Rubber composition, preparation method thereof and OTR engineering tire using rubber composition

Abstract

The invention belongs to the technical field of rubber, and particularly relates to a rubber composition, a preparation method thereof and an OTR engineering tire using the rubber composition. The rubber composition disclosed by the invention is prepared from the following components in parts by mass: 100 parts of diene rubber, 0 to 1.5 parts of tetrazine compound, 0.2 to 1.5 parts of pyrazolone compound, 0 to 30 parts of liquid rubber, 20 to 100 parts of reinforcing filler, 0 to 5 parts of silane coupling agent, 2 to 10 parts of vulcanization activator, vulcanization accelerator, vulcanizing agent, antioxidant, resin and plasticizer. The proportions of the tetrazine compound and the liquid rubber are not zero at the same time. The heat generated by the OTR engineering tire can be obviously reduced, and the damage resistance of the tire is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and in particular relates to a rubber composition and a preparation method thereof, and an OTR engineering tire using the same. Background Art

[0002] When operating engineering trucks under harsh road conditions, the tires are exposed to high loads and cyclic deformation, exposing the rubber to damaging conditions such as heat, oxygen, fatigue, and cutting and tearing. Reducing tire heat generation and improving tire resistance to damage, such as cut and tear resistance, are key to extending tire life. Traditional methods, such as changing the type of rubber or increasing the amount of silica used, often have performance limitations. Because low-heat rubber materials require low energy dissipation (hysteresis loss), while high cut and tear resistance under large deformations requires high energy dissipation capacity, low heat generation and high cut and tear resistance are contradictory. While reducing heat generation, cut and tear resistance often deteriorate, and improving one property often comes at the expense of other properties, making it difficult to improve the overall tire life. In practical applications, rubber compositions primarily based on styrene-butadiene rubber (SBR) are often used for harsh road conditions to improve cut and tear resistance, but this high heat generation can affect service life. In less harsh road conditions, rubber compositions primarily based on natural rubber are often used to reduce heat generation and extend service life, but this also reduces service life due to poor cut resistance. Therefore, achieving both low heat generation and high cut and tear resistance is currently difficult.

[0003] In response to this technical demand, patent publications CN110392713B, CN108026332B, CN110382611B, CN110382612B, CN110382554B, and CN110461931B disclose rubber compositions and tires. By combining a specific rubber component, a tetrazine compound represented by the general formula (4) or its salt, and carbon black, a rubber composition can be provided that not only imparts excellent low heat buildup but also excellent wear resistance to the tire. However, these patent publications do not provide any description or example data for cut and tear resistance. In addition, by using the rubber composition of the invention to make a tire, not only can the rolling resistance of the tire be reduced, and the heat buildup of the tire be reduced, but also the wear resistance can be improved, thereby providing a low fuel consumption tire for large vehicles. However, wear resistance is the anti-wear performance under small deformation under mild road conditions, which is not inconsistent with the low heat generation under high dispersion of fillers in rubber, but is inconsistent with the rubber action mechanism of cut and tear resistance under large deformation under harsh road conditions. Therefore, the tires made of this rubber composition have weak or even deteriorated anti-destructive properties such as cut resistance and tear resistance, which cannot meet the use requirements of OTR engineering tires under harsh road conditions.

[0004] Patent Publication No. CN112533991B discloses a rubber composition, a rubber material, and their uses, as well as additives represented by general formulas (2) and (3), a rubber composition capable of exhibiting low heat generation, tear strength, and durability; and a rubber composition having excellent low heat generation, tear strength, and durability. In embodiments where the amount of natural rubber (NR) or polyisoprene rubber (IR) is 100 parts or more than 50 parts, pyrazolone compounds exhibit good low heat generation, tear strength, and durability; however, there is no embodiment data showing that low heat generation, tear strength, and durability are simultaneously improved when the amount of synthetic rubber such as styrene-butadiene rubber (SBR) exceeds 50 parts. Since pyrazolone compounds have a higher reactivity with natural rubber than with synthetic rubbers such as styrene-butadiene rubber, pyrazolone compounds can achieve good low heat generation and tear strength in rubber compositions primarily composed of natural rubber (in an amount exceeding 50 parts), but cannot simultaneously achieve low heat generation and high tear strength in rubber compositions primarily composed of styrene-butadiene rubber (in an amount exceeding 50 parts). Therefore, the low heat generation, cut resistance, tear resistance and other effects of the tire made of the styrene-butadiene rubber composition are weak or even deteriorate, and cannot meet the use requirements of OTR engineering tires under harsh road conditions.

[0005] Therefore, how to provide a rubber composition that reduces heat generation and improves anti-damage performance and a preparation method thereof are technical problems that need to be solved urgently by those skilled in the art. Summary of the Invention

[0006] In view of this, the first object of the present invention is to provide a rubber composition that can be used in OTR engineering tires to reduce heat generation and improve damage resistance in order to address the problems existing in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] A rubber composition comprises the following raw materials in parts by mass: 100 parts of diene rubber, 0-1.5 parts of tetrazine compounds, 0.2-1.5 parts of pyrazolone compounds, 0-30 parts of liquid rubber, 20-100 parts of reinforcing fillers, 0-5 parts of silane coupling agents, and 2-10 parts of vulcanization activators, wherein the proportions of the tetrazine compounds and the liquid rubber are not both zero; wherein,

[0009] The structure of the tetrazine compound is:

[0010]

[0011] where X 1 , X 2 represents a heterocyclic group which may have a substituent, wherein the substituent is an alkyl group, an aralkyl group, an aryl group or a heterocyclic group;

[0012] The structure of the pyrazolone compound is:

[0013]

[0014] wherein R1, R2, R3, and R4 each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; R3 and R4 may be linked to form an alkylene group, and any two of R2, R3, and R4 may be linked together to form an alkylene group; R5, R7, and R8 each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; R6 represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; and each of the aforementioned groups may independently have one or more substituents;

[0015] The structure of the liquid rubber is:

[0016]

[0017]

[0018] Wherein, l, m, and n are any integers from 1 to 1000.

[0019] Preferably, the rubber composition comprises the following raw materials, in parts by mass: 100 parts of diene rubber, 0.2-1.5 parts of tetrazine compound, 0.2-1.5 parts of pyrazolone compound, 0-30 parts of liquid rubber, 20-100 parts of reinforcing filler, 0-5 parts of silane coupling agent, and 2-10 parts of vulcanization activator.

[0020] Preferably, the rubber composition comprises the following raw materials, in parts by mass: 100 parts of diene rubber, 0-1.5 parts of tetrazine compound, 0.2-1.5 parts of pyrazolone compound, 1-30 parts of liquid rubber, 20-100 parts of reinforcing filler, 0-5 parts of silane coupling agent, and 2-10 parts of vulcanization activator.

[0021] Preferably, the rubber composition comprises the following raw materials, in parts by mass: 100 parts of diene rubber, 0.2-1.5 parts of tetrazine compound, 0.2-1.5 parts of pyrazolone compound, 1-30 parts of liquid rubber, 20-100 parts of reinforcing filler, 0-5 parts of silane coupling agent, and 2-10 parts of vulcanization activator.

[0022] In the present invention, the vulcanization activator is zinc oxide and stearic acid.

[0023] It is worth noting that tetrazine compounds can react with the double bonds of synthetic diene rubbers to form a trans-Diels-Alder reaction, which has the effect of reducing heat generation. Pyrazolone compounds can be complexed with zinc oxide to form a weak sacrificial bond network, thereby improving the anti-destruction performance of the rubber. The use of tetrazine compounds and pyrazolone compounds can not only reduce the heat generation of synthetic rubber but also improve the cut resistance of the rubber, and the two have a certain synergistic effect. The liquid rubber containing special functional groups has a certain effect of improving the anti-destruction effect when added alone, but the hysteresis loss or heat generation does not change, and when added together, it will have a synergistic effect with pyrrolidone, which will greatly improve the anti-destruction performance and reduce the heat generation to a certain extent. The present invention can significantly reduce the heat generation of OTR engineering tires while improving the anti-destruction performance of the tires.

[0024] Furthermore, the rubber composition further comprises a vulcanization accelerator, a vulcanizing agent, an antioxidant, a resin and a plasticizer.

[0025] In the present invention, the vulcanization accelerator is a combination of one or more of thiazoles, thiurams, sulfenamides, dithiocarbamates, xanthates, guanidines, and thioureas. Preferably, it is a combination of one or more of diphenylguanidine and N-cyclohexane-2-benzothiazolesulfenamide. The weight proportion of the vulcanization accelerator in the rubber composition is 0.5-4 parts, preferably 0.8-3 parts, and more preferably 1-2.5 parts.

[0026] The vulcanizing agent is sulfur, and the weight proportion of the vulcanizing agent in the rubber composition is 0.5-5 parts, preferably 0.8-3 parts, and more preferably 1-2 parts.

[0027] And, the present invention selects, antioxidant 6PPD, dicyclopentadiene DCPD resin and plasticizer.

[0028] In the present invention, the rubber composition further comprises a protective agent, microcrystalline wax.

[0029] Furthermore, the diene rubber is a combination of one or more of modified or unmodified natural rubber, polyisoprene rubber, polybutadiene rubber, butadiene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-diene monomer copolymer, styrene-isoprene-styrene ternary block copolymer rubber, and styrene-butadiene-styrene ternary block copolymer rubber.

[0030] Furthermore, the diene rubber is composed of 50-100 parts by mass of one or more of modified or unmodified styrene-butadiene copolymer rubber and polybutadiene rubber, and 0-50 parts by mass of one or more of modified or unmodified natural rubber and polyisoprene rubber.

[0031] Preferably, the diene rubber is composed of 60-100 parts by mass of a combination of one or more of modified or unmodified styrene-butadiene copolymer rubber and polybutadiene rubber, and 0-40 parts by mass of a combination of one or more of modified or unmodified natural rubber and polyisoprene rubber.

[0032] In the present invention, the styrene-butadiene copolymer rubber contains 5%-40%wt of styrene, and the styrene-butadiene copolymer rubber is a combination of one or more of the following elastomeric substances: unmodified solution-polymerized styrene-butadiene rubber, unmodified emulsion-polymerized styrene-butadiene rubber, end-group-modified solution-polymerized styrene-butadiene rubber, end-group-modified emulsion-polymerized styrene-butadiene rubber, main-chain-modified solution-polymerized styrene-butadiene rubber, and main-chain-modified emulsion-polymerized styrene-butadiene rubber.

[0033] It is worth noting that the use of the above-mentioned rubber can both reduce tire heat generation and improve anti-destruction performance.

[0034] Considering the high molecular weight and strong damage resistance of emulsion polystyrene butadiene rubber, in some embodiments, emulsion polystyrene butadiene rubber is more preferred among styrene butadiene rubbers. After modification by adding tetrazine and pyrazolone compounds, it has a better balance of cut resistance, heat generation and processing performance.

[0035] In other embodiments, nickel catalytic system, lithium catalytic system and rare earth catalytic system are preferred in polybutadiene rubber. The addition of modified polybutadiene rubber can effectively balance the wear resistance, heat generation and processing performance as well as the aging resistance and fatigue crack growth performance.

[0036] Furthermore, the tetrazine compound is a combination of one or more of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3-pyridyl)-1,2,4,5-tetrazine, and 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine, and the tetrazine compound accounts for 0.3-1.2 parts by mass in the rubber composition.

[0037] In the present invention, the tetrazine compound is preferably 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, and its content in the rubber composition is preferably 0.3-1 parts by mass, more preferably 0.3-0.8 parts by mass.

[0038] Furthermore, the pyrazolone compound is a combination of one or more of 3-methyl-5-pyrazolone, 3-phenyl-5-pyrazolone, 3-ethyl-5-pyrazolone, 3-propyl-5-pyrazolone, and 3-butyl-5-pyrazolone, and the proportion of the pyrazolone compound in the rubber composition is 0.3-1.2 parts by mass.

[0039] In the present invention, the pyrazolone compound is preferably a combination of one or more of 3-methyl-5-pyrazolone and 3-phenyl-5-pyrazolone, more preferably 3-methyl-5-pyrazolone. The pyrazolone compound preferably accounts for 0.3-1 parts by mass, more preferably 0.3-0.8 parts by mass, in the rubber composition.

[0040] Furthermore, the liquid rubber is a combination of one or more of modified or unmodified liquid polyisoprene, liquid hydrogenated polyisoprene, liquid polybutadiene, liquid styrene-isoprene copolymer, liquid isoprene-butadiene copolymer, and liquid styrene-butadiene copolymer, and the molecular weight of the liquid rubber is 500-100,000 g / mol, and the proportion of the liquid rubber in the rubber composition is 3-20 parts by mass.

[0041] In the present invention, the liquid rubber is preferably a combination of one or more of maleic anhydride-modified liquid polyisoprene, carboxylic acid acrylate-modified liquid polyisoprene, maleic anhydride-modified liquid polybutadiene, carboxylic acid acrylate-modified liquid polybutadiene, and maleic anhydride monomethyl ester-modified liquid polyisoprene, and is further preferably a combination of one or more of maleic anhydride-modified liquid polyisoprene, carboxylic acid acrylate-modified liquid polyisoprene, and maleic anhydride monomethyl ester-modified liquid polyisoprene. The molecular weight of the liquid rubber is preferably 500-80,000 g / mol, and is further preferably 500-50,000 g / mol. The proportion of the liquid rubber in the rubber composition is preferably 5-15 parts by mass, and is further preferably 5-10 parts by mass.

[0042] It is worth noting that the present invention utilizes the aforementioned tetrazine compounds and pyrazolone compounds to graft-modify styrene-butadiene rubber and natural rubber, thereby improving filler dispersion, reducing heat generation, and enhancing the final product's resistance to damage. The addition of liquid rubber creates a synergistic effect with the tetrazine and pyrazolone compounds, further reducing heat generation and improving resistance to damage, such as cut and tear resistance.

[0043] Furthermore, the reinforcing filler is a combination of one or more of modified or unmodified carbon black, acetylene black, white carbon black, carbon nanotubes, graphite, and graphene;

[0044] The silane coupling agent is a combination of one or more of bis-[3-(triethoxysilyl)propyl]-tetrasulfide (Si 69), bis-[3-(triethoxysilyl)propyl]-disulfide (Si 75), 3-octanoylthio-1-propyltriethoxysilane (NXT), γ-mercaptopropylethoxybis-(propyl-hexaethoxysiloxane) (Si 747) and mercaptoalkoxy-ethoxysilane (Si 363).

[0045] In the present invention, the preferred reinforcing filler is a combination of one or more of carbon black and white carbon black.

[0046] In some embodiments, the reinforcing filler consists of 20-70 parts by mass of carbon black and 0-30 parts by mass of white carbon black; preferably, consists of 20-60 parts by mass of carbon black and 0-25 parts by mass of white carbon black; more preferably, consists of 30-60 parts by mass of carbon black and 0-20 parts by mass of white carbon black.

[0047] And, the specific surface area of the carbon black is 20-160m 2 / g, the specific surface area of white carbon black is 60-250m 2 / g. More preferably, the specific surface area of the carbon black is 40-140m 2 / g, the specific surface area of white carbon black is 90-200m 2 / g.

[0048] In the present invention, the carbon black is a combination of one or more of N110, N121, N134, N220, N231, N234, N242, N293, N299, N315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582, N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990, and N991; the iodine absorption value of the carbon black is 5-150 g / kg, and the DBP absorption value is 30-150 cm 3 / 100g.

[0049] In the present invention, the silane coupling agent is preferably a combination of one or more of bis-[3-(triethoxysilyl)propyl]tetrasulfide (Si 69), bis-[3-(triethoxysilyl)propyl]disulfide (Si 75), and 3-octanoylthio-1-propyltriethoxysilane (NXT), and more preferably bis-[3-(triethoxysilyl)propyl]disulfide (Si 75) or 3-octanoylthio-1-propyltriethoxysilane (NXT). The proportion of the silane coupling agent in the rubber composition is preferably 0-4 parts by mass, and more preferably 0-3 parts by mass.

[0050] It is worth noting that the present invention can better balance the low heat generation and improved anti-damage performance of the final product by adjusting the types and amounts of carbon black, white carbon black and silane coupling agent.

[0051] The second object of the present invention is to provide a method for preparing the rubber composition as described above.

[0052] A method for preparing the rubber composition as described above comprises the following steps:

[0053] Step (1) accurately weighing diene rubber, tetrazine compound, pyrazolone compound, liquid rubber, reinforcing filler, silane coupling agent, vulcanization accelerator, vulcanizing agent, antioxidant, vulcanization activator, resin and plasticizer;

[0054] Step (2) mixing a portion of the diene rubber, the tetrazine compound, the antioxidant and the reinforcing filler, and subjecting the mixture to a mixing reaction at 120-180° C. for 60-300 seconds, and then cooling the mixture to obtain a material A, wherein the discharge temperature is 120-180° C.;

[0055] Step (3) mixing the remaining diene rubber, pyrazolone compound, liquid rubber, silane coupling agent, vulcanization activator, resin and plasticizer with material A, and performing a mixing reaction at 120-180° C. for 60-300 seconds, and then cooling to obtain material B, wherein the discharge temperature is 120-180° C.;

[0056] Step (4) adding a vulcanizing agent and a vulcanization accelerator to material B, mixing and discharging the mixture to obtain the rubber composition.

[0057] In the present invention, the tetrazine compound is added in step (2), the pyrazolone compound and the liquid rubber are all added in step (3), and the antioxidant can be partially or completely added in step (2), step (3) or step (4).

[0058] In some embodiments, the "part of the diene rubber" in step (2) is a combination of one or more of modified or unmodified styrene-butadiene copolymer rubber and polybutadiene rubber, and the "remaining part of the diene rubber" in step (3) is a combination of one or more of modified or unmodified natural rubber and polyisoprene rubber.

[0059] In some embodiments, part or all of the carbon black in the reinforcing filler can be added in step (2) or step (3); part or all of the white carbon black in the reinforcing filler can be added in step (2) or step (3), and part or all of the silane coupling agent can be added in step (2) or step (3) according to the proportion of white carbon black added.

[0060] In the present invention, the mixing reaction at 120-180°C in step (2) is preferably carried out for 120-300 seconds, more preferably 150-300 seconds; the discharge temperature is 120-180°C, preferably 130-170°C, more preferably 140-160°C.

[0061] In the present invention, the mixing reaction at 120-180°C in step (3) is preferably carried out for 120-300 seconds, more preferably 150-300 seconds; the discharge temperature is 120-180°C, preferably 130-170°C, more preferably 140-160°C.

[0062] It is worth noting that, by adding a small amount of tetrazine compounds, pyrazolone compounds, and liquid rubber, and applying an optimized rubber refining process that is consistent with the reaction of tetrazine compounds, pyrazolone compounds, and rubber, the composition can simultaneously reduce the hysteresis loss and heat generation of the rubber, and improve the anti-destructive properties such as cut resistance and tear resistance. The preparation method of the present invention is simple to operate and highly practical.

[0063] A third object of the present invention is to provide a tire.

[0064] An OTR engineering tire comprises the rubber composition described above.

[0065] Compared with the prior art, the rubber composition disclosed in the present invention not only reduces the hysteresis loss and heat generation of the rubber, but also improves the anti-destructive properties of the rubber, such as cut resistance and tear resistance, which is a two-way improvement that cannot be achieved by traditional technology. BRIEF DESCRIPTION OF THE DRAWINGS

[0066] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative work.

[0067] Figure 1 The invention provides a high-temperature slow tearing energy test specimen. DETAILED DESCRIPTION

[0068] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0069] The term "embodiment" is used herein specifically to describe any embodiment as "exemplary," and should not be construed as superior or preferable to other embodiments. Performance indicators in the embodiments of this application were tested using conventional testing methods in the art, unless otherwise specified. It should be understood that the terms used in this application are intended solely to describe specific implementations and are not intended to limit the disclosure herein.

[0070] Unless otherwise specified, the technical and scientific terms used herein have the same meanings as commonly understood by ordinary technicians in the technical field to which this application belongs; other experimental methods and technical means not specifically specified in this application refer to experimental methods and technical means commonly used by ordinary technicians in this field.

[0071] In order to better illustrate the content of this application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that this application can be implemented without certain specific details. In the examples, some methods, means, instruments, equipment, etc. well known to those skilled in the art are not described in detail in order to highlight the main purpose of this application.

[0072] Under the premise of no conflict, the technical features disclosed in the embodiments of this application can be combined arbitrarily, and the resulting technical solutions belong to the contents disclosed in the embodiments of this application.

[0073] The present invention provides a rubber composition, a preparation method thereof, and an OTR tire using the same. The rubber composition (in parts by mass) includes 100 parts of diene rubber, 0-1.5 parts of tetrazine compounds, 0.2-1.5 parts of pyrazolone compounds, 0-30 parts of liquid rubber, 20-100 parts of reinforcing fillers, 0-5 parts of silane coupling agents, 2-10 parts of vulcanization activators, vulcanization accelerators, vulcanizing agents, antioxidants, resins, and plasticizers. The proportions of the tetrazine compounds and the liquid rubber are not zero at the same time. The present invention can significantly reduce the heat generation of OTR engineering tires while improving the anti-destruction performance of the tires.

[0074] In order to better understand the present invention, the present invention is further specifically described through the following examples, but it should not be understood as limiting the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the above invention content are also considered to fall within the scope of protection of the present invention.

[0075] The standards and methods for testing the rubber composition of the present invention in the following examples are as follows:

[0076] 1) Mooney viscosity: Refer to ASTM D1646-2007, test conditions are ML (1+4) 100°C. The larger the index, the higher the Mooney viscosity.

[0077] 2) Mooney Scorch: Refer to ASTM D1646-2007, test temperature is 130°C. The larger the index, the longer the scorch time.

[0078] 3) Hardness: Shore hardness test, refer to ASTM D2240-2010. The larger the index, the higher the hardness.

[0079] 4) MA100: 100% tensile modulus test, referring to ASTM D412-2006, taking the modulus at 100% elongation, and the test environment temperature is 23±2°C. The larger the index, the higher the tensile modulus.

[0080] 5) Tensile strength and elongation at break: Refer to ASTM D412-2006, dumbbell-shaped specimens, test speed 500 mm / min, test ambient temperature 23 ± 2°C. A larger index indicates higher tensile strength.

[0081] 6) Hysteresis Loss Factor: Tested using Metravib DMA at 60°C, 10 Hz, dynamic deformation 0.07%-50%, in plane shear mode. A smaller index indicates lower hysteresis loss, and therefore lower rolling resistance and heat generation.

[0082] 7) High temperature slow tearing energy: Use a sample with a width of 40mm, a height of 65mm, and a notch of 10mm (see Figure 1 ), test speed 50mm / min, test environment temperature 100±5℃. The larger the index, the higher the high-temperature tear energy and the better the tear resistance.

[0083] 8) Dynamic cutting loss of rubber: Manufacturer: Beijing Wanhui Yifang, Test conditions: Strike frequency 120 / min; Rubber wheel speed 720 rpm; Test method: The mass of the rubber wheel 5 minutes after pre-cutting is recorded as m0, and the mass after 20 minutes of cutting is recorded as m1; Data is recorded as the cutting loss mass per minute: Δm = (m0-m1) / 15min; the smaller the index, the smaller the cutting mass loss and the better the cut and tear resistance.

[0084] The raw materials used in the embodiments of the present invention are as follows:

[0085] Natural rubber: STR20, Sinochem International Holdings Co., Ltd.

[0086] SBR1502 (Styrene-Butadiene Rubber) Shenhua Chemical Industry Co., Ltd.

[0087] BR9000 (polybutadiene rubber) Sinopec Qilu Petrochemical Company

[0088] Tetrazine compounds: 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, Otsuka Chemical Co., Ltd.

[0089] Pyrazolone compounds: 3-Methyl-5-pyrazolone, Tokyo Chemical Industry Development Co., Ltd.

[0090] Liquid rubber: Liquid polyisoprene modified with monomethyl maleic anhydride, Kuraray Co., Ltd.

[0091] HD165MP (white carbon black) Wuxi Quecheng Silicon Co., Ltd.

[0092] N234, N220, N330, N115: Cabot Carbon Black

[0093] Si 69: Nanjing Shuguang Chemical Group Co., Ltd.

[0094] Si 75: Nanjing Shuguang Chemical Group Co., Ltd.

[0095] EP-140: Dicyclopentadiene DCPD resin, Japan JXTG Company

[0096] 6PPD (antioxidant): Shandong Shangshun Chemical Co., Ltd.

[0097] Stearic acid: Sichuan Tianyu Oil Chemical Co., Ltd.

[0098] Zinc oxide: Dalian Zinc Oxide Co., Ltd.

[0099] Microcrystalline wax: Yanggu Huatai Chemical Co., Ltd.

[0100] NS (N-tert-butyl-2-benzothiazole sulfenamide): Shandong Shangshun Chemical Co., Ltd.

[0101] Sulfur: Shandong Shangshun Chemical Co., Ltd.

[0102] Example 1

[0103] The raw materials used in Comparative Examples 1-1 to 1-3 and Examples 1-1 to 1-5 of the present invention are shown in the following table, all expressed in parts by mass. Examples 1-1 to 1-5 are rubber compositions using a combination of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone. Comparative Examples 1-2 and 1-3 are rubber compositions using either 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine or 3-methyl-5-pyrazolone alone.

[0104] Table 1: Formulas of Comparative Examples 1-1 to 1-3 and Examples 1-1 to 1-5

[0105]

[0106] The above schemes all adopt the following preparation method:

[0107] Step (1) weighing the raw materials according to the above weight; step (2) mixing SBR1502 rubber for 30 seconds, adding tetrazine compound, 10 parts of carbon black N220 and antioxidant 6PPD, mixing reaction treatment time at 130-150°C for 150 seconds, and draining at 150°C to obtain material A; step (3) mixing the remaining raw materials except vulcanizing agent and vulcanization accelerator with material A, mixing reaction treatment time at 140-160°C for 150 seconds, and draining at 160°C to obtain material B; step (4) adding vulcanizing agent and vulcanization accelerator to material B, mixing for about 180 seconds in an internal mixer, and draining at 110°C to obtain a rubber composition for reducing heat generation of OTR engineering tires while improving anti-destruction performance. The obtained rubber composition is then vulcanized at 150°C for 30 minutes for testing.

[0108] For Examples 1-1, 1-2, 1-3, 1-4, 1-5 and Comparative Examples 1-1, 1-2, 1-3, the performance tests were conducted before aging and after aging at 100°C for 72 hours, respectively. The results are shown in Table 2 below.

[0109] Table 2: Comparison of performance results of Examples 1-1 to 1-5 and Comparative Examples 1-1 to 1-3

[0110]

[0111] *The test results of rubber compositions are expressed in the form of indices.

[0112] The calculation formula is: test item = (Example / Comparative Example 1-1) × 100.

[0113] Compared with Comparative Example 1-1, Examples 1-1 to 1-5 showed a decrease in tensile strength and a slight increase in elongation at break, with little change in hardness. The 100°C high-temperature slow tear energy increased by 20-40%, hysteresis loss decreased by 17-24%, and cutting loss decreased by 12-19%. Comparative Example 1-2 showed a 25% reduction in cutting loss and a 50% increase in high-temperature slow tear energy, but hysteresis loss deteriorated. Similarly, Comparative Example 1-3 showed a 20% reduction in hysteresis loss and a 22% increase in high-temperature slow tear energy, but cutting loss deteriorated by 7%. After 3 days of thermo-oxidative aging in an oven at 100°C, the tensile strength of Examples 1-1 to 1-5 did not change much, the elongation was slightly improved, the 100°C high-temperature tear energy was increased by about 40%, the dynamic cutting loss was reduced to 15-20%, and the hysteresis loss was reduced by 15%-23%. Therefore, when 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone are used in combination in tires, it can not only improve the anti-destructive performance (cut resistance, tear resistance) but also reduce heat generation.

[0114] Example 2

[0115] The raw materials used in Comparative Examples 2-1 to 2-4 and Examples 2-1 to 2-4 of the present invention are shown in Table 3 below, all in parts by mass. Among them, Comparative Examples 2-2 and 2-3 are compositions to which different portions of liquid polyisoprene modified with maleic anhydride monomethyl ester are added; Comparative Example 2-4 is a rubber composition using only 3-methyl-5-pyrazolone; Examples 2-1 and 2-2 are rubber compositions in which 3-methyl-5-pyrazolone and liquid polyisoprene modified with maleic anhydride monomethyl ester are used in combination; Example 2-3 is a rubber composition in which 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone are used in combination; Example 2-4 is a rubber composition in which three compounds, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3-methyl-5-pyrazolone and liquid polyisoprene modified with maleic anhydride monomethyl ester, are used in combination.

[0116] Table 3: Formulas of Comparative Examples 2-1 to 2-4 and Examples 2-1 to 2-4

[0117]

[0118] The above schemes all adopt the following preparation method:

[0119] The method comprises the following steps: (1) weighing raw materials according to the above weight; (2) mixing SBR1502 and rubber for 30 seconds, adding a tetrazine compound, 10 parts of carbon black N220 and an antioxidant 6PPD, and performing a mixing reaction at 130-150° C. for 150 seconds, and discharging the rubber at 150° C. to obtain material A; (3) mixing STR20, 3-methyl-5-pyrazolone, liquid polyisoprene modified with maleic anhydride monomethyl ester, and the remaining raw materials except a vulcanizing agent and a vulcanization accelerator with material A, performing a mixing reaction at 140-160° C. for 150 seconds, and discharging the rubber at 160° C. to obtain material B; and (4) adding the vulcanizing agent and the vulcanization accelerator to material B, mixing the material in an internal mixer for about 180 seconds, and discharging the material at 110° C. to obtain a rubber composition for reducing heat generation of an OTR engineering tire while improving anti-destruction performance. The obtained rubber composition was then vulcanized at 150° C. for 30 minutes for testing.

[0120] The performance tests of Comparative Examples 2-1 to 2-4 and Examples 2-1 to 2-4 were conducted before aging and after aging at 100° C. for 72 hours, respectively. The results are shown in Table 4 below.

[0121] Table 4: Comparison of performance results of comparative examples 2-1 to 2-4 and examples 2-1 to 2-4

[0122]

[0123] *The test results of rubber compositions are expressed in the form of indices.

[0124] The calculation formula is: test item = (Example / Comparative Example 2-1) × 100.

[0125] Compared with Comparative Example 2-1, Comparative Examples 2-2, 2-3, and 2-4 showed increases in high-temperature slow tear energy by 19%, 21%, and 40%, respectively, with little change in hardness, and reductions in cutting loss by 13%, 15%, and 14%, respectively. Hysteresis loss showed little change or increased slightly. The elongation of Examples 2-1 and 2-2 increased by 39% and 49%, respectively, and the high-temperature slow tear energy increased by 400%-500%. Even after three days of thermal oxidative aging in a 100°C oven, the effect remained significantly improved. The tensile strength of Examples 2-3 and 2-4 improved, with significantly increased elongation at break and 36% and 47%, respectively. Cutting loss decreased by approximately 10-15%, and hysteresis loss decreased by 18-16%. Therefore, the combined use of liquid polyisoprene modified with 3-methyl-5-pyrazolone and maleic anhydride monomethyl ester can significantly improve the rubber's anti-damage properties and reduce heat generation to a certain extent when used in tires. When 3-methyl-5-pyrazolone, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and maleic anhydride monomethyl ester are used together in tires, the anti-damage performance of the rubber can be significantly improved and the heat generation can be significantly reduced.

[0126] Example 3

[0127] The raw materials used in Comparative Example 3-1 and Examples 3-1, 3-2, 3-3, and 3-4 of the present invention are shown in Table 5 below, all expressed in parts by mass. Examples 3-1 and 3-3, compared to Comparative Example 3-1, added 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone to the rubber composition; and Examples 3-2 and 3-4, compared to Comparative Example 3-1, added 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3-methyl-5-pyrazolone, and maleic anhydride monomethyl ester-modified liquid polyisoprene to the rubber composition.

[0128] Table 5: Formulas of Comparative Example 3-1 and Examples 3-1 to 3-4

[0129]

[0130] The above schemes all adopt the following preparation method:

[0131] The steps (1) weigh the raw materials according to the above weight; (2) mix the SBR1502 rubber for 30 seconds, add the tetrazine compound, 10 parts of carbon black N220 and the antioxidant 6PPD, and perform a mixing reaction at 130-150°C for 150 seconds, and discharge the rubber at 150°C to obtain material A; (3) mix the remaining raw materials except the vulcanizing agent and the vulcanization accelerator with material A, perform a mixing reaction at 140-160°C for 120 seconds, and discharge the rubber at 160°C to obtain material B; (4) add the vulcanizing agent and the vulcanization accelerator to material B, mix them in an internal mixer for about 180 seconds, and discharge the material at 110°C to obtain a rubber composition for reducing heat generation of OTR engineering tires on harsh roads while improving anti-destruction performance. The obtained rubber composition is then vulcanized at 150°C for 30 minutes for testing.

[0132] For Examples 3-1, 3-2, 3-3, 3-4 and Comparative Example 3-1, performance tests were conducted before aging and after aging at 100° C. for 72 hours. The results are shown in Table 6 below.

[0133] Table 6: Comparison of performance results of Examples 3-1 to 3-4 and Comparative Example 3-1

[0134]

[0135] *The test results of rubber compositions are expressed in the form of indices.

[0136] The calculation formula is: test item = (Example / Comparative Example 3-1) × 100.

[0137] Compared with Comparative Example 3-1, the elongation at break of Examples 3-1 and 3-3 increased by 20% and 18% respectively, the hysteresis loss was significantly reduced by 15% and 21% respectively, and the cutting loss was also reduced by 10% and 8% respectively, while the hardness remained almost unchanged. It can be seen that the more 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine is added, the greater the reduction in heat generation, but the cutting loss will deteriorate. The same rule is true after 3 days of thermal oxidation aging in a 100°C oven. Therefore, the use of 3-methyl-5-pyrazolone and 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine in combination can not only improve the anti-destructive performance of the rubber but also reduce heat generation when used in this OTR engineering tire formulation.

[0138] Compared with Examples 3-1 and 3-3, Examples 3-2 and 3-4 contain liquid polyisoprene modified with monomethyl maleic anhydride, and the elongation increases to 134% and 126%, respectively, the cutting loss decreases to 84% and 86%, respectively, and the hysteresis loss decreases to 83% and 74%, respectively. Therefore, the combination of 3-methyl-5-pyrazolone, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and liquid polyisoprene modified with monomethyl maleic anhydride can significantly improve the anti-destruction performance of the rubber and reduce heat generation when used in the OTR engineering tire formulation.

[0139] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A rubber composition, characterized in that The invention comprises the following raw materials in parts by mass: 100 parts of diene rubber, 0-1.5 parts of tetrazine compounds, 0.2-1.5 parts of pyrazolone compounds, 0-30 parts of liquid rubber, 20-100 parts of reinforcing fillers, 0-5 parts of silane coupling agents, and 2-10 parts of vulcanization activators, wherein the proportions of the tetrazine compounds and the liquid rubber are not zero at the same time; wherein, The structure of the tetrazine compound is: where X 1 , X 2 represents a heterocyclic group which may have a substituent, wherein the substituent is an alkyl group, an aralkyl group, an aryl group or a heterocyclic group; The structure of the pyrazolone compound is: wherein R1, R2, R3, and R4 each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; R3 and R4 may be linked to form an alkylene group, and any two of R2, R3, and R4 may be linked together to form an alkylene group; R5, R7, and R8 each independently represent a hydrogen atom, an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; R6 represents an alkyl group, an aralkyl group, an aryl group, or a heterocyclic group; and each of the aforementioned groups may independently have one or more substituents; The structure of the liquid rubber is: Wherein, l, m, and n are any integers from 1 to 1000.

2. The rubber composition according to claim 1, wherein Also included are vulcanization accelerators, vulcanizing agents, antioxidants, resins, and plasticizers.

3. The rubber composition according to claim 1, characterized in that The diene rubber is a combination of one or more of modified or unmodified natural rubber, polyisoprene rubber, polybutadiene rubber, butadiene rubber, styrene-butadiene copolymer rubber, ethylene-propylene-diene monomer copolymer, styrene-isoprene-styrene terblock copolymer rubber, and styrene-butadiene-styrene terblock copolymer rubber.

4. The rubber composition according to claim 3, characterized in that The diene rubber is composed of 50-100 parts by mass of one or more of modified or unmodified styrene-butadiene copolymer rubber and polybutadiene rubber, and 0-50 parts by mass of one or more of modified or unmodified natural rubber and polyisoprene rubber.

5. The rubber composition according to claim 1, wherein The tetrazine compound is a combination of one or more of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3,6-bis(3-pyridyl)-1,2,4,5-tetrazine, and 3,6-bis(4-pyridyl)-1,2,4,5-tetrazine, and the tetrazine compound accounts for 0.3-1.2 parts by mass in the rubber composition.

6. The rubber composition according to claim 1, wherein The pyrazolone compound is a combination of one or more of 3-methyl-5-pyrazolone, 3-phenyl-5-pyrazolone, 3-ethyl-5-pyrazolone, 3-propyl-5-pyrazolone, and 3-butyl-5-pyrazolone, and the proportion of the pyrazolone compound in the rubber composition is 0.3-1.2 parts by mass.

7. The rubber composition according to claim 1, wherein The liquid rubber is a combination of one or more of modified or unmodified liquid polyisoprene, liquid hydrogenated polyisoprene, liquid polybutadiene, liquid styrene-isoprene copolymer, liquid isoprene-butadiene copolymer, and liquid styrene-butadiene copolymer, and the molecular weight of the liquid rubber is 500-100,000 g / mol, and the proportion of the liquid rubber in the rubber composition is 3-20 parts by mass.

8. The rubber composition according to claim 1, wherein The reinforcing filler is a combination of one or more of modified or unmodified carbon black, acetylene black, white carbon black, carbon nanotubes, graphite, and graphene; The silane coupling agent is a combination of one or more of bis-[3-(triethoxysilyl)propyl]-tetrasulfide, bis-[3-(triethoxysilyl)propyl]-disulfide, 3-octanoylthio-1-propyltriethoxysilane, γ-mercaptopropylethoxybis-(propyl-hexaethoxysiloxane), and mercaptoalkoxy-ethoxysilane.

9. The method for preparing the rubber composition according to any one of claims 1 to 8, wherein: The following steps are involved: Step (1) accurately weighing diene rubber, tetrazine compound, pyrazolone compound, liquid rubber, reinforcing filler, silane coupling agent, vulcanization accelerator, vulcanizing agent, antioxidant, vulcanization activator, resin and plasticizer; Step (2) mixing a portion of the diene rubber, the tetrazine compound, the antioxidant and the reinforcing filler, and subjecting the mixture to a mixing reaction at 120-180° C. for 60-300 seconds, and then cooling the mixture to obtain a material A, wherein the discharge temperature is 120-180° C.; Step (3) mixing the remaining diene rubber, pyrazolone compound, liquid rubber, silane coupling agent, vulcanization activator, resin and plasticizer with material A, and performing a mixing reaction at 120-180° C. for 60-300 seconds, and then cooling to obtain material B, wherein the discharge temperature is 120-180° C.; Step (4) adding a vulcanizing agent and a vulcanization accelerator to material B, mixing, and then discharging to obtain the rubber composition.

10. An OTR engineering tire, characterized in that: The rubber composition comprises the rubber composition according to any one of claims 1 to 8.

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