Vulcanizable rubber mixture and vulcanized material with improved rolling properties

Abstract

The present invention relates to a vulcanizable rubber compound comprising: a) one or more diene rubbers, b) one or more fillers selected from the group consisting of fillers having free OH groups at the filler surface, c) one or more silicone-modified resins, and d) combined parts by weight of one or more plasticizer oils in the range of 1 to 60 phr.

Description

Field of the Invention

[0001] The present invention relates to a vulcanizable rubber compound, to a vulcanized rubber producible therefrom, and to a rubber product containing the vulcanized rubber. Also disclosed is the use of the corresponding vulcanizable rubber compound / the corresponding vulcanized rubber for improving rolling characteristics in the production of rubber products. Background Art

[0002] The automotive industry is one of the industries that has been facing fundamental challenges since the beginning of the 21st century and has been defined by many technological innovations. The increasing awareness of consumers regarding environmental issues such as emission characteristics and resource efficiency requires new mobility concepts. At the same time, the demand for improved vehicle characteristics and requirements related to driving safety are increasing. Meeting these challenges is not only the task of vehicle manufacturers. In practice, many of these issues are significantly influenced by the characteristics of the tires, and thus the optimization of tire characteristics is an important area of innovation.

[0003] Many relevant characteristics of pneumatic vehicle tires (such as wet grip and abrasion resistance) are closely related to the rubber composition of the tread. Therefore, much research work has focused on optimizing the characteristics of rubber compositions and their additives.

[0004] In recent decades, significant progress has been made in this field. The key innovation here is the at least partial replacement of carbon black fillers with silicon-containing compounds, in particular silica compounds (such as fumed silica or silicates). It has been found that particularly advantageous characteristics can be obtained when the surface of the silicon-containing compound is modified by organosilylation (also known as organosilanization). For this purpose, the silicon-containing compound is reacted with an organosilicon compound, in particular an organoalkoxysilyl organic compound, i.e., a compound having at least one C-O-Si bond and at least one organic group bonded via an Si-C bond. During this chemical reaction (usually a condensation reaction), the modification by the organic group of the organosilicon compound takes place at the interface of the silicon-containing compound. The organic group can specifically influence the compatibility of the filler in the rubber compound and the interaction with the rubber. Here, in many cases it is preferred if the organic group carries a functional group that can crosslink with the rubber compound during the vulcanization process and thus increases the degree of crosslinking in the vulcanized rubber, and thus the organosilicon compound is sometimes also referred to as a so-called silane coupling agent. This principle is disclosed, for example, in DE 2536674 C3 or DE 2255577 A1.

[0005] The concept developed for the modification of silicon-containing compounds was subsequently also applied to resins. For example, WO 2018 / 191187 A1 proposed resins having corresponding filler-reactive groups to likewise permit bonding to the filler, and likewise found a beneficial effect on the physicochemical properties of the vulcanizable rubber blends producible therefrom and of the vulcanized rubber producible by vulcanization thereof. Such resins are sometimes also referred to by the inventors as organosilicon-modified resins.

[0006] Although the use of the corresponding organosilicon-modified resins having filler-reactive groups has fundamental advantages, their use in vulcanizable rubber blends is sometimes also considered disadvantageous. In particular, it is considered disadvantageous in many cases that, although an improvement in the target conflict between rolling resistance and wet grip may have been achieved in many cases, the improvement is still insufficient in many cases. In this regard, when starting from a vulcanizable rubber blend in which an organosilicon-modified resin is used, a solution for improving the target conflict between wet grip and rolling resistance is needed. Summary of the Invention

[0007] The main object of the present invention is to overcome or at least reduce the above-mentioned disadvantages of the prior art.

[0008] In particular, the object of the present invention is to provide a vulcanizable rubber blend and the corresponding vulcanized rubber producible therefrom, which vulcanized rubbers have excellent mechanical properties and optimally solve the target conflict, especially between good wet grip on the one hand and favorable rolling resistance on the other hand. In this regard, it is desirable that the abrasion resistance of these vulcanized rubbers should not decrease or should only decrease negligibly, and ideally even an improvement in abrasion resistance should be achieved.

[0009] In this regard, another object of the present invention is that the vulcanizable rubber blend and the vulcanized rubber to be provided should be producible as far as possible using production methods that are already used today in the field of rubber processing.

[0010] Another object of the present invention is to provide a corresponding rubber product comprising the vulcanized rubber to be provided.

[0011] A secondary object of the present invention is to provide the use of the corresponding vulcanizable rubber blend / corresponding vulcanized rubber for improving the rolling characteristics in the production of rubber products.

[0012] The inventors of the present invention have now recognized that, unexpectedly, when a specific amount of plasticizer oil as defined in the claims is used in a vulcanizable rubber blend comprising an organosilicon-modified resin and a filler having free OH groups at the filler surface (especially a silicon-containing filler), the above objects can be achieved.

[0013] Accordingly, the above object is achieved by the subject matter of the present invention as defined in the claims. Preferred embodiments of the present invention will become apparent from the dependent claims and the discussion below.

[0014] In particularly preferred embodiments, the embodiments hereinafter referred to as preferred are combined with the features of other embodiments also referred to as preferred. Accordingly, combinations of two or more of the embodiments hereinafter referred to as particularly preferred are most particularly preferred. Embodiments in which the features of one embodiment, which is referred to as being preferred to some extent, are combined with one or more further features of other embodiments, which are referred to as being preferred to some extent, are likewise preferred. The features of the preferred vulcanizable rubber compounds, rubber products and uses will become apparent from the features of the preferred vulcanizable rubber blends.

[0015] In the following text, in cases where specific amounts / parts of the blend components (for example, for diene rubbers or organosilicon-modified resins) are not only disclosed, but also preferred embodiments of the blend components are disclosed, the text in particular also discloses the specific amounts / parts of the blend components of these preferred embodiments. Furthermore, it is disclosed that, in the case of the respective specific total amounts / total parts of the blend components, at least some of these blend components can be of the preferred embodiments, and in particular it is also disclosed that the blend components of the preferred embodiments can in turn be present in these specific amounts / parts within these specific total amounts or total parts.

[0016] The present invention relates to a vulcanizable rubber blend comprising:

[0017] a) one or more diene rubbers,

[0018] b) one or more fillers selected from the group consisting of fillers having free OH groups at the filler surface,

[0019] c) one or more organosilicon-modified resins, and

[0020] d) one or more plasticizer oils in a combined weight part range of 1 to 60 phr.

[0021] The vulcanizable rubber blend itself, its typical components, and also typical production methods for obtaining the corresponding vulcanizable rubber blend are well known to those skilled in the art of rubber processing.

[0022] According to standard practice, the components of the vulcanizable rubber compound defined above are each used in the form of "one or more". As is customary in the industry, the expression "one or more" refers to the chemical nature of the corresponding compound, rather than to its molar amount. For example, a vulcanizable rubber compound may contain only SBR as the diene rubber, which would mean that the vulcanizable rubber compound contains a large number of the corresponding molecules.

[0023] In cases where the following text indicates parts by weight, as is customary in the industry, they each indicate in many cases the combined parts by weight of the one or more components, whereby the added parts by weight of the components thus formed satisfy the corresponding standard. The measure phr (parts per hundred parts of rubber by weight) used herein is the customary representation of the amounts used in the formulation of rubber compounds in the rubber industry and represents the parts by weight of the components in the rubber compound based on the weight of the high molecular weight rubber present in the rubber compound (weight average molar mass Mw determined by GPC greater than 60 000 g / mol), where the combined parts by weight of the high molecular weight rubber in the rubber compound correspond to 100 phr.

[0024] The vulcanizable rubber compound according to the invention contains at least one diene rubber. As understood by those skilled in the art, a diene rubber refers to a rubber obtained by the (co)polymerization of a diene and / or a cycloolefin and thus having a C═C double bond in the main chain or side groups. It can be considered an advantage of the vulcanizable rubber compound according to the invention that it has a high degree of flexibility with respect to the diene rubber to be used and can thus in principle use all rubbers customary in the industry. However, in this regard, according to the inventors, it is preferred for the vulcanizable rubber compound according to the invention that 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 halogenated butyl rubber, where 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), and where 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 regard, it is additionally or alternatively also preferred for the vulcanizable rubber compound according to the invention that at least one of these diene rubbers, preferably all of the one or more diene rubbers, are end-group modified and / or chain-modified diene rubbers, preferably end-group modified diene rubbers.

[0025] In particular, it has been found that SBR, BR and IR / NR are suitable diene rubbers for obtaining a vulcanizable rubber compound that can be converted by vulcanization into a particularly effective vulcanized rubber. Thus, first of all, preference is given to a vulcanizable rubber compound according to the invention, in which the vulcanizable rubber compound comprises styrene-butadiene rubber, preferably solution-polymerized styrene-butadiene rubber, as diene rubber, preferably in a combined amount by weight of 30 phr or more, particularly preferably 50 phr or more and most particularly preferably 70 phr or more. Additionally or alternatively, preference is given to a vulcanizable rubber compound according to the invention, in which the vulcanizable rubber compound comprises butadiene rubber as diene rubber, preferably in a combined amount by weight of 30 phr or more, particularly preferably 50 phr or more and most particularly preferably 70 phr or more. Furthermore, additionally or alternatively, preference is given to a vulcanizable rubber compound according to the invention, in which the vulcanizable rubber compound comprises natural polyisoprene and / or synthetic polyisoprene, preferably natural polyisoprene, as diene rubber, preferably in a combined amount by weight in the range from 1 to 40 phr, particularly preferably in the range from 2 to 35 phr and most particularly preferably in the range from 5 to 30 phr.

[0026] Additionally or alternatively, preference is given to a vulcanizable rubber compound according to the invention, in which the one or more diene rubbers have a weight-average molar mass Mw measured by GPC in the range from 200 000 to 5 000 000 g / mol and preferably in the range from 250 000 to 2 500 000.

[0027] In order to optimally adapt the physicochemical / mechanical properties of the vulcanized rubber that can be produced to specific application requirements, it has been found advantageous to mix two or more rubbers together. Thus, preference is given to a vulcanizable rubber compound according to the invention, in which the vulcanizable rubber compound comprises two or more, preferably three or more, different diene rubbers as diene rubber.

[0028] The curable rubber compound according to the invention comprises one or more fillers selected from the group consisting of fillers having free OH groups at the filler surface. Those skilled in the art will understand that these fillers are fillers that can undergo a condensation reaction with the Si-O-R functional groups introduced by the organosilicon-modified resin in the context of the present invention due to the OH functional groups at the filler surface. In addition to other compounds (such as layered silicates like kaolin), fillers having free OH groups at the filler surface are particularly amorphous silica compounds. Thus, the curable rubber compound according to the invention preferably comprises one or more silicon-containing fillers, which are particularly preferably selected from the group consisting of amorphous (i.e., non-crystalline) silica. Among the amorphous silicas, especially the compound that has historically also been called [silicic acid] in the German-speaking world or is called "Silika" [silica] based on English expressions has outstanding importance in the rubber industry, especially in the tire industry, and thus for substantially all cases, using the said as the silicon-containing filler is preferred. Thus, most particularly preferred is the curable rubber compound according to the invention, wherein the one or more silicon-containing fillers are selected from the group consisting of fumed silica and precipitated silica, particularly preferably precipitated silica.

[0029] Fundamentally preferred is the curable rubber compound according to the invention, wherein the one or more silicon-containing fillers have a nitrogen surface area (BET surface area) in the range of 35 to 350 m 2 / g, preferably in the range of 45 to 260 m 2 / g and particularly preferably in the range of 100 to 220 m 2 / g according to DIN ISO 9277:2014-01 and DIN 66132:1975-07. Additionally or alternatively, preferred is the curable rubber compound according to the invention, wherein the one or more silicon-containing fillers have a CTAB surface area in the range of 35 to 350 m 2 / g, preferably in the range of 45 to 300 m 2 / g and particularly preferably in the range of 60 to 280 m 2 / g according to ASTM D 3765-03.

[0030] Regarding the amount of filler that can be used, the inventors have found that even with a high content of filler, the vulcanizable rubber compound according to the invention advantageously exhibits excellent results. However, according to the inventors, the solution determined in the context of the present invention exhibits the greatest advantages especially in the case of a medium filler content. Thus, it is preferred that the vulcanizable rubber compound according to the invention, wherein the vulcanizable rubber compound comprises the one or more fillers having free OH groups at the filler surface, preferably the one or more silica-containing fillers, in a combined weight part in the range of 5 to 250 phr, preferably in the range of 20 to 180 phr, particularly preferably in the range of 30 to 160 phr and most particularly preferably in the range of 40 to 130 phr.

[0031] In addition to the filler having free OH groups at the filler surface (preferably silica-containing filler) to be used according to the invention, there may additionally be present further fillers that do not have free OH groups at the filler surface, thereby allowing a specific adjustment of the properties of the vulcanizable rubber compound. It is preferred that the vulcanizable rubber compound according to the invention, wherein the vulcanizable rubber compound comprises one or more further fillers selected from the group consisting of fillers that do not have free OH groups at the filler surface, and the combined weight part of these further fillers is preferably in the range of 0.1 to 100 phr and particularly preferably in the range of 0.5 to 50 phr.

[0032] In addition to the diene rubber and the filler, and in addition to the resin and the plasticizer oil further characterized below, there may also be used in the vulcanizable rubber compound according to the invention, for example, further typical components for influencing the physicochemical properties (such as processing and vulcanization properties) of the vulcanizable rubber compound or the mechanical properties of the vulcanized rubber producible therefrom.

[0033] In this regard, examples that may be mentioned are vulcanizable rubber blends according to the invention, where the vulcanizable rubber blend comprises one or more additional additives, which are preferably selected from the group consisting of coupling agents, methylene donors, anti-aging agents such as N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (6PPD), N,N'-diphenyl-p-phenylenediamine (DPPD), N,N'-dimethylphenyl-p-phenylenediamine (DTPD), N-isopropyl-N'-phenyl-p-phenylenediamine (IPPD), 2,2,4-trimethyl-1,2-dihydroquinoline (TMQ), activators such as zinc oxide and fatty acids, waxes, mastication aids such as 2,2'-dibenzamidodiphenyldisulfide (DBD), and processing aids. The vulcanizable rubber blend preferably comprises these additional additives in a combined weight fraction in the range of 0.1 to 20 phr, preferably in the range of 0.5 to 15 phr, and particularly preferably in the range of 1 to 10 phr.

[0034] In addition, in addition to the organosilicon-modified resins described in further detail below, conventional resins can also be used. In this regard, examples that may be mentioned are vulcanizable rubber blends according to the invention, where the vulcanizable rubber blend comprises one or more additional resins that are not organosilicon-modified resins, and these additional resins are preferably plasticizer resins and / or reinforcing resins, preferably in a combined weight fraction in the range of 0.5 to 50 phr, particularly preferably in the range of 1 to 40 phr, and most particularly preferably in the range of 5 to 30 phr.

[0035] A person skilled in the art of rubber processing can easily distinguish resins from diene rubbers and any liquid polymer components, and in practice, this is achieved in particular by the average molar mass or the glass transition temperature. Examples that may be mentioned are vulcanizable rubber blends according to the invention, where the one or more additional resins have a glass transition temperature T determined by DSC of -20 °C or higher, preferably -15 °C or higher, and particularly preferably -10 °C or higher. g Examples that may also be mentioned additionally or alternatively are vulcanizable rubber blends according to the invention, where the one or more additional resins have a weight-average molar mass Mw determined by GPC in the range of 200 to 50,000 g / mol, preferably in the range of 400 to 40,000 g / mol, particularly preferably in the range of 600 to 30,000 g / mol, and most particularly preferably in the range of 800 to 20,000 g / mol.

[0036] With respect to the vulcanization behavior, preference is given to a vulcanizable rubber compound according to the invention, wherein the vulcanizable rubber compound contains 0.5 to 8.0 phr, preferably 0.8 to 6 phr and particularly preferably 1 to 4 phr of sulfur.

[0037] Additionally or alternatively, preference is also given to a vulcanizable rubber compound according to the invention, wherein the vulcanizable rubber compound contains further vulcanization components selected from the group consisting of crosslinking agents, vulcanization retarders and vulcanization accelerators (such as thiazole accelerators, mercapto accelerators, sulfenamide accelerators, thiocarbamate accelerators, thiuram accelerators, thiophosphate accelerators, thiourea accelerators, xanthate accelerators or guanidine accelerators). In addition to sulfur and sulfur donors, peroxide crosslinking agents can also be used, for example. Suitable peroxide crosslinking agents include, for example, organic peroxides such as dicumyl peroxide, bis(2,4-dichlorobenzoyl) peroxide, tert-butyl perbenzoate, 1,1-bis(tert-butylperoxy)-3,3,5-trimethylcyclohexane, butyl 4,4-bis(tert-butylperoxy)valerate, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexyne, di-tert-butyl peroxide, 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane, bis(2-tert-butylperoxyisopropyl)benzene or tert-butylcumyl peroxide, and the crosslinking agents can also be used in any combination with one another. Further alternatives that can be used are, for example, the crosslinking agents detailed in paragraph

[0094] of WO 2018 / 191187 A1.

[0038] A particularly important component of the vulcanizable rubber compound according to the invention is the organosilicon-modified resin, which is sometimes also referred to as the so-called organosilicon-modified resin. Examples of corresponding organosilicon-modified resins are disclosed, for example, in WO 2018 / 191187 A1.

[0039] These organosilicon-modified resins contain a typical oligomeric or (co)polymeric backbone of a conventional resin but additionally have at least one filler-reactive group. Since there is ultimately no clear boundary between oligomeric compounds and polymeric compounds and since it is not beneficial to make a distinction for the purposes of the present invention, the terms “(co)polymeric backbone” or “(co)polymer chain” are used in both cases in the context of the present invention, and thus the terms also include chains that could be referred to as (co)oligomer chains.

[0040] For fillers having free OH groups at the filler surface for use in rubber blends according to the invention, the filler reactive groups must be groups that can react with such surface free OH groups. According to the invention, these filler reactive groups can in principle be various functional groups that allow the required reactivity with OH groups, such as isocyanate groups for forming urethanes. The filler reactive groups can be, for example, those having a hydroxyl group and / or an ethoxy group and / or an epoxy group and / or a siloxane group and / or an amino group and / or an aminosiloxane and / or a carboxyl group and / or a phthalocyanine group and / or a silane-sulfide group. However, other modifications known to those skilled in the art, also called functionalizations, are also suitable. Metal atoms can be components of such functionalizations. However, according to the inventors, silicon-based linkages are particularly suitable for the curable rubber blends according to the invention. In this regard, those skilled in the art will further understand that the relevant reaction here is organosilanization (or organosilylation), and the specific organosilicon-modified resins of the invention are organosilicon-modified for this purpose, which means that these organosilicon-modified resins are ultimately organoalkoxysilyl organic compounds and can use the same functional groups known for this purpose in so-called silane coupling agents.

[0041] According to the inventors, with respect to the parts by weight of these organosilicon-modified resins, it is preferred for the curable rubber blends according to the invention, wherein the curable rubber blend comprises the one or more organosilicon-modified resins in combined parts by weight in the range of 0.5 to 60 phr, preferably in the range of 1 to 50 phr and particularly preferably in the range of 5 to 40 phr.

[0042] However, in this regard, the inventors have also particularly found in their own experiments that the combination of plasticizer oil and organosilicon-modified resins is particularly advantageous when the resin content is relatively low, because particularly advantageous resilience can be obtained, especially consistently, while a decrease in resilience may occur when the relevant components are combined with a high content of modified resins. Against this background, it is highly preferred for the curable rubber blends according to the invention, wherein the curable rubber blend comprises the one or more organosilicon-modified resins in combined parts by weight in the range of 0.1 to 20 phr, preferably in the range of 0.5 to 15 phr and particularly preferably in the range of 1 to 10 phr, and / or wherein the curable rubber blend comprises the one or more organosilicon-modified resins in combined parts by weight of 17 phr or less, preferably 13 phr or less, particularly preferably 10 phr or less and most particularly preferably 8 phr or less.

[0043] Additionally or alternatively, it is preferred that the curable rubber blend according to the invention comprises two or more different organosilicon-modified resins.

[0044] The inventors have successfully identified particularly suitable organosilicon-modified resins, by using which particularly advantageous rolling resistance and favorable wet grip behavior can be achieved, thus advantageously solving the relevant objective conflicts.

[0045] First, it is preferred that the curable rubber blend according to the invention, wherein the one or more organosilicon-modified resins have a glass transition temperature T measured by DSC of -20 °C or higher, preferably -15 °C or higher, and particularly preferably -10 °C or higher. g . Additionally or alternatively, it is also preferred that the curable rubber blend according to the invention, wherein the one or more organosilicon-modified resins have a weight-average molar mass Mw measured by GPC in the range of 200 to 60,000 g / mol, preferably in the range of 400 to 50,000 g / mol, particularly preferably in the range of 500 to 40,000 g / mol, and most particularly preferably in the range of 600 to 35,000 g / mol. The determination of the number-average molar mass is carried out by gel permeation chromatography according to DIN 55672-1:2016-03 (GPC using tetrahydrofuran as the eluent, polystyrene standards; size exclusion chromatography).

[0046] Even if the organosilicon-modified resin can be modified along the main chain, the inventors consider end modification to be particularly advantageous, provided that it is assumed that the resulting end bonding to the filler is sterically favorable. Therefore, it is preferred that the curable rubber blend according to the invention, wherein the one or more organosilicon-modified resins are end-organosilicon-modified resins.

[0047] According to the inventors, the chemical structure of the organosilicon modification can be generally defined first, i.e., the necessary silicon-containing functional groups are bonded to the (co)polymer chain of the resin via a linking group unit T. In this regard, it is preferred that the curable rubber blend according to the invention, wherein the one or more organosilicon-modified resins have at least one structural element of formula II):

[0048] II) (R 1 R 2 R 3 )Si-T-,

[0049] wherein R 1 , R 2 and R 3The groups are each independently a straight-chain or branched organic group having 1 to 20 non-hydrogen atoms, R 1 、R 2 and R 3 The organic group of at least one of the groups is bonded to the Si atom via an oxygen atom, where T is a straight-chain or branched, preferably straight-chain, organic linking unit having 1 to 60, preferably 2 to 40, and particularly preferably 5 to 20 non-hydrogen atoms, and the structural element having the formula II) is bonded via T to the (co)polymer chain of the organosilicon-modified resin.

[0050] Those skilled in the art will understand that the role of the (R 1 R 2 R 3 )Si group is to bond with the free OH groups at the filler surface; possible examples of these groups are disclosed in, for example, WO 2019 / 105614 A1. The (R 1 R 2 R 3 )Si group can be selected quite flexibly for the R 1 、R 2 and R 3 groups, provided that the organic group of at least one of the R 1 、R 2 and R 3 groups is bonded to the Si atom via an oxygen atom. Thus, a specific organosilicon-modified resin is an organoalkoxysilyl organic compound, which indicates to those skilled in the art that the organosilicon-modified resin is suitable for organosilanization. From the morpheme "organoalkoxysilyl", it can be seen that the corresponding organosilicon-modified resin has at least one organic group bonded to the central silicon atom of the (R 1 R 2 R 3 )Si group via an oxygen atom. This organoalkoxy group, such as an alkoxy group (e.g., ethoxy), is a leaving group that can be released during the condensation reaction at the surface of a filler having free OH groups at the surface, thereby forming, for example, Si-O-Si linkages in the case of a silicon-containing filler.

[0051] Even though it is fundamentally possible to use a case where the three R 1 、R 2 and R 3Silicone-modified resins in which two of the groups are directly bonded to the central silicon via carbon atoms and thus have only one leaving group, but in practice, silicone-modified resins having three (in most cases even identical) leaving groups are particularly preferred. These leaving groups are usually ethoxy groups that are released in the form of ethanol during the reaction. In most cases, the corresponding embodiments are preferred in terms of the synthesis and production costs of the compound and the treatment of the released leaving groups (which can be relatively easily removed from the compound). In addition, the corresponding silicone-modified resins having two or more leaving groups can also potentially bind to different filler particles at least

[0052] Although there is a high degree of flexibility in the design of the R 1 , R 2 and R 3 groups, in view of the above discussion, any orientation towards a particularly preferred (R 1 R 2 R 3 )Si group having three alkoxy groups (which in most cases have relatively short chains) is preferred. Thus, particularly preferred is a vulcanizable rubber compound according to the invention, wherein R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain alkoxy group or alkyl group having 1 to 10 carbon atoms, and at least one of the R 1 , R 2 and R 3 groups is an alkoxy group. Preferred is a vulcanizable rubber compound according to the invention, wherein R 1 , R 2 and R 3 groups are each independently a straight-chain alkoxy group or alkyl group. In this regard, additionally or alternatively, also preferred is a vulcanizable rubber compound according to the invention, wherein R 1 , R 2 and R 3 groups are each independently an alkoxy group or alkyl group having 1 to 5 carbon atoms, preferably having 2 or 3 carbon atoms. Additionally or alternatively, also preferred is a vulcanizable rubber compound according to the invention, wherein at least two, preferably all, of the R 1 , R 2 and R 3 groups are alkoxy groups. Fundamentally particularly preferred is a vulcanizable rubber compound according to the invention, wherein R 1 , R 2 and R 3 groups are the same. Most particularly preferred is a vulcanizable rubber compound according to the invention, wherein R 1 , R 2and R 3 The group is an ethoxy group.

[0053] In the above definitions, organic groups and organic linking units are defined. The term "organic" is clear to those skilled in the art and means that these units are or can be part of an organic molecule and in most cases means that these non-hydrogen atoms are selected from the group of non-metals. As understood by those skilled in the art, an organic group (e.g., -CH3) is attached via one attachment point to other components of a particular compound, and an organic linking unit (e.g., -CH2-CH2- or -CH2-CHR x -CH2-, where R x which in turn can be, for example, an organic group) is attached via two attachment points to other components of a particular compound.

[0054] The reference to "non-hydrogen atoms" in organic groups and linking units is convenient for those skilled in the art and is familiar to them based on their common knowledge. Thus, it can be stated that organic linking units / organic groups can not only be pure hydrocarbon units / hydrocarbon groups, but usually also contain heteroatoms, which means that organic linking units / organic groups also contain functional groups such as ester groups or ether groups. In this regard, those skilled in the art will automatically understand that, in addition to the "non-hydrogen atoms" defined above, hydrogen atoms may of course also be present and will in the vast majority of cases also be present. However, due to their monovalent character, hydrogen atoms do not exist in the chain but fill the remaining valences on the "non-hydrogen atoms". As understood by those skilled in the art, the expression "an organic group having three non-hydrogen atoms" correspondingly means, for example, that the organic group contains three additional non-hydrogen atoms in addition to hydrogen atoms.

[0055] In this regard, as understood by those skilled in the art, for substantially all embodiments, it is preferred that a vulcanizable rubber blend according to the invention is provided, wherein the non-hydrogen atoms are selected from the group consisting of C, N, O, S, P, F, Cl and Br and preferably selected from the group consisting of C, N, O and S. It is clear to those skilled in the art that the definition of organic linking units / organic groups results in an implicit functional limitation, that is, these groups / linking units are of course groups / linking units having a constitution that does not conflict with any fundamental chemical principles, which means that the above units are not composed only of halides, for example.

[0056] For the production of organosilicon-modified resins in a time- and cost-effective manner, the inventors have proposed the expedient of providing at least one heteroatom and preferably also further functional groups in the linking group unit T. As a result, not only is easier bonding of the organosilicon modification to the (co)polymer chains of the organosilicon-modified resin achieved. Moreover, the inventors have also found in experiments that the properties of the organosilicon-modified resin and its effect in the vulcanizable rubber blend may be influenced by the choice of the functional groups and heteroatoms. In this context, preferred is the vulcanizable rubber blend according to the invention, wherein the one or more organosilicon-modified resins have at least one structural element having the formula (III):

[0057] III) (R 1 R 2 R 3 )Si-U-A-V-,

[0058] wherein R 1 、R 2 and R 3 groups are each independently a straight-chain or branched organic group having 1 to 20 non-hydrogen atoms, and at least one of the organic groups of the R 1 、R 2 and R 3 groups is bonded to the Si atom via an oxygen atom, wherein U is a straight-chain or branched, preferably straight-chain, organic linking unit having 1 to 30, preferably 2 to 25, and particularly preferably 5 to 20 non-hydrogen atoms, and U preferably contains at least one functional group selected from the group consisting of amide groups, ester groups, carboxylic acid groups, ether groups and hydroxyl groups, particularly preferably selected from the group consisting of amide groups, ether groups and hydroxyl groups, wherein A is a heteroatom, preferably nitrogen or oxygen, particularly preferably oxygen, wherein V is a straight-chain or branched, preferably straight-chain, organic linking unit having 1 to 20, preferably 2 to 15, and particularly preferably 5 to 10 non-hydrogen atoms, and the structural element having the formula (III) is bonded to the (co)polymer chain of the organosilicon-modified resin via V, and V is preferably an aromatic organic chain, and V particularly preferably contains an aromatic ring having 6 carbon atoms.

[0059] Most particularly preferably, according to the experiments of the inventors, the bonding to the (co)polymer chain of the organosilicon-modified resin is achieved via an aromatic ring system. Specifically, preferred is the vulcanizable rubber blend according to the invention, wherein the one or more organosilicon-modified resins have at least one structural element having the formula (IV):

[0060] IV) (R 1 R 2 R 3 )Si-(CH2) i -W-A-Ar-,

[0061] wherein R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain organic group having 1 to 20 non-hydrogen atoms, and at least one of the organic groups of the R 1 , R 2 and R 3 groups is bonded to the Si atom via an oxygen atom, where i ranges from 1 to 20, preferably from 2 to 15, and particularly preferably from 3 to 10, where A is a heteroatom, preferably nitrogen or oxygen, particularly preferably oxygen, where Ar is an aromatic ring, preferably an aromatic ring having 6 carbon atoms, and the structural element having the formula (III) is bonded to the (co)polymer chain of the organosilicon-modified resin via Ar, where W is a straight-chain or branched-chain, preferably straight-chain, organic linking unit having 2 to 20, preferably 3 to 15, and particularly preferably 4 to 10 non-hydrogen atoms, and W contains at least one functional group selected from the group consisting of amide groups, ester groups, carboxylic acid groups, ether groups, and hydroxyl groups, preferably selected from the group consisting of amide groups, ether groups, and hydroxyl groups.

[0062] The inventors have successfully determined two structural elements for organosilicon modification in their own experiments, and these structural elements, in cooperation with specific plasticizer oils, have achieved particularly good results in solving the target conflict between rolling resistance and wet grip. Specifically, particularly preferred is a vulcanizable rubber compound according to the invention, wherein the one or more organosilicon-modified resins have at least one structural element having the formula (V):

[0063] V)

[0064] or at least one structural element having the formula (VI):

[0065] VI)

[0066] wherein R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain organic group having 1 to 20 non-hydrogen atoms, and at least one of the organic groups of the R 1 , R 2 and R 3 groups is bonded to the Si atom via an oxygen atom.

[0067] As explained above, the silicone-modified resin comprises (co)polymer chains as the main chain. They are (co)polymers which are produced or producible by polymerization from a specific monomer composition. It is convenient for the person skilled in the art and according to standard technical practice to define such (co)polymers by the production method and the starting materials used for production, since it is substantially impossible to define the corresponding materials in their entirety in any other way. According to standard technical practice, the provision of producibility is related to the monomer composition, which, according to the understanding of the person skilled in the art, comprises all monomeric components of the monomer units which are converted into (co)polymer chains during the polymerization. Thus, other components (such as solvents) which may be present in the reaction mixture during the polymerization but which are not incorporated into the (co)polymer chains during the polymerization are not part of the monomer composition.

[0068] Therefore, the starting point for further describing the (co)polymer chains is firstly a vulcanizable rubber compound according to the invention, in which the one or more silicone-modified resins comprise (co)polymer chains which are producible by polymerization of a monomer composition.

[0069] Starting therefrom, it is preferred that the vulcanizable rubber compound according to the invention is such that the monomer composition comprises one or more polymerizable monomers selected from the group consisting of unsaturated aliphatic monomers and unsaturated aromatic monomers, preferably selected from the group consisting of unsaturated aromatic monomers, and the monomer composition preferably consists of said monomers. Additionally or alternatively, it is preferred that the vulcanizable rubber compound according to the invention is such that the monomer composition comprises one or more polymerizable monomers selected from the group consisting of acrylates, methacrylates, terpenes, unsaturated fatty acids and vinyl aromatic compounds, and the monomer composition preferably consists of said monomers.

[0070] According to the inventors, it is particularly preferred that the vulcanizable rubber compound according to the invention is such that the monomer composition comprises one or more polymerizable monomers selected from the group consisting of ethylenically unsaturated aromatic monomers, preferably α-methylstyrene and / or styrene, and the monomer composition preferably consists of said monomers. Thus, it is also particularly preferred that the vulcanizable rubber compound according to the invention is such that the one or more silicone-modified resins comprise (co)polymer chains consisting of polymerized α-methylstyrene and / or styrene, preferably α-methylstyrene and styrene.

[0071] The second essential component of the vulcanizable rubber compound according to the invention is a plasticizer oil. According to the inventors, all typical plasticizer oils are in principle suitable for use in the vulcanizable rubber compound according to the invention. However, according to the inventors, it is preferred for the vulcanizable rubber compound according to the invention that the one or more plasticizer oils are selected from the group consisting of MES (mild extraction solvate), RAE (residual aromatic extract), TDAE (treated distillate aromatic extract), rubber-derived liquid oil (RTL), and biomass-derived liquid oil (BTL), preferably selected from the group consisting of MES, RAE, and TDAE (particularly preferably TDAE).

[0072] Examples that may be mentioned are vulcanizable rubber compounds according to the invention in which the one or more plasticizer oils are selected from the group consisting of mineral oil plasticizers (preferably aromatic, naphthenic, and paraffinic mineral oil plasticizers).

[0073] It is preferred for the vulcanizable rubber compound according to the invention that the one or more plasticizer oils are selected from the group consisting of plasticizer oils having a mass proportion of naphthenic compounds of 2.5% or more, preferably 5% or more, and particularly preferably 7.5% or more based on the mass of the plasticizer oil, preferably bio-based plasticizer oils, and / or in which the one or more plasticizer oils are selected from the group consisting of plasticizer oils having a mass proportion of paraffinic compounds of 2.5% or more, preferably 5% or more, and particularly preferably 7.5% or more based on the mass of the plasticizer oil, preferably bio-based plasticizer oils, and / or in which the one or more plasticizer oils are selected from the group consisting of plasticizer oils having a mass proportion of aromatic compounds of 0.1% or more, preferably 2.5% or more, and particularly preferably 5% or more based on the mass of the plasticizer oil, preferably bio-based plasticizer oils.

[0074] Regarding parts by mass, the inventors have been able to determine the range in which good results can be reliably achieved with respect to the target conflict between rolling resistance and wet grip. Specifically, it is preferred for the vulcanizable rubber compound according to the invention that the vulcanizable rubber compound contains the one or more plasticizer oils in a combined weight part range of 2 to 50 phr, particularly preferably in the range of 5 to 45 phr, and most particularly preferably in the range of 10 to 40 phr. According to the inventors, it is also particularly convenient to provide a specific minimum amount in order to achieve as significant an effect as possible. Thus, additionally or alternatively, it is preferred for the vulcanizable rubber compound according to the invention that the vulcanizable rubber compound contains the one or more plasticizer oils in a combined weight part range of 5 phr or more, preferably 10 phr or more, and particularly preferably 15 phr or more.

[0075] The inventors have recognized that particularly advantageous results can be achieved when the content of plasticizer oil is specifically adjusted with respect to the content of the silicone-modified resin. In this regard, according to the inventors, it is preferred that the curable rubber blend according to the invention, wherein the quotient of the combined parts by weight of plasticizer oil divided by the combined parts by weight of the silicone-modified resin is 5 or less, preferably 2.5 or less and particularly preferably 1.5 or less, and / or wherein the quotient of the combined parts by weight of plasticizer oil divided by the combined parts by weight of the silicone-modified resin is in the range of 0.8 to 5, preferably in the range of 1.0 to 4 and particularly preferably in the range of 1.2 to 3.

[0076] From the curable rubber blend according to the invention, vulcanized rubber and rubber products can be produced in a conventional manner. The corresponding method for producing vulcanized rubber or rubber products, in addition to producing the curable rubber blend according to the invention, further includes, for example, the following steps: vulcanizing the curable rubber blend according to the invention, preferably as part of a rubber blank and particularly preferably as part of an unvulcanized vehicle tire blank, to obtain vulcanized rubber, preferably as part of a rubber product and preferably as part of an inflated vehicle tire.

[0077] Here, the curable rubber blend according to the invention is vulcanized, for example, by conventional methods in the tire industry, such as sulfur-based crosslinking.

[0078] Therefore, the invention also relates to a vulcanized rubber that can be produced or is produced by vulcanizing the curable rubber blend according to the invention. In this regard, it is preferred that the vulcanized rubber according to the invention, wherein the vulcanized rubber can be produced by vulcanization at a temperature in the range of 120 °C to 200 °C, preferably in the range of 130 °C to 180 °C.

[0079] Therefore, the invention also relates to a rubber product comprising the vulcanized rubber according to the invention. Examples that may be mentioned are rubber products according to the invention, wherein the rubber product is selected from the group consisting of shoe soles, drive belts, hoses and belts. However, for substantially all cases, it is preferred that the rubber product according to the invention, wherein the rubber product is a vehicle tire, preferably an inflated vehicle tire.

[0080] Finally, the use of the curable rubber blend according to the invention and / or the vulcanized rubber according to the invention for improving rolling characteristics in the production of rubber products is also disclosed. Detailed Description

[0081] The invention and preferred embodiments of the invention will be explained and described in more detail below with reference to experiments.

[0082] A. Production of Curable Rubber Blend:

[0083] The vulcanizable rubber compound is produced in a laboratory mixer (300 mL, Brabender mixer, CW Brabender GmbH&Co., South Hackensack, New Jersey, USA) in three stages by conventional methods in the rubber industry under conventional conditions. The method includes first mixing all components except the vulcanization system (sulfur and substances affecting vulcanization) in the first mixing stage (basic mixing stage, rotor speed: 70 rpm, starting temperature: about 130 °C, final temperature: about 149 °C). The vulcanization system is added in the second stage (final mixing stage; rotor speed: 55 rpm, temperature: about 80 °C) to obtain the vulcanizable rubber compound.

[0084] The substances used in this regard are listed in Table 1.

[0085] Table 1 - Substances Used

[0086]

[0087]

[0088] Standardized vulcanized rubber as test specimens is produced from all vulcanizable rubber compounds by vulcanization (vulcanization conditions: t: 20 min, T: 160 °C).

[0089] B. Determination of the Physicochemical Properties of Vulcanized Rubber:

[0090] The following physicochemical properties are determined for the produced vulcanized rubber using the determination methods described below:

[0091] - Shore A hardness at room temperature (25 °C) according to DIN EN ISO 868:2003-10;

[0092] - Loss factor tanδ at 0 °C and 70 °C and the temperature at maximum loss factor (T@tanδmax) from temperature-dependent dynamic mechanical measurements (constant force, 10% compression ratio, ±0.2% strain amplitude, frequency 10 Hz) carried out by Eplexor according to DIN 53513:1990-03; and

[0093] - Wear at room temperature according to DIN ISO 4649:2021 (Method A using non-rotating test specimens).

[0094] The loss factor tanδ (0 °C) is used as an indicator of the wet grip of the tire. The greater the loss factor tanδ (0 °C), the better the wet grip characteristics. The loss factor tanδ (70 °C) is used as an indicator of the rolling resistance of the tire, and the smaller the loss factor tanδ (70 °C), the smaller the rolling resistance. The greater the difference Δtanδ (loss factor tanδ (0 °C) - loss factor tanδ (70 °C)), the more favorable the vulcanized rubber under discussion is in terms of the target conflict between wet grip characteristics and rolling resistance.

[0095] C. Series 1 tests:

[0096] In the Series 1 tests, ten vulcanizable rubber compounds were produced, and their compositions are detailed in Table 2.

[0097] Table 2 - Vulcanizable rubber compounds according to Series 1 tests (all data in phr)

[0098]

[0099]

[0100] The material properties determined for the relevant vulcanized rubber are summarized in Table 3.

[0101] Table 3 - Material properties of Series 1 tests

[0102]

[0103] D. Series 2 tests:

[0104] In the Series 2 tests, four vulcanizable rubber compounds were produced, and their compositions are detailed in Table 4.

[0105] Table 4 - Vulcanizable rubber compounds according to Series 2 tests (all data in phr)

[0106]

[0107]

[0108] The material properties determined for the relevant vulcanized rubber are summarized in Table 5.

[0109] Table 5 - Material properties of Series 2 tests

[0110]

[0111] E. Series 3 tests:

[0112] In the Series 3 tests, eight vulcanizable rubber compounds were produced, and their compositions are detailed in Table 6.

[0113] Table 6 - Vulcanizable rubber blends according to the 3rd series of tests (all data in phr)

[0114]

[0115]

[0116] The material properties determined for the relevant vulcanized rubbers are summarized in Table 7.

[0117] Table 7 - Material properties of the 3rd series of tests

[0118]

[0119]

[0120] F evaluation:

[0121] The results of the 1st, 2nd and 3rd series of tests show that vulcanized rubbers can be obtained from the vulcanizable rubber blends according to the invention, which advantageously solve the target conflict between rolling resistance and wet grip.

[0122] For all vulcanizable rubber blends according to the invention, the Δtanδ values of the vulcanized rubbers obtained by using a plasticizer oil in combination with a silicone-modified resin (as an indicator of the target conflict between rolling resistance and wet grip) are consistently improved compared to those of the corresponding comparative systems without plasticizer oil.

[0123] The 3rd series of tests clearly shows that the use of the plasticizer oil according to the invention is advantageous for solving the target conflict between wet grip and rolling resistance compared to other plasticizers such as liquid polybutadiene.

Claims

1. A vulcanizable rubber compound, comprising: a) one or more diene rubbers, b) one or more fillers selected from the group consisting of fillers having free OH groups at the filler surface, c) one or more silicone-modified resins, and d) one or more plasticizer oils in a combined weight fraction ranging from 1 to 60 phr.

2. The vulcanizable rubber blend according to claim 1, wherein, The vulcanizable rubber compound comprises the one or more fillers in a combined weight fraction ranging from 5 to 250 phr.

3. The vulcanizable rubber blend according to any one of claims 1 and 2, wherein, The one or more fillers are selected from the group consisting of amorphous silica.

4. The vulcanizable rubber compound according to any one of claims 1 to 3, wherein, The vulcanizable rubber compound comprises the one or more silicone-modified resins in a combined weight fraction ranging from 0.5 to 60 phr.

5. The vulcanizable rubber compound according to any one of claims 1 to 4, wherein The one or more silicone-modified resins have at least one structural element having formula II): II)(R 1 R 2 R 3 )Si-T-, wherein the R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain organic group having 1 to 20 non-hydrogen atoms, and the organic group of at least one of the R 1 , R 2 and R 3 groups is bonded to the Si atom via an oxygen atom, wherein T is a straight-chain or branched-chain organic linking unit having 1 to 60 non-hydrogen atoms, and the structural element having formula (II) is bonded to the (co)polymer chain of the organosilicon-modified resin via the T.

6. The vulcanizable rubber blend according to any one of claims 1 to 5, wherein, The one or more silicone-modified resins have at least one structural element having formula III): III)(R 1 R 2 R 3 )Si-U-A-V-, wherein the R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain organic group having 1 to 20 non-hydrogen atoms, and the organic group of at least one of the R 1 , R 2 and R 3 groups is bonded to the Si atom via an oxygen atom, wherein U is a straight-chain or branched organic linking unit having 1 to 30 non-hydrogen atoms, wherein A is a heteroatom, wherein V is a straight-chain or branched organic linking unit having 1 to 20 non-hydrogen atoms, and the structural element having formula III) is bonded via the V to the (co)polymer chain of the silicone-modified resin.

7. The vulcanizable rubber blend according to any one of claims 1 to 6, wherein, The one or more silicone-modified resins have at least one structural element having formula IV): IV)(R 1 R 2 R 3 )Si-(CH2) i -W-A-Ar-, wherein the R 1 , R 2 and R 3 groups are each independently a straight-chain or branched-chain organic group having 1 to 20 non-hydrogen atoms, and the organic group of at least one of the R 1 , R 2 and R 3 groups is bonded to the Si atom via an oxygen atom, wherein i is in the range of 1 to 20, wherein A is a heteroatom, wherein Ar is an aromatic ring, and the structural element having formula (III) is bonded to the (co)polymer chain of the organosilicon-modified resin via the Ar, and wherein W is a straight-chain or branched-chain organic linking unit having 2 to 20 non-hydrogen atoms, and W contains at least one functional group selected from the group consisting of an amide group, an ester group, a carboxylic acid group, an ether group, and a hydroxyl group.

8. The vulcanizable rubber blend according to any one of claims 1 to 7, wherein, The one or more plasticizer oils are selected from the group consisting of plasticizer oils having a mass fraction of naphthenic compounds of 2.5% or more based on the mass of the plasticizer oil.

9. The vulcanizable rubber compound according to any one of claims 1 to 8, wherein The vulcanizable rubber compound comprises the one or more plasticizer oils in a combined weight fraction ranging from 2 to 50 phr.

10. The vulcanizable rubber blend according to any one of claims 1 to 9, wherein, The quotient of the combined weight fraction of these plasticizer oils divided by the combined weight fraction of these silicone-modified resins is in the range of 0.8 to 5.

11. A vulcanized rubber, which can be produced or is produced by vulcanizing the vulcanizable rubber compound according to any one of claims 1 to 10.

12. A rubber product, comprising the vulcanized rubber according to claim 11.

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