Vulcanisable rubber mixture, vulcanised material, and rubber product

Abstract

The invention relates to a vulcanisable rubber mixture comprising: a) diene rubbers; b) silicas; and c) specific polyether amines, in a combined mass fraction in the range of 0.1 to 10 phr, the vulcanisable rubber mixture comprising, as a diene rubber, natural polyisoprene in a mass fraction in the range of 25 to 100 phr, and the vulcanisable rubber mixture comprising the one or more fillers in a combined mass fraction of 55 phr or less.

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 rolling properties, in particular an advantageous rolling resistance.

[0012] 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 improved abrasion properties and advantageous robustness, in particular also with regard to improved tear properties on rough roads.

[0013] In particular, it was an object of the present invention to resolve existing conflicts of objectives between the processing properties, the mechanical properties and the rolling properties in the best possible way.

[0014] 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.

[0015] 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.

[0016] The inventors of the present invention have now found that the objects described above can surprisingly be achieved if, in vulcanizable rubber mixtures which, in addition to diene rubber and silica, additionally comprise certain mass fractions of specific polyetheramines, a maximum content of silica is provided and natural rubber is used as the diene rubber, as defined in the claims.

[0017] 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.

[0018] Such embodiments, which are referred to below as preferred, are combined in particularly preferred embodiments with features of other embodiments referred to as preferred. Combinations of two or more of the embodiments referred to below as particularly preferred are therefore very particularly preferred. Likewise preferred are embodiments in which a feature of an embodiment referred to as preferred to any extent is combined with one or more further features of other embodiments referred to as preferred to any extent. Features of preferred vulcanizates, rubber products and uses arise from the features of preferred vulcanizable rubber mixtures. Insofar as specific amounts orWhere both the proportions of this mixture component and preferred embodiments of the mixture component are disclosed, 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

[0019] 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.

[0020] 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, and 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):

[0021] 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 of one another 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- CHR 8 ' - 0)x -, where x is in the range from 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, wherein the vulcanizable rubber mixture comprises, as diene rubber, natural polyisoprene in a mass fraction in the range of 25 to 100 phr, and wherein the vulcanizable rubber mixture comprises the one or more fillers in a combined mass fraction of 55 phr or less.

[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 compound based on the mass of the high molecular weight rubbers present in the rubber compound (weight-average molecular weight Mw according to GPC greater than 60,000 g / mol), whereby the combined mass fraction of these high molecular weight rubbers in the rubber compound 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 compound.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 rubbers obtained by (co)polymerization of dienes and / or cycloalkenes and thus have C=C double bonds either in the main chain or in the side groups.

[0027] According to the invention, the vulcanizable rubber mixture comprises natural rubber as the diene rubber. Natural rubber is well known to those skilled in the art in the field of tire production and is commercially available. Natural rubber is a natural polyisoprene, in particular a cis-1,4 polyisoprene in which the cis-1,4 content in the natural rubber is greater than 99% by weight. It can be seen as an advantage of the vulcanizable rubber mixture according to the invention that, in addition to natural rubber, other diene rubbers can be present and these are very flexible in terms of selection, so that, in principle, all diene rubbers customary in the industry can be used in combination. In the opinion of the inventors, however, 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 natural polyisoprene and 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 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.

[0028] With regard to the content of natural polyisoprene, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises natural polyisoprene as diene rubber in a mass fraction of 50 phr or more, preferably 60 phr or more, particularly preferably 65 phr or more. Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises natural polyisoprene as diene rubber in a mass fraction of 90 phr or less, preferably 80 phr or less.

[0029] To obtain vulcanizable rubber compounds that can be converted into particularly high-performance vulcanizates by vulcanization, BR and IR in particular have proven to be suitable diene rubbers for combination with natural polyisoprene.

[0030] Thus, 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 75 phr, particularly preferably in the range from 5 to 55 phr, very particularly preferably in the range from 10 to 35 phr. The butadiene rubber can, for example, be so-called high-cis or low-cis types, with polybutadiene with a mass-related cis content of 90% or more being referred to as a high-cis type.

[0031] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises synthetic polyisoprene as the diene rubber, preferably in a combined mass fraction in the range from 1 to 75 phr, more preferably in the range from 5 to 55 phr, most preferably in the range from 10 to 35 phr. The synthetic polyisoprene can be either cis-1,4-polyisoprene or 3,4-polyisoprene. However, the use of cis-1,4-polyisoprenes is preferred. Additionally or alternatively, preference is given to a vulcanizable rubber mixture according to the invention, wherein the diene rubber(s) have(s) 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 determination of the number-average orThe weight-average molecular weight is determined in the context of the present invention by means of gel permeation chromatography according to DIN 55672-1: 2016-03 (GPC with tetrahydrofuran as eluent, polystyrene standard;.

[0032] Size exclusion chromatography (SEC = size exclusion chromatography).

[0033] 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.

[0034] 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.

[0035] Regarding the usable amounts of filler, the inventors have found that, in combination with natural rubber and polyetheramines, there is an upper limit for the mass fraction of silica that should not be exceeded to obtain advantageous vulcanizable rubber compounds. Accordingly, the vulcanizable rubber compound comprises a combined mass fraction of 55 phr or less.

[0036] The inventors have found that advantageous property profiles can be achieved, particularly with lower mass fractions of silica. A vulcanizable rubber mixture according to the invention is generally preferred, wherein the vulcanizable rubber mixture comprises the one or more fillers in a combined mass fraction of 50 phr or less, preferably 40 phr or less, particularly preferably 35 phr or less.

[0037] The skilled person understands that the skilled person does not want to choose too low a mass fraction of silica due to its fundamentally positive properties, particularly in tread compounds. Therefore, additionally or alternatively, 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 55 phr, preferably in the range from 10 to 50 phr, particularly preferably in the range from 15 to 45 phr, and most preferably in the range from 20 to 40 phr. The inventors' experiments show that for certain mass fractions of silica in combination with certain mass fractions of natural polyisoprene, particularly advantageous properties of the vulcanizates are obtained.Preferred is a vulcanizable rubber mixture according to the invention, i) wherein the vulcanizable rubber mixture comprises the one or more fillers in a combined mass fraction in the range of 40 to 50 phr and wherein the vulcanizable rubber mixture comprises natural polyisoprene in a mass fraction in the range of 60 to 80 phr, or ii) wherein the vulcanizable rubber mixture comprises the one or more fillers in a combined mass fraction in the range of 20 to 40 phr and wherein the vulcanizable rubber mixture comprises natural polyisoprene in a mass fraction in the range of 90 to 100 phr.

[0038] Additionally or alternatively, a vulcanizable rubber mixture according to the invention is particularly preferred, wherein the combined mass fraction of natural polyisoprene and the one or more fillers is in the range from 30 to 150 phr, preferably in the range from 60 to 140 phr, particularly preferably in the range from 90 to 135 phr.

[0039] 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.

[0040] According to the inventors' assessment, particularly advantageous properties arise in combination with carbon black as an additional filler. A vulcanizable rubber mixture according to the invention is preferred, wherein the vulcanizable rubber mixture comprises carbon blacks, preferably in a combined mass fraction of 1 phr or more, preferably 2 phr or more.

[0041] Particularly preferably, the silica and carbon black contents are coordinated. A carbon black-containing vulcanizable rubber mixture according to the invention is preferred for this purpose, wherein the combined mass fraction of all fillers, the fillers to be used according to the invention, and the additional fillers in the vulcanizable rubber mixture is in the range of 30 to 80 phr, preferably in the range of 40 to 70 phr. Particularly preferred in this respect is a vulcanizable rubber mixture wherein the combined mass fraction of the silicas is in the range of 30 to 75%, preferably in the range of 35 to 70%, based on the total mass of all fillers.

[0042] 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.

[0043] 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.

[0044] The polyetheramine to be used according to the invention is selected from the group consisting of polyetheramines of the formula I):

[0045] 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):

[0046] 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,

[0047] 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 4independently of one another hydrogen or either branched or unbranched, preferably unbranched, hydrocarbon radicals having 1 to 5 C atoms, preferably with

[0048] 2 to 5 C atoms. A vulcanizable rubber mixture according to the invention is particularly preferred, 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.

[0049] 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

[0050] 3 C atoms. 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.

[0051] In each building block 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.

[0052] 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.

[0053] 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.

[0054] 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):

[0055] 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):

[0056] V) - (CH2- CH2- 0) and / or wherein the polyether chain comprises one or more third monomer units of the formula VI):

[0057] 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.

[0058] 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.

[0059] 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.

[0060] 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.

[0061] 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.

[0062] 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 i1 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, where x2 is about 12.5 and xi / 3 is about 6.

[0063] 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.

[0064] 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:

[0065] - polyetheramines of formula VII):

[0066] 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

[0067] - polyetheramines of formula VIII):

[0068] 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):

[0069] IVb) - (CH(CH3) - CH2- O) - second monomer units i2b of formula Vb):

[0070] Vb) - (CH2- CH2- 0) -, and third monomer units i3b of the formula Vlb):

[0071] VIb) - (CH2 - CH(CH3) - O) - wherein the combined number of the first monomer units hb and the third monomer units isb 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.

[0072] With regard to the preparation or producibility of the polyetheramines, a vulcanizable rubber mixture according to the invention is also preferred, wherein the one or more polyetheramines are producible 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.

[0073] 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.

[0074] 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 to be 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. Regardless of the precise chemical nature of the polyetheramines, the inventors have succeeded in identifying particularly advantageous mass fractions of these components with which the objects described above can be achieved particularly well.Preferred is a vulcanizable rubber mixture according to the invention, wherein the vulcanizable rubber mixture comprises the one or more polyetheramines in a combined mass fraction in the range from 0.2 to 8 phr, preferably in the range from 0.4 to 6 phr.

[0075] In addition to the diene rubbers, the fillers and the polyetheramines, other typical components can be used in the vulcanizable rubber mixtures according to the invention, which serve, for example, to influence the physico-chemical properties, e.g. the processing and vulcanization properties, of the vulcanizable rubber mixtures or to optimize the mechanical properties of the vulcanizates that can be produced therefrom.

[0076] 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 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.

[0077] 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.

[0078] 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.

[0079] Also exemplary is a vulcanizable rubber mixture according to the invention, wherein the 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 preferably comprises the plasticizers 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.

[0080] 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.

[0081] 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.

[0082] 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. 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.

[0083] 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.

[0084] 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.

[0085] 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. 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. The invention and preferred embodiments of the invention are further explained and described below with reference to experiments.

[0086] A. Production of vulcanizable rubber compounds:

[0087] The vulcanizable rubber compounds were manufactured according to the usual process in the rubber industry under the usual

[0088] Conditions in three stages in a laboratory tangential mixer, in which a base mixture is initially 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 subsequently produced by adding the vulcanization system.

[0089] The substances used are listed in Table 1.

[0090] Table 1 - Substances used

[0091] 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.

[0092] B. Determination of the physico-chemical properties of the vulcanizates:

[0093] 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:

[0094] Table 2 - Determination methods used

[0095] C. Test series:

[0096] Ten vulcanizable rubber compounds were prepared, the composition of which is given in Table 3. Table 3 - Vulcanizable rubber compounds (all values ​​in phr)

[0097]

[0098] The material properties determined for the corresponding vulcanizates are summarized in Table 4.

[0099] Table 4 - Material properties

[0100] The results summarized in Table 4 demonstrate that the polyetheramine exhibits a beneficial acceleration effect, 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.

[0101] For samples E1 to E4, a favorable property profile is obtained with regard to the properties investigated, whereas higher silica contents adversely affect abrasion.

[0102] In particular, in samples E1 to E4, the Payne effect, which is investigated by E'(0.15%)-E'(8%) and G'(1%)-G'(100%), is not deteriorated, and for E2 and E3 it is also improved, indicating that these vulcanizates show improved rolling resistance.

[0103] Surprisingly, samples E2 and E4 also show improved abrasion compared to the respective comparison samples.

[0104] In addition, samples E2 and E4 show a favorable improvement in tear resistance compared to their respective control samples as an indicator of better robustness.

[0105] In addition, all polyetheramine-containing samples show an increase in high-speed tear energy (HSTE) compared to their control samples, which is an indicator of improved tear properties on rough roads or, in general, of a higher robustness of the compound.

[0106] In summary, samples E2 and E4 are considered to be particularly advantageous, with sample E2 in particular having a particularly advantageous property profile.

[0107] D. Supplementary series of experiments:

[0108] To test the compatibility of the vulcanized rubber compounds with various reinforcing resins, Experiments V1 and E1 were conducted in five sub-experiments in the presence of specific reinforcing resins and investigated for their t10 / t90 values. In each case, 5 phr of a reinforcing resin and 1.25 phr of hexamethoxymethylmelamine (65%) were used. The reinforcing resins used were i) phenol novolak resin, ii) resorcinol, iii) resorcinol-formaldehyde novolak resin, iv) phenol-formaldehyde urethane novolak resin, and v) resorcinol-formaldehyde styrene novolak resin. The acceleration effect was improved compared to DPG for i), iii), iv), and v) and remained at a comparable level for ii).

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, and 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, wherein the vulcanizable rubber mixture comprises natural polyisoprene as diene rubber in a mass fraction in the range from 25 to 100 phr, and wherein the vulcanizable rubber composition comprises the one or more fillers in a combined mass fraction of 55 phr or less.

2. Vulcanizable rubber mixture according to claim 1, wherein the vulcanizable rubber mixture comprises butadiene rubber as diene rubber, and / or wherein the vulcanizable rubber mixture comprises 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 55 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 - O) - and / or wherein the polyether chain comprises one or more third monomer units i3 of formula VI): VI) - (CH2 - CHR8 ' - 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) - wherein the combined number of the first monomer units hb and the third monomer units isb 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.

7. Vulcanizable rubber mixture according to one of claims 1 to 6, wherein the combined mass fraction of natural polyisoprene and the one or more fillers is in the range of 30 to 150 phr.

8. Vulcanizable rubber mixture according to one of claims 1 to 7, wherein the vulcanizable rubber mixture comprises carbon black as a further filler.

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.

Images