Crosslinkable rubber mixtures and pneumatic vehicle tires

Abstract

The invention relates to a crosslinkable rubber mixture comprising: a. a diene rubber having an average molecular weight of more than 150,000 g / mol, b. a filler, c. a polymer or oligomer having an average molecular weight Mn of less than 150,000 g / mol, the polymer or oligomer having functional groups interacting with the filler and a glass transition temperature Tg of < -15 °C g d. a polymer or oligomer having an average molecular weight Mn of less than 150,000 g / mol, the polymer or oligomer having functional groups interacting with the filler and a glass transition temperature Tg of > -15 °C g .

Description

TECHNICAL FIELD

[0001] The present application relates to a crosslinkable rubber mixture and to a pneumatic vehicle tire comprising at least one tire component made of rubber and at least partially manufactured from such a rubber mixture. BACKGROUND

[0002] A known way of optimizing the physical properties of vulcanized articles manufactured from rubber mixtures, such as cords, belts and hoses, for example, which form a part of a pneumatic vehicle tire or an industrial rubber article, is to vary the mixture constituents of the rubber mixture. It is generally possible to improve one property of the vulcanized rubber by varying the mixture constituents, while at the same time a deterioration of another property of the vulcanized rubber occurs, so that a compromise exists between these two properties of the vulcanized rubber. In the case of a tread of a pneumatic vehicle tire, such a compromise exists between the rolling resistance, the wet grip properties and the wear resistance.

[0003] Known ways of influencing the rolling resistance, the wet grip properties and the wear resistance of a tread are, for example, the use of styrene-butadiene rubbers having different microstructures or modified styrene-butadiene rubbers in the rubber mixture of the underlayer. In the case of styrene-butadiene rubbers, in particular, the styrene content and the vinyl content are varied, the end groups are modified or coupling or hydrogenation is carried out.

[0004] EP 2 060 604 B1, for example, discloses a rubber mixture which is intended, inter alia, for a tread of a pneumatic vehicle tire, which rubber mixture comprises a filler and a low molecular weight diene rubber having an average molecular weight M W (mass average molecular weight) of 2000 g / mol to 150 000 g / mol and an aromatic vinyl compound content of less than 5%. A tread manufactured from such a rubber mixture is considered to have a low rolling resistance.

[0005] In addition, WO 2018 / 191 187 A1 discloses a rubber mixture which comprises a functionalized resin having a polar linking group. The rubber mixture is used, for example, for the production of hoses, gaskets, belts, shoe soles or tire components, in particular treads or sidewalls.

[0006] The currently known rubber mixtures have not been able to satisfactorily solve the compromise between low rolling resistance, good wet grip properties and high wear resistance present in the treads of pneumatic vehicle tires. SUMMARY

[0007] The problem addressed by the present application is therefore to provide a rubber mixture for a tread of a pneumatic vehicle tire with the aid of which a better solution than is currently available can be achieved in the compromise between rolling resistance, wet grip properties and wear resistance.

[0008] According to the present application, this is achieved by a cross-linkable rubber mixture, which contains

[0009] a) a diene rubber having an average molecular weight of more than 150 000 g / mol,

[0010] b) a filler,

[0011] c) a polymer or oligomer having an average molecular weight Mn of less than 150 000 g / mol, which polymer or oligomer has functional groups interacting with the filler and a glass transition temperature T g ,

[0012] d) a polymer or oligomer having an average molecular weight Mn of less than 150 000 g / mol, which polymer or oligomer has functional groups interacting with the filler and a glass transition temperature T g .

[0013] In such a rubber mixture, the mixture constituents (i.e. components c) and d)) with functional groups interacting with the filler have an increased interaction with the filler and lead to an interface between the polymer or oligomer and the filler. The combination of polymers and / or oligomers interacting with the filler having different glass transition temperatures optimizes the properties of this interface, especially in a way matching the respective application of the rubber mixture. In a test series we have conducted (see below), it has surprisingly been found that a tread or tread portion manufactured from such a rubber mixture can be expected to have advantageous wet grip properties (loss factor tan d at 0°C as wet grip indicator) and low rolling resistance (loss factor tan d at 70°C as rolling resistance indicator) while still having unaltered good abrasion resistance.

[0014] In a preferred embodiment, the rubber mixture comprises silica and / or carbon black as filler.

[0015] In another preferred embodiment, the polymer or oligomer of feature c) is a diene-based polymer or oligomer.

[0016] In another preferred embodiment, the polymer or oligomer of feature c) has a glass transition temperature T g .

[0017] In another preferred embodiment, the polymer or oligomer of feature c) has an average molecular weight Mn(number average molecular weight by gel permeation chromatography) of 500 g / mol to 50 000 g / mol, in particular 1000 g / mol to 20 000 g / mol, more preferably 3000 g / mol to 15 000 g / mol.

[0018] Another preferred embodiment is characterized in that the polymer or oligomer of feature c) has been functionalized with a silyl protecting group.

[0019] It is further preferred that the polymer or oligomer of feature c) is a polybutadiene functionalized with a functional group interacting with the filler.

[0020] It is also preferred that the polymer or oligomer of feature c) and / or the polymer or oligomer of feature d) has been functionalized with a silyl protecting group having the formula IV:

[0021] (R 1 R 2 R 3 )Si- formula IV

[0022] wherein,

[0023] R 1 , R 2 , R 3 are independently selected from the group of linear or branched alkoxy, cycloalkoxy, alkyl, cycloalkyl, aryl or hydroxyl groups having 1 to 20 carbon atoms in each case or hydrogen, and

[0024] wherein the silyl protecting group having the formula IV is attached to the polymer chain of the polymer or oligomer directly or via a bridge, and

[0025] wherein the bridge is formed by a saturated or unsaturated hydrocarbon group which can contain heteroatoms, in particular sulfur and / or nitrogen.

[0026] It is further preferred that the polymer or oligomer of feature d) has been functionalized with a silyl protecting group having the formula V:

[0027] -[Z k -X n -R 4 -(CH2) m -Si(R 5 ) p ] q formula V

[0028] wherein,

[0029] -Z is an aromatic or aliphatic group, optionally having one or more heteroatoms,

[0030] -X is a linking group containing sulfur and / or oxygen and / or nitrogen and / or carbonyl groups.

[0031] -R 4 It is one or more aliphatic groups having 1 to 18 carbon atoms and / or linking groups attached to at least one heteroatom, particularly attached to oxygen, nitrogen or sulfur.

[0032] -R 5 It is a branched or unbranched alkoxy, aryloxy, alkyl or aryl group having 1 to 18 carbon atoms, wherein at least one R 5 It is an alkoxy or aryloxy group having 1 to 18 carbon atoms, a hydrogen atom, or a hydroxyl group, wherein R in the molecule 5 Are they the same or different?

[0033] -q is an integer ≥ 1.

[0034] -k is 0 or 1.

[0035] -n is an integer from 1 to 10.

[0036] -m is an integer from 0 to 10, and

[0037] -p is 1, 2, or 3.

[0038] Further preferably, the polymer or oligomer of feature d) is a resin based on unsaturated aliphatic monomers, unsaturated aliphatic monomers, terpenes, rosin, unsaturated cyclic aromatic monomers, unsaturated alicyclic monomers, unsaturated fatty acids, methacrylates and / or vinyl aromatic monomers.

[0039] Further preferably, the polymer or oligomer of feature d) has an average molecular weight (Mn) of 200 g / mol to 150,000 g / mol, preferably 200 g / mol to 50,000 g / mol, more preferably 200 g / mol to 30,000 g / mol.

[0040] Further preferably, the polymer or oligomer of feature c) and the polymer or oligomer of feature d) are present in a ratio of 1:50 to 50:1, especially 1:10 to 10:1, preferably 1:5 to 5:1, and more preferably 1:3 to 3:1.

[0041] Further preferably, at the glass transition temperature T of the polymer or oligomer of characteristic c), g The glass transition temperature T of the polymer or oligomer with characteristic d) g The measured temperature difference ΔT between them g The temperature should be at least 5°C, and especially at least 10°C.

[0042] It is further preferred that the rubber mixture contains at least one silane coupling agent. The silane coupling agent can also produce an increased interaction of the filler with the polymer or oligomer.

[0043] The present application also relates to a pneumatic vehicle tire comprising at least one tire component composed of rubber, in particular a tread, which is at least partially manufactured from a rubber mixture according to any one of claims 1 to 13. Such a tread has good wet grip properties, low rolling resistance and high wear resistance. In particular, a compromise between these properties, which is otherwise present, is solved in a particularly advantageous manner. DETAILED DESCRIPTION

[0044] Further features, advantages and details of the present application will now be explained in detail with reference to the test series, which comprises working examples of the present application and is summarized in the tables.

[0045] The present application relates to a rubber composition which has a particularly good suitability for the manufacture of tire components or components of tire components, in particular treads or tread layers. In the course of the test series, rubber mixtures were produced and tested for specific vulcanizate properties. The rubber mixtures implemented according to the present application were compared with comparative rubber mixtures (reference rubber mixtures).

[0046] Production of the rubber mixtures:

[0047] The rubber mixtures were produced in multiple stages in a laboratory mixer (300 mL, Brabender Mixer, CW Brabender GmbH & Co. KG, South Hackensack, NJ, US) under customary conditions. During the first mixing stage (base mixing stage), all of the mixture ingredients of the respective rubber mixture were mixed, with the exception of at least some of the mixture ingredients of the crosslinking system, in particular with the exception of sulfur and accelerators. The final rubber mixture (final mixture) was obtained in a further mixing stage (final mixing stage) by mixing in the crosslinking system or mixing in the missing ingredients of the crosslinking system. Table 1 contains the mixing parameters, i.e. the conditions under which the rubber mixtures were produced. A tolerance range of + / - 3°C customary was applied to these temperatures.

[0048] Table 1 : Mixing parameters

[0049]

[0050] Vulcanizate tests:

[0051] All rubber mixtures were used to produce standardized vulcanized test samples (vulcanization conditions: time = 20 min, temperature = 160 °C) with which some typical vulcanized rubber properties were determined. The following vulcanized rubber tests were carried out:

[0052] • Shore A hardness at room temperature (25 °C) by durometer according to DIN ISO 7619-1,

[0053] • Loss factor tan d (tan delta) at 0 °C and 70 °C from temperature-dependent dynamic mechanical measurements by Eplexor according to DIN 53 513 (constant force, 10% compression, ±0.2% strain amplitude, frequency 10 Hz),

[0054] • abrasion test at room temperature (25 °C) according to DIN ISO 4649

[0055] These vulcanized rubber properties allow conclusions to be drawn about the expected properties of a tread made from this rubber mixture or of a radially outermost tread layer made from this rubber mixture which is in contact with the road when driving.

[0056] The Shore A hardness is a measure of the stiffness of the vulcanized rubber in particular.

[0057] The loss factor tan d at 0 °C is used as an indicator of the wet grip of a tire. The greater the loss factor tan d at 0 °C, the better the wet grip properties.

[0058] The loss factor tan d at 70 °C is used as an indicator of the rolling resistance of a tire, a lower loss factor tan d at 70 °C means a lower rolling resistance.

[0059] In the abrasion test, correspondingly standardized test samples are subjected to abrasion and the abrasion (amount of material worn off) is determined in mm 3 . The lower the abrasion value, the higher (better) the abrasion resistance.

[0060] Test series carried out:

[0061] A number of test series were carried out in which the influence of specific mixture components on the above-mentioned vulcanized rubber properties was examined. These specific mixture components include silane coupling agents which have already been used in the rubber mixtures described above and which have been used in the test series described below. 1 R 2 R 3)Si-)functionalized resins as well as polybutadienes which have been functionalized at the end with silyl protecting groups. In connection with the test series, in the following the silyl protecting groups are not explicitly mentioned any more, such that "resins functionalized on the side groups" are understood to mean resins functionalized on the side groups with silyl protecting groups, "resins functionalized at the end" are understood to mean resins functionalized at the end with silyl protecting groups, and "liquid polybutadienes functionalized at the end" are understood to mean liquid polybutadienes functionalized at the end with silyl protecting groups.

[0062] In some cases, in the following the molar proportion of functionalization with silyl protecting groups is reported by quantification of the functionalization. The molar proportion is here related to the structural repeat unit, which is known as the smallest repeating unit in a polymer.

[0063] In the description in the following and in the tables, the amounts of the ingredients of the rubber mixtures are given in phr (parts by weight per hundred parts of rubber), which is common in rubber technology. The indications of amounts are each based on parts by mass of the base polymer, or in the case of polymer blends on parts by mass of the base polymers.

[0064] In the test series indicating the composition of the rubber mixtures, for some mixture ingredients the corresponding current trade name (October 2019) is given in brackets. The test series includes examples E1 to E19 of the inventive rubber mixtures as well as reference rubber mixtures R1 to R10.

[0065] 1sttest series - variation of the amount of resin

[0066] Table 2.1 shows the composition of the rubber mixtures of the 1sttest series. In the 1sttest series, the basic effect of a terminal functionalized liquid polybutadiene (BR) in combination with a terminal functionalized resin was examined (the corresponding indications of amounts in Table 2.1 are shaded in grey).

[0067] Table 2.1 : 1sttest series - composition of the rubber mixtures

[0068]

[0069] All rubber mixtures in the 1sttest series contain SBR rubber as base polymer and contain silica as filler.

[0070] The terminal functionalized liquid polybutadiene is not counted in the base polymer; it is present "on top" of the base polymer (SBR rubber).

[0071] The end-functionalized resin a is an a-methylstyrene-based resin, wherein 10% of the molar proportion has been functionalized with a silyl protecting group. Resin a was synthesized according to example 1.2 of WO 2018 / 191187 A1 (paragraphs

[0229] to

[0231] ) and has an average molecular weight Mn (number average molecular weight by gel permeation chromatography) of 699 g / mol. Resin a is present in the rubber mixtures E1 to E4 in an amount of 10 phr, 15 phr, 20 phr and 30 phr, respectively.

[0072] Formula I shows the structural formula of resin a.

[0073]

[0074] Additionally, a silane (bis(3triethoxysilylpropyl)disulfide), i.e. a silane coupling agent, as well as sulfur or a sulfur donor suitable for sulfur crosslinking are present. Further mixture ingredients include two accelerators (N-cyclohexyl-2-benzothiazole sulfenamide and 1,3-diphenylguanidine), two activators (stearic acid, zinc oxide), a processing effective material, and an aging stabilizer (N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine).

[0075] Table 2.2 shows the results of the vulcanized rubber tests performed for the rubber mixtures from Table 2.1.

[0076] Table 2.2: Test series 1 - vulcanized rubber tests

[0077] Vulcanizate properties R1 R2 R3 R4 E1 E2 E3 E4 Shore A hardness (T=25°C) 70.1 66.2 65.4 66.9 67.6 67.4 68.2 66.7 tan d (0°C) 0.203 0.144 0.298 0.347 0.210 0.233 0.265 0.331 tan d (70°C) 0.112 0.078 0.122 0.161 0.087 0.082 0.088 0.091 wear [mm 3 ]]]> 100 98 126 142 104 109 111 126

[0078] As shown by the comparison of the vulcanized rubbers made from R1 and R2, the use of the end-functionalized liquid polybutadiene (R2) only leads to a smaller loss factor tan d (0°C) (wet grip indicator) and a smaller loss factor tan d (70°C) (rolling resistance indicator). Thus, a tread made from the reference rubber mixture R2 - by comparison with a tread made from the reference rubber mixture R1 - has worse wet grip properties and lower (improved) rolling resistance. The abrasion resistance of the vulcanized rubbers made from R1 and R2 and thus of the corresponding treads is also similar (100 vs. 98).

[0079] The comparison of the vulcanized rubbers made from R1 and R3 shows that the use of the end-functionalized resin only (R3) leads to a larger loss factor tan d (0°C) (wet grip index) and a larger loss factor tan d (70°C) (rolling resistance index). Thus, a tread made from the reference rubber mixture R3 - by comparison with a tread made from the reference rubber mixture R1 - has better wet grip properties and a larger (deteriorated) rolling resistance. The abrasion resistance of the vulcanized rubber made from R3 is much worse (126 vs. 100) than the abrasion resistance of the vulcanized rubber made from R1.

[0080] As shown by the vulcanized rubber made from R4 by comparison with the vulcanized rubbers made from R3 and R1, the use of a larger amount of end-functionalized resin (R4) can further increase the loss factor tan d (0°C) (wet grip index), but the loss factor tan d (70°C) (rolling resistance index) also increases significantly. Thus, a tread made from the reference rubber mixture R4 has very good wet grip properties, but has a very high (significantly deteriorated) rolling resistance. In addition, the vulcanized rubber made from R4 shows a very high and thus worse abrasion value (142 vs. 126 or 100).

[0081] The vulcanized rubbers made from the inventive rubber mixtures E1 to E4 have a higher loss factor tan d (0°C) (wet grip index) than the vulcanized rubbers made from the reference rubber mixtures R1 and R2 and have a lower loss factor tan d (70°C) (rolling resistance index) than the vulcanized rubbers of the reference rubber mixtures R1, R3, R4. Thus, a tread made from the inventive rubber mixtures E1 to E4 - by comparison with a tread made from the reference rubber mixtures R1, R2 - has better wet grip properties and - by comparison with a tread made from the reference rubber mixtures R1, R3, R4 - has a significantly lower (improved) rolling resistance. In some cases, the abrasion resistance of the vulcanized rubbers made from E1 to E4 is significantly improved compared to the abrasion resistance of the vulcanized rubbers made from R3 and R4.

[0082] From the 1sttest series it follows that the vulcanized rubbers made from the inventive rubber mixtures E1 to E4 (comprising an end-functionalized liquid polybutadiene in combination with an end-functionalized resin) give improved wet grip properties and improved rolling resistance values without a loss in abrasion resistance.

[0083] 2ndtest series - linking group of the resin

[0084] In the 2ndtest series, the effect of a further end-functionalized resin (resin b) was examined, which is different from the end-functionalized resin a used in the 1sttest series.

[0085] Table 3.1 : 2nd test series - composition of rubber mixtures

[0086]

[0087]

[0088] The end-functionalized resin b is an a-methylstyrene-based resin, wherein 10% of the molar proportion has been functionalized with a silyl protecting group. Resin b was synthesized according to example 1.9 of WO 2018 / 191187 A1 (paragraphs

[0248] to

[0249] ) and has an average molecular weight Mn of 775 g / mol.

[0089] The structural formula of resin b is shown in formula II.

[0090]

[0091] Table 3.2: 2nd test series - vulcanized rubber tests

[0092] Vulcanizate properties R1 R5 E5 Shore A hardness (T=25°C) 70.1 62.9 66.7 tan d (0°C) 0.203 0.330 0.346 tan d (70°C) 0.112 0.117 0.098 wear [mm 3 ]]]> 100 148 117

[0093] The vulcanized rubber made from E5 has a larger loss factor tan d (0°C) (wet grip indicator) and a smaller loss factor tan d (70°C) (rolling resistance indicator) compared to the vulcanized rubbers made from R1 and R5, respectively. Thus, the tread manufactured from the rubber mixture E5 of the present application - by comparison with the treads manufactured from the reference rubber mixtures R1 or R5 - has better wet grip properties and lower (improved) rolling resistance. The abrasion resistance is significantly improved compared to the vulcanized rubber made from R5.

[0094] From the 2nd test series it can be concluded that advantageous vulcanized rubber properties can be achieved independently of the linking group structure of the resins.

[0095] 3rdtest series - resin base and functionalization position of the resin

[0096] In the 3rd test series it is shown that with resins having a pendant group functionalization as well as with resins having a different basis than the resins in the 1st and 2nd test series (in the 1st and 2nd test series based on a-methylstyrene) also advantageous effects can be achieved. Table 4.1 contains the corresponding compositions of the rubber mixtures.

[0097] Table 4.1 : 3rd test series - composition of rubber mixtures

[0098]

[0099] Resin d with pendent functionalization is an a-methylstyrene based resin, wherein 10% of the molar proportion has been functionalized with a silyl protecting group. Resin d was synthesized according to example 1.4 (paragraphs

[0235] to

[0237] ) of WO 2018 / 191187 A1 and has an average molecular weight Mn of 534 g / mol.

[0100] Resin e with pendent functionalization is a methyl acrylate based resin, wherein 10% of the molar proportion has been functionalized with a silyl protecting group. Resin e was synthesized according to example 1.8 (paragraphs

[0246] and

[0247] ) of WO 2018 / 191187 A1 and has an average molecular weight Mn of 876 g / mol.

[0101] Table 5.2: 3rdtest series - vulcanizates tests

[0102] Vulcanizate properties R7 R8 E12 E13 E14 E15 E16 E17 Shore A hardness (T=25°C) 70.9 70 70.2 70.2 70.8 69 67.6 67.2 tan d (0°C) 0.233 0.249 0.247 0.228 0.231 0.244 0.248 0.276 tan d (70°C) 0.093 0.116 0.097 0.088 0.088 0.104 0.098 0.112 wear [mm 3 ]]]> 108 114 89 98 96 88 84 83

[0103] By comparison with the vulcanizates made from R7 (the corresponding rubber mixtures "only" comprising a methacrylate based resin with pendent functionalization), the vulcanizates made from E12 to E14 (the corresponding rubber mixtures comprising a terminally functionalized liquid polybutadiene and a methacrylate based resin with pendent functionalization) show a significant improvement in wear (89 / 98 / 96 vs. 108) while the loss factor tan d(0°C) (wet grip indicator) and the loss factor tan d(70°C) (rolling resistance indicator) remain unchanged.

[0104] By comparison with the vulcanizates made from R8 (the corresponding rubber mixtures "only" comprising an a-methylstyrene based resin with pendent functionalization), the vulcanizates made from E15 to E17 (the corresponding rubber mixtures comprising a terminally functionalized liquid polybutadiene and an a-methylstyrene based resin with pendent functionalization) show a smaller tan d(70°C) (i.e. a reduced tread rolling resistance) as well as a significant improvement in wear (88 / 84 / 83 vs. 114).

[0105] From the 3rdtest series, it can be concluded that advantageous vulcanizate properties, especially wear resistance, can be achieved independently of the functionalization position of the resin (pendent, terminal) and independently of the resin base.

[0106] 4thtest series - amount of polybutadiene, type of polybutadiene, resin with different molecular weight and different functionalization position Vulcanizate properties

[0107] In the 4th test series, the effect of different amounts of end-functionalized liquid polybutadiene was examined, in which both the already mentioned POLYVEST EP ST-E 60 and "Ricon 603" were examined. Ricon 603 differs from POLYVEST EP ST-E 60 in that its glass transition temperature T g , its vinyl content and its ratio of cis- to trans-isomers (cis / trans ratio). The already mentioned end-functionalized resin b (Mn 775 g / mol) as well as the side group-functionalized resin c were used.

[0108] Table 4.1 : 4th test series - composition of the rubber mixtures

[0109]

[0110] The side group-functionalized resin c was synthesized by radical copolymerization according to Example 1.5 of WO 2018 / 191187 A1 (paragraphs

[0238] to

[0241] ) and has an average molecular weight Mn of 5320 g / mol.

[0111] Formula III shows the structural formula of resin c.

[0112]

[0113] Table 4.2: 4th test series - vulcanized rubber tests

[0114] Shore A hardness (T=25°C) R5 R6 E6 E7 E8 E9 E10 E11 tan d (0°C) 62.9 66.2 67.6 67.4 68.2 63.9 65 66.1 tan d (70°C) 0.330 0.252 0.234 0.217 0.203 0.340 0.343 0.378 5thtest series - amount of diene rubber and filler 0.117 0.119 0.099 0.094 0.085 0.084 0.075 0.070 wear [mm 3 ]]]> 148 123 112 108 103 107 109 135

[0115] As shown by the comparison of the vulcanizates made from rubber mixtures R5, E9, E10, E11 comprising resin b, the advantageous effects illustrated can also be achieved with Ricon 603. For example, the vulcanizates made from rubber mixtures E9, E10, E11 - in each case by comparison with the vulcanizate made from the reference rubber mixture R5 - have a greater loss factor tan d(0°C) (wet grip index) and a smaller loss factor tan d(70°C) (rolling resistance index); thus, they give a tread with better wet grip and rolling resistance properties. In particular, the vulcanizates made from rubber mixtures E9, E10, E11 - by comparison with the vulcanizate made from the reference rubber mixture R5 - each have a much greater difference between their tan d(0°C) value and tan d(70°C) value, which implies a particularly advantageous solution to the compromise existing between wet grip properties and rolling resistance. Surprisingly, the vulcanizates made from rubber mixtures E9, E10, E11 are also superior to the vulcanizate made from the reference rubber mixture R5 (107, 109, 135 vs. 148) in terms of their wear resistance. A small amount of Ricon 603 (E9, E10) is very beneficial for wear resistance.

[0116] The comparison of the vulcanizates made from rubber mixtures R6, E6, E7, E8 comprising resin c shows the effect of POLYVESTEP ST-E 60. The vulcanizates made from rubber mixtures E6, E7, E8 - in each case by comparison with the vulcanizate made from rubber mixture R6 - have a smaller loss factor tan d(0°C) value (wet grip index), a smaller loss factor tan d(70°C) value (rolling resistance index), and a smaller wear value. Rubber mixtures E6, E7, E8 thus give a tread which is more resistant to wear and has improved rolling resistance.

[0117] From the 4thtest series, it emerges that the advantageous vulcanizate properties can be achieved independently of the glass transition temperature T g of the polybutadiene, the vinyl content and the ratio of cis to trans isomers (cis / trans ratio). It has also been shown that the functionalization position of the resin (end group / side group) and its molecular weight have no significant, if any, influence.

[0118] Vulcanizate properties

[0119] In this test series, rubber mixtures comprising both SBR rubber and natural rubber and comprising a greater amount of filler than the current rubber mixtures (SBR / NR blends) were tested.

[0120] Table 5.1: 5thtest series - composition of the rubber mixtures

[0121]

[0122] The SBR rubber used in the 5th test series is HPR 840, which is a functionalized styrene-butadiene copolymer, which is prepared in a way described for example in EP 2 703 416 A1. HPR 840 is functionalized at the chain end with a silyl protecting group comprising an amino group and / or comprising an ammonium group. Such functionalization can be obtained by reacting the SBR rubber with an amino group containing alkoxysilyl compound having a protecting group at the amino group. For example, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane can be used. Other possible substances for such functionalization are stated in EP 2 703 416 A1. HPR 840 is obtained after deprotection (elimination of the protecting group).

[0123] HPR 840 is functionalized at the other chain end with an amino group. The amino group can be a primary, secondary or tertiary amino group, which can also be in cyclic form. The functionalization can be achieved by adding lithium amide in the polymerization as described in EP 2 703 416 A1 or by adding n-butyllithium and an amine (e.g. a cyclic amine, such as piperidine or piperazine) in the polymerization to produce the amide in situ.

[0124] The amino group at the other chain end is preferably a cyclic amino group. For this purpose, for example, piperidine can be added in combination with n-butyllithium in the polymerization.

[0125] Table 5.2: 5th test series - vulcanized rubber tests

[0126] Shore A hardness (T=25°C) R9 R10 E18 E19 tan d (0°C) 70.8 60.8 60.5 59.2 tan d (70°C) 0.508 0.603 0.66 0.567 Conclusions 0.145 0.159 0.128 0.099 wear [mm 3 ]]]> 106 127 100 111

[0127] By comparison with the vulcanized rubbers made from R9 and R10, the vulcanized rubbers made from E18 and E19 tend to have a larger loss factor tan d(0°C) (wet grip indicator) and a much smaller loss factor tan d(70°C) (rolling resistance indicator). Thus, the rolling resistance of a tire made from E18 or E19 is much lower compared to a tire made from R9 or R10. In addition, the wet grip of a tire made from E18 or E19 tends to be improved compared to a tire made from R9 or R10. The abrasion resistance tends to be improved.

[0128] It has been shown in the 5th test series that these effects are not limited to rubber mixtures comprising exclusively SBR rubber and can also be achieved with a large amount of filler.

[0129] ​

[0130] Table 6 shows a summary of the test series 1 to 5 that have been carried out.

[0131] Table 6: Test series summary

[0132]

[0133]

[0134] see WO 2018 / 191187 A1

[0135] It emerges in particular from the test series carried out that rubber mixtures comprising diene rubber containing resins which are functionalized with silyl protecting groups in the side groups or terminally functionalized, in combination with liquid polybutadienes which are terminally functionalized with silyl protecting groups, give vulcanizates which have advantageous wet grip properties, low rolling resistance and at least substantially constant abrasion resistance.

[0136] The application is not limited to the particular working examples described.

[0137] Various alternative mixture components are specified below for the rubber mixtures E1 to E19 which have been presented in the test series, i.e. for the working examples of the application, and are explained accordingly.

[0138] Diene rubber having an average molecular weight Mn of greater than 150 000 g / mol:

[0139] The rubber mixtures according to the application are sulphur-crosslinkable and contain at least one diene rubber.

[0140] Diene rubbers are rubbers which are formed by polymerization or copolymerization of dienes and / or cycloolefins and thus have C=C double bonds in the main chain or in the side groups.

[0141] The diene rubber(s) is / are preferably selected from the group of natural polyisoprene, synthetic polyisoprene, epoxidized polyisoprene, butadiene rubber, butadiene-isoprene rubber, solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, styrene-isoprene rubber, liquid rubber having a molecular weight Mw of greater than 20 000 g / mol, halogenated butyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluoro rubber, silicone rubber, polysulphide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile butadiene rubber, hydrogenated styrene-butadiene rubber, butyl rubber (IIR) and halobutyl rubber.

[0142] If the rubber mixture is intended for use in the tread of a vehicle tire, the diene rubber(s) are preferably selected from the group of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR).

[0143] In a preferred embodiment, the rubber mixture comprises at least one natural polyisoprene in an amount of 2 phr to 100 phr, in particular 5 phr to 30 phr, more preferably 5 phr to 20 phr. In this way, particularly good processability of the rubber mixture is achieved. Natural polyisoprene is understood to mean rubber obtained by harvesting from sources such as rubber trees (Hevea brasiliensis) or non-rubber tree sources (for example guayule or dandelion, for example Taraxacum koksaghyz). Natural polyisoprene (NR) is understood to mean non-synthetic polyisoprene.

[0144] In another advantageous embodiment, the rubber mixture comprises at least one polybutadiene (butadiene rubber) preferably in an amount of 2 phr to 100 phr, in particular 5 phr to 50 phr, more preferably 10 phr to 25 phr. In this way, particularly good wear properties and tensile properties of the rubber mixture are achieved, as well as good processability associated with low hysteresis loss.

[0145] In another particularly advantageous embodiment, the rubber mixture comprises at least one styrene-butadiene rubber (SBR), preferably SSBR, in an amount of 2 phr to 100 phr, in particular 25 phr to 80 phr, preferably 65 phr to 85 phr. In this way, good processability of the rubber mixture associated with low hysteresis loss, as well as good wear properties and tensile properties, are likewise achieved. The SBR is preferably SSBR, which results in optimized properties.

[0146] In another particularly advantageous embodiment, the rubber mixture comprises a polymer blend of the rubbers NR, BR and SBR, preferably SSBR, in the amounts specified respectively, in all possible combinations.

[0147] In another particularly advantageous embodiment, the rubber mixture comprises at least one natural and / or synthetic polyisoprene in an amount of 5 phr to 30 phr, at least one styrene-butadiene rubber in an amount of 25 phr to 80 phr, and at least one butadiene rubber in an amount of 5 phr to 50 phr.

[0148] Natural and / or synthetic polyisoprenes can in each case be cis-1,4-polyisoprenes or 3,4-polyisoprenes. Preference is given to using cis-1,4-polyisoprenes having a cis 1,4 content of > 90 % by weight. The polyisoprenes can be obtained by solution polymerization using Ziegler-Natta catalysts or by stereospecific polymerization using finely dispersed alkyl lithium. Natural rubber (NR) is a cis-1,4-polyisoprene in which the cis-1,4 content is greater than 99 % by weight.

[0149] Mixtures of one or more natural polyisoprenes with one or more synthetic polyisoprenes are further conceivable.

[0150] If the rubber mixture contains butadiene rubber (= BR, polybutadiene), it is of the type known to the person skilled in the art. These include the so-called high-cis type and the low-cis type, polybutadienes having a cis content of not less than 90 % by weight are referred to as high-cis type and polybutadienes having a cis content of less than 90 % by weight are referred to as low-cis type. An example of a low-cis polybutadiene is Li-BR (lithium-catalyzed butadiene rubber) having a cis content of 20 % by weight to 50 % by weight. High-cis BR achieves particularly good wear properties and low hysteresis of the rubber mixture.

[0151] The one or more polybutadienes employed can be end-group-modified and / or functionalized along the polymer chain by modification and functionalization. The modification can be selected from modification with hydroxyl and / or ethoxyl and / or epoxy groups and / or siloxane groups and / or amino groups and / or aminosiloxanes and / or carboxyl groups and / or phthalocyanine groups and / or silane-sulfide groups. However, other modifications known to the person skilled in the art, also referred to as functionalization, are also useful. Metal atoms can be constituents of such functionalization.

[0152] In the case where at least one styrene-butadiene rubber is present in the rubber mixture, this can be selected from solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR), and it is also possible to use mixtures of at least one SSBR and at least one ESBR. The terms "styrene-butadiene rubber" and "styrene-butadiene copolymer" are used synonymously in the context of the present application.

[0153] The styrene-butadiene copolymers used can be end-group-modified and / or functionalized along the polymer chain by the modifications and functionalizations mentioned above for polybutadienes.

[0154] The rubber can be used as pure rubber or in oil-extended form.

[0155] Fillers:

[0156] At least one arbitrary filler is present. Specifically, carbon black, silica, aluminosilicate, kaolin, chalk, starch, magnesium oxide, titanium dioxide, or rubber gel, as well as fibers (e.g., aramid fibers, glass fibers, carbon fibers, cellulose fibers) may be present in the rubber mixture and these fillers may be used in combination. The provided fillers may also be 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), graphite and graphene, and "carbon-silica biphase fillers".

[0157] Accordingly, the mixture may also contain two or more types of silica. These silicas may be those known to those skilled in the art and suitable as fillers for tire rubber compounds. However, finely dispersed precipitated silica with a density of 35 μm is particularly preferred. 2 / g to 400m 2 / g, preferably 35m 2 / g to 350m 2 / g, more preferably 85m 2 / g to 320m 2 / g and the optimal value is 120m 2 / g to 235m 2 / g nitrogen surface area (BET surface area) (according to DIN ISO 9277 and DIN 66132), and 30m 2 / g to 400m 2 / g, preferably 30m 2 / g to 330m 2 / g, more preferably 80m 2 / g to 300m 2 / g and the optimal value is 115m 2 / g to 200m 2 / g CTAB surface area (according to ASTM D 3765).

[0158] The silica used can therefore include, for example, not only from Evonik. Those of the VN3 (trade name) type, and silica with relatively low BET surface area (such as those from Solvay). 1115 or 1085), and also highly dispersible silica, known as HD silica (e.g., from Solvay). 1165 MPa). Silica preferably has a particle size greater than 130 μm. 2 CTAB value per g.

[0159] The amount of the at least one silica is especially 5 phr to 300 phr, preferably 10 phr to 200 phr, more preferably 20 phr to 180 phr. In case of different silicas, the indicated amounts mean the total amount of silica present.

[0160] In one embodiment, the carbon black has an iodine value (iodine adsorption value) according to ASTM D 1510 of 30 g / kg to 250 g / kg, especially 30 g / kg to 180 g / kg, preferably 40 g / kg to 180 g / kg, more preferably 40 kg / g to 130 kg / g, and a DBP value according to ASTM D 2414 of 80 ml / 100 g to 200 ml / 100 g, especially 100 ml / 100 g to 200 mg / 100 g, preferably 115 ml / 100 g to 200 ml / 100 g. The DBP value according to ASTM D 2414 determines the specific absorption volume of the carbon black or light-colored filler by means of dibutyl phthalate.

[0161] The use of this type of carbon black in rubber mixtures, in particular for vehicle tires, ensures the greatest possible compromise between wear resistance and heat build-up, which in turn affects the ecologically relevant rolling resistance. It is preferred to use a single species of carbon black, but it is also possible to use various different species of carbon black in combination. The carbon black is present in a total amount of at most 250 phr.

[0162] a polymer or oligomer having an average molecular weight Mn of less than 150 000 g / mol, which is functionalized with functional groups that interact with the filler and has a glass transition temperature T g :

[0163] At least one arbitrary polymer or oligomer having an average molecular weight Mn (number average molecular weight by gel permeation chromatography) of less than 150 000 g / mol, which is functionalized at any site with functional groups that interact with the filler and has a glass transition temperature T g of <-15°C, instead of the polybutadiene (BR) functionalized with silyl protecting groups at the termini used in the working examples.

[0164] "Interact with the filler" means that the polymer or oligomer interacts with the surface of the filler via van der Waals forces, dipole-dipole or electrostatic interactions or via covalent or non-covalent bonds, such as hydrogen bonds.

[0165] glass transition temperature T gPreferably <-20°C, more preferably <-30°C. It is further preferred that the average molecular weight Mn is from 500 g / mol to 50 000 g / mol, in particular from 1000 g / mol to 20 000 g / mol, more preferably from 3000 g / mol to 15000 g / mol.

[0166] Functionalization can be carried out with hydroxyl and / or ethoxyl and / or epoxy and / or siloxane and / or amino and / or aminosiloxane and / or carboxyl and / or anhydride and / or phthalocyanine and / or sulfurized silane groups. However, other modifications (functionalizations) known to the person skilled in the art are also useful. Metal atoms can be constituents of such functionalizations.

[0167] It is also advantageous if the mentioned polymers or oligomers comprise one or more silicon atoms. They have preferably been functionalized with silyl protecting groups of the formula IV:

[0168] (R 1 R 2 R 3 )Si- formula IV

[0169] R 1 , R 2 , R 3 : R 1 , R 2 , R 3 groups are independently selected from the group of linear or branched alkoxy, cycloalkoxy, alkyl, cycloalkyl, aryl or hydroxyl each having from 1 to 20 carbon atoms or hydrogen.

[0170] The silyl protecting groups of the formula IV can be attached to the polymer chain of the polymer or oligomer directly or via a bridge. The bridge can be formed by a saturated or unsaturated hydrocarbon group which can comprise heteroatoms, in particular sulfur and / or nitrogen.

[0171] The functionalization can be one of those mentioned above and can have a functionality of, for example, 0.0006 mol% to 100 mol% of monomers, in particular 0.05 mol% to 70 mol% of monomers, preferably 0.1 mol% to 50 mol% of monomers, wherein the functionalization can be carried out at the end or in the chain.

[0172] The polymer or oligomer functionalized with groups that interact with the filler can be present in an amount of, in particular, 5 phr to 200 phr, preferably 10 phr to 150 phr, more preferably 10 phr to 100 phr.

[0173] In addition, unfunctionalized polymers or oligomers or a combination of functionalized and unfunctionalized polymers or oligomers can be mixed into the mixture. The total amount of mixed-in polymers or oligomers is from 2 phr to 200 phr, in particular from 5 phr to 150 phr, preferably from 10 phr to 100 phr. In addition, a combination of functionalized polymers and oligomers can be used. In particular, a combination of end-group functionalized and side-group functionalized oligomers or polymers can be used.

[0174] Useful polymers or oligomers here include all polymers having a Tg of <-15°C and thus also include polyolefins such as poly(vinylidene chloride), polyethylene, poly(vinylidene fluoride), poly(acrylate), poly(decyl methacrylate), poly(dodecyl methacrylate), poly(isodecyl methacrylate), poly(octyl methacrylate), polypropylene, poly(1-butene), poly(1-octene), poly(1-pentene), poly(isopentene), poly(1-methyl-1-butene), poly(caprolactone), poly(1,4-butanediol succinate), poly(ethylene adipate), poly(3-hexyloxypropylene oxide), poly(dipropyl fumarate), poly(ethylene glycol), poly(propylene glycol), poly(propylene glycol), polyacetals, poly(ether), poly(vinyl ethyl ketone), poly(butyl vinyl sulfide), and also the above-mentioned rubbers consisting of polyisoprene, epoxidized polyisoprene, butadiene rubber, butadiene-isoprene rubber, styrene-butadiene rubber, styrene-isoprene rubber, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, polycyclopentene rubber, fluoro rubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile-butadiene rubber, hydrogenated styrene-butadiene rubber, farnesene, and liquid rubber having a molecular weight Mw of greater than 20 000 g / mol.

[0175] The polymer or polymers are preferably selected from the group of polyethylene, polypropylene, natural polyisoprene, synthetic polyisoprene, epoxidized polyisoprene, butadiene rubber, butadiene-isoprene rubber, solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, styrene-isoprene rubber, liquid rubber having a molecular weight Mw of greater than 20 000 g / mol, halobutyl rubber, polynorbornene, isoprene-isobutylene copolymer, ethylene-propylene-diene rubber, nitrile rubber, chloroprene rubber, acrylate rubber, fluoro rubber, silicone rubber, polysulfide rubber, epichlorohydrin rubber, styrene-isoprene-butadiene terpolymer, hydrogenated acrylonitrile-butadiene rubber, hydrogenated styrene-butadiene rubber, and farnesene.

[0176] In addition, combinations of the above-mentioned oligomers or polymers can be used.

[0177] a polymer or oligomer having an average molecular weight Mn of less than 150 000 g / mol, which is functionalized with functional groups interacting with the filler and which has a glass transition temperature Tg of > -15 °C g :

[0178] The resin used in the working example which is end-functionalized with a silyl protecting group is any resin having a glass transition temperature Tg of > -15 °C, in particular of > -10 °C g , at any site, with functional groups interacting with the filler.

[0179] The molecular weight Mn is in particular from 200 g / mol to 150 000 g / mol, preferably from 200 g / mol to 50 000 g / mol, more preferably from 200 g / mol to 30 000 g / mol. The glass transition temperature (Tg) is in particular below 200 °C, preferably below 180 °C, and more preferably below 160 °C.

[0180] In addition, combinations of the oligomers or polymers having different molecular weights can be used.

[0181] Functionalization can be carried out with hydroxyl and / or ethoxyl and / or epoxy and / or siloxane and / or amino and / or aminosiloxane and / or carboxyl and / or anhydride and / or phthalocyanine and / or sulfurized silane groups. However, other modifications (functionalizations) known to the person skilled in the art are also useful. Metal atoms can be constituents of such functionalizations.

[0182] This polymer or oligomer is preferably likewise already functionalized with a silyl protecting group having the formula IV already mentioned, as described in WO 2015 / 153055 for dicyclopentadiene (DCPD). Alternatively, it is preferred that it has been functionalized with a silyl protecting group having the formula V:

[0183] -[Z k -X n -R 4 -(CH2) m -Si(R 5 ) p ] q Formula V

[0184] In formula V,

[0185] -Z is an aromatic or aliphatic radical, optionally with one or more heteroatoms,

[0186] -X is a linking group comprising sulfur and / or oxygen and / or nitrogen and / or a carbonyl group,

[0187] -R 4 is one or more aliphatic radicals having 1 to 18 carbon atoms and / or a linking radical to at least one heteroatom, in particular to oxygen, nitrogen or sulfur,

[0188] -R 5 is a branched or unbranched alkoxy, aryloxy, alkyl or aryl radical having 1 to 18 carbon atoms, hydrogen or hydroxyl, wherein at least one R 5 is an alkoxy or aryloxy radical having 1 to 18 carbon atoms, a hydrogen atom or a hydroxyl radical, wherein R 5 may be identical or different,

[0189] q is an integer > 1,

[0190] k is 0 or 1,

[0191] n is an integer from 1 to 10,

[0192] m is an integer from 0 to 10, and

[0193] p is 1, 2 or 3.

[0194] The functionalization can be one of those described above and can have a functionality of, for example, 0.0006 mol% to 100 mol% of monomers, 0.05 mol% to 70 mol% of monomers, preferably 0.1 mol% to 50 mol% of monomers, wherein the functionalization can be carried out at the end or in the chain. The polymer or oligomer functionalized with radicals that interact with the filler can be used in an amount of 5 phr to 200 phr, in particular 10 phr to 150 phr, more preferably 10 phr to 100 phr.

[0195] Furthermore, unfunctionalized polymers or oligomers can be mixed into the mixture or a combination of functionalized and unfunctionalized polymers or oligomers can be mixed into the mixture. The total amount of polymers or oligomers mixed in is 2 phr to 200 phr, 5 phr to 150 phr or 10 phr to 100 phr.

[0196] Preferred for use are oligomers or polymers, in particular based on the polymerization or copolymerization of two or more unsaturated aliphatic monomers, unsaturated aromatic monomers, terpenes, terpene-phenol, abietic acid, rosin, unsaturated cyclic aromatic monomers, unsaturated alicyclic monomers, unsaturated fatty acids, methacrylate and / or vinylaromatic monomers or mixtures of aliphatic and aromatic monomers. The aliphatic monomers can be selected from C5 1,3-pentadiene, benzofuran (coumarone), indene, indane, as described in WO2018118855 A1, and dicyclopentadiene. The aromatic monomers and / or vinylaromatic monomers can be selected, for example, from styrene, vinyltoluene, a-methylstyrene and diisopropylbenzene.

[0197] The monomers of the terpene can be monocyclic terpenes and / or bicyclic terpenes.

[0198] The oligomers or polymers can also be selected from the group of polyolefins, polyesters, polyethers, polythioethers, polyketones, polyphthalates, polyterephthalates, polyacrylamides, polylactates, polycarbonates, polyacetates, polyketones, polymethacrylates, polyacrylates, polymethacrylonitriles and polyacrylonitriles, polyamides as oligomers or polymers.

[0199] These oligomers or polymers include, in particular, a-methylstyrene, styrene, vinyltoluene, diisopropylbenzene, 1,3-pentadiene, benzofuran (coumarone), indene, indane, dicyclopentadiene, terpene, ethyl-vinylacetate, ethyl-vinylbutyrate and styrene block copolymers.

[0200] In addition, combinations of functionalized polymers or oligomers can be used. In particular, combinations of end group functionalized and side group functionalized oligomers or polymers can be used.

[0201] Silanes:

[0202] Silanes are optionally used in the mixtures of the application, in particular when the mentioned selection of polymers or oligomers with Tg<-15°C or Tg>-15°C cannot achieve the optimal crosslinking of the diene rubber and thus the optimal adhesion of the diene rubber to the filler.

[0203] A coupling agent or organosilicon compound in the form of a silane is preferably present in the rubber mixture. One silane or different silanes in combination with one another can be used. Useful silanes are mentioned, for example, in WO 2018 / 191187 A1 in paragraph

[0094] .

[0204] Silane coupling agents can be used as adhesion promoters for inorganic materials (e.g. glass beads, glass fragments, glass surfaces, glass fibers), for oxide-type fillers (preferably silica) and for organic polymers (e.g. thermosets, thermoplastics or elastomers) or as crosslinking agents and as surface modifiers for oxide-type surfaces.

[0205] During mixing of the rubber / rubber mixture (in situ) or in the context of a pre-treatment (pre-modification) even before the addition of the filler to the rubber, the silane coupling agent reacts with the surface silanol groups or other polar groups of the silica.

[0206] The silane coupling agents which can be used here include any silane coupling agents known to the person skilled in the art for 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 have as further functional group a group which can participate in a chemical reaction with a double bond of a polymer after cleavage, if necessary. The latter group can be, for example, one of the following chemical groups: -SCN, -SH, -NH2 or -Sx- (where x = 2 to 8).

[0207] The silane coupling agents which can be used therefore include, for example, 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane or 3,3'-bis(triethoxysilylpropyl) polysulphides having 2 to 8 sulphur atoms, for example 3,3'-bis(triethoxysilylpropyl) tetrasulphide (TESPT), the corresponding disulphide (TESPD) or mixtures of further sulphides having 1 to 8 sulphur atoms with varying contents of the respective sulphides. TESPT can also be added, for example, as a mixture with carbon black (trade name Si-PEG® from Evonik) Preferably, silane mixtures containing from 40% by weight to 100% by weight disulphide, more preferably from 55% by weight to 85% by weight disulphide and most preferably from 60% by weight to 80% by weight disulphide are used.

[0208] Capped mercaptosilanes, as known, for example, from WO 99 / 09036, can also be used as silane coupling agents. Silanes as described in WO 2008 / 083241 Al, WO 2008 / 083242 Al, WO 2008 / 083243 Al and WO 2008 / 083244 Al can also be used. It is possible to use, for example, the silanes marketed by Momentive, USA, under the name NXT in various variants, or by Evonik Industries under the name VP Si those sold under the name Si-44®. The amount of silane coupling agent is preferably from 0.1 to 20 phf, more preferably from 1 to 15 phf.

[0209] Explanation of the hydrolysable groups of the silane:

[0210] (R1)oSi-R2

[0211] wherein:

[0212] o is 1, 2 or 3.

[0213] The R1 groups are identical or different and are selected from the group consisting of alkoxy groups having from 1 to 10 carbon atoms, cycloalkoxy groups having from 4 to 10 carbon atoms, phenoxy groups, aryl groups having from 6 to 20 carbon atoms, alkyl groups having from 1 to 10 carbon atoms, alkenyl groups having from 2 to 20 carbon atoms, aralkyl groups having from 7 to 20 carbon atoms, alkyl polyether groups -0-(R3-0)r-R5 (wherein R3 is identical or different and is a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C10 hydrocarbon group, preferably -CH2-CH2-, and wherein r is an integer from 1 to 30, preferably from 3 to 10, and R5 is an unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl group, preferably -CH3), and halide groups. 30 H 13 H 27 alkyl, or halide).

[0214] Here two R1 can form a cyclic dialkoxy group having from 2 to 10 carbon atoms, or two R1 can each come from a different molecule to constitute a bridging oxygen atom, in which case one R1 in each molecule is an alkoxy or halide group.

[0215] The group R2 is a linear or branched alkyl group having from 1 to 20 carbon atoms, a cycloalkyl group having from 4 to 12 carbon atoms, an aryl group having from 6 to 20 carbon atoms, an aralkyl group having from 7 to 20 carbon atoms, an alkenyl group having from 2 to 20 carbon atoms, or an alkynyl group having from 2 to 20 carbon atoms.

[0216] The silane can be applied to a carrier, such as a wax, a polymer or carbon black, and can be added to the rubber mixture in this form. The silane of the present invention can be applied to silica, in which case the attachment can be physical or chemical.

[0217] Plasticizer / processing aid:

[0218] Processing aids are understood to mean oils and other viscosity-reducing substances. These processing aids can be, for example, plasticizer oils or plasticizer resins.

[0219] Processing aids are for example aromatic, naphthenic or paraffinic mineral oil plasticizers, such as MES (mild extract solvate) or RAE (residual aromatic extract) or TDAE (treated distillate aromatic extract) or rubber-made liquid oil (RTL) or biomass-made liquid oil (BTL) or oil paste or plasticizer resin or liquid polymer (such as liquid BR) with an average molecular weight (determined by GPC = gel permeation chromatography according to BS ISO 11344:2004) between 500 g / mol and 20000 g / mol. If a liquid polymer is used as plasticizer in the rubber mixture of the present application, these are not counted as rubber in the calculation of the composition of the polymer matrix. When a mineral oil is used, it is preferably selected from the group consisting of DAE (distilled aromatic extract) and / or RAE (residual aromatic extract) and / or TDAE (treated distilled aromatic extract) and / or MES (mild extracted solvent) and / or naphthenic oil.

[0220] It will be clear to the person skilled in the art that a hydrocarbon resin is a polymer constructed from monomers, wherein the hydrocarbon resin is formally constructed from derivatives of these monomers by the monomers connecting to each other. However, these hydrocarbon resins are not considered to be rubber in the context of the present application. The term "hydrocarbon resin" in the context of the present application includes resins comprising carbon atoms and hydrogen atoms and can optionally include heteroatoms, such as in particular oxygen atoms. The hydrocarbon resin can be a homo- or copolymer. In the present application, according to In online version 3.28, the term "homo-polymer" is understood to mean a polymer "formed from only one type of monomer".

[0221] The monomers can be any hydrocarbon resin monomers known to the person skilled in the art, such as aliphatic C5 monomers, further unsaturated compounds capable of cationic polymerization, including aromatic compounds and / or terpenes, terpene-phenols and / or olefins and / or cyclic olefins.

[0222] In a preferred embodiment of the present application, the hydrocarbon resin is selected from the group consisting of aliphatic C5 resins and hydrocarbon resins formed from alpha-methylstyrene and styrene.

[0223] The hydrocarbon resin preferably has an ASTM E28 (ball and ring method) softening point of 10 °C to 180 °C, in particular 60 °C to 150 °C, more preferably 80 °C to 99 °C.

[0224] Furthermore, the hydrocarbon resin preferably has a molecular weight Mw of 500 g / mol to 4000 g / mol, preferably 1300 g / mol to 2500 g / mol.

[0225] Crosslinking agent (vulcanizing agent):

[0226] The crosslinking agent used is preferably at least sulfur or at least a sulfur donor and a peroxide crosslinking substance such as an organic peroxide, for example dicumyl peroxide, di(2,4-dichlorobenzoyl) peroxide, tert-butyl peroxybenzoate, 1,1 -di(tert-butylperoxy)-3,3,5-trimethylcyclohexane, n-butyl 4,4-di(tert-butylperoxy)valerate, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexyne-3, di-tert-butyl peroxide, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, di-(2-tert-butylperoxyisopropyl)benzene or tert-butyl cumyl peroxide or combinations thereof. Further alternatives used can be crosslinking agents as specified in WO 2018 / 191 187 A1 paragraph

[0094] .

[0227] Accelerators and activators:

[0228] Accelerators and activators are optional mixture ingredients; they are in particular components of sulfur accelerator crosslinking systems and are therefore preferably used in combination with sulfur or a sulfur donor. Possible accelerators can be found for example in WO 2018 / 191 187 A1 paragraph

[0094] .

[0229] In the final mixing step, the sulfur or sulfur donor and the accelerator(s) are added to the rubber mixture in the amounts specified.

[0230] The accelerators are preferably selected from the group consisting of thiazole accelerators and / or mercapto-containing 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.

[0231] Examples are N-cyclohexyl-2-benzothiazole sulfenamide (CBS), N,N-dicyclohexylbenzothiazole-2-sulfenamide (DCBS), benzothiazyl-2-sulfenamide morpholine (MBS) and N-tert-butyl-2-benzothiazylsulfenamide (TBBS), diphenyl guanidine (DPG).

[0232] It is also possible to use further network-forming systems in the rubber mixture as for example in or under the trade name of Oxymer® or network-forming systems as described in WO 2010 / 049261 A2.

[0233] Further optional ingredients:

[0234] a) Age stabilizers:

[0235] For example 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).

[0236] b) activators:

[0237] For example fatty acids (e.g. stearic acid) and / or zinc oxide (ZnO pellets or powder). Zinc oxide which is conventionally used usually has a BET surface area of less than 10 m2 / g. Alternatively, so-called nano-zinc oxide having a BET surface area of 10 m2 / g to 60 m2 / g can be used. 2 2 2

[0238] c) waxes

[0239] d) resins, in particular tackifying resins,

[0240] e) plasticizing aids, for example 2,2'-dibenzamidodiphenyl disulfide (DBD), and

[0241] f) processing aids, for example fatty acid salts (e.g. zinc soaps), fatty acid esters and derivatives thereof, and lipids and phospholipids, in particular lecithin, for example soy lecithin.

[0242] g) reinforcing resins, for example lignin, phenol-formaldehyde resin with hardener, and polymeric resins.

[0243] h) cobalt salts and others

[0244] For improving the rubber-metal adhesion, it has long been known to use cobalt salts and / or resorcinol-formaldehyde-silica systems or resorcinol-formaldehyde systems as additives for rubberized mixtures. Precondensates of resorcinol resins can also be used. Rubberized mixtures comprising cobalt salts and resorcinol-formaldehyde-silica systems are known, for example, from KGK Kautschuk Gummi Kunststoffe No. 5 / 99, pages 322 to 328, GAK 8 / 1995, page 536, and EP-A-1 260 384.

[0245] i) reinforcing resins

[0246] ​​​The reinforcing agent resin can for example be based on a methylene donor such as hexamethoxymethyl melamine (HMMM) or hexamethylenetetramine (HMT) and a methylene acceptor such as resorcinol, phenol or a resorcinol derivative, a phenol derivative or an acetone derivative. For example it is possible to use a methylene acceptor based on a resorcinol-formaldehyde novolak resin, a resorcinol-formaldehyde-styrene novolak resin, a phenol-formaldehyde novolak resin (for example product), a phenol-formaldehyde-styrene novolak resin, a phenol-formaldehyde-urethane novolak resin or an acetone novolak resin. The reinforcing agent resin preferably contains less than 0.1 % of unbound resorcinol and less than 1 % of unbound phenol.

[0247] The reinforcing agent resin can also be exclusively based on a methylene donor such as hexamethoxymethyl melamine (HMMM) or hexamethylenetetramine (HMT).

[0248] j) cobalt

[0249] Cobalt is preferably present in a steel cord adhesive system based on an organic cobalt salt and a reinforcing agent resin and more than 2.5 phr of sulphur. These organic cobalt salts are typically used in an amount of 0.2 to 2 phr. The cobalt salt used can be for example cobalt stearate, cobalt borate, cobalt borate-alkanoate, cobalt naphthenate, cobalt rhodinate, cobalt octoate, cobalt adipate etc.

Claims

1. A crosslinkable rubber mixture, comprising: a) a diene rubber having a number average molecular weight Mn of more than 150 000 g / mol, b) a filler, c) a polymer having a number average molecular weight Mn of less than 150 000 g / mol, the polymer having functional groups interacting with the filler and a glass transition temperature Tg of <-15°C, d) a polymer having a number average molecular weight Mn of less than 150 000 g / mol, the polymer having functional groups interacting with the filler and a glass transition temperature Tg of >-15°C, wherein interacting with the filler means that the polymer interacts with the surface of the filler via covalent or non-covalent bonds, that the components c) and d) have different glass transition temperatures Tg, and that the temperature difference ATg between the glass transition temperatures Tg of component c) and component d) is at least 5°C.

2. The rubber mixture according to claim 1, characterized in that The rubber mixture comprises silica and / or carbon black as filler.

3. Rubber mixtures according to claim 1 or 2, characterized in that The polymer of feature c) is a diene-based polymer.

4. Rubber mixtures according to claim 1 or 2, characterized in that The polymer of feature c) has a number average molecular weight Mn of 500 g / mol to 50 000 g / mol, determined by gel permeation chromatography.

5. The rubber mixture according to claim 4, wherein The polymer of feature c) has a number average molecular weight Mn of 1000 g / mol to 20 000 g / mol, determined by gel permeation chromatography.

6. The rubber mixture of claim 4, wherein, The polymer of feature c) has a number average molecular weight Mn of 3000 g / mol to 15 000 g / mol, determined by gel permeation chromatography.

7. Rubber mixtures according to claim 1 or 2, characterized in that The polymer of feature c) has been functionalized with a silyl protecting group.

8. Rubber mixtures according to claim 1 or 2, characterized in that, The polymer of feature c) is a polybutadiene functionalized with functional groups interacting with the filler.

9. Rubber mixtures according to claim 1 or 2, characterized in that The polymer of feature c) and / or the polymer of feature d) has been functionalized with a silyl protecting group of formula IV: (R 1 R 2 R 3 )Si- Formula IV wherein, R 1 , R 2 , R 3 are independently selected from the group of linear or branched alkoxy, cycloalkoxy, alkyl, cycloalkyl, aryl or hydroxyl groups having in each case 1 to 20 carbon atoms, or hydrogen, and wherein the silyl protecting group of formula IV is attached to the polymer chain of the polymer directly or via a bridge, and wherein the bridge is formed by a saturated or unsaturated hydrocarbon group comprising a heteroatom.

10. The rubber mixture according to claim 9, characterized in that The bridge is formed by a saturated or unsaturated hydrocarbon group comprising sulfur and / or nitrogen.

11. Rubber mixtures according to claim 1 or 2, characterized in that The polymer of feature d) has been functionalized with the silyl protecting group of formula V: -[Z k -X n -R 4 -(CH2) m -Si(R 5 ) p ] q Formula V wherein, - Z is an aromatic or aliphatic group having one or more heteroatoms, - X is a linking group comprising sulfur and / or oxygen and / or nitrogen and / or a carbonyl group, -R 4 one or more aliphatic groups having 1 to 18 carbon atoms and / or a linking group to at least one heteroatom, -R 5 is a branched or unbranched alkoxy, aryloxy, alkyl or aryl group having 1 to 18 carbon atoms, a hydrogen or a hydroxyl group, wherein at least one R 5 is an alkoxy or aryloxy group having 1 to 18 carbon atoms, a hydrogen atom or a hydroxyl group, wherein in the molecule R 5 are identical or different, - q is an integer > 1, - k is 0 or 1, - n is an integer from 1 to 10, - m is an integer from 0 to 10, and - p is 1, 2 or 3.

12. The rubber mixture of claim 11, wherein, The heteroatom is oxygen, nitrogen or sulfur.

13. The rubber mixture according to claims 1 or 2, characterized in that The polymer of feature d) is a resin based on unsaturated aliphatic monomers, unsaturated aromatic monomers, terpenes, rosins, unsaturated cycloaliphatic monomers, unsaturated fatty acids and / or methacrylates.

14. The rubber mixture according to claims 1 or 2, characterized in that The polymer of feature d) has a number average molecular weight Mn of 200 g / mol to 150 000 g / mol.

15. The rubber mixture of claim 14, wherein, The polymer of feature d) has a number average molecular weight Mn of 200 g / mol to 50 000 g / mol.

16. The rubber mixture of claim 14, wherein, The polymer of feature d) has a number average molecular weight Mn of 200 g / mol to 30 000 g / mol.

17. The rubber mixture according to claims 1 or 2, characterized in that The polymer of feature c) and the polymer of feature d) are present in a ratio of 1 :50 to 50:

1.

18. The rubber mixture of claim 17, wherein, The polymer of feature c) and the polymer of feature d) are present in a ratio of 1 :10 to 10:

1.

19. The rubber mixture of claim 17, wherein, The polymer of feature c) and the polymer of feature d) are present in a ratio of 1 :5 to 5:

1.

20. The rubber mixture of claim 17, wherein, The polymer of feature c) and the polymer of feature d) are present in a ratio of 1 :3 to 3:

1.

21. The rubber mixture according to claims 1 or 2, characterized in that, the determined temperature difference ΔΤ between the glass transition temperature Tg of the polymer of feature c) g and the glass transition temperature Tg of the polymer of feature d) g is at least 10 °C. g is at least 10 °C.

22. The rubber mixture according to claims 1 or 2, characterized in that, The rubber mixture contains at least one silane coupling agent.

23. A pneumatic vehicle tire comprising at least one tire component consisting of rubber, said tire component being at least partially manufactured from the rubber mixture according to any one of claims 1 to 22.

24. The pneumatic vehicle tire of claim 23, wherein, The tire component is a tread.

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