Vehicle tyre and inner layer for vehicle tyres

Abstract

The invention relates to a vehicle tyre which contains, at least in an inner layer (1), a vulcanised material which is obtained by sulfur vulcanisation of a rubber mixture, which rubber mixture contains at least the following constituents: a) at least 80 phr of at least one isobutene-isoprene rubber (IIR), b) a total of 5 to 50 phr of carbon fillers comprising at least one carbon black, wherein the carbon black preferably has a low average BET surface area according to DIN ISO 9277 of at most 30 m2 / g.

Description

[0001] 202400937

[0002] - 1 -

[0003] Description

[0004] Vehicle tires and inner layer for vehicle tires

[0005] The invention relates to a vehicle tire, in particular a commercial vehicle tire. Furthermore, the invention relates to the inner layer of a tire or commercial vehicle tire and the use of the sulfur-curable rubber compound for the inner layer of a tire.

[0006] The rubber composition of the inner layer (also called the inner liner or inner wall) of the tire and the squeegee layer radially adjacent to the inner layer on the outside of the tire influences the driving characteristics of a vehicle tire, especially a pneumatic tire for commercial vehicles. Therefore, very high demands are placed on these rubber compounds, particularly with regard to tire rolling resistance.

[0007] The rolling resistance (RR) of tires is frequently measured using drum tests. Drum tests are generally the basis for legal rolling resistance certifications, the awarding of rolling resistance labels, or the verification of rolling resistance limit requirements. These drum tests are typically based on tests according to ISO 28580. ISO 28580 specifies a target ambient temperature of 25 °C for the rolling resistance test and also provides a linear rolling resistance correction formula for test temperatures between 20 °C and 30 °C.

[0008] Specifically for truck and / or bus tires, little has been published to date regarding the influence of low or very low ambient temperatures (e.g., below 0 °C) on tire rolling resistance. The available correction formula for the effect of ambient temperature on rolling resistance is only valid for a temperature range of 20 °C to 30 °C. Furthermore, this correction formula does not take into account individual tire characteristics and technologies, such as the rubber compounds used, the tire construction, the tire profile, etc.; it is based solely on the measured value.

[0009] - 2 -

[0010] Rolling resistance value with fixed input values ​​and only distinguishes between "passenger car tires", "smaller truck and bus tires" and "larger truck and bus tires".

[0011] The present invention was based on the objective of providing a rubber compound for an inner layer and a corresponding inner layer for tires which, compared to the prior art, exhibits an improvement in the tire's property profile, particularly with regard to rolling resistance behavior at low ambient temperatures below standard room temperature and the temperature sensitivity of the rolling resistance behavior.

[0012] Surprisingly, the rubber compound, vulcanizate and inner layer according to the invention improve the rolling resistance of the tire at low ambient temperatures.

[0013] 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 or elements of the tire, with varying 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 encompassed by the invention.

[0014] When specifying size ranges or value intervals in this text, the stated limit values ​​are always included within the specified range or interval.

[0015] The following section describes in more detail the components of the rubber compound according to the invention and the properties of the inner layer produced therefrom.

[0016] All information relating to the components of the rubber compound according to the invention, regardless of the degree of preference given to these features, applies in accordance with 202400937.

[0017] - 3 - also for the vulcanizate according to the invention, the tire layers according to the invention, the (commercial) vehicle tire according to the invention and uses according to the invention.

[0018] 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 is based on 100 parts by weight of the total mass of all rubbers present in the mixture with a molecular weight Mw according to GPC greater than 20,000 g / mol. The specified value ranges always include the limit values.

[0019] According to the invention, the rubber mixture contains at least one diene rubber.

[0020] 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.

[0021] At least one of the contained rubbers is preferably an isoprene-isobutylene copolymer (HR; also isobutene-isoprene rubber or butyl rubber for short).

[0022] The isoprene-isobutylene copolymer can preferably be halogenated, e.g., by reaction with chlorine gas to form chlorobutyl rubber (CI IR) or with liquid bromine to form bromobutyl rubber (BIIR). In summary, halogenated HR is generally also referred to as HHR. The different HHR types, such as CHR and BIIR, can be blended in any desired ratio.

[0023] Preferably, the rubber compound according to the invention contains at least 80 phr, more preferably at least 90 phr HR or CHR and / or BIIR.

[0024] According to the invention, the rubber mixture can further comprise at least one other diene rubber from the group consisting of natural polyisoprene (NR) and synthetic polyisoprene (IR), epoxidized polyisoprene (ENR), butadiene rubber (polybutadiene, BR), in particular poly-isobutadiene, styrene-butadiene rubber (SBR), 202400937

[0025] - 4 - in particular, solution-polymerized styrene-butadiene rubber (SSBR) or emulsion-polymerized styrene-butadiene rubber (ESBR). The proportion of the other diene rubber(s) is preferably a maximum of 20 phr, more preferably a maximum of 10 phr, more preferably a maximum of 5 phr, and more preferably at least 1 phr.

[0026] Other possible diene rubbers that may be present in smaller quantities in the mixture according to the invention are butadiene isoprene rubber, styrene isoprene rubber, polynorbornene, ethylene propylene diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluorocarbon rubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene isoprene butadiene terpolymer, hydrogenated acrylonitrile butadiene rubber and hydrogenated styrene butadiene rubber.

[0027] In this process, plasticizers, vulcanization systems and additives known to experts for these rubbers are used preferentially.

[0028] With the proportions of HR or BIIR and / or CI IR according to the invention, the problem underlying the invention is solved particularly well, and a tire with an inner layer made from the rubber compound exhibits good rolling resistance behavior and low temperature sensitivity of the rolling resistance behavior, especially at low temperatures.

[0029] Preferably, the rubber compound contains only HR as a rubber component. Preferably, the proportions of HR, in particular CHR and BIIR, add up to approximately 100 phr or exactly 100 phr, more preferably 100.00 phr. Preferably, only CHR or only BIIR is present.

[0030] In the event that the rubber mixture contains less than 100 phr of HR, at least one further rubber, preferably at least one further diene rubber selected from the above list, is included, such that the sum of the contained rubbers by definition equals 100 phr.

[0031] The rubber polymers used, in particular the HR used, can be end-group modified with modifications and functionalizations if necessary. 202400937

[0032] - 5 - and / or be functionalized along the polymer chains. The polymers can be simply or arbitrarily multiply modified. The modifications can involve 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 groups and / or silane sulfide groups. Other modifications, also known as functionalizations, are also possible and are known to a competent person. Metal atoms can be part of such functionalizations.

[0033] The HR, and in particular HIIR, rubber used in the present rubber compound may optionally be specifically functionalized for interaction with soot, especially carbon black (industrial soot).

[0034] It is also possible to use butyl ionomer, an HR or HHR modified with ionic groups, such as the product offered by Lanxess under the name “X_Butyl I4565P”, or a comparable product.

[0035] According to one embodiment, the halogenated isobutene-isoprene rubber (HHR) consists of a maximum of 50%, preferably 10% to 40%, and particularly preferably 10% to 30% of a modified butyl ionomer, which is preferably advantageously suitable for forming reversible connection points by ionic groups in the pre-vulcanized state.

[0036] The combination enables an unexpectedly significant performance advantage of the rubber compound. If an inner layer of a tire contains the rubber compound according to the invention, an unexpectedly significant improvement in the tire's rolling resistance behavior at low temperatures is observed.

[0037] The HR and / or HHR used may be wholly or partially a material obtained, for example, through the recycling of hoses or other rubber articles made from HR and / or HHR, and is also known to those skilled in the art as "regenerate" or "reclaimed material". 202400937

[0038] - 6 -

[0039] According to the invention, the rubber compound further comprises 5 to 50 phr, preferably 10 to 45 phr, particularly preferably 20 to 40 phr, more preferably 30 to 40 phr of carbon fillers, preferably carbon black. The carbon fillers comprise at least one or more types of carbon black, in particular carbon black from renewable resources or recycled carbon black, graphite, expandable graphite, natural graphite, or ground coal.

[0040] Other potentially reinforcing carbon-based 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), graphene and so-called “carbon-silica dual-phase fillers”.

[0041] The carbon blacks according to the invention preferably have a low mean nitrogen surface area (BET surface area) according to DIN ISO 9277 of a maximum of 30 m2 / g, preferably a maximum of 25 m2 / g, particularly preferably a maximum of 20 m2 / g, even more preferably a maximum of 15 m2 / g or a maximum of 12 m2 / g, such as carbon black N990.

[0042] The filler used (e.g., carbon black or other fillers) can consist partially or entirely of recycled, renewable, and / or bio-based material, such as recovered or recycled filler or filler based on sustainable or renewable raw materials, e.g., silica derived from rice husks or carbon black derived from vegetable oils such as palm oil, rapeseed oil, etc. The carbon black is preferably recycled. For example, it can also be carbon black generated by the pyrolysis of used tires or rubber.

[0043] Furthermore, optionally up to 100 phr, preferably up to 50 phr, more preferably up to 25 phr, additional fillers may be included. Within the scope of the present invention, these include in particular silicic acid (silica), rice husk silica obtained from rice hulls, kaolin, talc, and chalk.

[0044] The other fillers may in particular also contain a dry mixture compound according to DE 10 2009 026 229 A1, which contains at least 25% of at least one 202400937

[0045] - 7 - contains delaminated aluminohydrosilicate modification, wherein the delaminated aluminohydrosilicate modification has a two-layer lattice.

[0046] The percentage refers to the total weight of the dry mixture compound. The two-layer lattice of the delaminated aluminohydrosilicate modification is preferably a dioctahedral two-layer lattice.

[0047] In a particularly preferred embodiment, the dry mixture compound additionally contains at least 40% of a di- or trioctahedral three-layer silicate from the group of phyllosilicates and / or at least 10% of a crystalline quartz modification or amorphous quartz. The percentage refers to the total weight of the dry mixture compound.

[0048] Furthermore, the rubber compound preferably contains zinc oxide (ZnO) as an activator. This can be any type of zinc oxide known to those skilled in the art, such as ZnO granules or powder. The zinc oxide used conventionally usually 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.

[0049] The ratio of zinc oxide to sulfur (see vulcanization system below) in the rubber mixture is preferably between 1:1 and 15:1, more preferably between 1:1 and 10:1, and particularly preferably between 1.5:1 and 10:1.

[0050] The total amount of zinc oxide and sulfur in the rubber mixture is preferably between 2 and 5 phr, more preferably between 2.5 and 4.5 phr and particularly preferably between 2.5 and 3.5 phr.

[0051] 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:

[0052] 1) Anti-aging agents and ozone-protective waxes such as 202400937

[0053] - 8 - e.g. diamines, such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-ditolyl-p-phenylenediamine (DTPD), N-(1,4-dimethylpentyl)-N'-phenyl-p-phenylenediamine (7PPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), and / or dihydroquinolines, such as 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), and / or substituted bisphenols, such as 2,2'-methylenebis(4-methyl-6-tert-butylphenol) (BPH), and / or substituted phenols, such as butylhydroxytoluene (BHT),

[0054] 2) other activators, such as fatty acids, e.g. stearic acid, or zinc complexes such as zinc ethylhexanoate,

[0055] 3) further activators and / or agents for the binding of fillers, in particular carbon black or silica, such as organosilicon compounds (silanes, binding to silica), S-(3-aminopropyl)-thiosulfuric acid and / or their metal salts (binding to carbon black).

[0056] 4) Hydrocarbon resins, in particular phenolic resins, especially as adhesive resins,

[0057] 5) Mastication aids, such as 2,2'-dibenzamidodiphenyldisulfide (DBD) and

[0058] 6) Process aids, in particular fatty acid esters and metal soaps, such as zinc soaps and / or calcium soaps; 1) 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 rapeseed oil, or Faktisse or hydrocarbon resins or liquid polymers, the average molecular weight of which 202400937

[0059] - 9 -

[0060] (Determination by GPC = gel permeation chromatography, based on BS ISO 11344:2004) between 500 and 20000 g / mol.

[0061] 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.

[0062] The quantity of other additives in the total quantity is preferably 0 to 100 phr, particularly preferably 0 to 50 phr, and most preferably 0 to 10 phr.

[0063] The rubber compound according to the invention is preferably used in vulcanized form, particularly in inner layers of vehicle tires.

[0064] The terms “vulcanized” and “crosslinked” are used synonymously within the scope of the present invention.

[0065] 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. Preferably, at least one sulfenamide accelerator is 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), N-tert-butyl-2-benzothiazole sulfenimide (TBSI), and / or at least one guanidine accelerator, such as diphenylguanidine (DPG).

[0066] In particular, two or more accelerators can also be used. 202400937

[0067] - 10 -

[0068] Any sulfur-donating substance known to experts can be used as the sulfur-donating substance.

[0069] Furthermore, one or more reversion protectants, such as 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane, hexamethylene-1,6-bis(thiosulfate) disodium salt dihydrate, and / or tetrabenzylthiuram disulfide (TBzTD), may be used in the rubber compound.

[0070] Furthermore, vulcanization retarders may be present in the rubber compound.

[0071] The rubber compound is otherwise produced according to the standard procedure 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 the mixing stages, preferably in the final stage.

[0072] The finished compound is further processed, for example by extrusion or calendering, and formed into the appropriate shape. The rubber compound according to the invention is particularly suitable for use as an inner layer in vehicle tires, especially pneumatic tires.

[0073] For use as an inner layer, the mixture is prepared as a ready-made mixture and shaped accordingly before vulcanization, and then applied and vulcanized as usual during the production of the vehicle tire blank.

[0074] The subject matter of the present invention, as already explained at the outset, is in particular a vehicle tire and an inner layer in the vehicle tire, which comprises at least one vulcanizate made from the vulcanized rubber compound according to the invention.

[0075] Within the scope of the present invention, vehicle tires are defined as pneumatic vehicle tires, including tires for industrial and construction vehicles, trucks, 202400937

[0076] - 11 -

[0077] This applies to passenger car and motorcycle tires. It is primarily intended for use with commercial vehicle tires such as truck or bus tires.

[0078] The vehicle tire according to the invention is preferably of radial design and preferably provided with a tread, a belt assembly comprising several belt layers, the inner layer, which is preferably facing the inside of the tire and is airtight, a carcass insert with carcass cords extending in a radial direction or substantially in a radial direction and a squeegee layer located between the carcass insert and the inner layer, which is based on a rubber compound.

[0079] Particularly preferably, the vehicle tires within the scope of the present invention have a squeegee layer.

[0080] The squeegee layer is usually located between the airtight inner layer and a rubber lining of a carcass insert in the vehicle tire. A squeegee layer for optimizing tire rolling resistance is described, for example, in DE102018 213 704 A1 or in EP 3611036 B1.

[0081] The squeegee ply is often made from a rubber compound similar to the rubber compound of the carcass ply; in particular, both compounds typically meet the requirements for steel cord adhesion and durability. It is therefore common practice to use natural rubber, or a high proportion thereof, in the rubber compound for the squeegee ply, along with an appropriate adhesion promoter system. Typical squeegee compounds also contain a high proportion of reinforcing fillers, usually carbon black, in amounts exceeding 50 phr. Due to their compound composition, known squeegee plies exhibit good mechanical tensile strength and low flow or creep.

[0082] It is known that the squeegee layers in commercial vehicle tires contribute to their rolling resistance. However, they cannot be omitted without negatively impacting the tires' durability and retreadability. 202400937

[0083] - 12 -

[0084] The squeegee layer of the tire according to the invention is preferably based on a rubber compound whose filler content of carbon black (always including carbon black) and / or silica is 20 phr to less than 43 phr in order to reduce rolling resistance without impairing the durability or retreadability of the tires.

[0085] A corresponding squeegee position, improved with regard to rolling resistance, was first described in the aforementioned publications EP 3611036 B1 and DE102018 213 704 A1.

[0086] Preferably, the filler content in the rubber mixture of the squeegee layer is less than 40 phr, preferably even less than 35 phr, particularly preferably 20 phr to less than 35 phr.

[0087] The invention will now be explained in more detail using comparative and exemplary embodiments.

[0088] The example according to the invention is designated E1 and the comparison example is designated V1.

[0089] Substances used:

[0090] - halogenated HR (HIIR, e.g. BIIR or CIIR)

[0091] - Soot:

[0092] N772 with BET surface area according to DIN ISO 9277 of 30 m2 / g, N990 with BET surface area according to DIN ISO 9277 of 10 m2 / g,

[0093] - Kaolin,

[0094] - Zinc oxide,

[0095] - Sulfur,

[0096] - Other ingredients: plasticizers, resins, processing aids, stearic acid, magnesium oxide, other vulcanizing chemicals.

[0097] The mass fractions in phr are given in Table 1. 202400937

[0098] - 13 -

[0099] Table 1:

[0100] The mixture was produced according to the two-stage process commonly used in the rubber industry for inner liners.

[0101] Test specimens were produced from all mixtures by vulcanization to t95 to t100 (measured on the Moving Die Rheometer according to ASTM D 5289-12 / ISO 6502) under pressure at 150 °C and material properties typical for the rubber industry were determined with these test specimens using the test procedures specified below.

[0102] • Shore A hardness at room temperature (RT) and at 70 °C according to ISO 868,

[0103] • Rebound at room temperature (RT) and at 70 °C according to ISO 4662. Rebound, also known as rebound elasticity, is an indicator of the rolling resistance behavior of the sidewall compound. High rebound elasticity indicates low, and therefore good, rolling resistance for the sidewall compound used.

[0104] • Stress value at 300% elongation (= modulus 300) at RT, tensile strength and elongation at break at room temperature (RT), according to DIN 53 504.

[0105] Table 2: 202400937

[0106] - 14 -

[0107] As can be seen from Tables 1 and 2, the use of a carbon black with a lower BET surface area (N990, E1, see Table 1) leads to a significant increase in the rebound values ​​both at RT and at an elevated temperature of 70 °C compared to the use of a carbon black with a higher BET surface area (N772, V1, see Table 1) (see comparison V1 vs. E1).

[0108] Test simulations were performed for tires with the compounds listed in Table 1 as the inner layer to compare rolling resistance behavior and its changes at different temperatures. Simulation results are shown below.

[0109] The tire considered in these simulations has the following characteristics: The test tire is a 315 / 70 R 22.5" drive axle tire, optimized for long haul applications, with a focus on optimizing rolling resistance: The tire has a low-groove tread pattern with sipes (13.3% groove volume, see e.g. definition of groove volume in EP 2 292 448 B1) and a low tread depth (13.2 mm in the example).

[0110] As described in EP 2 292 448 B1, the treads of pneumatic tires for commercial vehicles have circumferential grooves which divide the tread into circumferential ribs, wherein an envelope running parallel to the tread periphery in the tread, which touches the deepest circumferential groove from the radial inside, together with the tread periphery and shoulder-side flank sections defines a tread gross volume and all grooves in the tread define the groove volume.

[0111] It should be noted that in real-world tire use, the actual ambient temperatures differ considerably from the target temperature of the test of 202400937.

[0112] - 15 -

[0113] Rolling resistance behavior in the so-called drum test according to ISO 28580 may deviate from 25 °C.

[0114] Significant differences in ambient temperature have a considerable impact on the rolling resistance of the tire. Generally, a lower ambient temperature results in higher, and therefore worse, rolling resistance compared to the rolling resistance measured under ISO test conditions. Conversely, a higher ambient temperature generally results in lower, and therefore better, rolling resistance compared to the rolling resistance measured under ISO test conditions.

[0115] The rolling resistance of a tire directly affects its energy absorption or consumption, which increases at lower temperatures. This also affects, for example, the fuel consumption of combustion engine vehicles or the electricity consumption of battery-powered electric vehicles.

[0116] In battery-powered vehicles, the increase in tire-related energy consumption at low ambient temperatures, i.e., operating temperatures, therefore also has a negative impact on the maximum range with a certain, e.g., maximum, battery charge, compared to the maximum range at higher ambient temperatures.

[0117] While ISO 28580 provides an extrapolation function for ambient temperatures between 20 °C and 30 °C, this function cannot be used for very low ambient temperatures below 20 °C, especially below 0 °C.

[0118] Since rolling resistance results for low ambient temperatures (below 20 °C, especially below 0 °C) are not known or published, particularly for commercial vehicle tires such as truck / bus tires, a quantified correlation of tire rolling resistance at low ambient temperatures is not available.

[0119] For this reason, no optimization possibilities are known that would reduce the sensitivity of tire rolling resistance to low ambient temperatures.

[0120] - 16 - reduced. Consequently, no measures are known that reduce the increase in tire energy consumption at low ambient temperatures (below 20°C, especially below 0°C) compared to higher ambient temperatures (20°C to 30°C). This means, for example, that for battery-powered electric vehicles, no tire-related optimization measures are known that reduce the difference between the maximum range for a given battery charge (e.g., maximum) at low ambient temperatures and the maximum range for a given battery charge (e.g., maximum) at higher ambient temperatures.

[0121] In order to quantify the change in rolling resistance behavior at low temperatures, a simulation methodology was therefore developed in two steps within the scope of the present invention.

[0122] In the first step, the tire rolling resistance was measured in a drum test at various ambient temperatures. Apart from the ambient temperatures, the test conditions were the same as in the test according to ISO 28580. In particular, the warm-up time in the drum tests also corresponded to the ISO standard.

[0123] The second step was a simulation of the tire rolling resistance using the same parameters as in the drum tests.

[0124] To validate the simulation methodology, three different tire variants, described below, were tested in drum tests at different temperatures, and the same tests were replicated by simulations. The results for rolling resistance in the tests and in the simulations are shown in Table 3.

[0125] Tire option 1:

[0126] A drive axle tire with dimensions 315 / 70 R 22.5", optimized for long-haul transport, with a focus on minimizing rolling resistance: The tire has a low groove volume with sipes (13.3% groove volume, determined according to EP 2 292 448) and a shallow tread depth (13.2 mm). The tread and carcass of the tire comprise vulcanized rubber compounds optimized for low rolling resistance under ISO drum test conditions. The tire contour is also optimized with regard to 202400937.

[0127] - 17 -

[0128] Rolling resistance optimized. Tire variant 1 was also used as the basis for the simulations carried out in relation to the present invention.

[0129] Tire variant 2:

[0130] A drive axle tire with dimensions 315 / 70 R 22.5", optimized for regional use, with a focus on optimizing mileage and traction: The tire has a high groove profile with blocky elements (16.2% groove volume, groove volume determined according to EP 2 292 448) and a high tread depth (18.7 mm). The tire's tread compound is vulcanized and optimized for high mileage and traction. The tire carcass is also vulcanized and optimized for consistently high mileage.

[0131] Tire variant 3: Essentially the same tire as in tire variant 2, but with a tread depth ground down to 4 mm. This grinding process is carried out with considerable effort to achieve a very smooth tire surface, closely resembling the surface quality of a tire at the end of its service life.

[0132] The three tire variants described cover a wide range of tire design limits:

[0133] - wide range of tire rolling resistances,

[0134] - wide range of profile depths,

[0135] - Tread depths of new tires and tires that are almost completely worn out

[0136] - wide range of tread characteristics.

[0137] The rolling resistance of the three described tire variants was tested and simulated at the following three different ambient temperatures: +25 °C (reference temperature according to ISO 28580),

[0138] +9 °C (temperature close to the annual average temperature for Central European countries),

[0139] -10°C 202400937

[0140] - 18 -

[0141] The rolling resistance simulations in the second step were performed for exactly the same tire variants and for the temperatures used in the tire tests:

[0142] The rolling resistance simulations were performed using a specially developed and optimized rolling resistance simulation program.

[0143] The same boundary conditions were used for the rolling resistance simulation as for the tire test (e.g., drum diameter, speed, air pressure, tire load, rim size).

[0144] Table 3 shows the rolling resistance results of the drum tests and simulations described above in % relative to the reference value at 25 °C (100 %).

[0145] Table 3:

[0146] Table 3 shows that the simulation results and the test results are very similar.

[0147] Table 3 also shows that the rolling resistance for all tested tire types increases significantly with decreasing temperature.

[0148] The following simulations were performed for tires with the compounds according to Table 1 as the inner layer compound, each containing a squeegee layer.

[0149] The tires contained either a standard squeegee layer or an improved squeegee layer in accordance with DE 102018 213 704 A1 (publication D1).

[0150] Apart from the inner layer compound used and the optionally used improved squeegee layer compound, the tires corresponded to the above 202400937

[0151] - 19 - described tire variant 1, to compare the rolling resistance behavior and its change at different temperatures.

[0152] For simulations A to D, the following property combinations were assumed according to Table 4.

[0153] Table 4:

[0154] The standard squeegee layer and the squeegee layer according to D1 differ primarily in the rubber compound used.

[0155] Mixing ratios differ, in particular, according to Table 5.

[0156] Table 5: The simulation results for rolling resistance at room temperature (RT = 25 °C) are given in Table 6 as absolute values ​​in kg / t. The temperature sensitivity is also given as the change in rolling resistance at -10 °C compared to the rolling resistance at 25 °C. 202400937

[0157] - 20 -

[0158] In addition, the rolling resistance sensitivity, i.e. the change in rolling resistance at -10 °C compared to rolling resistance at 25 °C room temperature, is also given in %.

[0159] Table 6:

[0160] All tires B, C, and D each show an improvement in rolling resistance at 25 °C compared to the reference tire A. Both the use of the inventive inner layer compound and the improved squeegee layer contribute to the reduction in rolling resistance at room temperature.

[0161] All tires B, C, and D also show an improvement in rolling resistance at -10 °C compared to the reference tire A. Both the use of the inventive inner layer compound and the improved squeegee layer contribute to the reduction in rolling resistance.

[0162] Inventive tires with inner layers containing or formed from the vulcanizate according to the invention (A and C) surprisingly exhibit a 202400937

[0163] - 21 - significantly improved rolling resistance behavior both at RT and at low temperatures (shown here at -10 °C: B vs. A and D vs. C).

[0164] In addition to the absolute rolling resistance values ​​in kg / t and their dependence on the compounds used, the percentage temperature sensitivity, i.e., the percentage increase in rolling resistance depending on the ambient temperature, also plays an important role. High temperature sensitivity of the rolling resistance means a large difference in rolling resistance and thus in tire-related energy consumption at different ambient temperatures. To enable a small difference in tire-related energy consumption at different ambient temperatures, the temperature sensitivity of the tire rolling resistance should be as low as possible.

[0165] Surprisingly, tires according to the invention with inner layers containing or formed from the vulcanizate according to the invention (B and D) also exhibit a significantly improved, i.e. lower, temperature sensitivity of the rolling resistance behavior (when comparing -10 °C vs. RT) (shown here at -10 °C: B vs. A and D vs. C).

[0166] Tire B shows an improvement (decrease) of 0.82% in temperature sensitivity compared to tire A. Surprisingly, tire D even shows an improvement of 1.99% in temperature sensitivity compared to tire C. However, tire C with squeegee according to D1 shows a significant deterioration (increase) of 1.1% in temperature sensitivity compared to tire A.

[0167] The optimized inner layer compound thus improves temperature sensitivity by 0.82% when using the standard squeegee compound (tire B compared to tire A).

[0168] Through a combination of the optimized inner layer compound and the squeegee compound, the temperature sensitivity surprisingly improves by 0.89% compared to the standard tire A (see tire D vs. tire A). Surprisingly, this results in a positive synergy regarding rolling resistance for the combination in tire D. This was particularly unexpected, as the use of the squeegee layer according to D1 in combination 202400937

[0169] - 22 - with a standard inner layer (with the mixture according to V1) leads to a significant deterioration in temperature sensitivity (see C).

[0170] This improves the properties of the tire or the inner layer through the features of the invention.

[0171] Figure 1 shows an exemplary tire in cross-section (only the half to the right of the tire zenith Z is fully shown; the tire is built in a mirror-symmetrical manner with respect to Z).

[0172] Fig. 1 shows the usual components of a commercial vehicle tire in radial construction in an order from the inside of the tire to the outside, in particular an airtight inner layer 1 containing the rubber compound according to the invention, a radial carcass 2 reinforced with strengthening elements, a squeegee layer 3 according to the invention between the airtight inner layer 1 and the radial carcass 2 and a sidewall 4.

[0173] Furthermore, a running strip 5 and radially within the running strip 5 a belt bandage 6 with belt layers is shown.

[0174] The sidewall 4 extends laterally along the tire from the tread 5 to a bead area 7 of the tire.

[0175] The tread 5 can be constructed in two layers in the radial direction, for example, and consist of a tread cap with circumferential grooves and ribs that form the profile, and a tread base extending radially within the tread cap. 202400937

[0176] - 23 -

[0177] Reference symbol list

[0178] 1 Inner layer 2 Radial carcass

[0179] 3 Squeegee layer

[0180] 4 side wall

[0181] 5 treads

[0182] 6 Belt bandage 7 Bulge area

[0183] Z Tire zenith

Claims

202400937 - 24 - Patent claims 1. A vehicle tire comprising at least in an inner layer (1) a vulcanizate obtained by sulfur vulcanization of a rubber compound containing at least the following components: a) at least 80 phr, preferably at least 90 phr, particularly preferably at least 95 phr of at least one isobutene-isoprene rubber (HR) and / or halogenated isobutene-isoprene rubber (HIIR), b) a total of 5 to 50 phr, preferably 10 to 45 phr, particularly preferably 20 to 40 phr of carbon fillers, comprising at least one carbon black, wherein the carbon black preferably has a low mean BET surface area according to DIN ISO 9277 of a maximum of 30 m² / g, preferably of a maximum of 25 m² / g, more preferably of a maximum of 20 m² / g, even more preferably of a maximum of 15 m² / g, and most preferably of a maximum of 12 m² / g.

2. Vehicle tires according to claim 1, wherein the carbon fillers comprise one or more of carbon black, in particular carbon black from renewable resources and / or recycled carbon black, graphite, expandable graphite, natural graphite or ground coal.

3. Vehicle tires according to claim 1 or 2 with the following further components in the rubber compound: c) 0 to 100 phr, preferably 0 to 50 phr, particularly preferably 0 to 25 phr, most preferably 0 to 10 phr additional fillers, preferably comprising one or more of silica, rice husk silica, talc, kaolin or a dry mixture compound containing at least 25% of at least one delaminated aluminohydrosilicate modification, wherein the delaminated aluminohydrosilicate modification has a two-layer lattice.

4. Vehicle tires according to any one of claims 1 to 3 with the following further components in the rubber compound: d) 2.5 to 5 phr, preferably 2.5 to 4.5 phr, more preferably 2.5 to 3.5 phr in total zinc oxide (ZnO) and sulfur, wherein the ratio of zinc oxide to sulfur in the 202400937 - 25 - The rubber mixture preferably has a ratio between 1:1 and 15:1, more preferably between 1:1 and 10:1, and particularly preferably between 1.5:1 and 10:

1.

5. Vehicle tires according to any one of claims 1 to 4, wherein the isobutene-isoprene rubber (HR) is a halogenated isobutene-isoprene rubber (HIIR), in particular either a bromobutyl (BI IR) or a chlorobutyl (CI IR) rubber.

6. Vehicle tire according to any one of claims 1 to 5, wherein the halogenated isobutene-isoprene rubber (HIIR) consists of a modified butyl ionomer to a maximum of 50%, preferably 10% to 40%, and particularly preferably 10% to 30%, which is suitable for forming reversible connection points by ionic groups in the pre-vulcanized state.

7. Vehicle tire according to claim 6, wherein the functionalization is located at the end of the polymer chain or at other positions of the polymer chain, wherein the functionalization is one comprising 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 groups and / or silane sulfide groups.

8. Vehicle tire according to any one of claims 1 to 7 comprising the following further component in the rubber compound: e) 1 to 20 phr, preferably 1 to 10 phr, more preferably 1 to 5 phr of at least one further diene rubber from the group consisting of natural polyisoprene (NR) and synthetic polyisoprene (IR), epoxidized polyisoprene, butadiene rubber (polybutadiene, BR), in particular polyisobutadiene, styrene-butadiene rubber (SBR), in particular solution-polymerized styrene-butadiene rubber (SSBR) or emulsion-polymerized styrene-butadiene rubber (ESBR).

9. Vehicle tires according to any one of claims 1 to 8, wherein the raw materials used in the rubber compound are partially or completely based on recycled, renewable and / or bio-based raw materials, wherein preferably all rubber materials used in the rubber compound are based on recycled, 202400937 - 26 - based on renewable and / or bio-based raw materials, in particular on IIR recycled rubber or on recycled natural rubber.

10. Vehicle tires according to any one of claims 1 to 9, wherein the filler(s) used in the rubber compound consist partly or entirely of recycled, renewable and / or bio-based material, wherein in particular carbon blacks from recycled carbon black and / or silica based on rice husks are used.

11. Vehicle tire according to any one of claims 1 to 10, wherein the vehicle tire has a radially outer squeegee layer (3) adjoining the inner layer, comprising a vulcanized rubber compound, the filler content of which is carbon black and / or silica 20 to less than 43 phr, preferably 20 to 40 phr, more preferably 20 to 35 phr.

12. Vehicle tires according to any one of claims 1 to 11, wherein the rubber compound contains oils, e.g. plasticizing oils, wherein the oils used are at least partially rapeseed oil.

13. Vehicle tire according to one of claims 1 to 12, wherein the tire is a new tire or a hot-retreaded tire which is a pneumatic tire.

14. Vehicle tire according to any one of claims 1 to 13, which is a commercial vehicle tire.

Images