Vulcanisable rubber mixture, vulcanised material, and rubber product

Abstract

The invention relates to a vulcanisable rubber mixture comprising: a) diene rubbers; b) silicas; c) specific polyether amines, in a combined mass fraction in the range of 0.1 to 10 phr; and d) one or more liquid polybutadienes, the one or more liquid polybutadienes having a number average molecular weight Mn, measured using GPC, in the range of 500 to 20,000 g / mol.

Description

[0001] Vulcanizable rubber compound, vulcanizate and rubber product

[0002] Description

[0003] The invention relates to a vulcanizable rubber mixture, a vulcanizate producible therefrom and a rubber product containing this vulcanizate, in particular a pneumatic vehicle tire.

[0004] The automotive industry is one of the sectors that has faced fundamental challenges since the beginning of the 21st century and has simultaneously been shaped by numerous technological innovations. Growing customer awareness of environmental aspects such as emissions profiles and resource efficiency requires new mobility concepts. At the same time, demand for improved vehicle performance and requirements regarding driving safety are increasing. Meeting these challenges is not solely the responsibility of the actual vehicle manufacturers. In practice, many of these aspects are strongly influenced by the properties of vehicle tires, making the optimization of tire properties an important field of innovation.

[0005] A key component for optimizing the properties of vehicle tires and other rubber products, such as belts, straps, and hoses, are the vulcanizable rubber compounds used in their production and the rubber materials obtained through vulcanization. Several relevant properties of pneumatic vehicle tires, such as wet grip, rolling resistance, and abrasion behavior, are closely linked to the composition of the rubber tread material. Therefore, much research effort is focused on optimizing the properties of the rubber compounds used, which are regularly subject to very high demands. Conflicting objectives exist with regard to numerous properties in vehicle tires, meaning that these properties cannot be optimized independently of one another, and an improvement in one parameter can lead to a deterioration in another.

[0006] Significant progress has been made in the field of composition development in recent decades. A key innovation, for example, has been the at least partial replacement of carbon black fillers with silicon-containing compounds, particularly silicon dioxide compounds such as fumed silica or precipitated silica.

[0007] EP 2725059 A1 discloses that the combination of polyetheramines and silica can produce advantageous rubber compounds that, in particular, exhibit improved performance with regard to abrasion behavior and the trade-off between rolling resistance and wet grip. Furthermore, it has been found that improved processing properties can be achieved in corresponding rubber compounds. Further information on the technological background of polyetheramines is disclosed, for example, in WO 2013 / 092526 A1, US 2008 / 033082 A1, and WO 2016 / 030469 A1.

[0008] Even though the vulcanizable rubber compounds known from the state of the art can achieve advantageous results in many respects, the corresponding compositions and the vulcanizates produced therefrom are in many cases still considered to be in need of improvement with regard to application-relevant properties, in particular in order to meet the requirements of modern pneumatic vehicle tires for high-performance applications.

[0009] The primary object of the present invention was to eliminate or at least reduce the disadvantages of the prior art and to provide an advantageous vulcanizable rubber mixture and a corresponding vulcanizate producible therefrom with an advantageous property profile.

[0010] In particular, it was the object of the present invention to provide a vulcanizable rubber mixture with excellent processing properties, wherein it was a desirable requirement that the need for potentially health and / or environmentally harmful compounds, in particular guanidine accelerators, could be reduced.

[0011] Furthermore, it was an object of the present invention to provide a vulcanizable rubber mixture and corresponding vulcanizates that can be produced therefrom, which have excellent mechanical properties, in particular with regard to stiffness and improved robustness, in particular also with regard to improved tear properties on rough roads, and in particular with regard to improved abrasion properties.

[0012] In particular, it was an object of the present invention to resolve existing conflicts of objectives between the processing properties and the mechanical properties in the best possible way.

[0013] It was a supplementary object of the present invention that the vulcanizable rubber mixtures and vulcanizates to be specified should be producible as far as possible using such production processes and materials that are already used today in the field of rubber processing.

[0014] It was a further object of the present invention to provide a corresponding rubber product comprising the vulcanizate to be specified, in particular a pneumatic vehicle tire with advantageous properties. The inventors of the present invention have now discovered that the above-described objects can surprisingly be achieved by using vulcanizable rubber mixtures which, in addition to diene rubber and silica, additionally comprise certain mass fractions of specific polyetheramines and liquid polybutadiene, as defined in the claims.

[0015] The above-mentioned objects are accordingly achieved by the subject matter of the invention as defined in the claims. Preferred embodiments of the invention emerge from the subclaims and the following statements.

[0016] Such embodiments, which are designated as preferred below, are combined in particularly preferred embodiments with features of other embodiments designated as preferred. Combinations of two or more of the embodiments designated as particularly preferred below are thus very particularly preferred. Likewise preferred are embodiments in which a feature of one embodiment designated as preferred to any extent is combined with one or more further features of other embodiments designated as preferred to any extent. Features of preferred vulcanizates, rubber products, and uses emerge from the features of preferred vulcanizable rubber mixtures.

[0017] To the extent that both specific amounts or proportions of a mixture component, for example for the diene rubbers or the polyetheramines, and preferred embodiments of the mixture component are disclosed below, the specific amounts or proportions of the preferably configured mixture components are also disclosed. Furthermore, it is disclosed that, for the corresponding specific total amounts or

[0018] Total proportions of the mixture components, at least a part of the mixture components can be preferably designed and in particular also that preferably designed mixture components can in turn be present in the specific amounts or proportions within the specific total amounts or total proportions.

[0019] The invention relates to a vulcanizable rubber mixture comprising: a) one or more diene rubbers, b) one or more fillers selected from the group consisting of silicas, c) one or more polyetheramines, in a combined mass fraction in the range of 0.1 to 10 phr, wherein the polyetheramines are selected from the group consisting of polyetheramines of the formula I):

[0020] I) R 1 R 2 N - (R 5 ) m - X - R 6 - NR 3 R 4 , where R 1 , R 2 , R 3 and R 4 are independently hydrogen or either branched or unbranched hydrocarbon radicals having 1 to 10 C atoms, where m is 0 or 1, where R 5 and R 6 are independently either branched or unbranched hydrocarbon chains having 1 to 10 C atoms, where X is a polyether chain of the formula II):

[0021] II) - (CHR 7i - CHR 8 ' - O)x -, where x is in the range of 2 to 30, where R 7i and R 8i in each monomer unit i, independently of one another and independently of the other monomer units of the polyether chain, are hydrogen or hydrocarbon radicals having 1 or 2 C atoms, and d) one or more liquid polybutadienes, wherein the one or more liquid polybutadienes have a number-average molar mass Mn, measured by GPC, in the range from 500 to 20,000 g / mol.

[0022] Vulcanizable rubber mixtures per se and their typical components as well as customary production processes for obtaining corresponding vulcanizable rubber mixtures, in particular by mixing the components, are comprehensively known to the person skilled in the art in the field of rubber processing.

[0023] In accordance with standard practice, the above-defined components of the vulcanizable rubber compound are each referred to as "one or more." The term "one or more" refers, as is customary in the industry, to the chemical nature of the respective compounds, not to their quantity. For example, the vulcanizable rubber compound may comprise exclusively SBR as a diene rubber, which would mean that the vulcanizable rubber compound comprises a plurality of the respective molecules.

[0024] Insofar as mass fractions are stated below, these are in many cases stated as combined mass fractions of one or more components, in accordance with industry practice, thereby expressing that the mass fraction of the correspondingly formed components taken together meets the corresponding criteria.

[0025] The term phr (parts per hundred parts of rubber by weight) is the quantity commonly used in the rubber industry for compound recipes, which specifies the mass fractions of the components in the rubber mixture based on the mass of the high-molecular-weight rubbers present in the rubber mixture (number-average molar mass Mn according to GPC greater than 60,000 g / mol), whereby the combined mass fraction of these high-molecular-weight rubbers in the rubber mixture corresponds to 100 phr. The term phf (parts per hundred parts of filler by weight) is analogously the quantity commonly used in the rubber industry for compound recipes, in particular for coupling agents for fillers, based on the mass of the fillers present in the rubber mixture.In the context of the present invention, the phf specification refers only to the silicas present in the vulcanizable rubber mixture, the combined mass fraction of which corresponds to 100 phf, so that other fillers that may be present, such as carbon black, are not included in the calculation of the phf.

[0026] The vulcanizable rubber mixture according to the invention comprises at least one diene rubber. In accordance with the expert understanding, diene rubbers are referred to as rubbers obtained by (co)polymerization of dienes and / or cycloalkenes and thus having C=C double bonds either in the main chain or in the side groups. It can be seen as an advantage of the vulcanizable rubber mixture according to the invention that it is very flexible with regard to the diene rubbers to be used, so that in principle all diene rubbers customary in the industry can be used. However, in the opinion of the inventors, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more diene rubbers are selected from the group consisting of natural polyisoprene, synthetic polyisoprene, epoxidized polyisoprene, butadiene rubber, solution-polymerized styrene-butadiene rubber,emulsion-polymerized styrene-butadiene rubber, polynorbornene, ethylene-propylene-diene rubber, nitrile rubber, acrylate rubber, styrene-isoprene-butadiene terpolymer, butyl rubber and halobutyl rubber, wherein the one or more diene rubbers are preferably selected from the group consisting of natural polyisoprene (NR), synthetic polyisoprene (IR), butadiene rubber (BR), solution-polymerized styrene-butadiene rubber (SSBR) and emulsion-polymerized styrene-butadiene rubber (ESBR), wherein the one or more diene rubbers are particularly preferably selected from the group consisting of solution-polymerized styrene-butadiene rubber and emulsion-polymerized styrene-butadiene rubber. In this respect, additionally or alternatively, a vulcanizable rubber mixture according to the invention is also preferred, wherein at least one of the diene rubbers, preferably all of the one or more diene rubbers,is an end-group-modified and / or chain-modified diene rubber, preferably an end-group-modified diene rubber. The modification may be one or more functional groups selected from the group consisting of hydroxyl groups, ethoxy groups, epoxy groups, siloxane groups, amino groups, aminosiloxane groups, carboxy groups, phthalocyanine groups, and silane sulfide groups.

[0027] SBR, BR and IR or NR have proven particularly suitable as diene rubbers for obtaining vulcanizable rubber compounds that can be converted into particularly high-performance vulcanizates by vulcanization.

[0028] Thus, firstly, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises styrene-butadiene rubber, preferably solution-polymerized styrene-butadiene rubber, as diene rubber, preferably in a mass fraction in the range from 50 to 98 phr, particularly preferably in the range from 55 to 96 phr, very particularly preferably in the range from 60 to 90 phr.

[0029] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises butadiene rubber as diene rubber, preferably in a mass fraction in the range from 1 to 35 phr, particularly preferably in the range from 2 to 30 phr, very particularly preferably in the range from 5 to 25 phr. The butadiene rubber can, for example, be so-called high-cis or low-cis types, wherein polybutadiene with a mass-related cis content of 90% or more is referred to as a high-cis type.

[0030] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises natural polyisoprene and / or synthetic polyisoprene, preferably natural polyisoprene, as diene rubber, preferably in a combined mass fraction in the range from 1 to 30 phr, more preferably in the range from 2 to 20 phr, most preferably in the range from 5 to 15 phr. However, particularly for applications for truck tires, mass fractions in the range from 60 to 100 phr, preferably 60 to 80 phr are also conceivable. The natural and / or synthetic polyisoprene can be either cis-1,4-polyisoprene or 3,4-polyisoprene. However, the use of cis-1,4-polyisoprenes is preferred, in particular with a mass fraction of cis-1,4 of 90% or more.

[0031] To optimally adapt the physicochemical and mechanical properties of the vulcanizates produced to the respective application requirements, it has proven advantageous to mix two or more diene rubbers together. Accordingly, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises two or more, preferably three or more, different diene rubbers as the diene rubber. The vulcanizable rubber mixture particularly preferably comprises SBR and NR and / or BR, very particularly preferably SBR, NR, and BR.

[0032] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the diene rubber(s) has(have) a weight-average molar mass Mw, measured by GPC, in the range from 150,000 to 5,000,000 g / mol, preferably in the range from 250,000 to 2,500,000, particularly preferably in the range from 300,000 to 1,500,000. The number-average or weight-average molar mass is determined in the context of the present invention by gel permeation chromatography according to DIN 55672-1: 2016-03 (GPC with tetrahydrofuran as eluent, polystyrene standard;

[0033] Size exclusion chromatography (SEC = size exclusion chromatography).

[0034] The vulcanizable rubber mixture according to the invention comprises one or more fillers selected from the group consisting of silicas. In the context of the present invention, the term "silica" commonly used in the industry is used, although the corresponding compounds are sometimes also referred to as "silica" in reference to the English term. For those skilled in the art in the rubber processing industry, this historically determined term refers to amorphous, i.e. non-crystalline, silicon dioxide, in particular so-called pyrogenic silicon dioxide and precipitated silicon dioxide. In other words, this is a vulcanizable rubber mixture according to the invention, comprising one or more fillers selected from the group consisting of pyrogenic silicon dioxide and precipitated silicon dioxide, particularly preferably precipitated silicon dioxide.

[0035] In principle, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more fillers have a nitrogen surface area (BET surface area) according to DIN ISO 9277:2014-01 in the range from 35 to 400 m 2 / g, preferably in the range of 35 to 350 m 2 / g, particularly preferably in the range of 85 to 320 m 2 / g, most preferably in the range of 120 to 235 m 2 / g. Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more fillers have a CTAB surface area according to ASTM D 3765-03 in the range of 30 to 400 m 2 / g, preferably in the range of 30 to 330 m 2 / g, particularly preferably in the range of 80 to 300 m 2 / g, most preferably in the range of 115 to 200 m 2 / g.

[0036] With regard to the usable amounts of filler, the inventors have found that the vulcanizable rubber mixtures according to the invention advantageously exhibit excellent results even for high filler contents. However, in the inventors' estimation, the solution identified within the scope of the present invention exhibits the greatest advantages particularly at medium filler contents. Accordingly, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises the one or more fillers in a combined mass fraction in the range from 5 to 250 phr, preferably in the range from 20 to 180 phr, particularly preferably in the range from 30 to 140 phr, and most preferably in the range from 40 to 110 phr.

[0037] In addition to the silicas used according to the invention, further fillers may also be present, which allows for a specific adaptation of the properties of the vulcanizable rubber mixture. A vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises one or more further fillers selected from the group consisting of carbon black, aluminum hydroxide, titanium dioxide, magnesium oxide, and phyllosilicates, wherein the combined mass fraction of the further fillers is preferably in the range from 0.1 to 100 phr, particularly preferably in the range from 0.5 to 50 phr. The carbon black used is preferably a carbon black which has an iodine adsorption number according to ASTM D 1510 of 30 to 250 g / kg, preferably 30 to 180 g / kg, particularly preferably 40 to 130 g / kg, and a DBP number according to ASTM D 2414 of 30 to 200 ml / 100 g, preferably 70 to 200 ml / 100 g, particularly preferably 90 to 200 ml / 100 g.

[0038] The vulcanizable rubber mixture according to the invention comprises at least one polyetheramine of a specific structure. Polyetheramines are generally known to those skilled in the art. They are polyether polyols whose terminal hydroxyl groups have been converted into amino groups in an amination reaction, thus obtaining polyamines. In the case of the amination of the particularly preferred linear, i.e. unbranched, polyetherdiols, the polyetheramines are correspondingly diamines of a polyalkylene glycol. The underlying polyetherdiols are preferably prepared from alkylene oxides, for example butylene oxide, ethylene oxide, or propylene oxide. Polyetheramines are commercially available, in particular from Huntsman, for example under the trade names Jeffamine D-230, ED-600, ED-900, or EDR-148.

[0039] The polyetheramine to be used according to the invention is selected from the group consisting of polyetheramines of the formula I):

[0040] I) R 1 R 2 N - (R 5 ) m - X - R 6 - NR 3 R 4 , where R 1 , R 2 , R 3 and R 4 are independently hydrogen or either branched or unbranched hydrocarbon radicals having 1 to 10 C atoms, where m is 0 or 1, where R 5 and R 6 are independently either branched or unbranched hydrocarbon chains having 1 to 10 C atoms, where X is a polyether chain of the formula II):

[0041] II) - (CHR 7i - CHR 8 ' - O)x -, where x is in the range of 2 to 30, where R 7i and R 8iin each monomer unit i, independently of one another and independently of the other monomer units of the polyether chain, are hydrogen or hydrocarbon radicals with 1 or 2 C atoms,

[0042] The organic residues R 1 , R 2 , R 3 and R 4 define the residues of the amino groups of the diamine and result, in particular, from the substances used in the amination reaction during production. In accordance with the expert understanding, these residues are in principle independent of each other, which means that, for example, R 1 can be hydrogen, even if R 2 is a hydrocarbon radical. In this respect, a vulcanizable rubber mixture according to the invention is preferred, wherein R 1 , R 2 , R 3 and R 4are independently hydrogen or either branched or unbranched, preferably unbranched, hydrocarbon radicals having 1 to 5 C atoms, preferably having 2 to 5 C atoms. Particularly preferred is a vulcanizable rubber mixture according to the invention, wherein at least one of the radicals R 1 and R 2 and / or one of the residues R 3 and R 4 , hydrogen. A vulcanizable rubber mixture according to the invention is particularly preferred, wherein the radicals R 1 and R 3 and / or the residues R 2 and R 4 are identical. A vulcanizable rubber mixture according to the invention is particularly preferred, wherein the radicals R 1 , R 2 , R 3 and R 4 are hydrogen.

[0043] One of the amino groups can be attached to the polyether chain X either directly (m = 0) or via a hydrocarbon chain (m = 1). Due to the preparation from alkylene oxides, in preferred polyetheramines one of the amino groups is attached directly to the polyether chain X (m = 0), whereas the other amino group is attached via a hydrocarbon chain R 6 which would ultimately be the last building block of the polyether chain, but which, as a result of the amination, no longer has an oxygen atom and can therefore no longer be assigned to the polyether chain X. Thus, a vulcanizable rubber mixture according to the invention is preferred, where R 5 and R 6are independently of one another either branched or unbranched hydrocarbon chains having 1 to 5 C atoms, preferably having 2 or 3 C atoms. Particularly preferred in this respect is a vulcanizable rubber mixture according to the invention, where m = 0, where R 6 preferably a branched or unbranched hydrocarbon chain with 2 or 3 C atoms, particularly preferably a branched or unbranched hydrocarbon chain with 3 C atoms.

[0044] The polyether chain X comprises x repeating units. A vulcanizable rubber mixture according to the invention is preferred, where x is in the range from 2 to 15.

[0045] In each building unit of the polyether chain X, ie in the various monomer units, which are identified here by the running number i, which runs from i = 1 to i = x, R 7i and R 8i fundamentally independent of each other, both R 7i and R 8iin each monomer unit as well as all R 7i or all R 8i in the polyether chain.

[0046] Due to the fundamental advantages of comparatively short-chain alkylene oxides, a vulcanizable rubber mixture according to the invention is preferred, wherein R 7i and R 8i in each monomer unit i, independently of one another and independently of the other monomer units of the polyether chain, are hydrogen or methyl groups. A vulcanizable rubber mixture according to the invention is particularly preferred, wherein in each monomer unit i at least one of the radicals R 7i and R 8i Hydrogen is.

[0047] The person skilled in the art understands that the nature of the residues R 7i and R 8idepends in particular on the chemical nature of the compounds used in the preparation, in particular the alkylene oxides used, whereby more complex polyetheramines can be obtained in particular when different alkylene oxides are mixed together during the preparation.

[0048] According to the inventors, a vulcanizable rubber mixture according to the invention is preferred, wherein the polyether chain comprises one or more first monomer units i1 of the formula IV):

[0049] IV) - (CHR 7i - CH2- 0) -, where R 7i is preferably identical for all first monomer units h, where R 7i particularly preferably for all first monomer units h is a methyl group, and / or wherein the polyether chain comprises one or more second monomer units i2 of formula V):

[0050] V) - (CH2- CH2- 0) -, and / or wherein the polyether chain comprises one or more third monomer units of the formula VI):

[0051] VI) - (CH2- CHR 8 ' - 0) -, where R 8i preferably for all third monomer units is identical, where R 8i particularly preferably for all third monomer units is a methyl group, wherein the polyether chain preferably consists of these monomer units.

[0052] With regard to these monomer units, vulcanizable rubber mixtures according to the invention are generally preferred, wherein the number of first monomer units h in the polyether chain xi is in the range from 1 to 7, preferably in the range from 2 to 6, particularly preferably in the range from 2 to 5, and / or wherein the number of second monomer units i2 in the polyether chain x2 is in the range from 1 to 15, preferably in the range from 2 to 12, particularly preferably in the range from 3 to 10, and / or wherein the number of third monomer units is in the polyether chain xs is in the range from 1 to 7, preferably in the range from 2 to 6, particularly preferably in the range from 2 to 5. In this respect, a vulcanizable rubber mixture according to the invention is particularly preferred, wherein the combined number of the first monomer units h and the third monomer units is in the polyether chain X1 / 3 is in the range from 2 to 10, preferably in the range from 3 to 7.In this respect, very particular preference is given to a vulcanizable rubber mixture according to the invention, wherein the polyether chain preferably consists of more than 50%, particularly preferably more than 75%, particularly preferably substantially entirely, of first monomer units h, wherein the number of first monomer units h in the polyether chain xi is in the range from 1 to 5, preferably in the range from 2 to 4. Corresponding polyetheramines are commercially available, for example, under the trade name Jeffamine D-230, wherein xi is about 2.5.

[0053] Additionally or alternatively, particularly preferred is a vulcanizable rubber mixture according to the invention with mixed polyether chains, ie wherein the polyether chain comprises two or more, preferably three or more, monomer units selected from the group consisting of first monomer units h, second monomer units i2 and third monomer units is, wherein the polyether chain preferably consists of these monomer units. Relevant for most applications are vulcanizable rubber mixtures according to the invention wherein the two or more monomer units are distributed at least partially randomly, preferably completely randomly, in the polyether chain.

[0054] For mixed polyether chains, very particular preference is given to a vulcanizable rubber mixture according to the invention, wherein the combined number of the first monomer units h and the third monomer units is in the polyether chain X1 / 3 is in the range from 2 to 5 and wherein the number of the second monomer units i2 in the polyether chain X2 is in the range from 7 to 12. Corresponding polyetheramines are commercially available, for example, under the trade name Jeffamine ED-600, wherein X2 is about 9 and X1 / 3 is about 3.6.

[0055] For mixed polyether chains, additionally or alternatively, a vulcanizable rubber mixture according to the invention is also particularly preferred, wherein the combined number of the first monomer units h and the third monomer units i in the polyether chain X1 / 3 is in the range from 4 to 8, and wherein the number of the second monomer units i2 in the polyether chain X2 is in the range from 10 to 15. Corresponding polyetheramines are commercially available, for example, under the trade name Jeffamine ED-900, wherein X2 is about 12.5 and X1 / 3 is about 6.

[0056] The inventors consider the use of polyetheramines, typical representatives of which are the commercial products Jeffamine D-230 and ED-600, to be particularly preferred for solving the problem.

[0057] Accordingly, a vulcanizable rubber mixture according to the invention is particularly preferred, wherein the one or more polyetheramines are selected from the group consisting of:

[0058] - polyetheramines of formula VII):

[0059] VII) H2N - (CH(CH3) - CH2-O)xi - CH2CH(CH3) - NH2, where xi is in the range from 2 to 6, preferably in the range from 2 to 5, particularly preferably in the range from 2 to 4, most particularly preferably in the range from 2 to 3, and

[0060] - polyetheramines of formula VIII):

[0061] VIII) H2N - X - CH2CH(CH3) - NH2, where X is a polyether chain consisting of two or more monomer units selected from the group consisting of first monomer units i of formula IVb):

[0062] IVb) - (CH(CH3) - CH2 - O) - second monomer units i2b of formula Vb): Vb) - (CH2 - CH2 - O) and third monomer units i3b of formula VIb):

[0063] VIb) - (CH2- CH(CH3) - O) - wherein the combined number of the first monomer units hb and the third monomer units i3b in the polyether chain x / 3b is in the range of 2 to 5, wherein the number of the second monomer units i2b in the polyether chain X2b is in the range of 8 to 10.

[0064] Basically, preference is given to the production or

[0065] The polyetheramines can also be prepared using a vulcanizable rubber mixture according to the invention, wherein the one or more polyetheramines can be prepared by polymerizing an alkylene oxide followed by amination, wherein the alkylene oxide is preferably selected from the group consisting of butylene oxide, ethylene oxide, propylene oxide, and mixtures of these compounds, preferably propylene oxide. Additionally or alternatively, a vulcanizable rubber mixture according to the invention is also particularly preferred, wherein the one or more polyetheramines are saturated compounds.

[0066] Comparatively short-chain compounds are preferably used as polyetheramines. Particular preference is given to a vulcanizable rubber mixture according to the invention in which the one or more polyetheramines have a weight-average molecular weight in the range from 100 to 800 g / mol, preferably in the range from 130 to 650 g / mol, particularly preferably in the range from 190 to 400 g / mol.

[0067] To further optimize the properties of the vulcanizable rubber mixture according to the invention or of the vulcanizates producible therefrom, various polyetheramines can be combined. The inventors consider combinations of preferred polyetheramines particularly advantageous, as can be achieved, for example, by combining the commercial products Jeffamine D-230 and ED-600. Accordingly, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises two or more different polyetheramines.

[0068] Regardless of the exact chemical nature of the polyetheramines, the inventors have succeeded in identifying particularly advantageous mass fractions of these components with which the above-described objects can be achieved particularly well. A vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises the one or more polyetheramines in a combined mass fraction in the range of 0.2 to 8 phr, preferably in the range of 0.4 to 6 phr.

[0069] The vulcanizable rubber mixture according to the invention further comprises one or more liquid polybutadienes, wherein the one or more liquid polybutadienes have a number-average molar mass Mn, measured by GPC, in the range from 500 to 20,000 g / mol. The liquid polybutadienes are polymers based on butadiene. Corresponding liquid polybutadienes are known in principle to those skilled in the art and are commercially available. Information on the technological background is disclosed, for example, in EP 3303004 A1. The skilled person understands that the criterion "liquid" results from the stated number-average molar mass. In this respect, the term "liquid" means that the polybutadiene is liquid at a temperature of 23°C and 100 kPa.In accordance with the expert understanding, a compound is in any case considered to be liquid if its dynamic viscosity at 23 °C is 20 Pa s or less, preferably 10 Pa s or less, measured according to DIN 53211:1987-06.

[0070] Although the liquid polybutadienes are polymers of butadiene, as is the case, for example, with butadiene rubber, the skilled person can easily distinguish the liquid polybutadiene from the rubbers because the average molar mass is significantly lower than that of rubbers. In this respect, the skilled person understands that the liquid polybutadienes are not considered high-molecular-weight rubbers when calculating the mass fractions in phr. In this respect, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more liquid polybutadienes have a number-average molar mass Mn, measured by GPC, in the range from 1000 to 15000 g / mol, preferably in the range from 2000 to 12000 g / mol, particularly preferably in the range from 3000 to 9000 g / mol.

[0071] Based on the experiments conducted, the inventors have succeeded in identifying particularly advantageous mass fractions for the liquid polybutadiene. Preferred is a vulcanizable rubber mixture according to the invention, wherein the vulcanizable rubber mixture comprises the one or more liquid polybutadienes in a combined mass fraction in the range from 1 to 70 phr, preferably in the range from 2 to 50 phr, particularly preferably in the range from 3 to 40 phr, and very particularly preferably in the range from 4 to 35 phr. Additionally or alternatively, preferred is also a vulcanizable rubber mixture according to the invention, wherein the mass fraction of the one or more liquid polybutadienes, based on the total mass of all plasticizers in the vulcanizable rubber mixture, is 30% or more, preferably 60% or more, particularly preferably 90% or more, and very particularly preferably substantially 100%.

[0072] The inventors have succeeded in identifying particularly preferred liquid polybutadienes with which vulcanizable rubber mixtures according to the invention with particularly positive property profiles can be obtained.

[0073] Firstly, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more liquid polybutadienes have a glass transition temperature Tg according to DSC in the range from -95 to -30 °C, preferably in the range from -90 to -40 °C. The glass transition temperature Tg is determined in the context of the present invention in the usual way by means of 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 specifications, sample in an aluminum crucible with an aluminum lid, cooling to temperatures below -120 °C at 10 °C / min).

[0074] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the one or more liquid polybutadienes have a vinyl content in the range from 10 to 40%, preferably in the range from 15 to 35%, particularly preferably in the range from 20 to 40%, and / or wherein the one or more liquid polybutadienes have a 1,4-trans content in the range from 40 to 70%, preferably in the range from 45 to 60%. The corresponding proportions can be determined, for example, by means of 13 Determine C-NMR.

[0075] The experiments have shown that the use of liquid polybutadienes modified along the chain and / or at the end, in particular silicon-modified liquid polybutadienes, as disclosed, for example, in EP 3303004 A1, is particularly preferred. Such silicon-modified liquid polybutadienes have proven particularly suitable, particularly in average mass fractions in the range of 1 to 15 phr, preferably in the range of 2 to 12 phr, for combining excellent abrasion resistance with particularly advantageous mechanical properties.Accordingly, a vulcanizable rubber mixture according to the invention is particularly preferred, wherein the one or more liquid polybutadienes are selected from the group consisting of modified liquid polybutadienes, preferably organosilicon-modified liquid polybutadienes, particularly preferably terminally organosilicon-modified liquid polybutadienes. A vulcanizable rubber mixture according to the invention is particularly preferred, wherein the one or more liquid polybutadienes are selected from the group consisting of organosilicon-modified liquid polybutadienes modified with a radical of the formula A1):.

[0076] A1 ) (R a R b R c ) Si where R a , R b and R c are independently branched or unbranched alkoxy groups or alkyl groups having 1 to 10 C atoms, where at least one of the radicals R a , R band R c is an alkoxy group. Particularly preferred in this respect is a vulcanizable rubber mixture according to the invention, wherein the one or more liquid polybutadienes are selected from the group consisting of organosilicon-modified liquid polybutadienes modified with a radical of the formula A2):

[0077] A2) (R a R b R c ) Si - R d - R e - where R a , R b and R c are independently branched or unbranched alkoxy groups or alkyl groups having 1 to 10 C atoms, where at least one of the radicals R a , R b and R c is an alkoxy group, where R d is a branched or unbranched hydrocarbon chain with 1 to 10 C atoms and where R eis a functional group preferably selected from the group consisting of ester, ether, urethane, urea, amine, amide, thioether and thioester.

[0078] In addition to the diene rubbers, the fillers, the polyetheramines and the liquid polybutadienes, other typical components can be used in the vulcanizable rubber mixtures according to the invention, which serve, for example, to influence the physicochemical properties, e.g. the processing and vulcanization properties, of the vulcanizable rubber mixtures or to optimize the mechanical properties of the vulcanizates produced therefrom.

[0079] In this respect, preference is given firstly to a vulcanizable rubber mixture according to the invention, wherein the vulcanizable rubber mixture comprises one or more further additives, wherein the further additives are preferably selected from the group consisting of reinforcing resins, coupling agents and further plasticizers, wherein the vulcanizable rubber mixture comprises the further additives preferably in a combined mass fraction in the range from 10 to 100 phr, preferably in the range from 20 to 80 phr, particularly preferably in the range from 30 to 60 phr.

[0080] An example of this is a vulcanizable rubber mixture according to the invention, wherein the reinforcing resins are selected from the group consisting of resorcinol-formaldehyde resins, in particular resorcinol-hexamethoxymethylmelamine resins (HMMM) or resorcinol-hexamethylenetetramine resins (HEXA), and modified phenolic resins. Those skilled in the art of rubber processing are readily able to distinguish resins from diene rubbers, which in practice is done primarily by means of the average molecular weight. By way of example, a vulcanizable rubber mixture according to the invention is provided, wherein the one or more further resins have a weight-average molecular mass Mw, measured by GPC, in the range from 200 to 50,000 g / mol, preferably in the range from 400 to 40,000 g / mol, particularly preferably in the range from 600 to 30,000 g / mol, very particularly preferably in the range from 800 to 20,000 g / mol.

[0081] Also exemplary is a vulcanizable rubber mixture according to the invention, wherein the coupling agents are selected from the group consisting of 3-mercaptopropyltriethoxysilane, 3-thiocyanatopropyltrimethoxysilane and 3,3'-bis(triethoxysilylpropyl)polysulfides having 2 to 8 sulfur atoms, wherein the vulcanizable rubber mixture preferably comprises the coupling agents in a combined mass fraction in the range of 0.2 to 30 phf, preferably in the range of 1 to 15 phf.

[0082] A vulcanizable rubber mixture according to the invention is also exemplary, wherein the further plasticizers are selected from the group consisting of mineral oils, synthetic plasticizers, fatty acids, fatty acid derivatives, plasticizer resins, factices, glycerides, terpenes, biomass-to-liquid oils (BTL oils) and rubber-to-liquid oils (RTL oils), wherein the vulcanizable rubber mixture comprises the plasticizers preferably in a combined mass fraction in the range from 1 to 100 phr, preferably in the range from 10 to 80 phr, particularly preferably in the range from 20 to 60 phr.

[0083] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises one or more further additives, wherein the further additives are preferably selected from the group consisting of methylene donors, ageing inhibitors, 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), activators, for example zinc oxide and fatty acids, waxes, mastication aids, for example 2,2'-dibenzamidodiphenyl disulfide (DBD) and processing aids.Preference is given to a vulcanizable rubber mixture according to the invention, wherein the vulcanizable rubber mixture comprises the further additives in a combined mass fraction in the range from 0.1 to 20 phr, preferably in the range from 0.5 to 15 phr, particularly preferably in the range from 1 to 10 phr.

[0084] With regard to vulcanization behavior, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises 0.5 to 8.0 phr, preferably 0.8 to 6 phr, particularly preferably 1 to 4 phr, of sulfur. In this respect, a vulcanizable rubber mixture according to the invention is additionally or alternatively preferred, wherein the vulcanizable rubber mixture comprises further vulcanization constituents, wherein the further vulcanization constituents are selected from the group consisting of crosslinkers, vulcanization retarders, and vulcanization accelerators, for example thiazole accelerators, mercapto accelerators, sulfenamide accelerators, thiocarbamate accelerators, thiuram accelerators, thiophosphate accelerators, thiourea accelerators, xanthate accelerators, or guanidine accelerators.

[0085] It is particularly preferred to omit guanidine accelerators, in particular diphenylguanidine. Accordingly, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises 2 phr or less, preferably 1 phr or less, particularly preferably 0.5 phr or less, very particularly preferably essentially 0 phr, of guanidine accelerators, in particular diphenylguanidine.

[0086] Vulcanizates or rubber products can be produced in the usual way from the vulcanizable rubber mixtures according to the invention. The corresponding process for producing a vulcanizate or a rubber product comprises, in addition to producing the vulcanizable rubber mixture according to the invention, for example, the additional step: x) vulcanizing the vulcanizable rubber mixture according to the invention, preferably as part of a rubber green body, particularly preferably an unvulcanized green vehicle tire, to obtain a vulcanizate, preferably as part of a rubber product, preferably a pneumatic vehicle tire. The vulcanizable rubber mixture according to the invention is vulcanized, for example, by the process customary in the tire industry, for example by sulfur-based crosslinking.

[0087] The invention accordingly also relates to a vulcanizate that can be produced or is produced by vulcanizing a vulcanizable rubber mixture according to the invention. Preferred in this respect is a vulcanizate according to the invention that can be produced by vulcanization at a temperature in the range of 130 to 200°C, preferably in the range of 150 to 180°C.

[0088] The invention accordingly also relates to a rubber product comprising the vulcanizate according to the invention. An example of a rubber product according to the invention is one in which the rubber product is selected from the group consisting of shoe soles, belts, hoses, conveyor belts, and straps. However, for essentially all cases, a rubber product according to the invention is preferred, wherein the rubber product is a vehicle tire, preferably a pneumatic vehicle tire, wherein the pneumatic vehicle tire preferably comprises the vulcanizate according to the invention in the tread.

[0089] Finally, the use of a vulcanizable rubber mixture according to the invention and / or a vulcanizate according to the invention in the production of rubber products, in particular vehicle tires, is also disclosed.

[0090] In the following, the invention and preferred embodiments of the invention are further explained and described with reference to experiments.

[0091] A. Production of vulcanizable rubber compounds:

[0092] The vulcanizable rubber compounds were produced according to the process customary in the rubber industry under standard conditions in three stages in a laboratory tangential mixer, in which a base mixture is first produced in one or more mixing stages, which contains all components except the vulcanization system (sulfur and vulcanization-influencing substances), from which the finished mixture is then produced by adding the vulcanization system.

[0093] The substances used are listed in Table 1.

[0094] Table 1 - Substances used

[0095] Test specimens were produced from the vulcanizable rubber compounds by vulcanization according to tos - two (measured on a moving die rheometer according to ASTM D 5289-19 / ISO 6502) under pressure at 160 to 170 °C and material properties typical for the rubber industry were determined on the test specimens produced in this way using the test methods specified under point B.

[0096] B. Determination of the physico-chemical properties of the vulcanizates:

[0097] The following physico-chemical properties were determined on the vulcanizable rubber compounds or the vulcanizates produced from them using the methods listed in Table 2:

[0098] Table 2 - Determination methods used

[0099] C. Test series:

[0100] Twelve vulcanizable rubber compounds were prepared, the composition of which is given in Tables 3 and 4. Table 3 - Vulcanizable Rubber Compounds - Part 1 (all values ​​in phr)

[0101] Table 3 - Vulcanizable rubber compounds - Part 2 (all values ​​in phr)

[0102] The mass fraction of the polyetheramines was adjusted in each case to ensure a constant amount of material was introduced. The material properties determined for the corresponding vulcanizates are summarized in Tables 5 and 6. Table 5 - Material Properties Part 1

[0103] Table 6 - Material properties Part 2

[0104] The results summarized in Tables 5 and 6 show that polyetheramines 1 and 2 exhibit a beneficial acceleration effect, which is reflected in a reduction in t10 and t90 times. This advantageously makes it possible to achieve a favorable acceleration effect and a shorter cure time without the use of DPG.

[0105] Without the liquid polybutadiene, the use of polyetheramine 1 in V2 and polyetheramine 2 in V3 leads to an undesirable decrease in E'(8%) compared to V1, whereas the abrasion remains essentially unchanged and an improvement in the tensile strength is only shown for polyetheramine 2.

[0106] In contrast, samples E1 to E6, which also contain liquid polybutadiene, surprisingly show significantly improved abrasion behavior compared to their respective comparison samples. Samples E1 and E2 also show an improvement in E' (8%), indicating higher stiffness and improved handling. Furthermore, with the addition of polyetheramine, samples E1 to E4 show an improvement in tensile strength in addition to the beneficial improvement in abrasion for both polyetheramines.

[0107] With regard to the surprising improvement in abrasion, the use of organosilicon-modified liquid polybutadiene is particularly advantageous. However, based on the tests, these compounds exhibit a less favorable effect at concentrations of 16 phr and above compared to lower mass fractions regarding E' (8%) and tensile strength. Given the corresponding trade-off, samples E3 and E4 are considered particularly preferable.

[0108] For polyetheramine 1, a particularly favorable increase in HSTE is observed, while this value remains at a comparable level for polyetheramine 2. Samples E1, E3, and E5 accordingly exhibit additionally favorable tear properties on rough road sections. Overall, sample E3 is therefore considered particularly favorable.

Claims

Claims 1. Vulcanizable rubber mixture comprising: a) one or more diene rubbers, b) one or more fillers selected from the group consisting of silicas, c) one or more polyetheramines, in a combined mass fraction in the range of 0.1 to 10 phr, wherein the polyetheramines are selected from the group consisting of polyetheramines of the formula I): I) R 1 R 2 N - (R 5 ) m - X - R 6 - NR 3 R 4 , where R 1 , R 2 , R 3 and R 4 are independently hydrogen or either branched or unbranched hydrocarbon radicals having 1 to 10 C atoms, where m is 0 or 1, where R 5 and R 6 are independently either branched or unbranched hydrocarbon chains having 1 to 10 C atoms, where X is a polyether chain of the formula II): II) - (CHR 7i - CHR8 ' - O)x -, where x is in the range of 2 to 30, where R 7i and R 8i in each monomer unit i, independently of one another and independently of the other monomer units of the polyether chain, are hydrogen or hydrocarbon radicals having 1 or 2 C atoms, and d) one or more liquid polybutadienes, wherein the one or more liquid polybutadienes have a number-average molar mass Mn, measured by GPC, in the range from 500 to 20,000 g / mol.

2. Vulcanizable rubber mixture according to claim 1, wherein the vulcanizable rubber mixture comprises styrene-butadiene rubber as diene rubber, and / or wherein the vulcanizable rubber mixture comprises butadiene rubber as diene rubber, and / or wherein the vulcanizable rubber mixture comprises natural polyisoprene and / or synthetic polyisoprene as diene rubber.

3. A vulcanizable rubber composition according to any one of claims 1 or 2, wherein the vulcanizable rubber composition comprises the one or more fillers in a combined mass fraction in the range of 5 to 250 phr.

4. Vulcanizable rubber mixture according to one of claims 1 to 3, wherein R 7i and R 8i in each monomer unit i, independently of one another and independently of the other monomer units of the polyether chain, are hydrogen or methyl groups.

5. Vulcanizable rubber mixture according to one of claims 1 to 4, wherein the polyether chain comprises one or more first monomer units i1 of the formula IV): IV) - (CHR 7i - CH2- 0) -, and / or wherein the polyether chain comprises one or more second monomer units i2 of formula V): V) - (CH2- CH2- 0) -, and / or wherein the polyether chain comprises one or more third monomer units of the formula VI): VI) - (CH2- CHR 8 ' - 0) 6. Vulcanizable rubber mixture according to one of claims 1 to 5, wherein the one or more polyetheramines are selected from the group consisting of: - polyetheramines of formula VII): VII) H2N - (CH(CH3) - CH2- O)xi - CH2CH(CH3) - NH2, where xi is in the range from 2 to 6, and - polyetheramines of formula VIII): VIII) H2N - X - CH2CH(CH3) - NH2, where X is a polyether chain consisting of two or more monomer units selected from the group consisting of first monomer units i of the formula IIIb): IIIb) - (CH(CH3) - CH2- O) - second monomer units i2b of the formula IVb): IVb) - (CH2- CH2- 0) -, and third monomer units i3b of formula Vb): Vb) - (CH2- CH(CH3) - 0) -, where the combined number of the first monomer units hb and the third monomer units i3b in the polyether chain x / 3b is in the range of 2 to 5, wherein the number of second monomer units i2b in the polyether chain X2b is in the range from 8 to 10.

7. A vulcanizable rubber composition according to any one of claims 1 to 6, wherein the vulcanizable rubber composition comprises the one or more liquid polybutadienes in a combined mass fraction in the range of 1 to 70 phr.

8. Vulcanizable rubber mixture according to one of claims 1 to 7, wherein the one or more liquid polybutadienes are selected from the group consisting of modified liquid polybutadienes, preferably organosilicon-modified liquid polybutadienes.

9. Vulcanizate, producible or produced by vulcanization of a vulcanizable rubber mixture according to one of claims 1 to 8.

10. A rubber product, in particular a pneumatic vehicle tire, comprising a vulcanizate according to claim 9.

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