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 engineering trucks are driving under harsh road conditions, the rubber of the tires is in a damaging environment such as heat, oxygen, fatigue, and cutting and tearing under high load and cyclic deformation. Reducing the heat generation of the tires and improving the anti-damage properties of the tires such as cut and tear resistance are the key to improving the service life of the tires. For the traditional method of changing the type of rubber or increasing the amount of white carbon black, there are often limitations in performance. Since low heat generation rubber materials require lower energy dissipation (hysteresis loss), and high cut and tear resistance under large deformation requires higher 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 often when improving one property, other properties are lost, which makes it difficult to improve the overall service life of the tire. In actual applications, rubber compositions based on styrene-butadiene rubber are used to improve cut and tear resistance under harsh road conditions, but their high heat generation will affect the service life; rubber compositions based on natural rubber are used to reduce heat generation and increase service life under non-harsh road conditions, but their poor cut resistance will also affect service life. Therefore, it is currently difficult to achieve both low heat generation and high cut and tear resistance at the same time.

[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 and carbon black, a rubber composition that can not only impart excellent low heat generation to the tire, but also impart excellent wear resistance to the tire can be provided. However, there is no description and example data description of the cut and tear resistance in these patent publications. In addition, by using the rubber composition of the invention to make a tire, not only the rolling resistance of the tire can be reduced, and the heat generation of the tire can be reduced, but also the wear resistance can be improved, so that a low fuel consumption tire for large vehicles can be provided. However, wear resistance belongs to 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 contradictory to the rubber action mechanism of cut and tear resistance under large deformation under harsh road conditions. Therefore, the anti-destructive properties such as cut resistance and tear resistance of the tire made of the rubber composition are weak or even deteriorate, and 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, and an additive represented by general formula (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 the embodiment where the amount of natural rubber (NR) or polyisoprene rubber (IR) is 100 parts or more than 50 parts, the pyrazolone compound has good low heat generation, tear strength and durability; but there is no embodiment data showing that when the amount of synthetic rubber such as styrene-butadiene rubber (SBR) exceeds 50 parts, low heat generation, tear strength and durability are improved at the same time. Since the reaction activity of pyrazolone compounds with natural rubber is higher than that of synthetic rubber such as styrene-butadiene rubber, pyrazolone compounds can achieve good low heat generation and tear strength in a rubber composition mainly composed of natural rubber (in an amount exceeding 50 parts), but low heat generation and high tear strength cannot be achieved simultaneously in a rubber composition mainly 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 deteriorated, and cannot meet the use requirements of OTR engineering tires under harsh road conditions.

[0005] Therefore, how to provide a rubber composition and a preparation method thereof that can reduce heat generation and improve anti-damage performance is a technical problem that those skilled in the art need to solve urgently. 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 for reducing heat generation and improving damage resistance of OTR engineering tires in order to solve the problems existing in the prior art.

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

[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, and the proportions of the tetrazine compounds and the liquid rubber are not zero at the same time; 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 can be connected to form an alkylene group, and any two of R2, R3, and R4 can be connected 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 the groups each independently may 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 compounds, 0.2-1.5 parts of pyrazolone compounds, 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 compounds, 0.2-1.5 parts of pyrazolone compounds, 1-30 parts of liquid rubber, 20-100 parts of reinforcing fillers, 0-5 parts of silane coupling agents, and 2-10 parts of vulcanization activators.

[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 compounds, 0.2-1.5 parts of pyrazolone compounds, 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 produce 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 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 addition of liquid rubber containing special functional groups alone has a certain effect of improving anti-destruction, 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 tires.

[0024] Furthermore, the rubber composition also includes 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-benzothiazole sulfenamide. 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, in the present invention, antioxidant 6PPD, dicyclopentadiene DCPD resin and plasticizer are selected.

[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-damage performance.

[0034] Considering that emulsion polybutadiene styrene rubber has high molecular weight and strong anti-destruction ability, in some embodiments, emulsion polybutadiene styrene 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, and 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 proportion 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, and more preferably 3-methyl-5-pyrazolone. The proportion of the pyrazolone compound in the rubber composition is preferably 0.3-1 parts by mass, and more preferably 0.3-0.8 parts by mass.

[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 500-100000 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, and carboxylic acid acrylate-modified liquid polybutadiene, and is further preferably a combination of one or more of maleic anhydride-modified liquid polyisoprene and carboxylic acid acrylate-modified liquid polyisoprene. The molecular weight of the liquid rubber is preferably 500-80000 g / mol, and is further preferably 500-50000 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 adopts the above-mentioned tetrazine compounds and pyrazolone compounds to graft-modify styrene-butadiene rubber and natural rubber, thereby improving the dispersion of fillers, reducing heat generation, and improving the anti-destruction performance of the final product. After the liquid rubber is added, it has a synergistic effect with the tetrazine compounds and pyrazolone compounds, further reducing heat generation and improving anti-destruction performance such as cut resistance and tear resistance.

[0043] Further, 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 is 60-250m 2 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 above 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 is further 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 part of the diene rubber, the tetrazine compound, the antioxidant and the reinforcing filler, and performing a mixing reaction at 120-180° C. for 60-300 seconds, and cooling the mixture to obtain 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 cooling the mixture 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) or 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 may be added in step (2) or step (3); part or all of the white carbon black in the reinforcing filler may be added in step (2) or step (3); and part or all of the silane coupling agent may 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 conforms to 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-destruction properties such as cut resistance and tear resistance; the preparation method of the present invention is simple to operate and has strong practicality.

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

[0064] An OTR engineering tire comprises the rubber composition as 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 drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only embodiments of the present invention. For ordinary technicians in this field, 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 technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0069] The word "embodiment" used here as an "exemplary" does not necessarily mean that any embodiment described is superior to or better than other embodiments. Unless otherwise specified, the performance index tests in the embodiments of this application are performed using conventional test methods in the art. It should be understood that the terms described in this application are only used to describe specific implementation methods and are not used to limit the content disclosed in this application.

[0070] Unless otherwise specified, the technical and scientific terms used in this document 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 the present application, numerous specific details are provided in the specific examples below. It should be understood by those skilled in the art that the present application can also be implemented without certain specific details. In the embodiments, 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 the present application.

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

[0073] The present invention provides a rubber composition and a preparation method thereof, and an OTR tire using the same. The rubber composition (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. And 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 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 technicians in this field according to the above invention content are also considered to fall within the protection scope 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, the test condition is ML (1+4) 100°C. The larger the index, the higher the Mooney viscosity.

[0077] 2) Mooney scorch: Refer to ASTM D1646-2007, the 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, refer to ASTM D412-2006, take the modulus when the elongation is 100%, 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, the sample is dumbbell-shaped, the test speed is 500mm / min, and the test environment temperature is 23±2°C. The larger the index, the higher the tensile strength.

[0081] 6) Hysteresis loss factor: Tested using Metravib DMA, temperature 60°C, frequency 10 Hz, dynamic deformation 0.07%-50%, plane shear mode. The smaller the index, the smaller the hysteresis loss, the lower the rolling resistance and heat generation.

[0082] 7) High temperature slow tearing energy: Use a sample with a width of 40 mm, a height of 65 mm, and a notch of 10 mm (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: striking frequency 120 / min; rubber wheel speed 720rpm; Test method: The mass of the rubber wheel after 5 minutes of pre-cutting is recorded as m0, and the mass after 20 minutes of cutting is recorded as m1; Data recording cutting loss mass per minute: Δm=(m 0 -m 1 ) / 15min; the smaller the index is, the smaller the cutting quality loss is, and the better the cutting and tearing resistance is.

[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, TCI (Shanghai) Chemical Industry Development Co., Ltd.

[0090] Liquid rubber: Carboxylic acid acrylate modified liquid polyisoprene, 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 in mass fractions. Among them, Examples 1-1 to 1-5 are rubber compositions in which 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone are used in combination. Comparative Examples 1-2 and 1-3 are rubber compositions in which 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone are used separately.

[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 compounds, 10 parts of carbon black N220 and antioxidant 6PPD, mixing and reacting at 130-150°C for 150 seconds, and discharging at 150°C to obtain material A; step (3) mixing the remaining raw materials except the vulcanizing agent and the vulcanization accelerator with material A, mixing and reacting at 140-160°C for 150 seconds, and discharging at 160°C to obtain material B; step (4) adding the vulcanizing agent and the vulcanization accelerator to material B, mixing in an internal mixer for about 180 seconds, and discharging at 110°C to obtain a rubber composition for reducing heat generation of OTR engineering tires while improving anti-destruction performance. Then the obtained rubber composition is 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, 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=(embodiment / comparative example 1-1)×100.

[0113] Compared with comparative example 1-1, in the case of little change in hardness, the tensile strength of examples 1-1 to 1-5 decreased, the elongation at break increased slightly, the slow tearing at 100°C increased by 20-40%, the hysteresis loss decreased by 17-24%, and the cutting loss decreased by 12-19%. The cutting loss of comparative example 1-2 decreased by 25%, the slow tearing at high temperature increased by 50%, but the hysteresis loss deteriorated. Similarly, the hysteresis loss of comparative example 1-3 decreased by 20%, the slow tearing at high temperature increased by 22%, but the cutting loss deteriorated by 7%. After 3 days of thermal 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, they can not only improve the anti-destructive performance (cutting resistance, tearing 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 mass fractions. Among them, Comparative Examples 2-2 and 2-3 are compositions to which different fractions of carboxylic acid acrylate modified liquid polyisoprene 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 to which 3-methyl-5-pyrazolone and carboxylic acid acrylate modified liquid polyisoprene are used in combination; Example 2-3 is a rubber composition to 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 to which three compounds of 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3-methyl-5-pyrazolone and carboxylic acid acrylate modified liquid polyisoprene are added 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] Step (1) weighing the raw materials according to the above weight; step (2) mixing SBR1502 and rubber for 30 seconds, adding tetrazine compounds, 10 parts of carbon black N220 and antioxidant 6PPD, mixing and reacting at 130-150°C for 150 seconds, and discharging at 150°C to obtain material A; step (3) mixing STR20, 3-methyl-5-pyrazolone, carboxylic acid acrylate modified liquid polyisoprene, and other remaining raw materials except vulcanizing agent and vulcanization accelerator with material A, mixing and reacting at 140-160°C for 150 seconds, and discharging at 160°C to obtain material B; step (4) adding vulcanizing agent and vulcanization accelerator to material B, mixing in an internal mixer for about 180 seconds, and discharging at 110°C to obtain a rubber composition for reducing heat generation of OTR engineering tires while improving anti-destruction performance. Then the obtained rubber composition is 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 respectively carried out before aging and after aging at 100° C. for 72 hours. 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]

[0124] *The test results of rubber compositions are expressed in the form of indices.

[0125] The calculation formula is: test item = (Example / Comparative Example 2-1) × 100.

[0126] Compared with comparative example 2-1, comparative examples 2-2, 2-3, and 2-4 have increased their high-temperature slow tearing energy by 19%, 21%, and 40%, respectively, and their cutting losses by 13%, 15%, and 14%, respectively, while the hardness has not changed much. The hysteresis loss has not changed much or has slightly increased. Among them, the elongation of examples 2-1 to 2-2 has increased by 39% and 49%, and the high-temperature slow tearing energy has increased by 400%-500%. After 3 days of thermal oxidation aging in a 100°C oven, the effect has still been greatly improved. The tensile strength of examples 2-3 and 2-4 has improved, the elongation at break has increased significantly, the high-temperature tearing energy has increased significantly by 36% and 47%, respectively, and the cutting loss has decreased by about 10-15%, and the hysteresis loss has also decreased by 18-16%. Therefore, the use of 3-methyl-5-pyrazolone and carboxylic acid acrylate modified liquid polyisoprene can significantly improve the anti-destructive performance of rubber when used in tires, and the heat generation is reduced to a certain extent. When 3-methyl-5-pyrazolone, 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and carboxylic acid acrylate modified polyisoprene are used together in tires, the anti-damage performance of rubber can be significantly improved and the heat generation can be significantly reduced.

[0127] Example 3

[0128] 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 in mass fractions. Among them, Examples 3-1 and 3-3 add 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine and 3-methyl-5-pyrazolone rubber compositions compared to Comparative Example 3-1; Examples 3-2 and 3-4 add 3,6-bis(2-pyridyl)-1,2,4,5-tetrazine, 3-methyl-5-pyrazolone and carboxylic acid acrylate modified liquid polyisoprene rubber compositions used in combination compared to Comparative Example 3-1.

[0129] Table 5: Formulas of Comparative Example 3-1 and Examples 3-1 to 3-4

[0130]

[0131] The above schemes all adopt the following preparation method:

[0132] Step (1) weighing the raw materials according to the above weight; step (2) mixing SBR1502 rubber for 30 seconds, adding tetrazine compounds, 10 parts of carbon black N220 and antioxidant 6PPD, mixing and reacting at 130-150°C for 150 seconds, and discharging at 150°C to obtain material A; step (3) mixing the remaining raw materials except the vulcanizing agent and the vulcanization accelerator with material A, mixing and reacting at 140-160°C for 120 seconds, and discharging at 160°C to obtain material B; step (4) adding the vulcanizing agent and the vulcanization accelerator to material B, mixing in an internal mixer for about 180 seconds, and discharging at 110°C to obtain a rubber composition for reducing heat generation of OTR engineering tires on harsh roads while improving anti-destruction performance. Then the obtained rubber composition is vulcanized at 150°C for 30 minutes for testing.

[0133] 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.

[0134] Table 6: Comparison of performance results of Examples 3-1 to 3-4 and Comparative Example 3-1

[0135]

[0136]

[0137] *The test results of rubber compositions are expressed in the form of indices.

[0138] The calculation formula is: test item = (Example / Comparative Example 3-1) × 100.

[0139] 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 become worse. 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 can both improve the anti-destructive performance of rubber and reduce heat generation when used in the formulation of this OTR engineering tire.

[0140] Compared with Examples 3-1 and 3-3, Examples 3-2 and 3-4 contain more carboxylic acid acrylate modified liquid polyisoprene, 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 carboxylic acid acrylate modified polyisoprene can significantly improve the anti-destruction performance of rubber and reduce heat generation when used in the OTR engineering tire formulation.

[0141] The above description of the disclosed embodiments enables one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be 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 will not be limited to the embodiments shown herein, but rather 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 weight: 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, and 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 can be connected to form an alkylene group, and any two of R2, R3, and R4 can be connected 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 the groups each independently may 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, characterized in that It also includes 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 weight of one or more of modified or unmodified styrene-butadiene copolymer rubber and polybutadiene rubber, and 0-50 parts by weight of one or more of modified or unmodified natural rubber and polyisoprene rubber.

5. The rubber composition according to claim 1, characterized in that 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, characterized in that 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, characterized in that 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 500-100000 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, characterized in that 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, characterized in that: 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 part of the diene rubber, the tetrazine compound, the antioxidant and the reinforcing filler, and performing a mixing reaction at 120-180° C. for 60-300 seconds, and cooling the mixture to obtain 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 cooling the mixture 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 for mixing and then discharging the mixture to obtain the rubber composition.

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

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