rubber compound and tires

Abstract

The invention relates to a sulfur-crosslinkable rubber compound, in particular for the tread of vehicle tires, containing at least the following components: - at least one diene rubber, - 5 to 70 phr (parts by weight, based on 100 parts by weight of the total rubbers in the compound) of at least one terpene resin, - 5 to 80 phr of at least one rubber regenerate, and - 40 to 350 phr of at least one filler.

Description

The invention relates to a sulfur-crosslinkable rubber mixture, in particular for the tread of vehicle tires.The invention further relates to a pneumatic vehicle tire having at least one component which consists of such a sulfur-vulcanized rubber mixture.Since the driving properties of a tire, in particular pneumatic vehicle tires, are to a large extent dependent on the rubber composition of the tread, particularly high requirements are placed on the composition of the tread mixture. This is accompanied by conflicts in goals between most of the known tire properties such as wet grip behavior, braking behavior, handling behavior, rolling resistance, winter properties, abrasion behavior and tear properties. Various attempts have already been made to positively influence the properties of the tyre by varying the polymer components, the fillers and the other additives in the tread mixture.In addition to the above-mentioned goals with regard to the mixing and vulcanisate properties, efforts are nowadays made to use materials which are as durable and environmentally friendly as possible in rubber mixtures for vehicle tires, to reduce the dependence on fossil raw materials and to minimize the output of greenhouse gases.One way to make lasting products is through recycling of old, no longer needed products, such as recycling of old tires, whereby the recycled material is recycled into the production of new tires. It is known from the prior art, for example, that rubber materials can be processed from old conveyor belts or used tires in order to be used as an additive in vulcanizable rubber mixtures, which can subsequently be shaped during the production of tires or other rubber products and vulcanized to give the desired rubber products. These so-called rubber regenerates can in principle be prepared in various ways. In particular, materials prepared from the prior art are known, which in the narrower sense are also a rubber material, i.e. crosslinked rubber, the plasticity of which, however, is adapted to the plasticity of unvulcanized rubber by means of suitable treatment methods, in particular using thermochemical stressing and chemicals. A process for the production of rubber regenerated material with special regenerating agents is described, for example, in DE 10 2012 108 096 A1. In addition, there are rubber regenerates in which at least partially devulcanization, i.e. the breaking of chemical bonds in the rubber material, occurs and in which correspondingly the depolymerization of the previously crosslinked rubber material contributes to an increase in plasticity.Various technologies and methods are used for producing rubber regenerates from rubber materials, for example steam regeneration, mechanical regeneration, thermal regeneration, acoustic wave-based regeneration, radiation-based regeneration, chemical regeneration and combinations of these methods.Another way of improving the sustainability of products is to use substances of renewable raw materials as additives for rubber mixtures. Additives of this type made from renewable raw materials are, for example, vegetable oils, resins based on renewable raw materials or rice hull silica. The latter is silica made from bio-based sodium silicate from rice hull ash.It is an object of the invention to provide durable rubber mixtures for the treads of vehicle tires which are distinguished by improved rolling resistance and improved mechanical-structural durability.This object is achieved according to the invention by a sulfur-crosslinkable rubber mixture, in particular for the tread of vehicle tires, which contains at least the following constituents:at least one diene rubber,5 to 70 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one terpene resin,5 to 80 phr of at least one rubber recovery agent, and40 - 350 phr of at least one filler.Surprisingly, it has been found that the specific combination of at least one terpene resin with a rubber regenerated compound in the amounts specified in a filler-containing diene rubber mixture leads to a reduced loss factor tan δ (10%) from RPA measurement (=and "rubber process analyzer") on the conditioned sample on the basis of ASTM D6601. This reduced loss factor tan δ (10%) can be correlated with a reduced rolling resistance when the mixture is used in tire treads. At the same time, the mixtures after vulcanization have a higher high-speed tearing energy (HSTE according to ISO 8256), which is to be regarded as an indicator of better structural durability and better resistance to cuts in and outbreaks from the rubber material.The rubber mixture according to the invention is also distinguished by improved sustainability through the use of rubber regenerated rubber.The stated phr (parts per hundred parts of rubber by weight) used in this specification is the stated amount for mixture formulations customary in the rubber industry. The metered addition of the parts by weight of the individual substances is based in this specification on 100 parts by weight of the total mass of all (primary) rubbers present in the mixture, based on a molecular weight M w according to GPC of greater than 20000 g / mol. The rubber regenerates are not included in the total mass of the high molecular weight rubbers used as primary raw materials. Accordingly, in the context of the present invention, the proportion by mass of the high molecular weight rubbers used as primary raw material in the rubber mixture, i.e. of the rubbers which do not originate from a rubber regenerated material, is added to 100 phr.According to the invention, the rubber mixture contains at least one diene rubber. Diene rubbers are rubbers which are formed by polymerization or copolymerization of dienes and / or cycloalkenes and thus have C=C double bonds either in the main chain or in the side groups. The diene rubber(s) is or 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 having a molecular weight M w of 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.Nitrile rubber, hydrogenated acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber or ethylene-propylene-diene rubber are used in particular in the production of industrial rubber articles, such as belts, belts and hoses, and / or shoe soles. The preferred mixing compositions known to the skilled person for these rubbers are used with regard to fillers, plasticizers, vulcanization systems and additives.According to a particularly preferred embodiment of the invention, the diene rubber(s) is selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution polymerized styrene butadiene rubber (SSBR), and emulsion polymerized styrene butadiene rubber (ESBR). Such a rubber mixture is suitable in particular for the tread of vehicle tires. Natural polyisoprene is understood as rubber which can be obtained by harvesting sources such as rubber trees (Hevea brasiliensis) or non-rubber tree sources (such as guayule or löwen tooth (e.g. Taraxacum kokoaghyz)). Natural polyisoprene (NR) is not understood to mean synthetic polyisoprene.The rubber mixture contains 5 to 70 phr, preferably 10 to 60 phr, particularly preferably 20 to 50 phr of at least one terpene resin. It is also possible to use a plurality of different terpene resins. Terpene resins are hydrocarbon resins obtained by polymerization of terpenes. Included among the terpene resins are copolymers of terpernes and other monomers such as styrene and isoprene.The terpene resins used may have different average molecular weights. The at least one terpene resin preferably has an average molecular weight M w according to GPC of 800 to 1500 g / mol. Terpene resins of this type can be processed well and lead to good tear properties.According to a preferred development of the invention, the terpene resin has a softening point of 100 to 140° C., preferably 110 to 130° C.For good braking performance of a tire whose tread consists of the rubber mixture according to the invention, the terpene resin has a glass transition temperature Tg according to DSC of from 50 to 100° C., preferably from 50 to 80° C.According to a preferred development of the invention, the at least one terpene resin is based to an extent of more than 95% on biologically renewable raw materials. This helps to improve the sustainability of the rubber composition. The term "a terpene resin based to an extent of more than 95% on biologically renewable raw materials" is understood in the context of the present invention to mean a terpene resin which is produced materially from renewable raw materials as a source, with vegetable sources being preferred in particular.The terpene resin is preferably based to an extent of 100% on biologically renewable raw materials.Terpene resins which are based to an extent of more than 95% on biologically renewable raw materials can be obtained, for example, from raw materials which are obtained in the production of fragrances from orange peels. Preferably, however, the terpene resin is based on by-products which are produced in the chemical manufacture of coniferous woods. Such by-products are available on the market in large quantities and can be upgraded on an industrial scale to terpene resins.According to a preferred development of the invention, the at least one terpene resin is not based on limonene.Preferably, the at least one terpene resin is based on α- and β-pinene. Such terpene resins can be produced from by-products which are produced in the chemical manufacture from coniferous woods.It is also possible within the scope of the invention to use different terpene resins from different sources.Terpene resins which can be used according to the invention include, for example, those of the type Sylvatraxx® 8115, and Sylvatraxx® 8125 from Kraton Chemicals SAS. These are not based on limonene. They are 100% based on biologically renewable raw materials.The rubber mixture contains 5 to 80 phr, preferably 5 to 40 phr, of at least one rubber regenerate. The rubber regenerates may be prepared by different methods and / or different regenerating agents, and different starting materials may be used for the regeneration.In order to improve the tear strength of the vulcanizates, it has proven advantageous if the at least one rubber regenerated material was produced from a rubber material mixture in an internal mixer by means of at least one regenerating agent selected from the group consisting of dithiophosphoryl polysulfides and silanes having a polysulfane group, wherein the rubber material mixture consists of at least 50% by weight of comminuted tread strips of truck radial tires and / or bus radial tires.According to a preferred embodiment of the invention, the dithiophosphoryl polysulfide has the general formula I wherein R 1 and R 2 are identical or different and are selected from linear or branched C 3- to C 20- alkyl radicals and x=1 to 6.Particularly preferably, the dithiophosphoryl polysulfide is a bis-(O,O-2-ethylhexyl) thiophosphoryl polysulfide.According to a preferred embodiment of the invention, at least one silane having a polysulfane group of the general formula II or a mixture comprising at least one silane having a polysulfane group of the general formula II (R 2 O) 3-y R 3y- Si-R 1- S x- R 1- Si-(OR 2)3-z R 3z( II) where x=1 to 8 and where the R 1 in one molecule are identical or different and are selected from linear or branched C 1- to c 18- alkyl radicals, where the R 2 and R 3 in a molecule are identical or different and are selected from linear or branched or cyclic saturated C 1- to C 30- alkyl radicals, and where y and z are identical or different and are 0 to 3. The number of hydrogen atoms of the alkyl radicals is given by the number of carbon atoms. Preferably, x=1 to 5, particularly preferably x=2 to 4 and in a very particularly preferred embodiment, x=4.According to a particularly preferred development, the silane having a polysulfane group is a Bis(trialkoxysilyl)propylpolysulfan. Here, z=0, R 1 is a propyl radical and R 2 is an alkyl radical having 1 to 30 carbon atoms. This silane has the general constitutional formula III (R 2 O) 3- Si-(CH 2)3- S x-( CH 2)3- Si-(OR 2)3. (III) Most preferably, the R 2 group is an ethyl group, so that the silane having a polysulfane group is a Bis(triethoxysilyl)propylpolysulfan group.According to a further preferred development of this embodiment of the invention, the radicals R 2 and / or R 3 of the silane having a polysulfane group additionally contain 1 to 10 nitrogen atoms (N) and / or oxygen atoms (O) as heteroatoms in the carbon chain. According to this further development of the invention, it is conceivable that the radicals R 2 and / or R 3 represent, for example, a unit having the constitutional formula IV -(CH 2- CH 2- O) 5-( CH 2)12 CH 3. (IV)In this case, the radicals R 2 and / or R 3 contain five oxygen atoms as heteroatoms.In a further embodiment of the invention, the silane having a polysulfane group has the general formula V (R 2 O)3-yR 3 y-Si-R 1- Sx-R 1- Si-(O 2 R 2) R 3( V), where x=1 to 8 and where the R1in a molecule are identical or different and are selected from linear or branched C 1- to C 18- alkyl radicals, wherein R 2 in a molecule are the same or different and are selected from linear or branched or cyclic saturated C 1- to C 30- alkyl radicals, and wherein y and z are the same or different and 0 to 3 and wherein R 3 in a molecule are the same or different and are selected from linear or branched C 1- to C 10- alkyl or alkoxy radicals. In this embodiment, a radical R 2 can bridge two oxygen atoms to one another.In a further embodiment of the invention, the silane having a polysulfane group has the general formula VI (R 2 O 2) R 3- Si-R 1- Sx-R 1- Si-(O 2 R 2) R 3( VI), where x=1 to 8 and where the R1in a molecule are identical or different and are selected from linear or branched C 1- to C 18- alkyl radicals, wherein R 2 in a molecule are the same or different and are selected from linear or branched or cyclic saturated C 1- to C 30- alkyl radicals, and wherein R 3 in a molecule are the same or different and are selected from linear or branched C 1- to C 10- alkyl or alkoxy radicals. In this embodiment, a radical R 2 at both ends of the molecule can bridge two oxygen atoms to one another.Preferably, the regenerating agent is selected from bis(O,O-2-ethylhexylthiophosphoryl) polysulfide and / or (Bis(triethoxysilyl)propyltetrasulfan (TESPT)). The substances can be used individually or in a mixture.The rubber regenerated material preferably used according to the invention can be obtained, for example, by the following, mild degradation process with at least the following process steps:providing the sulfur-crosslinked rubber material mixture to be regenerated in amounts of 68 to 98% by weight in an internal mixer; andheating the sulfur-crosslinked rubber material mixture to be regenerated to 50 to 70° C.; andadding at least one dithiophosphoryl polysulfide and / or at least one silane having a polysulfane group in amounts of from 2 to 15% by weight, andmixing said components into a mixture for a period of 5 to 35 minutes at a temperature of 80 to 150° C.Methods for producing rubber regenerates which can be used for the invention are described, for example, in DE 10 2012 108 096 A1.Rubber materials which are used in different rubber products regularly have very different physicochemical or mechanical properties, which can be attributed in particular to the chemical composition of the vulcanizable rubber mixtures used for the production. Rubber materials accordingly behave differently during the production of regenerated material and result in chemically different rubber regenerates. In practice, the choice of starting material is thus of important importance. In the present case, the inventors have found that rubber materials from the tread strips of radial tires for trucks and buses, which are characterized by a typical application profile of properties, have a particularly high compatibility with the process for producing the regenerated material, and the resulting rubber regenerates are particularly suitable for use in vulcanizable rubber mixtures with silica in the specific silanes. For the most durable possible production of the rubber mixture according to the invention, the rubber material mixture consists of at least 50% by weight, preferably of at least 70% by weight, particularly preferably to the extent of substantially 100% by weight, of comminuted tread of recycled truck radial tires and / or recycled bus radial tires, based on the mass of the rubber material mixture. Recycled tires are said to be used previously and have accordingly been at least partially shut down.The rubber material mixture preferably contains no detectable residues of butyl or halobutyl rubbers and no more than 0.01 wt.% of fiber residues.The rubber mixture contains 40 to 350 phr of at least one filler. The fillers may be fillers, such as carbon blacks, silicas, aluminosilicates, chalk, starch, magnesium oxide, titanium dioxide or rubber gels, in customary amounts, it being possible for the fillers to be used in combination. Furthermore, carbon nanotubes (CNTs) including discrete CNTs, so-called hollow carbon fibers (HCFs) and modified CNTs containing one or more functional groups, such as hydroxyl, carboxyl and carbonyl groups), are conceivable. Graphite and graphenes and also so-called "carbon-silica dual-phase filler" can also be used as filler. Different fillers can be used in the mixture.If carbon black is present in the rubber mixture, all carbon black types known to the skilled worker can be used. However, preference is given to using a carbon black which has an iodine adsorption number according to ASTM D 1510 of 30 to 180 g / kg, preferably 30 to 130 kg / g, and a DBP number according to ASTM D 2414 of 80 to 200 ml / 100 g, preferably 100 to 200 ml / 100 g, particularly preferably 100 to 180 ml / 100 g. Particularly good rolling resistance indicators (rebound resilience at 70° C.) with good other tire properties are thereby achieved for use in the vehicle tire.To reduce the rolling resistance, it has proven advantageous if the rubber mixture contains 20 to 200 phr of silica as filler. In addition, further fillers, such as carbon black, are present in the mixture, so that a proportion of 40 to 350 phr of total filler is present in the mixture.A wide variety of silicas, such as low surface area or highly dispersible silica, can be used, including as a mixture. It is particularly preferred if a finely divided, precipitated silica is used which has a CTAB surface area (according to ASTM D 3765) of from 30 to 350 m 2 / g, preferably from 110 to 250 m 2 / g. The silicas used may be either conventional silicas such as those of the type VN3 (trade name) from Evonik, or highly dispersible silicas, known as HD silicas (for example Ultrasil 7000 from Evonik). Silicas produced from rice hull ash ("rice husk ash silica" (RHAS)) are also suitable.To improve the processability and to attach the silica to the diene rubber in siliceous mixtures, preferably at least one silane coupling agent is used in amounts of 1-15 phf (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 a mixture.The stated phf (parts per hundred parts of filler by weight) used in this specification is the stated amount of coupling agents for polar fillers which is customary in the rubber industry. In the context of the present application, phf refers to the silica / silica present, i.e. other fillers that may be present, such as carbon black, do not participate in the calculation of the amount of silane coupling agent.The silane coupling agents react with the surface silanol groups of the silica or other polar groups during the mixing of the rubber or of the rubber mixture (in situ) or already before the addition of the filler to the rubber in the sense of a pretreatment (pre-modification). The silane coupling agents used can be all silane coupling agents known to the skilled person for use in rubber mixtures. Such coupling agents known from the prior art are bifunctional organosilanes which have at least one alkoxy, cycloalkoxy or phenoxy group as leaving group on the silicon atom and which have as other functionality a group which, if appropriate after cleavage, can 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, -NH 2 or -S x- ( where x=2-8). Thus, for example, 3-mercaptopropyltriethoxysilane, 3-thiothionopropyltrimethoxysilane or 3,3'-bis(triethoxysilylpropyl)polysulfides having 2 to 8 sulfur atoms, such as, for example, 3,3'-bis(triethoxysilylpropyl)tetrasulfide (TESPT), the corresponding disulfide or else mixtures of the sulfides having 1 to 8 sulfur atoms with different 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 Degussa). Blocked mercaptosilanes, as are known, for example, from WO 99 / 09036, can also be used as silane coupling agent. It is also possible to use silanes as described in WO 2008 / 083241 A1, WO 2008 / 083242 A1, WO 2008 / 083243 A1 and WO 2008 / 083244 A1. Usable are, for example, silanes sold under the name NXT ® in various variants by Momentive, USA, or those sold under the name VP Si 363 by Evonik Industries. It is also possible to use so-called "silylated core polysulfides" (SCP), which are described, for example, in U.S. Pat. No. 20080161477 A1 and EP 2 114 961 B1.Preferably, at least one silane coupling agent in the rubber mixture is a blocked mercaptosilane.The rubber mixture according to the invention can furthermore contain different plasticizers. These are preferably present in the mixture in amounts of up to 50 phr.Plasticizers which can be used are, for example, those selected from the group consisting of plasticizers from renewable raw materials such as rapeseed oil or sunflower oil, mineral oils, phosphoric esters such as tri(2-ethylhexyl)phosphate, and liquid polymers having a weight average molecular weight distribution M w by GPC of 60,000 g / mol or less. Preference is given to using DAE (distilled aromatic extracts), RAE (residual aromatic extract), TDAE (treated distilled aromatic extracts), MES (mild extracted solvents), rapeseed oil and / or liquid diene polymers.The rubber mixture may furthermore comprise customary additives in customary parts by weight, which are preferably added in at least one basic mixing stage during the preparation thereof. These additives include a) anti-ageing agents, such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PP), 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 and fatty acids (e.g. stearic acid), or zinc complexes, such as zinc ethylhexanoate, c) waxes, d) masticating auxiliaries, such as 2,2'-dibenzamidodiphenyl disulfide (DBD), and e) processing auxiliaries, such as fatty acid salts, such as zinc soaps, and fatty acid esters and derivatives thereof.The proportion of the total amount of further additives is 3 to 150 phr, preferably 3 to 100 phr and particularly preferably 5 to 80 phr.The vulcanization of the rubber mixture is carried out in the presence of sulfur and / or sulfur donors with the aid of vulcanization accelerators, it being possible for some vulcanization accelerators to act simultaneously as sulfur donors. The accelerator is selected from the group consisting of 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. Preference is given to the use of a sulfenamide accelerator selected from the group consisting of N-cyclohexyl-2-benzothiazolesulfenamide (CBS) and / or N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS) and / or benzothiazyl-2-sulfenomorpholide (MBS) and / or N-tert-butyl-2-benzothiazylsulfenamide (TBBS).In addition, the rubber mixture may contain vulcanization retarders.All sulfur-donating substances known to the skilled person can be used as sulfur-donating substance. If the rubber mixture contains a sulfur-donating substance, this is preferably selected from the group consisting of, for example, thiuram disulfides, such as, for example, tetrabenzylthiuram disulfide (TBzTD), tetramethylthiuram disulfide (TMTD) or tetraethylthiuram disulfide (TETD), thiuram tetrasulfides, such as, for example, dipentamethylenethiuram tetrasulfide (DPTT), dithiophosphates, such as, for example, DipDis (bis-(diisopropyl)thiophosphoryl disulfide), bis(O,O-2-ethylhexylthiophosphoryl)dithiophosphoryl)dithioamines (for example Rhenocure SDT 50 ®, Rheinchemie GmbH, Zinc dichlorodithiophosphate (e.g. Rhenocure ZDT / S ®, Rheinchemie GmbH) or zinc alkyldithiophosphate, and 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane and diaryl polysulfides and dialkyl polysulfides.Other network-forming systems, as are available, for example, under the trade names Vulkuren ®, Duralink ® or Perkalink ® or network-forming systems, as are described in WO 2010 / 049216 A2, can also be used in the rubber mixture. The latter system contains a vulcanization agent which crosslinks with a functionality greater than four and at least one vulcanization accelerator.During their production, at least one vulcanizing agent selected from the group consisting of sulfur, sulfur donors, vulcanization accelerators and vulcanizing agents which crosslink with a functionality of greater than four is preferably added to the rubber mixture in the finish mixing stage. As a result, a sulfur-crosslinked rubber mixture for use in rubber products, in particular in pneumatic vehicle tires, can be produced from the mixed ready-to-use mixture by vulcanization.The terms "vulcanized" and "crosslinked" are used interchangeably within the scope of the present invention.The rubber mixture is produced by the process customary in the rubber industry, in which a masterbatch is first prepared in one or more mixing stages with all constituents other than the vulcanization system (sulfur and vulcanization-influencing substances). By adding the vulcanization system in a final mixing stage, the final mixture is produced. The finished mixture is further processed, for example, by an extrusion process and is brought into the corresponding shape. The further processing is then carried out by vulcanization, wherein sulfur crosslinking takes place on account of the vulcanization system added in the context of the present invention.The rubber mixture can be used for a wide variety of rubber products. It is preferably used for the production of pneumatic vehicle tires, such as passenger car, van, truck or two-wheeler tires, the rubber mixture forming at least that part of the tread which comes into contact with the roadway. However, the rubber mixture can also be used in other tires, such as solid tires and non-pneumatic tires. Similarly, use in the case of round renewal is possible.In a pneumatic vehicle tyre, the tread may consist of a single compound formed according to the invention. However, pneumatic vehicle tires today frequently have a tread with a so-called cap / base construction. The term "cap" is understood here to mean that part of the tread which comes into contact with the roadway and is arranged radially on the outside (tread cap or tread cap). The term "base" is understood here to mean that part of the tread which is arranged radially on the inside and therefore does not come into contact with the roadway during driving operation or comes into contact with the roadway only at the end of tire life (lower tread part or tread base). In a pneumatic vehicle tire having such a cap / base construction, at least the rubber compound for cap is formed according to claim 1.The pneumatic vehicle tire according to the invention can also have a tread which consists of various tread mixtures arranged alongside one another and / or under one another (multi-component tread strips).In the production of the pneumatic vehicle tire, the mixture is brought as a ready-mix before vulcanization into the form of a tread, preferably at least into the form of a tread cap, and is applied as known in the production of the green vehicle tire. The tread, preferably at least the tread cap, can also be wound onto a tyre blank in the form of a narrow rubber compound strip.The invention includes all advantageous embodiments which are reflected, inter alia, in the patent claims. In particular, the invention also includes configurations which result from a combination of different features, for example of constituents of the rubber mixture, different gradations when preference is given to these features, with the result that the invention also covers a combination of a first feature which is referred to as "preferred" or, within the scope of an advantageous embodiment, a further feature which is referred to as "particularly preferred", for example.The invention will now be explained in more detail with reference to comparative and exemplary embodiments, which are summarized in Table 1. The comparative mixtures are marked V, the mixtures according to the invention are marked E.The rubber regenerate for the mixtures given in Table 1 was prepared according to the following process steps in the order given:crushing a rubber material mixture, which consists essentially of 100 wt % crushed tread of truck radial tires and bus radial tires, by means of a cryogenic milling process (pin mill) to form granules having the particle size 0.001 to 0.5 mm,placing 90.7% by weight of the comminuted rubber material mixture to be regenerated in an internal mixer,heating the comminuted rubber material mixture to be regenerated to 60° C.,2 wt. % carbon black (N121) is added,5.5% by weight of the regenerating agent Bis(triethoxysilyl)propyltetrasulfan (TESPT) is added,Addition of 2% by weight of TDAE oil (TDAE= treated aromatic extract),mixing the said constituents to form a rubber regenerated product at a temperature of 100° C. for a period of 20 minutes,cooling the rubber rainerateThe production of the mixture was carried out according to the methods customary in the rubber industry under customary conditions in three stages in a laboratory mixer in which, first, in the first mixing stage (basic mixing stage), all constituents except for the vulcanization system (sulfur and vulcanization-influencing substances) were mixed. In the second mixing stage, the base mixture was mixed again. By adding the vulcanization system in the third stage (finish mixing stage), the finish mixture was produced while mixing at 90 to 120° C.Subsequently, the loss factor tan δ (10%) of the mixture was determined by means of RPA (= "rubber process analyzer") in accordance with ASTM D6601 from the second elongation cycle at 1 Hz, 70° C. and 10% elongation in the vulcanized, conditioned state, wherein the test specimens were produced in the apparatus by vulcanization under pressure at 170° C. for 10 minutes.Furthermore, test specimens were produced from all the mixtures by vulcanization under pressure at 160° C. for 20 minutes, and typical material properties for the rubber industry were determined with these test specimens by the test methods given below:Shore A hardness at room temperature according to ISO 868rebound elasticity at room temperature and 70° C. according to ISO 4662maximum loss factor tan δ max at 55° C. as maximum value over the strain sweep from dynamic mechanical measurement at a frequency of 10 Hz according to ISO 4664-1High-speed tearing energy (HSTE) according to ISO 8256.The maximum loss factor tan δ max at 55° C. (Eplexor) and the loss factor tan δ (10%) by means of RPA can be correlated with the rolling resistance. A low loss factor tan δ max at 55° C. and a low loss factor tan δ (10%) by means of RPA stand for a low rolling resistance. A further indicator of the rolling resistance is rebound elasticity at 70° C. A high value correlates here with good rolling resistance performance. High values of high-speed tearing energy are a measure of high structural durability and good resistance to cuts in and out of the rubber material (good cut-and-chip as well as chip-and-chunk performance). Table 1 Table 1Natural Rubberphr phr phr phr phr phr phr phr phr phr10101010SSBR aphr phr phr phr phr phr phr phr phr phr72727272BR bphr phr phr phr phr phr phr phr phr phr18181818Rubber Regenerated Rubberphr phr phr phr phr phr phr phr phr phr--2020Silica cphr phr phr phr phr phr phr phr phr phr95959595TDAE dphr phr phr phr phr phr phr phr phr phr35-35-Terpene resin ephr phr phr phr phr phr phr phr phr phr-35-35Anti-ageing agents are anti-ageing agentsphr phr phr phr phr phr phr phr phr phr2222Anti-ozone waxphr phr phr phr phr phr phr phr phr phr2222Zinc oxidephr phr phr phr phr phr phr phr phr phr2,52,52,52,5Stearic acid stearic acidphr phr phr phr phr phr phr phr phr phr2,52,52,52,5Silane coupling agent fphr phr phr phr phr phr phr phr phr phr9,79,79,79,7Accelerator Acceleratorphr phr phr phr phr phr phr phr phr phr4444Sulfurphr phr phr phr phr phr phr phr phr phr2222Propertiestan δ (10%) by means of RPA, cut, cond.-0,1400,1660,1490,161Shore hardness at RTShore A66,166,865,365,2Rebound load at RT%30,812,431,514,9Rebound load at 70° C.%51,845,151,246,5tan δ max at 55° C-0,1540,1870,1570,179HSTEEMJ / m 38,412,47,112,4a SSBR Sprintan® SLR-4601, Fa. Trinseob buna CB 1203, arlanxo, T g = -105 ° C., cis-fraction > 95%c Ultrasil® VN3, Evonik, nitrogen surface area=180 m 2 / g, CTAB 165 m 2 / gd TDAE (Treated Distilled Aromatic Extracts), T g = -55 °Ce Sylvatraxx® 8115, Kraton Chemicals SAS, non-limonene based terpene resin, softening point=15°C (according to ASTM E 28), T g = 66 °CfNXT silane, Momentive, 3-mercaptopropyltriethoxysilaneIt is evident from the data of Table 1 that the combined presence of the terpene resin, which is based to an extent of more than 95% on biologically renewable raw materials, with a rubber regenerated compound in the mixture 4(E), makes it possible to greatly reduce the loss factor tan δ (10%) as a measure of the rolling resistance. This effect was by no means to be expected from the individual measures as shown by mixtures 2(V) (only addition of the special terpene resin) and 3(V) (only addition of the rubber regenerated material). The same applies to the tan δ max- value. Another indicator of the unexpectedly good rolling resistance is rebound at 70°C. At the same time, there is a high level of high speed tearing energy in blend 4(E). The resistance of the vulcanized mixture to cuts and fractures is therefore high and high structural durability is provided.References included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2012 108 096 A1 [0005, 0039]WO 99 / 09036

[0048] WO 2008 / 083241 A1

[0048] WO 2008 / 083242 A1

[0048] WO 2008 / 083243 A1

[0048] WO 2008 / 083244 A1

[0048] US 20080161477 A1

[0048] EP 2 114 961 B1

[0048] WO 2010 / 049216 A2

[0057]

Claims

Sulfur-crosslinkable rubber mixture, in particular for the tread of vehicle tires, comprising at least the following constituents: - at least one diene rubber, - 5 to 70 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one terpene resin, - 5 to 80 phr of at least one rubber regenerate, and - 40 to 350 phr of at least one filler.Sulfur-crosslinkable rubber mixture according to Claim 1, characterized in that it comprises 10 to 60 phr, preferably 20 to 50 phr, of at least one terpene resin.Sulfur-crosslinkable rubber mixture according to Claim 1 or 2, characterized in that the at least one terpene resin has an average molecular weight M w by GPC of 800 to 1500 g / mol.Sulfur-crosslinkable rubber mixture according to at least one of the preceding claims, characterized in that the at least one terpene resin has a softening point of 100 to 140°C, preferably 110 to 130°C.Sulfur-crosslinkable rubber mixture according to at least one of the preceding claims, characterized in that the at least one terpene resin has a glass transition temperature Tg of from 50 to 100°C, preferably from 50 to 80°C.Sulfur-crosslinkable rubber mixture of at least one of the preceding claims, characterized in that more than 95% of the at least one terpene resin is based on biologically renewable raw materials.Sulfur-crosslinkable rubber mixture according to Claim 6, characterized in that the at least one terpene resin is 100% based on biologically renewable raw materials.Sulfur-crosslinkable rubber mixture according to Claim 6 or 7, characterized in that the at least one terpene resin is not based on limonene.Sulfur-crosslinkable rubber mixture according to at least one of Claims 6 to 8, characterized in that the at least one terpene resin is based on α- and β-pinene.Sulfur-crosslinkable rubber mixture according to at least one of the preceding claims, characterized in that it comprises 5 to 40 phr of the at least one rubber regenerated material.Sulfur-crosslinkable rubber mixture according to at least one of the preceding claims, characterized in that the at least one rubber regenerated material has been produced from a rubber material mixture in an internal mixer by means of at least one regenerating agent selected from the group consisting of dithiophosphoryl polysulfides and silanes having a polysulfane group, the rubber material mixture consisting of at least 50% by weight of comminuted tread strips of truck radial tires and / or bus radial tires.Sulfur-crosslinkable rubber mixture according to Claim 11, characterized in that the regenerating agent is selected from bis(O,O-2-ethylhexylthiophosphoryl) polysulfide and / or (Bis(triethoxysilyl)propyltetrasulfan (TESPT)).Sulfur-crosslinkable rubber mixture according to Claim 11 or 12, characterized in that the rubber material mixture consists of at least 70% by weight of comminuted tread strips of truck radial tyres and / or bus radial tyres.Sulfur-crosslinkable rubber mixture according to at least one of the preceding claims, characterized in that it comprises from 20 to 200 phr of silica as filler.Pneumatic vehicle tyre according to Claim having a tread, the part of which at least coming into contact with the road surface consists of a rubber mixture vulcanized with sulphur according to one of Claims 1 to 14.