Commercial vehicle tires

Abstract

The invention relates to a commercial vehicle tire of radial design with an airtight inner layer (1), which may optionally be combined with a filler profile (11), a horn profile (3), a single- or multi-layer carcass insert (4) with reinforcing elements made of steel cord or a material of similar strength, wherein the carcass insert (4) is folded around bead cores (5) in bead areas to form carcass folds (4a), wherein in each bead area a steel cord bead reinforcement (9) runs on the outside of the carcass insert (4), which surrounds the bead area and has a section (9a) extending on the outside of the tire and a section (9b) extending on the inside of the tire, wherein there is a gap between the inner layer (1) and the inner layer (1).Between the filling profile (11) and the section (9b) of the steel cord bead reinforcement (9) running inside the tire and the section of the carcass insert (4) adjoining this section (9b) in a radial direction, at least one reinforcement layer (12) having textile reinforcing elements embedded in a rubber compound is arranged, the reinforcing elements of which run parallel to the reinforcing elements in the carcass insert, wherein the horn profile is made of a sulfur-crosslinkable rubber compound of a specified composition.

Description

[0001] The invention relates to a commercial vehicle tire of radial design with an airtight inner layer, which may optionally be combined with a filler profile, a single- or multi-layer carcass ply with reinforcing elements made of steel cord or a material of similar strength, wherein the carcass ply is folded around bead cores in bead areas to form carcass folds, wherein in each bead area a steel cord bead reinforcement runs on the outside of the carcass ply, which surrounds the bead area and has a section running on the outside of the tire and a section running on the inside of the tire, wherein between the inner layer orBetween the filling profile and the section of the steel cord bead reinforcement running inside the tire and the section of the carcass insert that adjoins this section in a radial direction, at least one reinforcement layer having textile reinforcement carriers embedded in a rubber compound is arranged, the reinforcement carriers of which run parallel to the reinforcement carriers in the carcass insert.

[0002] A commercial vehicle tire of the type mentioned above is known from WO 2016 / 005084 A1, but there it is limited to the design as a slant shoulder tire.

[0003] The increasing electrification of the commercial vehicle sector is placing ever higher demands on the design and performance of tires. Commercial vehicles converted to electric mobility are generally heavier than their conventional, combustion engine-powered counterparts. This weight increase is primarily due to the large and heavy batteries required for electric drive. The additional weight leads to increased stress on the tires, resulting in higher rolling resistance, more intense heat generation, and faster wear.

[0004] The tire's rim profile plays a crucial role in this context, as it is subjected to considerable stress. The additional weight of the vehicles and the specific loads from the electric drive, such as instantaneous torque and regenerative braking energy, significantly increase the forces acting on the rim profile. This component zone, responsible for the connection between the tire and the rim, is central to load transfer and is subjected to considerable stress by the heavier electric vehicles.

[0005] While the rim profile already represents a critical zone on conventional commercial vehicles, the increased stress on electric commercial vehicles leads to a heightened risk of deformation or structural weaknesses. The rim profile is subjected to additional stress, particularly during tire removal for retreading, as the tire must be repeatedly removed from and remounted on the rim. This process exposes the rim profile to high mechanical stresses, which can lead to premature wear or weakening of the profile. Especially if the tire has already been subjected to additional stresses due to extra loads and regenerative braking, this can result in massive and often irreparable damage to the rim profile.

[0006] In view of these challenges, the focus is on the further development of the horn profile for electrically powered commercial vehicles in order to better withstand the higher loads and thermal stress.

[0007] Furthermore, the sustainability of tire use is gaining importance. Retreading represents an environmentally friendly alternative to the complete production of new tires, as it reuses the carcass and only renews the tread. However, this process is particularly challenging for electric commercial vehicles. The wear and accelerated aging caused by the higher weight and increased heat generation place greater demands not only on the carcass and tread, but especially on the bead profile, which is subjected to particular stress during retreading. Improvements in the choice of bead profile materials are therefore crucial to extending the service life of retreaded tires and meeting the requirements of electromobility.

[0008] The object of the present invention is to provide a tire, particularly for electrically powered commercial vehicles, that withstands the increased mechanical and thermal loads resulting from the additional vehicle weight and the specific conditions of the electric drive. In particular, the tire bead should be designed to maintain its structural integrity even under these increased loads and to withstand the specific requirements of retreading without premature wear or deformation.

[0009] Furthermore, the aim is to extend the overall lifespan of the tire, increase its thermal stability, and enable sustainable use through multiple retreadings in order to meet the growing demands for efficiency and environmental friendliness in the commercial vehicle sector.

[0010] In a commercial vehicle tire of the type mentioned above, at least one reinforcement layer embedded in a rubber compound and containing textile reinforcing elements is arranged between the inner layer or between the filler profile and the section of the steel cord bead reinforcement running along the inside of the tire, and the section of the carcass ply that adjoins this section in the radial direction. The reinforcing elements of this layer run parallel to the reinforcing elements in the carcass ply. Due to its placement on the inside of the tire and the fact that its reinforcing elements run parallel to the reinforcing elements in the carcass ply, the reinforcement layer(s) ensure(s) particularly high load-bearing capacity and high mileage. In the areas of the tire near the rim, defects caused by the cut edges of conventional bead reinforcements are avoided.Furthermore, tires designed in this way can be manufactured cost-effectively and efficiently due to their construction.

[0011] However, such a commercial vehicle tire requires further optimization measures, especially if it is intended for electrically powered commercial vehicles, to withstand the increased mechanical and thermal stresses resulting from the additional vehicle weight and the specific conditions of the electric drive. The additional reinforcement layer(s) alone would not significantly improve durability and, in particular, retreadability, as the defect pattern would simply shift to the comparatively weaker bead profile. If this is not also optimized according to the invention, no significant improvement in bead durability and retreadability is achieved under constant load. Due to the higher loads resulting from electrification, bead durability and retreadability would not improve despite the additional reinforcement layer(s) and could even worsen.The goal of extending the overall service life of the tire, increasing thermal stability and enabling sustainable use through multiple retreadings is achieved through the particularly advantageous combination of the design described in WO 2016 / 005084 A1 with further adaptations according to the invention.

[0012] In particular, the focus here is on the horn profile of the tire, which must be designed in such a way that it retains its structural integrity even under these increased loads and withstands the specific requirements of retreading without premature wear or deformation.

[0013] This is solved by optimizing the sulfur-crosslinkable rubber compound for the horn profile.

[0014] According to the invention, the horn profile is made from a sulfur-curable rubber compound containing at least the following components: - at least one diene rubber, - 40 to 90 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one carbon black, wherein the carbon black or blacks have a weighted average iodine value according to ASTM D 1510 of 55 to 80 g / kg, - 5 to 20 phr of at least one silica, - at least a silane coupling agent and - an efficient vulcanization system containing at least one vulcanization accelerator and elemental sulfur, wherein the mass ratio of vulcanization accelerator to sulfur is 8:1 to 3:1.

[0015] This also extends the overall lifespan of the tire, increases thermal stability and enables sustainable use through multiple retreadings, thus meeting the growing demands for efficiency and environmental friendliness in the commercial vehicle sector.

[0016] Rolling resistance and durability are known to be influenced by the type and quantity of fillers used and by the crosslinking system. Rubber compounds in vehicle tires are generally reinforced with fillers, typically carbon black and / or silica. Switching to a carbon black with a lower surface area, for example, generally leads to a reduction in hysteresis (correlated with an improvement in rolling resistance), but simultaneously to a deterioration of properties important for durability. Conversely, switching from a carbon black with a lower surface area to one with a higher surface area results in worse hysteresis but improved durability.

[0017] The term "sulfur-cured rubber compound" refers to a rubber compound produced from a finished rubber compound (or raw rubber compound) through sulfur vulcanization. A sulfur-cured rubber compound is therefore a vulcanizate. Unless otherwise specified, the description of the individual components refers to the rubber compound before vulcanization, i.e., the sulfur-curable rubber compound.

[0018] It is clear to the expert that the components may be in a changed form after vulcanization, which applies in particular to the rubbers (polymers), sulfur and other components involved in vulcanization.

[0019] Rubber compounds for vehicle tires are typically crosslinked with sulfur, with the ratio of vulcanization accelerator to sulfur determining the efficiency of the sulfur network. A low ratio of vulcanization accelerator to sulfur, i.e., below 1:2, indicates conventional vulcanization and results in long sulfur chains. A high ratio indicates an efficient vulcanization system with shorter sulfur chains. Increasing the efficiency of the sulfur network generally improves durability (aging resistance), but increases rolling resistance.

[0020] High durability, especially resistance to aging, is crucial, particularly in the bead area of ​​pneumatic tires, as this area is subject to high mechanical and thermal stresses. At the same time, tire rolling resistance must be continuously reduced. However, areas of the pneumatic tire that are particularly stressed include – as mentioned – the rim profiles, also known as rim tape or bead protection strips, which are partially in direct contact with the outside air.

[0021] Surprisingly, it has been found that the specific combination of one or more carbon blacks, whose iodine value is between 55 and 80 g / kg on a weighted average, with a small amount of silica and a silane coupling agent and with a special efficient vulcanization system, each in the specified quantities in diene rubber mixtures, leads to a high durability of the vulcanizates through improved aging resistance, while simultaneously reducing hysteresis.

[0022] 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 each substance is always based on 100 parts by weight of the total mass of all solid rubber components present in the mixture.

[0023] According to the invention, the rubber mixture contains at least one diene rubber. Diene rubbers are rubbers formed by the polymerization or copolymerization of dienes and / or cycloalkenes and thus exhibit C=C double bonds either in the main chain or in the side chains. The diene rubbers can be functionalized, modified, or coupled.

[0024] The diene rubber(s) is / are preferably selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), epoxidized polyisoprene (ENR), butadiene rubber (BR), butadiene-isoprene rubber, styrene-butadiene rubber (SBR), in particular solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR), styrene-isoprene rubber, liquid rubbers with a molecular weight M wof greater than 20000 g / mol, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluororubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile butadiene rubber and hydrogenated styrene-butadiene rubber.

[0025] In particular, nitrile rubber, hydrogenated acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber, 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—specifically with regard to fillers, plasticizers, vulcanization systems, and additives.

[0026] According to a particularly preferred embodiment of the invention, the diene rubber(s) is / are 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). Natural polyisoprene is understood to be rubber that can be obtained by harvesting from sources such as rubber trees (Hevea brasiliensis) or non-rubber tree sources (such as guayule or dandelion (e.g., Taraxacum koksaghyz)). Natural polyisoprene (NR) is understood to mean non-synthetic polyisoprene.

[0027] The butadiene rubber (= BR, polybutadiene) optionally contained in the rubber compound according to the invention 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.

[0028] The polybutadiene(s) used may be end-modified and / or functionalized along the polymer chains. These modifications may involve hydroxyl 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 a qualified professional. Such functionalizations may include metal atoms.

[0029] 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.

[0030] 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.

[0031] For use in the bead-proximal areas of a vehicle pneumatic tire, the rubber compound preferably contains 20 to 50 phr of natural rubber (NR) and 50 to 80 phr of at least one butadiene rubber (BR).

[0032] The rubber compound according to the invention contains 40 to 90 phr, preferably 50 to 80 phr, of at least one carbon black, wherein the carbon black or blacks have an average iodine value according to ASTM D 1510 of 55 to 80 g / kg. Accordingly, a carbon black with an iodine value according to ASTM D 1510 of 55 to 80 g / kg can be used in the compound, for example, carbon black of type N351 (iodine value: 68 g / kg). However, it is also possible to use two or more carbon blacks in the compound such that an average iodine value according to ASTM D 1510 of 55 to 80 g / kg is obtained. In this case, a blend of several carbon blacks is used.

[0033] The rubber compound contains 5 to 20 phr of at least one silica compound. Any silica compound known to those skilled in the art can be used, including those suitable for use in mixtures. Preferably, silica compounds with a nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132) of 35 to 400 m² are used. 2 / g, and a CTAB surface area (according to ASTM D 3765) of 30 to 400 m² 2 / g. Suitable silicas include, for example, those of the Ultrasil® VN3 type (trade name) from Evonik, as well as silicas such as Zeosil® 1115 or Zeosil® 1085 from Solvay, and highly dispersible silicas, so-called HD silicas (e.g., Zeosil® 1165 MP from Solvay). To improve the mixture in terms of sustainability, it is preferable to include silica produced from rice husk ash (“rice husk ash silica” (RHAS)) in the mixture.

[0034] It is advantageous if the reinforcement layer(s) extends from a height of 20 mm to 60 mm, particularly from 25 mm to 45 mm, up to a height of 40 mm to 150 mm, particularly from 50 mm to 110 mm, with the heights being measured radially from a line running axially through the rim corner. Such a reinforcement layer distributes the deformation occurring during tire rotation more harmoniously over the entire height of the bead above the bead core, i.e., radially outward relative to the bead core, thereby achieving particularly good durability in the radially outer areas of the bead compared to the bead core. However, the use of such a reinforcement layer does not have a positive effect on the durability of the bead profile in the radially innermost section of the bead profile near the bead core, which is crucial for mounting.Consequently, the detection of damage patterns in the upper region of the bead shifts to the lower regions of the bead, and particularly under higher loads, no sufficient improvement in bead durability is achieved. Conversely, without such a reinforcing layer(s), but using the inventive horn profile compound, an improvement in the durability of the horn profile is achieved, particularly in the radially innermost section of the horn profile near the bead core. However, this leads to a shift of the defect pattern towards the upper regions of the bead, which, particularly under higher loads, does not improve retreadability. Only the inventive combination of such a reinforcing layer(s) with the inventive rubber compound results in a significant improvement in bead durability, since both regions of the bead essential for retreadability are optimized for durability.Although the individual measures do not lead to an improvement in durability compared to a tire with a conventional horn profile and bead construction under normal load, the combination surprisingly leads to an improvement in durability and thus ensures better retreadability despite the high demands that electrification places on tires.

[0035] The use of the commercial vehicle tire according to the invention on a 15° drop-center rim standardized according to ETRTO standards with a width code of 5.25 to 18.00 is particularly advantageous. The commercial vehicle tire is specifically designed for mounting on a 15° drop-center rim, which, according to the European Tyre and Rim Technical Organisation Standards Manual (“ETRTO Standards”) in its currently valid version (October 2024), section 15° Drop-Center Rims (width codes 5.25 to 18.00), is designed with nominal diameters of 17.5 inches, 19.5 inches, 20.5 inches, 22.5 inches, or 24.5 inches.

[0036] With regard to a slant-shoulder tire as a commercial vehicle tire - as known from WO 2016 / 005084 A1 - it may be particularly advantageous if the reinforcement layer(s) extend from a height of 40 mm to 60 mm, in particular from 45 mm to 55 mm, up to a height of 100 mm to 150 mm, in particular from 120 mm to 140 mm, wherein the heights are measured in the radial direction from a line extending in the axial direction through the rim corner.

[0037] It is advantageous if the rubber compound of the reinforcement layer(s) contains silica, particularly as a filler, which is preferably produced from rice husk ash (“rice husk ash silica” (RHAS)), especially with regard to sustainability.

[0038] It can be advantageous if the sulfur-curable rubber compound of the horn profile and / or the rubber compound of the reinforcement layer (12) contains silica in an amount of 5 phr to 50 phr, preferably in an amount of 6 phr to 30 phr, and particularly preferably in an amount of 7 phr to 20 phr. The addition of silica also ensures optimal adhesion between the textile reinforcement elements and the rubber matrix, as well as improving the tear resistance of the rubber, thereby contributing to a particularly high service life for the reinforcement layer(s), even under high loads.

[0039] In order to further increase the sustainability of commercial vehicle tires, in addition to increased retreadability and the advantageous use of RHAS, it may be advantageous if the sulfur-crosslinkable rubber compound of the horn profile and / or the rubber compound of the reinforcement layer contains at least 5 phr, preferably at least 10 phr, particularly preferably at least 15 phr of recycled materials.

[0040] According to the invention, recycled materials include all commonly used or novel recycled materials in industry, such as recovered carbon blacks (r-CB), regenerates from used tires and other used rubber articles (e.g., conveyor belts, V-belts, hoses) or plastic articles, as well as products from pyrolysis processes, including pyrolysis oil (TPO) and materials obtained therefrom such as light and heavy oils, carbon blacks (s-CB), resins (s-Resins) and process aids (s-Plasticizer).

[0041] To improve processability and to bind the silica to the diene monomer rubber of the mixtures, at least one of the mixtures contains at least one silane coupling agent, which is preferably used in amounts of 1–15 pph (parts by weight, based on 100 parts by weight of silica / silica) in the rubber mixture. The silane coupling agents can also be used in the mixture and / or differ between the mixtures.

[0042] The unit pph (parts per hundred parts of filler by weight) used in this document is the quantity commonly used in the rubber industry for coupling agents for polar fillers. In the context of this application, pph refers to the silica / silicic acid present, meaning that other fillers that may be present, such as carbon black, are not included in the calculation of the quantity of silane coupling agent.

[0043] The silane coupling agents react with the surface silanol groups of silica or other polar groups during the mixing of the rubber or rubber compound (in situ) or even before the addition of the filler to the rubber as a pretreatment (pre-modification). Any silane coupling agents known to those skilled in the art for use in rubber compounds can be used as such. Such coupling agents known from the prior art are bifunctional organosilanes that have at least one alkoxy, cycloalkoxy, or phenoxy group as a leaving group on the silicon atom and that possess, as a further functionality, 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. x- (with x = 2-8). Thus, silane coupling agents can 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, or mixtures of the sulfides with 1 to 8 sulfur atoms and varying concentrations of the different sulfides. TESPT can also be added, for example, as a mixture with carbon black (trade name X50S from Degussa). 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. For example, silanes marketed under the name NXT are suitable. ®Various versions are available from the company Momentive, USA, or those marketed under the name VP Si 363 by Evonik Industries. So-called "silated core polysulfides" (SCP, polysulfides with a silylated core), described, for example, in US 20080161477 A1 and EP 2 114 961 B1, can also be used.

[0044] The rubber compound may contain other fillers, such as aluminosilicates, kaolin, chalk, starch, magnesium oxide, titanium dioxide, rubber gels, and fibers (such as aramid fibers, glass fibers, carbon fibers, cellulose fibers), carbon nanotubes (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, graphene, or so-called "carbon-silica dual-phase fillers" in typical quantities, whereby the fillers may be used in combination.

[0045] A key feature of the invention is that the rubber compound has an efficient vulcanization system comprising at least one vulcanization accelerator and elemental sulfur, wherein the mass ratio of vulcanization accelerator to sulfur is 8:1 to 3:1, preferably 7:1 to 3:1, and particularly preferably 6:1 to 3.5:1. This enables crosslinking with short sulfur chains to form an efficient network.

[0046] The vulcanization accelerator(s) can be selected from all vulcanization accelerators known to those skilled in the art for sulfur vulcanization. These accelerators include thiazole accelerators, mercapto accelerators, sulfenamide accelerators, sulfenimide accelerators, thiocarbamate accelerators, thiuram accelerators, thiophosphate accelerators, thiourea accelerators, xanthate accelerators, and guanidine accelerators. For particularly good durability and low rolling resistance, the vulcanization accelerator(s) is preferably selected from the group consisting of mercapto accelerators, sulfenamide accelerators, sulfenimide accelerators, and guanidine accelerators.

[0047] According to an advantageous embodiment of the invention, the sulfur-crosslinkable rubber compound contains at least TBSI (N-tert-butyl-2-benzothiazole sulfenimide) and / or TBBS (N-tert-butyl-2-benzothiazole sulfenamide) and / or DCBS (N,N-dicyclohexyl-2-benzothiazole sulfenamide) and / or CBS (N-cyclohexyl-2-benzothiazole sulfenamide) as a vulcanization accelerator.

[0048] All vulcanization accelerators can also be used in mixtures.

[0049] For good aging resistance of the vulcanizates, the rubber mixture preferably contains 0.5 to 1.5 phr sulfur.

[0050] Furthermore, the rubber compound may contain vulcanization retarders.

[0051] The terms “vulcanized” and “crosslinked” are used synonymously within the scope of the present invention.

[0052] The rubber compound according to the invention may further contain various plasticizers. These are preferably present in quantities of up to 50 phr in the compound.

[0053] Suitable plasticizers include, for example, those selected from the group consisting of plasticizers derived from renewable raw materials such as rapeseed oil or sunflower oil, or rubber-to-liquid (RTL) or biomass-to-liquid (BTL) oils, preferably with a polycyclic aromatic hydrocarbon content of less than 3 wt% according to method IP 346, or in particular resin acids or factisse or liquid polymers whose mean molecular weight (determined by GPC = gel permeation chromatography, in accordance with BS ISO 11344:2004) is between 500 and 20000 g / mol, mineral oils, phosphoric acid esters such as tri(2-ethylhexyl) phosphate, and liquid polymers with a weight-average molecular weight distribution M waccording to GPC of 60,000 g / mol or less. If additional liquid polymers are used as plasticizers in the rubber compound according to the invention, these are not included as rubber in the calculation of the polymer matrix composition. Preferably, DAE (Distilled Aromatic Extracts), RAE (Residual Aromatic Extract), TDAE (Treated Distilled Aromatic Extracts), MES (Mild Extracted Solvents), rapeseed oil and / or liquid diene polymers are used.

[0054] 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, such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), N,N'-di(1,4-dimethylpentyl)-p-phenylenediamine (77PD), N,N'-di(1-ethyl,4-methyl-hexyl)-p-phenylenediamine (88PD), N,N'-bis-(1-ethyl-3-methylpentyl)-p-phenylenediamine (DOPD), N,N'-di-β-naphthyl-p-phenylenediamine (DNPD), and 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ). b) Activators, such as zinc oxide (e.g., ZnO granules or powder; conventionally used zinc oxide typically has a BET surface area of ​​less than 10 m²). 2 / g. However, it can also be a zinc oxide with a BET surface area of ​​10 to 100 m². 2 / g, such as so-called “nano-zinc oxides”, are used) and fatty acids (e.g. stearic acid) or zinc complexes such as zinc ethylhexanoate, c) Resins, such as phenolic resins, in particular adhesive resins. Natural or synthetic resins, such as hydrocarbon resins, can be used as adhesive resins, acting as tackifiers. The hydrocarbon resins can be phenolic, aromatic, or aliphatic. Preferably, the adhesive resins are selected from the group consisting of rosin resins and their esters, terpene phenolic resins, alkyne phenolic resins, phenolic resins, and coumaron indene resins, with phenolic resins being particularly well suited for the present invention. d) Mastication aids, such as 2,2'-dibenzamidodiphenyl disulfide (DBD), and e) Processing aids, such as fatty acid salts, such as zinc soaps, and fatty acid esters and their derivatives.

[0055] The quantity of other additives in the total quantity is 3 to 150 phr, preferably 3 to 100 phr and particularly preferably 5 to 80 phr.

[0056] The rubber compound is produced according to a process customary in the rubber industry, in which a base mixture containing all components except the vulcanization system (sulfur and vulcanization-influencing substances) is first prepared in one or more mixing stages. The finished mixture is then produced by adding the vulcanization system in a final mixing stage. This finished mixture is further processed, for example, by extrusion, and formed into the desired shape. Subsequent processing is carried out by vulcanization, whereby sulfur crosslinking occurs due to the vulcanization system added within the scope of the present invention.

[0057] This rubber compound can be used for a wide variety of rubber products where low hysteresis and high durability and aging resistance are advantageous. It is preferably used in the manufacture of vehicle tires, such as car, van, truck, or motorcycle tires. It can be used in various components of vehicle tires, especially pneumatic tires. These components can include, for example, compounds in the bead and sidewall areas, such as the apex, parts of the apex, parts of the sidewall, or crescent-shaped inserts in the sidewall area.

[0058] According to the invention, the rubber compound is used as a rim profile for commercial vehicle tires. Tires with a rim profile made from the compound according to the invention are characterized by low rolling resistance and high durability.

[0059] In the production of commercial vehicle tires, the mixture is brought into the shape of the relevant component, namely the horn profile, as a ready-made mixture before vulcanization and applied as usual during the production of the vehicle tire blank.

[0060] 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, for example, components of the rubber compound, and different degrees of preference given to these features, such that a combination of a first feature designated as "preferred" or described within the framework of an advantageous embodiment with a further feature designated, for example, as "particularly preferred," is also covered by the invention.

[0061] The invention will now be explained in more detail with reference to comparative and exemplary embodiments, which are summarized in Table 1.

[0062] The comparison mixtures are marked with V, the mixture according to the invention is marked with E.

[0063] The compound was prepared according to standard rubber industry procedures under typical conditions in three stages using a laboratory mixer. In the first two stages (basic mixing stages), all components except the vulcanization system (sulfur and vulcanization-influencing substances) were mixed. The final compound was then produced by adding the vulcanization system in the third stage (final mixing stage), with mixing taking place at 90 to 120 °C.

[0064] Test specimens were produced from all mixtures by vulcanization for 15 minutes under pressure at 160 °C, and material properties typical for the rubber industry were determined using these test specimens with the test procedures specified below: - Network node spacing according to differential scanning calorimetry: This method utilizes the fact that the liquid-solid phase transition of a swelling agent within a swollen polymer network depends on the crosslinking density. Samples of the respective rubber compound are swollen with cyclohexane as a swelling agent; for this purpose, the respective sample is extracted with cyclohexane and then allowed to swell further at room temperature (RT). Subsequently, the freezing point depression of cyclohexane in the network is determined in comparison to the macroscopically extended liquid phase: The prepared sample is cooled in the measuring apparatus and the heat flux is recorded. Two freezing peaks are obtained: the peak of pure cyclohexane at approximately 3°C and another peak of the cyclohexane present in the swollen sample.

[0065] The network node spacing is calculated from the temperature difference. - Shore A hardness at room temperature according to ISO 868 - Rebound elasticity at 70 °C according to ISO 4662 - Elongation at break at room temperature according to DIN 53504 with test specimen type R1.

[0066] The samples were measured before and after aging: aging in air for 14 days at 80 °C. - Fatigue crack resistance (fatigue fracture life) as the number of load cycles in kilocycles (kC) until failure of a dumbbell-shaped specimen with a thickness of 1.35 to 1.55 mm and a length and width of 230 mm * 76 mm (based on a standard bar S2 described in DIN 53504) under a continuously repeating strain cycle at a frequency of 10⁴ ± 8 min⁻¹, determined using a Monsanto Fatigue to Failure Tester (FTF) at room temperature (RT, 23 °C ± 2 °C). Six specimens of a rubber compound are measured, and the load cycles achieved for each are used to calculate the median for each compound. The median represents the test result for each compound, as shown in Table 1. The specimens were measured before and after aging. Aging was carried out in air for 14 days at 80 °C. The unaged samples were measured at a prestress of 89%, the aged samples at a prestress of 61%.

[0067] High rebound elasticity at 70 °C (equivalent to reduced hysteresis) can be correlated with low rolling resistance when the compound is used in vehicle tires. Furthermore, the reduced hysteresis results in less heat generation, allowing the tread profile to run cooler and therefore age more slowly, which has a positive effect on durability. Table 1 Components Unit 1(V) 2(V) 3(V) 4(V) 5(V) 6(E) natural rubber phr 30 30 30 30 30 30 BR a phr 70 70 70 70 70 70 Soot N339 b phr 70 70 0 62 0 0 Soot N351 c phr 0 0 66,5 0 57 57 Silica d phr 0 0 0 10 10 10 Silane clutch agent e phr 0 0 0 0,72 0,72 0,72 Plasticizer oil phr 5 5 5 5 5 5 zinc oxide phr 3 3 3 3 3 3 Stearic acid phr 2 2 2 2 2 2 Anti-aging agents phr 3 3 3 3 3 3 Ozone protection wax phr 2 2 2 2 2 2 Adhesive resin phr 5 5 5 5 5 5 TBBS f phr 2,5 4,3 2,5 3,5 3,5 5,3 sulfur phr 2,5 1,01 2,5 2,5 2,5 1,01 Characteristics Network node spacing nm 4,2 3,7 3,0 3,7 3,6 3,8 Shore hardness at RT Shore A 73,6 72,3 75,8 75,0 73,9 73,3 Rebound strength at 70 °C % 58,6 57,8 64,0 59,7 62,8 61,2 Elongation at break (unrestrained) % 225 208 153 204 211 226 Elongation at break (aged) % 106 151 95 93 104 138 Fatigue crack resistance (unrestricted) kC 69 101 8 25 38 87 Fatigue crack resistance (aged) kC 14 20 1 15 5 70 a high-cis polybutadiene rubber b Carbon black N339, iodine value: 90 g / kg c Carbon black N351, iodine value: 68 g / kg d Ultrasil ® VN3, Evonik, nitrogen surface area = 180 m² 2 / g, CTAB 165 m 2 / G e TESPD (3,3'-Bis(triethoxysilylpropyl)disulfide), Si266, Evonik f N-tert-Butyl-2-benzothiazylsulfenamid

[0068] The data in Table 1 show the effects of the individual measures: efficient vulcanization system only (2(V)), carbon black with medium iodine value only (3(V)), silica with silane coupling agent only (4(V)), and the combined measure of carbon black with medium iodine value and silica with silane coupling agent (5(V)). None of the comparison compounds simultaneously achieves high durability even after aging (evident from the elongation at break values) while maintaining low rolling resistance (deducible from the rebound elasticity values ​​at 70 °C).

[0069] Only the special compound 6(E) can resolve this conflict of objectives in a surprising way. Rebound elasticity at 70 °C and elongation at break, with and without aging, behave in a way that far exceeds the expected effects of the respective individual measures.

[0070] A significant improvement in durability is also evident in the markedly improved fatigue crack resistance, particularly after aging. The sample made from the special mixture 6(E) withstood significantly more load cycles after aging at 70 kC than all other samples, which was unexpected.

[0071] If a single reinforcement layer is provided, it is advantageous for the most optimal stiffening of the radially outer area of ​​the bead area if the radial distance between the end of the section of the steel cord bead reinforcement running inside the tire and the radially inner end of the reinforcement layer is at least 12 mm.

[0072] In further embodiments of the invention, up to four interconnected reinforcement layers can be provided, wherein at least two of these reinforcement layers overlap the end section of the inner section of the steel cord bead reinforcement such that the radial distances between the end of the inner section of the steel cord bead reinforcement and the radially inner ends of the reinforcement layers are at least 15 mm. A vehicle tire constructed in this way proves to be particularly resistant to loads.

[0073] Further features, advantages and details are now explained in more detail with reference to the drawing according to WO 2016 / 005084 A1. This shows

[0074] Fig.1 a cross-section through one of the bead areas of a commercial vehicle tire, which in the embodiment shown, but not limited to, is designed as a slant-shoulder tire, with an embodiment of the invention.

[0075] The following heights h i (i = 1 to 3) are measured radially from a line running axially through the rim corner X.

[0076] In Fig.Figure 1 shows the components of a commercial vehicle tire: an airtight inner layer 1, a sidewall 2, a bead profile 3, a single- or multi-layered carcass ply 4 with steel cords or a material of similar strength as reinforcing elements, a bead core 5 consisting of tensile steel wires, and two core profiles 6 and 7 mounted on the bead core 5. The sidewall 2 typically overlaps the bead profile 3 on its outer side. The core profiles 6 and 7 can be made of identical or different rubber compounds. A core flap 8 made of reinforcing elements, preferably textiles, embedded in rubber is wrapped around the bead core 5 in such a way that it separates the carcass ply 4, which comes from the belt (not shown) and is folded from the inside out around the bead core 5, from the bead core 5, thus preventing direct contact between the carcass ply 4 and the bead core 5. The carcass insert 4 ends axially on the outside as carcass high edge 4a next to the core profile 7.

[0077] A steel cord bead reinforcement 9 extends axially outside the carcass ply 4 and in contact with it. This reinforcement consists of essentially parallel steel cords embedded in rubber and oriented essentially in the circumferential direction of the vehicle tire. The steel cord bead reinforcement 9 has an outer tire section 9a, an inner tire section 9b, and a central section 9c connecting these two sections and extending radially within the bead core 5. Section 9a terminates radially within the carcass rib 4a, and section 9b terminates radially at a height h1 of 25 mm to 70 mm, preferably 35 mm to 65 mm.

[0078] A bead outer profile 10 is arranged between the outer section 9a of the steel cord bead reinforcement 9 and the horn profile 3. The bead outer profile 10 extends radially beyond the section 9a of the steel cord bead reinforcement 9 and the carcass high-profile 4a, and then terminates between the sidewall 2 and the core profile 7. The bead outer profile 10 preferably consists of the same rubber compound as the core profile 7.

[0079] A filling profile 11, also referred to as a cap in the technical literature, extends axially within and in contact with the inner layer 1, wherein the filling profile 11 and the inner layer 1 are combined tire components. However, in a different embodiment than the one shown, only the inner layer 1 and no filling profile 11 may be present.

[0080] On the inner side of the tire, a reinforcement layer 12 is arranged axially outside the carcass ply 4. The reinforcement layer 12 consists of textile reinforcement elements embedded in rubber, which run parallel to the reinforcement elements of the carcass ply 4. Examples of textile reinforcement elements include nylon, perlon, rayon, polyester, or aromatic polyamides, and the textile materials within the reinforcement layer 12 can be used in combination with one another.

[0081] The reinforcement layer 12 extends radially, starting at a height h2, between the filler profile 11 and the steel cord bead reinforcement 9 and overlaps the end of section 9b of the steel cord bead reinforcement 9, which is located at height h1.

[0082] Radially outside section 9b, the reinforcement layer 12 extends in contact with the carcass insert 4 in a radial direction up to a height h3. The height h2 is 20 mm to 60 mm, preferably 25 mm to 45 mm, and the height h3 is 40 mm to 150 mm, preferably 50 mm to 110 mm. The difference between the heights h1 and h2 is defined as a radial distance d1, which is at least 12 mm.

[0083] In contrast to the embodiment shown, two to four reinforcement layers 12 can be present, which are connected to each other via the rubber matrix in which the strength carriers of the reinforcement layers 12 are embedded.

[0084] The reinforcement layers 12 can be arranged in any staggered arrangement relative to each other.

[0085] If two reinforcement layers 12 are provided, both overlap the end of section 9b of the steel cord bead reinforcement 9. If more than two reinforcement layers 12 are provided, at least two of the reinforcement layers 12 overlap the end of section 9b of the steel cord bead reinforcement 9. The reinforcement layers 12 that do not overlap section 9b extend radially, starting at a height greater than h1 and along the carcass ply 4. The radially inner ends of the reinforcement layers 12 have radial distances of ≥ 12 mm from the end of section 9b of the steel cord bead reinforcement 9.

[0086] The rubber or rubber compound underlying the rubber matrix of the textile reinforcement layer(s) 12 preferably contains carbon black as a filler.

[0087] The rubber component in the rubber or rubber compound of the reinforcement layer 12 can be natural rubber and / or synthetic rubbers, for example, butyl rubbers or styrene-butadiene rubbers. Furthermore, the rubber compound contains the usual components, such as plasticizers, activators, sulfur or sulfur donors, accelerators, and other additives, such as antioxidants and masticating agents.

[0088] Between the outer bead profile 10 and the core profile 7 is a rubber profile 13, which covers both the end of the outer section 9a of the steel cord bead reinforcement 9 and the carcass high edge 4a. Another rubber profile 14 covers the end of the inner section 9b of the steel cord bead reinforcement 9 and is located between the reinforcement layer 12 and the carcass ply 4. Reference number list 1 inner layer 2 side wall 3 Horn profile 4 Carcass insert 4a Carcass high impact 5 bead core 6 Core profile 7 Core Profile 8 core flag 9 steel cord bead reinforcements 9a outer tire section of the steel cord bead reinforcement 9b inner tire section of the steel cord bead reinforcement 9c middle section of the steel cord bead reinforcement 10 Outer bead profile 11 Fill profile 12 Reinforcement layer 13 Rubber profile 14 Rubber profile h1 to h3 height d i radial spacing QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] WO 2016 / 005084 A1 [0002, 0011, 0036, 0073] WO 99 / 09036

[0043] WO 2008 / 083241 A1

[0043] WO 2008 / 083242 A1

[0043] WO 2008 / 083243 A1

[0043] WO 2008 / 083244 A1

[0043] US 20080161477 A1

[0043] EP 2 114 961 B1

[0043]

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