Compound, rubber compound containing the compound, vehicle tire incorporating the rubber compound in at least one component, method for its manufacture, and use of the compound as an anti-aging agent and / or ozone deterrent and / or colorant

Description

[0001] The invention relates to a compound, a rubber mixture containing the compound, a vehicle tire comprising the rubber mixture in at least one component, methods for its production, and the use of the compound as an anti-aging agent and / or ozone stabilizer and / or dye.

[0002] It is known that polymeric materials, such as rubbers in particular, are used in vehicle tires and technical rubber products.

[0003] Natural rubber, synthetic polymers (such as IR, BR, SSBR, ESBR, etc.), as well as natural and synthetic oils, greases, and lubricants are subject to oxidation reactions during prolonged storage and especially in their intended application, which often takes place at higher temperatures. These reactions negatively affect the originally desired properties. Depending on the type of polymer, the polymer chains shorten, sometimes leading to liquefaction of the material, or the material hardens subsequently.

[0004] Anti-aging agents therefore contribute significantly to the longevity of vehicle tires and other technical rubber products. Well-known anti-aging agents include 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).

[0005] These molecules can react with oxygen or ozone or formed radicals, such as alkyl, alkoxy and alkyl peroxy radicals, thus capturing them and protecting the rubbers etc. from further oxidation reactions.

[0006] However, a disadvantage of this class of substances is the suspicion that they could be carcinogenic.

[0007] CN 113 072 741 A and DE 10 2019 212916 A1 each disclose para-phenylenediamines as anti-aging agents in rubber compounds.

[0008] Anti-aging agents that react with and neutralize ozone are also called "ozone protectants" or "anti-ozonants".

[0009] The invention is based on the objective of providing a novel compound that can be used, in particular, as an anti-aging agent in vehicle tires or other technical rubber articles, with a lower hazard potential and sufficient solubility in the respective matrix, for example, and especially in the polymer. This is intended to ensure continued optimal protection against oxygen and ozone while reducing the harmful effects on health and preventing the tendency to bloom.

[0010] The problem is solved by the compound according to claim 1, the rubber compound according to the invention containing the compound, and the vehicle tire according to the invention, which incorporates the rubber compound according to the invention in at least one component. Furthermore, the problem is solved by using the compound as an anti-aging agent and / or an ozone stabilizer.

[0011] The compound according to claim 1 can also be used as a dye. Furthermore, the problem is solved by methods according to the invention for producing the compound according to the invention.

[0012] The compound according to claim 1 has the general formula I): wherein R 1< is selected from the group consisting of benzyl, 1-phenylalkyl groups with a total of 7 to 18 carbon atoms and linear, branched and cyclic aliphatic C 3 to C 12 groups; and wherein R 3< is selected from the group consisting of linear, branched and cyclic aliphatic C 1 to C 12 groups, as well as aryl groups, ether groups and thioether groups, and wherein n takes the value 0 or 1 or 2 or 3 or 4, wherein the groups R 3< are independently the same or different in the case of n equal to 2 or 3 or 4, and wherein R 2< is selected from the group consisting of linear, branched and cyclic aliphatic C 1 to C 12 groups, as well as aryl groups, ether groups and thioether groups; and where m takes the value 0 or 1 or 2 or 3, the remainders R 2< in the case of m equal to 2 or 3 being independently equal or different from each other.

[0013] It is clear to those skilled in the art that in the case of n equal to 0 (zero), 1, 2, or 3, instead of R 3<, an additional hydrogen atom is bonded to the corresponding carbon atom of the saturated ring. Likewise, in the case of m equal to 0, 1, or 2, all other free positions on the benzene ring of the framework are hydrogen atoms.

[0014] It is also clear to those skilled in the art that the representation of the links of (R 2< ) m and (R 3< ) n as well as R 1< HN in the respective (benzene) ring of the framework means that these groups can be arranged at any position on the respective (benzene) ring, except in the case of the benzene ring, not two or more at the same position at the same time, which in the case of the benzene ring would already be excluded due to the tetravalence of the carbon atom.

[0015] Designations such as "C3 to C12 residues" mean, within the scope of the present invention, that residues with 3 to 12 carbon atoms are meant. Separately, "C1" is used to designate the position of the most highly oxidized carbon atom or the highest priority according to the Cahn-Ingold-Prelog (CIP) convention. The meaning is clear to those skilled in the art in the respective context.

[0016] The compound according to the invention is a tetrahydroacridine derivative and, by analogy, it can be expected that it has a lower hazard potential compared to known aging protection agents based on aniline (possible cleavage product of 6-PPD), since, for example, carbazole is classified as carcinogenic, while tetrahydrocarbazole is classified as non-carcinogenic.

[0017] Especially in technical applications such as vehicle tires or other rubber products, a lower hazard potential is a crucial advantage, as abrasion or other degradation processes can release the rubber components.

[0018] The compound according to the invention also exhibits an improved protective effect, especially against polymers, against oxidation and thus aging, compared to 6-PPD.

[0019] The invention encompasses all advantageous embodiments, which are reflected, inter alia, in the claims. In particular, the invention also encompasses embodiments resulting from the combination of different features with varying degrees of preference for these features, such that a combination of a first feature designated as "preferred" or described within an advantageous embodiment with a further feature designated, for example, as "particularly preferred," is also encompassed by the invention.

[0020] Preferably, n is equal to 0 (zero).

[0021] Preferably, m is equal to 0 (zero).

[0022] It is preferred that R< 1< is bonded to the nitrogen atom (N) via a tertiary carbon atom. Thus, the C< 1 atom is preferably a tertiary carbon atom. Within the scope of the present invention, the term "tertiary carbon atom" means a carbon atom bonded to only one hydrogen atom.

[0023] Particularly preferred is R1< a branched alkyl group with 3 to 12 carbon atoms, more preferably 4 to 8 carbon atoms, or a 1-phenylalkyl group with a total of 7 to 10 carbon atoms. Preferably, at least one branch is present at the C1 atom, i.e., at the carbon atom bonded to the nitrogen atom (N), making the C1 atom a tertiary carbon atom.

[0024] R 1< is particularly preferred selected from 1,3-dimethylbutyl, 1-phenylethyl and cyclohexyl residues, and R 1< is again particularly preferred a 1,3-dimethylbutyl residue.

[0025] In a preferred embodiment, the compound has the structure according to Formula II):

[0026] The compound according to formula II) can, particularly in polymers, even further improve protection against oxidation and thus aging. At the same time, the compound according to formula II) is significantly less harmful to health than, for example, 6-PPD or other representatives of this class of substances, as mentioned in the introduction.

[0027] In comparison to 6-PPD, the compound according to Formula II) is therefore a better and at the same time more health- and environmentally friendly anti-aging agent.

[0028] The compound according to the invention according to formula I) or formula II) or all of the above embodiments is particularly suitable as an anti-aging agent and / or ozone protection agent in vehicle tires and / or technical rubber articles, such as in particular an air spring, a bellows, conveyor belt, belt, strap, hose, rubber band, profile, a seal, a membrane, tactile sensors for medical applications or robotic applications, or a shoe sole or parts thereof, and / or oils and / or lubricants.

[0029] A further object of the present invention is therefore the use of the compound according to the invention as an anti-aging agent and / or ozone protection agent in vehicle tires and / or technical rubber articles, such as in particular an air spring, a bellows, a conveyor belt, a belt, a hose, a rubber band, a profile, a seal, a membrane, tactile sensors for medical applications or robotic applications, or a shoe sole or parts thereof, and / or oils and / or lubricants.

[0030] For the use of the compound according to Formula I) or Formula II) or all of the above statements in the aforementioned articles or substances, it is used in a composition and mixed in there.

[0031] In the case of vehicle tires or other technical rubber products, this is particularly a rubber compound.

[0032] Another object of the invention is the use of the compound according to the invention according to formula I) or formula II) or all of the above embodiments as a dye in fibers and / or polymers and / or paper and / or in (coating) paints and varnishes.

[0033] Another aspect of the present invention is a method for producing the compound according to formula I), which comprises the following process steps: a1) Provision of the connection according to formula A1) where the above statements apply to the substituents R 2< , R 3< and the indices m and n, and X is a halogen, in particular fluorine (F), chlorine (Cl) or bromine (Br), ), particularly preferably chlorine or fluorine, most preferably fluorine; b1) reaction of the compound according to formula A1) with a base, in particular potassium carbonate (K 2 CO 3 ), wherein the compound according to formula B1) is obtained: c1) Reaction of the compound according to formula B1) with hydrogen or a hydrogenating reagent, in particular a hydride, and a ketone or aldehyde (R 1< =O), to give the compound according to formula I):

[0034] The base in step b1) is preferably a strong base, such as potassium carbonate (K₂CO₃) or potassium phosphate (K₃PO₄). Potassium carbonate (K₂CO₃) is particularly preferred.

[0035] The reaction according to step b1) is preferably carried out in a polar solvent, such as dimethyl formaldehyde (DMF) or dimethyl sulfoxide (DMSO). Dimethyl formaldehyde (DMF) is particularly preferred.

[0036] Further preferred process features are mentioned together with preferred process features of the further process for producing the compound according to Formula I).

[0037] Another object of the present invention is a further method for producing the compound according to formula I), which comprises at least the following process steps: a2) Provision of a connection according to formula A2): and b2) providing a connection according to formula B2): and c2) reaction of the compound according to formula A2) with the compound according to formula B2) in the presence of a halide carrier, such as PCl 3 , POCl 3 , PBr 3 or SOCl 2 , to give the compound according to formula C2): and d2) reaction of the compound according to formula C2) in the presence of an acid, such as acetic acid in particular, to the compound according to formula B1): and e2) reaction of the compound according to formula B1) with hydrogen or a hydrogenating reagent, in particular a hydride, and a ketone or aldehyde (R 1< =O), to give the compound according to formula I): wherein the above statements apply to the residues R 1< , R 2< , R 3< and the indices m and n and X is a halogen, in particular fluorine (F), chlorine (Cl) or bromine (Br), particularly preferably chlorine or fluorine, most preferably chlorine.

[0038] The halide transferor in step c2) is in particular an acidic halide transferor. The halide transferor in step c2) is preferably selected from the group consisting of PCl3, POCl3, PBr3 and SOCl2. PCl3 or POCl3 is particularly preferred.

[0039] Preferably, the compound according to formula C2) is transferred to a pressure vessel after isolation, preferably without further purification. The conversion according to step d2) to the compound according to formula D2) preferably takes place in a pressure vessel, i.e., in a container suitable for comparatively high pressures, such as in particular an autoclave or another pressure reactor.

[0040] Preferably, the conversion according to step d2) is carried out at a temperature of 200 to 240 °C, in particular and for example 220 °C.

[0041] The acid in step d2) is in particular a water-soluble acid, such as acetic acid, and is used in particular in dilute aqueous solution, such as acetic acid diluted with water. The acid is also in particular a non-nucleophilic acid.

[0042] A "hydrogenation reagent" is a compound that enables hydrogenation. As is known to those skilled in the art, this includes hydrides, especially metal hydrides.

[0043] A suitable hydride is, for example, sodium borohydride.

[0044] Hydrogen is not additionally listed under "hydrogenation reagent" in the context of the present invention, as it is explicitly mentioned as an alternative. Of course, all reagents that generate hydrogen in situ, thereby effecting the hydrogenation, are nevertheless included under "hydrogenation reagent."

[0045] Preferably, the reaction in step c1) or e2) is carried out with hydrogen (H 2 ) and the ketone or aldehyde (R 1< =O), preferably ketone, using a hydrogenation catalyst.

[0046] Preferably, the conversion according to step c1) takes place at a temperature of 120 to 150 °C, in particular for example 140 °C.

[0047] Preferably in step c1) hydrogen is injected at a pressure of 35 to 45 bar, in particular for example 40 bar, and preferably then stirred for 1 to 20 hours, preferably 8 to 13 hours, in particular for example 10 hours.

[0048] Preferably, the conversion according to step e2) takes place at a temperature of 50 to 70 °C, in particular for example 60 °C.

[0049] Preferably in step e2) hydrogen is injected at a pressure of 15 to 25 bar, in particular for example 20 bar, and preferably then stirred for 1 to 20 hours, preferably 8 to 13 hours, in particular for example 10 hours.

[0050] The ketone in step c1) or e2) is the ketone derivative of the subsequent R1< group; in the case of an aldehyde, it is the aldehyde derivative. For the sake of simplicity, the formula R1< = O is used for the aldehyde or ketone, since the R1< group is the part that remains attached to the nitrogen atom after the reaction with the aldehyde or ketone.

[0051] Methyl isobutyl ketone is preferably used in this process.

[0052] Preferably, the reaction with hydrogen in step c1) or e2) takes place in a container suitable for the comparatively high pressures, such as in particular an autoclave or another pressure reactor.

[0053] Preferably, in the process steps in which a reaction with hydrogen takes place, a suitable catalyst, referred to as a "hydrogenation catalyst" within the scope of the present invention, is used.

[0054] Preferably, the hydrogenation catalyst is a noble metal catalyst, such as palladium (Pd) or platinum (Pt). Preferably, the noble metal is used on carbon (C), such as palladium on carbon (Pd / C).

[0055] Furthermore, other well-known catalysts, such as Raney nickel or copper chromite, can also be used.

[0056] The solvent in step c1) or e2) can be either the ketone or aldehyde if it is in liquid form, or an inert solvent such as toluene or xylene, particularly if the ketone or aldehyde is in solid form. In the latter case, the ketone or aldehyde is used as a reactant only in stoichiometric amounts.

[0057] Preferably, a ketone or aldehyde, particularly preferably a ketone, in liquid form is used as the solvent. This eliminates the need for an additional substance such as toluene or xylene.

[0058] The reaction product is, in particular after step c), a mixture of substances comprising the compound according to formula I), wherein purification preferably takes place following step c1) or e2), such as by column chromatography, for example on silica gel.

[0059] Another object of the invention, as described above, is a rubber compound.

[0060] The rubber compound according to the invention contains the compound according to formula I), in particular according to formula II). In principle, the rubber compound according to the invention can be any rubber compound, in particular in which the novel compound according to formula I), in particular according to formula II), acts as an anti-aging agent and / or ozone stabilizer with lower toxicity.

[0061] The rubber compound according to the invention contains at least one rubber.

[0062] Preferably, the rubber mixture according to the invention contains 0.1 to 10 phr, particularly preferably 0.1 to 7 phr, most preferably 1 to 6 phr, of the compound according to formula I), in particular according to formula II).

[0063] The unit phr (parts per hundred parts of rubber by weight) used in this document is the standard unit of measurement for compound formulations in the rubber industry. The dosage of the parts by weight of the individual substances in this document is based on 100 parts by weight of the total mass of all high-molecular-weight rubbers (Mw greater than 20,000 g / mol) present in the mixture.

[0064] According to advantageous embodiments of the invention, the rubber compound according to the invention contains at least one diene rubber. The rubber compound can therefore contain one diene rubber or a mixture of two or more different diene rubbers.

[0065] Diene rubbers are rubbers that are formed by polymerization or copolymerization of dienes and / or cycloalkenes and thus have C=C double bonds either in the main chain or in the side groups.

[0066] The diene rubber is preferably selected from the group consisting of 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, liquid rubbers with a molecular weight Mw greater than 20,000 g / mol, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluorocarbon rubber, silicone rubber, and polysulfide rubber. Epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile butadiene rubber and hydrogenated styrene-butadiene rubber.

[0067] In particular, nitrile rubber, hydrogenated acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber and / or ethylene propylene diene monomer rubber are used in the manufacture of technical rubber articles such as belts, straps and hoses, and / or shoe soles. The preferred application is of the compound compositions known to those skilled in the art for these rubbers – with regard to fillers, plasticizers, vulcanization systems and additives.

[0068] The natural and / or synthetic polyisoprene used in all embodiments can be either cis-1,4-polyisoprene or 3,4-polyisoprene. However, the use of cis-1,4-polyisoprenes with a cis-1,4 content > 90 wt.% is preferred. Such polyisoprene can be obtained by stereospecific polymerization in solution with Ziegler-Natta catalysts or using finely divided lithium alkyls. Alternatively, natural rubber (NR) is such a cis-1,4-polyisoprene in which the cis-1,4 content is greater than 99 wt.%.

[0069] Furthermore, a mixture of one or more natural polyisoprenes with one or more synthetic polyisoprene(s) is also conceivable.

[0070] Within the scope of the present invention, the term "natural rubber" is understood to mean naturally occurring rubber that can be obtained from Hevea rubber trees and "non-Hevea" sources. Non-Hevea sources include, for example, Guayule shrubs and dandelions such as TKS (Taraxacum kok-saghyz; Russian dandelion).

[0071] If the rubber compound according to the invention contains butadiene rubber (= BR, polybutadiene), it can be any type known to those skilled in the art. This includes, among others, the so-called high-cis and low-cis types, whereby polybutadiene with a cis content greater than or equal to 90 wt.% is referred to as a high-cis type and polybutadiene with a cis content less than 90 wt.% as a low-cis type. For example, Li-BR (lithium-catalyzed butadiene rubber) with a cis content of 20 to 50 wt.% is a low-cis polybutadiene. Particularly good properties and low hysteresis of the rubber compound are achieved with a high-cis BR.

[0072] The polybutadiene(s) used can be end-modified and / or functionalized along the polymer chains. These modifications can involve hydroxy groups, ethoxy groups, epoxy groups, siloxane groups, amino groups, aminosiloxane, carboxy groups, phthalocyanine groups, and / or silane sulfide groups. Other modifications, also known as functionalizations, are also possible and are known to those skilled in the art. Such functionalizations can include metal atoms.

[0073] In the event that at least one styrene-butadiene rubber (styrene-butadiene copolymer) is included in the rubber mixture, it can be either solution-polymerized styrene-butadiene rubber (SSBR) or emulsion-polymerized styrene-butadiene rubber (ESBR), and a mixture of at least one SSBR and at least one ESBR can also be used. The terms "styrene-butadiene rubber" and "styrene-butadiene copolymer" are used synonymously within the scope of the present invention.

[0074] The styrene-butadiene copolymer used can be end-group modified and / or functionalized along the polymer chains with the modifications and functionalizations mentioned above for polybutadiene.

[0075] Preferably, the at least one diene rubber is 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.

[0076] According to a particularly preferred embodiment of the 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).

[0077] According to a particularly advantageous embodiment of the invention, the rubber compound contains at least one natural polyisoprene (NR) and / or synthetic polyisoprene (IR), preferably in amounts of 50 to 100 phr, and according to a particularly advantageous embodiment of the invention, 80 to 100 phr, most preferably 95 to 100 phr, and again preferably 100 phr. Such a rubber compound exhibits, in particular, optimized tear and abrasion properties with good processability and reversibility stability.

[0078] In the event that the rubber mixture contains less than 100 phr NR and / or IR, it preferably contains as a 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).

[0079] According to a further particularly advantageous embodiment of the invention, the rubber compound contains at least one natural polyisoprene (NR), preferably in amounts of 5 to 55 phr, and according to a particularly advantageous embodiment of the invention, 5 to 25 phr, most preferably 5 to 20 phr. Such a rubber compound exhibits, in particular, good processability and reversion stability, as well as optimized tear properties and optimal rolling resistance.

[0080] According to a further particularly advantageous embodiment of the invention, the rubber compound contains at least one polybutadiene (BR, butadiene rubber), preferably in amounts of 10 to 80 phr, particularly preferably 10 to 50 phr, and according to a particularly advantageous embodiment of the invention, 15 to 40 phr. This results in particularly good tear and abrasion properties of the rubber compound according to the invention and optimal braking performance.

[0081] According to a further particularly advantageous embodiment of the invention, the rubber compound contains at least one solution-polymerized styrene-butadiene rubber (SSBR), preferably in amounts of 10 to 80 phr, particularly preferably 30 to 80 phr, and according to a particularly advantageous embodiment of the invention, 50 to 70 phr. This results in particularly good rolling resistance properties of the rubber compound according to the invention. According to particularly advantageous embodiments of the invention, SSBR is used in combination with at least one other rubber to achieve an optimal and balanced property profile.

[0082] Preferably, the rubber mixture contains at least one filler, preferably in amounts of 30 to 500 phr, particularly preferably 50 to 400 phr, and again preferably 80 to 300 phr.

[0083] According to advantageous embodiments of the invention, the filler is a reinforcing filler, preferably selected from the group consisting of carbon blacks and silicon dioxide.

[0084] All types of soot known to experts are suitable. The soot is preferably selected from industrial soot and pyrolysis soot, with industrial soot being the preferred choice.

[0085] Preferably, the carbon black has an iodine number, according to ASTM D 1510, also known as iodine adsorption number, between 30 and 250 g / kg, preferably 30 to 180 g / kg, particularly preferably 40 to 180 g / kg, and most preferably 40 to 130 g / kg, and a DBP number according to ASTM D 2414 of 30 to 200 ml / 100 g, preferably 70 to 200 ml / 100 g, particularly preferably 90 to 200 ml / 100 g.

[0086] The DBP number according to ASTM D 2414 determines the specific absorption volume of a carbon black or a light filler using dibutyl phthalate.

[0087] The use of this type of carbon black in the rubber compound, especially for vehicle tires, ensures the best possible compromise between abrasion resistance and heat build-up, which in turn influences the ecologically relevant rolling resistance.

[0088] Particularly suitable and preferred is a carbon black with an iodine adsorption number between 80 and 110 g / kg and a DBP number of 100 to 130 ml / 100g, such as carbon black of type N339.

[0089] The silicon dioxide is preferably amorphous silicon dioxide, for example precipitated silicic acid, which is also referred to as precipitated silicon dioxide. Alternatively, however, pyrogenic silicon dioxide can also be used. However, it is particularly preferred to use finely dispersed, precipitated silica exhibiting 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, particularly preferably 85 to 320 m² / g, and 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, particularly preferably 80 to 300 m² / g, and most preferably 115 to 200 m² / g. Such silicas lead, for example, to particularly good physical properties of the vulcanizates in rubber compounds for tire treads.Furthermore, advantages in mixing processes can arise from a reduction in mixing time while maintaining consistent product properties, leading to improved productivity. Suitable silicas include, for example, those of the Ultrasil®< VN3 type (trade name) from Evonik, as well as highly dispersible silicas, so-called HD silicas (e.g., Zeosil®< 1165 MP from Solvay).

[0090] According to particularly advantageous embodiments of the invention, the rubber mixture contains at least one silica as a filler, preferably in amounts of 30 to 500 phr, particularly preferably 50 to 400 phr, and again preferably 80 to 300 phr.

[0091] In these quantities, silica is present particularly as the sole or main filler (more than 50 wt.% based on the total filler quantity).

[0092] According to further advantageous embodiments of the invention, the rubber mixture contains at least one silica as a further filler, preferably in amounts of 5 to 100 phr, particularly preferably 5 to 80 phr, and again preferably 10 to 60 phr.

[0093] In these quantities, silica is present particularly as an additional filler alongside another main filler, such as carbon black.

[0094] The terms "silica" and "silicic acid" are used synonymously within the scope of the present invention.

[0095] According to particularly advantageous embodiments of the invention, the rubber compound according to the invention contains 0.1 to 60 phr, preferably 3 to 40 phr, particularly preferably 5 to 30 phr, and most preferably 5 to 15 phr, at least one carbon black. In these quantities, carbon black is present, in particular, as a further filler in addition to a main filler, such as, in particular, silica.

[0096] According to further advantageous embodiments of the invention, the rubber compound according to the invention contains 30 to 300 phr, preferably 30 to 200 phr, and particularly preferably 40 to 100 phr of at least one carbon black. In these quantities, carbon black is present as the sole or main filler, optionally in combination with silica in the aforementioned lower quantities.

[0097] According to a particularly advantageous embodiment of the invention, the rubber mixture contains 5 to 60 phr, particularly preferably 5 to 40 phr, at least one carbon black and 50 to 300 phr, preferably 80 to 200 phr, at least one silica.

[0098] The rubber compound may also contain other fillers that have a reinforcing effect or do not.

[0099] Other (non-reinforcing) fillers within the scope of the present invention include aluminosilicates, kaolin, chalk, starch, magnesium oxide, titanium dioxide or rubber gels as well as fibers (such as aramid fibers, glass fibers, carbon fibers, cellulose fibers).

[0100] Other potentially reinforcing fillers include, for example, carbon nanotubes (CNTs) including discrete CNTs, so-called hollow carbon fibers (HCF) and modified CNTs containing one or more functional groups, such as hydroxy, carboxy and carbonyl groups), graphite and graphene and so-called "carbon-silica dual-phase fillers".

[0101] Zinc oxide is not one of the fillers in the present invention.

[0102] Furthermore, the rubber compound may contain common additives in usual proportions by weight, which are preferably added during its manufacture in at least one basic mixing stage. These additives include: a) Antioxidants known in the prior art, such as p-phenylenediamines, like 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... B. Zinc oxide and fatty acids (e.g., stearic acid) and / or other activators, such as zinc complexes like zinc ethylhexanoate, c) activators and / or agents for binding fillers, in particular carbon black or silica, such as S-(3-aminopropyl)thiosulfuric acid and / or its metal salts (binding to carbon black) as well as silane coupling agents (binding to silicon dioxide, in particular silica), d) ozone protection waxes, e) resins, in particular adhesive resins, f) mastication aids, such as2,2'-Dibenzamidodiphenyldisulfide (DBD) and g) Processing aids, in particular fatty acid esters and metal soaps, such as zinc soaps and / or calcium soaps h) Plasticizers, in particular aromatic, naphthenic or paraffinic mineral oil plasticizers, such as MES (mild extraction solvate) or RAE (Residual Aromatic Extract) or TDAE (treated distillate aromatic extract), or rubber-to-liquid (RTL) oils or biomass-to-liquid (BTL) oils, preferably with a polycyclic aromatic content of less than 3 wt% according to method IP 346 or triglycerides, such as e.g. B. Rapeseed oil, or Faktisse or hydrocarbon resins or liquid polymers whose average molecular weight (determined by GPC = gel permeation chromatography, in accordance with BS ISO 11344:2004) is between 500 and 20000 g / mol.

[0103] When using mineral oil, it is preferably selected from the group consisting of DAE (Destilled Aromatic Extracts), RAE (Residual Aromatic Extract), TDAE (Treated Destillated Aromatic Extracts), MES (Mild Extracted Solvents) and naphthenic oils.

[0104] According to particularly advantageous embodiments, the rubber mixture according to the invention contains, in addition to the compound according to formula I), and in particular according to formula II), no anti-aging agents from the group of p-phenylenediamines, in particular those listed a) above. In particular, according to a particularly preferred embodiment, the rubber mixture according to the invention contains 0 to 0.1 phr, in particular 0 phr, of further anti-aging agents based on p-phenylenediamines, which are selected from the group comprising, preferably 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).

[0105] With the preferably very small amounts of 0 to 0.1 phr, or particularly preferably 0 phr, of p-phenylenediamines, and the compound contained according to the invention according to Formula I), and especially according to Formula II), it is possible to achieve improved protection with lower toxicity. Here, the compound according to the invention according to Formula I), and especially according to Formula II), replaces the aforementioned p-phenylenediamines known in the prior art.

[0106] According to further advantageous embodiments of the invention, at least one more of the aforementioned p-phenylenediamine anti-aging agents is included, so that the compound according to the invention only partially replaces the p-phenylenediamines known in the prior art. The advantage of the invention is still achieved, but not to an optimal extent.

[0107] Antiaging agents based on dihydroquinoline, such as TMQ, are included in the rubber compound according to advantageous embodiments, in addition to the compound according to formula I). ​​The amount of dihydroquinoline contained, particularly TMQ, is preferably 0.1 to 3, and more specifically 0.5 to 1.5 phr.

[0108] Ozone protection waxes (group d above) are considered separately and, according to preferred embodiments of the invention, are included in the rubber mixture, regardless of whether additional anti-aging agents a) are included.

[0109] The silane coupling agents can be any type known to the expert.

[0110] Furthermore, one or more different silane coupling agents can be used in combination. The rubber compound can therefore contain a mixture of different silanes.

[0111] The silane coupling agents react with the surface silanol groups of silicon dioxide, especially silicic acid, or other polar groups during the mixing of the rubber or rubber mixture (in situ) or even before the addition of the filler to the rubber as a pretreatment (pre-modification).

[0112] Coupling agents known from the prior art are bifunctional organosilanes that possess at least one alkoxy, cycloalkoxy, or phenoxy group as a leaving group on the silicon atom and that, as a second functionality, exhibit a group which, if necessary after cleavage, can undergo a chemical reaction with the double bonds of the polymer. This latter group can be, for example, the following chemical groups: -SCN, -SH, -NH₂, or -S⁺- (with x = 2 to 8).

[0113] Suitable silane coupling agents include, for example, 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane, or 3,3'-bis(triethoxysilylpropyl)polysulfides with 2 to 8 sulfur atoms, such as 3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT), the corresponding disulfide (TESPD), or mixtures of sulfides with 1 to 8 sulfur atoms and varying concentrations of the different sulfides. TESPT can also be added, for instance, as a mixture with carbon black (trade name X50S® from Evonik).

[0114] Blocked mercaptosilanes, such as those known from WO 99 / 09036, can also be used as silane coupling agents. Silanes as described in WO 2008 / 083241 A1, WO 2008 / 083242 A1, WO 2008 / 083243 A1, and WO 2008 / 083244 A1 can also be used. Suitable silanes include those marketed under the name NXT in various formulations by Momentive, USA, such as 3-octanoylthio-1-propyltriethoxysilane, or those marketed under the name VP Si 363® by Evonik Industries.

[0115] The quantity of other additives in the total quantity is preferably 3 to 150 phr, particularly preferably 3 to 100 phr and most preferably 5 to 80 phr.

[0116] Zinc oxide (ZnO) may be present in the total quantity of other additives in the amounts mentioned above.

[0117] This can include all types of zinc oxide known to experts, such as ZnO granules or powder. Conventionally used zinc oxide typically has a BET surface area of ​​less than 10 m² / g. However, zinc oxide with a BET surface area of ​​10 to 100 m² / g, such as so-called "nano-zinc oxides," can also be used.

[0118] The rubber compound according to the invention is preferably used in vulcanized form, particularly in vehicle tires or other vulcanized technical rubber articles.

[0119] The terms "vulcanized" and "crosslinked" are used synonymously within the scope of the present invention.

[0120] The vulcanization of the rubber compound according to the invention is preferably carried out in the presence of sulfur and / or sulfur donors using vulcanization accelerators, wherein some vulcanization accelerators can also act as sulfur donors. The accelerator is selected from the group consisting of thiazole accelerators, mercapto accelerators, sulfenamide accelerators, thiocarbamate accelerators, thiuram accelerators, thiophosphate accelerators, thiourea accelerators, xanthate accelerators, and guanidine accelerators. The use of a sulfenamide accelerator selected from the group consisting of N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS), benzothiazole-2-sulfene morpholide (MBS), N-tert-butyl-2-benzothiazole sulfenamide (TBBS) and guanidine accelerators such as diphenylguanidine (DPG) is preferred.

[0121] Any sulfur-donating substance known to experts can be used as the sulfur-donating substance.

[0122] Furthermore, vulcanization retarders may be present in the rubber compound.

[0123] The rubber compound is preferably produced according to the standard process in the rubber industry, in which a base mixture containing all components except the vulcanization system (e.g., sulfur and vulcanization-influencing substances) is first produced in one or more mixing stages. The finished mixture is then produced by adding the vulcanization system in a final mixing stage.

[0124] The finished mixture is further processed, for example by extrusion or calendering, and brought into the appropriate shape.

[0125] The rubber compound according to the invention is particularly suitable for use in vehicle tires, especially pneumatic tires. Its application in all tire components is conceivable in principle, particularly in an outer component, especially and preferably in the rim profile, tread, and / or sidewall tread. In the case of a tread with a cap / base construction, the rubber compound according to the invention is preferably used at least in the cap.

[0126] For use in vehicle tires, the mixture is brought into the appropriate shape, preferably of an outer component, as a ready-made mixture before vulcanization and applied during the manufacture of the vehicle tire blank as is known.

[0127] The production of the rubber compound according to the invention for use as a body compound in vehicle tires is carried out as already described. The difference lies in the shaping after the extrusion process or the calendering of the compound. The resulting shapes of the still unvulcanized rubber compound for one or more different body compounds then serve to construct a tire blank.

[0128] The term "body compound" refers to the rubber compounds used for the inner components of a tire, such as essentially the squeegee, inner liner (inner layer), core profile, belt, shoulder, belt profile, carcass, bead reinforcement, bead profile, horn profile and bandage.

[0129] The unvulcanized tire blank is then vulcanized.

[0130] For the use of the rubber compound according to the invention in belts and straps, particularly in conveyor belts, the extruded, still unvulcanized compound is formed into the appropriate shape and is often provided with reinforcing elements, e.g., synthetic fibers or steel cords, either during or after this process. This usually results in a multi-layered structure consisting of one and / or more layers of rubber compound, one and / or more layers of the same and / or different reinforcing elements, and one and / or more further layers of the same and / or a different rubber compound.

[0131] Another object of the present invention is a vehicle tire which contains the rubber compound according to the invention and has the compound according to the invention in at least one component.

[0132] The vulcanized vehicle tire comprises at least one component containing a vulcanizate of at least one rubber compound according to the invention. It is known to those skilled in the art that most substances, such as the rubbers contained therein, are already present, or can be present, in a chemically modified form either after mixing or only after vulcanization.

[0133] Within the scope of the present invention, vehicle tires are understood to mean pneumatic vehicle tires and solid rubber tires, including tires for industrial and construction vehicles, truck, car and two-wheeler tires.

[0134] Preferably, the vehicle tire according to the invention incorporates the rubber compound according to the invention in at least one outer component, wherein the outer component is preferably a tread, a sidewall and / or a horn profile.

[0135] The vehicle tire according to the invention can therefore also have the rubber compound according to the invention containing the compound according to formula I), in particular according to formula II), in several components in a possibly adapted composition.

[0136] The invention will now be explained in more detail using exemplary embodiments.

[0137] The compound according to formula II) as a preferred embodiment of the compound according to formula I) was prepared in the following manner according to a first synthetic route: First, 2-nitroacridin-9(10H)-one was synthesized according to R. Freyer J. Chem. 1963, 4979-5004 - as shown in Scheme YI): where K 2 CO 3 stands for potassium carbonate and DMF for dimethylformamide.

[0138] From this, the synthesis of 7-((4-Methylpentan-2-yl)amino)-1,3,4,10-tetrahydroacridin-9(2H)-one (compound according to formula II) according to scheme YII) was carried out:

[0139] In a stainless steel autoclave lined with a Teflon liner, 0.55 g (2.62 mmol, 1 eq) of 2-nitroacridin-9(10H)-one, 0.224 g of platinum on carbon (5%) (0.4 g on 4.67 mmol substrate), and 20.0 mL of methyl isobutyl ketone were weighed out. Hydrogen pressure of 40 bar was applied, and the mixture was stirred at 140°C for 10 hours. After completion of the reaction, excess hydrogen was purged, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was concentrated to dryness and dried under vacuum. The residue was analyzed by LC-MS. The results are shown in Table 1. Table 1 substance Yield [%] Retention time [min] 45 3.86 44 3.56 10 2.6

[0140] The substance can be purified by column chromatography on silica gel (cyclohexane / ethyl acetate 10:1 → 1:1). Pale yellow solid; yield 0.34 g (40% of theory). Analysis of 7-((4-Methylpentan-2-yl)amino)-1,3,4,10-tetrahydroacridin-9(2H)-one:

[0141] 1< H-NMR ( English "nuclear magnetic resonance") (500 MHz, DMSO- d 6 ) δ = 11.02 (s, 1H), 7.23 (d, J = 8.9 Hz, 1H), 7.04 (d, J = 2.7 Hz, 1H), 6.97 (dd, J = 8.9, 2.7 Hz, 1H), 5.35 (d, J = 8.4 Hz, 1H), 3.54 - 3.41 (m, 1H), 2.65 (t, J = 6.2 Hz, 2H), 2.42 (t, J = 6.2 Hz, 2H), 1.85 - 1.60 (m, 5H), 1.48 (dt, J = 13.9, 7.1 Hz, 1H), 1.24 (ddd, J = 13.6, 8.6, 5.8 Hz, 1H), 1.10 (d, J = 6.2 Hz, 3H), 0.93 (d, J = 6.6 Hz, 3H), 0.87 (d, J = 6.6 Hz, 3H).

[0142] 13< C-NMR (126 MHz, DMSO) δ = 175.7, 145.0, 144.3, 131.6, 125.2, 121.0, 118.7, 114.0, 102.3, 46.2, 46.2, 27.5, 26.8, 25.0, 23.2, 23.0, 22.7, 22.4, 22.2, 20.9.

[0143] ESI-MS (Elektrosprayionisation Massenspektrometrie) [M+H] +< = 299.

[0144] The compound according to formula II) was also synthesized - as shown in schemes XI) and XII) - according to another synthesis route:

[0145] The synthesis steps according to Scheme XI) followed the literature, see Cross, R. Matthew et al.; Journal of Medicinal Chemistry (2011), 54(13), 4399-4426.

[0146] The synthesis steps according to Scheme XII) (synthesis of 7-((4-methylpentan-2-yl)amino)-1,3,4,10-tetrahydroacridin-9(2H)-one, molecule according to formula II) were carried out as follows: 0.24 g (0.98 mmol, 1 eq) of 6-nitro-1,3,4,10-tetrahydroacridin-9(2H)-one, 0.082 g of platinum on carbon (5%) (0.4 g on 4.67 mmol substrate), and 20.0 mL of methyl isobutyl ketone (MIBK) were weighed into a stainless steel autoclave lined with a Teflon liner. Hydrogen pressure of 20 bar was then applied, and the mixture was stirred at 60°C for 10 hours. After completion of the reaction, the excess hydrogen was purged, and the suspension was filtered through Celite® and washed with ethanol. The filtrate was concentrated to dryness and dried under vacuum; yield 98%; for analysis see above. Measurement of the oxidation-induction time (OIT, English "oxidation induction time")

[0147] The compound according to formula II) was investigated for its potential protective effect as an anti-aging agent by measuring the oxidation-induction time under laboratory conditions. For this purpose, the compounds according to formula II) and 6-PPD were each heated together with a polymer (liquid synthetic polyisoprene (IR), LIR-50, Kuraray, weight mean of the molecular weight distribution Mw = 54,000 g / mol, glass transition temperature Tg = -63°C) at a constant temperature (180°C) until oxidation occurred (starting temperature 35°C, heating to 170°C at a rate of 20 K / min (Kelvin per minute), heating to 180°C at a rate of 1 K / min; purge gas: nitrogen (N2) at a flow rate of 50 mL / min).

[0148] The sample was held isothermally at 180°C for 5 minutes under an N2 atmosphere and then switched to an O2 atmosphere (with a volume flow of 50 mL / min).

[0149] Oxidation was measured via a peak using DSC (dynamic differential scanning calorimetry; English "differential scanning calorimetry") determined.

[0150] The time until oxidation was measured in minutes.

[0151] The results are summarized in Table 2 in comparison to the well-known antioxidant 6-PPD. Table 2 substance Time [min] 6-PPD 116±10 212±10

[0152] Taking into account the measurement accuracy of ± (plus or minus) 10 minutes, it becomes apparent that the compound according to Formula II) achieves a significantly better protective effect, as it takes longer for the polymer to decompose and thus oxidize due to oxygen. Therefore, the compound according to Formula I) or Formula II) is more environmentally and health-friendly than 6-PPD or other representatives of the substance class, as explained above, and is also a better anti-aging agent.

Claims

1. Compound of formula I): wherein R1 is selected from the group consisting of benzyl radicals, 1-phenylalkyl radicals having altogether 7 to 18 carbon atoms and linear, branched and cyclic aliphatic C3- to C12-radicals; and wherein R3 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals, and wherein n assumes the value 0 or 1 or 2 or 3 or 4, wherein when n is 2 or 3 or 4 the radicals R3 are independently of one another identical or different, and wherein R2 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals; and wherein m assumes the value 0 or 1 or 2 or 3, wherein when m is 2 or 3 the radicals R2 are independently of one another identical or different.

2. Compound according to Claim 1, characterized in that n is 0 (zero).

3. Compound according to Claim 1 or 2, characterized in that m is 0 (zero).

4. Compound according to any of the preceding claims, characterized in that R1 is bonded to the nitrogen atom (N) via a tertiary carbon atom.

5. Compound according to any of the preceding claims, characterized in that R1 is a branched alkyl radical having 3 to 12 carbon atoms, preferably 4 to 8 carbon atoms, or a 1-phenylalkyl radical having altogether 7 to 10 carbon atoms.

6. Compound according to any of the preceding claims, characterized in that R1 is selected from the group consisting of 1,3-dimethylbutyl, 1-phenylethyl and cyclohexyl radicals, wherein R1 is preferably a 1,3-dimethylbutyl radical.

7. Compound according to any of the preceding claims, characterized in that it has the structure of formula II):

8. Use of the compound according to any of Claims 1 to 7 as an aging stabilizer, in particular in vehicle tyres or technical rubber articles, such as in particular an air spring, bellows, conveyor belt, belt, drive belt, hose, rubber band, profile, a seal, a membrane, tactile sensors for medical applications or robotics applications, or a shoe sole or parts thereof, and / or oils and / or lubricants.

9. Use of the compound according to any of Claims 1 to 7 as a dye in fibres and / or polymers and / or paper and / or in (decorating) paints and coatings.

10. Process for producing the compound of formula I) which comprises the following process steps: a1) providing the compound of formula A1) b1) reacting the compound of formula A1) with a base, in particular potassium carbonate (K2CO3), to obtain the compound of formula B1): c1) reacting the compound of formula B1) with hydrogen or a hydrogenating reagent, and a ketone or aldehyde, to afford the compound of formula I): wherein R1 is selected from the group consisting of benzyl radicals, 1-phenylalkyl radicals having altogether 7 to 18 carbon atoms and linear, branched and cyclic aliphatic C3- to C12-radicals; and wherein R3 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals, and wherein n assumes the value 0 or 1 or 2 or 3 or 4, wherein when n is 2 or 3 or 4 the radicals R3 are independently of one another identical or different, and wherein R2 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals; and wherein m assumes the value 0 or 1 or 2 or 3, wherein when m is 2 or 3 the radicals R2 are independently of one another identical or different, and wherein X is a halogen, in particular fluorine (F), chlorine (CI) or bromine (Br).

11. Process according to Claim 10, characterized in that the reaction in step c1) with hydrogen and the aldehyde or ketone, preferably ketone, is carried out using a hydrogenation catalyst and at a temperature of 120°C to 150°C and the reaction mixture is subjected to hydrogen at a pressure of 35 to 45 bar and the reaction is carried out in an autoclave or in another pressure reactor.

12. Process for producing the compound of formula I) which comprises the following process steps: a2) providing a compound of formula A2): and b2) providing a compound of formula B2): and c2) reacting the compound of formula A2) with the compound of formula B2) in the presence of a halogenating agent such as PCl3, POCl3, PBr3 or SOCl2 to afford the compound of formula C2): and d2) reacting the compound of formula C2) in the presence of an acid, such as in particular acetic acid, to afford the compound of formula B1): and e2) reacting the compound of formula B1) with hydrogen or a hydrogenating reagent, and a ketone or aldehyde, to afford the compound of formula I): wherein R1 is selected from the group consisting of benzyl radicals, 1-phenylalkyl radicals having altogether 7 to 18 carbon atoms and linear, branched and cyclic aliphatic C3- to C12-radicals; and wherein R3 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals, and wherein n assumes the value 0 or 1 or 2 or 3 or 4, wherein when n is 2 or 3 or 4 the radicals R3 are independently of one another identical or different, and wherein R2 is selected from the group consisting of linear, branched and cyclic aliphatic C1- to C12-radicals, and aryl radicals, ether radicals and thioether radicals; and wherein m assumes the value 0 or 1 or 2 or 3, wherein when m is 2 or 3 the radicals R2 are independently of one another identical or different, and wherein X is a halogen, in particular fluorine (F), chlorine (CI) or bromine (Br).

13. Process according to Claim 12, characterized in that the reaction in step e2) with hydrogen and the aldehyde or ketone, preferably ketone, is carried out using a hydrogenation catalyst and at a temperature of 50°C to 70°C and the reaction mixture is subjected to hydrogen at a pressure of 15 to 25 bar and the reaction is carried out in an autoclave or in another pressure reactor.

14. Rubber mixture containing the compound according to any of Claims 1 to 7, wherein the rubber mixture preferably contains at least one diene rubber which is particularly preferably 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.

15. Vehicle tyre comprising the rubber mixture according to Claim 14 in at least one component, preferably in at least one outer component, wherein the outer component is preferably a tread, a sidewall and / or a flange profile.