Natural rubber based tire tread composition

Abstract

The invention relates to a rubber composition comprises 100 phr natural rubber with limited amount of carbon black, at least one silica having CTAB SA of higher than 175 m2 / g, and at least one silane or silane-azodicarbonamide mixture, wherein the silane-azodicarbonamide mixture comprises at least one silane, at least one azocarbonyl-functionalized silane and at least one azodicarbonamide compound.

Description

[0001]202400016 Foreign Filing 1 NATURAL RUBBER BASED TIRE TREAD COMPOSITION TECHNICAL FIELD OF THE INVENTION The invention relates to a natural rubber-based tire tread rubber composition, and a vehicle tire including the tread produced using the rubber composition. BACKGROUND OF THE INVENTION In recent years, there has been a growing interest in the use of natural rubber in vehicle tire formulations, especially in vehicle tire formulations together with silica and silane system wherein the silica - silane range has been defined accordingly. It is known in the art that passenger car tires have been formulated by using high amount of polysulfide silanes together with high CTAB surface area silica in a natural rubber-based compound together with synthetic rubbers, but not within the defined range as disclosed in the present invention. An article and presentation from Bob Ohm, Chemtura Corporation Middlebury, CT / Presented at the Fall 168thTechnical Meeting of the Rubber Division, American Chemical Society Pittsburgh, PA November 1- 3, 2005 ISSN: 1547-1977; titled as “THE USE OF A TETRA-ALKYL THIURAM DISULFIDE, WITH AN ACTIVATOR, FOR IMPROVED ROLLING RESISTANCE OF A NR TREAD FORMULATION”, focuses on use of precipitated silica with silane in natural rubber formulations together with TATD and activator for improved rolling resistance wherein the improvement observed by use of TATD accelerator when being used with an activator. Article mentions that higher amounts of silica (60 phr) lead slightly lower abrasion resistance and further higher amount of silane levels (but only from 2.4 to 6.0 phr of S4 polysulfide silane) lead to lower scorch and cure times with higher modulus, tear strength and abrasion resistance, but without mentioning the high CTAB surface area or its effects on the performance improvement. One more article from PPG Industries, Pittsburg Pa. by N.L. Hewitt published in Rubber World Magazine in 1982, an titled as “Compounding with silica for tear strength and low heat build-up”, focuses on rubber formulations being formed by NR with mercapto silane coupling agents and precipitated silica which may reach up to 30 phr, but again without a focus on high CTAB (N-cetyl-N,N,N-trimethylammonium bromide) SA (SA = Surface Area) or silica - silane ratio definition. US 2011 / 0184085 A1 prior art also discloses a rubber formulation comprising NR together with synthetic rubbers, and silane coupling agents (less than 5 parts by mass) together with a silica having CTAB SA of 180 m2 / g or more. The patent application uses at least 15 parts by mass carbon black otherwise the rubber formulation may lead to lower the mechanical strength of tread rubber and lower chunk resistance. A disadvantage of the known silica - silane ratio in the rubber mixtures is the need of using high amount of carbon black to reach out desired rubber performance. The desire in the tire industry is more on the use of natural rubber, with increased silica and / or silane amounts and reduced carbon black in the formulation, while still promising the improved performance but 202400016 Foreign Filing 2 without having high marching modulus. Rubber formulations showing a strong marching modulus are hard to handle in tire production lines, since a constant final quality of the tire may not be achievable with such a compound. It is therefore an object of the present invention to provide a new silica - silane system in the natural rubber mixture to be used mainly in truck tire treads which provides comparable or even improved technical characteristics / performance when compared to known rubber mixtures wherein carbon black or silicas with lower CTAB SA are used as reference material in the natural rubber mixtures. The aim of the present invention is to find the right silica - silane amount ratio in the natural rubber to be formulated especially for the truck tires, that will lead to the same abrasion resistance of carbon black reference compounds when used as a truck tire treads. The present invention relates to the field of sulfur-crosslinkable rubber mixture, and a vehicle tire, especially a truck tire. The sulfur-crosslinkable rubber mixture comprises at least one natural rubber and at least one silica having a CTAB SA of higher than 175 m2 / g, and at least one silane having the general empirical formula (I) or a silane-azodicarbonamide mixture of formulas (I), (II) and (III) as defined in dependent claims, and preferably at least one accelerator. None of the prior art discloses, the rubber tire formulations, comprising the same ratio of silica having CTAB SA of higher than 175 m2 / g together with, relatively to standard compounds, high amount of silane or silane-azodicarbonamide mixture formulated in the natural rubber. Moreover, none of the prior art discloses the use of ultra-accelerator, especially TMTD, in the above- mentioned rubber mixture, that provides a special technical advantage of providing an accelerated system and having no or very low marching modulus or reversion compared to known silica - silane systems being used in rubber formulations. BRIEF SUMMARY OF THE INVENTION Natural Rubber is still one of the most important ingredients for the rubber industry, especially for tire formulations. After thorough investigation, the inventors of the present invention have surprisingly found that the new silica - silane mixture given within specific ratios in the natural rubber to form the rubber mixture, provides the same abrasion resistance of carbon black reference compounds, when used as a truck tire tread. Compounding trials with different silica - silane systems in natural rubber shows very good batch and sheet appearance, very good macro-dispersion and high performance when higher amount of silica is being used together with optimized amounts of silane or silane-azodicarbonamide mixtures. It has been proved with the present invention that, when high amount of silica, having CTAB SA of higher than 175 m2 / g, being used together with, relatively to standard compounds, high amount of silane or silane-azodicarbonamide mixture and formulated in the natural rubber compounding provides comparable reinforcement results, improved stiffness / hysteresis ratio, tensile strength and elongation at break when compared to carbon black reinforced rubber mixtures. 202400016 Foreign Filing 3 Therefore, in a first aspect, the present invention relates to a rubber composition as defined in claim 1; A rubber composition comprising at least one natural rubber (NR), at least one precipitated silica and at least one silane or at least one silane-azodicarbonamide mixture; wherein the silica has a CTAB SA of 175 m2 / g or more, and in an amount of at least at least 40 phr, measured in accordance with ISO 5794-1G standard, the silane or silane-azodicarbonamide mixture is in an amount of between 8 phr < to ≤ 18 phr, the natural rubber in an amount of 100 phr and, carbon black in an amount of 2 phr or less, or no carbon black is used in the rubber composition. The mentioned rubber composition comprises at least one silane of formula (I); (R1)ySi-R2-Sx-R2-Si(R1)y(I) , wherein R1represents C1-C10-alkoxy groups, preferably methoxy or ethoxy groups, phenoxy group or alkylpolyether group –O-(R6-O)r-R7where R6represents a branched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30 hydrocarbon group, preferably -CH2-CH2-, r is an integer from 1 to 30, preferably 3 to 10, and R7represents unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl groups, preferably represents C13H27 alkyl group, y is 1 to 3, preferably 3, and R2represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, preferably C1-C20, particularly preferably C1- C10, very particularly preferably C2-C7-, especially preferably CH2CH2 and CH2CH2CH2, x is the average sulfur chain distribution, wherein x is 1 to 12, preferably 2 to 10, more preferably 2 to 4, OR The mentioned rubber composition comprises at least one silane-azodicarbonamide mixture which comprises at least one silane of formula (I) as defined above, (R1)ySi-R2-Sx-R2-Si(R1)y (I) and at least one azocarbonyl-functionalized silane of formula (II) (R1)3-a(R2*)aSi-R3-NH-C(O)-N=N-R4(II), and and at least one azodicarbonamide compound of formula (III). R5-NH-C(O)-N=N-C(O)-NH-R5(III), wherein R2*represents -OH, C6-C20-aryl groups, C1-C10-alkyl groups, C2-C20-alkenyl group, C7-C20- aralkyl group or halogen, a is 0 to 3, R3represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, R4represents a substituted or unsubstituted aryl or substituted or unsubstituted alkyl group, wherein R5represents a branched or unbranched, saturated or unsaturated, aliphatic or cyclic monovalent C1-C30-hydrocarbon group or a substituted or unsubstituted aryl group. A second aspect of the invention is a method for preparing said rubber mixture. 202400016 Foreign Filing 4 A third aspect of the invention is the use of rubber mixtures for production of tires, especially tire tread and sidewall compounds, cable sheaths, hoses, drive belts, conveyor belts, roller coverings, footwear soles, sealing rings and damping elements. A fourth aspect of the invention is the use of said rubber mixture in a vehicle tire formulation, especially in a truck tire formulation. A fifth aspect of the present invention is a vulcanizate obtained by sulfur vulcanization of the at least one rubber composition as claimed in the present invention. A sixth aspect of the invention is the vehicle tire comprising the at least one vulcanizate in a tread as claimed in the present invention. BRIEF DESCRIPTION OF THE FIGURES For the purpose of better illustrating the advantages and properties of the claimed object of the present invention, one graph is attached as a non-limiting example. Figure 1 is a graph showing the marching modulus change to represent the further effect of using super- accelerator system. The graph illustrates the example with carbon black as a reference example, which do not provide marching modulus during vulcanization, as already explained in the description, and comparative example with inventive examples 4 to 6, wherein super- accelerator system is used. DETAILED DESCRIPTION OF THE INVENTION The rubber composition of the present invention comprises at least one natural rubber, at least one silica having CTAB SA of higher than 175 m2 / g, and at least one silane or at least one silane-azodicarbonamide mixture. Silica - Silane System: According to the present invention, the silica may be any of the types of silica known to those skilled in the art that are suitable as filler for tire rubber mixtures. However, particular preference is given to using a finely divided, precipitated silica which has a CTAB surface area based on ISO 5794-1G standard) of 175 m2 / g or more, preferably in the range from 175 to 250 m2 / g, more preferably from 180 to 240 m2 / g. Such silicas are being used in rubber mixtures for tire treads, to particularly good physical properties of the vulcanizates. Further advantages of using such kind of high CTAB SA silicas in present invention composition is to obtain comparable reinforcement with the carbon black and to obtain very good macro-dispersion in the processing while leading to improved productivity. Another advantage of using high CTAB SA silicas in the present invention is further to improve the tread wear with optimized silane amounts in the rubber mixture and improving wet grip and rolling resistance, with improved tensile strength and elongation at break. Silicas used may thus, for example, be ULTRASIL®9100 GR, ULTRASIL®9500 GR from Evonik Industries AG, which are either commercially available or defined and published in the patent applications from Evonik Industries AG, such as; WO 2004 / 014797 A1 or WO 2004 / 014795 A1. 202400016 Foreign Filing 5 In one embodiment of the present invention, the rubber composition of the invention, comprises at least 40 phr silica, more preferably ≥ 45 phr silica, and most preferably ≥ 50 phr silica. In one preferred embodiment of the present invention the rubber composition of the invention, comprises at least one silica having a phr value of ≥ 50 phr and a CTAB SA value of ≥ 175 m² / g, preferably CTAB SA value of ≥ 180 m² / g, more preferably between 180 m² / g ≤ CTAB SA ≤ 250 m² / g, even more preferably between 180 m² / g ≤ CTAB SA ≤ 240 m² / g Especially use of a comparatively high amount of silica of at least 40 phr, or at least 45 phr preferably at least 50 phr, in combination with the silane which is present in accordance with the invention, particularly advantageous properties arise with regard to the tire properties of the rubber composition and vulcanizates thereof, especially optimized rolling resistance and tensile strength. In one preferred embodiment, the active silica surface (ASS) in the compound is higher than 8500 phr*m² / g; preferably higher than 9000 phr*m² / g wherein the active silica surface in the compound is calculated as; ASS= Silica (phr) * CTAB (m² / g ) in phr*m² / g. The silane content in phr, to be used in the composition mixture, is accordingly calculated relative to the ASS and is expressed as silanization factor (SF) with the formula given below; SF = Silane (phr) *100 / ASS (phr*m² / g ) in g / m² In one embodiment of the present invention, the SF value of the compounding is equal or more than 0,090 g / m², preferably ≥ 0,095 g / m² and more preferably ≥ 0,100 g / m². In one embodiment of the invention the rubber composition comprises carbon black in an amount of less than 10 phr, preferable less than 5 phr and most preferably less than 3 phr. In one embodiment of the present invention, the rubber mixture of the present invention comprises at least one silane in an amount of more than 8 phr, preferably between higher than 8 phr and lower or equal to 18 phr and more preferably between 10 phr ≤ silane amount ≤ 17phr. In one embodiment of the present invention, the rubber composition of the present invention comprises at least one natural rubber, at least one silica having CTAB SA of ≥ 175 m² / g, at least one silane of formula (I), OR at least one silane-azodicarbonamide mixture comprising at least one silane of formula (I), at least one azocarbonyl-functionalized silane of formula (II) , and at least one azodicarbonamide compound of formula (III); wherein the silane has the general empirical formula of (I); (R1)ySi-R2-Sx-R2-Si(R1)y(I) and, 202400016 Foreign Filing 6 R1represents C1-C10-alkoxy groups, preferably methoxy or ethoxy groups, phenoxy group or alkylpolyether group –O-(R6-O)r-R7where R6represents a branched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30 hydrocarbon group, preferably -CH2-CH2-, r is an integer from 1 to 30, preferably 3 to 10, and R7represents unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl groups, preferably represents C13H27 alkyl group, y is 1 to 3, preferably 3, and R2represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, preferably C1-C20, particularly preferably C1- C10, very particularly preferably C2-C7-, especially preferably CH2CH2 and CH2CH2CH2, x is the average sulfur chain distribution, wherein x is 1 to 12, preferably 2 to 10, more preferably 2 to 4, OR at least one silane-azodicarbonamide mixture comprising; at least one silane having the general empirical formula of (I) as described above; (R1)ySi-R2-Sx-R2-Si(R1)y(I) and, at least one azocarbonyl-functionalized silane of formula (II) (R1)3-a(R2*)aSi-R3-NH-C(O)-N=N-R4(II), wherein R2*represents -OH, C6-C20-aryl groups, C1-C10-alkyl groups, C2-C20-alkenyl group, C7-C20- aralkyl group or halogen, a is 0 to 3, R3represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, R4represents a substituted or unsubstituted aryl or substituted or unsubstituted alkyl group, and at least one azodicarbonamide compound of formula (III). R5-NH-C(O)-N=N-C(O)-NH-R5(III), wherein R5represents a branched or unbranched, saturated or unsaturated, aliphatic or cyclic monovalent C1-C30-hydrocarbon group or a substituted or unsubstituted aryl group. In one embodiment of the present invention, the silane-azodicarbonamide mixture comprises 5-95 % by weight of azocarbonyl-functionalized silane of formula II based on the total amount of azocarbonyl- functionalized silane of formula II, silane of formula I and azodicarbonamide of formula III, and 0 – 90 % by weight of silane of formula I based on the total amount of azocarbonyl-functionalized silane of formula II, silane of formula I and azodicarbonamide compound of formula III, and 1 – 80 % by weight of azodicarbonamide compound of formula III based on the total amount of azocarbonyl-functionalized silane of formula II, silane of formula I and azodicarbonamide compound of formula III. In one embodiment of the present invention, the rubber mixture of the present invention comprises at least one silica having CTAB SA of ≥ 175 m² / g in an amount of ≥ 50 phr, in combination with a silane of formula 202400016 Foreign Filing 7 (I) as defined in claim 1, wherein the silane is a di-sulfidic silane, wherein x is between 1.90 – 2.35, preferably between 1.95 – 2.30, most preferably between 2.00 – 2.25. In one embodiment of the present invention, the rubber mixture of the present invention comprises at least one silica having CTAB SA of ≥ 175 m² / g in an amount of ≥ 50 phr, in combination with a silane- azodicarbonamide mixture comprising the silane of formula (I) as defined in claim 1, wherein the silane is a poly-sulfidic-silane, preferably S4 silane, wherein x is between 3.50 – 4.00; preferably 3.55 to 3.85. In one preferred embodiment of the present invention, R1may preferably be; methoxy or ethoxy groups. In one preferred embodiment of the present invention, R2may preferably be (CH2)3. In one preferred embodiment of the present invention, R2*may preferably be; (CH2)3. In one preferred embodiment of the present invention, R3may preferably be; -CH2-, -CH2CH2-, -CH2CH2CH2-, -CH2CH2CH2CH2-, -CH(CH3)-, -CH2CH(CH3)-, -CH(CH3)CH2-, -C(CH3)2-, -CH(C2H5)-, -CH2CH2CH(CH3)-, -CH(CH3)CH2CH2-, -CH2CH(CH3)CH2-, -CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2CH2CH2CH2-, -CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- , -CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- , -CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- , -CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- , -CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2CH2- or . In one preferred embodiment of the present invention, R4may preferably be; phenyl, nitrophenyl or tert- butyl. In one preferred embodiment of the present invention, R5may preferably be; a branched or unbranched alkyl radical. In one preferred embodiment of the present invention, the silane of formula I may preferably be; [(MeO)3Si(CH2)3]2S, [(MeO)3Si(CH2)3]2S2, [(MeO)3Si(CH2)3]2S3, [(MeO)3Si(CH2)3]2S4, [(MeO)3Si(CH2)3]2S5, [(MeO)3Si(CH2)3]2S6, [(MeO)3Si(CH2)3]2S7, [(MeO)3Si(CH2)3]2S8, [(MeO)3Si(CH2)3]2S9, [(MeO)3Si(CH2)3]2S10, [(MeO)3Si(CH2)3]2S11, [(MeO)3Si(CH2)3]2S12, [(EtO)3Si(CH2)3]2S, [(EtO)3Si(CH2)3]2S2, [(EtO)3Si(CH2)3]2S3, [(EtO)3Si(CH2)3]2S4, [(EtO)3Si(CH2)3]2S5, [(EtO)3Si(CH2)3]2S6, [(EtO)3Si(CH2)3]2S7, [(EtO)3Si(CH2)3]2S8, [(EtO)3Si(CH2)3]2S9, [(EtO)3Si(CH2)3]2S10, [(EtO)3Si(CH2)3]2S11, [(EtO)3Si(CH2)3]2S12, 202400016 Foreign Filing 8 [(C3H7O)3Si(CH2)3]2S, [(C3H7O)3Si(CH2)3]2S2, [(C3H7O)3Si(CH2)3]2S3, [(C3H7O)3Si(CH2)3]2S4, [(C3H7O)3Si(CH2)3]2S5, [(C3H7O)3Si(CH2)3]2S6, [(C3H7O)3Si(CH2)3]2S7, [(C3H7O)3Si(CH2)3]2S8, [(C3H7O)3Si(CH2)3]2S9, [(C3H7O)3Si(CH2)3]2S10, [(C3H7O)3Si(CH2)3]2S11, [(C3H7O)3Si(CH2)3]2S12,[(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S, [(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S2, [(EtO)2(C13H27- (OCH2CH2)5O)Si(CH2)3]2S3, [(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S4, [(EtO)2(C13H27- (OCH2CH2)5O)Si(CH2)3]2S5, [(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S6, [(EtO)2(C13H27- (OCH2CH2)5O)Si(CH2)3]2S7, [(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S8, [(EtO)2(C13H27- (OCH2CH2)5O)Si(CH2)3]2S9[(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S10, [(EtO)2(C13H27- (OCH2CH2)5O)Si(CH2)3]2S11[(EtO)2(C13H27-(OCH2CH2)5O)Si(CH2)3]2S12, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]]2S2, [(EtO)(C13H27- (OCH2CH2)5O)2Si(CH2)3]2S3, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S4, [(EtO)(C13H27- (OCH2CH2)5O)2Si(CH2)3]2S5, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S6, [(EtO)(C13H27- (OCH2CH2)5O)2Si(CH2)3]2S7, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S8, [(EtO)(C13H27- (OCH2CH2)5O)2Si(CH2)3]2S9, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S10, [(EtO)(C13H27- (OCH2CH2)5O)2Si(CH2)3]2S11, [(EtO)(C13H27-(OCH2CH2)5O)2Si(CH2)3]2S12, and may particularly preferably be [(EtO)3Si(CH2)3]2S, [(EtO)3Si(CH2)3]2S2, [(EtO)3Si(CH2)3]2S3, [(EtO)3Si(CH2)3]2S4, [(EtO)3Si(CH2)3]2S5, [(EtO)3Si(CH2)3]2S6, [(EtO)3Si(CH2)3]2S7, [(EtO)3Si(CH2)3]2S8, [(EtO)3Si(CH2)3]2S9, [(EtO)3Si(CH2)3]2S10, [(EtO)3Si(CH2)3]2S11, [(EtO)3Si(CH2)3]2S12. In one preferred embodiment of the present invention, azocarbonyl-functionalized silane of formula (II) selected from; (CH3CH2O-)3Si-CH2-NH-CO-N=N-phenyl, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-phenyl, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-phenyl, (CH3O-)3Si-CH2-NH-CO-N=N-phenyl, (CH3O-)3Si-(CH2)2-NH-CO-N=N-phenyl, (CH3O-)3Si-(CH2)3-NH-CO-N=N-phenyl, (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-CH2-NH-CO-N=N-phenyl, (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-(CH2)2-NH-CO-N=N-phenyl, (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-(CH2)3-NH-CO-N=N-phenyl, (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-CH2-NH-CO-N=N-phenyl, (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-(CH2)2-NH-CO-N=N-phenyl, (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-(CH2)3-NH-CO-N=N-phenyl, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-(p-nitrophenyl), (CH3O-)3Si-CH2-NH-CO-N=N-(p-nitrophenyl), (CH3O-)3Si-(CH2)2-NH-CO-N=N-(p-nitrophenyl), 202400016 Foreign Filing 9 (CH3O-)3Si-(CH2)3-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-CH2-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-(CH2)2-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)2Si(-O(CH2-CH2-O)5-C13H27)-(CH2)3-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-CH2-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-(CH2)2-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)Si(-O(CH2-CH2-O)5-C13H27)2-(CH2)3-NH-CO-N=N-(p-nitrophenyl), (CH3CH2O-)3Si-CH2-NH-CO-N=N-CH3, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-CH3, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-CH3, (CH3O-)3Si-CH2-NH-CO-N=N-CH3, (CH3O-)3Si-(CH2)2-NH-CO-N=N-CH3, (CH3O-)3Si-(CH2)3-NH-CO-N=N-CH3, (CH3CH2O-)3Si-CH2-NH-CO-N=N-CH2CH3, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-CH2CH3, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-CH2CH3, (CH3O-)3Si-CH2-NH-CO-N=N-CH2CH3, (CH3O-)3Si-(CH2)2-NH-CO-N=N-CH2CH3, (CH3O-)3Si-(CH2)3-NH-CO-N=N-CH2CH3, (CH3CH2O-)3Si-CH2-NH-CO-N=N-CH2CH2CH3, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-CH2CH2CH3, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-CH2CH2CH3, (CH3O-)3Si-CH2-NH-CO-N=N-CH2CH2CH3, (CH3O-)3Si-(CH2)2-NH-CO-N=N-CH2CH2CH3, (CH3O-)3Si-(CH2)3-NH-CO-N=N-CH2CH2CH3, (CH3CH2O-)3Si-CH2-NH-CO-N=N-CH2CH2CH2CH3, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-CH2CH2CH2CH3, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-CH2CH2CH2CH3, (CH3O-)3Si-CH2-NH-CO-N=N-CH2CH2CH2CH3, (CH3O-)3Si-(CH2)2-NH-CO-N=N-CH2CH2CH2CH3, (CH3O-)3Si-(CH2)3-NH-CO-N=N-CH2CH2CH2CH3, (CH3CH2O-)3Si-CH2-NH-CO-N=N-C(CH3)3, (CH3CH2O-)3Si-(CH2)2-NH-CO-N=N-C(CH3)3, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-C(CH3)3, (CH3O-)3Si-CH2-NH-CO-N=N-C(CH3)3, 202400016 Foreign Filing 10 (CH3O-)3Si-(CH2)2-NH-CO-N=N-C(CH3)3 or (CH3O-)3Si-(CH2)3-NH-CO-N=N-C(CH3)3 , and particularly preferably (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-phenyl, (CH3O-)3Si-(CH2)3-NH-CO-N=N-phenyl, (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-(p-nitrophenyl). In one preferred embodiment of the present invention, azodicarbonamide compound of formula (III) selected from; CH3-(CH2)3-NH-C(=O)-N=N-C(=O)-NH-(CH2)3-CH3CH3-(CH2)4-NH-C(=O)-N=N-C(=O)-NH-(CH2)4-CH3 CH3-(CH2)5-NH-C(=O)-N=N-C(=O)-NH-(CH2)5-CH3 CH3-(CH2)6-NH-C(=O)-N=N-C(=O)-NH-(CH2)6-CH3 CH3-(CH2)7-NH-C(=O)-N=N-C(=O)-NH-(CH2)7-CH3 CH3-(CH2)8-NH-C(=O)-N=N-C(=O)-NH-(CH2)8-CH3 CH3-(CH2)9-NH-C(=O)-N=N-C(=O)-NH-(CH2)9-CH3 CH3-(CH2)10-NH-C(=O)-N=N-C(=O)-NH-(CH2)10-CH3 CH3-(CH2)11- NH-C(=O)-N=N-C(=O)-NH-(CH2)11-CH3 (H3C)2CH-NH-C(=O)-N=N-C(=O)-NH-CH(CH3)2 (H3C)2CH -CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(CH3)2 (H3C)3C-NH-C(=O)-N=N-C(=O)-NH-C(CH3)3 (H3C)3C-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-C(CH3)3 (H3C)2CH-(CH2)2-NH-C(=O)-N=N-C(=O)-NH-(CH2)2-CH(CH3)2 H3C-CH2-(H3C)CH-CH2,-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(CH3)-CH2-CH3, (H3C-H2C)2CH-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(CH2CH3)2 H3C-(CH2)3-(H5C2)CH-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(C2H5)-(CH2)3-CH3 H3C–(CH2)3-(H7C3)CH-CH2-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH2-CH(C3H7)–(CH2)3 -CH3 H5C6-NH-C(=O)-N=N-C(=O)-NH-C6H5 and particularly preferably be CH3(CH2)6-NH-C(=O)-N=N-C(=O)-NH- (CH2)5-CH3 CH3(CH2)7-NH-C(=O)-N=N-C(=O)-NH- (CH2)7-CH3 CH3(CH2)3-CH(C2H5)-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(C2H5)-(CH2)3-CH3 CH3 –(CH2)3-CH(C3H7)-CH2-CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH2-CH(C3H7)–(CH2)3 -CH3. According to a preferred embodiment of the invention, the rubber mixture is a sulfur-crosslinkable rubber mixture and for that purpose comprises at least one diene rubber. Diene rubbers are rubbers which are formed by polymerization or copolymerization of dienes and / or cycloalkenes and thus have C═C double bonds either in the main chain or in the side groups. The diene rubber here is preferably selected from the group consisting of natural polyisoprene and / or synthetic polyisoprene and / or epoxidized polyisoprene and / or butadiene rubber and / or butadiene- 202400016 Foreign Filing 11 isoprene rubber and / or solution-polymerized styrene-butadiene rubber and / or emulsion-polymerized styrene-butadiene rubber and / or styrene-isoprene rubber and / or liquid rubbers having a molecular weight Mw of greater than 20000 g / mol and / or halobutyl rubber and / or polynorbornene and / or isoprene- isobutylene copolymer and / or ethylene-propylene-diene rubber and / or nitrile rubber and / or chloroprene rubber and / or acrylate rubber and / or fluoro rubber and / or silicone rubber and / or polysulfide rubber and / or epichlorohydrin rubber and / or styrene-isoprene-butadiene terpolymer and / or hydrogenated acrylonitrile- butadiene rubber and / or hydrogenated styrene-butadiene rubber. Nitrile rubber, hydrogenated acrylonitrile-butadiene rubber, chloroprene rubber, butyl rubber, halobutyl rubber or ethylene-propylene-diene rubber in particular are used in the production of industrial rubber articles, such as belts, drive belts and hoses, and / or footwear soles. The mixture compositions known to those skilled in the art for these rubbers, which are specific in terms of fillers, plasticizers, vulcanization systems and additives, are preferably employed. According to the present invention, the natural rubber may preferably be a diene rubber. Natural Rubber: According to the present invention, natural rubber is used as the main component of the rubber composition, preferably in amounts up to 100 phr. In a particularly advantageous embodiment of the invention, the rubber mixture comprises at least one natural rubber obtained from different countries / sources such as; SIR (Indonesia), SMR (Malaysia), SVR (Vietnam), STR (Thailand), or combinations thereof. Natural rubbers generally named with the country of origin such as SMR: Standard Malaysia Rubber. There are several different grades of natural rubber such as; SIR 3CV50, SIR 3CV60, SIR 3L, SIR 3WF, SIR 5, SIR 10, SIR 10VK, SIR 20 SIR, 20VK, SMR 5, SMR 10, SMR 20, SMR GP, SMR CV 50, SMR CV60, deproteinized natural rubber e.g. P10, epoxidized NR, SMR L, SMR 10 CV, SMR 20 CV TSR 20, TSR 10, TSR 5, TSR L, TSR CV. Natural rubber maybe also obtained from different origins, not only from trees, like the Hevea brasiliensis, but also from other natural sources of latex producing plants like the dandelion, especially the Russian dandelion or spurge (Manihot glaziovii, Maniok), Ficus elastica or Taraxacum bicorne. The NR products should meet international standards, i.e. SIR 20 and SMR 20 must meet the same technical requirements. Rubber Mixtures: In a preferred embodiment of the invention, rubber formulation comprises only one natural rubber (100 phr) or mixtures of more than one natural rubber without having any synthetic rubber formulated in the rubber composition. In a particular embodiment of the invention, the rubber mixture comprises a polymer blend of two or more of the natural rubbers with the sum of all the natural rubbers present adding up to 100 phr. 202400016 Foreign Filing 12 The natural rubber may be an epoxidized natural rubber or a deproteinized natural rubber or a natural otherwise functionalized rubber, where the functional groups may be amine and / or amide and / or urethane and / or urea and / or aminosiloxane and / or siloxane and / or silyl and / or alkylsilyl, for example N,N- bis(trimethylsilyl)aminopropylmethyldiethoxysilane or methyltriphenoxysilane, and / or halogenated silyl and / or silane sulfide and / or thiol and / or hydroxyl and / or ethoxy and / or epoxy and / or carboxyl and / or tin, for example tin tetrachloride or dibutyldichlorotin, and / or silanol and / or hexachlorodisiloxane and / or thiocarboxy and / or nitrile and / or nitroxide and / or amido and / or imino and / or urethane and / or urea and / or dimethylimidazolidinone and / or 2-methyl-2-thiazoline and / or 2-benzothiazoleacetonitrile and / or 2- thiophenecarbonitrile and / or 2-(N-methyl-N-3-trimethoxysilylpropyl)thiazoline and / or carbodiimide and / or N-substituted aminoaldehyde and / or N-substituted aminoketone and / or N-substituted aminothioaldehyde and / or N-substituted aminothioketone and / or benzophenone and / or thiobenzophenone with amino group and / or isocyanate and / or isothiocyanate and / or hydrazine and / or sulfonyl and / or sulfinyl and / or oxazoline and / or ester groups. The rubber composition is suitable in particular for tires, especially truck tires and may in principle be used in any component, such as in particular the tread, the sidewall, the flange profile, and also in other so-called body components, wherever the amount of natural rubber reaches 100 % of total rubber used in rubber composition. Also in mechanical rubber goods like belts or shoe soles based on natural rubber the rubber composition makes sense to use. Especially if no carbon black is used it is possible to manufacture colored rubber articles without compromises in performance. Particularly good processibility of the rubber mixture of the invention and optimized tensile properties are achieved in this way of comprising high amount of high CTAB SA silica, well balanced with the ratio of silane in a natural rubber, with particularly limited amount of carbon black, or no carbon black. Particularly good abrasion and tensile properties of the rubber mixture of the invention and good processibility coupled with low hysteresis loss and good abrasion and tensile properties, are achieved in this way as well. Sulfur-Accelerator & Retarder System: One of the other important aim of the present invention is to reduce that marching modulus, preferably nearly to zero. In one preferred embodiment of the invention, the rubber mixture further comprises an accelerator. When a standard vulcanization system known in the art is used, sulfur (S) and / or accelerator (ACC) materials (S- ACC) and this tends to a so-called marching modulus, it requires an addition of high amount of carbon black or the use of a secondary accelerator, such as DPG. For the purpose of reducing marching modulus, in one embodiment of the present invention, the rubber mixture further comprises at least one accelerator, added in the final stage of mixing (3rdstage) together with the sulfur to form Sulfur-Accelerator system (as shown in Table 2, and 2.1), wherein the accelerator (ACC) is selected from sulfenamides, dithiocarbamates, preferably from tetra-alkyl thiuram disulfide (TATD), most preferably tetra-methyl thiuram disulfide (TMTD), or mixtures thereof. In one preferred embodiment, rubber composition comprises an accelerator (ACC) in an amount of ≥ 202400016 Foreign Filing 13 0,50 phr, more preferable ≥ 0,60 phr and most preferable ≥ 0,75 phr, but not exceeding 3 phr, and preferably the accelerator is TMTD. In one embodiment of the invention, in case the incubation time is short during final stage while using TMTD accelerator, a retarder may be used as a further ingredient. The retarder may be; N-Phenyl-N- (trichlormethylsulfenyl)-benzolsulfonamid or N-(Cyclohexylthio) phthalimide (CTP or PVI), preferably PVI is used. Further ingredients could be anti-reversion agents such as WK-901 (1,3- bis(citraconimidomethyl)benzene). In one preferred embodiment of the invention, rubber mixture comprises a retarder in an amount between 0.1 < retarder < 0.5 phr, and preferably the retarder is PVI and in an amount 0.1 < PVI < 0.5 phr; preferably 0.2 phr < PVI < 0.4 phr. In one embodiment of the invention the rubber composition comprises sulfur in an amount of more than 1.0 phr, or more than 0.8 phr when sulfur is used in combination with CBS activator, or in case of a polysulfidic silane is being used in the rubber mixture, the amount of sulfur added to the compound should not lower than 1 phr and not higher than 3 phr. In one embodiment of the invention the rubber composition comprises sulfur in an amount of 1.2 phr ≤ sulfur ≤ 2.5 phr (soluble or insoluble). The rubber composition according to the invention may contain at least one filler. The terms “silicate” and “silica” are used synonymously in the context of the present invention. The rubber composition of the present invention may also comprise at least one carbon black, especially an industrial carbon black in an amount of less than 5 phr, more preferably 2 phr or less. One preferred embodiment of the present invention comprises no carbon black within the rubber formulation. Possible carbon blacks are all types of carbon black known to a person familiar with the technical field. Fillers usable for the rubber mixtures according to the invention include the following fillers: - Carbon blacks: The carbon blacks may be produced by the lamp-black process, furnace-black process, gas-black process or thermal process and have BET surface areas of from 20 to 200 m2 / g. The carbon blacks may optionally also contain heteroatoms, such as Si for example. The carbon black maybe also obtained from recycling, or upcycling processes. - Amorphous silicas produced for example by precipitation from solutions of silicates or flame- hydrolysis of silicon halides with specific surface areas of from 5 to 1000 m2 / g, preferably from 20 to 400 m2 / g (BET surface area) and with primary particle sizes of from 5 to 400 nm. The silicas may optionally also be in the form of mixed oxides with other metal oxides, such as oxides of Al, Mg, Ca, Ba, Zn and titanium. - Amorphous silicas produced for example by precipitation from solutions of silicates or flame- hydrolysis of silicon halides with specific surface areas of from 5 to 1000 m2 / g, preferably from 20 to 400 m2 / g (BET surface area) and with primary particle sizes of from 5 to 400 nm and doped 202400016 Foreign Filing 14 during the production chain or containing either Al or Mg or Ca or Ba or Zn or titanium in amounts higher than 1000 ppm. - Synthetic silicates such as aluminium silicate, alkaline earth metal silicates such as magnesium silicate or calcium silicate, with BET surface areas of from 20 to 400 m2 / g and primary particle diameters of from 5 to 400 nm. - Synthetic or natural aluminium oxides and synthetic or natural aluminium hydroxides. - Natural silicates, such as kaolin and other naturally occurring silicas. - Glass fibres and glass-fibre products (mats, strands) or glass microbeads. It is possible with preference to use amorphous silicas prepared by precipitation from solutions of silicates, with BET surface areas of 20 to 400 m2 / g, more preferably 100 m² / g to 250 m² / g, in amounts of 5 to 150 parts by weight, based in each case on 100 parts of rubber. With very particular preference, it is possible to use precipitated silicas as filler. The fillers mentioned may be used alone or in a mixture. The rubber compositions according to the invention may contain 5 to 150 parts by weight of filler and 0.1 to 30 parts by weight, preferably 2 to 25 parts by weight, particularly preferably 5 to 20 parts by weight, of the silane-azodicarbonamide mixture according to the invention, wherein the parts by weight are based on 100 parts by weight of rubber (phr). The silane-azodicarbonamide mixture according to the invention may be used as adhesion promoters between inorganic materials, for example glass beads, glass shards, glass surfaces, glass fibres, or oxidic fillers, preferably silicas such as precipitated silicas and formed silicas, and organic polymers, for example thermosets, thermoplastics or elastomers, or as crosslinking agents and surface modifiers for oxidic surfaces. The rubber compositions according to the invention may comprise further rubber auxiliaries, such as further reaction accelerators, ageing stabilizers, heat stabilizers, light stabilizers, antiozonants, processing aids, plasticizers, resins, tackifiers, blowing agents, dyes, pigments, waxes, extenders, organic acids, retarders, metal oxides, and activators such as diphenylguanidine, triethanolamine, polyethylene glycol, alkoxy-terminated polyethylene glycol alkyl-O-(CH2-CH2-O)yI-H with yI= 2-25, preferably yI= 2-15, more preferably yI= 3-10, most preferably yI= 3-6, or hexanetriol, that are familiar to the rubber industry. The rubber auxiliaries may be used in familiar amounts determined inter alia by factors including the intended use. Customary amounts may, for example, be amounts of 0.1 to 15 phr based on rubber. Crosslinkers used may be peroxides, sulfur or sulfur donor substances. The rubber mixtures according to the invention may further comprise vulcanization accelerators. Examples of suitable vulcanization accelerators may be mercaptobenzothiazoles, sulfenamides, thiurams, dithiocarbamates, thioureas and thiocarbonates. Another aspect of the present invention is a process for preparing rubber composition of claim 1, which comprises the following steps; Preparing rubber mixture: The mixing is carried out in a two- or a three-stage mixing protocol. 202400016 Foreign Filing 15 Within the first stage the polymer and the reinforcing filler systems are mixed for maximum of 5 min at a maximum batch temperature of 160 °C, to ensure a good hydrophobation of the silica by the bi-functional silane, in case a silica - silane system is used. The second stage is an optional up to 5 min re-mill step, if necessary further ingredients may be added in this step. It is also carried out at a batch temperature of below 160 °C. The addition of the reinforcing filler systems may also be done as partly adding it, e.g., one part of the filler in the 1stand the rest of the filler in the 2ndmixing step. The same can be done with the silane in case of silica and silane are used. The accelerator systems are added in a separate final stage, mixed at batch temperatures below 120 °C for at least 2 min. Optionally the final stage can also be done on an open mill, which is already a known step in the art. Sometimes and due to special equipment more stages maybe applied using e.g., internal mixers, tandem mixers, extruders or open mills. The rubber compositions according to the invention can be vulcanized at temperatures of 100°C to 200°C, preferably 130°C to 180°C, optionally at a pressure of 10 to 200 bar. The blending of the rubbers with the silica filler and the silane or silane-azodicarbonamide mixtures may be carried out in known mixing units, such as rollers, internal mixers, either as tangential or intermeshing, tandem mixers and mixing extruders. The rubber compositions according to the invention can be used for production of moulded articles, for example for the production of tires, especially pneumatic tires or tire treads or tire sidewalls, cable sheaths, hoses, drive belts, conveyor belts, roller coverings, footwear soles, sealing rings and damping elements. Main advantage of the present invention is to provide improved tensile strength and rolling resistance when silica - silane system is performed in natural rubber. Moreover, the treadwear is improved by using high amount of high CTAB SA silica together with optimized silane amounts. Advantages of the silica - silane ratios being used in the natural rubber according to the present invention are improved reinforcement compared to carbon black, improved stiffness - hysteresis ratio, very good batch and sheet appearances and very good macro-dispersion. Advantages of the silica - silane ratios being used in the natural rubber together with accelerator according to the present invention are improved marching modulus by having nearly zero marching modulus. The rubber mixture according to the invention can be used as vehicle tire rubber mixture, especially truck tire rubber mixture. Method of Measurements For CTAB SA determination of silicas, known standards in the art has been followed as already disclosed in WO 2023072666 A1 application from Evonik Operations GmbH, and as also given below. CTAB surface area determination in accordance with ISO 5794-1G 202400016 Foreign Filing 16 The method is based on the adsorption of buffered CTAB (N-cetyl-N,N,N-trimethylammonium bromide) in aqueous solution on the "outer" surface of silicas, which is also referred to as " active surface". Unadsorbed CTAB is back-titrated by means of NDSS (dioctylsodium sulfosuccinate solution). The endpoint of the titration is at the maximum rise in opacity of the solution. Active silica surface (ASS) in the rubber compound is calculated as: ASS (phr*m2 / g)= Silica in phr * CTAB in m² / g. Silanization factor (SF) in the rubber compound is calculated as: SF (g / m2)= Silane in phr *100 / ASS in phr*m2 / g Marching Modulus The marching modulus is defined as difference of the torque values in dNm measured after 20 min and 15 min testing time. The values are obtained by the Moving Die Rheometer (MDR), according to DIN 53529, ISO 6502, at 150°C and 0,5° deflection. Tensile test The tensile test is performed according to DIN 53504, ISO 37 on dumbbells S1. DIN abrasion The DIN abrasion is tested according to DIN ISO 4649 as volume loss in mm³ at a force of 10 N. EXPERIMENTAL PART The invention is further illustrated in detail hereinafter with reference to examples and comparative examples, without any intention to limit the scope of the present invention. EXAMPLES Silane Substances used Si 266™ (bis-[3-(triethoxysilyl)-propyl]-disulfide), S2-silane, is used in some of the inventive examples provided in Table 2. It is a commercially available silane from Evonik Operations GmbH, or other Evonik entities. Si 299™ is a silane-azodicarbonamide mixture; which is a mixture of Si 69™ (bis-[3-(triethoxysilyl)- propyl]-tetrasulfide)- S4 silane from Evonik Operations GmbH or other Evonik entities, azocarbonyl- functionalized silane and azodicarbonamide compound. The mixture of this compound is used for some of the inventive examples provided in Table 2. Above mentioned Si 299™ silane-azodicarbonamide mixture is disclosed in one of the international patent applications from Evonik Operations GmbH, published with the publication number of WO / 2023 / 066688 A1. Silica Substances used 202400016 Foreign Filing 17 ULTRASIL®7000 GR (silica with CTAB SA 160 m² / g) – Hereby this silica and / or other corresponding silicas having lower than CTAB SA 175 m² / g may be named as low SA silica. ULTRASIL®7800 GR (silica with CTAB SA 180 m² / g) - Hereby this silica and / or other corresponding silicas having equal or higher than CTAB SA 175 m² / g may be named as high SA silica. ULTRASIL®9100 GR (silica with CTAB SA 200 m² / g) – Hereby this silica and / or other corresponding silicas having equal or higher than CTAB SA 175 m² / g may be named as high SA silica. All above mentioned ULTRASIL silica grades are commercially available from Evonik Operations GmbH, or other Evonik entities. Silica with CTAB SA of ≥ 240 m2 / g, as being disclosed in WO 2023072666 A1 patent application from Evonik Operations GmbH, specifically Example 4 of the application is used in the examples provided in Table 2. Other examples 1 to 7 disclosed in the same patent application, WO 2023072666 A1, having CTAB SA of ≥ 200 m2 / g may also be used as an alternative inventive silica in the rubber compositions of the present invention. Table 1: List of Materials used in Examples Material Source 1ststage SMR 10 / Natural Rubber SMR 10, Wurfbain Nordmann GmbH masticated to 60-70 Mooney units (ML(1+4) at 100°C) by Harburg- Freudenberger Maschinenbau GmbH Silica Evonik Operations GmbH ULTRASIL®7000 GR ULTRASIL®9100 GR ULTRASIL®7800 GR Example 4 of WO 2023072666 A1 Silane Evonik Operations GmbH Si 266 Si 299 N234 / Carbon Black Orion Engineered Carbons GmbH ZnO RS RAL 844 C Rotsiegel zinc oxide, Grillo Zinkoxid GmbH Stearic acid- Endenor ST 1 GS Edenor ST1, Caldic Deutschland GmbH TMQ Vulkanox®HS / LG, Rhein-Chemie GmbH 6-PPD Vulkanox®4020 / LG, Rhein-Chemie GmbH Wax Protektor G 3108, Paramelt B.V. 2ndstage Batch 1ststage 3rdstage Batch 2ndstage CBS Vulkacit®CZ / EG-C, Rhein-Chemie GmbH Rubber makers sulfur Ground sulfur, Azelis S.A. Rhenogran DPG-80; 80 % DPG Lanxess Distribution GmbH TMTD- Ultra-Accelerator Lanxess Distribution GmbH PVI- Retarder Weber & Schaer.y pbm 7.0 0 0 0 0.0.00.00 0storx C E 07 030. .5 55 210.30.3apsnae.p 0m 60.rm 0 0 0 0 o.00.0.0h x 00.5 20.0.pC E 1 5 5 1 3 3itnueh.T p 0 0 0 0.m 5lyo.x0.0.0 C 0 00.0.50.0 0 20.0.e E 7 3 5 5 1 3 3vitceps.e pr4 0 0 0 0 0 m.0 00 01.o x. .02E 7 3.0.0.05 5 1.0C 0 0 5 2 3.3lebaT.dn p 0 0 0 0am 32o. .0 x 0 C E 010.0.0.0 0 5 55 210.30.3elbaTni.p d 0 0 0 0iem 2.0.0.0.0.0 0ifo x 0 0 5 20.0.c C E 7 3 5 1 3 3epssi.s pn 0 0iom 1.0 0 00 00 0ito x. . .0.C E 07 0 5 20.0.s 3 5 1 3 3o p molcrs o 0 e nrt00 bboin. .00utio x 0.0 0 50.0.s C E 1 5 3 3re o v pitn m e.o v d C niesreti r r r r r r r r rd u b n u hp h p h p h p h p h p h p h hnrb p pae e b u)v bRitu UarrevitMa waa0 prr7m e a -o p 0c htfm6e o:)htorstrC 4 f + ofa po1(n L)d 0 4 R R e o s 0i M3)u 1te y 2G Ge nalg en N 0 0 n n u oito admto(0 0al o k 0 1ic7 9arle osg Mla SLILI2idu s Fn ( BS S S c amrb: i0 n A A( acoft2 xi1R o 6ih R BbR R 6raeig elbtm s MS- Rra TL TL 2iOneth e a T w T 1 S E B C U U S Z S 5 0 0 0 0 08.83.0 0 0 0 0 0.10.10.3 1 71 710.20.15.28.03.0 0 0 0 0 08.83.3 0 0 0 0 0 0.01.01.01 71 71.02.51.82.30.0 0 0 0 0 00.0. 6.6 0 0 0 0 10.10.1 71 710.20.15.2 0 0 0 0 00.06.0 0 0 0.01.01.1 7 6 1 701.02.51.2 0 0 0 0 00.06.6 0 0 0 0.10.10.1 71 710.20.15.2 0 0 0 0 00.0.. .6.0 0 0 00 0601.0 51 1 1 71 7 2.1.2 0 0 0 0 00.0.0 0 0 0.10.10.6 1 7 6 1 710.20.15.2 0 0 0 0 00.40.4 0 0 0.10.10.1 61 614.16.1 0 91 r hrhrhrhrhrhrhr r rp p p p p p p h p h p h p eg e a g tastgnil gsi ingFixinixngie mtemerg ats g dn)1 a 2rostot)rFg msm av e61n0iorfgonrf itGdr0 Dxieic P ri rax erAt(De0utuu Dr(4 Q P xa dm mt lfS%TI2 MP- nix dr ixu B M V0 T 6 W 2 M 3 0 2 M S C 8 T P 5 7.x E 0 .0.0 v 00.0.0 0 0 0 nI001 55 21.03.03.01.1 6.x E 0 .0.v 0 0 0 0 0 0 nI00 0.5.0 0 1.02 55 61.03.03.01.1 5.x E 0 .0.0 v 0 0 0 0 0 nI010.0.0.0 2 55 210.30.30.10.1 4.x E 0 .0.0 0 v 00.0.0 0 0 0 nI01 55 001.03.03.01.1 3.x E 0 .0.0 0 v 00.0.0 0 0 0 nI01 55 010.30.30.10.1 2.x E 0 .0.0 0 v 00.0.0 0 0 0 nI01 55 410.30.30.10.1 1.x E 0 .0.0 0 v 00.0.0 0 0 0 nI01 55 210.0.0.0.s 3 3 1 1 n oitis o 0 p 2 mtio nrhrhrhrhr r r r r r ru p p p p h p h p h p h p h p h h C p p r e b b u)R U eMvi0 t71 n- Ae v 0 66 nI66 f:)4 2 gno+ 7i1 03 l)in()2eFoitL 4 R R 0rna M32)utgi lu e y 2G GeerN 0 0 O eixnomg ratno(0 0 WalimeFoso k 1 8 c9 7foSn6 Fi:g Md(la LILI42alic1 01.ni0BS S S S nle ( ( a002 xi1o A A p 4elm RbrR R 6 9 cirD T T ma 62 92 a Q P2 bts M a L L xi iOnetMP0 a -2 T 1 S C U U E S S Z S T 6 5 202400016 Foreign Filing 22 Mixture production is described in table 3. The elastomer mixtures were produced with a GK 1.5 E internal mixer from Harburg Freudenberger Maschinenbau GmbH. Test methods used for the mixtures and vulcanizates thereof were effected according to table 7. The vulcanizates were produced in a vulcanizing press at 150°C with a vulcanization time shown in table 5. Table 3: Mixture of Production of a Natural Rubber Mixture 1ststage GK 1.5 E, kneader fill factor 0.65; 65 rpm; kneader temperature: 65°C min:sec Desired mixing temperature: 140-150°C 00:00 – 00:30 Add polymer; close ram and mix for 30 s 00:30 – 01:30 Add 1 / 2 of silica, silane / silanes; close ram and mix for 60 s 01:30 – 01:30 Lift ram to vent, clean ram 01:30 – 02:30 Add 1 / 2 of silica, remaining constituents from the first stage; close ram and mix for 60 s 02:30 – 02:30 Lift ram to vent, clean ram 02:30 – 04:00 Close ram and mix for 90 s; maintain temperature at 140°C – 150°C optionally by varying mixer speed 04:00 – 04:00 Lift ram to vent 04:00 – 05:00 Close ram and mix for 60 s; maintain temperature at 140°C – 150°C optionally by varying mixer speed 5:00 Discharge mixture and check weight Form a milled sheet on a laboratory roller mill (2 roller calendars) for 45 s at a roller gap of 4 mm and finally discharge said sheet Storage: 24 h / RT 2ndstage GK 1.5 E, kneader fill factor 0.62; 80 rpm; kneader temperature: 80°C Desired mixing temperature: 140-150°C 00:00 – 01:00 Add mixture from 1ststage; close ram and mix for 60 s 01:00 – 03:00 Mix for further 120 s, maintain temperature at 140°C – 150°C optionally by varying mixer speed 3:00 Discharge mixture and check weight Form a milled sheet on a laboratory roller mill (2 roller calendars) for 45 s at a roller gap of 4 mm and finally discharge said sheet Storage: 4 - 24 h / RT 3rdstage GK 1.5 E, kneader fill factor 0.59; 55 rpm; kneader temperature: 50°C Desired mixing temperature: 90-110°C 00:00 – 02:00 Add mixture from 2ndstage; accelerator, sulfur; close ram and mix for 120 s 02:00 Discharge mixture and form a milled sheet on a laboratory roller mill (2 roller calendars) for 20 s at a roller gap of 3 – 4 mm Storage: 12 h / RT 7 0 . v.0 1 x 060 011. .1.2.4 nIE 2 1 0 52 42 22 9 55 . 4 v.0 00 02E 1 91.9.6.3 nIx 8 9.0 02 92 22 41 44 0 . 3 v.0 9 x 020 010.5.8.5.6 nIE 2 1 0 2 92 42 31 94 0 . v2.0 02 1 13.0.5.4 nIx E 42 31.0 52 03 62 41 94 0 . 1 v.0 1 x 00 011.57.4.2.3 nIE 2 1 0 2 92 62 41 15 p 7 m.0 0 1 o x C E 0 . 0 0 2 111.4.0 52 45.1 13.1 1 6 1 82 p 6 m.0 4 o x 0 01.5.0 2 00.5.8 C E.61 88 5 2 02 11 64 p 5 m.o x 0 0 48.1.3.3 C E.6 0 1 881.0 52 91 71 01 54 p 4 m.0 4 o x 0 01.2.00.0.9 C E.61 88 0 52 2 51 31 33tp 3.0 n m e o x 4 E 0 01.4.20.11.0 03m C.61 88 0 52 2 2 1 5evorp2 0 p m.ox 0 00 1 1.2.36.72.1m CE.02 11 5 2I0 2 2 1 8 5ec n p 1 m.0 a 0 1mro x E 0 0 . 0 11.50.29.74.0 74o C 2 1 0 2 2 1 1 4frePortg n.nio x5 0C El - - -5.2 3.32 9.36w 1 8 5o hS2 / sttig / m*²a a as n 2rm / inP P Pe T U m h p g g m M M M %lacis) )y C)h°C°CP 3 0°fe 2(6(0 k 6 ao mihtht( erstltn g g n%btus o n 0 i e e 0aetrR A atrt3n o:S zis ssit5n e B alieliula)elA Scls s u g n n d nCb T S F u e e oo°l0a6T C A S V T T M E(5.x E.v 6 nI70.1 97 . x E.v 9 nI46.0 -.x E.v 3 nI15.0 -.p m 7 0 o.x C E2.1 46 . p m 6.2 o x C E8.1 19 . p m 5.2 o x C E7.1 -) .m p arm 4 9 g aio.x C E7.9 d 2 9 1.ig.F p o m 3.9 slo x a C E9.1 59 ee S(e.g p n m 2 5 a o.x h C E1.C 2 - s 5ul2 u.d p o m 1.6 M o x C E2.10 g 2 1 nih cralM o nrto n r o.3 x C7.14 otE 0 1 are 3)lg ec mnilic m af(Fn o sgi tulNu 0ec 1re d,offF eo n Moi6 e s1 h g0 Tniar0:6 h b0cra42elb aNI0 a 2 T M D 5 202400016 Foreign Filing 26 RESULTS AND CONCLUSION Test results can be evaluated based on improvements in performance and processability. Table 5 reflects mainly abrasion resistance relevant laboratory parameters showing the improvements in performance. Table 6 and Figure 1 reflect mainly Marching Modulus related data as a proof of improved processability. In order to obtain the best wear performance (means abrasion resistance of real truck tire treads) a high tensile strength measured at low and high temperatures is needed. Especially tensile properties measured at elevated temperature should be high, that means highest maximal elongation at break, simultaneously high Modulus 300 % values and highest maximal tensile strength should be reached. The inventive examples data shown in Table 5 exhibit at low and high temperatures the highest tensile strength at high Modulus 300 %, compared to all comparative examples, provided in the same Table. It is obvious from the example formulations in Tables 2 and 2.1, when correlated with test data provided in Table 5; the inventive rubber composition examples of the present invention provide improved tensile strength and elongation at break as a proof of performance improvement, when high amount of high CTAB SA silica is used with relatively high amount of silane in 100 phr natural rubber used composition, and when lower carbon black is formulated in the rubber formulations as well. It can be concluded here that when high amount of silica (higher than 40 phr) having CTAB SA of 175 m2 / g or above with silane amount of higher than 8 phr, ASS of above 9000 phr*m2 / g, and SF value of higher than 0,090 g / m², formulated in 100 phr natural rubber together with limited or no carbon black, improved reinforcement and tensile properties have been obtained, when compared to the carbon black example (control example) or the examples with low CTAB SA silica or when lower amount natural rubber with higher amount of carbon black have been used in the rubber formulations. Table 6 reflects mainly improved processability proved with the marching modulus data. Additionally a good, that means low or comparable DIN abrasion have been obtained for some of measured examples. It is also obvious from Tables 2 and 2.1 when correlated with test data provided in Table 6 and Fig.1, the inventive rubber composition examples (e.g.: Inventive Examples 5 to 7) of the present invention provide either improved (e.g.: when compared to comparative examples 1 to 7), especially when compared to Comparative Examples 6 and 7or comparable processability in rubber formulation (when compared to carbon black comparative example 1). As explained in the disclosure, a disadvantage of the use of high silane amounts in natural rubber based rubber mixtures is the high marching modulus. Even if high silane amounts together with the silica is used in such rubber formulations not only natural rubber is used, but also synthetic rubber is needed together with carbon black of at least 5 phr. With the present invention it is proved that 100 phr of natural rubber 202400016 Foreign Filing 27 can be formulated with no or very limited amount black (2 phr or less) together with the claimed silica-silane system. Accordingly it is proved with the data that either improvements or comparable performance and / or processability is obtained with the claimed rubber formulations. It is already known in the field that carbon black is the best performing material when used in rubber formulations as easy to process reinforcing filler, but the industry is always trying to reduce the use of carbon black by replacing it with more sustainably silica - silane systems due to the fact that such systems always are superior regarding the hysteresis loss, that means the silica - silane system provides always lower rolling resistance and therefore lower fuel consumption that finally results in lower CO2 emissions, when e.g. using such systems as reinforcing filler in truck tire tread or sidewall compounds. Most important is, that the inventive examples also provide simultaneously an equivalent wear performance proven by the shown abrasion resistance relevant parameter shown in Table 5. With the inventive examples 5 to 7 provided hereby, once the claimed ultra accelerator has been used within the composition, improved marching modulus obtained when compared to comparative examples 1 to 7, or by having nearly zero marching modulus when compared to control example as well. Especially when Comparative Example 6 and 7 are directly compared to Inventive Example 7, wherein the same amount of ultra-accelerator retarder system is formulated, it is seen that marching modulus is dramatically decreased, and additionally DIN abrasion is either decreased or comparable with the comparative examples. Inventive examples 5 and 6 also confirms the improvements based on either different amount of ultra-accelerator (In. Ex.5) or an increased amount of silane (Inv. Ex.6) used within the rubber formulations. It can be concluded here that particularly good processibility of the rubber mixture of the invention together with optimized tensile properties are achieved in this way of comprising high amount of high CTAB SA silica, well balanced with the ratio of silane in a natural rubber and combined with an ultra- accelerator as claimed within the present invention.

Claims

202400016 Foreign Filing 28 CLAIMS 1. A rubber composition comprising at least one natural rubber (NR), at least one precipitated silica and at least one silane or at least one silane-azodicarbonamide mixture; wherein the silica has a CTAB SA of 175 m2 / g or more, and in an amount of at least 40 phr, measured in accordance with ISO 5794-1G standard, and the silane or silane-azodicarbonamide mixture is in an amount of between 8 phr < to ≤ 18 phr; and wherein; the natural rubber in an amount of 100 phr and, carbon black in an amount of 2 phr or less, or no carbon black is used in the rubber composition.

2. The rubber composition according to claim 1, wherein the silica has a CTAB SA in the range between 175 m² / g ≤ CTAB SA ≤ 250 m² / g.

3. The rubber composition according to claim 1 or 2, wherein the rubber composition comprises ≥ 45 phr silica, and preferable ≥ 50 phr silica.

4. The rubber composition according to any preceding claims, comprises at least one silane or silane- azodicarbonamide mixture in an amount of between 10 phr ≤ to ≤17phr.

5. The rubber composition according to any preceding claims, the mixture comprises at least one silane of formula (I); (R1)ySi-R2-Sx-R2-Si(R1)y(I) wherein; R1represents C1-C10-alkoxy groups, preferably methoxy or ethoxy groups, phenoxy group or alkylpolyether group –O-(R6-O)r-R7where R6represents a branched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30 hydrocarbon group, preferably - CH2-CH2-, r is an integer from 1 to 30, preferably 3 to 10, and R7represents unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl groups, preferably represents C13H27 alkyl group, wherein y is 1 to 3, preferably 3, and R2represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, preferably C1-C20, particularly preferably C1- C10, very particularly preferably C2-C7-, especially preferably CH2CH2 and CH2CH2CH2, x is the average sulfur chain distribution, wherein x is 1 to 12, preferably 2 to 10, more preferably 2 to 4, OR The composition comprises at least silane-azodicarbonamide mixture; wherein the silane-azodicarbonamide mixture comprises at least one silane of formula (I); (R1)ySi-R2-Sx-R2-Si(R1)y(I) wherein;202400016 Foreign Filing 29 R1represents C1-C10-alkoxy groups, methoxy or ethoxy groups, phenoxy group or alkylpolyether group –O-(R6-O)r-R7where R6represents a branched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30 hydrocarbon group, preferably -CH2-CH2-, r is an integer from 1 to 30, preferably 3 to 10, and R7represents unsubstituted or substituted, branched or unbranched monovalent alkyl, alkenyl, aryl or aralkyl groups, preferably represents C13H27 alkyl group, wherein y is 1 to 3, preferably 3, and R2represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, preferably C1-C20, particularly preferably C1- C10, very particularly preferably C2-C7-, especially preferably CH2CH2 and CH2CH2CH2, x is the average sulfur chain distribution, wherein x is 1 to 12, preferably 2 to 10, more preferably 2 to 4, and at least one azocarbonyl-functionalized silane of formula (II) (R1)3-a(R2*)aSi-R3-NH-C(O)-N=N-R4(II), wherein R2*represents -OH, C6-C20-aryl groups, C1-C10-alkyl groups, C2-C20-alkenyl group, C7-C20- aralkyl group or halogen, a is 0 to 3, R3represents a branched or unbranched, saturated or unsaturated, aliphatic, aromatic or mixed aliphatic / aromatic divalent C1-C30-hydrocarbon group, R4represents a substituted or unsubstituted aryl or substituted or unsubstituted alkyl group,and at least one azodicarbonamide compound of formula (III). R5-NH-C(O)-N=N-C(O)-NH-R5(III), wherein R5represents a branched or unbranched, saturated or unsaturated, aliphatic or cyclic monovalent C1-C30-hydrocarbon group or a substituted or unsubstituted aryl group.

6. The rubber composition according claim 5, wherein the silane of formula (I) is selected from [(EtO)3Si(CH2)3]2S, [(EtO)3Si(CH2)3]2S2, [(EtO)3Si(CH2)3]2S3 or [(EtO)3Si(CH2)3]2S4.

7. The rubber composition according to claim 5, wherein the azocarbonyl-functionalized silane of formula (II) is selected from (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-phenyl, (CH3O-)3Si-(CH2)3-NH- CO-N=N-phenyl or (CH3CH2O-)3Si-(CH2)3-NH-CO-N=N-(p-nitrophenyl) and the azodicarbonamide compound of formula (III) is selected from CH3(CH2)5-NH-C(=O)-N=N- C(=O)-NH-(CH2)5-CH3, CH3(CH2)7-NH-C(=O)-N=N-C(=O)-NH-(CH2)7-CH3, CH3(CH2)3-CH(C2H5)- CH2-NH-C(=O)-N=N-C(=O)-NH-CH2-CH(C2H5)-(CH2)3-CH3 or CH3 –(CH2)3-CH(C3H7)-CH2-CH2- NH-C(=O)-N=N-C(=O)-NH-CH2-CH2-CH(C3H7)–(CH2)3 -CH3.

8. The rubber composition according to any preceding claims, wherein the rubber composition comprises at least one natural rubber selected from SIR (Indonesia), SMR (Malaysia), SVR (Vietnam), STR (Thailand) rubbers, preferably selected from SIR 3CV50, SIR 3CV60, SIR 3L,202400016 Foreign Filing 30 SIR 3WF, SIR 5, SIR 10, SIR 10VK, SIR SIR, 20VK, SMR 5, SMR 10, SMR 20, SMR GP, SMR CV 50, SMR CV60, deproteinized natural rubber such as P10, epoxidized NR, SMR L, SMR 10 CV, SMR 20 CV TSR 20, TSR 10, TSR 5, TSR L, TSR CV or combinations thereof.

9. The rubber composition according to any preceding claims, wherein the rubber mixture further comprises at least one accelerator (ACC) in an amount of ≥ 0,50 phr, preferably ≥ 0,60 phr and more preferably between 0,75 ≤ ACC > 3 phr.

10. The rubber composition according to claim 9, wherein the accelerator is selected from sulfenamides, dithiocarbamates, preferably from tetra-alkyl thiuram disulfide (TATD), and more preferably tetra-methyl thiuram disulfide (TMTD), or mixtures thereof.

11. The rubber composition according to any preceding claims, wherein the rubber mixture further comprises a retarder in an amount between 0.1 to 0.5 phr.

12. The rubber composition according to claim 11, wherein the retarder selected from N-Phenyl-N- (trichlormethylsulfenyl)-benzolsulfonamid, WK-901 (1,3-bis(citraconimidomethyl)benzene) or N- (Cyclohexylthio) phthalimide (PVI), preferably PVI.

13. The rubber composition according to any preceding claims, wherein the rubber mixture comprises TMTD accelerator in an amount of ≥ 0,50 phr, preferably ≥ 0,60 phr and more preferably between 0,75 ≤ ACC > 3 phr, and N-(Cyclohexylthio) phthalimide (PVI) retarder in an amount between 0.1 to 0.5 phr.

14. Use of rubber composition according to any preceding claims for production of tires, vehicle tire formulation, especially in a truck tire formulation, cable sheaths, hoses, drive belts, conveyor belts, roller coverings, footwear soles, sealing rings or damping elements.

15. A vulcanizate obtained by sulfur vulcanization of the at least one rubber composition as claimed in any preceding claims.

16. A vehicle tire, preferably a truck tire comprising at least one vulcanizate in a tread or sidewall according to claim 15.