Modified styrene-butadiene rubber and its preparation method and application

Abstract

The present invention provides a modified styrene-butadiene rubber and a preparation method and application thereof. The preparation method comprises the following steps: S1, preparing a raw material liquid comprising a first part of styrene, butadiene, an emulsifier, a reducing agent and water, and adding an initiator to the raw material liquid to carry out an emulsion polymerization reaction; S2, when the reaction conversion rate reaches 10% to 12%, adding a second part of styrene to the emulsion polymerization reaction system and continuing the reaction, and when the reaction conversion rate reaches 60%, terminating the reaction to obtain a modified styrene-butadiene rubber. The preparation method of the present invention can achieve effective control of the weight content of styrene units and Mooney viscosity in the modified styrene-butadiene rubber, and promote the weight content of styrene units to reach 38-42% and the Mooney viscosity (ML 1+4 100℃ ) reaches 55-65, thereby greatly improving the cut resistance of the rubber, so that it can better meet the demand for rubber types used in engineering tires.

Description

Technical Field

[0001] The invention relates to the technical field of synthetic rubber production, and in particular to a modified styrene-butadiene rubber and a preparation method and application thereof. Background Art

[0002] In recent years, with the rapid development of my country's engineering machinery industry, the prosperity of the mining industry and the prosperity of urban engineering construction, engineering tires, as a wing of tires, have developed rapidly around the world, and the demand for engineering tires has also increased. It has become one of the fastest-growing and largest tire markets. Although the output of engineering tires accounts for 1% of the total tire output, the rubber consumption can reach more than 15%, making it one of the industries with much higher added value than automobile tires. Engineering tires are low-speed tires, mainly operating in mining areas, where the environment is relatively complex. They will inevitably come into contact with various gravel and sharp ore blocks, which will cut and damage the tires, and easily cause the tire tread to collapse and fall off. Moreover, large agricultural tires are mainly equipped with high-horsepower tractors. In actual use, due to the root stubble of crops left after harvesting in the cultivated land, the tires will inevitably suffer punctures and punctures. Therefore, to improve the quality of engineering mining tires and large agricultural tires, the focus is to improve the cutting and puncture resistance of tires.

[0003] Patent CN201810026700.6 relates to a tire-based rubber composition specifically for engineering machinery tires. The raw materials are based on 100 parts by weight of natural rubber, and also include 35 to 45 parts by weight of carbon black N330, 0 to 6 parts by weight of white carbon black, 1.0 to 3.0 parts by weight of stearic acid, 2.0 to 5.0 parts by weight of zinc oxide, 0.7 to 1.0 parts by weight of N-tert-butyl-2-benzothiazole sulfonamide, 1.5 to 2.5 parts by weight of sulfur, 0.5 to 1.0 parts by weight of antioxidant 4020, and 0.5 to 1.5 parts by weight of antioxidant RD. Patent CN200820026043.7 discloses a deep-patterned, highly puncture-resistant and cut-resistant bias giant engineering tire, comprising a carcass composed of multiple layers of high-strength fiber cords, a tread composed of tread rubber fixed to the outside of the carcass, and several layers of steel wire buffer layers composed of steel cords between the tread and the carcass, which increases the crown strength and absorbs the impact force of the tire on the ground, and can also increase the adhesion between the tread rubber and the carcass, effectively improving the tire's puncture resistance and puncture resistance to sharp objects. In summary, most of the research on engineering tires at home and abroad focuses on improving the tire's cut resistance and puncture resistance by developing and processing application formulas, while very few studies have been conducted on the modification of rubber materials.

[0004] As one of the important synthetic rubber (SR) varieties, styrene butadiene rubber (SBR) is currently the most produced and consumed general-purpose synthetic rubber in the world. In particular, styrene butadiene rubber can be widely used in the manufacture of engineering tires due to its excellent mechanical properties. However, in the prior art, when styrene butadiene rubber is used in the field of engineering tires, its cut resistance is poor and cannot meet the application requirements of engineering tire rubber materials. Summary of the invention

[0005] The main purpose of the present invention is to provide a modified styrene-butadiene rubber and a preparation method and application thereof, so as to solve the problem of poor cut resistance of styrene-butadiene rubber in the prior art when it is used in the field of engineering tires.

[0006] In order to achieve the above-mentioned object, according to one aspect of the present invention, a method for preparing modified styrene-butadiene rubber is provided. The preparation method comprises the following steps: S1, preparing a raw material liquid including a first part of styrene, butadiene, an emulsifier, a reducing agent, and water, and adding an initiator to the raw material liquid for emulsion polymerization; wherein, by weight, the raw material liquid comprises 40 to 47 parts of the first part of styrene, 48 to 56 parts of butadiene, 4.0 to 5.5 parts of an emulsifier, 0.065 to 0.085 parts of a reducing agent, and 180 to 200 parts of water, and the weight of the initiator is 0.06 to 0.12 parts; S2, when the reaction conversion rate reaches 10% to 12%, adding the second part of styrene to the reaction system of the emulsion polymerization and continuing the reaction, and when the reaction conversion rate reaches 60%, terminating the reaction, and then obtaining the modified styrene-butadiene rubber.

[0007] Furthermore, the weight ratio of the second part of styrene to the first part of styrene is 1:(3-6).

[0008] Furthermore, the raw material liquid includes, by weight, 42 to 45 parts of styrene, 50 to 54 parts of butadiene, 4.5 to 5.0 parts of emulsifier, 0.065 to 0.085 parts of reducing agent, and 180 to 200 parts of water; and the weight portion of the initiator is 0.06 to 0.12 parts.

[0009] Furthermore, the raw material solution further comprises, by weight, 0.07 to 0.15 parts of a molecular weight regulator and 0.63 to 1.03 parts of an electrolyte.

[0010] Furthermore, step S1 includes: vacuuming and nitrogen replacing the polymerization kettle, adding various raw materials into the polymerization kettle to form a raw material liquid, reducing the temperature in the polymerization kettle to below 5°C, and then adding an initiator to the raw material liquid to carry out an emulsion polymerization reaction. Step S2 includes: when the reaction conversion rate reaches 60%, adding a terminator to the polymerization kettle to terminate the reaction to obtain a polymerized rubber liquid; adding the polymerized rubber liquid into a dilute sulfuric acid solution for coagulation, washing, and drying to obtain a modified styrene-butadiene rubber.

[0011] Furthermore, the emulsifier is disproportionate rosin acid potassium soap and / or fatty acid sodium soap.

[0012] Preferably, the initiator is p-menthane hydroperoxide and / or diisopropylbenzene hydroperoxide.

[0013] Preferably, the reducing agent includes one or more of ferrous sulfate, sodium formaldehyde sulfoxylate and ethylenediaminetetraacetic acid tetrasodium salt; preferably, the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and ethylenediaminetetraacetic acid tetrasodium salt, and the weight ratio between the three is 1:(3-5):2.5.

[0014] Furthermore, the molecular weight regulator is tert-dodecyl mercaptan and / or n-dodecyl mercaptan.

[0015] Preferably, the electrolyte includes one or more of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate; preferably, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio between the four is (20-30):(30-50):3:(10-20).

[0016] Furthermore, the terminator is isopropylhydroxylamine and / or sulfate; preferably, the amount of the terminator is 0.055% to 0.150% by weight of the emulsifier.

[0017] According to another aspect of the present invention, a modified styrene-butadiene rubber is provided. The modified styrene-butadiene rubber is prepared by the above-mentioned preparation method.

[0018] Furthermore, the weight content of styrene units in the modified styrene butadiene rubber is 38% to 42%; and the Mooney viscosity of the modified styrene butadiene rubber is 55 to 65.

[0019] According to another aspect of the present invention, there is provided a use of the modified styrene-butadiene rubber prepared by the above preparation method as a material for manufacturing engineering tires.

[0020] The preparation method of the present invention can effectively control the weight content of styrene units and Mooney viscosity in the modified styrene-butadiene rubber, so that the weight content of styrene units reaches 38-42% and the Mooney viscosity (ML 1+4 100℃ ) reaches 55-65, thereby greatly improving the cut resistance of the rubber, so that it can better meet the demand for rubber types used in engineering tires. DETAILED DESCRIPTION

[0021] It should be noted that, in the absence of conflict, the embodiments and features in the embodiments of the present application can be combined with each other. The present invention will be described in detail below in conjunction with the embodiments.

[0022] As described in the background technology section, the existing technology of styrene-butadiene rubber has poor cut resistance when applied to the field of engineering tire manufacturing. In order to solve this problem, the present invention provides a method for preparing modified styrene-butadiene rubber, which comprises the following steps: S1, preparing a raw material liquid including a first part of styrene, butadiene, an emulsifier, a reducing agent, and water, and adding an initiator to the raw material liquid for emulsion polymerization. S2, when the reaction conversion rate reaches 10% to 12%, adding the second part of styrene to the emulsion polymerization reaction system and continuing the reaction, when the reaction conversion rate reaches 60%, terminating the reaction, and then obtaining modified styrene-butadiene rubber. Wherein, by weight, the raw material liquid includes 40 to 47 parts of the first part of styrene, 48 to 56 parts of butadiene, 4.0 to 5.5 parts of emulsifier, 0.065 to 0.085 parts of reducing agent, 180 to 200 parts of water, and the weight of the initiator is 0.06 to 0.12 parts.

[0023] The present invention controls the amount of each component in the raw material liquid within the above range, which can better exert the synergistic effect of each component, and promote the weight content of styrene units in the modified styrene-butadiene rubber to be more suitable, reaching 38% to 42%. In particular, the present invention first adds a part of styrene and butadiene to carry out emulsion polymerization, and when the reaction conversion rate reaches 10% to 12%, the second part of styrene is added to the emulsion polymerization reaction system and the reaction is continued until the conversion rate reaches 60% to terminate the reaction. Such operation can control the viscosity of the polymerization system at a more suitable Mooney viscosity level. The Mooney viscosity (ML 1+4 100℃ ) reaches 55 to 65. The above two reasons realize the controllability of the weight content of styrene units in the modified styrene butadiene rubber and the Mooney viscosity of the modified styrene butadiene rubber, and finally effectively improve the cut resistance of the styrene butadiene rubber. At the same time, the above method provided by the present invention has a more stable emulsion polymerization reaction, which is conducive to making the preparation process of the modified styrene butadiene rubber more stable, and the prepared modified styrene butadiene rubber has more uniform performance, and has the comprehensive advantages of other styrene butadiene rubbers in addition to better cut resistance.

[0024] In summary, the weight content of styrene units in the modified styrene butadiene rubber obtained by the preparation method of the present invention is 38% to 42%, the Mooney viscosity of the modified styrene butadiene rubber is 55 to 65, and the cut resistance is improved by more than 25% compared with the traditional styrene butadiene rubber, which is an ideal rubber for engineering tires.

[0025] Preferably, the weight ratio of the second part of styrene to the first part of styrene is 1:(3-6). Within this range, the viscosity of the polymerization system can be further controlled at a more suitable viscosity level, which promotes better stability of the polymerization reaction, and further can more effectively control the weight content of the styrene unit in the modified styrene butadiene rubber and the Mooney viscosity of the modified styrene butadiene rubber, thereby preparing a modified styrene butadiene rubber with better cut resistance.

[0026] In a preferred embodiment, the raw material liquid includes 42-45 parts of styrene, 50-54 parts of butadiene, 4.5-5.0 parts of emulsifier, 0.065-0.085 parts of reducing agent, 180-200 parts of water; and the weight part of the initiator is 0.06-0.12 parts. Within this range, the synergistic effect of each component is better, further promoting the weight content of styrene units in the modified styrene-butadiene rubber to be better, and the Mooney viscosity of the modified styrene-butadiene rubber to be better, thereby further improving the cut resistance of the modified styrene-butadiene rubber.

[0027] Preferably, step S1 includes: vacuuming and nitrogen replacing the polymerization kettle, adding various raw materials into the polymerization kettle to form a raw material liquid, reducing the temperature in the polymerization kettle to below 5°C, and then adding an initiator to the raw material liquid to carry out an emulsion polymerization reaction. Such operation can promote the homogenization of the raw material liquid before adding the initiator for polymerization, which is beneficial to maintaining the stability of the polymerization reaction. Step S2 includes: when the reaction conversion rate reaches 60%, adding a terminator to the polymerization kettle to terminate the reaction and obtain a polymerized glue. The polymerized glue is added to a dilute sulfuric acid solution for coagulation, washing, and drying to obtain a modified styrene-butadiene rubber. Specifically, the polymerized glue is added to a dilute sulfuric acid solution with a concentration of 0.5%, stirred, and the temperature is controlled at 60°C for coagulation, which can promote a more complete coagulation of the polymerized glue and obtain a more uniform performance of the modified styrene-butadiene rubber.

[0028] Based on the purpose of making the polymerization reaction more stable and the reaction efficiency higher. The preferred emulsifier is disproportionated potassium rosinate soap and / or fatty acid sodium soap. The preferred initiator is p-menthane hydroperoxide and / or diisopropylbenzene hydroperoxide. The preferred reducing agent includes one or more of ferrous sulfate, sodium formaldehyde sulfoxylate and ethylenediaminetetraacetic acid tetrasodium salt. More preferably, the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and ethylenediaminetetraacetic acid tetrasodium salt, and the weight ratio between the three is 1: (3 to 5): 2.5.

[0029] Preferably, the molecular weight regulator is tert-dodecyl mercaptan and / or n-dodecyl mercaptan. The molecular weight regulator selected from the above types can more effectively adjust the molecular weight of styrene-butadiene rubber, and can also more effectively control the weight content of styrene units in the modified styrene-butadiene rubber and the Mooney viscosity of the modified styrene-butadiene rubber during the polymerization reaction to be kept in a more suitable range, thereby further improving the cut resistance of the modified styrene-butadiene rubber. Preferably, the electrolyte includes one or more of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium meta-methylene dinaphthalene sulfonate. The electrolyte selected from the above types can be used in combination with the molecular weight regulator to control the viscosity of the reaction system, and is also beneficial to improve the conversion rate of the polymerization. More preferably, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium meta-methylene dinaphthalene sulfonate, and the weight ratio between the four is (20-30): (30-50): 3: (10-20).

[0030] Preferably, the raw material solution further comprises 0.07-0.15 parts of a molecular weight regulator and 0.63-1.03 parts of an electrolyte by weight. In this way, the molecular weight regulator has a better control effect on the weight content of styrene units and Mooney viscosity in the modified styrene-butadiene rubber during the polymerization reaction. At the same time, the synergistic effect of the molecular weight regulator and the electrolyte is better, and the effect of controlling the viscosity of the reaction system is better.

[0031] Preferably, the terminator is isopropylhydroxylamine and / or sulfate. The terminator is selected from the above types to terminate the polymerization reaction at a lower dosage. In a preferred embodiment, the amount of the terminator is 0.055% to 0.150% by weight of the emulsifier. The sulfate can be selected from conventional sodium persulfate in the art, etc., which can be selected by those skilled in the art, and will not be described in detail here.

[0032] The present invention also provides a modified styrene-butadiene rubber, which is prepared by the above-mentioned preparation method.

[0033] Based on the above reasons, the weight content of styrene units in the modified styrene butadiene rubber of the present invention is better, the Mooney viscosity of the modified styrene butadiene rubber is better, the weight content of styrene units in the modified styrene butadiene rubber is 38% to 42%; the Mooney viscosity of the modified styrene butadiene rubber is 55 to 65. The better weight content of styrene units and Mooney viscosity make the modified styrene butadiene rubber have better cut resistance.

[0034] The present invention also provides an application of the modified styrene-butadiene rubber as a material for manufacturing engineering tires.

[0035] Based on the above reasons, the cut resistance of the modified styrene-butadiene rubber of the present invention is improved by more than 25% compared with the traditional styrene-butadiene rubber, and is an ideal rubber for engineering tires.

[0036] The present application is further described in detail below in conjunction with specific embodiments. These embodiments should not be construed as limiting the scope of protection claimed in the present application.

[0037] Example 1

[0038] The polymerization kettle is vacuumed and replaced with nitrogen. By weight, 42 parts of the first part of styrene, 54 parts of butadiene, 4.5 parts of emulsifier potassium disproportionate rosin acid soap, 0.63 parts of electrolyte, 0.065 parts of reducing agent, 0.10 parts of tert-dodecyl mercaptan, and 190 parts of water are added to the polymerization kettle in sequence. When the temperature of the polymerization kettle drops to 5°C, 0.065 parts of initiator hydroperoxide p-menane are added to carry out polymerization reaction. When the conversion rate reaches 10%, the second part of styrene (the weight ratio of the second part of styrene to the first part of styrene is 1:3) is added and the reaction is continued. When the reaction conversion rate reaches 60%, the terminator isopropylhydroxylamine (the amount is 0.11% of the weight of the emulsifier) ​​is added to terminate the reaction to obtain a polymerized glue. The above polymerized glue is added to a 0.5% dilute sulfuric acid solution, stirred, and the temperature is controlled at 60°C for condensation, followed by washing and drying to obtain a modified styrene-butadiene rubber.

[0039] Among them, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio between the four is 20:30:3:10; the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetic acid, and the weight ratio between the three is 1:3:2.5.

[0040] Example 2

[0041] The polymerization kettle is vacuumed and replaced with nitrogen. By weight, 43 parts of the first part of styrene, 52 parts of butadiene, 4.65 parts of emulsifier potassium disproportionated rosin acid soap, 1.03 parts of electrolyte, 0.065 parts of reducing agent, 0.10 parts of tert-dodecyl mercaptan, and 190 parts of water are added to the polymerization kettle in sequence. When the temperature of the polymerization kettle drops to 5°C, 0.065 parts of initiator hydroperoxide p-menane are added to carry out polymerization reaction. When the conversion rate reaches 11%, the second part of styrene (the weight ratio of the second part of styrene to the first part of styrene is 1:5) is added and the reaction is continued. When the reaction conversion rate reaches 60%, the terminator isopropylhydroxylamine (the amount is 0.129% of the weight of the emulsifier) ​​is added to terminate the reaction to obtain a polymerized glue. The above polymerized glue is added to a 0.5% dilute sulfuric acid solution, stirred, and the temperature is controlled at 60°C for condensation, followed by washing and drying to obtain a modified styrene-butadiene rubber.

[0042] Among them, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio among the four is 30:50:3:20; the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetic acid, and the weight ratio among the three is 1:3:2.5.

[0043] Example 3

[0044] The polymerization kettle is vacuumed and replaced with nitrogen. By weight, 45 parts of the first part of styrene, 50 parts of butadiene, 4.55 parts of emulsifier potassium disproportionated rosin acid soap, 0.83 parts of electrolyte, 0.065 parts of reducing agent, 0.10 parts of tert-dodecyl mercaptan, and 190 parts of water are added to the polymerization kettle in sequence. When the temperature of the polymerization kettle drops to 5°C, 0.065 parts of initiator hydroperoxide p-menane are added to carry out polymerization reaction. When the conversion rate reaches 12%, the second part of styrene (the weight ratio of the second part of styrene to the first part of styrene is 1:6) is added and the reaction is continued. When the reaction conversion rate reaches 60%, the terminator isopropylhydroxylamine (the amount is 0.110% of the weight of the emulsifier) ​​is added to terminate the reaction to obtain a polymerized glue. The above polymerized glue is added to a dilute sulfuric acid solution with a concentration of 0.5%, stirred, and the temperature is controlled at 60°C for condensation, followed by washing and drying to obtain a modified styrene-butadiene rubber.

[0045] Among them, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio among the four is 25:35:3:20; the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetic acid, and the weight ratio among the three is 1:3:2.5.

[0046] Example 4

[0047] The only difference from Example 1 is that the weight portion of styrene in the first part is 40 parts.

[0048] Example 5

[0049] The only difference from Example 1 is that the weight portion of styrene in the first part is 47 parts.

[0050] Example 6

[0051] The only difference from Example 1 is the amount of the second part of styrene. The weight ratio of the second part of styrene to the first part of styrene is 1:8.

[0052] Comparative Example 1

[0053] The polymerization kettle is vacuumed and replaced with nitrogen. By weight, 35 parts of the first part of styrene, 40 parts of butadiene, 3.55 parts of emulsifier potassium disproportionate rosin acid soap, 0.83 parts of electrolyte, 0.055 parts of reducing agent, 0.04 parts of tert-dodecyl mercaptan, and 190 parts of water are added to the polymerization kettle in sequence. When the temperature of the polymerization kettle drops to 5°C, 0.045 parts of initiator hydroperoxide p-menane are added to carry out polymerization reaction. When the conversion rate reaches 30%, the second part of styrene (the weight ratio of the second part of styrene to the first part of styrene is 1:6) is added and the reaction is continued. When the reaction conversion rate reaches 60%, the terminator isopropylhydroxylamine (the amount is 0.141% of the weight of the emulsifier) ​​is added to terminate the reaction to obtain a polymerized glue. The above polymerized glue is added to a dilute sulfuric acid solution with a concentration of 0.5%, stirred, and the temperature is controlled at 60°C for condensation, followed by washing and drying to obtain a styrene-butadiene rubber sample.

[0054] Among them, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio among the four is 25:35:3:20; the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetic acid, and the weight ratio among the three is 1:3:2.5.

[0055] Comparative Example 2

[0056] The polymerization kettle was vacuumed and replaced with nitrogen. By weight, 46 parts of styrene, 54 parts of butadiene, 4.5 parts of potassium disproportionated rosin acid soap, 0.63 parts of electrolyte, 0.065 parts of reducing agent, 0.10 parts of tert-dodecyl mercaptan, and 190 parts of water were directly added to the polymerization kettle. When the temperature of the polymerization kettle dropped to 5° C., 0.065 parts of initiator p-menane hydroperoxide were added to carry out polymerization experiments. When the conversion rate reached 60%, the terminator isopropylhydroxylamine (the amount was 0.111% of the weight of the emulsifier) ​​was added to terminate the reaction to obtain a polymerized glue. The above polymerized glue was added to a 0.5% dilute sulfuric acid solution, stirred, and the temperature was controlled at 60° C. After condensation, it was washed and dried to obtain a styrene-butadiene rubber sample.

[0057] Among them, the electrolyte includes phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio among the four is 25:35:3:20; the reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and tetrasodium ethylenediaminetetraacetic acid, and the weight ratio among the three is 1:3:2.5.

[0058] Comparative Example 3

[0059] Traditional styrene butadiene rubber SBR1500E.

[0060] Performance Test:

[0061] The preparation and performance testing of rubber mixes and vulcanized rubber shall refer to GB 8655-2006.

[0062] The styrene butadiene rubber cutting test is a test of the cutting resistance of vulcanized styrene butadiene rubber and elastic materials. The instrument model is the GT-7012-Q rubber dynamic cutting resistance tester of the high-speed rail company. The cutter cuts the sample at a certain tilt angle and a certain load, and measures the volume or cutting index of the sample cut within a certain mileage. The cutting resistance of each styrene butadiene rubber is characterized by detecting the weight loss of each styrene butadiene rubber after the cutting test in the embodiments and comparative examples. The smaller the weight loss percentage of the styrene butadiene rubber, the better the cutting resistance. The test results are shown in Table 1 below:

[0063] Table 1

[0064]

[0065] The above are only preferred embodiments of the present invention and are not intended to limit the present invention. For those skilled in the art, the present invention may have various modifications and variations. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for preparing modified styrene-butadiene rubber, characterized in that: The preparation method The following steps are involved: S1, preparing a raw material liquid including a first part of styrene, butadiene, an emulsifier, an electrolyte, a reducing agent, a molecular weight regulator, and water, and adding an initiator to the raw material liquid for emulsion polymerization; wherein, in parts by weight, the raw material liquid includes 40 to 47 parts of the first part of styrene, 48 to 56 parts of the butadiene, 4.0 to 5.5 parts of the emulsifier, 0.63 to 1.03 parts of the electrolyte, 0.065 to 0.085 parts of the reducing agent, 0.07 to 0.15 parts of the molecular weight regulator, 180 to 200 parts of the water, and the weight of the initiator is 0.06 to 0.12 parts; S2, when the reaction conversion rate reaches 10% to 12%, adding a second portion of styrene to the emulsion polymerization reaction system and continuing the reaction, and when the reaction conversion rate reaches 60%, terminating the reaction to obtain the modified styrene-butadiene rubber; The weight ratio of the second part of styrene to the first part of styrene is 1:(3-6).

2. The method for preparing modified styrene-butadiene rubber according to claim 1, characterized in that: In parts by weight, the raw material liquid includes 42 to 45 parts of the first part of styrene, 50 to 54 parts of butadiene, 4.5 to 5.0 parts of the emulsifier, 0.63 to 1.03 parts of the electrolyte, 0.065 to 0.085 parts of the reducing agent, 0.07 to 0.15 parts of the molecular weight regulator, 180 to 200 parts of water, and the weight portion of the initiator is 0.06 to 0.12 parts.

3. The method for preparing modified styrene-butadiene rubber according to claim 1, characterized in that: Step S1 comprises: vacuuming and nitrogen replacing the polymerization kettle, adding various raw materials into the polymerization kettle to form the raw material liquid, lowering the temperature in the polymerization kettle to below 5° C., and then adding the initiator into the raw material liquid to carry out the emulsion polymerization reaction; In step S2, when the reaction conversion rate reaches 60%, a terminator is added to the polymerization kettle to terminate the reaction to obtain a polymerized rubber solution; the polymerized rubber solution is added to a dilute sulfuric acid solution for coagulation, washing, and drying to obtain the modified styrene-butadiene rubber.

4. The method for preparing the modified styrene-butadiene rubber according to any one of claims 1 to 3, characterized in that: The emulsifier is disproportionate rosin acid potassium soap and / or fatty acid sodium soap.

5. The method for preparing a modified styrene-butadiene rubber according to any one of claims 1 to 3, characterized in that: The initiator is p-menthane hydroperoxide and / or diisopropylbenzene hydroperoxide.

6. The method for preparing the modified styrene-butadiene rubber according to any one of claims 1 to 3, characterized in that: The reducing agent includes ferrous sulfate, sodium formaldehyde sulfoxylate and ethylenediaminetetraacetic acid tetrasodium salt, and the weight ratio of the three is 1:(3-5):2.

5.

7. The method for preparing the modified styrene-butadiene rubber according to any one of claims 1 to 3, characterized in that: The molecular weight regulator is tert-dodecyl mercaptan and / or n-dodecyl mercaptan.

8. The method for preparing the modified styrene-butadiene rubber according to any one of claims 1 to 3, characterized in that: The electrolyte includes one or more of phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate.

9. The method for preparing modified styrene-butadiene rubber according to claim 8, characterized in that: The electrolyte comprises phosphoric acid, potassium hydroxide, tetrasodium ethylenediaminetetraacetic acid and sodium m-methylene dinaphthalene sulfonate, and the weight ratio of the four is (20-30): (30-50): 3: (10-20).

10. The method for preparing modified styrene-butadiene rubber according to claim 3, characterized in that: The terminator is isopropylhydroxylamine and / or sulfate.

11. The method for preparing modified styrene-butadiene rubber according to claim 10, characterized in that: The amount of the terminator used is 0.055% to 0.150% by weight of the emulsifier.

12. A modified styrene-butadiene rubber, characterized in that: The modified styrene-butadiene rubber is prepared by the preparation method described in any one of claims 1 to 11.

13. The modified styrene-butadiene rubber according to claim 12, characterized in that: The weight content of styrene units in the modified styrene butadiene rubber is 38% to 42%; the Mooney viscosity of the modified styrene butadiene rubber is 55 to 65.

14. Use of the modified styrene-butadiene rubber prepared by the preparation method according to any one of claims 1 to 11 as a material for manufacturing engineering tires.

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