Vulcanized composition based on a sulfur-crosslinkable rubber compound, the use of which in vehicle tires containing the composition

Abstract

Vulcanized composition based on the vulcanization of a sulfur-crosslinkable rubber compound containing at least the following components: - 5 to 95 phr of at least one styrene-butadiene rubber, which is functionalized at least with silane sulfide groups and whose styrene content is 0 to 12 wt.-%, wherein at 0 wt.% styrene a butadiene rubber is present, and which in the unvulcanized state has a glass transition temperature (T g ) according to DSC from -75 to -120 °C, and - 5 to 95 phr of at least one solution-polymerized styrene-butadiene rubber which, in the unvulcanized state, has a glass transition temperature (T g ) according to DSC ranges from -45 to -74 °C, and - 20 to 300 phr of at least one filler.

Description

[0001] The invention relates to a vulcanized composition based on the vulcanization of a sulfur-crosslinkable rubber mixture, in particular for vehicle tires, belts, straps and hoses, and to a vehicle tire.

[0002] The rubber composition of the tread largely determines the driving characteristics of a tire, especially a pneumatic vehicle tire. Likewise, the rubber compounds used in belts, hoses, and straps, especially in areas subject to high mechanical stress, are largely responsible for the stability and durability of these rubber products. Therefore, very stringent requirements are placed on these rubber compounds for pneumatic vehicle tires, belts, and hoses. By partially or completely replacing the carbon black filler with silica in rubber compounds, the driving characteristics of a tire have been brought to a higher level in recent years. However, the well-known conflicting objectives of opposing tire properties still exist, even with tread compounds containing silica. For example, an improvement in wet grip and dry braking generally still results in a deterioration in rolling resistance, winter performance, and abrasion behavior. These properties are also an important quality criterion for technical rubber products such as belts, straps, and hoses.

[0003] Particularly with vehicle tires, numerous attempts have been made to positively influence tire properties by varying the polymer components, fillers, and other additives, especially in the tread compound. The focus here is primarily on rolling resistance and abrasion. It must be considered that an improvement in one tire property often results in a deterioration in another. For example, in a given compound system, there are various known ways to optimize rolling resistance. Worth mentioning here are the reduction of the filler level, the change of the polymer system and the lowering of the glass transition temperature T g of the rubber compound. All of the measures mentioned lead to a deterioration of the abrasion properties and / or wet grip properties and / or tear properties of the given compound.

[0004] In this document, the term vehicle tires refers to pneumatic vehicle tires, solid rubber tires and two-wheel tires.

[0005] In particular, the influence of the glass transition temperature of the rubber compound used by the choice of suitable polymer systems is widely discussed in the specialist world.

[0006] It is known that, even if the components of two rubber compounds are otherwise identical, their glass transition temperature is determined by the glass transition temperature of the polymer(s) used. The higher the glass transition temperature of a polymer, the higher the glass transition temperature of the rubber compound and the worse the rolling resistance behavior of the rubber compound. Good indicators of the rolling resistance behavior of rubber compounds are the rebound resilience at 60 to 70 °C and the hysteresis loss values, expressed as tan δ at 60 to 70 °C.

[0007] It is well known in the art that 1,4-polybutadiene rubber has a very low glass transition temperature of approximately -105 °C, making it suitable for improving the rolling resistance behavior of rubber compounds. However, it is also known that this significantly impairs the wet grip behavior of the rubber compound. In order to influence tire properties such as abrasion, wet skid behavior and rolling resistance, it is also known to use various styrene-butadiene copolymers with different styrene and vinyl contents and with different modifications for the rubber compounds, whereby the described problem of conflicting objectives also arises here.

[0008] From WO 2009007167 A1 it is known to use two different polymers with different glass transition temperatures to improve the wet grip. Also to improve wet grip, EP 065982 A1 uses 20 to 80 phr of diene rubber, specifically natural rubber, and 80 to 20 phr of styrene-butadiene copolymer with a glass transition temperature between -50°C and -25°C.

[0009] DE 698 02 245 T2, in turn, describes a pneumatic tire with a sulfur-vulcanizable composition characterized by 50 to 90 phr of a rubber with a glass transition temperature in the range of -80°C to -110°C, 10 to 50 phr of at least one rubber with a glass transition temperature in the range of -79°C to +20°C, and 15 to 50 phr of a coumarone-indene resin. This mixture exhibits improved laboratory properties, which correlate with improved tire wear while simultaneously improving grip and handling.

[0010] However, the improvement in grip behavior due to a larger hysteresis loss, i.e. larger tan δ at 0°C, is known to be accompanied by a deterioration in the rolling resistance properties, i.e. the damping during driving, which is evident, for example, in DE 698 02 245 T2 from the simultaneous increase in tan δ at 60 °C in ESBR and BR-containing rubber compounds.

[0011] In order to optimize the rolling resistance behavior or to optimize various other properties of rubber compounds relevant for use in tires without impairing the rolling resistance behavior, it is known to functionalize the diene rubber used in such a way that it binds to the filler(s). EP 1963110 B1, for example, discloses silane sulfide-modified polymers with a glass transition temperature of -23 to -28 °C, which achieve low values ​​for the loss factor tan delta (tan δ) at 60 °C in a rubber mixture with otherwise well-balanced other properties.

[0012] WO 2015 / 043902 A1 discloses rubber mixtures each containing 90 phr of a modified styrene-butadiene rubber, whose individual glass transition temperatures are -83°C and -94°C, respectively, and whose individual styrene content is less than 12 wt.%.

[0013] US 2012 / 0123018 A1 discloses specific rubber mixtures with at least one alkoxysilane-modified styrene-butadiene rubber, wherein the rubbers have a glass transition temperature of -27°C or -28.9°C.

[0014] Based on the prior art, the invention is based on the object of providing a vulcanized composition based on the vulcanization of a sulfur-crosslinkable rubber mixture, in particular for vehicle tires, belts, straps and hoses, which is characterized by a further improvement in terms of handling indicators, wherein the other physical properties are to remain at the same level or, in particular, the conflicting objectives of rolling resistance and / or abrasion behavior are to be further optimized.

[0015] This object is achieved by a vulcanized composition based on the vulcanization of a sulfur-curable rubber mixture containing at least the following components: - 5 to 95 phr of at least one styrene-butadiene rubber which is functionalized with at least silane sulfide groups and whose styrene content is 0 to 12 wt. %, wherein at 0 wt. % styrene a butadiene rubber is present, and which in the unvulcanized state has a glass transition temperature (T g ) according to DSC from -75 to -120 °C, and - 5 to 95 phr of at least one solution-polymerized styrene-butadiene rubber which, in the unvulcanized state, has a glass transition temperature (T g ) according to DSC from -45 to -74 °C, and - 20 to 300 phr of at least one filler.

[0016] Surprisingly, it was found that the combination of the styrene-butadiene rubbers with the above-mentioned features and 20 to 300 phr of a filler in the rubber mixture used according to the invention is characterized by an optimization of the physical properties, such as in particular the rolling resistance and / or abrasion behavior as well as the handling indicators. At the same time, the other tire properties remain at an almost identical level or are even improved, with the tear properties and / or dry braking performance and / or winter properties of the rubber compound in particular remaining at an almost identical level or even being improved.

[0017] In particular, it was found that an exchange of 1,4-polybutadiene rubber with a glass transition temperature of approximately -105 °C against the above-described styrene-butadiene rubber functionalized with silane sulfide groups with a nearly identical glass transition temperature is possible, whereby the handling behavior is surprisingly improved and, in addition, an optimization with regard to the conflicting objectives of rolling resistance and wet grip of the rubber compound is achieved.

[0018] It has been shown that the styrene-butadiene rubbers described above interact in a synergistic manner, resulting in surprising improvements, particularly with regard to handling behavior and the conflicting objectives of rolling resistance and wet grip.

[0019] The term phr (parts per hundred parts of rubber by weight) used in this document is the standard quantity used in the rubber industry for compound formulations. The dosage of the parts by weight of the individual substances in this document is based on 100 parts by weight of the total mass of all high-molecular-weight and therefore solid rubbers present in the compound.

[0020] It is essential to the invention that the functionalized styrene-butadiene rubber used in the rubber mixture with a glass transition temperature of -75 to -120 °C is functionalized at least with silane sulfide groups. In the context of the present application, functionalized with silane sulfide groups means that the rubber carries several of these groups along the polymer chain and / or at least one silane sulfide group at the chain end and / or optionally at the chain beginning of each polymer chain. It is also conceivable that not all polymer chains contain a silane sulfide group. The weight fraction of functionalized polymer chains is preferably 30 to 100 wt. %, more preferably 50 to 100 wt. %, and most preferably 70 to 100 wt. %. The polymer chains are preferably functionalized at their chain end with at least one silane sulfide group.

[0021] It is also conceivable that the styrene-butadiene rubber carries additional functional groups in addition to the described silane sulfide functionalization, such as hydroxyl groups in particular. The functionalized styrene-butadiene rubber is preferably produced by anionic polymerization. In this process, the living anionic polymer chains react with one or more modifier compounds, thereby attaching the functional group(s).

[0022] In the context of the present invention, a silane sulfide group refers to an organic radical which contains at least one sulfur atom and at least one substituted silyl group -SiR3.

[0023] It is essential to the invention that the silane sulfide groups contain one or more sulfur atoms.

[0024] According to a preferred embodiment of the invention, the functionalized styrene-butadiene rubber has been formed by reaction of the living polymer chains during anionic polymerization with a silane sulfide modifier according to formula I): (RO) x (R) y Si-R'-S-SiR3 I) where the radicals R are independently C1-C 16 -alkyl or -benzyl groups; and R'' is a C1-C4-alkyl group; and R' is selected from C6-C 18 -aryl, C7-C 50 -Alkylaryl, C1-C 50 -alkyl and C2-C 50 -Dialkyl ethers (ie -alkyl-O-alkyl-), wherein each group is optionally substituted with one or more groups selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, C6-C 12 -aryl, C7-C 16 -Alkylaryl, di(C1-C7-hydrocarbyl)amino, bis(tri(C1-C 12 -Alkyl)silyl)amino, tris(C1-C7-hydrocarbyl)silyl and C1-C 12 -thioalkyl; and x is an integer selected from the numbers 1, 2 and 3; and y is an integer selected from the numbers 0, 1, and 2; and x + y = 3.

[0025] It is assumed that the reaction of the anionic polymer chains with the silane sulfide modifier according to formula (I) results in a modified polymer according to formula (II): (D) z (RO) x (R) y Si-R'-S-SiR3 (II) where D is an elastic polymer; and x is an integer selected from the numbers 0, 1, and 2; and y is an integer selected from the numbers 0, 1, and 2; and z is an integer selected from the numbers 1, 2, and 3; and x + y + z = 3; and R, R'' and R' are defined according to formula (I).

[0026] Such a functionalized styrene-butadiene rubber is functionalized with silane sulfide groups, as can be seen in formula II).

[0027] It is further believed that the polymer, upon contact with moisture, at least partially yields a modified polymer according to formula (III): (D) z (HO) x (R) y Si-R'-S-SiR3 (III) where D is an elastic polymer; and x is an integer selected from the numbers 0, 1 and 2; and y is an integer selected from the numbers 0, 1 and 2; and z is an integer selected from the numbers 1, 2 and 3; and x + y + z = 3; and R and R' are defined according to formula (I).

[0028] According to a preferred embodiment of the invention, in formula (I) each R is independently selected from C1-C5 alkyl groups and R' is a C1-C5 alkyl group.

[0029] According to a further preferred embodiment of the invention, the functionalized styrene-butadiene rubber is produced by reacting the living polymer chains during anionic polymerization with at least one silane sulfide modifier according to formulas (1) and (2) and at least one silane sulfide modifier according to formulas (3), (4), (5) and (6): (R 1 O)3Si-R4 -S-SiR 3 3 (1) (R 13 O)3Si-R 9 -N(SiR 10 R 11 R 12 )2 (2) (R 1 O) x (R 2 ) y Si-R 4 -S-SiR 3 3 (3) (R 13 O) p (R 14 ) q Si-R 9 -N(SiR 10 R 11 R 12 )2 (4) where R 2 , R 3 , R 10 , R 11 , R 12 , R 14 , R 16 , R 17 and R 18 are independently selected from C1-C 16 -Alkyl and -benzyl groups, and where the alkyl groups for the radicals R 10 , R 11 and R 12 and for R 16 , R 17 and R 18 in the form of a ring containing two silicon atoms and nitrogen (N) can be bonded together; and R 1 and R 13are independently selected from C1-C4 alkyl groups; and R 4 , R 9 and R 15 are independently selected from C6-C 18 -aryl, C7-C 50 -Alkylaryl, C1-C 50 -alkyl and C2-C 50 -dialkyl ether (i.e. -alkyl-O-alkyl-), wherein each group is optionally substituted with one or more groups selected from the group consisting of C1-C4 alkyl, C1-C4 alkoxy, C6-C 12 -aryl, C7-C 16 -Alkylaryl, di(C1-C7-hydrocarbyl)amino, bis(tri(C1-C 12 -Alkyl)silyl)amino, tris(C1-C7-hydrocarbyl)silyl and C1-C 12 -thioalkyl; and R 5 , R 6 and R 7 are independently selected from hydrogen (-H), C1-C 16 -alkyl and C6-C 12 -aryl, and R 8 is selected from C1-C 16 -alkyl and C6-C 12 -aryl; and R 19 , R20 and R 21 are independently selected from hydrogen and C1-C 16 -alkyl; and x and p are each an integer selected from the numbers 1 and 2; and y and q are each an integer selected from the numbers 1 and 2; and x + y = 3; and p + q = 3.

[0030] According to a particularly preferred embodiment of the invention, the functionalized styrene-butadiene rubber is formed by reaction of the living polymer chains during anionic polymerization with at least one silane sulfide modifier according to formula IV): (MeO)2(Me)Si-(CH2)2-S-SiMe2C(Me)3 IV)

[0031] The compound according to formula IV) is an example of the silane sulfide modifier according to formula (3).

[0032] With such a modified styrene-butadiene rubber, particularly high improvements are achieved with regard to the handling behavior of the vulcanized composition according to the invention, which is based on the vulcanization of the rubber mixture.

[0033] According to a further particularly preferred embodiment of the invention, the functionalized styrene-butadiene rubber is produced by reaction of the living polymer chains during anionic polymerization with a silane sulfide modifier according to formula IV) and formula V): (MeO)2(Me)Si-(CH2)2-S-SiMe2C(Me)3 IV) (MeO)3Si-(CH2)2-S-SiMe2C(Me)3V)

[0034] The compound according to formula (V) is an example of the silane sulfide modifier according to formula (1).

[0035] With such a modified styrene-butadiene rubber, particularly high improvements are achieved with regard to the conflict of objectives between rolling resistance and wet grip behavior and the handling behavior of the vulcanized composition according to the invention, which is based on the vulcanization of the rubber mixture.

[0036] The silane sulfide-functionalized styrene-butadiene rubber mentioned has a glass transition temperature of -75°C to -120°C (minus 75 to minus 120°C) in the unvulcanized state, preferably -75 to -110°C, particularly preferably -80 to -110°C, and most particularly preferably -80 to -100°C, and can thus be regarded as a styrene-butadiene rubber with a comparatively low glass transition temperature. Thus, in the rubber mixture of the vulcanized composition according to the invention, this styrene-butadiene rubber replaces known diene rubbers with a low glass transition temperature, in particular butadiene rubber (=BR, polybutadiene), while simultaneously improving handling behavior.

[0037] Furthermore, it is essential to the invention that the functionalized styrene-butadiene rubber used in the rubber mixture has a T gfrom -75 to -120 °C has a styrene content of 0 to 12 wt.%. This means that at 0 wt.% styrene, a butadiene rubber is present.

[0038] According to a preferred embodiment of the invention, the styrene content of the styrene-butadiene rubber (with a T g from -75 to -120 °C) 0 to 2 wt.%, particularly preferably 0 wt.% and is therefore a butadiene rubber.

[0039] According to a further preferred embodiment of the invention, the styrene content of the styrene-butadiene rubber (with a T g from -75 to -120 °C) 0.1 to 12 wt.%, particularly preferably 5 to 12 wt.%, most preferably 9 to 11 wt.%.

[0040] The styrene-butadiene rubber with a T gfrom -75 to -120 °C preferably has a vinyl content based on the butadiene content of 1 to 30 wt.%, preferably 1 to 15 wt.%, particularly preferably 5 to 12 wt.% and very particularly preferably 7 to 12 wt.%, again very particularly preferably 7 to 11 wt.%. This achieves a low glass transition temperature of the polymer.

[0041] The determination of the styrene content and the vinyl content of the butadiene portion of the polymers discussed in the present invention is carried out by means of 13 C-NMR (solvent: deuterochloroform CDCl3; NMR: nuclear magnetic resonance) and comparison with infrared spectrometry (IR; FT-IR spectrometer from Nicolet, KBr window 25 mm diameter x 5 mm, 80 mg sample in 5 mL 1,2-dichlorobenzene). The determination of the glass transition temperature (T g) of the polymers (in particular the functionalized styrene-butadiene rubbers) is carried out using dynamic scanning calorimetry (DSC according to DIN 53765: 1994-03 or ISO 11357-2: 1999-03, calibrated DSC with low-temperature device, calibration according to device type and manufacturer's instructions, sample in an aluminum crucible with an aluminum lid, cooling to temperatures lower than -120 °C at 10 °C / min).

[0042] The above functionalized styrene-butadiene rubber with a T g from -75 to -120 °C preferably has a Mooney viscosity (ML 1 +4, 100 °C according to ASTM D 1646 (2004)) of 20 to 200 Mooney units (MU = mooney units), particularly preferably 25 to 150, most preferably 25 to 100.

[0043] The preferred molecular weight distribution of the functionalized styrene-butadiene rubber with a T gFrom -75 to -120 °C, Mw / Mn is between 1.2 and 3.0. If Mw / Mn is less than 1.2, this results in poor processability of the polymer and the rubber mixture used according to the invention, as well as poor distribution of the components, particularly poor filler dispersion of the rubber mixture. If Mw / Mn is greater than 3.0, the proportion of components with a low molecular weight is too high, resulting in increased hysteresis and thus poor rolling resistance behavior of the rubber mixture.

[0044] The above functionalized styrene-butadiene rubber with a T g from -75 to -120 °C is used in the rubber mixture used according to the invention in amounts of 5 to 95 phr, preferably 20 to 95 phr, particularly preferably 20 to 75, particularly preferably 40 to 75 phr, again very particularly preferably in amounts of 40 to 60 phr.

[0045] The styrene-butadiene rubber used, functionalized with silane sulfide groups, with a T g from -75 to -120 °C has in a preferred embodiment a styrene content of 0 wt.% and a vinyl content of 1 to 15 wt.%, particularly preferably 7 to 12 wt.%.

[0046] The styrene-butadiene rubber used, functionalized with silane sulfide groups, with a T g The polymer can be solution-polymerized or emulsion-polymerized at temperatures from -75 to -120 °C. Preferably, it is solution-polymerized styrene-butadiene rubber S(S)BR with a styrene content of 0 to 12 wt.%.

[0047] The rubber mixture used according to the invention in the vulcanized composition according to the invention additionally contains 5 to 95 phr, preferably 5 to 80 phr, particularly preferably 25 to 80 phr, very particularly preferably 25 to 60 phr, again very particularly preferably 25 to 35 phr of at least one solution-polymerized styrene-butadiene rubber (SSBR) which, in the unvulcanized state, has a glass transition temperature (T g ) according to DSC of -45 to -74 °C, preferably -50 to -74 °C, particularly preferably -60 to -70 °C.

[0048] According to a preferred embodiment of the invention, the styrene content of the solution-polymerized styrene-butadiene rubber (with a T g from -45 to -74 °C) 0.1 to 70 wt.%, particularly preferably 5 to 70 wt.%, very particularly preferably 5 to 20 wt.%, again very particularly preferably 12 to 17 wt.%.

[0049] The styrene-butadiene rubber with a T gfrom -45 to -74 °C preferably has a vinyl content based on the butadiene content of 1 to 70 wt.%, preferably 1 to 50 wt.%, particularly preferably 10 to 50 wt.% and very particularly preferably 25 to 35 wt.%.

[0050] The determination of the styrene content and the vinyl content as well as the glass transition temperature (T g ) of the styrene-butadiene rubber with a T g from -45 to -74 °C is carried out as stated above for the functionalized styrene-butadiene rubber.

[0051] According to a preferred development of the invention, at least one further rubber is contained in the rubber mixture.

[0052] The at least one further rubber is selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or butadiene rubber and / or solution-polymerized styrene-butadiene rubber and / or emulsion-polymerized styrene-butadiene rubber and / or liquid rubbers with a molecular weight Mw of greater than 20,000 g / mol and / or halobutyl rubber and / or polynorbornene and / or isoprene-isobutylene copolymer and / or ethylene-propylene-diene rubber and / or nitrile rubber and / or chloroprene rubber and / or acrylate rubber and / or fluororubber 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.

[0053] In particular, nitrile rubber, hydrogenated acrylonitrile butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber or ethylene-propylene-diene rubber are used in the production of technical rubber articles such as belts, straps and hoses.

[0054] Preferably, the further rubber is at least one diene rubber selected from the group consisting of synthetic polyisoprene and natural polyisoprene (NR) and styrene-butadiene rubber and polybutadiene (BR). The natural polyisoprene and the synthetic polyisoprene can be any type known to the person skilled in the art. Preferably, the additional diene rubber is at least natural polyisoprene. This achieves particularly good processability (extrudability, miscibility, etc.) of the rubber mixture. The styrene-butadiene rubber from the group of additional diene rubbers is, in the context of the present application, another styrene-butadiene rubber known in the prior art and can therefore be used in blends with the styrene-butadiene rubbers essential to the invention.

[0055] According to a further preferred development of the invention, the rubber mixture contains 5 to 40 phr of at least one natural polyisoprene and / or 5 to 40 phr of at least one synthetic polyisoprene, preferably 5 to 30 phr of at least one natural polyisoprene and / or 5 to 30 phr of at least one synthetic polyisoprene, particularly preferably 15 to 25 phr of at least one natural polyisoprene and / or 15 to 25 phr of at least one synthetic polyisoprene.

[0056] According to a preferred embodiment of the invention, the rubber mixture contains 15 to 25 phr of at least one natural and / or synthetic polyisoprene in combination with 40 to 60 phr, again preferably 45 to 55 phr, of the styrene-butadiene rubber functionalized with silane sulfide groups as described above, having a T gfrom -100 to -87 °C, which in this embodiment particularly preferably has a styrene content of 0 to 2 wt.%, most preferably 0 wt.%, and 20 to 40 phr, preferably 25 to 35 phr, of a solution-polymerized styrene-butadiene rubber with a glass transition temperature of -45 °C to -74 °C, preferably -60 to -70 °C. Such a rubber mixture shows, in comparison to a rubber mixture containing the same amount of butadiene rubber with a T g of -105 °C from the state of the art, better handling behavior and improved abrasion resistance.

[0057] According to a further preferred embodiment of the invention, the rubber mixture contains 10 to 70 phr of a styrene-butadiene rubber functionalized with silane sulfide groups and having a T gfrom -75 to -120 °C and 10 to 70 phr of a solution-polymerized styrene-butadiene rubber with a glass transition temperature of -45 to -74 °C, wherein the latter styrene-butadiene rubber with a glass transition temperature of -45 to -74 °C is preferably also functionalized and particularly preferably also functionalized with at least silane sulfide groups and / or hydroxyl groups. Such a combination results in synergistic effects with regard to improving the handling behavior of the rubber compound and optimizing it with regard to rolling resistance and abrasion resistance.

[0058] According to an advantageous development of the invention, it is also conceivable that the rubber mixture contains 10 to 300 phr of at least one hydrocarbon resin made of alpha-methylstyrene and styrene, which shows further synergistic effects in improving the performance level with regard to processability and handling behavior and the conflict of objectives between the indicators for rolling resistance and wet grip. The rubber mixture preferably contains 10 to 200 phr, particularly preferably 10 to 100 phr, very particularly preferably 10 to 50 phr and again very particularly preferably 20 to 40 phr of at least one hydrocarbon resin made of alpha-methylstyrene and styrene.

[0059] It is clear to those skilled in the art that hydrocarbon resins are polymers composed of monomers, with the hydrocarbon resin formally composed of derivatives of the monomers through the linkage of the monomers. However, these hydrocarbon resins are not considered rubbers within the scope of the present invention.

[0060] For the purposes of the present invention, a copolymer is understood to mean a polymer composed of several, i.e., two or more, different monomers. Therefore, for the purposes of the present invention, the hydrocarbon resin can also be, for example, a copolymer of three different monomers.

[0061] The rubber mixture used according to the invention in the vulcanized composition according to the invention contains 20 to 300 phr, preferably 20 to 150 phr, particularly preferably 40 to 150 phr and very particularly preferably 80 to 130 phr of at least one filler. The filler can be any filler known to the person skilled in the art, such as silica and / or carbon black as well as other known polar and / or non-polar fillers.

[0062] The rubber mixture preferably contains at least one silica. The silicas can be those known to those skilled in the art and suitable as fillers for tire rubber compounds. However, it is particularly preferred to use a finely divided, precipitated silica with a nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132) of 35 to 350 m². 2 / g, preferably from 35 to 260 m 2 / g, particularly preferably from 100 to 260 m 2 / g and most preferably from 130 to 235 m 2 / g, and a CTAB surface area (according to ASTM D 3765) of 30 to 400 m 2 / g, preferably from 30 to 255 m 2 / g, particularly preferably from 100 to 255 m 2 / g and most preferably from 125 to 230 m 2 / g. Such silicas, for example, lead to particularly good physical properties of the vulcanizates in rubber compounds for tire treads. Furthermore, they can offer advantages in compound processing by reducing mixing times while maintaining consistent product properties, leading to improved productivity. Thus, both Ultrasil® VN3 (trade name) from Evonik and highly dispersible silicas, so-called HD silicas (e.g., Zeosil® 1165 MP from Rhodia), can be used as silicas.

[0063] Preferably, a coupling agent in the form of a silane or an organosilicon compound is used. One or more different silane coupling agents can be used in combination. The rubber compound can thus contain a mixture of different silanes. The silane coupling agents react with the surface silanol groups of the silica or other polar groups during the mixing of the rubber or rubber mixture (in situ) or even before the addition of the filler to the rubber as a pretreatment (premodification). Silane coupling agents that can be used are all silane coupling agents known to the person skilled in the art for use in rubber mixtures. 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 -S x - (with x = 2 to 8).

[0064] 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).

[0065] Preferably, a silane mixture is used which contains 40 to 100 wt.% disulfides, particularly preferably 55 to 85 wt.% disulfides and very particularly preferably 60 to 80 wt.% disulfides. 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. The amount of coupling agent is preferably 0.1 to 20 phr, particularly preferably 1 to 15 phr.

[0066] According to a preferred embodiment of the invention, the rubber mixture contains 80 to 110 phr of silica. This results in particularly good physical properties, in particular a good level of abrasion resistance, the trade-off between rolling resistance and wet grip, and handling behavior.

[0067] According to a preferred development of the invention, preferably 2 to 20 phr, particularly preferably 10 to 20 phr, of carbon black are additionally contained in the rubber mixture.

[0068] Suitable carbon blacks include all types of carbon black known to the person skilled in the art. In one embodiment, the carbon black has an iodine number according to ASTM D 1510, also referred to as the iodine adsorption number, between 30 g / kg and 250 g / kg, preferably 30 to 180 g / kg, more preferably 40 to 180 g / kg, and most preferably 40 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, more preferably 115 to 200 ml / 100 g. The DBP number according to ASTM D 2414 determines the specific absorption volume of a carbon black or a light filler using dibutyl phthalate. The use of such a type of carbon black in the rubber compound, especially for vehicle tires, ensures the best possible compromise between abrasion resistance and heat build-up, which in turn influences the ecologically relevant rolling resistance.

[0069] It is preferred if only one type of carbon black is used in the respective rubber mixture, but different types of carbon black can also be mixed into the rubber mixture.

[0070] Furthermore, it is conceivable that the rubber mixture contains carbon nanotubes (CNTs) including discrete CNTs, so-called hollow carbon fibers (HCFs) and modified CNTs containing one or more functional groups, such as hydroxyl, carboxy and carbonyl groups). Graphite and graphene as well as so-called “carbon-silica dual-phase fillers” are also conceivable as fillers. The rubber mixture may also contain other polar fillers such as aluminosilicates, chalk, starch, magnesium oxide, titanium dioxide or rubber gels.

[0071] The rubber mixture may also contain 0 to 70 phr, preferably 0.1 to 60 phr, preferably 0.1 to 50 phr, of at least one plasticizer. These include all plasticizers known to those skilled in the art, such as aromatic, naphthenic, or paraffinic mineral oil plasticizers, such as MES (mild extraction solvate) or TDAE (treated distillate aromatic extract), or rubber-to-liquid oils (RTL) or biomass-to-liquid oils (BTL), or factitious resins or liquid polymers (such as liquid BR) whose average molecular weight (determined by GPC = gel permeation chromatography, based on BS ISO 11344:2004) is between 500 and 20,000 g / mol. If liquid polymers are used as plasticizers in the rubber mixture, they are not included as rubber in the calculation of the composition of the polymer matrix. When using mineral oil, this is preferably selected from the group consisting of DAE (Distilled Aromatic Extracts) and / or RAE (Residual Aromatic Extract) and / or TDAE (Treated Distilled Aromatic Extracts) and / or MES (Mild Extracted Solvents) and / or naphthenic oils.

[0072] Furthermore, the rubber compound 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 and fatty acids (e.g. stearic acid), c) waxes, (d) resins, in particular adhesive resins, other than the above-mentioned hydrocarbon resin made from alpha-methylstyrene and styrene. e) mastication aids such as 2,2'-dibenzamidodiphenyl disulfide (DBD) and f) processing aids such as fatty acid salts, such as zinc soaps, and fatty acid esters and their derivatives.

[0073] Particularly when the rubber compound is used for the internal components of a tire or a technical rubber article, which have direct contact with existing reinforcements, a suitable adhesive system, often in the form of adhesive resins, is usually added to the rubber compound.

[0074] The proportion of the total amount of other additives is 3 to 150 phr, preferably 3 to 100 phr and particularly preferably 5 to 80 phr. The total amount of other additives also contains 0.1 to 10 phr, preferably 0.2 to 8 phr, particularly preferably 0.2 to 4 phr, of zinc oxide (ZnO). This can be any type of zinc oxide known to the person skilled in the art, such as ZnO granules or powder. The zinc oxide commonly used usually has a BET surface area of ​​less than 10 m 2 / g. However, so-called nano-zinc oxide with a BET surface area of ​​10 to 60 m 2 / g can be used.

[0075] Vulcanization is carried out in the presence of sulfur or sulfur donors with the aid of 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 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 using a sulfenamide accelerator selected from the group consisting of 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).

[0076] Other network-forming systems, such as those available under the trade names Vulkuren®, Duralink®, or Perkalink®, or network-forming systems as described in WO 2010 / 049261 A2, can also be used in the rubber compound. This system contains a vulcanizing agent that crosslinks with a functionality greater than four and at least one vulcanization accelerator. The vulcanizing agent that crosslinks with a functionality greater than four has, for example, the general formula A): G[C a H 2a -CH2-S b Y] c A) wherein G is a polyvalent cyclic hydrocarbon group and / or a polyvalent heterohydrocarbon group and / or a polyvalent siloxane group containing 1 to 100 atoms; wherein each Y is independently selected from a rubber-active group containing sulfur-containing functionalities; and wherein a, b, and c are integers each of which independently includes: a is 0 to 6; b is 0 to 8; and c is 3 to 5. The rubber-active group is preferably selected from a thiosulfonate group, a dithiocarbamate group, a thiocarbonyl group, a mercapto group, a hydrocarbon group, and a sodium thiosulfonate group (Bunte salt group). This results in very good abrasion and tear properties of the rubber mixture.

[0077] In the context of the present invention, sulfur and sulfur donors, including sulfur-donating silanes such as TESPT, and vulcanization accelerators as described above and vulcanizing agents which crosslink with a functionality greater than four, as described in WO 2010 / 049261 A2, such as a vulcanizing agent of the formula A), as well as the above-mentioned systems Vulkuren®, Duralink® and Perkalink® are conceptually summarized as vulcanizing agents. The rubber mixture preferably contains at least one vulcanizing agent selected from the group consisting of sulfur and / or sulfur donors and / or vulcanization accelerators and / or vulcanizing agents that crosslink with a functionality greater than four. This allows vulcanizates according to the invention, particularly for use in vehicle tires, to be produced from the rubber mixture used according to the invention.

[0078] The rubber mixture preferably contains at least one vulcanizing agent selected from the group consisting of sulfur and / or sulfur donors and / or vulcanization accelerators and / or vulcanizing agents that crosslink with a functionality greater than four. This allows vulcanizates according to the invention, particularly for use in vehicle tires, to be produced from the rubber mixture used according to the invention.

[0079] In addition, vulcanization retarders may be present in the rubber compound.

[0080] According to an advantageous development of the invention, several accelerators are used. Preferably, a sulfenamide accelerator, particularly preferably CBS, is used in combination with the guanidine accelerator DPG (diphenylguanidine). The amount of DPG is 0 to 5 phr, preferably 0.1 to 3 phr, particularly preferably 0.5 to 2.5 phr, and most preferably 1 to 2.5 phr.

[0081] A further object of the present invention is to provide a vehicle tire which is characterized by improved handling behavior and / or an improvement in rolling resistance and abrasion behavior (abrasion resistance).

[0082] This object is achieved by the vehicle tire containing the vulcanized composition according to the invention as described above in at least one component. All the above-mentioned statements regarding the components and their features apply. The component is preferably a tread and / or a sidewall, particularly preferably a tread. As is known to those skilled in the art, the tread contributes a relatively high proportion to the overall rolling resistance and significantly to the tire's wet grip performance. The vehicle tire is preferably a pneumatic vehicle tire.

[0083] The invention is further based on the object of optimizing the physical properties of vehicle tires without significantly negatively affecting other properties relevant for the respective application. This object is achieved by using the above-described vulcanized composition for the production of vehicle tires, in particular for the production of a tire's tread and / or a tire body compound. This text also relates to the production of technical rubber articles, such as belts, straps, and hoses. The body compound refers to the rubber compounds used for the inner components of a tire. Internal tire components include the squeegee, sidewall, inner liner (inner layer), apex, belt, shoulder, belt tread, carcass, bead reinforcement, bead tread, flange tread, and bandage.

[0084] The rubber compound is manufactured according to the process commonly used in the rubber industry, in which a base compound containing all components except the vulcanization system (sulfur and vulcanization-influencing substances) is first produced in one or more mixing stages. The final compound is created by adding the vulcanization system in a final mixing stage. The final compound is further processed, for example, by extrusion, and molded into the appropriate shape.

[0085] For use in vehicle tires, the compound is preferably formed into a tread and applied during the production of the green tire as usual. However, the tread can also be wound onto a green tire in the form of a narrow strip of rubber compound. For split treads (upper part: cap and lower part: base), the rubber compound can be used for both the cap and the base. The rubber compound for use as a body compound in vehicle tires is produced as already described for the tread. The difference lies in the shaping after the extrusion process. The resulting shapes of the rubber compound for one or more different body compounds are then used to construct a green tire. For use of the rubber compound in belts and straps, particularly conveyor belts, the extruded compound is formed into the appropriate shape and often provided with strength members, e.g. synthetic fibers or steel cords, either during or after the process. This usually results in a multi-layer structure consisting of one or more layers of rubber compound, one or more layers of the same and / or different strength members, and one or more further layers of the same and / or a different rubber compound.

[0086] For use in hoses, so-called sulfur crosslinking is often preferred, rather than peroxide crosslinking, which is not according to the invention. The hoses are manufactured analogously to the process described in the Handbook of Rubber Technology, Dr. Gupta Verlag, 2001, Chapter 13.4.

[0087] The invention will now be explained in more detail with reference to comparative and exemplary embodiments, which are summarized in Table 1. The mixtures marked with "E" are mixtures for the vulcanized compositions according to the invention, while the mixtures marked with "V" are comparison mixtures. For all compound examples included in the table, the quantities given are parts by weight based on 100 parts by weight of total rubber (phr).

[0088] The compounds were prepared under standard conditions in three stages in a laboratory tangential mixer. Test specimens were prepared from all compounds by optimal vulcanization under pressure at 160 °C, and these specimens were used to determine material properties typical for the rubber industry. The following test procedures were used for the specimen tests described above: • Shore A hardness (unit Shore A, abbreviated ShA) at room temperature (RT) and 70 °C according to DIN 53 505 • Rebound resilience (abbreviated rebound) at 70°C according to DIN 53 512 • Stress value at 50%, 100%, 200% and 300% elongation (module 50, modulus 100, modulus 200 or modulus 300) at room temperature according to DIN 53 504 • Average dynamic storage modulus (E 'mittel ) from dynamic-mechanical measurement at 55 °C according to DIN 53 513, strain sweep • Abrasion at room temperature according to DIN 53 516 or DIN / ISO 4649 Table 1 Components Unit V1 V2 V3 V4 V5 E1 NR phr 20 20 20 20 20 20 BR a) phr 50 - 50 - 50 - SSBR b) phr 30 30 - - - - SSBR c) phr - - 30 30 - - SSBR d) phr - - - - 30 30 SBR e) phr - 50 - 50 - 50 Silica f) phr 85 85 85 85 85 85 Soot N339 phr 14 14 14 14 14 14 Powerful g) phr 6,0 6,0 6,0 6,0 6,0 6,0 TDAE phr 48 48 48 48 48 48 Anti-aging protection h) phr 4,0 4,0 4,0 4,0 4,0 4,0 ZnO phr 3,0 3,0 3,0 3,0 3,0 3,0 Stearic acid phr 2,0 2,0 2,0 2,0 2,0 2,0 Process aids i) phr 5,0 5,0 5,0 5,0 5,0 5,0 accelerator j) phr 3,8 3,8 3,8 3,8 3,8 3,8 sulfur phr 2,1 2,1 2,1 2,1 2,1 2,1 Characteristics Shore hardness at RT Shore A 61 61 62 62 61 65 Shore hardness at 70 °C Shore A 56 57 57 57 56 60 Rebound 70 °C % 46 50 44 48 48 50 Module 50 MPa 1,1 1,1 1,1 1,0 1,0 1,3 Module 100 MPa 1,8 1,9 1,7 1,9 1,7 2,1 Module 200 MPa 3,7 4,1 3,4 4,0 3,5 4,4 Module 300 MPa 6,0 6,9 5,5 6,8 5,7 7,4 E' mittel % 7,3 7,8 7,7 8,0 7,7 9,6 DIN abrasion mm 3 94 93 108 96 78 74

[0089] Substances used from Table 1: a) BR: Polybutadiene, high-cis, Nd-catalyzed butadiene rubber, unfunctionalized, T g = -105 °C, Europrene ® NEOCIS BR 40, Polimeri b) SSBR: Nipol NS 616, Zeon Corporation, T g = -25 °C c) SSBR: SPRINTAN SLR-4601, Styron Deutschland GmbH, T g = -25 °C d) SSBR: SPRINTAN SLR-3402, Styron Deutschland GmbH, T g = -64 °C e) SBR: Styrene content = 0 wt.%, therefore butadiene rubber; vinyl content = 8 wt.%; T g = - 94 °C; modified with (MeO)2(Me)Si-(CH2)2-S-SiMe2C(Me)3 IV) and (MeO)3Si-(CH2)2-S-SiMe2C(Me)3V) f) Silica: ULTRASIL® VN3, Evonik g) Silane JH-S75, Jingzhou Jianghan Fine Chemical h) Anti-aging agent: Ozone protection wax + 6PPD i) Processing aids: fatty acid esters and zinc soaps j) Accelerators: DPG (diphenylguanidine) and CBS (N-cyclohexyl-2-benzothiazolesufenamide) and MBT

[0090] As can be seen from Table 1, in the rubber mixture E1 for the vulcanized composition according to the invention, a surprising synergistic interaction of the silane sulfide-functionalized butadiene rubber (SBR with 0 wt.% styrene) with the SSBR with a glass transition temperature of -45 to -74 °C is shown with regard to the handling behavior (larger E' and larger moduli 50 to 300 as well as higher hardnesses) as well as the conflict of objectives between rolling resistance (larger or at least equal rebound elasticities at 70 °C) and abrasion behavior (lower material removal). Thus, the rubber compound makes it possible, particularly through its use in the tread, to further improve the rolling resistance and handling behavior as well as the abrasion resistance of vehicle tires based on the state of the art.

Claims

[1] Vulcanised composition based on the vulcanisation of a sulphur-curable rubber mixture containing at least the following components: - 5 to 95 phr of at least one styrene-butadiene rubber which is functionalized with at least silane sulfide groups and whose styrene content is 0 to 12 wt. %, wherein at 0 wt. % styrene a butadiene rubber is present, and which in the unvulcanized state has a glass transition temperature (T g ) according to DSC from -75 to -120 °C, and - 5 to 95 phr of at least one solution-polymerized styrene-butadiene rubber which, in the unvulcanized state, has a glass transition temperature (T g ) according to DSC from -45 to -74 °C, and - 20 to 300 phr of at least one filler. [2] Vulcanized composition according to claim 1, characterized bythat the sulfur-curable rubber compound contains 5 to 30 phr of natural polyisoprene and / or 5 to 30 phr of synthetic polyisoprene. [3] Vulcanized composition according to any one of the preceding claims, characterized by that the styrene-butadiene rubber functionalized with silane sulfide groups has a vinyl content of 7 to 12 wt.%. [4] Vulcanized composition according to any one of the preceding claims, characterized by that the styrene-butadiene rubber functionalized with silane sulfide groups has a styrene content of 0 wt.%. [5] Vulcanized composition according to any one of the preceding claims, characterized by that the sulfur-curable rubber mixture contains 10 to 70 phr of a styrene-butadiene rubber functionalized with silane sulfide groups with a T gfrom -75 to -120 °C and 10 to 70 phr of a solution-polymerized styrene-butadiene rubber with a glass transition temperature of -45 to -74 °C. [6] Vulcanized composition according to any one of claims 1 to 4, characterized by that the styrene-butadiene rubber functionalized with silane sulfide groups has a glass transition temperature (T g ) according to DSC from -80 to -110 °C. [7] Vulcanized composition according to any one of the preceding claims, characterized by that the solution-polymerized styrene-butadiene rubber has a glass transition temperature of -60 to -70 °C. [8] Vehicle tires, characterized by that it contains in at least one component a vulcanized composition according to one of the preceding claims. [9] Vehicle tyre according to claim 8, characterized by that the component is a tread and / or a sidewall. [10] Use of a vulcanized composition according to any one of claims 1 to 7 for the manufacture of a vehicle tire.