumerated Radicals R 2 may already be attached to the respective benzene ring / precursor thereof, in particular by choosing the appropriate starting material.

[0043] It is preferable if m is 0 (zero).

[0044] In a preferred embodiment, the compound has formula II: [ka] It has the following structure.

[0045] The compounds of formula II) make it possible to achieve optimal protection against oxidation and therefore aging, especially in polymers, and at the same time, as mentioned above, the compounds of formula II) are significantly less harmful to health than, for example, 6-PPD or other representatives of this substance class.

[0046] In a further preferred embodiment, the compound has formula III: [ka] It has the following structure.

[0047] The compounds of formula III) indeed make it possible to achieve further improved protection against oxidation and therefore aging, especially in polymers, and at the same time, as mentioned above, the compounds of formula III) are significantly less harmful to health than, for example, 6-PPD or other representatives of this substance class.

[0048] Therefore, compared to 6-PPD, the compound of formula III) is a better and at the same time less harmful to health and environmentally friendly ageing stabilizer.

[0049] The compounds of the invention of formula I), formula II), formula III) and all the above mentioned are particularly suitable as ageing stabilizers and / or antiozonants in vehicle tyres and / or technical rubber articles, such as air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, tactile sensors for medical applications or robotics, or shoe soles or parts thereof, and / or oils and / or lubricants.

[0050] The present invention therefore further provides the use of the compounds according to the invention as ageing stabilizers and / or antiozonants in vehicle tyres and / or industrial rubber articles, in particular air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, tactile sensors for medical or robotic applications, or shoe soles or parts thereof, and / or oils and / or lubricants.

[0051] To use the compounds of Formula I), Formula II), Formula III), and all of the foregoing in the listed articles or materials, the compounds are used in compositions or incorporated into the compositions.

[0052] In vehicle tires or other industrial rubber articles, the composition is especially present in a rubber mix.

[0053] The present invention further provides the use of the compounds of formula I), formula II), formula III) and all of the above inventive compounds as dyes in fibres and / or polymers and / or paper and / or (decorative) paints and coatings.

[0054] A further aspect of the present invention is a method comprising the steps of: a) a compound of formula A) [ka] providing; b) optionally reacting the compound of formula A) with hydrogen to form a compound of formula B) [ka] obtaining a compound of formula (I); c) reacting a compound of formula A) or formula B) with hydrogen or a hydrogenation reagent, in particular a hydride, and a ketone or aldehyde (R 1 =O), preferably with a ketone, particularly preferably methyl isobutyl ketone, to form a compound of formula I) [ka] obtaining a compound of all of which are compounds of formula I, wherein the radical R 1 , R 2 , R 3 and n and m. Here again, it is preferred if n is 1 and m is 0.

[0055] For example, preferably, the compound provided in step a) is 2-phenyl-5-nitro-1H-indole, which is preferably synthesized from 2-phenyl-1H-indole as described in EP 1571142 and has the formula XI): [ka] (In the formula, as is well known, KNO3 represents potassium nitrate and H2SO4 represents sulfuric acid.) This is shown in simplified form in the reaction scheme below.

[0056] The compound 2-phenyl-1H-indole is commercially available.

[0057] In a preferred embodiment of the present invention, step b) is carried out, preferably when the reaction with hydrogen in step b) is carried out using a hydrogenation catalyst, preferably at room temperature, and the reaction mixture is first subjected to hydrogen, preferably at a pressure of 1.3 to 1.6 bar, in particular, for example, 1.5 bar, and subsequently stirred for 1 to 20 hours, preferably 8 to 13 hours, in particular, for example, 12 hours.

[0058] The reaction with hydrogen in step b) may be carried out in a vessel suitable for relatively high pressures, in particular an autoclave or another pressure reactor, or the hydrogen may be supplied via a balloon above the reaction vessel.

[0059] The reaction of step b) is preferably carried out in a vessel suitable for relatively high pressures, in particular an autoclave or another pressure reactor.

[0060] In a further preferred embodiment of the present invention, the compound of formula A) is reacted according to step c) with hydrogen (H) or a hydrogenation reagent, in particular a hydride, and a ketone or aldehyde (R 1 =O), preferably a ketone, particularly preferably methyl isobutyl ketone, to give the compound of formula I). ​​In the case of hydrogen, it is particularly preferred to use platinum (Pt), preferably on carbon (Pt / C), as catalyst (see below).

[0061] "Hydrogenation reagent" should be understood to mean a compound that brings about hydrogenation. Such reagents include hydrides, in particular metal hydrides, as known to those skilled in the art.

[0062] Suitable hydrides include, for example, sodium borohydride.

[0063] In the context of the present invention, hydrogen is explicitly mentioned as an alternative and is therefore not additionally listed under "hydrogenation reagents". Nevertheless, it will be understood that the term "hydrogenation reagents" encompasses all reagents that form hydrogen to perform in situ hydrogenation.

[0064] R 1 is a cyclohexyl radical, the ketone (R 1 The ketone derivative of (C) is cyclohexanone. The reaction in step c) may be carried out using a hydrogenation reagent, in particular a hydride, such as sodium borohydride, NaBH4, instead of hydrogen. The solvent used is, for example, preferably acetic acid.

[0065] It is preferred if the reaction in step c) with hydrogen and a ketone or aldehyde, preferably a ketone, is carried out using a hydrogenation catalyst, preferably at a temperature of 50° C. to 70° C., in particular for example 60° C. The reaction mixture is preferably subjected to hydrogen at a pressure of 15 to 25 bar, in particular for example 20 bar, and subsequently stirred for preferably 1 to 20 hours, preferably 8 to 13 hours, in particular for example 10 hours.

[0066] In step c), the ketone is reacted with the following radical R 1 In the case of an aldehyde, it is therefore an aldehyde derivative.

[0067] For simplicity, the radical R 1 is the moiety remaining on the nitrogen atom after reaction with an aldehyde or ketone, hence the simplified formula R 1 =O is used for aldehydes or ketones.

[0068] It is preferred to use the ketone methyl isobutyl ketone.

[0069] The reaction with hydrogen in step c) is preferably carried out in a vessel suitable for relatively high pressures, in particular an autoclave or another pressure reactor.

[0070] The solvent in step c) can be either the ketone or aldehyde, if it is in liquid form, or an inert solvent such as toluene or xylene, especially if the ketone or aldehyde is in solid form. In the latter case, the ketone or aldehyde is used only in stoichiometric amounts as a reactant.

[0071] It is preferable to use as solvent a ketone or an aldehyde in liquid form, particularly preferably a ketone, which makes it possible to eject additional substances such as toluene or xylene.

[0072] Preferred are process steps in which the reaction with hydrogen is carried out employing a suitable catalyst, which in the context of the present invention is referred to as a "hydrogenation catalyst".

[0073] It is preferred if the hydrogenation catalyst is a noble metal catalyst, such as, in particular, palladium (Pd) or platinum (Pt). It is preferred if the noble metal is used on carbon (C), such as palladium on carbon (Pd / C).

[0074] Additionally, other known catalysts such as Raney nickel or copper chromite may also be used.

[0075] In the above process, the radical R 3 is preferably a phenyl radical.

[0076] In a preferred embodiment of the invention, step c) is carried out at a temperature of 100° C. or higher, particularly preferably 120° C. or higher, in particular 120° C. to 200° C., for example 120° C., and / or at a hydrogen pressure of more than 25 bar, for example 40 bar, which forms, as a further compound, a compound of formula III) which has particularly advantageous properties as an ageing stabilizer.

[0077] R 3 An alternative route for preparing compounds of the invention of formula I with the variation that R is an aliphatic radical, particularly preferably a cyclohexyl radical. 3 is cyclohexyl (hence n is 1), as shown by the scheme of formula XV. [ka]

[0078] 2-Cyclohexyl-1-indole and its preparation are known, see Zhou et al., Synthesis 2017, 49(16), 3662-3669. It can be nitrated and subsequently subjected to reductive alkylation, preferably in the same manner as the R 1 The preferred hydrogen pressure is 15 to 25 bar, in particular 20 bar. The skilled person is able to adjust the pressure to optionally higher pressures than 25 bar.

[0079] The reaction is preferably carried out in an autoclave or another pressure reactor.

[0080] The route shown therefore represents an alternative process for the preparation of compounds of formula III).

[0081] As mentioned above, the present invention further provides a rubber mixture.

[0082] The rubber mixtures according to the invention contain compounds of formula I), in particular of formula II) and / or III). They can in principle be any rubber mixture in which the novel inventive compounds, in particular of formula I), in particular of formula II) and / or III), act as ageing stabilizers and / or antiozonants with low toxicity.

[0083] The rubber mixtures of the present invention contain at least one rubber.

[0084] It is preferred if the rubber mixtures according to the invention contain 0.1 to 10 phr, particularly preferably 0.1 to 7 phr, very particularly preferably 1 to 6 phr of compounds of the formula I), in particular of the formula II) and / or III).

[0085] The unit "phr" (parts per hundred parts by weight of rubber) used in this document is the conventional indication of quantities for mixture formulations in the rubber industry. The dosage of parts by weight of individual substances is used in this document to refer to all high molecular weight (M) rubbers present in the mixture. w based on 100 parts by weight of the total mass of rubber (whose molecular weight is greater than 20,000 g / mol).

[0086] In an advantageous embodiment of the invention, the rubber mixture according to the invention contains at least one diene rubber.

[0087] Thus, the rubber mixture may contain a diene rubber or a mixture of two or more different diene rubbers.

[0088] Diene rubbers are rubbers formed by polymerizing or copolymerizing dienes and / or cycloalkenes and therefore have C=C double bonds in either the backbone or in side groups.

[0089] 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, molecular weight M w The rubber is selected from the group consisting of liquid rubber having a modulus of more than 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.

[0090] Nitrile rubber, hydrogenated acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber and / or ethylene-propylene-diene rubber are used in particular in the manufacture of industrial rubber articles, such as belts, drive belts and hoses and / or shoe soles, etc. Mixture compositions known to those skilled in the art for these rubbers are preferably employed, which are specific in terms of fillers, plasticizers, vulcanization systems and additives.

[0091] 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 can be obtained by stereospecific polymerization in solution with a Ziegler-Natta catalyst or using finely divided lithium alkyls. 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.

[0092] Mixtures of one or more natural polyisoprenes with one or more synthetic polyisoprenes are also contemplated.

[0093] In the context of the present invention, the term "natural rubber" should be understood to mean natural rubber obtainable from the Hevea rubber tree and from "non-Hevea" sources, such as the guayule shrub and dandelions, such as TKS (Taraxacum kok-saghyz; Russian dandelion).

[0094] When the rubber mixture of the present invention contains butadiene rubber (i.e., BR, polybutadiene), it may be of any type known to those skilled in the art. These include those called high-cis and low-cis types, where polybutadiene having a cis content of 90% by weight or more is called high-cis type, and polybutadiene having a cis content of less than 90% by weight is called low-cis type. An example of low-cis polybutadiene is Li-BR (lithium-catalyzed butadiene rubber) having a cis content of 20% to 50% by weight. With high-cis BR, particularly good properties and low hysteresis are achieved in the rubber mixture.

[0095] The polybutadiene employed may be end-modified and / or functionalized along the polymer chain. The modification may be selected from hydroxyl and / or ethoxy and / or epoxy and / or siloxane and / or amino and / or aminosiloxane and / or carboxyl and / or phthalocyanine and / or silane-sulfide modifications. However, further modifications known to those skilled in the art, also referred to as functionalization, are also useful. Metal atoms may be components of such functionalization.

[0096] If at least one styrene-butadiene rubber (styrene-butadiene copolymer) is present in the rubber mixture, it 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.

[0097] The styrene-butadiene copolymers used may be end-group-modified and / or functionalized along the polymer chain by the modifications and functionalizations mentioned above for polybutadiene.

[0098] The 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.

[0099] In a particularly preferred embodiment of the present invention, the 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).

[0100] In a particularly advantageous embodiment of the invention, the rubber mixture comprises at least one natural polyisoprene (NR) and / or synthetic polyisoprene (IR) in an amount of preferably 50 to 100 phr, in one particularly advantageous embodiment of the invention in an amount of 80 to 100 phr, very particularly preferably 95 to 100 phr, then preferably 100 phr. Such rubber mixtures exhibit in particular optimized tear and wear properties combined with good processability and reversion stability.

[0101] If the rubber mixture contains less than 100 phr of NR and / or IR, the rubber mixture preferably contains as further rubber at least one diene rubber selected from the group consisting of butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR).

[0102] In a further particularly advantageous embodiment of the present invention, the rubber mixture comprises at least one natural polyisoprene (NR), preferably in an amount of 5 to 55 phr, and in one particularly advantageous embodiment of the present invention in an amount of 5 to 25 phr, very particularly preferably 5 to 20 phr. Such rubber mixtures exhibit particularly good processability and reversion stability, as well as optimized tear properties and optimum rolling resistance characteristics.

[0103] In a further particularly advantageous embodiment of the invention, the rubber mixture comprises 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 particularly advantageous embodiment of the invention, 15 to 40 phr, whereby particularly good tear and wear properties and optimal braking characteristics of the rubber mixture according to the invention are achieved.

[0104] In a further particularly 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 30 to 80 phr, and in one particularly advantageous embodiment of the present invention, 50 to 70 phr. This achieves particularly good rolling resistance properties of the rubber mixture according to the present invention. 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 balanced property profile.

[0105] It is preferred if the rubber mixture contains at least one filler, preferably in an amount of 30 to 500 phr, particularly preferably 50 to 400 phr, then preferably 80 to 300 phr.

[0106] In an advantageous embodiment of the invention, the filler is a reinforcing filler preferably selected from the group consisting of carbon black and silicon dioxide.

[0107] Suitable carbon blacks include any carbon black type known to those skilled in the art. It is preferred if the carbon black is selected from technical carbon black and pyrolytic carbon black, with technical carbon black being more preferred.

[0108] The carbon black preferably has an iodine number (also known as iodine adsorption) according to ASTM D1510 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 (DBP) according to ASTM D2414 of 30 to 200 ml / 100 g, preferably 70 to 200 ml / 100 g, and particularly preferably 90 to 200 ml / 100 g.

[0109] The DBP value according to ASTM D2414 determines the specific absorption volume of carbon black or light colored filler relative to dibutyl phthalate.

[0110] The use of such types of carbon black in rubber mixtures, particularly for vehicle tires, ensures an optimal compromise between wear resistance and heat storage, which in turn affects the ecologically relevant rolling resistance.

[0111] 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 type N 339 carbon black.

[0112] The silicon dioxide is preferably amorphous silicon dioxide, for example precipitated silica, also known as precipitated silicon dioxide. However, it is also possible to use, for example, pyrogenic silicon dioxide.

[0113] However, it is particularly preferred to use finely divided precipitated silicas having a nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132) of 35 to 400 m / g, preferably 35 to 350 m / g, more preferably 85 to 320 m / g, and most preferably 120 to 235 m / g, and a CTAB surface area (according to ASTM D 3765) of 30 to 400 m / g, preferably 30 to 330 m / g, more preferably 80 to 300 m / g, and most preferably 115 to 200 m / g. Such silicas, for example in rubber mixtures for tire treads, result in particularly good physical properties of the vulcanized rubber. Advantages in the processing of the mixture due to reduced mixing times can also be obtained while maintaining the same product properties, leading to improved productivity. The silica used can therefore be, for example, Ultrasil® VN3 type (trade name) manufactured by Evonik, or a highly disperse silica known as HD silica (for example Zeosil® 1165MP manufactured by Solvay).

[0114] In a particularly advantageous embodiment of the invention, the rubber mixture contains at least one silica as filler, preferably in an amount of 30 to 500 phr, particularly preferably 50 to 400 phr, then preferably 80 to 300 phr.

[0115] In these amounts, silica is especially present as the sole or primary filler (greater than 50% by weight based on the total amount of filler).

[0116] In a further advantageous embodiment of the invention, the rubber mixture contains at least one silica as further filler, preferably in an amount of 5 to 100 phr, particularly preferably 5 to 80 phr, then preferably 10 to 60 phr.

[0117] In these amounts, the silica is particularly present as an additional filler, especially in addition to other primary fillers such as carbon black.

[0118] The terms "silicic acid" and "silica" are used synonymously in the context of the present invention.

[0119] In a particularly advantageous embodiment of the invention, the rubber mixture according to the invention contains 0.1 to 60 phr, preferably 3 to 40 phr, particularly preferably 5 to 30 phr and very particularly preferably 5 to 15 phr of at least one carbon black. In these amounts, the carbon black is in particular present as a further filler in addition to the main filler, in particular silica.

[0120] In a further advantageous embodiment of the invention, the rubber mixture according to the invention contains from 30 to 300 phr, preferably from 30 to 200 phr, particularly preferably from 40 to 100 phr, of at least one carbon black, in these amounts being present alone or as the main filler, and therefore optionally in combination with silica in the lower amounts mentioned above.

[0121] In a particularly advantageous embodiment of the invention, the rubber mixture contains 5 to 60 phr, particularly preferably 5 to 40 phr, of at least one carbon black and 50 to 300 phr, preferably 80 to 200 phr, of at least one silica.

[0122] The rubber mixture may further contain further fillers, reinforcing or non-reinforcing.

[0123] In the context of the present invention, further (non-reinforcing) fillers include aluminosilicates, kaolin, chalk, starch, magnesium oxide, titanium dioxide, or rubber gels and fibers (e.g. aramid fibers, glass fibers, carbon fibers, cellulose fibers).

[0124] Further, optional reinforcing fillers include, for example, carbon nanotubes (CNTs), such as discrete CNTs, hollow carbon fibers (HCFs), and modified CNTs containing one or more functional groups, such as hydroxy, carboxy, and carbonyl groups), graphite and graphene, and what are known as "carbon-silica dual-phase fillers."

[0125] In the context of the present invention, zinc oxide is not included in the filler.

[0126] The rubber mixture may further contain conventional additives in conventional parts by weight, which are preferably added in at least one primary mixing stage during the preparation of said mixture. These additives include: a) ageing stabilizers known in the art, For example, p-phenylenediamines such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N-(1-phenylethyl)-N'-phenyl-p-phenylenediamine (SPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine (7PPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), or dihydroquinolines, 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 complexes, 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 (carbon black binding) and silane coupling agents (silica binding); d) antiozonant waxes; e) resins, especially tackifying resins; f) mastication aids, such as 2,2'-dibenzamidodiphenyl disulfide (DBD), and g) processing aids, in particular fatty acid esters and metal soaps, for example zinc soap and / or calcium soap, h) plasticizers, such as in particular aromatic, naphthenic or paraffinic mineral oil plasticizers, for example MES (Mild Extraction Solvates), or RAE (Residual Aromatic Extract), or TDAE (Treatment Distillate Aromatic Extract), which preferably have a content of polycyclic aromatic compounds of less than 3% by weight according to method IP 346, or rubber to liquefaction (RTL) oils or biomass to liquefaction (BTL) oils, or triglycerides, for example rapeseed oil or factice, or hydrocarbon resins, or liquid polymers with an average molecular weight (determined by GPC = gel permeation chromatography in accordance with BS ISO 11344:2004) of 500 to 20,000 g / mol.

[0127] If a mineral oil is used, it is preferably selected from the group consisting of DAE (Distillate Aromatic Extract), RAE (Residual Aromatic Extract), TDAE (Treated Distillate Aromatic Extract), MES (Mild Extraction Solvate), and naphthenic oil.

[0128] In a particularly advantageous embodiment, the rubber mixture according to the invention does not contain, in addition to the inventive compounds of formula I), in particular of formula II) and / or III), any ageing stabilizers from the group of p-phenylenediamines, in particular those listed above under a). In a particularly preferred embodiment, the rubber mixture according to the invention contains 0 to 0.1 phr, in particular 0 phr, of further ageing stabilizers based on p-phenylenediamines, preferably 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'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine (7PPD).

[0129] The presence according to the invention of very small amounts of p-phenylenediamine, preferably 0 to 0.1 phr, particularly preferably 0 phr, and of the compounds of formula I), in particular of formula II) and / or III), makes it possible to achieve an equivalent protective effect with lower toxicity.The inventive compounds of formula I), in particular of formula II) and / or III), replace the listed p-phenylenediamines known in the prior art.

[0130] In a further advantageous embodiment of the present invention, at least one further representative of the listed p-phenylenediamine aging stabilizers is present, so that the compounds according to the invention only partially replace the p-phenylenediamines known in the prior art, which also achieve the advantages according to the invention, but only to a less than optimal extent.

[0131] In an advantageous embodiment, an ageing stabilizer of the dihydroquinoline type, such as TMQ, is present in the rubber mixture in addition to the compound of formula I) according to the invention. The amount of dihydroquinoline, in particular TMQ, present is preferably 0.1 to 3, in particular 0.5 to 1.5 phr.

[0132] 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 ageing stabilizers a) are present or not.

[0133] The silane coupling agent may be of any type known to those skilled in the art.

[0134] Additionally, one or more different silane coupling agents may be used in combination with one another, so that a rubber mixture may contain a mixture of different silanes.

[0135] Silane coupling agents react with surface silanol groups or other polar groups of silicon dioxide, especially silica, during mixing of the rubber / rubber mixture (in situ) or in pre-treatment (pre-modification) situations, even before the addition of filler to the rubber.

[0136] Coupling agents known from the prior art are bifunctional organosilanes that have at least one alkoxy, cycloalkoxy or phenoxy group as a leaving group on the silicon atom and other functional groups that, possibly after cleavage, are capable of undergoing chemical reaction with the double bonds of the polymer. The latter groups can include, for example, the following chemical groups: -SCN, -SH, -NH2 or -S x -(where x=2~8).

[0137] Suitable silane coupling agents include, for example, 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane, or 3,3'-bis(triethoxysilylpropyl) polysulfides having 2 to 8 sulfur atoms, such as 3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT), the corresponding disulfides (TESPD), or other mixtures of sulfides having 1 to 8 sulfur atoms with various sulfides of different contents. TESPT can also be added, for example, as a mixture with carbon black (trade name X50S®, manufactured by Evonik).

[0138] For example, blocked mercaptosilanes, such as those known from WO 99 / 09036, can also be used as silane coupling agents. Silanes described in WO 2008 / 083241A1, WO 2008 / 083242A1, WO 2008 / 083243A1, and WO 2008 / 083244A1 can also be used. Usable silanes include, for example, 3-octanoylthio-1-propyltriethoxysilane, sold in many varieties by Momentive USA under the name NXT, or VP Si 363®, sold by Evonik Industries.

[0139] The total proportion of further additives is preferably 3 to 150 phr, more preferably 3 to 100 phr, most preferably 5 to 80 phr.

[0140] Zinc oxide (ZnO) may be included in the overall proportion of further additives in the amounts mentioned above.

[0141] This can be any type of zinc oxide known to those skilled in the art, such as ZnO granules or powder. Conventionally used zinc oxides usually have a BET specific surface area of ​​less than 10 m / g. However, it is also possible to use zinc oxides with a BET surface area of ​​10 to 100 m / g, such as so-called "nano zinc oxide."

[0142] The rubber mixtures of the present invention are preferably used in vulcanized form, especially for vehicle tires or other vulcanized industrial rubber articles.

[0143] The terms "vulcanization" and "crosslinking" are used synonymously in the context of the present invention.

[0144] The vulcanization of the rubber mixtures of the present invention is preferably carried out in the presence of sulfur and / or sulfur donors with the aid of vulcanization accelerators, some of which can simultaneously act as sulfur donors, 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, xanthogenate vulcanization accelerators and guanidine vulcanization accelerators.

[0145] It is preferred to use a sulfenamide accelerator selected from N-cyclohexyl-2-benzothiazolylsulfenamide (CBS), N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS), benzothiazyl-2-sulfen morpholide (MBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), and guanidine accelerators such as diphenylguanidine (DPG).

[0146] The sulfur donor material used can be any sulfur donor material known to those skilled in the art.

[0147] Vulcanization retarders may also be present in the rubber mixture.

[0148] In other cases, the preparation of the rubber mixtures according to the invention is preferably carried out by a process customary in the rubber industry, which involves first preparing a primary mixture in one or more mixing stages, which contains all the components except the vulcanization system (e.g., sulfur and vulcanization-affecting substances), and the final mixture is produced by adding the vulcanization system in the final mixing stage.

[0149] The final mixture may be further processed and shaped, for example, by an extrusion operation or by calendering.

[0150] The rubber mixture according to the invention is particularly suitable for use in vehicle tires, especially pneumatic vehicle tires. In principle, it is conceivable to use it in all tire components, especially outer components, particularly preferably in the flange profile, tread and / or sidewall. In the case of treads with a cap / base structure, it is preferred that the rubber mixture according to the invention is used at least in the cap.

[0151] For use in vehicle tires, the mixture as a finished pre-vulcanization mixture is preferably formed into the corresponding shape of the outer component and applied in known manner during the manufacture of green vehicle tires.

[0152] 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. The difference lies in the shaping after the extrusion / calendering operation of the mixture. The shape of the rubber mixture thus obtained, not yet vulcanized, for one or more different body mixtures is then used to produce green tires.

[0153] Here, "body mix" basically refers to the rubber mix for the inner components of the tire, such as the squeegee, inner liner (inner layer), core profile, belt, shoulder, belt profile, carcass, bead reinforcement, bead profile, flange profile and bandage.

[0154] The green tire, which has not yet been cured, is then cured.

[0155] For the use of the rubber mixture of the invention in drive belts and other belts, especially conveyor belts, the extruded, not yet vulcanized mixture is given a suitable shape and is often provided, simultaneously or subsequently, with reinforcing elements, such as synthetic fibers or steel cords, usually resulting in a multi-ply structure consisting of one and / or more plies of the rubber mixture, one and / or more plies of the same and / or different reinforcing elements, and one and / or more further plies of the same and / or other rubber mixtures.

[0156] The present 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 of its constituents.

[0157] The vulcanized vehicle tire in at least one component contains a vulcanizate of at least one rubber mixture according to the invention. Those skilled in the art know that most of the substances present, such as rubber, are already present after mixing or may only be present in a chemically modified form after vulcanization.

[0158] In the context of the present invention, "vehicle tires" should be understood to mean pneumatic vehicle tires and solid rubber tires, including industrial tires, as well as tires for construction vehicles, trucks, cars and motorcycles.

[0159] It is preferred if the vehicle tyre according to the invention comprises the rubber mixture according to the invention in at least one external component, whereby the external component is preferably the tread, the sidewall and / or the flange profile.

[0160] The vehicle tyre according to the invention may therefore comprise the rubber mixture according to the invention comprising the inventive compound of formula I), in particular of formula II) and / or III), in several components, optionally in a compatible composition. [Example]

[0161] The present invention will now be more specifically clarified with reference to the following examples.

[0162] Compounds of formula II) as preferred embodiments of compounds of formula I) were prepared as follows.

[0163] The substance 2-phenyl-5-nitro-1H-indole was first synthesized, which is described in EP 1571142 and shown in abbreviated form in the reaction scheme of formula XI): [ka] (In the formula, as is well known, KNO3 represents potassium nitrate and H2SO4 represents sulfuric acid).

[0164] 2-phenyl-5-amino-1H-indole was then synthesized therefrom as shown below: [ka]

[0165] Into a stainless steel autoclave fitted with a Teflon liner, 1.50 g (6.30 mmol, 1 eq.) of 2-phenyl-5-nitro-1H-indole, 0.53 g of palladium on carbon (Pd / C) (5%) (0.4 g for 4.67 mmol of substrate), and 20.0 ml of absolute ethanol were weighed. The reaction mixture was then subjected to hydrogen (H) at 1.5 bar pressure and stirred at room temperature (RT) for 12 hours. Upon completion of the reaction, excess hydrogen was released, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was evaporated to dryness and slurried in a small amount of dichloromethane (DCM). The solid was filtered, washed with a small amount of DCM, and dried under vacuum. A gray to light brown solid was obtained. Yield: 0.75 g (57% of theoretical). 1 H-NMR (Nuclear Magnetic Resonance) (500MHz, DMSO-d6) δ=11.02(s,1H), 7.79(d,J=7.0Hz,2H), 7.42(t,J=7.8Hz,2H), 7.2 6(t,J=7.4Hz,1H), 7.10(d,J=8.5Hz,1H), 6.67(d,J=2.0Hz,1H), 6.62(d,J=2.0Hz,1H), 4.47(s,2H). ESI-MS (electrospray ionization mass spectrometry) [M+H] + =209.

[0166] This compound was then used to synthesize the target compound 2-phenyl-5-(1,3-dimethylbutylamino)-1H-indole (compound of formula II), as shown in formula XIII below: [ka]

[0167] Into a stainless steel autoclave fitted with a Teflon liner, 0.35 g (2.34 mmol, 1 equivalent) of 2-phenyl-5-amino-1H-indole, 0.18 g of palladium on carbon (5%) (0.4 g on a 4.67 mmol substrate), and 20.0 ml of methyl isobutyl ketone (MIBK) were weighed. The reaction mixture was then subjected to hydrogen at 20 bar pressure and stirred at 60 °C for 10 h. Upon completion of the reaction, excess hydrogen was released, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was evaporated to dryness and dried under vacuum. A purity of 98% was achieved. In case of insufficient purity, the material could be purified by crystallization from cyclohexane (preferably) or on silica gel (cyclohexane / EE (ethyl acetate) 10:1). Grayish-purple solid; 0.42 g (85% of theory) is obtained after column chromatography or 0.48 g (98% of theory) without workup. 1 H-NMR(500MHz,DMSO-d6)δ=11.03(s,1H), 7.79(d,J=7.1Hz,2H), 7.42(t,J=7.8Hz,2H), 7.26(t,J=7.4Hz ,1H), 7.13(d,J=8.6Hz,1H), 6.65(d,J=1.3Hz,1H), 6.60(d,J=2.2Hz,1H), 6.54(dd,J=8.7,2.1Hz,1H), 4 .56(d,J=8.9Hz,1H), 3.44(dq,J=8.6,6.4Hz,1H), 1.78(dp,J=13.5,6.7Hz,1H), 1.49(dt,J=13.8,7.0Hz ,1H), 1.22(dt,J=13.5,6.9Hz,1H), 1.10(d,J=6.1Hz,3H), 0.94(d,J=6.7Hz,3H), 0.89(d,J=6.6Hz,3H). 13 C-NMR(126MHz,DMSO-d6)δ=142.6, 137.4, 133.2, 131.1, 130.0, 129.2, 127 .3, 125.0, 113.0, 112.1, 100.9, 98.2, 46.9, 46.7, 25.1, 23.4, 23.1, 21.3. ESI-MS [M+H] + =293. Melting point: 125°C.

[0168] At temperatures above 100°C, in particular above 120°C, in particular between 120°C and 200°C, for example at 120°C, it is in particular likewise the compound of formula III) according to the invention which is formed as the hydrogenation product and which can be separated by column chromatography.

[0169] This is 2-cyclohexyl-5-(1,3-dimethylbutylamino)-1H-indole: [ka] is. 1 H-NMR(500MHz,DMSO-d6)δ=10.33(s,1H), 6.98(d,J=8.4Hz,1H), 6.52(d,J=2.1 Hz,1H), 6.40(dd,J=8.4,2.1Hz,1H), 5.85(s,1H), 4.34(d,J=8.5Hz,1H), 3.43- 3.36(m,1H), 2.67-2.57(m,1H), 2.02-1.95(m,2H), 1.82-1.66(m,4H), 1.49-1. 14(m,7H), 1.06(d,J=6.2Hz,3H), 0.91(d,J=6.6Hz,3H), 0.87(d,J=6.6Hz,3H). 13 C-NMR(126MHz,DMSO-d6)δ=145.38, 142.01, 129.69, 129.45, 111.36, 110.85, 101. 47, 95.68, 47.12, 46.72, 37.33, 33.05, 26.36, 26.23, 25.06, 23.37, 23.06, 21.29. ESI-MS [M+H] + =299.

[0170] Alternatively, it is possible to synthesize the compounds of the invention of formula II) as embodiments of compounds of formula I) directly from 2-phenyl-5-nitro-1H-indole, as shown in formula XIV): [ka]

[0171] Into a stainless steel autoclave fitted with a Teflon liner, 0.50 g (2.01 mmol, 1 equiv.) of 2-phenyl-5-nitro-1H-indole, 0.17 g of platinum on activated carbon (Pt / C) (5%) (0.4 g on a 4.67 mmol substrate), and 20.0 ml of methyl isobutyl ketone were weighed. The reaction mixture was then subjected to hydrogen at 20 bar pressure and stirred at 60 °C for 10 h. Upon completion of the reaction, excess hydrogen was released, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was evaporated to dryness and dried under vacuum. A gray-purple solid was obtained; yield 0.57 g (92% of theoretical). 1 H-NMR(500MHz,DMSO-d6)δ=11.03(s,1H), 7.79(d,J=7.1Hz,2H), 7.42(t,J=7.8Hz,2H), 7.26(t,J=7.4Hz ,1H), 7.13(d,J=8.6Hz,1H), 6.65(d,J=1.3Hz,1H), 6.60(d,J=2.2Hz,1H), 6.54(dd,J=8.7,2.1Hz,1H), 4 .56(d,J=8.9Hz,1H), 3.44(dq,J=8.6,6.4Hz,1H), 1.78(dp,J=13.5,6.7Hz,1H), 1.49(dt,J=13.8,7.0Hz ,1H), 1.22(dt,J=13.5,6.9Hz,1H), 1.10(d,J=6.1Hz,3H), 0.94(d,J=6.7Hz,3H), 0.89(d,J=6.6Hz,3H). 13 C-NMR(126MHz,DMSO-d6)δ=142.6, 137.4, 133.2, 131.1, 130.0, 129.2, 127 .3, 125.0, 113.0, 112.1, 100.9, 98.2, 46.9, 46.7, 25.1, 23.4, 23.1, 21.3. ESI-MS [M+H] + =293.

[0172] The compound of formula III) could be synthesized in a similar manner in high yield according to the above scheme XV). 2-Cyclohexyl-5-nitro-1H-indole was first produced and then reacted in the following manner as summarized in scheme XV-2) to give the compound of formula III) (2-cyclohexyl-5-(1,3-dimethylbutylamino)-1H-indole). [ka]

[0173] Into a stainless steel autoclave fitted with a Teflon liner, 5.75 g (23.54 mmol, 1 equivalent) of 2-cyclohexyl-5-nitro-1H-indole, 2.00 g of platinum on activated carbon (5%) (0.4 g on a 4.67 mmol substrate), and 50.0 ml of methyl isobutyl ketone were weighed. The reaction mixture was then subjected to hydrogen at 20 bar pressure and stirred at 60°C for 10 hours. Upon completion of the reaction, excess hydrogen was released, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was evaporated to dryness and dried under vacuum. It was then crystallized from cyclohexane for purification. A grayish solid was obtained; see above. 1 H-NMR, 13 6.10 g (87% of theory) are obtained with the C-NMR data and the indicated mass.

[0174] Measurement of oxidative induction time (OIT) Compounds of formula II) and III) were investigated under laboratory conditions for their potential protective effect as aging stabilizers by measuring the oxidation induction time.

[0175] For this purpose, the compounds of formulae II) and III) and 6-PPD were in each case mixed with a polymer (liquid synthetic polyisoprene (IR), LIR-50, Kuraray, weight average molecular weight distribution M w = 54000 g / mol, glass transition temperature T g= -63°C) and heated at a constant temperature (180°C) until the onset of oxidation (starting temperature 35°C, heating to 170°C at a heating rate of 20 K / min (Kelvin / min), and then heating to 180°C at a heating rate of 1 K / min; purge gas: nitrogen (N2), volume flow rate 50 ml / min). The specimen was kept isothermal at 180°C for 5 minutes under N2 atmosphere, and then the atmosphere was switched to O2 atmosphere (volume flow rate 50 ml / min).

[0176] DSC (differential scanning calorimetry) was used to determine the oxidation via peaks.

[0177] The time (min) until oxidation was measured.

[0178] The results compared with the known aging stabilizer 6-PPD are summarized in Table 1.

[0179] [Table 1]

[0180] Considering the measurement accuracy of ± (plus / minus) 10 minutes, it is clear that the compound of formula II) is a suitable alternative to the more health-damaging compound 6-PPD. The compound of formula III) achieves even a significantly better protective effect, as the time until the polymer is decomposed by oxygen is extended.

[0181] For use in rubber mixtures for vehicle tyres, the compounds of the invention of formula I), e.g. of formula II) and / or III), are added in one of the mixing stages during the preparation of the rubber mixture in a manner known to those skilled in the art, instead of ageing stabilizers known to those skilled in the art, such as, for example, 6PPD, 7PPD or IPPD.

[0182] Therefore, compounds of formula II) were incorporated into exemplary rubber mixtures according to the invention, as shown in Table 2. The resulting examples of the invention are labeled E1.

[0183] Serving as a comparison is rubber mixture V1, which contains 6PPD instead of the compound of formula II) as ageing stabilizer, the rest of the composition being identical. The amounts in Table 2 are expressed in phr.

[0184] The mixtures were prepared in laboratory mixers with a volume of 300 milliliters to 3 liters under standard conditions in three stages, according to a process customary in the rubber industry. In the first stage (premixing stage), all components except the vulcanization system (sulfur and vulcanization-affecting agents) were mixed for 200 to 600 seconds at 145 to 165°C, with a target temperature of 152 to 157°C. In the second stage, the mixture from the first stage was mixed again. In the third stage (final mixing stage), the vulcanization system was added to obtain the final mixture, which was mixed for 180 to 300 seconds at 90 to 120°C.

[0185] Test specimens were produced from all mixtures by vulcanization under pressure at 160°C–170°C after t95–t100 (measured using a traveling die rheometer according to ASTM D 5289-12 / ISO 6502).

[0186] Also, some specimens of both V1 and E1 were aged (70°C in air for 28 days).

[0187] For all specimens, the following material properties typical for the rubber industry were determined: Resilience at room temperature (RT) according to ISO 4662 or ASTM D 1054 Stress values ​​at 300% elongation (M 300) and breaking elongation at room temperature (RT) according to DIN 53 504 For V1 and E1, the difference between the values ​​of unaged and aged samples was determined.

[0188] The values ​​obtained for V1 were in each case normalized to 100% for reference.

[0189] The values ​​obtained for E1 (difference between unaged and aged) are reported as % performance against this respective V1 criterion, with values ​​above 100% being favorable.

[0190] As can be seen from Table 2, the compounds of the invention of formula II), as representative of the compounds of formula I), provide improved aging stabilization, since important properties such as stress value at 300% elongation (300 modulus), elongation at break and rebound resilience are in each case at higher levels in E1 than in V1 after aging.

[0191] [Table 2] The present application relates to the invention described in the claims, but may also include the following as other aspects. 1. Formula I): [ka] (In the formula, R 1 teeth, xi) an aromatic radical, which may have a substituent selected from the group consisting of a halogen radical, a cyano radical, an ester radical, a ketone radical, an ether radical, and a thioether radical; and xii) linear, branched and cyclic aliphatic C 1 ~C 12 radical, and xiii) aromatic and aliphatic C 1 ~C 12 Radical Combinations selected from the group consisting of: R 2 is a linear, branched, and cyclic, saturated, and unsaturated aliphatic C which may have one or more halogen substituents; 1 ~C 12 radicals, aryl radicals which may have one or more halogen substituents, halogen radicals, preferably fluorine, bromine and chlorine, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radical R 2 are independently the same or different; and R 3 is a linear, branched, and cyclic, saturated, and unsaturated aliphatic C which may have one or more halogen substituents; 1 ~C 12 radicals, aryl radicals which may carry one or more halogen substituents, halogen radicals, of which fluorine, bromine and chlorine are preferred, cyano radicals, ester radicals, ketone radicals, ether radicals and thioether radicals, wherein n takes the value 0 or 1. Compound. 2. n is 1 and R 3 is selected from aliphatic groups and aromatic groups having 1 to 10 carbon atoms. 3. n is 1 and R 3 3. The compound according to 1 or 2 above, wherein is a cyclic saturated or unsaturated aliphatic or cycloaromatic radical having 5 to 10 carbon atoms. 4.R 1 is bonded to the nitrogen atom (N) via a tertiary carbon atom. 5.R 1 5. The compound according to any one of the above items 1 to 4, characterized in that is a branched alkyl radical having 3 to 12 carbon atoms, preferably 3 to 8 carbon atoms. 6.R 1 is selected from 1,3-dimethylbutyl radicals and cyclohexyl radicals; R 1 6. The compound according to any one of the above items 1 to 5, wherein is preferably a 1,3-dimethylbutyl radical. 7. The compound according to any one of the above items 1 to 6, wherein m is 0 (zero). 8.R 3 8. The compound according to any one of the above items 1 to 7, characterized in that is selected from the group consisting of a phenyl radical and a cyclohexyl radical. 9.Formula II):

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Claims

1. Formula I): 【Chemical 1】 (In the formula, R １ teeth, xi) aromatic radicals, and xii) branched and cyclic C 3 -C 12 alkyl radicals; and xiii) combinations of aromatic and C 1 -C 12 alkyl radicals. selected from the group consisting of: R ２ is selected from the group consisting of linear, branched and cyclic, saturated and unsaturated C 1 -C 12 alkyl radicals, and aryl radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radical R ２ are independently the same or different; and R ３ is selected from the group consisting of linear, branched and cyclic, saturated and unsaturated C 1 -C 12 alkyl radicals, and aryl radicals, and n takes the value 0 or 1.

1. A rubber mixture containing a compound of formula (I) above, which comprises at least one diene rubber.

2. n is 1 and R ３ 2. The rubber mixture according to claim 1, characterized in that is selected from alkyl groups having 1 to 10 carbon atoms and aromatic groups.

3. n is 1 and R ３ 3. Rubber mixture according to claim 1 or 2, characterized in that is a cyclic saturated or unsaturated alkyl or cycloaromatic radical having 5 to 10 carbon atoms.

4. R １ 3. Rubber mixture according to claim 1 or 2, characterized in that is linked to the nitrogen atom (N) via a tertiary carbon atom.

5. R １ 3. Rubber mixture according to claim 1, characterized in that is a branched alkyl radical having 3 to 12 carbon atoms.

6. R １ 3. A rubber mixture according to claim 1, wherein is selected from 1,3-dimethylbutyl radicals and cyclohexyl radicals.

7. 3. A rubber mixture according to claim 1, wherein m is 0 (zero).

8. R ３ 3. A rubber mixture according to claim 1, wherein is selected from phenyl and cyclohexyl radicals.

9. The compound of claim 1, wherein the compound has formula II: 【Chemistry 2】 3. A rubber mixture according to claim 1 or 2, characterized in that it has the structure 10. The compound of formula III: 【Chemistry 3】 3. A rubber mixture according to claim 1 or 2, characterized in that it has the structure

11. A rubber mixture as described in claim 1 or 2, comprising at least one diene rubber selected from the group consisting of natural polyisoprene (NR 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.

12. A vehicle tire comprising at least one component of the rubber mixture according to claim 1 or 2.

13. A vehicle tire comprising at least one outer component comprising a rubber mixture according to claim 1 or 2, said outer component being a tread, a sidewall and / or a flange profile.

14. Use of a compound as defined in claim 1 or 2 as an ageing stabilizer or antiozonant in vehicle tires, air springs, bellows, conveyor belts, belts, drive belts, hoses, rubber bands, profiles, seals, membranes, tactile sensors for medical use or robotics, shoe soles or parts thereof, oils, or lubricants.

15. Formula I): 【Chemistry 4】 wherein R 1 is a branched alkyl radical having 3 to 12 carbon atoms; R 2 is selected from the group consisting of linear, branched and cyclic, saturated and unsaturated C 1 -C 12 alkyl radicals, which may have one or more halogen substituents, aryl radicals, which may have one or more halogen substituents, halogen radicals, and cyano radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radicals R 2 are independently of each other identical or different; and R 3 is a cyclic saturated alkyl or cyclic aromatic radical having 5 to 10 carbon atoms, and n takes the value 1. Compound.

16. Formula II): 【Chemistry 5】 16. The compound of claim 15, characterized in that it has the structure:

17. Formula III): 【Chemistry 6】 16. The compound of claim 15, characterized in that it has the structure:

18. 16. Use of a compound according to claim 15 as a dye in fibres or polymers or paper or (decorative) paints or coatings.

19. A process for preparing a compound of formula I) comprising the following process steps: a) providing a compound of formula A) 【Chemistry 7】 b) optionally reacting the compound of formula A) with hydrogen to form a compound of formula B): 【Chemistry 8】 obtaining a compound of c) reacting a compound of formula A) or formula B) with hydrogen or a hydrogenation reagent and a ketone or aldehyde to produce a compound of formula I) 【Chemistry 9】 obtaining a compound of (In the formula, R １ is a branched alkyl radical having 3 to 12 carbon atoms; R ２ is selected from the group consisting of linear, branched and cyclic, saturated and unsaturated C 1 -C 12 alkyl radicals, which may have one or more halogen substituents, aryl radicals, which may have one or more halogen substituents, halogen radicals, and cyano radicals; m takes the value 0 or 1 or 2 or 3, and when m is 2 or 3, the radical R ２ are independently the same or different; and R ３ is a cyclic saturated alkyl or cyclic aromatic radical having 5 to 10 carbon atoms, and n takes the value 1.

20. 20. The process according to claim 19, characterized in that the reaction of hydrogen and said aldehyde or ketone in step c) is carried out using a hydrogenation catalyst at a temperature between 50°C and 70°C, the reaction mixture is subjected to hydrogen at a pressure between 15 and 25 bar, and said reaction is carried out in an autoclave or another pressure reactor.

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