Epoxidized solution-polymerized styrene-butadiene rubber and its preparation method and application

Abstract

A method for preparing epoxidized solution-polymerized styrene-butadiene rubber (SPBR) utilizes hydrogen peroxide, formic acid, a surfactant, and SPBR as a reaction system. By controlling the ratio of hydrogen peroxide to formic acid to improve reaction efficiency, an epoxidized SPBR solution with an epoxidation degree of 3 to 30% is obtained. A carbonate solution is added to the solution to treat the solution to a pH of 7 to 10, resulting in a precipitated rubber. After drying, the epoxidized SPBR suitable for green tires is obtained. The preparation method provided by the present invention can more efficiently and cost-effectively prepare epoxidized SPBR, which is suitable for use as a tread rubber in green tires.

Description

Technical Field

[0001] The invention belongs to the technical field of rubber, and in particular relates to an epoxidized solution-polymerized styrene-butadiene rubber and a preparation method and application thereof. Background Art

[0002] In the 1990s, Michelin launched its first "green tire" product to reduce energy consumption and carbon dioxide emissions. Solution styrene butadiene rubber (SSBR) is widely used in green tire tread rubber due to its narrow molecular weight distribution, few branch ends, and excellent performance. However, SSBR is a non-polar rubber with poor affinity for silica, so SSBR needs to be functionalized. Epoxidation of the double bonds in SSBR is a good method to enhance the interaction between rubber and silica, promote silica dispersion, and thus improve anti-skid and wear resistance and reduce rolling resistance, thereby producing high-performance green tires.

[0003] Jacobi et al. (Kautschuk Gummi Kunststoffe, 2002, 55(11):590-595) established the conditions for the epoxidation reaction of SBR and showed that the epoxidation reaction depends largely on the concentration of hydrogen peroxide, reaction temperature and time. Cui Jinfeng et al. (Synthetic Rubber Industry, 2016, 39(3):203-207) used toluene and cyclopentane as solvents, respectively, to epoxidize solution-polymerized styrene-butadiene rubber by in-situ peroxyformic acid method and studied the conditions for the epoxidation reaction of SSBR. Chen Yong et al. (Synthetic Rubber Industry, 2006, 29(1):48-50) reported that polyethylene glycol as a phase transfer catalyst can improve the epoxidation degree of emulsion-polymerized styrene-butadiene rubber.

[0004] The aforementioned literature indicates that the peracid method, represented by hydrogen peroxide and formic acid, is one of the preferred methods for epoxidation due to its mild reaction conditions, water as a byproduct, and minimal environmental pollution. In situ generated performic acid facilitates epoxidation under mild reaction conditions.

[0005] CN104448060A discloses a method for preparing epoxidized solution-polymerized styrene-butadiene rubber. The amounts of formic acid and hydrogen peroxide used are 0.5 to 1.5 times the amount of the double-bond substance, respectively. The reaction temperature is 40 to 70° C., and the reaction time is 2 to 5 hours. After the reaction is completed, the epoxidized solution-polymerized styrene-butadiene rubber is washed with distilled water until it becomes neutral.

[0006] CN105985551A discloses a method for preparing an epoxidized solution rubber / silica composite material, wherein the molar ratio of hydrogen peroxide and formic acid to the solution rubber is 0.05-0.8, the reaction temperature is 40-70° C., and the reaction time is 1-2 hours.

[0007] CN109553833A discloses a method for preparing epoxidized solution-polymerized styrene-butadiene rubber. The solution-polymerized styrene-butadiene rubber is dissolved in n-hexane solution. After the reaction is completed, a saturated sodium bicarbonate solution is added for washing, and ethanol is added to precipitate the rubber.

[0008] CN109608653A discloses a method for preparing epoxidized solution-polymerized styrene-butadiene rubber, which comprises the following steps: the molar ratio of hydrogen peroxide: butadiene: formic acid is 3:2:1, the reaction temperature is 32-40°C, and the reaction is stirred for 1 hour.

[0009] CN111100343A discloses an automobile tire rubber material with excellent sound absorption performance and a preparation method thereof. After the reaction is completed, the rubber is washed with water until neutral, dried with anhydrous sodium sulfate, and then anhydrous ethanol is added. Solids are precipitated during the process of reduced pressure concentration.

[0010] Formic acid is difficult to completely remove from the system, and residual formic acid can lead to reduced performance of epoxidized solution-polymerized styrene-butadiene rubber (SPSB). During the post-treatment of epoxidized SPSB, large amounts of water washing are required to remove formic acid, and large amounts of ethanol are commonly used to separate the rubber from the solvent. Summary of the Invention

[0011] To address the above technical problems, the present invention proposes a highly efficient and low-cost method for preparing epoxy solution-polymerized styrene-butadiene rubber. The method employs the addition of a surfactant to increase the compatibility of the organic and aqueous phases, controls the ratio of hydrogen peroxide to solution-polymerized styrene-butadiene rubber to control the degree of epoxidation, and controls the ratio of hydrogen peroxide to formic acid to increase reaction efficiency. This method eliminates the need for water washing and alcohol precipitation, reducing costs.

[0012] One of the objects of the present invention is to provide a method for preparing an epoxidized solution-polymerized styrene-butadiene rubber, comprising the following steps:

[0013] The solution-polymerized styrene-butadiene rubber is added to a solvent to prepare a glue solution, formic acid and a surfactant are added, the mixture is stirred evenly, a hydrogen peroxide solution is added dropwise, and the mixture is heated for reaction to obtain an epoxidized solution-polymerized styrene-butadiene glue solution; a carbonate solution is added to the glue solution after the reaction to treat the mixture until the pH value is 7-10 to obtain a precipitated glue, and the epoxidized solution-polymerized styrene-butadiene rubber is obtained after drying.

[0014] Wherein, the molar ratio of hydrogen peroxide to formic acid is 0.4-2.5:1, preferably 0.4-1.5:1.

[0015] In the above preparation method, the molar ratio of hydrogen peroxide to double bonds in the solution-polymerized styrene-butadiene rubber is 0.01 to 0.5:1, preferably 0.04 to 0.4:1.

[0016] The solution polymerized styrene butadiene rubber used in the present invention can be the solution polymerized styrene butadiene rubber commonly used in the art, and can be pure solution polymerized styrene butadiene rubber or oil-containing solution polymerized styrene butadiene rubber. As long as the epoxidized solution polymerized styrene butadiene rubber can be obtained by the above reaction, it can be used in the present invention.

[0017] In the above preparation method,

[0018] The solvent is selected from at least one of cyclohexane and n-hexane, preferably cyclohexane, or a mixed solvent of cyclohexane and n-hexane;

[0019] The concentration of the glue solution is 5 to 20 g / 100 mL, preferably 8 to 15 g / 100 mL.

[0020] In the above preparation method,

[0021] The surfactant is selected from at least one of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants, and is preferably selected from at least one of sodium dodecylbenzenesulfonate, polysorbate, sorbitan fatty acid, polyethylene glycol, quaternary ammonium compounds, and sodium dodecylaminopropionate;

[0022] Based on 100 g of the solution-polymerized styrene-butadiene rubber, the added amount of the surfactant is 1 to 10 drops, preferably 3 to 8 drops.

[0023] In the above preparation method,

[0024] The hydrogen peroxide solution is added at a rate of 1 to 10 mL / min, preferably 4 to 8 mL / min;

[0025] The heating reaction temperature is 25-55°C, preferably 35-45°C;

[0026] The heating reaction time is 1 to 4 hours, preferably 2 to 4 hours.

[0027] In the above preparation method,

[0028] The carbonate is selected from at least one of lithium carbonate, ammonium carbonate, sodium carbonate, potassium carbonate, and basic carbonate, preferably selected from at least one of ammonium carbonate, sodium carbonate, and potassium carbonate;

[0029] The concentration of the sodium carbonate solution is 2 to 15 g / 100 mL, preferably 4 to 10 g / 100 mL;

[0030] The molar ratio of the carbonate to formic acid is 0.1 to 5:1, preferably 0.5 to 4:1;

[0031] The temperature for adding the carbonate solution is 25-60°C, preferably 30-50°C.

[0032] The present invention adopts the above-mentioned preparation method, selects the appropriate amount of sodium carbonate, and adjusts the pH of the system to 7-10. No water washing and alcohol precipitation are required, and the residual sodium carbonate can promote the vulcanization of the rubber composition, further improving the rubber performance. Therefore, the epoxidized solution-polymerized styrene-butadiene rubber provided by the present invention is beneficial to improving the performance of green tires.

[0033] A second object of the present invention is to provide an epoxidized solution-polymerized styrene-butadiene rubber prepared by the above-mentioned preparation method.

[0034] The epoxidized solution-polymerized styrene-butadiene rubber obtained by the above preparation method has an epoxidation degree of 3 to 30%, preferably 5 to 20%, and can be used in the production of green tires. The epoxidation degree is significantly affected by the ratio of hydrogen peroxide, styrene-butadiene rubber, and formic acid. The epoxidation degree of the epoxidized solution-polymerized styrene-butadiene rubber suitable for green tires falls within a certain range. A too low epoxidation degree fails to effectively improve silica dispersion, while a too high epoxidation degree degrades rubber performance, making it unsuitable for green tires.

[0035] A third object of the present invention is to apply the epoxidized solution-polymerized styrene-butadiene rubber obtained by the above-mentioned preparation method or the above-mentioned epoxidized solution-polymerized styrene-butadiene rubber to a rubber composition.

[0036] Currently, the amount of hydrogen peroxide and formic acid used is relatively high, resulting in incomplete reaction, low reaction efficiency, and numerous side reactions. This leads to a large amount of residual reactants after the reaction, which in turn increases production and post-processing costs. Extensive research has shown that under appropriate hydrogen peroxide and formic acid ratios, and under appropriate reaction temperatures and times, epoxidized solution-polymerized styrene-butadiene rubber suitable for green tires can be prepared.

[0037] The preparation method provided by the present invention has mild reaction conditions and is easy to carry out the epoxidation reaction. After using sodium carbonate to treat the residual formic acid in the system and adjusting the pH of the system to 7-10, the obtained precipitated glue can be directly dried without the need for water washing and alcohol precipitation processes, thereby reducing costs, reducing environmental pollution, and having broad application prospects. DETAILED DESCRIPTION

[0038] The present invention will be described in detail below with reference to specific embodiments. It is necessary to point out that the following embodiments are only used to further illustrate the present invention and are not to be construed as limiting the scope of protection of the present invention. Non-essential improvements and adjustments made by those skilled in the art to the present invention based on the contents of the present invention still fall within the scope of protection of the present invention.

[0039] The test instruments and test conditions used in the examples are as follows:

[0040] NMR spectrum analysis ( 1HNMR): The test equipment used was a Bruker AV400 with a frequency of 400 MHz. The sample was dissolved in deuterated chloroform (CDCl3) to prepare a solution of 11.3 mg / 0.6 mL.

[0041] Vulcanization Performance Test: Using the M-3000, 5-7g of the 24-hour-old rubber mix was cut into square or round pieces (smaller than the mold cavity). Cover the top and bottom ends with cellophane paper and test at 150°C for 60 minutes to determine the vulcanization time and torque parameters of the mix.

[0042] Example 1

[0043] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL sodium carbonate (3.95g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 1.

[0044] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a positive curing time test at 150°C and is designated as rubber 1*.

[0045] Example 2

[0046] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 4.8g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL sodium carbonate (5.53g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 2.

[0047] Example 3

[0048] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 8g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL sodium carbonate (9.2g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 3.

[0049] According to the formula, epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), white carbon black VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts) and sulfur (0.15 parts) were mixed to obtain a rubber compound. The rubber compound was subjected to a positive curing time test at 150°C and recorded as rubber 3*.

[0050] Example 4

[0051] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 12.41g of formic acid and 3 drops of Tween 80. After 10 minutes, add 5.52g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL sodium carbonate (14.29g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 4.

[0052] Example 5

[0053] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 15.07g of formic acid and 3 drops of Tween 80. After 10 minutes, add 6.71g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL sodium carbonate (17.37g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 5.

[0054] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), white carbon black VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The rubber compound was subjected to a positive curing time test at 150°C and was recorded as rubber 5*.

[0055] Example 6

[0056] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL ammonium carbonate (4.66g, with a molar ratio of ammonium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 6.

[0057] Example 7

[0058] Add 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, allow to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. Add an aqueous solution of 5g / 100mL potassium carbonate (4.25g, with a molar ratio of potassium carbonate to formic acid of 0.5:1) and stir at 25°C for one hour; the aqueous solution has a pH of 7. Dry in a 60°C forced air oven to obtain rubber 7.

[0059] Example 8

[0060] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40℃ water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) rubber solution. Add an aqueous solution of 5g / 100mL sodium carbonate (7.9g, with a molar ratio of sodium carbonate to formic acid of 1:1) and stir at 25℃ for one hour; the pH of the aqueous solution is 9. Place in a 60℃ forced air oven and dry to obtain rubber 8.

[0061] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a positive curing time test at 150°C and is designated as rubber 8*.

[0062] Example 9

[0063] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) rubber solution. Add an aqueous solution of 5g / 100mL sodium carbonate (15.8g, based on a molar ratio of potassium carbonate to formic acid of 2:1) and stir at 25°C for one hour; the aqueous solution has a pH of 10. Dry in a 60°C forced air oven to obtain rubber 9.

[0064] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a positive curing time test at 150°C and is designated as rubber 9*.

[0065] Example 10

[0066] 56.76 g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) was added to 350 mL of a 1:1 cyclohexane / n-hexane mixture. The mixture was stirred at 800 rpm in a 40°C water bath until completely dissolved. 3.4 g of formic acid and 3 drops of Tween 80 were added. After 10 minutes, 3.55 g of hydrogen peroxide was added dropwise at a rate of 5 ml / min. After the addition was complete, the mixture was allowed to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. An aqueous solution of 5 g / 100 mL of sodium carbonate (3.95 g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) was added and stirred at 25°C for one hour; the pH of the aqueous solution was 7. The mixture was dried in a 60°C forced air oven to obtain rubber 10.

[0067] Example 11

[0068] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40℃ water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of sodium dodecylbenzenesulfonate. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) rubber solution. Add an aqueous solution of 5g / 100mL sodium carbonate (3.95g, with a molar ratio of sodium carbonate to formic acid of 0.5:1) and stir at 25℃ for one hour; the pH of the aqueous solution is 7. Place in a 60℃ forced air oven for drying to obtain rubber 11.

[0069] Example 12

[0070] 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) was added to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. 3.4g of formic acid and 3 drops of Tween 80 were added. After 10 minutes, 3.55g of hydrogen peroxide was added dropwise at a rate of 5ml / min. After the addition was complete, the mixture was allowed to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. An aqueous solution of 5g / 100mL sodium carbonate (6.32g, with a molar ratio of sodium carbonate to formic acid of 0.8:1) was added and stirred at 25°C for one hour; the pH of the aqueous solution was 8. Drying was performed in a 60°C forced air oven to obtain rubber 12.

[0071] Comparative Example 1

[0072] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40℃ water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) glue. Add deionized water and stir at 25℃ for one hour, then remove the ionized water. Repeat several times, and then use ethanol to precipitate the rubber. Place the precipitated rubber in a 60℃ forced air oven for drying to obtain rubber 13.

[0073] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a positive curing time test at 150°C and is designated as rubber 13*.

[0074] Comparative Example 2

[0075] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40℃ water bath until completely dissolved. Add 15.07g of formic acid and 3 drops of Tween 80. After 10 minutes, add 6.71g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) glue. Add 195mL of saturated sodium carbonate aqueous solution and wash twice, add 195mL of water and wash twice, and then add 195mL of ethanol to precipitate the glue. Place the precipitated rubber in a 75℃ forced air oven for drying to obtain rubber 14.

[0076] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a positive curing time test at 150°C and is designated as rubber 14*.

[0077] Comparative Example 3

[0078] Take 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and a double bond molar weight of 0.58mol) and add it to 350mL of cyclohexane. Stir at 800rpm in a 40℃ water bath until completely dissolved. Add 3.4g of formic acid and 3 drops of Tween 80. After 10 minutes, add 3.55g of hydrogen peroxide at a rate of 5ml / min. After the addition is complete, react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) rubber solution. Add an aqueous solution of 5g / 100mL sodium bicarbonate (6.3g, with a molar ratio of sodium bicarbonate to formic acid of 1:1) and stir at 25℃ for one hour. Place in a 60℃ forced air oven for drying to obtain rubber 15.

[0079] A rubber compound was prepared by mixing epoxidized solution-polymerized styrene-butadiene rubber (13.75 parts), zinc oxide (0.3 parts), stearic acid (0.2 parts), silica VN3 (6 parts), accelerator CZ (0.2 parts), accelerator D (0.2 parts), antioxidant 4010NA (0.2 parts), paraffin wax (0.15 parts), and sulfur (0.15 parts). The compound was subjected to a vulcanization time test at 150°C and is designated as Rubber 15*.

[0080] Comparative Example 4

[0081] 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) was added to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. 13.34g of formic acid and 3 drops of Tween 80 were added. After 10 minutes, 9.86g of hydrogen peroxide was added dropwise at a rate of 5ml / min. After the addition was complete, the mixture was allowed to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. An aqueous solution of 5g / 100mL sodium bicarbonate (15.4g, with a molar ratio of sodium bicarbonate to formic acid of 0.5:1) was added and stirred at 25°C for one hour; the aqueous solution had a pH of 7. Drying was performed in a 60°C forced air oven to obtain rubber 16.

[0082] Comparative Example 5

[0083] 56.76g of commercially available solution-polymerized styrene-butadiene rubber (SSBR, containing 27% oil and 0.58 mol of double bonds) was added to 350mL of cyclohexane. Stir at 800rpm in a 40°C water bath until completely dissolved. 13.4g of formic acid and 3 drops of Tween 80 were added. After 10 minutes, 98.6g of hydrogen peroxide was added dropwise at a rate of 5ml / min. After the addition was complete, the mixture was allowed to react for four hours to obtain an epoxidized solution-polymerized styrene-butadiene rubber (ESSBR) solution. An aqueous solution of 5g / 100mL sodium bicarbonate (6.3g, with a molar ratio of sodium bicarbonate to formic acid of 0.5:1) was added and stirred at 25°C for one hour; the pH of the aqueous solution was 7. Drying was performed in a 60°C forced air oven to obtain rubber 17.

[0084] Analysis of the epoxidized solution-polymerized butadiene styrene obtained in the examples and comparative examples

[0085] Table 1 shows the epoxy degree of Examples 1 to 12 and Comparative Examples 1 to 5.

[0086] Table 1. Epoxy Degrees of Examples 1 to 12 and Comparative Examples 1 to 5

[0087] Epoxy degree (%) Example 1 9.2 Example 2 11.7 Example 3 14.6 Example 4 23.2 Example 5 28.3 Example 6 9.2 Example 7 9.2 Example 8 9.2 Example 9 9.2 Example 10 9.1 Example 11 9.1 Example 12 9.2 Comparative Example 1 9.2 Comparative Example 2 28.3 Comparative Example 3 9.2 Comparative Example 4 7.3 Comparative Example 5 32

[0088] As shown in Table 1, Examples 1-3 demonstrate that increasing the amount of formic acid is beneficial for increasing the epoxidation degree, indicating that a smaller molar ratio of hydrogen peroxide to formic acid can achieve higher epoxidation degrees and improve reactant utilization. Examples 4-5, compared to Example 1, illustrate the effect of varying hydrogen peroxide to double bond ratios on epoxidation degrees. In Comparative Examples 4 and 5, reactant utilization rates were very low, resulting in a large amount of reactants remaining after the reaction, which is not conducive to post-processing and cost reduction. No side reactions were observed in Examples 1-12.

[0089] Performance test analysis of vulcanized rubber

[0090] Vulcanization performance test standard: GB / T1233-1992;

[0091] Tensile performance test standard: GB / T528-1998.

[0092] Table 2 shows the performance parameters of Examples 1 to 3, 5, 8 to 9 and Comparative Examples 1 to 3.

[0093] Table 2. Performance parameters of Examples 1-3, 5, 8-9 and Comparative Examples 1-3

[0094]

[0095] As can be seen from the results in Table 2, compared with Comparative Example 1, which was not treated with sodium carbonate, Example 1 shows that the vulcanization performance and tensile properties of the rubber are improved after sodium carbonate treatment. The comparison of the vulcanized rubber properties of Example 1 and Example 5 shows that too high an epoxy degree is detrimental to performance. The comparison of the vulcanized rubber properties of Examples 1 to 3 shows the effect of epoxy degree on rubber properties, indicating that the rubber obtained with an epoxy degree within the range of 3 to 20% has better performance. The comparison of Example 5 and Comparative Example 2 shows that, at the same epoxy degree, the epoxidized solution-polymerized styrene-butadiene rubber prepared by the method of the present invention has better rubber performance. Compared with Comparative Example 3, the vulcanized rubber prepared by the epoxidized solution-polymerized styrene-butadiene rubber obtained by the sodium carbonate solution treatment in the present application has better vulcanization performance and mechanical properties.

Claims

1. A method for preparing epoxidized solution-polymerized styrene-butadiene rubber, comprising the following steps: The method comprises adding solution-polymerized styrene-butadiene rubber to a solvent to prepare a glue solution, adding formic acid and a surfactant, stirring evenly, adding a hydrogen peroxide solution dropwise, and heating for reaction to obtain an epoxidized solution-polymerized styrene-butadiene rubber solution; adding a carbonate solution to the glue solution after the reaction to treat the solution to a pH of 7-10 to obtain a precipitated glue, and drying the solution to obtain the epoxidized solution-polymerized styrene-butadiene rubber; and the molar ratio of the hydrogen peroxide to the formic acid is 0.4-1.5:

1.

2. The preparation method according to claim 1, characterized in that The molar ratio of the hydrogen peroxide to the double bonds in the solution polymerized styrene-butadiene rubber is 0.01-0.5:

1.

3. The preparation method according to claim 2, characterized in that The molar ratio of the hydrogen peroxide to the double bonds in the solution-polymerized styrene-butadiene rubber is 0.04-0.4:

1.

4. The preparation method according to claim 1, characterized in that The solvent is selected from at least one of cyclohexane and n-hexane; and / or, The concentration of the glue solution is 5-20 g / 100 mL.

5. The preparation method according to claim 4, characterized in that The solvent is selected from cyclohexane, or a mixed solvent of cyclohexane and n-hexane; and / or, The concentration of the glue solution is 8-15 g / 100 mL.

6. The preparation method according to claim 1, characterized in that The surfactant is selected from at least one of anionic surfactants, nonionic surfactants, cationic surfactants, and amphoteric surfactants; and / or, Based on 100 g of the solution-polymerized styrene-butadiene rubber, the added amount of the surfactant is 1 to 10 drops.

7. The preparation method according to claim 6, characterized in that The surfactant is selected from at least one of sodium dodecylbenzenesulfonate, polysorbate, sorbitan fatty acid, polyethylene glycol, quaternary ammonium compound, and sodium dodecylaminopropionate; and / or, Based on 100 g of the solution-polymerized styrene-butadiene rubber, the amount of the surfactant added is 3 to 8 drops.

8. The preparation method according to claim 1, characterized in that The hydrogen peroxide solution is added at a rate of 1 to 10 mL / min; and / or The heating reaction temperature is 25-55°C; and / or, The heating reaction time is 1 to 4 hours.

9. The preparation method according to claim 8, characterized in that The hydrogen peroxide solution is added at a rate of 4 to 8 mL / min; and / or The heating reaction temperature is 35-45°C; and / or, The heating reaction time is 2 to 4 hours.

10. The preparation method according to claim 1, characterized in that The carbonate is selected from at least one of lithium carbonate, ammonium carbonate, sodium carbonate, potassium carbonate, and basic carbonate; and / or, The concentration of the carbonate solution is 2 to 15 g / 100 mL; and / or, The molar ratio of the carbonate to formic acid is 0.1 to 5:1; and / or, The temperature for adding the carbonate solution is 25-60°C.

11. The preparation method according to claim 10, characterized in that: The carbonate is selected from at least one of ammonium carbonate, sodium carbonate and potassium carbonate; and / or, The concentration of the carbonate solution is 4 to 10 g / 100 mL; and / or, The molar ratio of the carbonate to formic acid is 0.5 to 4:1; and / or, The temperature for adding the carbonate solution is 30-50°C.

12. An epoxidized solution-polymerized styrene-butadiene rubber prepared by the preparation method according to any one of claims 1 to 11.

13. The epoxidized solution-polymerized styrene-butadiene rubber according to claim 12, characterized in that The epoxy degree of the epoxidized solution-polymerized styrene-butadiene rubber is 3-30%.

14. The epoxidized solution-polymerized styrene-butadiene rubber according to claim 13, wherein The epoxy degree of the epoxidized solution-polymerized styrene-butadiene rubber is 5-20%.

15. The epoxidized solution-polymerized styrene-butadiene rubber obtained by the preparation method according to any one of claims 1 to 11 or the epoxidized solution-polymerized styrene-butadiene rubber according to any one of claims 12 to 14, used in a rubber composition.

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