Organosilyl polysulfide and a rubber mixture containing the same

Abstract

Formula (I) JPEG2024525460000028.jpg29170 (in the formula, substituent R 1 ~R 8 and the index x has the definition specified herein. The novel organosilyl polysulfides of are highly suitable for producing rubber mixtures having improved mixing properties, the vulcanizates obtained therefrom and rubber products which are characterized by higher hardness, strength and elongation at break, and by lower rolling resistance of the tires produced therefrom.

Description

Technical Field

[0001] The present invention relates to novel organosilyl polysulfides, their use as reinforcing additives for rubbers, rubber mixtures containing these organosilyl polysulfides, the use of these organosilyl polysulfides for the production of these rubber mixtures, and vulcanizates and moldings obtainable from these rubber mixtures, in particular tires.

Background Art

[0002] Sulfur-containing organosilicon compounds that can be used as reinforcing additives in rubber mixtures are known. For example, (Patent Document 1), (Patent Document 2) and (Patent Document 3) describe sulfur-containing organosilanes as reinforcing additives for silica-containing rubber vulcanizates, especially for tire applications. The sulfur-containing organosilanes disclosed therein are derived from bis(trialkoxysilylalkyl)polysulfides, and for example, bis(triethoxysilylpropyl)tetrasulfide (TESPT) is clearly described.

[0003] (Patent Document 4) also discloses a reinforcing additive based on an organosilane derived from a trialkoxysilylpropyl compound. The disadvantages of these compounds known from the prior art are that the hysteresis loss decreases not only at high temperatures (about 60 °C, correlated with rolling resistance) but also at low temperatures (0 °C). The decrease in hysteresis loss is theoretically desirable because it results in a decrease in the rolling resistance of automobile tires and thus lower fuel consumption of the vehicle. However, it is known that low hysteresis at low temperatures (0 °C to 20 °C) is associated with poor wet skid resistance in automobile tires. Therefore, it is difficult to reconcile both requirements, namely low rolling resistance and good wet skid resistance.

[0004] (Patent Document 5) also describes the use of sulfur-containing organosilanes as adhesion promoters in rubber mixtures for the production of highly silica-filled tire treads. Among them, the combination of a special silane-modified rubber, a silica filler, and an adhesion promoter based on a special trialkoxyalkyl polysulfide makes it possible to reduce the rolling resistance of the tire. However, even in these tire mixtures, it is clear that the above-mentioned adhesion promoter not only reduces the rolling resistance but also decreases the wet grip.

[0005] (Patent Document 6) similarly discloses the use of a specific bis-alkoxy / alkyl-substituted silylmethylene polysulfide as a reinforcing additive for rubber mixtures having good rolling resistance and good wet grip. The disadvantages here include that the raw materials used to produce the reinforcing additive require expensive and inconvenient production by photochlorination, and also that the rubber exhibits a significant deterioration in performance characteristics such as strength, elongation at break, and hardness.

[0006] (Patent Document 7) discloses the use of bis(dimethylethoxysilylisobutylene) polysulfide as a reinforcing additive for rubber mixtures having good rolling resistance and good wet grip characteristics. However, using these compounds in tire production results in the release of 2 moles of ethanol per mole, which can actually be disadvantageous.

Prior Art Documents

Patent Documents

[0007]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

[0008] Accordingly, it is an object of the present invention to provide a novel reinforcing additive for rubbers based on sulfur-containing organosilicon compounds and a novel rubber mixture that overcomes the above-mentioned disadvantages of the prior art. [Means for Solving the Problems]

[0009] Surprisingly, certain organosilyl polysulfides, each having a propylene group or each having a propylene group branched at the 2-position as a spacer between silicon and sulfur atoms, are very suitable as reinforcing additives for rubber mixtures without involving the vulcanization of rubber mixtures that results in the emission of volatile organic components (VOCs).

[0010] The novel organosilyl polysulfide provides a fast complete vulcanization time (T95) for the rubber mixture and, in the vulcanizate obtainable therefrom, advantageous temperature-dependent hysteresis characteristics and positive performance characteristics, such as high strength and high elongation at break. Tires manufactured from these vulcanizates are particularly characterized by low rolling resistance and good wet grip. Furthermore, the novel organosilyl polysulfide is characterized by a very advantageous low mixing viscosity and thus enables the production of simpler mixtures.

[0011] Accordingly, the present invention provides the following formula (I) [Chemical Formula] (wherein R 1 、R3 , R 6 and R 8 are the same or different and represent C1-C4-alkyl, R 4 and R 5 are the same or different and represent hydrogen or C1-C4-alkyl, R 2 and R 7 represent a group of the formula

Chemical formula

Mode for Carrying Out the Invention

[0012] In the formula, R 1 , R 3 , R 6 and R 8 are the same or different and represent methyl or ethyl, R 4 and R 5 are the same or different and represent hydrogen, methyl, or ethyl, R 2 and R 7 represent a group of formula (A), wherein, a is 1 or 2, b is 1 or 2, c is 1 or 2, provided that the sum of a + b + c has a value of 3 to 6, preferably 3 or 4, particularly preferably 3, and x is an integer from 2 to 8, and the organosilyl polysulfide of formula (I) is preferred.

[0013] In the formula, R 1 , R 3 , R 6 and R 8 represent methyl, R 4 and R 5 are the same or different and represent hydrogen or methyl, R 2 and R 7 represent a group of formula (A), in which a is 1 or 2, b is 1 or 2, c is 1 or 2, provided that the sum of a + b + c is 3 or 4, and x is an integer from 2 to 8, and the organosilyl polysulfide of formula (I) is particularly preferred.

[0014] In the formula, R 1 , R 3 , R 6 and R 8 represent methyl, R 4 and R 5 are the same and represent hydrogen or methyl, R 2 and R 7 represent a group of formula (A), in which a, b and c are 1, and x is an integer from 2 to 8, and the organosilyl polysulfide of formula (I) is very particularly preferred.

[0015] The organosilyl polysulfides of the following formulas (Ia) and (Ib) are particularly preferred.

Chemical formula

Chemical formula

[0016] It is known to those skilled in the art that organosilyl polysulfide can undergo disproportionation under the influence of temperature and / or solvent. Therefore, the organosilyl polysulfide according to the present invention is mostly in the form of a mixture, and the number of sulfur atoms in the organosilyl polysulfide is generally in the range of a number average of 3.6 to 4.4, preferably 3.8 to 4.2, particularly 4.0.

[0017] The present invention relates to a mixture containing at least two organosilyl polysulfides of formula (I) (wherein the substituents R 1 ~R 8 and x have the above general and preferred definitions and are different at least in the value of x), and the number average of the number of sulfur atoms x

Number

[0018] Particularly preferred is a mixture containing at least two organosilyl polysulfides of formula (Ia) and / or formula (Ib) that are different with respect to the value x of the number of sulfur atoms, and the number average of the number of sulfur atoms x

Number

[0019] The organosilyl polysulfide of formula (I) according to the present invention has the following formula (II)

Chemical

[0020] in the presence of at least one alcoholic solvent.

[0021] The method for producing the organosilyl polysulfide is known in principle. The organosilyl polysulfide of formula (I) according to the present invention can be produced by analogy from known methods (such as those described in German Patent Application Publication No. A2141159).

[0022] ​​​​​​The method for producing an organosilyl polysulfide according to the present invention can be carried out over a wide temperature range. This is preferably carried out at a temperature in the range of -20°C to +90°C.

[0023] The method for producing an organosilyl polysulfide according to the present invention is preferably carried out in the presence of at least one alcohol from the group consisting of methanol, ethanol, n-propanol, i-propanol, i-butanol, amyl alcohol, hexyl alcohol, n-octanol, i-octanol, ethylene glycol, 1,2- and 1,3-propylene glycol, 1,4-butanediol and / or 1,6-hexanediol.

[0024] The method for producing an organosilyl polysulfide according to the present invention can be carried out over a wide pressure range. This is generally carried out at a pressure of 0.9 to 1.1 bar, preferably at standard pressure.

[0025] The production of the organosilyl polysulfide (I) according to the present invention generally involves initially charging a metal polysulfide of formula (III) into anhydrous alcohol, preferably anhydrous methanol, heating the mixture to boiling under inert conditions, and then adding at least two haloalkylsilyl ethers of formula (II). Upon completion of the reaction, the precipitated alkali metal salt is filtered off as a by-product, the solvent is removed from the compound of formula (I) by distillation, and the remaining bottom product is isolated in pure form in a yield of >85%.

[0026] The haloalkylsilyl ether of formula (II) is novel and likewise forms part of the subject matter of the present invention.

[0027] The method for producing a haloalkylsilyl ether is known in principle.

[0028] The haloalkylsilyl ether of formula (II) according to the present invention has the following formula (IV)

Chemical formula

Chemical formula

[0029] and at least one ruthenium catalyst can be produced in a known manner, for example, similar to the method described in European Patent Application Publication No. A0669338.

[0030] Generally, 1.15 to 2 moles, preferably 1.6 to 2.0 moles of the silane of formula (V) are used per mole of the haloallyl compound of formula (IV).

[0031] Suitable ruthenium catalysts preferably include the compounds disclosed in European Patent Application Publication No. A0669338. The ruthenium catalyst Ru3(CO) 12 is particularly suitable for producing the haloalkylsilyl ether of formula (II) according to the present invention.

[0032] Generally, 10 to 200 ppm, preferably 15 to 100 ppm of at least one ruthenium catalyst is used per mole of the haloallyl compound of formula (IV).

[0033] The reaction between the haloallyl compound of formula (IV) and the silane of formula (V) is generally carried out at a temperature in the range of 20°C to 150°C, preferably 70°C to 90°C.

[0034] This reaction is generally carried out over a period of 1 to 100 hours, preferably 1.5 to 5 hours.

[0035] The progress of the reaction can be monitored by TLC (thin layer chromatography). When the reaction is complete, the haloalkylsilyl ether of formula (II) can be purified by distillation. This makes it possible to achieve a yield of up to 97%.

[0036] The haloallyl compound of formula (IV) is known and can be obtained, for example, as a commercially available product from Aldrich (CAS number: 107 - 05 - 1 or CAS number: 563 - 47 - 3).

[0037] The silane of formula (V) is the following formula (VI)

Chemical formula

[0038] The silane of formula (VI) is known and can be obtained, for example, as a commercially available product from Sigma - Aldrich.

[0039] The present invention relates to at least one rubber and the following formula (I)

Chemical formula

[0040] Generally, the total content of the compound of formula (I) in the rubber mixture according to the present invention is 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 2 to 13 parts by weight, very particularly preferably 3 to 11 parts by weight, based on the total amount of 100 parts by weight of rubber in each case.

[0041] The compound of formula (I) can be added to the rubber mixture in pure form or absorbed on another inert organic or inorganic carrier. Suitable carrier materials are, in particular, silica, natural or synthetic silicates, aluminum oxide and carbon black.

[0042] The rubber mixture according to the present invention contains at least one rubber.

[0043] It is preferred when the rubber mixture according to the present invention contains at least one natural rubber (NR) and / or synthetic rubber.

[0044] Suitable synthetic rubbers include, for example, BR - polybutadiene, ABR - butadiene / C1-C4-alkyl acrylate copolymer, CR - polychloroprene, IR - polyisoprene, SBR - styrene / butadiene copolymer having a styrene content of 1 to 60% by weight, preferably 20 to 50% by weight, IIR - isobutylene / isoprene copolymer, NBR - butadiene / acrylonitrile copolymer having an acrylonitrile content of 5% to 60% by weight, preferably 10 to 50% by weight, HNBR - partially or fully hydrogenated NBR rubber, EPDM - ethylene / propylene / diene copolymer, and mixtures of two or more of these rubbers is included.

[0045] Preferably, the rubber mixture according to the invention contains at least one SBR rubber, preferably a functionalized SBR rubber and optionally one or more BR rubbers in some cases.

[0046] According to the invention, the functionalized SBR rubber is an SBR rubber substituted with one or more functional groups, in particular carboxyl groups and / or mercaptan-containing groups, in the main chain and / or end groups.

[0047] Very particularly preferably, the rubber mixture according to the invention contains a mixture of SBR and BR rubbers in an SBR:BR weight ratio of 100:0 to 60:40.

[0048] In a further advantageous embodiment, the rubber mixture according to the invention contains at least one natural rubber.

[0049] Preferably, the rubber mixture according to the invention contains one or more fillers. Suitable fillers include, in principle, all fillers known from the prior art for this purpose.

[0050] Suitable active fillers include, in particular, hydroxyl-containing oxide-based compounds, such as certain silicas and also carbon black.

[0051] Generally, the rubber mixture according to the invention 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, based on a total of 100 parts by weight of rubber in each case.

[0052] Preferably, the rubber mixture according to the invention contains at least one hydroxyl-containing oxide-based filler.

[0053] Generally, the content of the hydroxyl-containing oxide filler in the rubber mixture 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, very particularly preferably 80 to 130 parts by weight, in each case based on a total filler content of 100 parts by weight.

[0054] Suitable hydroxyl-containing oxide fillers are preferably those from the following group. - silica having a specific surface area (BET) of 5 to 1000, preferably 20 to 400 m 2 / g and a primary particle size of 100 to 400 nm, optionally also in the form of a mixed oxide with other metal oxides, for example oxides of Al, Mg, Ca, Ba, Zn, Zr, Ti, and - synthetic silicates having a specific surface area (BET) of 20 to 400 m 2 / g and a primary particle diameter of 10 to 400 nm, such as aluminum silicate, alkaline earth metal silicates, for example magnesium silicate or calcium silicate.

[0055] The hydroxyl-containing oxide fillers present in the rubber mixture of the invention and from the group of silica can preferably be produced, for example, by precipitation of a silicate solution or by flame hydrolysis of silicon halides.

[0056] It is preferred if the rubber mixture according to the invention contains at least one hydroxyl-containing oxide filler selected from the group of silica having a specific surface area (BET) in the range of 20 to 400 m 2 / g in an amount of 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, in each case based on a total amount of 100 parts by weight of rubber.

[0057] The rubber mixture according to the invention can further contain at least one carbon black as filler.

[0058] It can be obtained by the lamp black, furnace black, or gas black method and has a specific surface area (BET) in the range of 20 to 200 m 2 / g of carbon black, such as SAF, ISAF, IISAF, HAF, FEF, or GPF carbon black, is preferred according to the present invention.

[0059] The rubber mixture according to the present invention generally contains at least one carbon black having a specific surface area (BET) in the range of 20 to 200 m 2 / g in an amount of 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight, based on the total amount of 100 parts by weight of rubber in each case.

[0060] All BET values relate to the specific surface area measured according to DIN66131. The reported primary particle size relates to the value determined by a scanning electron microscope.

[0061] In a preferred alternative embodiment, the rubber mixture according to the present invention contains, as a filler, at least one of the above-mentioned carbon blacks and at least one of the above-mentioned silicas.

[0062] In a particularly preferred alternative embodiment, the rubber mixture according to the present invention contains, in an amount of 20 to 120 parts by weight, preferably 30 to 100 parts by weight, particularly preferably 40 to 90 parts by weight, based on the total amount of 100 parts by weight of rubber in each case, at least one hydroxyl-containing oxide-based filler from the group of silicas having a specific surface area (BET) in the range of 20 to 400 m 2 / g, and at least one carbon black having a specific surface area (BET) in the range of 20 to 200 m 2 / g in an amount of 20 to 90 parts by weight, preferably 30 to 80 parts by weight, particularly preferably 40 to 70 parts by weight.

[0063] The rubber mixture of the present invention may contain one or more crosslinking agents.

[0064] Preferred crosslinking agents according to the invention are, in particular, sulfur and sulfur donors, and also metal oxides such as magnesium oxide and / or zinc oxide.

[0065] Sulfur can be used in the soluble or insoluble form of the element or in the form of a sulfur donor. Suitable sulfur donors include, for example, dithiomorpholine (DTDM), 2-morpholinodithiobenzothiazole (MBSS), caprolactam disulfide, dipentamethylenethiuram tetrasulfide (DPTT), and tetramethylthiuram disulfide (TMTD).

[0066] It is particularly preferred if the rubber mixture according to the invention contains at least one sulfur donor and / or sulfur, in particular sulfur.

[0067] The rubber mixture according to the invention generally contains at least one of the listed crosslinking agents in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based in each case on a total of 100 parts by weight of rubber.

[0068] The rubber mixture according to the invention can contain one or more vulcanization accelerators.

[0069] Preferred vulcanization accelerators according to the invention are mercaptobenzothiazoles, mercaptosulfenamides, thiocarbamates, thiocarbonates, and dithiophosphates, and also sulfur donors such as dithiocaprolactams, dithiomorpholines, and xanthates.

[0070] The rubber mixture according to the invention generally contains at least one of the listed vulcanization accelerators in an amount of 0.1 to 10 parts by weight, preferably 0.2 to 5 parts by weight, based in each case on a total of 100 parts by weight of rubber.

[0071] In addition to the compound of formula (I), the rubber mixture according to the invention can also contain one or more further reinforcing additives which are common for these purposes and are known from the prior art.

[0072] In addition to the above additives, the rubber mixture according to the invention may also contain further rubber auxiliaries well known to those skilled in the art, such as reaction accelerators, anti-aging stabilizers, heat stabilizers, light stabilizers, antiozonants, processing aids, plasticizers, tackifiers, blowing agents, dyes, pigments, waxes, extenders, organic acids, reaction retarders, metal oxides, activators such as triethanolamine, polyethylene glycol, hexanetriol, and fillers from the group of natural silicates such as kaolin and other naturally occurring silicas and furthermore glass fibers and glass fiber products in the form of, for example, mats, strands or microspheres.

[0073] The rubber mixture according to the invention contains the rubber auxiliaries listed in each case typically in an amount of 0.1 to 30 parts by weight, each based on a total amount of 100 parts by weight of rubber in each case, in amounts common for these auxiliaries.

[0074] The rubber mixture according to the invention may contain one or more secondary accelerators.

[0075] In silica-based rubber mixtures such as those used for tire production, diphenylguanidine (DPG) or structurally similar aromatic guanidines are typically used as secondary accelerators for the controlled adjustment of the crosslinking ratio and the mixture viscosity in the mixing process. However, a very important harmful characteristic associated with the use of DPG is that it releases aniline, which is suspected of being carcinogenic during vulcanization. Surprisingly, it has been found that in the rubber mixture of the present invention, DPG can advantageously be replaced by 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (trade name: Vulcuren®). Substitution of DPG by secondary accelerators such as TBzTD (tetrabenzylthiuram disulfide) or dithiophosphates is also possible.

[0076] Accordingly, the present invention also encompasses rubber mixtures essentially free of DPG.

[0077] The silica-based rubber mixture according to the present invention preferably contains at least one secondary accelerator from the group consisting of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (trade name: Vulcuren®), tetrabenzylthiuram disulfide (TBzTD), and dithiophosphate.

[0078] The rubber mixture according to the present invention generally contains at least one of the listed secondary accelerators in an amount of 0.1 to 1.0 part by weight, preferably 0.2 to 0.5 part by weight, based on the total amount of 100 parts by weight of rubber in each case.

[0079] Accordingly, the present invention also provides a rubber mixture of the present invention that is essentially free of diphenylguanidine and / or substituted diphenylguanidine, in particular having a content of diphenylguanidine and / or substituted diphenylguanidine of at most 0.4 part by weight, preferably 0.1 to 0.2 part by weight, particularly preferably 0.05 to 0.1 part by weight, very particularly preferably 0.001 to 0.04 part by weight, based on the total amount of 100 parts by weight of rubber in each case.

[0080] Preferred is a rubber mixture according to the present invention containing at least one rubber, at least one silica in an amount of 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, based on the total amount of 100 parts by weight of rubber in each case, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight of carbon black, and 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 2 to 10 parts by weight, especially 3 to 8 parts by weight of at least one compound of formula (I).

[0081] At least one rubber, in each case 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight of at least one silica, based on a total amount of 100 parts by weight of rubber, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight of carbon black, and 0.1 to 15 parts by weight, preferably 1 to 14 parts by weight, particularly preferably 2 to 13 parts by weight, in particular 3 to 11 parts by weight of at least one compound of formula (I), and 0.1 to 1.0 part by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (Vulcuren®) are likewise preferred rubber mixtures according to the invention.

[0082] At least one rubber, in particular at least one SBR rubber, preferably a functionalized SBR rubber and optionally in some cases one or more BR rubbers, in each case 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, in particular 5 to 1000 m 2 / g, preferably 20 to 400 m 2 / g of specific surface area (BET) and having a primary particle size of 100 to 400 nm of at least one silica, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight, in particular 20 to 200 m 2 / g range of specific surface area (BET) of carbon black and 0.1 to 15 parts by weight, preferably 1 to 14 parts by weight, particularly preferably 2 to 13 parts by weight, in particular 3 to 11 parts by weight of formula (I), in particular formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]tetrasulfide) and / or formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]tetrasulfide) of at least one compound are very particularly preferred rubber mixtures according to the invention.

[0083] At least one rubber, in particular at least one SBR rubber, preferably a functionalized SBR rubber and optionally in some cases one or more BR rubbers, in each case 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, in particular 5 to 1000 m 2 / g, preferably 20 to 400 m 2 / g of specific surface area (BET) and having a primary particle size of 100 to 400 nm, at least one silica, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight, in particular 20 to 200 m 2 / g range of specific surface area (BET) of carbon black, and 0.1 to 15 parts by weight, preferably 1 to 14 parts by weight, particularly preferably 2 to 13 parts by weight, in particular 3 to 11 parts by weight of formula (I), in particular formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide) of at least one compound and 0.1 to 0.5 parts by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (Vulcuren®) and at most 0.4 parts by weight, preferably 0.1 to 0.2 parts by weight, particularly preferably 0.05 to 0.1 parts by weight, very particularly preferably 0.001 to 0.04 parts by weight content of diphenylguanidine and / or substituted diphenylguanidine, the rubber mixture according to the invention is also very particularly preferred.

[0084] At least one natural rubber, in each case 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, in particular 5 to 1000 m 2 / g, preferably 20 to 400 m 2 / g of specific surface area (BET) and having a primary particle size of 100 to 400 nm, at least one silica, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight, in particular 20 to 200 m 2A rubber mixture according to the invention containing carbon black having a specific surface area (BET) in the range of / g, and 0.1 to 15 parts by weight, preferably 1 to 14 parts by weight, particularly preferably 2 to 13 parts by weight, especially 3 to 11 parts by weight of formula (I), in particular formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide) of at least one compound is also very particularly preferred.

[0085] At least one natural rubber, 5 to 150 parts by weight, preferably 50 to 140 parts by weight, particularly preferably 80 to 130 parts by weight, in particular 5 to 1000 m 2 / g, preferably 20 to 400 m 2 At least one silica having a specific surface area (BET) in the range of / g and a primary particle size of 100 to 400 nm, 0 to 40 parts by weight, preferably 0 to 30 parts by weight, particularly preferably 0 to 20 parts by weight, in particular 20 to 200 m 2 Carbon black having a specific surface area (BET) in the range of / g, and 0.1 to 15 parts by weight, preferably 1 to 14 parts by weight, particularly preferably 2 to 13 parts by weight, especially 3 to 11 parts by weight of formula (I), in particular formula (Ia) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide) and / or formula (Ib) (bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide) of at least one compound and 0.1 to 0.5 parts by weight of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane (Vulcuren®), and 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, very particularly preferably 0.001 to 0.04 parts by weight of diphenylguanidine and / or substituted diphenylguanidine content of a rubber mixture according to the invention is also very particularly preferred.

[0086] The present invention generally comprises at least one of the rubbers listed generally or as preferred above, at least one of the fillers listed generally or as preferred above, and at least one compound of formula (I), and optionally at least one of the reinforcing additives listed generally or as preferred above in some cases, one or more of the vulcanization accelerators listed generally or as preferred above in some cases, and one or more of the secondary accelerators listed generally or as preferred above in some cases, and optionally one or more of the above rubber auxiliaries, and mixes them in the general and preferred amounts specified for these additives, and further provides a method for producing a rubber mixture according to the present invention by heating the thus obtained mixture to a temperature in the range of 60 °C to 200 °C, particularly preferably 90 °C to 180 °C.

[0087] The production of the rubber mixture according to the present invention typically uses at least one filler in an amount of 10 to 190 parts by weight, preferably 30 to 150 parts by weight, particularly preferably 50 to 130 parts by weight per 100 parts by weight of the total amount of rubber, at least one compound of formula (I) in an amount of 0.1 to 15 parts by weight, preferably 1 to 12 parts by weight, particularly preferably 2 to 10 parts by weight, very particularly preferably 3 to 8 parts by weight, and optionally one or more of the above additives in the amounts specified for these additives in some cases.

[0088] The rubber mixture according to the present invention can alternatively be produced by mixing at least one compound of formula (I) (where x = 2), sulfur, 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, whereby a compound of formula (I) according to the present invention (where x = 2 to 8 and the number average of x = 4) is formed.

[0089] The production of the rubber mixture according to the present invention is carried out in a known mixing device, such as a roller, an internal mixer, and a mixing extruder, in a general manner at a melting temperature of 60°C to 200°C, preferably 100°C to 200°C and a shear rate of 1 to 1000 sec. -1 It is carried out in a general manner at a shear rate of.

[0090] The addition of the compound of formula (I) and the addition of the filler are preferably carried out at a melting temperature of 60°C to 200°C, preferably 100°C to 200°C and the listed shear rates in the first part of the mixing operation. However, the addition can also be carried out at a lower temperature (40°C to 130°C, preferably 40°C to 100°C) in the later part of the mixing operation, for example, together with sulfur and a vulcanization accelerator.

[0091] The present invention further provides a method for vulcanizing the rubber mixture of the present invention, which is preferably carried out at a melting temperature of 100°C to 200°C, particularly preferably 130°C to 180°C. In a preferred embodiment, the vulcanization is carried out at a pressure of 10 to 200 bar.

[0092] The present invention also includes rubber vulcanizates obtainable by vulcanizing the rubber mixture of the present invention. These vulcanizates have excellent profile characteristics and unexpectedly low rolling resistance advantages, especially when used in tires.

[0093] The rubber vulcanizate according to the present invention is suitable for manufacturing molded articles with improved properties, for example, for manufacturing cable sheaths, hoses, drive belts, conveyor belts, roller covers, tires, shoe soles, sealing rings, and damping elements, and is particularly preferably suitable for manufacturing tires.

[0094] The present invention further provides the use of the compound of formula (I) for producing the rubber mixture and its vulcanizate.

Examples

[0095] The present invention is illustrated by the following examples, but is not limited thereto.

[0096] Determination of the properties of the rubber mixture / vulcanizate: Rheometer (Bulkameter) complete vulcanization time 170 °C / t95: The MDR (Moving Die Rheometer) vulcanization profile and associated analytical data are measured on an MDR 2000 Monsanto rheometer in accordance with ASTM D5289-95. The time at which 95% of the rubber is cross-linked is determined as the full vulcanization time. The selected temperature was 170 °C.

[0097] Determination of hardness: To determine the hardness of the rubber mixture according to the present invention, a roll sheet with a thickness of 6 mm was produced from the rubber mixture according to the formulation in Table 1. Test specimens with a diameter of 35 mm were cut from the roll sheet, and the Shore A hardness was determined using a digital Shore hardness tester (Zwick GmbH & Co. KG, Ulm). The hardness of the rubber vulcanizate is the first indicator of its hardness.

[0098] Tensile test: The tensile test is used directly to determine the load limit of the elastomer and is carried out in accordance with DIN 53504. The longitudinal break elongation is divided by the initial length to obtain the break elongation. Furthermore, the forces required to achieve specific elongation levels, usually 50%, 100%, 200%, and 300%, are also determined and expressed as stress values (tensile strength at a specific elongation of 300% or 300 modulus).

[0099] Dynamic damping: The dynamic test method is used to characterize the deformation behavior of the elastomer under a periodically changing load. The externally applied voltage changes the three-dimensional structure of the polymer chains. The loss factor tangent δ is determined indirectly by the ratio of the loss modulus G'' to the storage modulus G'. The loss factor tangent δ at 60 °C is related to the rolling resistance and should be as low as possible. The loss factor tangent δ at 0 °C is related to the wet grip and should be as high as possible.

[0100]

Table 1

[0101]

Table 2

[0102] Production of organosilyl polysulfides Example 1a: Production of Bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide 28.54 g (0.5 mol) of sodium polysulfide was first charged into anhydrous methanol and heated to boiling under inert conditions. Subsequently, 401.02 g (1.0 mol) of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl chloride was added, and the reaction mixture was heated for 1.5 hours while refluxing.

[0103] Upon completion of the reaction, the precipitated sodium chloride was filtered off, and the solvent methanol was removed by distillation under vacuum. The distillation residue contained bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl]polysulfide. Yield: 82% of the theoretical value

[0104] Example 1b: Production of Bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide The production of bis[di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl]polysulfide was carried out in the same manner as in 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. Yield: 80% of the theoretical value

[0105] Production of starting compounds Example 1c: Production of Di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylpropyl Chloride [Chemical formula] 0.025 g of ruthenium catalyst Ru3(CO) 12 (100 ppm of Ru) and 191.45 g (0.590 mol) of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane were initially charged into the 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 30 minutes. Allyl chloride was determined to be completely converted by analysis by gas chromatography after heating the reaction mixture at 80 °C for an additional 90 minutes. After purification by distillation under high vacuum, the target compound was obtained in a yield of 95% of theory.

[0106] Example 1d: Production of Di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilylisobutyl Chloride [Chemical formula] 0.0249 g of ruthenium catalyst Ru3(CO) 12 (100 ppm of Ru) and 191.45 g (0.590 mol) of di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane were initially charged into the reaction vessel. The reaction mixture was heated to 76 °C under reflux, and 33.32 g (0.368 mol) of isobutene chloride (Aldrich (CAS No.: 563 - 47 - 3)) was added dropwise over 30 minutes. Allyl chloride was determined to be completely converted by analysis by gas chromatography after heating the reaction mixture at 80 °C for an additional 90 minutes. After purification by distillation under high vacuum, the target compound was obtained in a yield of 94% of theory.

[0107] Example 1e : Production of Di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane 94.62 g (1.0 mol) of chlorodimethylsilane (CAS No.: 1066-35-9) (Sigma-Aldrich) was initially charged into the reaction vessel and heated to 70 °C under reflux. Subsequently, 292.96 g (1.1 mol) of anhydrous Desmophen 1990 (Covestro AG) was added over 4.5 hours. The resulting HCl gas was transferred via a cooler to an HCl trap (water + NaOH). The reaction mixture was then stirred at 80 °C for an additional 1 hour under a nitrogen atmosphere.

[0108] In this way, di(ethyleneoxyhydroxymethyl)ethyleneoxybutoxydimethylsilane was obtained in a yield of 97% of theory.

[0109] Production of rubber mixtures Example 1 The rubber mixtures A and B of the present invention and the rubber mixture comparative control 1 according to the present invention were produced according to the formulations reported in Table 1. The compound bis(triethoxysilylpropyl)tetrasulfide (TESPT) and the compounds of formulas (Ia) and (Ib) were used in equimolar amounts in each case. However, in order to achieve comparable crosslink densities that are meaningful for 300 modulus, elongation at break, and strength, a slightly higher amount of sulfur was added in the case of the compounds of formulas (Ia) and (Ib). The mixtures were produced in a kneader at an internal temperature of 150 °C. Sulfur and accelerators were subsequently incorporated on a roller at 50 °C. To achieve vulcanization, the mixture was heated in a heatable press at 170 °C for 30 minutes.

[0110] The testing of the properties of the rubber mixtures and the vulcanizates of mixtures A, B, and comparative control 1 was carried out by the method specified above.

[0111] It is clear from the test data that the rubber mixtures of the present invention in Examples A and B have a significantly lower mixing viscosity and thus result in a substantially more advantageous production of vulcanizates than the rubber mixture comparative control 1 according to the present invention.

[0112] In addition to the improved production possibility of the vulcanizate, the rubber mixtures of the present invention also show an improvement in dynamic damping at 60 °C (measured as the loss factor tangent δ), which correlates with the rolling resistance of the tire (a lower value is advantageous). It is an additional surprising fact that one of the major disadvantages of rubber mixtures containing the additive TESPT, namely the so-called marching modulus of the crosslinking curve, does not occur in the case of the rubber mixtures A and B of the present invention. This requires a simplified standard for the full vulcanization time without constantly changing the dynamic mechanical vulcanization properties. A further advantage in the production (vulcanization) of molded articles can result from the shortened full vulcanization time (t95) of the rubber mixtures of the present invention.

[0113]

Table 3

[0114]

Table 4

[0115] Example 2 The rubber mixtures C and D of the present invention and the comparative control 1, which is a rubber mixture not according to the present invention, were produced according to the formulations reported in Table 2. The compound bis(triethoxysilylpropyl)tetrasulfide (TESPT) and the compounds of formulas (Ia) and (Ib) were used in equimolar amounts in each case. However, in the case of the compounds of formulas (Ia) and (Ib), a slightly higher amount of sulfur was added in order to achieve a comparable crosslink density that is meaningful for 300 modulus, elongation at break and strength.

[0116] Furthermore, in the rubber mixtures C and D of the present invention, the secondary accelerator DPG was replaced in each case by VULCUREN®.

[0117] The mixture was produced in a kneader at an internal temperature of 150 °C. Sulfur and accelerators were subsequently incorporated onto the rollers at 50 °C. To achieve vulcanization, the mixture was heated in a heatable press at 170 °C for 30 minutes.

[0118] The testing of the properties of the rubber mixtures and the vulcanizates of mixtures C, D and Comparative Control 1 was carried out by the method specified above.

[0119] When using VULCUREN® as a DPG replacement in the rubber mixtures C and D of the present invention, it is clear from the test data that a lower mixture viscosity is achieved after the first mixing stage (5-stage mixing process), with improved scorch resistance (longer scorch time), compared to the non-invention rubber mixture of Comparative Control 1. The full vulcanization time T95 was significantly reduced compared to Comparative Control 1.

[0120] The profile of the mechanical properties of the compounds of the present invention with respect to hardness, 300 modulus, elongation at break and tensile strength remained almost unimpaired by the replacement of DPG with VULCUREN®. The rebound resilience at 60 °C increased significantly, accompanied by a smaller loss factor tangent delta at 60 °C. This improvement is an indicator of lower rolling resistance.

[0121]

Table 5

[0122]

Table 6

[0123] Conclusion: Using the organosilyl polysulfide of the present invention of formula (I), a rubber mixture of the present invention having improved mixing properties, for example, relatively low mixing viscosity, can be produced. The vulcanizate produced from the rubber mixture of the present invention has good strength and significantly increased elasticity (at 60 ° C.). The tire produced from the vulcanizate is further characterized by low rolling resistance.

Claims

1. The following formula (I) 【Chemical Formula 1】 (In the formula,[[]] R １ , R ３ , R ６ and R ８ are the same or different and each represents C １ ~C ４ -alkyl,[[]] R ４ and R ５ are the same or different and each represents hydrogen or C １ ~C ４ -alkyl,[[]] R ２ and R ７ represent a group of the following formula 【Chemical Formula 2】 In the formula, a, b and c are each independently 0, 1, 2 or 3, provided that the sum of a + b + c is a value of 3 to 6, and x is an integer of 2 to 8) of the compound.

2. In formula (I), R １ , R ３ , R ６ and R ８ are the same or different and each represents methyl or ethyl,[[]] R ４ and R ５ are the same or different and each represents hydrogen, methyl or ethyl,[[]] R ２ and R ７ represent a group of formula (A). In the formula, a is 1 or 2, b is 1 or 2, c is 1 or 2, provided that the sum of a + b + c is a value of 3 to 6, and x is an integer of 2 to 8, characterized in that the compound according to claim 1.

3. The following formula 【Chemical Formula 3】 (wherein x is an integer from 2 to 8) of the compound, or the following formula 【Chemical Formula 4】 (wherein x is an integer from 2 to 8) The compound according to claim 2, characterized in that it is a compound of

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

5. A mixture containing at least two organosilyl polysulfides of formula (I) according to claim 1, wherein in formula (I), the substituents R １ ~R ８ and x have the definitions specified in claim 1, and at least the value of x is different, where the number average of the number of sulfur atoms x 【Number 1】 is 3.6 to 4.4, the mixture.

6. A method for producing the compound according to any one of claims 1 to 4 or the mixture according to claim 5, comprising the following formula (II) 【Chemical Formula 5】 (wherein R ９ represents the group R ４ or R ５ represents, R １０ represents the group R ３ or R ６ represents, R １１ represents the group R ２ or R ７ represents, and R １２ represents the group R １ or R ８ represents, the groups R １ ~R ８ have the definitions specified in claim 1, and (wherein Hal represents a halogen) At least two haloalkylsilyl ethers of the following formula (III) S ｘ M ２ (III) (wherein, x has the definition specified in claim 1 and M represents a metal ion from the group of lithium, sodium, and potassium) reacting with at least one metal polysulfide in the presence of at least one alcoholic solvent. A method characterized by comprising.

7. The following formula (II) 【Chemical formula 6】 (wherein, R ９ represents group R ４ or R ５ represents, R １０ represents group R ３ or R ６ represents, R １１ represents group R ２ or R ７ represents, and R １２ represents group R １ or R ８ represents, said group R １ to R ８ has the definition specified in claim 1 and Hal represents a halogen) haloalkylsilyl ether of.

8. A rubber mixture containing at least one rubber, at least one filler, and at least one compound of formula (I) according to claim 1.

9. Based on a total amount of 100 parts by weight of rubber in each case, comprising 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. The rubber mixture according to claim 8, characterized by.

10. The rubber mixture according to claim 8, characterized in that it contains at least one SBR rubber in the form of a styrene / butadiene copolymer having a styrene content of 1% to 60% by weight.

11. 5 to 1000 m ２ The rubber mixture according to claim 8, characterized in that it contains at least one hydroxyl-containing oxide filler from the group consisting of silica having a specific surface area (BET measured in accordance with DIN 66131) of 5 to 1000 m² / g and a primary particle size of 100 to 400 nm.

12. 20 to 200 m ２ The rubber mixture according to claim 8, characterized in that it contains at least one carbon black having a specific surface area (BET measured in accordance with DIN 66131) in the range of 20 to 200 m² / g.

13. The rubber mixture according to claim 8, characterized in that it contains at least one crosslinking agent from the group consisting of sulfur, sulfur donors, and metal oxides.

14. The rubber mixture according to claim 8, characterized in that it contains at least one vulcanization accelerator from the group of sulfur donors consisting of mercaptobenzothiazoles, mercaptosulfenamides, thiocarbamates, thiocarbonates, and dithiophosphates, and dithiodicaprolactams, dithiodimorpholines, and xanthates.

15. The rubber mixture according to claim 8, characterized in that it contains at least one secondary accelerator from the group consisting of 1,6-bis(N,N-dibenzylthiocarbamoyldithio)hexane, TBzTD (tetrabenzylthiuram disulfide), and dithiophosphate.

16. The rubber mixture according to claim 8, characterized in that it has a content of diphenylguanidine and / or substituted diphenylguanidine of up to 0.4 parts by weight based on the total amount of rubber.

17. A method for producing the rubber mixture according to claim 8, comprising the step of mixing at least one rubber with at least one filler and at least one compound of formula (I) according to claim 1, and the step of heating the mixture to a temperature in the range of 60 °C to 200 °C.

18. A method for producing the rubber mixture according to claim 8, comprising the step of 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) together with sulfur at a temperature in the range of 100 °C to 200 °C.

19. A method for producing a vulcanizate by vulcanizing the rubber mixture according to claim 8 at a temperature in the range of 100 °C to 250 °C.

20. Use of the rubber mixture according to claim 8 for producing a vulcanizate.

21. A vulcanizate obtainable by vulcanizing the rubber mixture according to claim 8.

22. A molded article containing one or more vulcanizates according to claim 21.

23. Use of the compound of formula (I) according to any one of claims 1 to 4 for producing the rubber mixture according to claim 5, the vulcanizate according to claim 21, or the molded article according to claim 22.

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