Organosilyl polysulfides and rubber mixtures containing the same

Abstract

The present invention relates to novel organosilyl polysulfides of the formula (I), wherein the substituents R 1 up to R 8 and the index x have the definitions specified in the description. The organosilyl polysulfides are excellently suitable for the production of rubber mixtures with improved mixing properties. The invention also relates to the vulcanizates obtainable from the novel organosilyl polysulfides and to rubber products which are characterized by increased hardness, strength and elongation at break and low rolling resistance of the tires produced therefrom.

Description

Technical Field

[0001] This invention relates to novel organosilicon polysulfides and their use as reinforcing additives for rubber, rubber blends containing these organosilicon polysulfides, the use of these organosilicon polysulfides in the production of these rubber blends, and cured products and molded articles, particularly tires, that can be obtained from these rubber blends. Background Technology

[0002] Sulfur-containing organosilicon compounds are known to be suitable as reinforcing additives in rubber blends. Therefore, DE-A2141159, DE-A 2141160, and DE-A 2255577 describe sulfur-containing organosilicones as reinforcing additives, particularly for silica-containing cured rubber products used in tire applications. The sulfur-containing organosilicones disclosed therein are derived from bis(trialkoxysilylalkyl) polysulfides, such as bis(triethoxysilylpropyl) tetrasulfide (TESPT), which is explicitly described for example.

[0003] DE-A 2035778 also discloses organosilane-based reinforcing additives derived from trialkoxysilylpropyl compounds. A drawback of these compounds known from the prior art is that hysteresis loss decreases not only at high temperatures (approximately 60°C, related to rolling resistance) but also at low temperatures (0°C). Reduction in hysteresis loss is desirable in principle because it leads to a reduction in the rolling resistance of motor vehicle tires and thus a reduction in vehicle fuel consumption. However, low hysteresis at low temperatures (0°C to 20°C) is known to be associated with poor wet traction in motor vehicle tires. Therefore, it is difficult to reconcile these two requirements: low rolling resistance and good wet traction.

[0004] EP-A 447066 also describes the use of sulfur-containing organosilanes as adhesion enhancers in rubber compounds used to produce highly silica-filled tire treads. The combination of specific silane-modified rubber, silica fillers, and adhesion enhancers based on specific trialkoxyalkyl polysulfides enables a reduction in tire rolling resistance. However, it is also evident in these tire compounds that the aforementioned adhesion enhancers not only reduce rolling resistance but also reduce wet grip.

[0005] EP-A 0680997 also discloses the use of certain bis-alkoxy / alkyl-substituted silylmethylene polysulfides as reinforcing additives in rubber blends with good rolling resistance and good wet grip. The disadvantages here include the expensive and inconvenient production of the raw materials used to manufacture the reinforcing additives via photochlorination, and a significant deterioration in the rubber's performance characteristics such as strength, elongation at break, and hardness.

[0006] EP-A 3622015 describes the use of bis(dimethylethoxysilylisobutylene) polysulfides as reinforcing additives in rubber compounds with good rolling resistance and good wet grip properties. However, the use of these compounds in tire production results in the release of 2 mol of ethanol per mol, which may be disadvantageous in practice. Summary of the Invention

[0007] Therefore, the object of the present invention is to provide novel reinforcing additives for rubber based on sulfur-containing organosilicon compounds, as well as novel rubber mixtures, which overcome the aforementioned disadvantages of the prior art.

[0008] It has been surprisingly found that certain organosilanes polysulfides, each having a propylene group or each having a propylene group branched at the 2-position as a spacer group between silicon and sulfur atoms, are very well suited as reinforcing additives for rubber compounds without causing the rubber compounds to harden, resulting in the emission of volatile organic compounds (VOCs).

[0009] Novel organosilyl polysulfides result in a rapid and complete curing time (T95) for rubber compounds and produce advantageous temperature-dependent hysteresis characteristics and positive performance features such as high strength and high elongation at break in the cured products available from them. Tires produced from these cured products are characterized, in particular, by low rolling resistance and good wet grip. Furthermore, the novel organosilyl polysulfides are characterized by a very advantageous low mixing viscosity, thus allowing for simpler compound production.

[0010] Therefore, the present invention provides novel organosilanesyl polysulfides of formula (I).

[0011]

[0012] in

[0013] R 1 R 3 R 6 and R 8 Same or different and indicating C1-C4-alkyl,

[0014] R 4 and R 5 The same or different and indicating hydrogen or C1-C4-alkyl,

[0015] R 2 and R 7 The following formula represents a group

[0016]

[0017] in

[0018] a, b, and c are each independently 0, 1, 2, or 3, preferably 1 or 2, and particularly preferably 1.

[0019] The condition is that the sum of a+b+c has a value of 3 to 6, preferably 3 or 4, and particularly preferably 3.

[0020] and

[0021] x is an integer from 2 to 8.

[0022] The preferred formula (I) is an organosilicon polysulfide.

[0023] in

[0024] R1, R3, R 6 and R 8 The same or different and indicating methyl or ethyl,

[0025] R 4 and R 5 The same or different and indicating hydrogen, methyl or ethyl,

[0026] R 2 and R 7 The group representing formula (A),

[0027] in

[0028] a is 1 or 2.

[0029] b is 1 or 2.

[0030] c is 1 or 2

[0031] The condition is that the sum of a+b+c has a value of 3 to 6, preferably 3 or 4, and particularly preferably 3.

[0032] and

[0033] x is an integer from 2 to 8.

[0034] The organosilanes polysulfides of particularly preferred form (I), wherein,

[0035] R 1 R 3 R 6 and R 8 Indicates methyl,

[0036] R 4 and R 5 Same or different and indicating hydrogen or methyl,

[0037] R 2 and R 7 The group representing formula (A),

[0038] in

[0039] a is 1 or 2.

[0040] b is 1 or 2.

[0041] c is 1 or 2

[0042] The condition is that the sum of a+b+c is 3 or 4.

[0043] and

[0044] x is an integer from 2 to 8.

[0045] The organosilanes polysulfides of the very preferred form (I), wherein,

[0046] R 1 R 3 R 6 and R 8 Indicates methyl,

[0047] R 4 and R 5 The same and indicating hydrogen or methyl,

[0048] R 2 and R 7 The group representing formula (A),

[0049] in

[0050] a, b, and c are all 1

[0051] and

[0052] x is an integer from 2 to 8.

[0053] Especially preferred are organosilanes of formulas (Ia) and (Ib).

[0054]

[0055] in

[0056] x is an integer from 2 to 8.

[0057] Its chemical name is bis[di(ethyleneoxyhydroxymethyl)ethyleneoxy-butoxydimethylsilylpropyl] polysulfide

[0058] as well as

[0059]

[0060] in

[0061] x is an integer from 2 to 8.

[0062] Its chemical name is bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl] polysulfide.

[0063] Those skilled in the art know that organosilicon polysulfides can undergo disproportionation under the influence of temperature and / or solvent. Therefore, the organosilicon polysulfides according to the invention are mostly in the form of mixtures, wherein the number of sulfur atoms in the organosilicon polysulfides is in the number average range of typically 3.6 to 4.4, preferably 3.8 to 4.2, and particularly 4.0.

[0064] The present invention further provides a mixture containing at least two organosilicon polysulfides of formula (I), wherein the substituent R 1 To R 8 And x has the above general and preferred definitions and is different from x at least in the value of x, wherein the number of sulfur atoms x is number average The value is 3.6 to 4.4, preferably 3.8 to 4.2, and especially 4.0.

[0065] A mixture of organosilanes containing at least two formulas (Ia) and / or (Ib) is particularly preferred, which differ in value x, wherein the number average of x is [missing information]. The value is 3.6 to 4.4, preferably 3.8 to 4.2, and especially 4.0.

[0066] According to the invention, the organosilicon polysulfide of formula (I) can be produced by reacting at least two haloalkylsilyl ethers of formula (II) in the presence of at least one alcohol solvent.

[0067]

[0068] in

[0069] R 9 Represents group R 4 Or R 5 ,

[0070] R 10 Represents group R 3 Or R 6 ,

[0071] R 11 Represents group R 2 Or R 7 and

[0072] R 12 Represents group R 1 Or R 8 ,

[0073] Wherein group R 1 To R8 Having the general and preferred definitions specified for equation (I)

[0074] and

[0075] Hal represents halogen, preferably chlorine.

[0076] With at least one metal polysulfide of formula (III)

[0077] S x M2 (III)

[0078] in

[0079] x has the general and preferred definitions specified by equation (I).

[0080] and

[0081] M represents a metal ion from the group consisting of lithium, sodium, and potassium, with sodium being preferred.

[0082] Methods for producing organosilicon polysulfides are known in principle. Organosilicon polysulfides of formula (I) according to the invention can be produced by methods similar to those known (such as those described, for example, in DE-A 2 141 159).

[0083] The production of the organosilicon polysulfides according to the invention generally involves using 0.5 mol of a metal polysulfide of formula (III) based on a total amount of one mole of a haloalkylsilyl ether of formula (II), with sodium polysulfide being particularly preferred.

[0084] The method for producing organosilicon polysulfides according to the present invention can be carried out over a wide temperature range. It is preferably carried out at temperatures ranging from -20°C to +90°C.

[0085] The method for producing organosilicon polysulfides according to the present invention is preferably carried out in the presence of at least one alcohol derived from the group consisting of methanol, ethanol, n-propanol, isopropanol, isobutanol, pentanol, hexanol, n-octanol, isooctanol, ethylene glycol, 1,2- and 1,3-propanediol, 1,4-butanediol and / or 1,6-hexanediol.

[0086] The method for producing organosilicon polysulfides according to the invention can be carried out over a wide pressure range. It is typically carried out at pressures from 0.9 to 1.1 bar, preferably at standard pressures.

[0087] The production of the organosilanesyl polysulfide (I) according to the present invention is generally carried out by first loading a metal polysulfide of formula (III) into anhydrous alcohol, preferably anhydrous methanol, heating the mixture to its boiling point under inert conditions, and then adding at least two haloalkylsilyl ethers of formula (II). After the reaction is complete, the precipitated alkali metal salt is filtered off as a byproduct, and the compound of formula (I) is separated by distillation to remove the solvent and as the remaining bottom product in pure form, with a yield >85%.

[0088] The haloalkylsilyl ethers of formula (II) are novel and also constitute part of the subject matter of this invention.

[0089] Methods for producing haloalkylsilyl ethers are known in principle.

[0090] According to the invention, haloalkylsilyl ethers of formula (II) can be produced in a known manner, for example similar to the method described in EP-A0669338, by reacting at least one ruthenium catalyst with at least one haloallyl compound of formula (IV).

[0091]

[0092] Where R 9 Having the general and preferred definitions specified for equation (II)

[0093] and

[0094] Hal represents halogen, preferably chlorine.

[0095] With at least one silane of formula (V)

[0096]

[0097] Where R 10 R 11 and R 12 It has the general and preferred definitions specified for equation (II).

[0098] The production of haloalkylsilyl ethers of formula (II) according to the present invention is preferably carried out without the addition of solvents.

[0099] Typically, 1.15 to 2 mol, preferably 1.6 to 2.0 mol, of silane of formula (V) is used per mol of allyl halopropionate of formula (IV).

[0100] Suitable ruthenium catalysts preferably include compounds disclosed in EP-A 0669338. Ruthenium catalyst Ru3(CO) 12 It is particularly suitable for the production of haloalkylsilyl ethers according to formula (II) of the present invention.

[0101] Typically, at least one ruthenium catalyst is used per mol of the haloallylic compound of formula (IV) at a concentration of 10 to 200 ppm, preferably 15 to 100 ppm.

[0102] The reaction of the haloallyl compound of formula (IV) with the silane of formula (V) is usually carried out at a temperature ranging from 20°C to 150°C, preferably from 70°C to 90°C.

[0103] The reaction typically takes place over a period of 1 to 100 hours, preferably over a period of 1.5 to 5 hours.

[0104] The progress of the reaction can be monitored by TLC (thin-layer chromatography). Once the reaction is complete, the haloalkylsilyl ether of formula (II) can be purified by distillation. This allows for yields up to 97%.

[0105] Halogenated allyl compounds of formula (IV) are known and are available, for example, as commercial products from Aldrich (CAS No. 107-05-1 or CAS No. 563-47-3).

[0106] Silanes of formula (V) can be produced in a manner known per se (see, for example, US2011 / 0105780) by causing the following reaction: halosilanes of formula (VI)

[0107]

[0108] in

[0109] R 1 and R 3 Having the general and preferred definitions specified for equation (I)

[0110] and

[0111] Hal represents halogen, preferably chlorine.

[0112] With equation R 11 OH alcohols, where R 11 It has the general and preferred definitions specified for equation (I).

[0113] The silane of formula (VI) is known and is available as a commercial product, for example, from Sigma-Aldrich.

[0114] The present invention further provides a rubber mixture comprising at least one rubber and at least one compound of formula (I).

[0115]

[0116] Wherein the substituent R1 To R 8 The exponent x has the general and preferred definitions specified above.

[0117] Typically, the total content of the compound of formula (I) in the rubber mixture according to the invention is 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 2 to 13 parts by weight and very particularly preferably 3 to 11 parts by weight, based on a total of 100 parts by weight of rubber in each case.

[0118] The compound of formula (I) can be added to the rubber mixture in its pure form, or separately adsorbed onto an inert organic or inorganic carrier. Suitable carrier materials include silica, natural or synthetic silicates, alumina, and carbon black.

[0119] The rubber compound according to the invention contains at least one type of rubber.

[0120] It is preferred when the rubber mixture according to the invention contains at least one natural rubber (NR) and / or synthetic rubber.

[0121] Suitable synthetic rubbers include, for example

[0122] BR-polybutadiene

[0123] ABR-butadiene / C1-C4 alkyl acrylate copolymer

[0124] CR-polychloroprene

[0125] IR-polyisoprene

[0126] SBR-styrene / butadiene copolymer having a styrene content of 1%-60%, preferably 20%-50%, by weight.

[0127] IIR-isobutylene / isoprene copolymer

[0128] NBR-butadiene / acrylonitrile copolymer, having an acrylonitrile content of 5% to 60% by weight, preferably 10% to 50% by weight.

[0129] HNBR - Partially or fully hydrogenated NBR rubber

[0130] EPDM-ethylene / propylene / diene copolymer

[0131] And mixtures of two or more of these rubbers.

[0132] It is preferred when the rubber compound according to the invention contains at least one SBR rubber, preferably a functionalized SBR rubber, and optionally one or more BR rubbers.

[0133] According to the present invention, the functionalized SBR rubber is an SBR rubber in which one or more functional groups, particularly carboxyl groups and / or thiol-containing groups, are substituted at the main chain and / or end groups.

[0134] The rubber mixture according to the invention is particularly preferably a mixture of SBR and BR rubber in a weight ratio of SBR:BR of 100:0 to 60:40.

[0135] In another advantageous embodiment, the rubber compound according to the invention contains at least one type of natural rubber.

[0136] The rubber compound according to the invention preferably contains one or more fillers. Suitable fillers generally include all fillers known in the art for this purpose.

[0137] Suitable active fillers include hydroxyl-containing oxidizing compounds, such as certain types of silica, as well as carbon black.

[0138] The rubber compound according to the invention typically contains 10 to 190 parts by weight, preferably 30 to 150 parts by weight, and particularly preferably 50 to 130 parts by weight, of at least one filler, in each case based on a total rubber amount of 100 parts by weight.

[0139] The rubber compound according to the invention preferably contains at least one oxidizing filler containing hydroxyl groups.

[0140] Typically, the content of hydroxyl-containing oxidized filler in the rubber compound according to the invention is at least 10 parts by weight, preferably 20 to 150 parts by weight, particularly preferably 50 to 140 parts by weight, and very particularly preferably 80 to 130 parts by weight, based on a total filler content of 100 parts by weight in each case.

[0141] Suitable hydroxyl-containing oxide fillers are preferably from the group consisting of those that are suitable for use with respect to hydroxyl groups.

[0142] - With 5 to 1000, preferably 20 to 400m 2 Silica with a specific surface area (BET) of / g and a primary particle size of 100 to 400 nm, wherein the silica optionally also exists as a mixed oxide with other metal oxides (such as oxides of Al, Mg, Ca, Ba, Zn, Zr, Ti).

[0143] as well as

[0144] - Synthetic silicates, such as aluminum silicate and alkaline earth metal silicates (such as magnesium silicate or calcium silicate), have a molecular weight of 20 to 400 m. 2 Specific surface area (BET) per g and primary particle size ranging from 10 to 400 nm.

[0145] The hydroxyl-containing oxidized fillers present in the rubber mixtures of the present invention and derived from the group consisting of silica are preferably those that can be produced, for example, by precipitation of silicate solutions or by flame hydrolysis of silicon halides.

[0146] It is preferred when the rubber compound according to the invention contains at least one hydroxyl-containing oxidizing filler selected from the group having a specific surface area (BET) in the range of 20 to 400 m² / g based on 5 to 150 parts by weight, preferably 50 to 140 parts by weight, and particularly preferably 80 to 130 parts by weight of total rubber in each case.

[0147] The rubber compound according to the invention may further contain at least one carbon black as a filler.

[0148] According to the present invention, it is preferably obtained by lamp blackening, furnace blackening or gas blackening methods and has a range of 20 to 200 μm. 2 Carbon black with a specific surface area (BET) in the range of / g, such as SAF, ISAF, IISAF, HAF, FEF, or GPF carbon black.

[0149] The rubber compound according to the invention typically contains at least one component in an amount of 0 to 40 parts by weight, preferably 0 to 30 parts by weight, and particularly preferably 0 to 20 parts by weight, based on a total rubber amount of 100 parts by weight, in each case having a concentration of 20 to 200 mg / L. 2 Carbon black with a specific surface area (BET) in the range of / g.

[0150] All BET values ​​are related to the specific surface area measured according to DIN 66131. ​​The reported primary particle size refers to the value determined by scanning electron microscopy.

[0151] In a preferred alternative embodiment, the rubber compound according to the invention contains at least one of the above-mentioned carbon black and at least one of the above-mentioned silica as fillers.

[0152] In a particularly preferred alternative embodiment, the rubber compound according to the invention contains 20 to 120 parts by weight, preferably 30 to 100 parts by weight, and particularly preferably 40 to 90 parts by weight of at least one hydroxyl-containing oxidized filler from the group consisting of silica having a specific surface area (BET) in the range of 20 to 400 m² / g, and 20 to 90 parts by weight, preferably 30 to 80 parts by weight, and particularly preferably 40 to 70 parts by weight of at least one having a specific surface area (BET) in the range of 20 to 200 m² / g. 2 Carbon black with a specific surface area (BET) in the range of / g, based on 100 parts by weight of total rubber in each case.

[0153] The rubber mixture of the present invention may contain one or more crosslinking agents.

[0154] Preferred crosslinking agents according to the invention are, in particular, sulfur and sulfur donors, as well as metal oxides such as magnesium oxide and / or zinc oxide.

[0155] Sulfur can be used in soluble or insoluble form or as a sulfur donor. Suitable sulfur donors include, for example, dithiodimorpholine (DTDM), 2-morpholinodithiobenzothiazole (MBSS), caprolactam disulfide, bis(pentamethylene)thiuram tetrasulfide (DPTT), and tetramethylthiuram disulfide (TMTD).

[0156] It is particularly preferred when the rubber compound according to the invention contains at least one sulfur donor and / or sulfur, especially sulfur.

[0157] The rubber mixtures according to the invention typically contain 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, of at least one of the listed crosslinking agents, in each case based on a total of 100 parts by weight of rubber.

[0158] The rubber mixture according to the present invention may contain one or more curing accelerators.

[0159] Preferred curing accelerators according to the present invention are mercaptobenzothiazole, mercaptosulfonamide, thiocarbamate, thiocarbonate and dithiophosphate, as well as sulfur donors such as dithiodicaprolactam, dithiodimorpholine and xanthate.

[0160] The rubber mixtures according to the invention typically contain 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, of at least one of the listed curing accelerators, in each case based on a total of 100 parts by weight of rubber.

[0161] In addition to the compounds of formula (I), the rubber mixtures according to the invention may also contain one or more additional reinforcing additives commonly used for these purposes and known from the prior art.

[0162] In addition to the additives described above, the rubber mixtures according to the invention may also contain other rubber additives familiar to those skilled in the art, such as reaction accelerators, aging stabilizers, heat stabilizers, light stabilizers, anti-ozone agents, processing aids, plasticizers, tackifiers, foaming agents, dyes, pigments, waxes, fillers, organic acids, reaction retarders, metal oxides, activators such as triethanolamine, polyethylene glycol, hexanediol, and fillers from the group of natural silicates, such as kaolin and other naturally occurring silicates, as well as glass fibers and glass fiber products, for example in the form of pads, strands or microspheres.

[0163] The rubber mixtures according to the invention contain a list of rubber additives in typical amounts for these additives, typically in amounts from 0.1 to 30 parts by weight in each case, based on a total rubber amount of 100 parts by weight in each case.

[0164] The rubber compound according to the present invention may contain one or more auxiliary accelerators.

[0165] In silica-based rubber blends, such as those used in tire production, diphenylguanidine (DPG) or structurally similar aromatic guanidines are typically used as co-accelerators to controllably regulate the crosslinking rate and blend viscosity during mixing. However, a very important adverse characteristic associated with the use of DPG is its release of aniline during curing, which is suspected to be carcinogenic. It has now been found, unexpectedly, that in the rubber blends of the present invention, DPG can be advantageously replaced by 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (trade name: It is also possible to replace DPG with an auxiliary accelerator such as TBzTD (tetrabenzylthiuram disulfide) or dithiophosphate.

[0166] Therefore, the present invention also includes rubber compounds that are substantially DPG-free.

[0167] The silica-based rubber compound according to the present invention preferably contains at least one auxiliary accelerator derived from 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (trade name: The group consists of tetrabenzylthiuram disulfide (TBzTD) and dithiophosphates.

[0168] The rubber mixtures according to the invention typically contain 0.1 to 1.0 parts by weight, preferably 0.2 to 0.5 parts by weight, of at least one of the listed auxiliary accelerators, in each case based on a total of 100 parts by weight of rubber.

[0169] Therefore, the present invention also provides rubber blends of the present invention that are substantially free of diphenylguanidine and / or substituted diphenylguanidine, especially those having a content of up to 0.4 parts by weight, preferably 0.1 to 0.2 parts by weight, particularly preferably 0.05 to 0.1 parts by weight and very particularly preferably 0.001 to 0.04 parts by weight of diphenylguanidine and / or substituted diphenylguanidine, in each case based on a total rubber amount of 100 parts by weight.

[0170] The rubber mixture according to the invention preferably contains at least one rubber, 5 to 150 parts by weight, preferably 50 to 140 parts by weight and particularly preferably 80 to 130 parts by weight of at least one silica, 0 to 40 parts by weight, preferably 0 to 30 parts by weight and particularly preferably 0 to 20 parts by weight of carbon black, and 0.1 to 15, preferably 1 to 12, particularly preferably 2 to 10 parts by weight and especially 3 to 8 parts by weight of at least one compound of formula (I), in each case based on a total of 100 parts by weight of rubber.

[0171] Also preferably, the rubber mixture according to the invention contains at least one rubber, 5 to 150 parts by weight, preferably 50 to 140 parts by weight, and particularly preferably 80 to 130 parts by weight of at least one silica, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, and particularly preferably 0 to 20 parts by weight of carbon black, and 0.1 to 15, preferably 1 to 14, particularly preferably 2 to 13 parts by weight, and especially 3 to 11 parts by weight of at least one compound of formula (I), and 0.1 to 1.0 parts by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane. In each case, the total amount of rubber is based on 100 parts by weight.

[0172] Very particularly preferred are the rubber mixtures according to the invention containing at least one rubber, particularly at least one SBR rubber, preferably functionalized SBR rubber and optionally one or more BR rubbers, 5 to 150 parts by weight, preferably 50 to 140 parts by weight and particularly preferably 80 to 130 parts by weight of at least one silica, particularly having a specific surface area (BET) of 5 to 1000 m² / g, preferably 20 to 400 m² / g, and having a primary particle size of 100 to 400 nm, and 0 to 40 parts by weight, preferably 0 to 30 parts by weight and particularly preferably 0 to 20 parts by weight of carbon black, particularly... Specifically, it has a specific surface area (BET) in the range of 20 to 200 m² / g, and at least one compound of formula (I), particularly a compound of formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]tetrasulfide) and / or a compound of formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]tetrasulfide), based on 100 parts by weight of the total amount of rubber in each case.

[0173] It is also highly preferred that the rubber mixture according to the invention contains at least one rubber, particularly at least one SBR rubber, preferably a functionalized SBR rubber and optionally one or more BR rubbers, 5 to 150 parts by weight, preferably 50 to 140 parts by weight and particularly preferably 80 to 130 parts by weight of at least one silica, particularly having a specific surface area (BET) of 5 to 1000 m² / g, preferably 20 to 400 m² / g, and having a primary particle size of 100 to 400 nm, and 0 to 40 parts by weight, preferably 0 to 30 parts by weight and particularly preferably 0 to 20 parts by weight of carbon black, particularly having a particle size of 20 A specific surface area (BET) in the range of up to 200 m² / g, and 0.1 to 15, preferably 1 to 14, particularly preferably 2 to 13 parts by weight and especially 3 to 11 parts by weight of at least one compound of formula (I), particularly a compound of formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or a compound of formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide) and 0.1 to 0.5 parts by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane. The content of diphenylguanidine and / or substituted diphenylguanidine is up to 0.4 parts by weight, preferably 0.1 to 0.2 parts by weight, particularly preferably 0.05 to 0.1 parts by weight and very particularly preferably 0.001 to 0.04 parts by weight, based on 100 parts by weight of total rubber in each case.

[0174] Also very particularly preferred is the rubber compound according to the invention containing at least one natural rubber, 5 to 150 parts by weight, preferably 50 to 140 parts by weight, and particularly preferably 80 to 130 parts by weight of at least one silica, particularly having a specific surface area (BET) of 5 to 1000 m² / g, preferably 20 to 400 m² / g, and having a primary particle size of 100 to 400 nm, and 0 to 40 parts by weight, preferably 0 to 30 parts by weight, and particularly preferably 0 to 20 parts by weight of carbon black, particularly having a primary particle size in the range of 20 to 200 m² / g. The specific surface area (BET) within the range, and 0.1 to 15, preferably 1 to 14, particularly preferably 2 to 13 parts by weight and especially 3 to 11 parts by weight of at least one compound of formula (I), particularly a compound of formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or a compound of formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide), in each case based on 100 parts by weight of the total amount of rubber.

[0175] It is also highly preferred that the rubber compound according to the invention contains at least one natural rubber, 5 to 150 parts by weight, preferably 50 to 140 parts by weight, and particularly preferably 80 to 130 parts by weight of at least one silica, particularly having a specific surface area (BET) of 5 to 1000 m² / g, preferably 20 to 400 m² / g, and having a primary particle size of 100 to 400 nm, and 0 to 40 parts by weight, preferably 0 to 30 parts by weight, and particularly preferably 0 to 20 parts by weight of carbon black, particularly having a specific surface area (BET) in the range of 20 to 200 m² / g. ET), and 0.1 to 15, preferably 1 to 14, particularly preferably 2 to 13 parts by weight and especially 3 to 11 parts by weight of at least one compound of formula (I), particularly a compound of formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or a compound of formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide) and 0.1 to 0.5 parts by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane. The content of diphenylguanidine and / or substituted diphenylguanidine is up to 0.4 parts by weight, preferably 0.1 to 0.2 parts by weight, particularly preferably 0.05 to 0.1 parts by weight and very particularly preferably 0.001 to 0.04 parts by weight, based on 100 parts by weight of total rubber in each case.

[0176] The present invention further provides a method for producing a rubber compound according to the invention, which involves mixing at least one of the rubbers generally listed or preferred above with at least one of the fillers generally listed or preferred above and at least one compound of formula (I) and optionally with at least one of the reinforcing additives generally listed or preferred above, optionally one or more of the curing accelerators generally listed or preferred above, optionally one or more of the auxiliary accelerators generally listed or preferred above, and optionally one or more of the aforementioned rubber additives in general and preferred amounts specified for these additives, and heating the resulting mixture to a temperature in the range of 60°C to 200°C, particularly preferably from 90°C to 180°C.

[0177] The production of the rubber compound according to the invention typically employs at least one filler in 10 to 190 parts by weight, preferably 30 to 150 parts by weight and particularly preferably 50 to 130 parts by weight per 100 parts by weight of total rubber, and at least one compound of formula (I) in 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 2 to 10 parts by weight and very particularly preferably 3 to 8 parts by weight, and optionally one or more of the above-mentioned additives (in the amounts specified for these additives).

[0178] The rubber compound according to the invention can alternatively be produced by mixing at least one compound of formula (I) (where x = 2) with sulfur and at least one rubber and at least one filler at a temperature of 100°C to 200°C, preferably 130°C to 180°C. In this alternative method, the incorporation of additional sulfur atoms into the compound of formula (I) (where x = 2) is carried out in situ, thereby forming the compound of formula (I) according to the invention (where x = 2 to 8 and the number average of x is 4).

[0179] The production of the rubber compound according to the invention is carried out in a conventional manner in known mixing equipment, such as roller mixers, internal mixers, and mixing extruders, at a melting temperature of 60°C to 200°C, preferably 100°C to 200°C, and for 1 to 1000 seconds. -1 The shearing rate was [value].

[0180] The addition of the compound of formula (I) and the filler is preferably carried out in the first part of the mixing operation at a melting temperature of 60°C to 200°C, preferably 100°C to 200°C, and at the listed shear rates. However, the addition may also be carried out in a subsequent part of the mixing operation at a lower temperature (40°C to 130°C, preferably 40°C to 100°C), for example, together with sulfur and a curing accelerator.

[0181] The present invention further provides a method for curing the rubber compound of the present invention, preferably carried out at a melting temperature of 100°C to 200°C, particularly preferably 130°C to 180°C. In a preferred embodiment, curing is carried out under a pressure of 10 to 200 bar.

[0182] The present invention also includes rubber-cured products obtainable by curing the rubber mixtures of the present invention. These cured products, especially when used in tires, offer the benefits of excellent characteristic curves and unexpectedly low rolling resistance.

[0183] The rubber-cured products according to the invention are suitable for producing molded articles with improved properties, such as cable sheaths, hoses, drive belts, conveyor belts, roller covers, tires, shoe soles, seals and damping elements, and are particularly preferred for producing tires.

[0184] The present invention further provides the use of the compound of formula (I) in the production of rubber mixtures and their cured products. Detailed Implementation

[0185] Example

[0186] The present invention will be illustrated by the following examples, but is not limited thereto.

[0187] Determination of the properties of rubber compounds / cured products:

[0188] Rheometer (curing apparatus) complete curing time, 170℃ / t95:

[0189] MDR (moving die rheometer) curing characteristic curves and related analytical data were measured on an MDR 2000 Monsanto rheometer according to ASTM D5289-95. The time for at least 95% crosslinking of the rubber was determined as the complete curing time. The selected temperature was 170°C.

[0190] Determining hardness:

[0191] To determine the hardness of the rubber compound according to the invention, rolled sheets with a thickness of 6 mm were produced from the rubber compound according to the formulation in Table 1. Test samples with a diameter of 35 mm were cut from the rolled sheets, and their Shore A hardness was determined using a digital Shore hardness tester (Zwick GmbH & Co. KG, Ulm). The hardness of the cured rubber product provides a primary indication of its stiffness.

[0192] Tensile test:

[0193] Tensile testing is used directly to determine the load limit of the elastomer and is performed according to DIN 53504. The elongation at break is obtained by dividing the longitudinal elongation at break by the initial length. In addition, the force required to reach a specific elongation level (typically 50%, 100%, 200%, and 300%) is determined and expressed as a stress value (tensile strength at a specified elongation of 300% or modulus 300).

[0194] Dynamic damping:

[0195] Dynamic testing methods are used to characterize the deformation behavior of elastomers under periodically varying loads. An externally applied voltage alters the conformation of the polymer chains. The loss factor tanδ is determined indirectly by the ratio of the loss modulus G” to the storage modulus G’. The loss factor tanδ at 60°C is related to rolling resistance and should be as low as possible. The loss factor tanδ at 0°C is related to wet grip and should be as high as possible.

[0196] List of raw materials, abbreviations, and manufacturers

[0197]

[0198]

[0199] Production of organosilicon polysulfides

[0200] Example 1a:Production of bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide

[0201] First, 28.54 g (0.5 mol) of sodium polysulfide was placed in anhydrous methanol and heated to boiling under inert conditions. Then, 401.02 g (1.0 mol) of bis(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl chloride was added and the reaction mixture was heated under reflux for 1.5 hours.

[0202] Once the reaction is complete, the precipitated sodium chloride is filtered out and the solvent methanol is removed by distillation under vacuum. The distillation residue contains bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl] polysulfide.

[0203] Yield: 82% of theoretical value

[0204] Example 1b: Production of bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl] polysulfide

[0205] The production of bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl] polysulfide was carried out in a manner similar to Example 1a, except that 1.0 mol (415.04 g) of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl chloride was used instead of 1.0 mol of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl chloride.

[0206] Yield: 80% of theoretical value

[0207] Production of starting compounds

[0208] Example 1c: Production of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl chloride

[0209]

[0210] First, 0.025g of ruthenium catalyst Ru3(CO) was added. 12100 ppm Ru and 191.45 g (0.590 mol) of bis(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane were charged into a reaction vessel. The reaction mixture was heated to 76 °C under reflux, and 28.16 g (0.368 mol) of allyl chloride (Aldrich, CAS No. 107-05-1) was added dropwise over a 30-minute period. After the reaction mixture was heated to 80 °C for 90 minutes, analysis by gas chromatography confirmed that allyl chloride had undergone complete conversion. The target compound was obtained in 95% of the theoretical yield after purification by distillation under high vacuum.

[0211] Example 1d: Production of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl chloride

[0212]

[0213] First, 0.0249g of ruthenium catalyst Ru3(CO) was added. 12 100 ppm Ru and 191.45 g (0.590 mol) of bis(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane were charged into a reaction vessel. The reaction mixture was heated to 76 °C under reflux, and 33.32 g (0.368 mol) of isobutylene chloride (Aldrich, CAS No. 563-47-3) was added dropwise over a 30-minute period. After the reaction mixture was heated to 80 °C for 90 minutes, analysis by gas chromatography confirmed that allyl chloride had undergone complete conversion. The target compound was obtained in 94% of the theoretical yield after purification by distillation under high vacuum.

[0214] Example 1e Production of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane

[0215] First, 94.62 g (1.0 mol) of dichloromethylsilane (CAS No.: 1066-35-9) (Sigma-Aldrich) was added to a reaction vessel and heated to 70 °C under reflux. Then, 292.96 g (1.1 mol) of anhydrous Desmophen 1990 (Covestro AG) was added over a 4.5-hour period. The resulting HCl gas was passed through a cooler into an HCl trap (water + NaOH). The reaction mixture was then stirred at 80 °C under a nitrogen atmosphere for one hour.

[0216] In this way, di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane was obtained with a theoretical yield of 97%.

[0217] Production of rubber compounds

[0218] Example 1

[0219] Rubber mixtures A and B of the present invention, and a non-inventive rubber mixture control 1, were produced according to the formulations reported in Table 1. Compounds bis(triethoxysilylpropyl)tetrasulfide (TESPT) and compounds of formulas (Ia) and (Ib) were used in equimolar amounts in each case. However, to achieve comparable crosslinking densities important for modulus 300, elongation at break, and strength, slightly higher amounts of sulfur were added in the cases of compounds of formulas (Ia) and (Ib). The mixtures were produced in a kneader at an internal temperature of 150°C. The sulfur and accelerator were then mixed on rollers at 50°C. To achieve curing, the mixtures were heated to 170°C in a heatable press for 30 minutes.

[0220] The properties of the rubber mixtures and cured products of mixtures A, B and control 1 were tested according to the methods specified above.

[0221] It is evident from the test data that the rubber mixtures of the present invention in Examples A and B have significantly lower mixing viscosity and thus result in a significantly more advantageous production of cured products compared to the non-inventive rubber mixture of Control 1.

[0222] In addition to improved manufacturability of the cured products, the rubber compounds of the present invention also exhibit improved dynamic damping (measured as loss factor tanδ) at 60°C, which is related to the rolling resistance of the tire, with lower values ​​being advantageous. Surprisingly, in the cases of rubber compounds A and B of the present invention, one of the main drawbacks of rubber compounds containing the additive TESPT, namely the so-called increasing modulus of the crosslinking curve, does not occur. This results in a simplified specification of the complete curing time without constantly altering the dynamic mechanical curing properties. Further advantages in the production (curing) of molded articles can be attributed to the shortened complete curing time (t95) of the rubber compounds of the present invention.

[0223] Table 1

[0224]

[0225] Example 2

[0226] Rubber mixtures C and D of the present invention, and a non-inventive rubber mixture control 1, were produced according to the formulations reported in Table 2. Compounds bis(triethoxysilylpropyl)tetrasulfide (TESPT) and compounds of formulas (Ia) and (Ib) were used in equimolar amounts in each case. However, to achieve comparable crosslinking densities important for modulus 300, elongation at break, and strength, slightly higher amounts of sulfur were added in the cases of compounds of formulas (Ia) and (Ib).

[0227] Furthermore, in the rubber mixtures C and D of the present invention, the auxiliary accelerator DPG is used in each case. replace.

[0228] The mixture is produced in a kneader at an internal temperature of 150°C. The sulfur and accelerator are then mixed on rollers at 50°C. To achieve curing, the mixture is heated to 170°C in a heatable press for 30 minutes.

[0229] The properties of the rubber mixtures and cured products of mixtures C, D and control 1 were tested according to the methods specified above.

[0230] The test data clearly show that when used in rubber mixtures C and D of the present invention... When used as a DPG substitute, after the first mixing stage (5-stage mixing process), a lower mixture viscosity and improved scorch resistance (longer scorch time) were achieved compared to the non-inventive rubber mixture of Control 1. The complete curing time T95 was significantly reduced compared to Control 1.

[0231] In use When replacing DPG, the characteristic curves of the mechanical properties of the compounds of this invention remain largely undamaged in terms of hardness, modulus 300, elongation at break, and tensile strength. Resilience at 60°C is significantly increased, accompanied by a smaller loss factor tanδ at 60°C. This improvement indicates a reduction in rolling resistance.

[0232] Table 2

[0233]

[0234]

[0235] in conclusion:

[0236] The organosilicon polysulfides of formula (I) of the present invention can be used to produce the rubber compounds of the present invention, which have improved mixing properties, such as relatively low mixing viscosity. Cured products produced from the rubber compounds of the present invention have good strength and significantly improved elasticity (at 60°C). Furthermore, tires produced from the cured products are characterized by low rolling resistance.

Claims

1. A compound of formula (I) (I) in R 1 R 3 R 6 and R 8 Same or different and indicating C1-C4-alkyl, R 4 and R 5 The same or different and indicating hydrogen or C1-C4-alkyl, R 2 and R 7 The following formula represents a group (A) in a, b, and c are each independently 0, 1, 2, or 3. The condition is that the sum of a + b + c has a value between 3 and 6. and x is an integer from 2 to 8.

2. The compound according to claim 1, characterized in that, In equation (I) R 1 R 3 R 6 and R 8 The same or different and indicating methyl or ethyl, R 4 and R 5 The same or different and indicating hydrogen, methyl or ethyl, R 2 and R 7 The group representing formula (A), in a is 1 or 2. b is 1 or 2. c is 1 or 2 The condition is that the sum of a + b + c has a value between 3 and 6. and x is an integer from 2 to 8.

3. The compound according to claim 1 or 2, characterized in that, They conform to the following formula (him) in x is an integer from 2 to 8. Or the following formula (One) in x is an integer from 2 to 8.

4. The compound according to claim 1 or 2, characterized in that, a, b, and c are each 1, and the sum of a + b + c is 3.

5. A mixture comprising at least two compounds of formula (I) according to claim 1, wherein, Substituent R 1 To R 8 And x has the definition specified in claim 1, and they are different at least in the value of x, wherein the number of sulfur atoms x is the same as the number of sulfur atoms x. The value ranges from 3.6 to 4.

4.

6. The mixture according to claim 5, characterized in that, The number average of the number of sulfur atoms x It is 4.

0.

7. A method for producing the compound according to claim 1, characterized in that, The method comprises reacting at least two haloalkylsilyl ethers of formula (II) in the presence of at least one alcohol solvent. (II) in R 9 Represents group R 4 or R 5 , R 10 Represents group R 3 or R 6 , R 11 Represents group R 2 or R 7 and R 12 Represents group R 1 or R 8 , Among these groups R 1 To R 8 Having the definition specified in claim 1, and Hal represents halogen. With at least one metal polysulfide of formula (III) S x M2 (III) in x has the definition specified in claim 1. and M represents a metal ion from the group consisting of lithium, sodium, and potassium.

8. A method for producing the mixture according to claim 5, characterized in that, The method comprises reacting at least two haloalkylsilyl ethers of formula (II) in the presence of at least one alcohol solvent. (II) in R 9 Represents group R 4 or R 5 , R 10 Represents group R 3 or R 6 , R 11 Represents group R 2 or R 7 and R 12 Represents group R 1 or R 8 , Among these groups R 1 To R 8 Having the definition specified in claim 1, and Hal represents halogen. With at least one metal polysulfide of formula (III) S x M2 (III) in x has the definition specified in claim 5. and M represents a metal ion from the group consisting of lithium, sodium, and potassium.

9. A haloalkylsilyl ether of formula (II) (II) in R 9 Represents group R 4 Or R 5 , R 10 Represents group R 3 Or R 6 , R 11 Represents group R 2 Or R 7 and R 12 Represents group R 1 Or R 8 , Among these groups R 1 To R 8 Having the definition specified in claim 1, and Hal represents halogen.

10. A rubber compound comprising at least one rubber, at least one filler and at least one compound of formula (I) according to any one of claims 1 to 4.

11. The rubber compound according to claim 10, characterized in that, The rubber mixture comprises a total of 0.1 to 15 parts by weight of the compound of formula (I) and 10 to 190 parts by weight of at least one filler, based on a total of 100 parts by weight of rubber in each case.

12. The rubber compound according to claim 10 or 11, characterized in that, The rubber mixture contains at least one SBR rubber in the form of a styrene / butadiene copolymer having a styrene content of 1% to 60% by weight, optionally one or more BR rubbers and / or at least one natural rubber.

13. The rubber compound according to claim 10 or 11, characterized in that, The rubber compound contains at least one hydroxyl-containing oxidizing filler, which is from the group consisting of fillers having a molecular weight of 5 to 1000 μm as measured according to DIN 66131. 2 Silica with a BET specific surface area of ​​ / g and a primary particle size of 100 to 400 nm, wherein these silicas optionally also exist in the form of a mixed oxide with other metal oxides; and having a primary particle size of 20 to 400 nm as measured according to DIN 66131. 2 Synthetic silicates with a BET specific surface area of ​​ / g and a primary particle size of 10 to 400 nm.

14. The rubber compound according to claim 10 or 11, characterized in that, The rubber compound contains at least one component having a content measured according to DIN 66131 in the range of 20 to 200 μm. 2 Carbon black with BET specific surface area in the range of / g.

15. The rubber compound according to claim 10 or 11, characterized in that, The rubber compound contains at least one crosslinking agent derived from the group consisting of sulfur and sulfur donors and metal oxides.

16. The rubber compound according to claim 10 or 11, characterized in that, The rubber compound contains at least one curing accelerator from the group consisting of mercaptobenzothiazole, mercaptosulfonamide, thiocarbamate, thiocarbonate and dithiophosphate, and sulfur donor.

17. The rubber compound according to claim 10 or 11, characterized in that, The rubber compound contains at least one auxiliary accelerator from the group consisting of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane, TBzTD (tetrabenzylthiuram disulfide) and dithiophosphate.

18. The rubber compound according to claim 10 or 11, characterized in that, Based on a total rubber volume of 100 parts by weight, the rubber mixture has a content of up to 0.4 parts by weight of diphenylguanidine and / or substituted diphenylguanidine.

19. The rubber compound according to claim 10 or 11, characterized in that, Based on a total rubber volume of 100 parts by weight, the rubber mixture has a content of 0.001 to 0.04 parts by weight of diphenylguanidine and / or substituted diphenylguanidine.

20. A method for producing a rubber compound according to any one of claims 10 to 19, characterized in that, The method comprises mixing at least one rubber with at least one filler and at least one compound of formula (I) according to any one of claims 1 to 4 and heating the mixture to a temperature in the range of 60°C to 200°C.

21. A method for producing a rubber compound according to any one of claims 10 to 19, characterized in that, The method comprises mixing at least one rubber, at least one filler, and at least one compound of formula (I) according to claim 1, wherein x is 2, with sulfur at a temperature ranging from 100°C to 200°C.

22. A method for producing a rubber-cured product, which is carried out by curing a rubber mixture according to any one of claims 10 to 19.

23. Use of the rubber compound according to any one of claims 10 to 19 for the production of cured products.

24. A cured product obtained by curing a rubber mixture according to any one of claims 10 to 19.

25. A molded article comprising one or more cured products according to claim 24.

26. Use of the compound of formula (I) according to any one of claims 1 to 4 for the production of rubber mixtures according to any one of claims 10 to 19, cured products according to claim 24, or molded articles according to claim 25.

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