DE102021213723A1 - Connection, rubber mixture containing the connection, vehicle tire which has the rubber mixture in at least one component, method for producing the connection and use of the connection as anti-aging agent and/or antioxidant and/or colorant - Google Patents

Abstract

The invention relates to a compound, a rubber compound containing the compound, a vehicle tire which has the rubber compound in at least one component, a method for producing the compound and the use of the compound as an anti-aging agent and/or antioxidant and/or dye. The compound according to the invention has the following formula I):

Description

The invention relates to a compound, a rubber compound containing the compound, a vehicle tire which has the rubber compound in at least one component, a method for producing the compound and the use of the compound as an aging inhibitor and/or antioxidant and/or colorant.

It is known that polymeric materials, such as rubbers in particular, are used in vehicle tires and technical rubber articles. Natural rubber, synthetic polymers (such as IR, BR, SSBR, ESBR, etc.) but also natural and synthetic oils, greases and lubricants are subject to oxidation reactions when stored for a long period of time and especially in the target application, which often takes place at higher temperatures, which can have adverse effects affect the original desired properties. Depending on the type of polymer, the polymer chains are shortened to the point of liquefying the material or the material is subsequently hardened.

Anti-aging agents therefore make a significant contribution to the longevity of vehicle tires and other technical rubber items. Known antioxidants are aromatic amines, such as 6PPD (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine), IPPD (N-isopropyl-N'-phenyl-p-phenylenediamine) or SPPD (N- (1-phenylethyl)-N'-phenyl-p-phenylenediamine). These molecules can react with oxygen or ozone or radicals formed, such as alkyl, alkoxy and alkylperoxy radicals, and thus intercept them and thus protect the rubber, etc. from further oxidation reactions.

The disadvantage of this class of substances, however, is the suspicion that they could be carcinogenic.

Anti-aging agents that react with ozone in particular and intercept it are also referred to as “ozone protection agents” or “antiozonants”.

The object of the invention is to provide 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 risk potential and sufficient solubility in the respective matrix, for example and in particular in the polymer. This is intended to ensure continued optimal or even improved protection against oxygen and ozone while reducing the health hazard and to prevent the tendency to bloom.

The object is achieved by the compound according to the invention as claimed in claim 1, the rubber mixture according to the invention containing the compound and the vehicle tire according to the invention which has the rubber mixture according to the invention in at least one component. Furthermore, the object is achieved by the method for producing the compound and the use of the compound as an aging inhibitor and/or antioxidant and/or antiozonant.
The compound according to claim 1 can further be used as a dye.

The compound according to claim 1 has the formula I):

The compound according to formula I) is therefore N-(4-methylpentan-2-yl)-9,10-dihydroacridin-2-amine.

The compound of the formula I) has an increased reactivity towards oxygen, ozone or radicals compared to the known anti-aging agents, such as in particular 6PPD, which means that the compound of the formula I) has an improved protective effect, in particular in vehicle tires and other technical rubber articles, but also in oils and lubricants.

The compound according to formula I) is also an acridine derivative and as such is less toxic than known diamine antioxidants such as 6PPD or IPPD.

In rubber mixtures, the compound according to the invention exhibits an improved anti-aging effect compared to 6PPD and is therefore suitable as a replacement for 6PPD, the degradation products of which are extremely toxic for coho salmon and therefore probably also for other aquatic organisms.
In addition, the compound according to the invention surprisingly has very good solubility in rubber mixtures, in particular for vehicle tires and other technical rubber articles, which could be attributed to the 1,3-dimethylbutyl group on the nitrogen atom.

In principle, however, the invention should not be bound to a specific mechanism of action or a specific explanation.

All advantageous configurations, which are reflected in the patent claims, among other things, are included in the invention. In particular, the invention also includes configurations that result from the combination of different features of different gradations when these features are preferred, so that a combination of a first feature referred to as “preferred” or a feature described in the context of an advantageous embodiment with a further feature, e.g. B. "particularly preferred" designated feature is covered by the invention.

The compound of the formula I) according to the invention is particularly useful as an anti-aging agent and/or anti-ozone agent in vehicle tires and/or other technical rubber articles, such as in particular an air spring, a bellows, a conveyor belt, a belt, a belt, a hose, a rubber band, a profile, a seal, a membrane, tactile sensors for medical applications or robot applications, or a shoe sole or parts thereof, and/or oils and/or lubricants.

The compound of the formula I) according to the invention is particularly suitable for producing a rubber article, in particular an air spring, a bellows, conveyor belt, belt, belt, hose, rubber band, profile, a seal, a membrane, tactile sensors for medical applications or robotic applications, or a shoe sole or parts thereof.

To use the compound according to formula I) in the articles or substances mentioned, it is used in a composition and mixed into it.
In the case of vehicle tires or other technical rubber articles, this is in particular a rubber mixture.

A further object of the invention is the use of the compound according to the invention of the formula I) in oils, lubricants, such as in particular fuels or fuels for engines. In particular, the connection according to the invention can thus be used in engines.

Another object of the invention is the use of the compound according to the invention of the formula I) as a dye in fibers and/or polymers and/or paper and/or in (coating) paints and lacquers.

A further object of the invention, as stated above, is a rubber mixture.

The rubber mixture according to the invention contains the compound of the formula I). The rubber mixture according to the invention can in principle be any rubber mixture, in particular in which the new compound according to the invention of the formula I) acts as an anti-aging agent and/or an anti-ozone agent with lower toxicity.

The rubber mixture according to the invention contains at least one rubber.

The rubber mixture according to the invention preferably contains 0.1 to 10 phr, particularly preferably 0.1 to 7 phr, very particularly preferably 1 to 6 phr, of the compound of the formula I).

The specification phr (parts per hundred parts of rubber by weight) used in this document is the quantity specification for compound formulations customary in the rubber industry. In this document, the dosage of the parts by weight of the individual substances is based on 100 parts by weight of the total mass of all high molecular weight ( _Mw greater than 20,000 g/mol) rubbers present in the mixture.

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

Diene rubbers are rubbers which 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.

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 M _w greater than 20000 g/mol, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluorine rubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile-butadiene rubber and hydrogenated styrene-butadiene rubber.

In particular, nitrile rubber, hydrogenated acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber and/or ethylene-propylene-diene rubber are used in the production of technical rubber articles, such as belts, belts and hoses, and/or shoe soles. The mixture compositions known to those skilled in the art for these rubbers, which are particular with regard to fillers, plasticizers, vulcanization systems and additives, are preferably used.

The natural and/or synthetic polyisoprene of all embodiments can be both cis-1,4-polyisoprene and 3,4-polyisoprene. However, the use of cis-1,4-polyisoprenes with a cis-1,4 content of >90% by weight is preferred. On the one hand, such a polyisoprene can be obtained by stereospecific polymerization in solution with Ziegler-Natta catalysts or using finely divided lithium alkyls. On the other hand, natural rubber (NR) is a cis-1,4 polyisoprene in which the cis-1,4 fraction in the natural rubber is greater than 99% by weight.
A mixture of one or more natural polyisoprenes with one or more synthetic polyisoprene(s) is also conceivable.

As used herein, the term "natural rubber" means naturally occurring rubber that can be obtained from Hevea rubber trees and "non-Hevea" sources. Non-Hevea sources include guayule shrubs and dandelions such as TKS (Taraxacum kok-saghyz; Russian dandelion).

If butadiene rubber (=BR, polybutadiene) is contained in the rubber mixture according to the invention, it can be of any type known to the person skilled in the art. These include the so-called high-cis and low-cis types, polybutadiene with a cis content greater than or equal to 90% by weight being the high-cis type and polybutadiene with a cis content of less than 90% by weight. % is called the low-cis type. An example of a low cis polybutadiene is Li-BR (lithium catalyzed butadiene rubber) having a cis content of 20 to 50% by weight. Particularly good properties and low hysteresis of the rubber compound are achieved with a high-cis BR.

The polybutadiene(s) used can/can be end-group-modified with modifications and functionalizations and/or functionalized along the polymer chains. The modification can be those with hydroxy groups and/or ethoxy groups and/or epoxy groups and/or siloxane groups and/or amino groups and/or aminosiloxane and/or carboxy groups and/or phthalocyanine Act groups and / or silane sulfide groups. However, other modifications known to those skilled in the art, also referred to as functionalizations, are also possible. Metal atoms can be part of such functionalizations.

If at least one styrene-butadiene rubber (styrene-butadiene copolymer) is contained in the rubber mixture, it can be both solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR ) act, in which case 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 in the context of the present invention.
The styrene-butadiene copolymer used can be modified with the modifications mentioned above for polybutadiene gene and functionalization end groups and / or functionalized along the polymer chains.

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.

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).

According to a particularly advantageous embodiment of the invention, the rubber mixture contains at least one natural polyisoprene (NR), preferably in amounts of 50 to 100 phr, and according to a particularly advantageous embodiment of the invention 80 to 100 phr, very particularly preferably 95 to 100 phr, in turn preferably 100 phr. A rubber mixture of this type shows in particular optimized tear properties and abrasion properties with good processability and reversion stability.
If the rubber mixture contains less than 100 phr NR, it preferably contains at least one diene rubber as an additional rubber, which is selected from the group consisting of synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR) and emulsion polymerized styrene butadiene rubber (ESBR).

According to a further particularly advantageous embodiment of the invention, the rubber mixture 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, very particularly preferably 5 to 20 phr. A rubber mixture of this type shows, in particular, good processability and reversion stability, as well as optimized tear properties and optimum rolling resistance behavior.

According to a further particularly advantageous embodiment of the invention, the rubber mixture 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. In this way, particularly good tear and abrasion properties of the rubber mixture according to the invention and optimal braking behavior are achieved.

According to a further particularly advantageous embodiment of the invention, the rubber mixture 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 achieves particularly good rolling resistance properties for the rubber mixture according to the invention. According to particularly advantageous embodiments of the invention, SSBR is used in combination with at least one other rubber in order to achieve an optimal and balanced property profile.

The rubber mixture preferably contains at least one filler, preferably in amounts of 30 to 500 phr, particularly preferably 50 to 400 phr, again preferably 80 to 300 phr.
According to advantageous embodiments of the invention, the filler is a reinforcing filler, preferably selected from the group consisting of carbon blacks and silica.

Suitable carbon blacks are all types of carbon black known to those skilled in the art. The carbon black is preferably selected from carbon blacks and pyrolysis carbon blacks, carbon blacks being more preferred.

The carbon black preferably has an iodine number, according to ASTM D 1510, which is also referred to as the iodine adsorption number, between 30 and 250 g/kg, preferably 30 to 180 g/kg, particularly preferably 40 to 180 g/kg, and very particularly 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. The DBP number according to ASTM D 2414 determines the specific absorption volume of a carbon black or a light-colored filler using dibutyl phthalate.

The use of such a 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.
Particularly suitable and preferred is a carbon black with an iodine adsorption number of between 80 and 110 g/kg and a DBP number of 100 to 130 ml/100 g, such as in particular carbon black of the N339 type.

The silica is preferably amorphous silica, for example precipitated silicic acid, also referred to as precipitated silica. Alternatively, for example, pyrogenic silicon dioxide can also be used. However, it is particularly preferred if a finely divided, precipitated silica is used which has a nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132) from 35 to 400 m ² /g, preferably from 35 to 350 m ² / g, more preferably from 85 to 320 m ² / g and most preferably from 120 to 235 m ² / g, and a CTAB surface area (according to ASTM D 3765) from 30 to 400 m ² / g, preferably from 30 to 330 m ² /g, more preferably from 80 to 300 m ² /g and most preferably from 115 to 200 m ² /g. Such silicas lead z. B. in rubber mixtures for tire treads to particularly good physical properties of the vulcanizates. In addition, there can be advantages in compound processing by reducing the mixing time with the same product properties, which lead to improved productivity. As silicas z. B. both those of the type Ultrasil® VN3 (trade name) from Evonik and highly dispersible silicas, so-called HD silicas (e.g. Zeosil® 1165 MP from Solvay), can be used.

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, again preferably 80 to 300 phr.
In these amounts, silicic acid is present in particular as the sole or main filler (more than 50% by weight, based on the total amount of filler).

According to further advantageous embodiments of the invention, the rubber mixture contains at least one silica as an additional filler, preferably in amounts of 5 to 100 phr, particularly preferably 5 to 80 phr, again preferably 10 to 60 phr.
Silicic acid is contained in these amounts in particular as a further filler in addition to another main filler, such as in particular a carbon black.

The terms “silicic acid” and “silica” are used synonymously in the context of the present invention.

According to particularly advantageous embodiments of the invention, the rubber mixture according to the invention contains from 0.1 to 60 phr, preferably from 3 to 40 phr, particularly preferably from 5 to 30 phr, very particularly preferably from 5 to 15 phr, of at least one carbon black. In these amounts, carbon black is contained in particular as a further filler in addition to a main filler, such as in particular silica.

According to further advantageous embodiments of the invention, the rubber mixture according to the invention contains 30 to 300 phr, preferably 30 to 200 phr, particularly preferably 40 to 100 phr of at least one carbon black. In these amounts, carbon black is present as the only filler or as the main filler and optionally in combination with silica in the smaller amounts mentioned above.

According to 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.

The rubber mixture can also contain other fillers which have a reinforcing effect or which do not have a reinforcing effect.

Within the scope of the present invention, the other (non-reinforcing) fillers include aluminosilicates, kaolin, chalk, starch, magnesium oxide, titanium dioxide or rubber gels and fibers (such as, for example, aramid fibers, glass fibers, carbon fibers, cellulose fibers).

Other possible reinforcing fillers are, for example, carbon nanotubes (CNT) including discrete CNTs, so-called hollow carbon fibers (HCF) and modified CNT containing one or more functional groups such as hydroxyl, carboxy and carbonyl groups), graphite and graphene and so-called “carbon-silica dual-phase filler”.

In the context of the present invention, zinc oxide does not belong to the fillers.

1. a) im Stand der Technik bekannte Alterungsschutzmittel, wie z. B. p-Phenylendiamine, wie N-Phenyl-N'-(1,3-dimethylbutyl)-p-phenylendiamin (6PPD), N,N'-Diphenyl-p-phenylendiamin (DPPD), N-(1-phenylethyl)-N'-phenyl-p-phenylendiamin (SPPD), N,N'-Ditolyl-p-phenylendiamin (DTPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylendiamin (7PPD), N-Isopropyl-N'-phenyl-p-phenylendiamin (IPPD), oder Dihydrochinoline, wie 2,2,4-Trimethyl-1,2-dihydrochinolin (TMQ),
2. b) Aktivatoren, wie z. B. Zinkoxid und Fettsäuren (z. B. Stearinsäure) und/oder sonstige Aktivatoren, wie Zinkkomplexe wie z.B. Zinkethylhexanoat,
3. c) Aktivatoren und/oder Agenzien für die Anbindung von Füllstoffen, insbesondere Ruß oder Kieselsäure, wie beispielsweise S-(3-Aminopropyl)Thioschwefelsäure und/oder deren Metallsalze (Anbindung an Ruß) sowie Silan-Kupplungsagenzien (Anbindung an Siliciumdioxid, insbesondere Kieselsäure),
4. d) Ozonschutzwachse,
5. e) Harze, insbesondere Klebharze,
6. f) Mastikationshilfsmittel, wie z. B. 2,2'-Dibenzamidodiphenyldisulfid (DBD) und
7. g) Prozesshilfsmittel, wie insbesondere Fettsäureester und Metallseifen, wie z.B. Zinkseifen und/oder Calciumseifen
8. h) Weichmacher, wie insbesondere wie aromatische, naphthenische oder paraffinische Mineralölweichmacher, wie z.B. MES (mild extraction solvate) oder RAE (Residual Aromatic Extract) oder TDAE (treated distillate aromatic extract), oder Rubber-to-Liquid-Öle (RTL) oder Biomass-to-Liquid-Öle (BTL) bevorzugt mit einem Gehalt an polycyclischen Aromaten von weniger als 3 Gew.-% gemäß Methode IP 346 oder Triglyceride, wie z. B. Rapsöl, oder Faktisse oder Kohlenwasserstoffharze oder Flüssig-Polymere, deren mittleres Molekulargewicht (Bestimmung per GPC = gel permeation chromatography, in Anlehnung an BS ISO 11344:2004) zwischen 500 und 20000 g/mol liegt.

Furthermore, the rubber mixture can contain customary additives in customary parts by weight, which are preferably added in at least one basic mixing stage during its production. These additives include

1. a) anti-aging agents known in the prior art, e.g. B. 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),
2. b) activators, such as e.g. B. zinc oxide and fatty acids (z. B. stearic acid) and / or other activators such as zinc complexes such as zinc ethylhexanoate,
3. c) Activators and/or agents for binding fillers, in particular carbon black or silicic acid, such as S-(3-aminopropyl)thiosulfuric acid and/or its metal salts (binding to carbon black) and silane coupling agents (binding to silicon dioxide, in particular silicic acid) ,
4. d) antiozonant waxes,
5. e) resins, in particular adhesive resins,
6. f) mastication aids, such as e.g. B. 2,2'-dibenzamidodiphenyl disulfide (DBD) and
7. g) processing aids, such as in particular fatty acid esters and metal soaps, such as zinc soaps and/or calcium soaps
8. h) plasticizers, such as 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 oils (RTL) or Biomass-to-Liquid oils (BTL) preferably with a content of polycyclic aromatics of less than 3% by weight according to method IP 346 or triglycerides, such as. B. rapeseed oil, or facts or hydrocarbon resins or liquid polymers whose average molecular weight (determined by GPC = gel permeation chromatography, based on BS ISO 11344:2004) is between 500 and 20,000 g/mol.

When using mineral oil, this is preferably selected from the group consisting of DAE (Distillated Aromatic Extracts), RAE (Residual Aromatic Extract), TDAE (Treated Distillated Aromatic Extracts), MES (Mild Extracted Solvents) and naphthenic oils.

According to particularly advantageous embodiments, in addition to the compound according to the invention of the formula I), the rubber mixture according to the invention does not contain any aging inhibitors from the group of p-phenylenediamines, in particular those from list a) above. In particular, according to a particularly preferred embodiment, the rubber mixture according to the invention contains from 0 to 0.1 phr, in particular 0 phr, of further aging inhibitors based on p-phenylenediamines, which are selected from the group containing, 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) .

With the preferably very small amounts of 0 to 0.1 phr or particularly preferably 0 phr of the p-phenylenediamines mentioned and the compound of the formula I) contained according to the invention, it is possible to achieve a comparable protective effect with lower toxicity. Here, the compound according to the invention of the formula I) replaces the p-phenylenediamines mentioned which are known in the prior art.

According to further advantageous embodiments of the invention, at least one other of the p-phenylenediamine anti-aging agents mentioned is also present, so that the compound according to the invention only partially replaces the p-phenylenediamines known in the prior art. This also achieves the advantage according to the invention, just not to the optimum extent.

According to advantageous embodiments, aging inhibitors based on dihydroquinoline, such as TMQ, are present in the rubber mixture in addition to the compound according to the invention of the formula I). The amount of dihydroquinolines present, such as TMQ in particular, is preferably from 0.1 to 3, in particular from 0.5 to 1.5 phr.

Anti-ozone waxes (group d above) are considered separately and, according to preferred embodiments of the invention, are present in the rubber mixture, regardless of whether additional anti-aging agents a) are present.

The silane coupling agents can be of any type known to those skilled in the art.

Furthermore, one or more different silane coupling agents can be used in combination. The rubber mixture can thus contain a mixture of different silanes.

The silane coupling agents react with the surface silanol groups of the silicon dioxide, in particular the silicic acid, or other polar groups during the mixing of the rubber or the rubber mixture (in situ) or even before the filler is added to the rubber in the sense of a pretreatment (premodification).

Coupling agents known from the prior art are bifunctional organosilanes which have at least one alkoxy, cycloalkoxy or phenoxy group as a leaving group on the silicon atom and which have a group as another functionality which, after cleavage, can undergo a chemical reaction with the double bonds of the polymer. The latter group can be z. B. be the following chemical groups: -SCN, -SH, -NH ₂ or -S _x - (where x = 2 to 8).

Thus, as silane coupling agents z. B. 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane or 3,3'-bis (triethoxysilylpropyl) polysulfides having 2 to 8 sulfur atoms, such as. B. 3,3'-bis (triethoxysilylpropyl) tetrasulfide (TESPT), the corresponding disulfide (TESPD) or mixtures of the sulfides with 1 to 8 sulfur atoms with different contents of the various sulfides can be used. TESPT can also be added, for example, as a mixture with carbon black (trade name X50S® from Evonik).

Blocked mercaptosilanes, as z. B. from the WO 99/09036 are known can be used as a silane coupling agent. Also silanes, as in the WO 2008/083241 A1 , the WO 2008/083242 A1 , the WO 2008/083243 A1 and the WO 2008/083244 A1 are described can be used. Can be used e.g. B. silanes under the name NXT in different variants from Momentive, USA, such as in particular 3-octanoylthio-1-propyltriethoxysilane, or those sold under the name VP Si 363® by Evonik Industries.

The proportion of the total amount of further additives is preferably 3 to 150 phr, particularly preferably 3 to 100 phr and very particularly preferably 5 to 80 phr.

Zinc oxide (ZnO) can be contained in the abovementioned amounts in the total proportion of the other additives.

This can be any type of zinc oxide known to those skilled in the art, such as ZnO granules or powder. The conventionally used zinc oxide usually has a BET surface area of less than 10 m ² /g. However, a zinc oxide with a BET surface area of 10 to 100 m ² /g, such as so-called “nano-zinc oxides”, can also be used.

The rubber mixture according to the invention is preferably used in vulcanized form, in particular in vehicle tires or other vulcanized technical rubber articles.

The terms “vulcanized” and “crosslinked” are used synonymously in the context of the present invention.

The vulcanization of the rubber mixture according to the invention is preferably carried out in the presence of sulfur and/or sulfur donors with the aid of vulcanization accelerators, it being possible for some vulcanization accelerators to 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, xanthogenate accelerators and guanidine accelerators. Preferred is the use of a sulfenamide accelerator selected from the group consisting of N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS), benzothiazyl-2- sulfenmorpholide (MBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS) and guanidine accelerators such as diphenylguanidine (DPG).

All sulfur-donating substances known to those skilled in the art can be used as the sulfur-donating substance.

In addition, vulcanization retarders can be present in the rubber compound.

Otherwise, the rubber mixture is preferably prepared by the process customary in the rubber industry, in which a basic mixture with all the components apart from the vulcanization system (e.g. sulfur and substances that influence vulcanization) is first prepared in one or more mixing stages. The finished mixture is produced by adding the vulcanization system in a final mixing stage.

The finished mixture is further processed, e.g. by an extrusion process or calendering, and brought into the appropriate shape.

The rubber mixture according to the invention is particularly suitable for use in vehicle tires, in particular pneumatic vehicle tires. The use in all tire components is conceivable in principle, in particular in an outer component, in particular and preferably in the horn profile, tread strip and/or the sidewall tread strip. In the case of a tread strip with a cap/base construction, the rubber mixture according to the invention is preferably used at least in the cap.

For use in vehicle tires, the mixture is brought into the appropriate form, preferably an outer component, as a ready-to-use mixture before vulcanization and applied in the known manner during the production of the vehicle tire blank.

The rubber mixture according to the invention for use as other body mixture in vehicle tires is produced as already described. The difference lies in the shaping after the extrusion process or the calendering of the mixture. The forms of the still unvulcanized rubber mixture obtained in this way for one or more different body mixtures are then used to build up a green tire.
The rubber mixtures for the inner components of a tire, such as essentially squeegee, inner liner (inner layer), core profile, belt, shoulder, belt profile, carcass, bead reinforcement, bead profile, horn profile and bandage, are referred to as body mixture.

The still unvulcanized green tire is then vulcanized.

To use the rubber mixture according to the invention in belts and belts, in particular in conveyor belts, the extruded, still unvulcanized mixture is brought into the appropriate shape and is often provided with reinforcements, e.g. synthetic fibers or steel cords, either at the same time or afterwards. In most cases, this results in a multi-layer structure consisting of one and/or more layers of rubber mixture, one and/or more layers of the same and/or different reinforcements and one or more other layers of the same and/or another rubber mixture.

A further subject of the present invention is a vehicle tire which has the rubber mixture according to the invention containing the compound according to the invention in at least one component.
At least one component of the vulcanized vehicle tire has a vulcanizate of at least one rubber mixture according to the invention. It is known to those skilled in the art that most substances, e.g. B. the contained rubbers are present or can be present in a chemically modified form either after mixing or only after vulcanization.

In the context of the present invention, vehicle tires are understood to mean pneumatic vehicle tires and solid rubber tires, including tires for industrial and construction site vehicles, truck, passenger car and two-wheeler tires.

The vehicle tire according to the invention preferably has the rubber mixture according to the invention in at least one outer component, the outer component preferably being a tread strip, a side wall and/or a horn profile.

The vehicle tire according to the invention can therefore also have the rubber mixture according to the invention containing the compound according to the invention of the formula I) in a plurality of components in a composition which may have been adapted.

• a1) Bereitstellung der Substanz gemäß Formel A1):
  
• b1) Bereitstellung von Kaliumcarbonat (K₂CO₃) und Dimethylformamid (DMF);
• c1) Umsetzung der Substanz gemäß Schritt a1) in Gegenwart der Substanzen gemäß Schritt b1) zu der Verbindung gemäß Formel C1):
  
• d1) Bereitstellung von Methylisobutylketon (MIBK) sowie Wasserstoff;
• e1) Umsetzung der Verbindung gemäß Formel C1) mit den Substanzen aus Schritt d1) zu der Verbindung gemäß Formel E1):
  
• f1) Bereitstellung eines Reduktionsmittels, insbesondere Boran-Tetrahydrofuran;
• g1) Umsetzung der Substanz aus Schritt e1) mit der Substanz aus Schritt f1) zu der Verbindung gemäß Formel I):
  

Another subject of the present invention is a process for preparing the compound of the formula I), the process comprising at least the following process steps:

• a1) Provision of the substance according to formula A1):
  
• b1) providing potassium carbonate (K ₂ CO ₃ ) and dimethylformamide (DMF);
• c1) Reaction of the substance according to step a1) in the presence of the substances according to step b1) to form the compound according to formula C1):
  
• d1) provision of methyl isobutyl ketone (MIBK) and hydrogen;
• e1) Reaction of the compound of the formula C1) with the substances from step d1) to form the compound of the formula E1):
  
• f1) providing a reducing agent, in particular borane-tetrahydrofuran;
• g1) reaction of the substance from step e1) with the substance from step f1) to form the compound of the formula I):
  

The conversion according to step c1) to 2-nitroacridin-9(1OH)-one takes place in particular according to R. Freyer J. Chem. 1963, 4979-5004.

A suitable catalyst, referred to as “hydrogenation catalyst” in the context of the present invention, is preferably used in the reaction with hydrogen.

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

Furthermore, other known catalysts such as Raney nickel or copper chromite can also be used.

Hydrogen is preferably injected at a pressure of 35 to 45 bar, in particular 40 bar, for example, and stirring is then preferably carried out for 1 to 20 hours, preferably 3 to 13 hours, particularly preferably 5 to 13 hours, in particular 10 hours, for example.

The reaction in step e1) preferably takes place at a temperature of 120 to 150.degree. C., in particular 140.degree. C., for example.

A process according to the invention is preferred in which the reaction in step e1) with hydrogen takes place using a hydrogenation catalyst and/or at a temperature of 80 to 150° C. and/or hydrogen is injected at a pressure of 25 to 45 bar and the reaction takes place in an autoclave or other pressure reactor.

A process according to the invention is particularly preferred in which the reaction in step e1) with hydrogen takes place using a hydrogenation catalyst and at a temperature of 80 to 150° C. and hydrogen is injected at a pressure of 25 to 45 bar and the reaction is carried out in an autoclave or takes place in another pressure reactor.

The solvent in step e1) can either be MIBK, which also serves as a reactant, or an inert solvent such as toluene or xylene. In the latter case, MIBK is only used in stoichiometric amounts as a reactant. However, preference is given to using MIBK as the solvent at the same time. As a result, an additional substance such as toluene or xylene can be dispensed with. In addition, unreacted MIBK can be recovered and reused following the reaction.

After step g1), purification is preferably carried out, for example by column chromatography, for example on silica gel.

The compound of the formula I) according to the invention has an increased reactivity compared to 6PPD. This could be understood, for example, based on the calculation of bond dissociation energies (BDE), as well as the free activation enthalpy Δ _R G ^≠ and the free standard reaction enthalpy Δ _R G° for the reaction with a methyl peroxide radical. The values are given in Table 1. In 1a and 1b shows the splitting mechanisms to which the values refer. Table 1 molecule BDE [kJ/mol] Δ _R Go [kJ ^/ mol] Δ _R G ^≠ [kJ/mol] 6PPD 313 -25.6 19.1 Formally) 267 -37.0 12.3

As Table 1 shows, the compound of the formula I) according to the invention has a lower bond dissociation energy and lower free enthalpies.

An improved protective effect can thus be achieved with the compound of the formula I) in the applications mentioned.

The compound of the formula I) can be prepared, for example, in the manner described above using the process according to the invention.

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

For this purpose, the compound of the formula I) is mixed in, for example, in various amounts, as shown in Table 2. The resulting examples according to the invention are marked E1 and E2. As a comparison, rubber mixtures containing 6PPD serve as aging inhibitors instead of the compound of the formula I) with an otherwise identical composition, with between C1 and E1 and C2 and E2 in each case an exchange of the same moles takes place. The amounts in Table 2 are given in units of phr. A reference (Ref.) without anti-aging agents is also given. For all mixtures, the sum of the amounts of anti-aging agent (6PPD or Formula I) and process oil MES is 10 phr. Table 2 component V1 E1 v2 E2 Ref . NO 100 100 100 100 100 Carbon black N 339 50 50 50 50 50 MES 8th 7.91 5 4.78 10 6PPD 2 - 5 - - compound according to formula I) - 2.09 - 5.22 - ZnO 3 3 3 3 3 stearic acid 2 2 2 2 2 TBBS 1.2 1.2 1.2 1.2 1.2 sulfur 1.2 1.2 1.2 1.2 1.2

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 9909036 [0067]
• WO 2008/083241 A1 [0067]
• WO 2008/083242 A1 [0067]
• WO 2008/083243 A1 [0067]
• WO 2008/083244 A1 [0067]

Claims (12)

compound according to formula I)

Rubber mixture containing the compound according to formula I). claim 1 rubber compound claim 2 , characterized in that it contains at least one diene rubber. rubber compound claim 3 , characterized in that it contains at least one diene rubber selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR), emulsion-polymerized styrene-butadiene -Rubber (ESBR), butyl rubber (IIR) and halobutyl rubber. Vehicle tire, the rubber mixture according to one of claims 2 until 4 has in at least one component. vehicle tires claim 5 , characterized in that it comprises at least one rubber mixture according to one of claims 2 until 4 in at least one outer component, the outer component preferably being a tread, a sidewall and/or a horn profile. Process for the preparation of the compound of the formula I) according to claim 1 comprising at least the following process steps: a1) providing the substance of the formula A1):

b1) providing potassium carbonate (K ₂ CO ₃ ) and dimethylformamide (DMF); c1) Reaction of the substance according to step a1) in the presence of the substances according to step b1) to form the compound according to formula C1):

d1) provision of methyl isobutyl ketone (MIBK) and hydrogen; e1) Reaction of the compound of the formula C1) with the substances from step d1) to form the compound of the formula E1):

f1) providing a reducing agent, in particular borane-tetrahydrofuran; g1) reaction of the substance from step e1) with the substance from step f1) to form the compound of the formula I):

procedure after claim 7 , wherein the reaction in step e1) with hydrogen using a hydrogenation catalyst and / or at a temperature of 80 to 150 ° C and / or hydrogen is injected at a pressure of 25 to 45 bar and the reaction in an autoclave or in a another pressure reactor takes place. Use of the compound according to formula I) after claim 1 as an anti-aging agent and/or anti-ozone agent, in particular in vehicle tires and/or other 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 robot applications, or a shoe sole or parts thereof, and/or oils and/or lubricants. Use of the compound according to formula I) after claim 1 for the manufacture of a rubber article, in particular an air spring, a bellows, a conveyor belt, a 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. Use of the compound according to formula I) after claim 1 in oils, lubricants, such as in particular fuels or operating materials for engines. Use of the compound according to formula I) after claim 1 as a dye in fibers and/or polymers and/or paper and/or in (coating) paints and varnishes.

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