Vehicle pneumatic tires

Abstract

Vehicle pneumatic tire with a tread having a cap (1) / base (2) structure, wherein the cap (1) contains the tread profile and the base (2) consists of two different rubber compounds A and B, characterized in that three or more layers (2a, 2b) of the rubber compounds A and B are arranged radially above one another, wherein the layers (2a, 2b) of the rubber compounds A and B are arranged alternately radially above one another and wherein the rubber compound A has a rebound elasticity at 70 °C according to DIN 53512 of 62% to 85% and the rubber compound B has a rebound elasticity at 70 °C according to DIN 53512 of 30% to 60%.

Description

[0001] The invention relates to a pneumatic vehicle tire with a tread having a cap / base structure, wherein the cap contains the profile of the tread and the base consists of two different rubber mixtures A and B.

[0002] It is well known that pneumatic vehicle tires, in order to optimize the conflicting objectives of rolling resistance versus abrasion behavior, have a two-part tread consisting of a radially outer part, which comes into contact with the road surface, and a radially inner part. In the technical world, the radially outer part is referred to as the "cap" and the radially inner part of the tread as the "base."

[0003] While the rubber compound of the cap is designed to minimize material loss upon contact with the road surface, the rubber compound of the base is typically designed to minimize heat buildup. One known way to reduce heat buildup in a rubber compound is to reduce the filler content by adding fillers such as carbon black and / or silica.

[0004] However, it is known that very soft rubber compounds in the base are more susceptible to cracking, for example, due to stones penetrating the base during driving. Tearing of the base can subsequently lead to further foreign objects entering the tire and thus damaging internal components, which can lead to, among other things, corrosion of the tire's steel reinforcements.

[0005] Furthermore, cracks in the tread base of pneumatic vehicle tires, also known as "groove cracks" in the technical world, can extend to the base. Here, too, a base that is as crack-resistant as possible is advantageous to prevent further damage and tire failures, such as shoulder tears.

[0006] In the base compound of pneumatic vehicle tires, there is therefore a trade-off between rolling resistance and tear resistance. The abrasion properties of the base compound, especially in the area of ​​the belt edges, are also relevant to the durability of pneumatic vehicle tires.

[0007] In addition, the base of a pneumatic vehicle tire influences its handling characteristics. A low-filler and therefore usually relatively soft rubber compound in the base leads to poor handling.

[0008] A pneumatic vehicle tire of the type mentioned above is known, for example, from DE 198 50 766 A1. According to one embodiment, the pneumatic vehicle tire has a tread with a cap containing the tread pattern and a base consisting of a central part made of a first rubber material and two shoulder-side parts made of a second rubber material. The second rubber material is harder than the first rubber material and differs from the first rubber material in its hysteresis properties. As a result, the pneumatic vehicle tire has low rolling resistance.

[0009] DE 10 2004 036 517 A1 discloses a pneumatic vehicle tire with a tread comprising an upper tread section and a lower tread section. The rubber material of the lower tread section has a lower loss factor than the rubber material of the upper tread section. In the two lateral areas adjacent to the tire shoulders, a tread center section made of a rubber material with a higher thermal conductivity than the rubber material of the upper tread section is provided between the upper tread section and the lower tread section. The pneumatic vehicle tire is intended to exhibit high mileage and good belt durability.

[0010] DE 10 2011 001 877 A1 discloses a pneumatic vehicle tire with a tread consisting of a cap and a base. An electrically conductive, wedge-shaped rubber component penetrates both the cap and the base in one of the tire shoulders and forms a lateral part of the base. Such a pneumatic vehicle tire is intended to have low rolling resistance.

[0011] JP 2001 206 012 A discloses a commercial vehicle tire with a tread comprising a cap containing the tread pattern and a single-layer base. In one embodiment, the cap is composed of three layers in the radial direction, with the rubber materials of the layers differing in terms of modulus and loss factor. The cap is intended to be slightly deformed (compressed) during rolling, which should subsequently reduce the hysteresis loss of the tread and improve the tire's rolling resistance.

[0012] JP 2009 255 747 A discloses another pneumatic vehicle tire with a tread comprising a radially multi-layered cap and a single-layer base. The rubber materials of the cap layers have different moduli of elasticity, with a layer of a first rubber material with a higher modulus of elasticity following a layer of a second rubber material with a lower modulus of elasticity. Such a cap should be subject to little deformation (compression) as the tire rolls, thereby maintaining a large contact area between the tread and the ground. Furthermore, the tire should exhibit good grip properties.

[0013] It is known in the prior art to address some of these conflicting objectives in the base of pneumatic vehicle tires by means of a construction in which the base has different areas made of different rubber compounds.

[0014] For example, DE 10 2006 012 536 A1, US 2012 / 0285590 A1, and WO 2012 / 119844 A1 describe a pneumatic vehicle tire with a cap / base construction, in which the base consists of different sections in the axial direction, with the base having a different rubber compound in the lateral shoulder areas than in the central area arranged above the belt. What these documents have in common is that the aforementioned construction is intended to reduce heat buildup and improve rolling resistance. At the same time, the belt durability and / or handling behavior are intended to be improved or not impaired.

[0015] The conflict between heat build-up, and thus rolling resistance behavior, and tear properties with regard to the challenges mentioned above is not considered in the aforementioned documents.

[0016] The present invention is therefore based on the object of providing a pneumatic vehicle tire with a cap / base structure, wherein the base consists of two different rubber mixtures A and B, in which the base is at a higher level with regard to the conflicting objectives of rolling resistance vs. tear properties, without the pneumatic vehicle tire showing disadvantages in the other tire properties, such as abrasion and / or handling behavior.

[0017] This object is achieved according to the invention in that three or more layers of the rubber mixtures A and B are arranged radially one above the other, wherein the layers of the rubber mixtures A and B are arranged alternately radially one above the other and wherein the rubber mixture A has a rebound resilience at 70 °C according to DIN 53512 of 62% to 85% and the rubber mixture B has a rebound resilience at 70 °C according to DIN 53512 of 30% to 60%.

[0018] By the inventive combination of two different rubber mixtures A and B, which are arranged radially one above the other in three or more layers, the conflict of objectives between rolling resistance behavior and tear properties in the base is surprisingly resolved at a higher level.

[0019] For the purposes of the present application, “different rubber mixtures A and B” means that rubber mixture A has a different composition with regard to its components than rubber mixture B.

[0020] In the context of the present application, as described above, the "base" refers to the portion of the tread of pneumatic vehicle tires with a cap / base structure that does not come into contact with the road surface. The pneumatic vehicle tire according to the invention may also include a sub-plate known in the prior art between the radially outer belt ply and the base.

[0021] This resolves the conflicting objectives of rolling resistance and tear resistance at a higher level, while simultaneously simplifying the production of the pneumatic tire. This ease of manufacture results from the fact that superimposed layers can be extruded together.

[0022] The rubber compound A is optimized with regard to rolling resistance behavior and thus enables low heat build-up in the base of pneumatic vehicle tires.

[0023] The rubber compound B has good tear properties, so that the base has improved crack resistance.

[0024] The alternating arrangement of the rubber compounds A and B results in a uniform improvement in the tear properties across the entire thickness of the base and thus across the entire component base without significantly increasing the heat build-up in the base locally.

[0025] According to an advantageous development of the invention, the rubber mixture A contains 10 phr to 45 phr filler(s).

[0026] The rubber compound A preferably has a loss modulus E'' at 60 °C of 0.3 to 0.5 MPa and a tangent delta (tan δ or tan d) at 60 °C of 0.070 to 0.100. The loss modulus E" is determined according to DIN 53513 and 53535 by means of a temperature sweep (T-sweep). The determination of the tan δ is carried out according to DIN 53513 and 53535 by means of a temperature sweep (T-sweep).

[0027] It is also advantageous if the rubber compound B contains 46 phr to 100 phr filler(s).

[0028] The rubber compound B preferably has a loss modulus E'' at 60 °C of 0.53 to 1.0 MPa and a tangent delta (tan δ) at 60 °C of 0.120 to 0.160. The loss modulus E'' is determined according to DIN 53513 and 53535 using a temperature sweep (T-sweep). The determination of the tan δ is carried out according to DIN 53513 and 53535 using a temperature sweep (T-sweep).

[0029] For the purposes of the present invention, fillers are understood to mean silica, carbon black, and other fillers known to those skilled in the art. Other fillers include, in particular, aluminosilicates, chalk, starch, magnesium oxide, titanium dioxide, or rubber gels.

[0030] Preferably, rubber mixtures A and B each contain at least one diene rubber. Diene rubbers are rubbers produced by polymerization or copolymerization of dienes and / or cycloalkenes and thus contain C=C double bonds either in the main chain or in the side groups.

[0031] The diene rubber is selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or epoxidized polyisoprene and / or butadiene rubber and / or solution-polymerized styrene-butadiene rubber and / or emulsion-polymerized styrene-butadiene rubber and / or halobutyl rubber and / or polynorbornene and / or isoprene-isobutylene copolymer and / or ethylene-propylene-diene rubber and / or nitrile rubber and / or acrylate rubber and / or fluorine rubber and / or chloroprene rubber and / or silicone rubber and / or polysulfide rubber and / or epichlorohydrin rubber and / or styrene-isoprene-butadiene terpolymer and / or hydrogenated Acrylonitrile butadiene rubber and / or isoprene butadiene copolymer and / or hydrogenated styrene butadiene rubber and / or liquid rubbers.

[0032] The rubber mixture A of the pneumatic vehicle tire according to the invention preferably contains 80 to 100 phr of at least one natural and / or synthetic polyisoprene and 0 to 20 phr of at least one butadiene rubber and / or styrene-butadiene rubber. Particularly preferably, the rubber mixture A contains 100 phr of at least one natural and / or synthetic polyisoprene. This results in good rolling resistance indicators, such as rebound resilience at 70°C, with good tear properties.

[0033] The rubber mixture B of the pneumatic vehicle tire according to the invention preferably contains 30 to 100 phr, more preferably 60 to 100 phr, very preferably 80 to 100 phr, and again very preferably 80 to 90 phr, of at least one natural and / or synthetic polyisoprene and 0 to 70 phr, more preferably 0 to 40 phr, very preferably 0 to 20 phr, and again very preferably 10 to 20 phr of at least one butadiene rubber and / or styrene-butadiene rubber. The rubber mixture B particularly preferably contains 80 to 90 phr of at least one natural and / or synthetic polyisoprene and 10 to 20 phr of at least one butadiene rubber. This results in very good tear properties.

[0034] Preferably, rubber mixture A contains 10 phr to 45 phr of filler(s). This means that rubber mixture A can contain one filler or several different ones of the above-mentioned fillers.

[0035] The rubber mixture A preferably contains 0 phr to 40 phr, more preferably 20 phr to 40 phr, and most preferably 30 phr to 40 phr of at least one carbon black. The carbon black can be any type known to the person skilled in the art.

[0036] However, it is advantageous for the physical properties of the rubber compound A, in particular for the rebound resilience at 70 °C, if the carbon black contained in the rubber compound A has a BET surface area according to DIN ISO 9277 and DIN 66132 of 30 m 2 / g up to 150 m 2 / g, particularly preferably 30 m 2 / g up to 115 m 2 / g and especially preferably from 70 m 2 / g up to 115 m 2 / g. Particularly preferred carbon blacks are therefore carbon blacks of the type N220 and / or N339.

[0037] Furthermore, the rubber mixture A preferably contains silica as a second filler, in amounts of 0 phr to 10 phr, particularly preferably 0.1 phr to 7 phr and very particularly preferably 2 phr to 7 phr.

[0038] The rubber mixture B preferably contains 0 phr to 100 phr, more preferably 20 phr to 100 phr, and most preferably 41 phr to 100 phr of at least one carbon black. The carbon black can be any type known to the person skilled in the art.

[0039] However, it is advantageous for the physical properties of the rubber compound B, in particular for the rebound resilience at 70 °C, if the carbon black contained in the rubber compound B has a BET surface area according to DIN ISO 9277 and DIN 66132 of 30 m 2 / g up to 150 m 2 / g, particularly preferably 30 m 2 / g up to 130 m 2 / g and especially preferably from 95 m 2 / g up to 130 m 2 / g. Particularly preferred carbon blacks are therefore carbon blacks of the type N220 and / or N339.

[0040] Furthermore, the rubber mixture B preferably contains silica as a second filler in amounts of 0.1 phr to 40 phr, particularly preferably 3 phr to 40 phr and very particularly preferably 3 phr to 20 phr.

[0041] The silicas contained in rubber mixtures A and B can be any type of silica known to the person skilled in the art. The terms "silica" and "silica" are used synonymously in the present invention, and silica types known to the expert are considered silicas for the purposes of the present invention.

[0042] It is advantageous for the physical properties of the rubber mixtures A and B if the silicas contained in the rubber mixtures A and B have a BET surface area according to DIN ISO 9277 and DIN 66132 of 120 m 2 / g up to 240 m 2 / g, particularly preferably 160 m 2 / g up to 220 m 2 / g and especially preferably from 180 m 2 / g up to 200 m 2 / g.

[0043] The rubber mixtures A and B can also contain known coupling agents, in particular silane coupling agents, in amounts of 0 phr to 20 phr for binding the silica. All silane coupling agents known to the person skilled in the art for use in rubber mixtures can be used as silane coupling agents. 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 have, as another functionality, a group that can, optionally after cleavage, enter into a chemical reaction with the double bonds of the polymer. The latter group can be, for example, the following chemical groups: -SCN, -SH, -NH2, or -Sx- (where x = 2 to 8).

[0044] For example, 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane, or 3,3'-bis(triethoxysilylpropyl)polysulfides with 2 to 8 sulfur atoms, such as 3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT), the corresponding disulfide (TESPD), or mixtures of sulfides with 1 to 8 sulfur atoms with varying contents of the various sulfides, can be used as silane coupling agents. TESPT can also be added, for example, as a mixture with carbon black (trade name X50S® from Evonik).

[0045] Preferably, a silane mixture is used which contains 40 to 100 wt.% disulfides, particularly preferably 55 wt.% to 85 wt.% disulfides and very particularly preferably 60 wt.% to 80 wt.% disulfides.

[0046] Blocked mercaptosilanes, such as those known from WO 99 / 09036, can also be used as silane coupling agents. Silanes such as those described in WO 2008 / 083241 A1, WO 2008 / 083242 A1, WO 2008 / 083243 A1, and WO 2008 / 083244 A1 can also be used. Examples of suitable silanes include those marketed under the name NXT in various versions by Momentive, USA, or those marketed under the name VP Si 363® by Evonik Industries.

[0047] The rubber mixture A preferably contains 0 phr to 5 phr of silane, particularly preferably 0 phr of silane, ie the rubber mixture A is particularly preferably free of silanes.

[0048] The rubber mixture B preferably contains 0.1 phr to 20 phr of at least one of the silanes listed above, particularly preferably 10 phr to 17 phr of at least one of the silanes listed above.

[0049] The vulcanization of rubber compounds A and B takes place in the presence of sulfur and / or sulfur donors as well as vulcanization accelerators, whereby some vulcanization accelerators can also act as sulfur donors. Sulfur or sulfur donors as well as one or more accelerators are added to the rubber compound in the specified amounts during the final mixing step. The terms "sulfur donor" and "sulfur-donating substance" are used synonymously in this application. Furthermore, the term "sulfur donor" is commonly used for sulfur donors.

[0050] The accelerator is selected from the group containing thiazole accelerators and / or mercapto accelerators and / or sulfenamide accelerators and / or thiocarbamate accelerators and / or thiuram accelerators and / or thiophosphate accelerators and / or thiourea accelerators and / or xanthate accelerators and / or guanidine accelerators.

[0051] In a preferred embodiment of the invention, a sulfenamide accelerator selected from the group containing N-cyclohexyl-2-benzothiazolesufenamide (CBS) and / or N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS) and / or benzothiazyl-2-sulfenemorpholide (MBS) and / or N-tert-butyl-2-benzothiazylsulfenamide (TBBS) is used.

[0052] The sulfur-donating substance is preferably selected from the group containing, for example, thiuram disulfides, such as tetrabenzylthiuram disulfide (TBzTD) and / or tetramethylthiuram disulfide (TMTD) and / or tetramethylthiuram monosulfide (TMTM) and / or tetraethylthiuram disulfide (TETD), and / or thiuram tetrasulfides, such as dipentamethylenethiuram tetrasulfide (DPTT), and / or dithiophosphates, such as DipDis (bis-(diisopropyl)thiophosphoryl disulfide) and / or bis(O,O-2-ethylhexyl-thiophosphoryl)polysulfide (e.g. Rhenocure SDT 50®, Rheinchemie GmbH) and / or zinc dichloryldithiophosphate (e.g. Rhenocure ZDT / S®, Rheinchemie GmbH) and / or zinc alkyldithiophosphate, and / or 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane and / or diarylpolysulfides and / or dialkylpolysulfides and / or 3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT).

[0053] Thus, silanes, which can release sulfur during vulcanization, can also be involved in the vulcanization.

[0054] Other network-forming systems, such as those sold under the trade name Vulkuren ® , Duralink ® or Percalink ® available, or network-forming systems as described in WO 2010 / 049261 A2 can be used in rubber compounds A and B.

[0055] In addition, vulcanization retarders may be present in rubber compounds A and B.

[0056] The rubber mixture A preferably contains 1 phr to 6 phr, more preferably 1.4 phr to 2 phr, and most preferably 1.4 phr to 1.8 phr of at least one of the above-mentioned vulcanization accelerators. Furthermore, the rubber mixture A preferably contains 0 phr to 4 phr, more preferably 1.2 phr to 2 phr, of sulfur, with the sulfur preferably being added to the rubber mixture as elemental sulfur.

[0057] Rubber mixture B preferably contains 1 phr to 6 phr, more preferably 1.0 phr to 2 phr, and most preferably 1.0 phr to 1.5 phr of at least one of the above-mentioned vulcanization accelerators. Furthermore, rubber mixture A preferably contains 0 phr to 4 phr, more preferably 1.0 phr to 1.3 phr of sulfur, with the sulfur preferably being added to the rubber mixture as elemental sulfur.

[0058] Furthermore, rubber compounds A and B may contain conventional additives in the usual parts by weight. These additives include a) Anti-aging agents 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), 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), b) activators such as zinc oxide (ZnO) and fatty acids (e.g. stearic acid), c) waxes, d) Plasticizers, such as mineral oil plasticizers e) Hydrocarbon resins other than plasticizers f) mastication aids such as 2,2'-dibenzamidodiphenyl disulfide (DBD).

[0059] Rubber mixtures A and B preferably contain at least one zinc oxide as an activator. All types of zinc oxide known to those skilled in the art are suitable. For example, the ZnO used can be in powder or granular form. It can also be nanoscale zinc oxide.

[0060] Zinc oxide is used in comparatively small amounts in rubber compounds A and B. The amount of zinc oxide is 0.1 phr to 4 phr, preferably 0.1 phr to 3.5 phr, and particularly preferably 2.5 phr to 3.5 phr.

[0061] According to the invention, the base is constructed from different rubber mixtures A and B in such a way that the rubber mixture A and the rubber mixture B are arranged in three or more radially superimposed layers.

[0062] The sum of the number of layers of the rubber mixture A and the number of layers of the rubber mixture B is preferably up to 13, particularly preferably up to 8, wherein the layers of the rubber mixtures A and B are arranged alternately radially one above the other.

[0063] In an advantageous embodiment of the invention, the radially outermost layer of the base consists of the rubber mixture B. As a result, the base is particularly well protected radially outwards against penetrating stones and cracking.

[0064] In a further advantageous embodiment of the invention, the base consists of three layers in the sequence ABA, where A and B are the described rubber compounds. This results in particularly good rolling resistance behavior of the pneumatic vehicle tire, along with good crack resistance and comparatively simple manufacturing due to the number of layers. Any stones that may penetrate to the base are prevented by layer B from further penetrating the radially inner components of the pneumatic vehicle tire.

[0065] In a further advantageous embodiment of the invention, the base consists of five layers in the ABABA sequence, where A and B are the described rubber compounds. This results in particularly good rolling resistance of the pneumatic vehicle tire with good crack resistance. Any stones that may penetrate to the base are prevented by layer B from further penetrating the radially inner components of the pneumatic vehicle tire.

[0066] In a further advantageous embodiment of the invention, the base consists of six layers, with three layers each of the rubber mixtures A and B being arranged alternately radially one above the other. It is particularly preferred if the radially outermost layer of the base, i.e. the layer closest to the cap of the tread, is the rubber mixture B. The radially innermost layer of the base, i.e. the layer closest to the belt package of the pneumatic vehicle tire, is the rubber mixture A. This construction has the advantage that the rubber mixture A generates as little heat build-up as possible at the belt and the base is protected as well as possible radially outwards against penetrating stones or crack propagation by the rubber mixture B.

[0067] The layer thickness of the individual layers of rubber mixtures A and B is 0.4 mm to 1.6 mm each, preferably 0.4 mm to 1.1 mm, and most preferably 0.5 mm to 1 mm. The pneumatic vehicle tire according to the invention is preferably such that the layers of rubber mixtures A and B have the same layer thicknesses, with the above-mentioned layer thicknesses applying.

[0068] A pneumatic vehicle tire with equal layer thicknesses of the individual layers of the base is particularly easy to manufacture, especially with regard to the extrusion of the mixtures for forming the unvulcanized tire components.

[0069] The pneumatic vehicle tire according to the invention is in particular such that the total thickness of the base, consisting of at least three layers of the rubber mixtures A and B, is 10% to 115%, preferably 10% to 50% of the total thickness of the cap.

[0070] The invention will now be explained in more detail using examples and embodiments.

[0071] Table 1 summarizes the physical data of test specimens E1, which according to the invention have a layer structure consisting of different numbers of layers of the two rubber mixtures A and B, compared to the respective references A and B. The samples listed under E1 have a layer structure consisting of alternating rubber mixtures A and B, with each layer being 1 mm thick. The right-hand column of Table 1 shows how many layers of rubber mixtures A and B were used in the test specimens for the respective test. The thickness of the test specimens of the pure rubber mixtures A and B is the same as that of the test specimens with the layer structure. Table 1 also lists the expected value, i.e. the value for the respective test that would be expected based on the individual results A and B weighted by the number of layers A and B in test specimen E1.

[0072] The rubber compounds A and B were mixed under standard conditions in three stages in a laboratory tangential mixer.

[0073] The test specimens described above were produced from mixtures A and B by optimal vulcanization under pressure at 140 °C and, using these test specimens, material properties typical for the rubber industry were determined using the test procedures specified below. • Shore A hardness at room temperature (RT) according to DIN ISO 7619-1 • Rebound resilience at 70 °C according to DIN 53 512 • Tangent delta (tan δ) at 60 °C from dynamic-mechanical measurement according to DIN 53513 and 53535 • Loss modulus E'' from dynamic-mechanical measurement (temperature sweep, T-sweep) according to DIN 53513 and 53535 • Crack propagation according to De Mattia: the length of the crack is measured after 128 kilo-cycles according to DIN 53522-1 / 2 / 3 • Tear resistance according to Graves in accordance with DIN 53515 Table 1 Components Unit A B NR phr 100 85 BR phr 0 15 soot a) phr 34 45 Silica b) phr 5 12 Additive phr 9,7 10,6 Vulcanization accelerator phr 1,6 1,1 sulfur phr 1,4 1,1 Physical properties A B Expected value E1 Number of layers A / B of the E1 specimens Rebound 70°C % 71 58 65 67 5 / 4 Tan δ at 60 °C 0,0954 0,1493 0,120 0,112 7 / 6 De Mattia crack propagation mm 16 7 12 13 5 / 4 Tear resistance N / mm 52 70 60 59 3 / 2 Loss modulus E'' at 60 °C MPa 0,423 0,748 0,573 0,509 7 / 6 Shore A hardness Shore A 58,2 59,55 58,8 58,45 5 / 4 a) Carbon black: N220; b) Silica: HISIL™ 255, PPG Industries

[0074] As shown in Table 1, the E1 specimens exhibit good tear properties combined with good rolling resistance behavior, as evidenced by the rebound resilience indicators at 70 °C and the tangent delta at 60 °C. The properties of the individual E1 specimens are even better than the respective expected values.

[0075] Due to this synergistic effect, the inventive combination of two different mixtures, which are arranged radially one above the other in layers in the base of pneumatic vehicle tires, achieves an improvement in the conflict of objectives between rolling resistance behavior and tear properties.

[0076] In Fig.Figure 1 shows, by way of example, a schematic cross-section of a pneumatic vehicle tire according to the invention. The pneumatic vehicle tire with a cap / base structure has a cap 1 and a base 2, wherein the base 2 consists of alternating layers 2a and 2b of the rubber mixtures A (layer 2a) and B (layer 2b), respectively. Fig. 1 shows, as an example, three layers 2a of the rubber mixture A and two layers 2b of the rubber mixture B.

[0077] The total thickness 3 of the tread consisting of Cap 1 and Base 2 is measured in the radial direction perpendicular to the direction of extension of the tread from the radially outermost point of Cap 1 to the radially innermost point of Base 2.

[0078] The total thickness 3 of the tread consisting of Cap 1 and Base 2 is therefore composed of the total thickness 4 of Cap 1 and the total thickness 5 of Base 2. The total thickness 5 of Base 2, consisting of at least three layers 2a and 2b of rubber compounds A and B, is 10% to 115% of the total thickness 4 of Cap 1.

[0079] The pneumatic vehicle tire according to the invention has a belt package 7, which in the exemplary Fig. 1 consists of three belt layers 6. Each belt layer contains 6 reinforcements that are coated with at least one rubber compound. In the example of Fig. 1, the pneumatic vehicle tire includes a sub-plate 8 located between the base 2 of the tread and the belt package 7. List of reference symbols: 1 cap 2 Base 2a shift 2b layer 3 Total thickness of the tread 4 Total thickness of the cap 5 Total thickness of the base 6 Belt layer 7 Belt package 8 Base plate

Claims

[1] Pneumatic vehicle tyre with a tread with a cap (1) / base (2) structure, wherein the cap (1) contains the profile of the tread and the base (2) consists of two different rubber compounds A and B, characterized by that three or more layers (2a, 2b) of the rubber mixtures A and B are arranged radially one above the other, wherein the layers (2a, 2b) of the rubber mixtures A and B are arranged alternately radially one above the other and wherein the rubber mixture A has a rebound resilience at 70 °C according to DIN 53512 of 62% to 85% and the rubber mixture B has a rebound resilience at 70 °C according to DIN 53512 of 30% to 60%. [2] Pneumatic vehicle tyre according to claim 1, characterized by that the rubber compound A contains 10 phr to 45 phr filler(s). [3] Pneumatic vehicle tyre according to one of the preceding claims, characterized by that the rubber compound B contains 46 phr to 100 phr filler(s). [4] Pneumatic vehicle tyre according to one of the preceding claims, characterized by that the radially outermost layer (2b) of the base (2) consists of the rubber mixture B. [5] Pneumatic vehicle tyre according to one of the preceding claims, characterized by that the total thickness (5) of the base (2), consisting of three or more layers (2a, 2b) of the rubber mixtures A and B, is 10% to 115% of the total thickness (4) of the cap (1). [6] Pneumatic vehicle tyre according to one of the preceding claims, characterized by that the layers (2a, 2b) of the rubber mixtures A and B have the same layer thicknesses. [7] Pneumatic vehicle tyre according to one of the preceding claims, characterized by that it has a base plate (8) between the base (2) and the belt package (7).

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