Preparation method of epoxidized rubber, epoxidized rubber, epoxidized rubber nanocomposite and application

Abstract

The invention discloses a preparation method of epoxidized rubber, the epoxidized rubber, an epoxidized rubber nanocomposite and application. The preparation method of the epoxidized rubber comprises the step of treating an epoxidized rubber solution or latex by using a catalyst for decomposing hydrogen peroxide, the catalyst for decomposing hydrogen peroxide is selected from at least one of a metal simple substance, a metal oxide, a metal salt and an enzyme. The method disclosed by the invention is simple in process, high in efficiency, green, environment-friendly and low in cost, and solves the problem of side reaction caused by hydrogen peroxide in the rubber epoxidation post-treatment process and the process problems that an epoxidized glue solution containing a large amount of hydrogen peroxide cannot be directly applied to liquid-phase mixing, impregnation, foaming, injection molding, product extrusion and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of rubber modification, and specifically relates to a preparation method of epoxidized rubber, epoxidized rubber, an epoxidized rubber nanocomposite, and applications thereof. Background Art

[0002] Epoxidized rubber usually uses hydrogen peroxide as an oxidant to oxidize double bonds in the molecular chain into epoxy groups. Since polar epoxy groups are introduced into the molecular chain, the intermolecular force is enhanced and the flexibility is reduced, endowing the rubber with many properties that it originally did not have, such as good airtightness, oil resistance, compatibility with other polar rubbers, and can be further modified secondarily, using the epoxy group as a reactive group to introduce other functional groups. The application of epoxidized rubber is becoming increasingly widespread and has properties that cannot be replaced by other rubbers. It can be used to manufacture green tires, as adhesives, compatibilizers, and toughening agents. When epoxidized rubber is applied to the tread rubber of green tires, it has outstanding wet skid resistance and low rolling resistance, which is very beneficial to balancing the magic triangle performance.

[0003] Chuayjuljit S et al. epoxidized natural rubber in situ using formic acid and hydrogen peroxide. The epoxidized product was flocculated with methanol, washed with sodium carbonate solution and water, and then dried at 60 °C (Chuayjuljit S, Yaowsang C, Na-Ranong N, et al. Oil resistance and physical properties of in situ epoxidized natural rubber from high ammonia concentrated latex[J]. Journal of Applied Polymer Science, 2006, 100(5): 3948-3955). Chinese Patent CN101942043A provides a method for preparing epoxidized rubber, and the post-treatment process is to adjust the epoxidized natural rubber latex after the reaction to a pH value of 8-9 with ammonia water, and then coagulate and dry. Chinese Patent CN107880156A provides a method for preparing epoxidized liquid rubber, and the epoxidized liquid rubber after the reaction is washed to neutral and then dried. Chinese Patent CN102858005A uses centrifugal separation to remove organic peracid in the post-treatment process of epoxidized natural rubber. The above methods are inefficient and do not completely remove hydrogen peroxide. There is still a large amount of hydrogen peroxide in the rubber solution (latex) or flocculated rubber block after the reaction, and the epoxidation reaction and side reactions have not terminated. The hydroxyl radicals generated by the decomposition of hydrogen peroxide during drying and storage will also undergo ring-opening side reactions through a free radical mechanism. Moreover, the epoxidized rubber solution (latex) after the epoxidation reaction contains a large amount of hydrogen peroxide and cannot be directly stored and applied to the production processes such as the preparation of liquid-phase rubber nanocomposites, impregnation, foaming, injection molding, and extrusion products, which seriously restricts the industrial application of epoxidized rubber.

[0004] Therefore, it is necessary to improve the quality of epoxidized rubber, stably store the epoxidized rubber solution (latex), avoid ring-opening side reactions during the drying and storage of epoxidized rubber, and expand the application range of epoxidized rubber. Summary of the Invention

[0005] To solve the problems existing in the prior art, the present invention provides a method for preparing epoxidized rubber, epoxidized rubber, epoxidized rubber nanocomposite, and their applications. The method of the present invention has simple process, high efficiency, environmental protection, and low cost, and solves the problems of side reactions caused by hydrogen peroxide in the post-treatment process of rubber epoxidation and the problem that the epoxidized rubber solution contains a large amount of hydrogen peroxide and cannot be directly applied to processes such as liquid-phase mixing, impregnation, foaming, injection molding, and extrusion products.

[0006] One of the objectives of the present invention is to provide a method for preparing epoxidized rubber, which includes the step of treating an epoxidized rubber solution or latex with a catalyst for decomposing hydrogen peroxide; the catalyst for decomposing hydrogen peroxide is selected from at least one of elemental metals, metal oxides, metal salts, and enzymes. The activity range of the enzyme is preferably 50,000 to 2,000,000 enzyme activity, more preferably 400,000 to 800,000 enzyme activity.

[0007] In a preferred embodiment of the present invention,

[0008] the catalyst for decomposing hydrogen peroxide is selected from at least one of transition metal elements, transition metal oxides, transition metal salts, and enzymes, preferably Ag, Pt, Cr, MnO 2 , CuO, FeCl 3 , catalase (CAT), etc., and more preferably catalase. In the present invention, the metal salt is preferably used in the form of a metal salt solution, and the present invention does not limit the concentration of the metal salt solution. Those skilled in the art can set the concentration of the metal salt solution according to the actual situation.

[0009] In a preferred embodiment of the present invention,

[0010] the method includes: adding rubber into a solvent to form a solution or latex, then adding a surfactant, an epoxidation catalyst, and hydrogen peroxide to the solution or latex for an epoxidation reaction to obtain an epoxidized rubber solution or latex, and then adding a catalyst for decomposing hydrogen peroxide for treatment and an optional step of separating the epoxidation catalyst.

[0011] In the method, the order of adding a surfactant, an epoxidation catalyst, and hydrogen peroxide to the solution or latex is preferably to add the surfactant first; and / or,

[0012] In the method, the step of adding a catalyst for decomposing hydrogen peroxide for treatment and an optional step of separating the epoxidation catalyst can be to first optionally separate the epoxidation catalyst and then add the catalyst for decomposing hydrogen peroxide, or to first add the catalyst for decomposing hydrogen peroxide and then optionally separate the epoxidation catalyst.

[0013] In a preferred embodiment of the present invention,

[0014] The rubber is selected from rubbers containing double bonds. Preferably, the content of double bonds in the rubber is 0.05 - 2 mol double bonds / 100 g of rubber, preferably 0.05 - 1.85 mol double bonds / 100 g of rubber. More preferably, the rubber is selected from at least one of solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, natural rubber, chloroprene rubber, polybutadiene rubber, ethylene-propylene-diene monomer rubber, isoprene rubber, butyl rubber, silicone rubber, nitrile rubber, and eucommia rubber; the double bond is a carbon-carbon double bond; the rubber is in the form of latex or solid, and the solid rubber can also be oil-extended rubber; and / or,

[0015] The solvent is selected from good solvents for the rubber, preferably from at least one of cyclohexane, benzene, toluene, xylene, dichloromethane, dichloroethane, n-hexane, and water, more preferably from at least one of cyclohexane, n-hexane, and water; and / or,

[0016] The surfactant is a conventional surfactant in the art, preferably selected from at least one of anionic surfactants, cationic surfactants, zwitterionic surfactants, and nonionic surfactants, more preferably from at least one of AEO-9, AEO-15, TO-8, Tween 80, Tween 20, OP-10, and CTAB; and / or,

[0017] The epoxidation catalyst is selected from at least one of organic acids, heteropolyacid salts, lipases, metal oxides, and metal salts, preferably from at least one of formic acid, quaternary ammonium salt of phosphotungstic heteropolyacid, lipase, methyltrioxorhenium, molybdenum trioxide, porphyrin metal salt, manganese sulfate, and sodium bicarbonate; the lipase is preferably lipase 235. The epoxidation catalyst can be obtained commercially or prepared by any publicly known method in the prior art in this field.

[0018] In a preferred embodiment of the present invention,

[0019] The dosage ratio of the rubber to the solvent is 5 - 600 g of rubber / 100 mL of solvent, preferably 8 - 100 g of rubber / 100 mL of solvent, wherein the rubber is calculated based on the dry rubber content; and / or,

[0020] The dosage ratio of the surfactant to the rubber is 0 - 6 g of surfactant / 100 g of rubber, preferably 0.1 - 5 g of surfactant / 100 g of rubber, more preferably 0.2 - 3 g of surfactant / 100 g of rubber, wherein the rubber is calculated based on the dry rubber content; and / or,

[0021] The dosage ratio of the epoxidation catalyst to the rubber is 0.1 - 80 g of epoxidation catalyst / 100 g of rubber, preferably 0.5 - 50 g of epoxidation catalyst / 100 g of rubber, wherein the rubber is calculated based on the dry rubber content; and / or,

[0022] The dosage ratio of the hydrogen peroxide to the rubber is 5 - 480 g of hydrogen peroxide / 100 g of rubber, preferably 5 - 90 g of hydrogen peroxide / 100 g of rubber, wherein the rubber is calculated based on the dry rubber content; and / or,

[0023] The dosage ratio of the catalyst for decomposing hydrogen peroxide to the rubber is 0.1 - 5 g of the catalyst for decomposing hydrogen peroxide / 100 g of rubber, preferably 0.1 - 1 g of the catalyst for decomposing hydrogen peroxide / 100 g of rubber, wherein the rubber is calculated based on the dry rubber content.

[0024] In a preferred embodiment of the present invention,

[0025] The temperature of the epoxidation reaction is 20 - 70 °C, preferably 30 - 50 °C; and / or,

[0026] The time of the epoxidation reaction is 0.5 - 12 h, preferably 0.5 - 6 h; and / or,

[0027] The epoxidation reaction is carried out under stirring. Preferably, the stirring speed is 100 - 800 r / min, preferably 300 - 500 r / min; and / or,

[0028] The conditions of the treatment include: the temperature is 10 - 70 °C, preferably 10 - 50 °C; and / or, the time is 0.5 - 4 h, preferably 0.5 - 2 h; and / or, the stirring speed is 50 - 400 r / min, preferably 50 - 200 r / min; and / or,

[0029] The step of separating the epoxidation catalyst includes: when the epoxidation catalyst is an organic acid, adding a neutralizing agent for neutralization; and / or, when the epoxidation catalyst is a heteropolyacid salt, lipase, metal salt or metal oxide, the epoxidation catalyst can be removed by centrifugation or not removed; preferably,

[0030] After adding the catalyst for decomposing hydrogen peroxide for treatment and optionally separating the epoxidation catalyst, it further includes the steps of flocculation and drying; more preferably,

[0031] The flocculation is selected from at least one of chemical flocculation and physical flocculation, preferably selected from at least one of divalent metal salt / alcohol solution flocculation, alcohol flocculation, steam flocculation, and hot water flocculation; and / or,

[0032] The drying can adopt any drying method capable of removing the solvent, preferably selected from at least one of vacuum drying, atmospheric drying, microwave drying, and spray drying.

[0033] The second object of the present invention is to provide an epoxidized rubber obtained by the preparation method of one of the objects of the present invention. When in the preparation method of the epoxidized rubber, flocculation and drying are not carried out, the epoxidized rubber is an epoxidized rubber solution or latex, which can be directly applied to process fields such as liquid-phase mixing and impregnation; when in the preparation method of the epoxidized rubber, steps of flocculation and drying are included, the epoxidized rubber is a solid epoxidized rubber.

[0034] The third object of the present invention is to provide an application of the epoxidized rubber of the second object of the present invention in latex gloves, sounding balloons, adhesives, and impregnated products.

[0035] The fourth object of the present invention is to provide an epoxidized rubber composite material, especially an epoxidized rubber nanocomposite material, which is obtained by mixing and vulcanizing components including the epoxidized rubber of the second object of the present invention and rubber additives. The rubber additives are conventional additives in the art, such as antioxidants, etc., and those skilled in the art can add them according to actual situations, and their dosages are also conventional dosages. The process conditions of the mixing and vulcanization are also conventional process conditions in the art, and those skilled in the art can set them according to actual situations.

[0036] The fifth object of the present invention is to provide an application of the epoxidized rubber nanocomposite material of the fourth object of the present invention in rubber products, preferably in tires, sealing rings, rubber hoses, and tapes.

[0037] Compared with the prior art, the preparation method of the epoxidized rubber of the present invention has the following advantages:

[0038] 1. The preparation method of the epoxidized rubber of the present invention has the characteristics of being green and environmentally friendly, low in price, simple in process, high in process efficiency, and low in energy consumption;

[0039] 2. By adding a catalyst for decomposing hydrogen peroxide, the present invention enables the efficient decomposition of hydrogen peroxide, terminates the epoxidation reaction, reduces the free radical ring-opening side reaction during the drying and storage process, improves the performance and appearance of the product, and the catalyst for decomposing hydrogen peroxide does not need to be removed;

[0040] 3. The post-treatment method of the epoxidized rubber used in the present invention basically removes the residual hydrogen peroxide inside the epoxidized rubber, reducing the requirements for the drying equipment of the epoxidized rubber; the treated rubber solution (latex) after the epoxidation reaction can be stably stored and directly applied to production processes such as liquid-phase mixing, impregnation, foaming, injection molding, and extrusion products. Description of the Drawings

[0041] Figure 1 It is a comparison diagram of the nuclear magnetic resonance hydrogen spectra of Example 1 and Comparative Example 1. Among them, curve a represents the nuclear magnetic resonance hydrogen spectrum of Comparative Example 1, and curve b represents the nuclear magnetic resonance hydrogen spectrum of Example 1;

[0042] Figure 1 Among them, the peak at 5.1 ppm is the carbon-carbon double bond peak, the peak at 2.7 ppm is the epoxy group peak, and the peak at 3.6 - 3.7 ppm is the hydroxyl peak of the ring-opening reaction.

[0043] Figure 2 It is the comparison chart of the nuclear magnetic resonance hydrogen spectra of Example 2 and Comparative Example 2. Among them, curve c represents the nuclear magnetic resonance hydrogen spectrum of Comparative Example 2, and curve d represents the nuclear magnetic resonance hydrogen spectrum of Example 2;

[0044] Figure 2 Among them, the peak at 5.1 ppm is the carbon-carbon double bond peak, the peak at 2.7 ppm is the epoxy group peak, and the peak at 3.6 - 3.7 ppm is the hydroxyl peak of the ring-opening reaction. Detailed implementation mode

[0045] The present invention will be specifically described below in conjunction with specific embodiments and the accompanying drawings. It is necessary to point out here that the following embodiments are only used for further illustration of the present invention and cannot be understood as limiting the protection scope of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention still fall within the protection scope of the present invention.

[0046] The raw materials used in the examples are all conventional commercially available raw materials. The main raw materials are shown in Table 1:

[0047] Table 1 Specification table of main raw materials

[0048]

[0049] Testing method:

[0050] Nuclear magnetic resonance ( 1 H-NMR) analysis

[0051] It is tested with an AVANCE III analyzer produced by Bruker Corporation of the United States. The 1 H-NMR is used to quantitatively characterize the ring-opening rate of epoxidized rubber, and its value can be calculated according to the integral area of each characteristic peak in the double bond:

[0052]

[0053] Among them, K is the ring-opening rate of the sample, A epoxy , A C＝C , A -OH are the peak areas of the epoxy group, double bond, and hydroxyl group generated by ring-opening respectively.

[0054] The test conditions are as follows:

[0055] Solvent: deuterated chloroform (CDC 13); Spectral width: 0 ppm to 16 ppm; Central frequency: 8 ppm; Number of sampling times: 16.

[0056] Example 1

[0057] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, 2.5 g of TO-8 was added, and stirred for 20 min. Then, 20 g of formic acid (mass fraction 85%) and 92 g of H 2 O 2 (mass fraction 30%) were added, the rotation speed was set at 300 rpm, and the reaction was carried out at 45 °C for 2 hours. After the reaction was completed, 26.5 g of Na 2 CO 3 was added and stirred for neutralization and acid removal (stirred at 30 °C and 50 rpm for 20 min), 0.45 g of catalase (CAT) (400,000 enzyme activity, manufacturer: Macklin) was added dropwise at a speed of 1 ml / min and stirred to remove hydrogen peroxide (stirred at 30 °C and 50 rpm for 50 min), and then flocculated with absolute ethanol and vacuum dried to obtain epoxidized natural rubber.

[0058] Example 2

[0059] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 105 g of deionized water, 3.0 g of AEO-9 was added, and stirred for 20 min. Then, 25 g of formic acid (mass fraction 85%) and 92 g of H 2 O 2 (mass fraction 30%) were added, the rotation speed was set at 300 rpm, and the reaction was carried out at 35 °C for 5 hours. After the reaction was completed, 22 g of ammonia water was added and stirred for neutralization and acid removal (stirred at 15 °C and 50 rpm for 20 min), 0.6 g of MnO 2 was added and stirred to remove hydrogen peroxide (stirred at 15 °C and 50 rpm for 50 min), and then flocculated with hot water and dried at atmospheric pressure to obtain epoxidized natural rubber.

[0060] Example 3

[0061] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, 2.5 g of TO-8 was added, and stirred for 20 min. Then, 20 g of formic acid (mass fraction 85%) and 92 g of H 2 O 2 (mass fraction 30%) were added, the rotation speed was set at 300 rpm, and the reaction was carried out at 45 °C for 2 hours. After the reaction was completed, 26.5 g of Na 2 CO 3Stir and neutralize to remove acid (stir for 20 min at 30 °C and 50 rpm), and add dropwise an aqueous solution of FeCl containing 25% by mass of FeCl with a mass of 0.45 g at a rate of 1 ml / min 3 to remove hydrogen peroxide by stirring (stir for 50 min at 30 °C and 50 rpm), flocculate with absolute ethanol, and vacuum dry to obtain epoxidized natural rubber. 3 Example 4

[0062] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, add 2.5 g of TO-8, and stir for 20 min. Then, add 20 g of formic acid (mass fraction 85%), 92 g of H

[0063] O 2 O 2 (mass fraction 30%), set the rotation speed at 300 rpm, and react at 45 °C for 2 h. After the reaction is completed, add 26.5 g of Na 2 CO 3 Stir and neutralize to remove acid (stir for 20 min at 30 °C and 50 rpm), add 0.45 g of Ag to remove hydrogen peroxide by stirring (stir for 50 min at 30 °C and 50 rpm), flocculate with absolute ethanol, and vacuum dry to obtain epoxidized natural rubber.

[0064] Example 5

[0065] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, add 2.5 g of TO-8, and stir for 20 min. Then, add 20 g of formic acid (mass fraction 85%), 92 g of H 2 O 2 (mass fraction 30%), set the rotation speed at 300 rpm, and react at 45 °C for 2 h. After the reaction is completed, add 26.5 g of Na 2 CO 3 Stir and neutralize to remove acid (stir for 20 min at 30 °C and 50 rpm), add 0.45 g of MnO 2 to remove hydrogen peroxide by stirring (stir for 50 min at 30 °C and 50 rpm), flocculate with absolute ethanol, and vacuum dry to obtain epoxidized natural rubber.

[0066] Example 6

[0067] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, add 2.5 g of TO-8, and stir for 20 min. Then, add 20 g of formic acid (mass fraction 85%), 92 g of H2 O 2 (30% by mass), set the rotation speed to 300 rpm, and react at 45 °C for 2 hours. After the reaction is completed, add 26.5 g of Na 2 CO 3 Stir for neutralization and acid removal (stir at 30 °C and 50 rpm for 20 min), add 2.7 g of catalase (CAT) (400,000 enzyme activity, manufacturer: Macklin) dropwise at a rate of 1 ml / min, and stir to remove hydrogen peroxide (stir at 30 °C and 50 rpm for 50 min), flocculate with anhydrous ethanol, and vacuum dry to obtain epoxidized natural rubber.

[0068] Example 7

[0069] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, add 2.5 g of TO-8, and stir for 20 min. Then, add 20 g of formic acid (85% by mass), 92 g of H 2 O 2 (30% by mass), set the rotation speed to 300 rpm, and react at 45 °C for 2 hours. After the reaction is completed, add 26.5 g of Na 2 CO 3 Stir for neutralization and acid removal (stir at 30 °C and 50 rpm for 20 min), add 0.05 g of catalase (CAT) (400,000 enzyme activity, manufacturer: Macklin) dropwise at a rate of 1 ml / min, and stir to remove hydrogen peroxide (stir at 30 °C and 50 rpm for 50 min), flocculate with anhydrous ethanol, and vacuum dry to obtain epoxidized natural rubber.

[0070] Example 8

[0071] 100 g of nitrile rubber latex (NBRL Nipoi 5162, drc = 55%, the number of moles of double bonds per 100 g of dry rubber is 0.93 mol), diluted with 10 g of deionized water, add 2.7 g of AEO-15, and stir for 20 min. Then, add 13 g of formic acid (85% by mass), 80 g of H 2 O 2 (30% by mass), set the rotation speed to 500 rpm, and react at 45 °C for 5 hours. After the reaction is completed, add 10 g of ammonia water to stir for neutralization and acid removal (stir at 30 °C and 50 rpm for 20 min), add 1.0 g of Pt to stir to remove hydrogen peroxide (stir at 10 °C and 50 rpm for 70 min), flocculate with steam, and microwave dry to obtain epoxidized nitrile rubber.

[0072] Example 9

[0073] Add 100 g of cis-1,4-polybutadiene rubber (BR9000, the number of moles of double bonds in 100 g of rubber is 1.85 mol) and 1250 mL of dichloroethane into a container. After the BR is completely dissolved, add 0.5 g of Tween 20 and 6.8 g of MnSO 4 / NaHCO 3 (by mass ratio 1:1), and stir for 15 min. Add 35 g of H 2 O 2 (mass fraction 30%) into the rubber solution. Set the rotation speed at 500 rpm and react at 50 °C for 4.5 h. After the reaction is completed, centrifuge to remove the catalyst (MnSO 4 / NaHCO 3 ), add 0.4 g of CuO and stir to remove hydrogen peroxide (stir at 15 °C and 50 rpm for 75 min), flocculate with anhydrous methanol, and vacuum dry to obtain epoxidized cis-1,4-polybutadiene rubber.

[0074] Example 10

[0075] Add 137.5 g of solution-polymerized styrene-butadiene rubber (SSBR2557S, an oil-extended rubber, with 37.5 g of oil filled in every 100 g of rubber, the number of moles of double bonds in 100 g of rubber is 1.39 mol) and 2000 mL of n-hexane into a container. After the SSBR is completely dissolved, add 0.1 g of CTAB and stir for 15 min. Add 0.8 g of lipase 235 and 22 g of H 2 O 2 (mass fraction 30%) into the rubber solution. Set the rotation speed at 350 rpm and react at 50 °C for 6 h. After the reaction is completed, add 0.10 g of catalase (CAT) (800,000 enzyme activity, manufacturer: Macklin) dropwise at a speed of 1 ml / min and stir to remove hydrogen peroxide (stir at 25 °C and 50 rpm for 30 min), flocculate with absolute ethanol, and spray dry to obtain epoxidized solution-polymerized styrene-butadiene rubber.

[0076] Example 11

[0077] Add 100 g of Eucommia ulmoides gum (EUG, the number of moles of double bonds in every 100 g of dry gum is 1.45 mol) and 625 mL of cyclohexane into a container. After the EUG is completely dissolved, add 0.7 g of Tween 80 and 10.2 g of methyltrioxorhenium, and stir for 15 min. Add 35 g of H 2 O 2 (mass fraction 30%) into the rubber solution. Set the rotation speed at 480 rpm and react at 50 °C for 4 h. After the reaction is completed, centrifuge to remove the catalyst methyltrioxorhenium, add 0.4 g of MnO 2 and stir to remove hydrogen peroxide (stir at 28 °C and 50 rpm for 35 min), flocculate with absolute ethanol, and dry at atmospheric pressure to obtain epoxidized Eucommia ulmoides gum.

[0078] Example 12

[0079] Preparation of epoxidation catalyst CPC-PW 4 O 16 : Dissolve tungstic acid in 30% hydrogen peroxide, heat and stir until colorless, filter, and after cooling the filtrate to room temperature, add H 3 PO 4 . Stir for 0.5 h, then add a dichloromethane solution containing cetylpyridinium chloride dropwise to this solution, stir for another 0.5 h, separate the organic layer, and dry it with anhydrous Na 2 SO 4 . Evaporate the solvent to dryness to obtain [π-C 5 H 5 NC 16 H 33 3 [PW 4 O 16 , that is, CPC-PW 4 O 16 .

[0080] Add 100 g of butyl rubber (IIR1751, the number of moles of double bonds per 100 g of dry rubber is 0.16 mol) and 1000 mL of toluene to a container. After completely dissolving the IIR, add 0.7 g of Tween 20 and stir for 15 min; add 45 g of H 2 O 2 (30% by mass) and a mixed solution of 0.5 g of CPC-PW 4 O 16 . Set the rotation speed at 350 rpm and react at 25 °C for 3 h; after the reaction is completed, centrifuge to remove the catalyst (CPC-PW4O16), add a 25% FeCl 3 solution containing 0.8 g of FeCl 3 and stir to remove hydrogen peroxide (stir at 30 °C and a rotation speed of 50 rpm for 45 min), flocculate with anhydrous methanol, and vacuum dry to obtain epoxidized butyl rubber.

[0081] Comparative Example 1

[0082] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 85 g of deionized water, add 2.5 g of TO-8, and stir for 20 min. Then, add 20 g of formic acid (85% by mass), 92 g of H 2 O 2 (30% by mass), set the rotation speed at 300 rpm, and react at 45 °C for 2 h. After the reaction is completed, add 26.5 g of Na 2 CO 3 ​Stir and neutralize to remove acid (stir for 20 min at 30 °C and 50 rpm), then flocculate with absolute ethanol and vacuum dry to obtain epoxidized natural rubber.

[0083] Comparative Example 2

[0084] 100 g of concentrated natural rubber latex (drc = 60%, the number of moles of double bonds per 100 g of dry rubber is 1.45 mol), diluted with 105 g of deionized water, add 3.0 g of AEO-9 and stir for 20 min. Then, add 25 g of formic acid (mass fraction 85%), 92 g of H 2 O 2 (mass fraction 30%), set the rotation speed at 300 rpm and react at 35 °C for 5 h. After the reaction is completed, add 22 g of ammonia water to stir and neutralize to remove acid (stir for 20 min at 15 °C and 50 rpm), flocculate with hot water, and dry at atmospheric pressure to obtain epoxidized natural rubber.

[0085] The ring-opening rates of the epoxidized rubber measured after 48 h of storage calculated according to the nuclear magnetic resonance hydrogen spectrum of Examples 1-12 and Comparative Examples 1-2 are shown in Table 2.

[0086] Table 2 Ring-opening rates calculated from the nuclear magnetic resonance hydrogen spectrum tests of Examples 1-12 and Comparative Examples 1-2

[0087] Open-loop rate (%) Example 1 2.9 Example 2 3.2 Example 3 3.5 Example 4 3.2 Example 5 3.3 Example 6 3.0 Example 7 3.2 Example 8 3.6 Example 9 3.8 Example 10 3.0 Example 11 3.4 Example 12 3.6 Comparative Example 1 4.2 Comparative Example 2 5.7

[0088] It can be seen from Examples 1-12 and Comparative Examples 1-2 that: compared with Comparative Examples 1-2, under the same reaction conditions, in Examples 1-2, the hydrogen peroxide was removed in time using the preferred post-treatment method of the present invention, reducing the possible ring-opening side reaction during storage and drying, and the obtained epoxidized rubber had a lower ring-opening rate. In addition, it can be seen from Examples 1, 3-7 that in the present invention, when the catalyst for decomposing hydrogen peroxide is catalase, it has a more excellent effect of removing hydrogen peroxide, and when the dosage ratio of the catalyst for decomposing hydrogen peroxide to rubber is 0.1-5 g of catalyst for decomposing hydrogen peroxide / 100 g of rubber, preferably 0.1-1 g of catalyst for decomposing hydrogen peroxide / 100 g of rubber, it also has a more excellent effect of removing hydrogen peroxide.

Claims

1. A method for preparing epoxidized rubber, comprising the step of treating an epoxidized rubber solution or latex with a catalyst for decomposing hydrogen peroxide; the catalyst for decomposing hydrogen peroxide is selected from at least one of elemental metals, metal oxides, metal salts, and enzymes.

2. The preparation method according to claim 1, wherein: The catalyst for decomposing hydrogen peroxide is selected from at least one of transition metal elements, transition metal oxides, transition metal salts, and enzymes, preferably Ag, Pt, Cr, MnO 2 , CuO, FeCl 3 , and at least one of catalase, more preferably catalase.

3. The preparation method according to any one of claims 1-2, wherein the method includes: adding rubber into a solvent to form a solution or latex, then adding a surfactant, an epoxidation catalyst, and hydrogen peroxide to the solution or latex for an epoxidation reaction to obtain an epoxidized rubber solution or latex, and then adding a catalyst for decomposing hydrogen peroxide for treatment and an optional step of separating the epoxidation catalyst.

4. The preparation method according to claim 3, wherein: the rubber is selected from rubbers containing double bonds. Preferably, the content of double bonds in the rubber is 0.05-2 mol double bonds / 100 g rubber. More preferably, the rubber is selected from at least one of solution-polymerized styrene-butadiene rubber, emulsion-polymerized styrene-butadiene rubber, natural rubber, chloroprene rubber, polybutadiene rubber, ethylene-propylene-diene monomer rubber, isoprene rubber, butyl rubber, silicone rubber, nitrile rubber, and eucommia rubber; and / or, the solvent is selected from good solvents for the rubber, preferably at least one of cyclohexane, benzene, toluene, xylene, dichloromethane, dichloroethane, n-hexane, and water, more preferably at least one of cyclohexane, n-hexane, and water; and / or, the surfactant is selected from at least one of anionic surfactants, cationic surfactants, zwitterionic surfactants, and nonionic surfactants; and / or, the epoxidation catalyst is selected from at least one of organic acids, heteropolyacid salts, lipases, metal oxides, and metal salts, preferably at least one of formic acid, quaternary ammonium salt of phosphotungstic heteropolyacid, lipase, methyltrioxorhenium, molybdenum trioxide, porphyrin metal salt, manganese sulfate, and sodium bicarbonate.

5. The preparation method according to claim 3, wherein: the dosage ratio of the rubber to the solvent is 5-600 g rubber / 100 mL solvent, preferably 8-100 g rubber / 100 mL solvent; and / or, the dosage ratio of the surfactant to the rubber is 0-6 g surfactant / 100 g rubber, preferably 0.1-5 g surfactant / 100 g rubber; and / or, the dosage ratio of the epoxidation catalyst to the rubber is 0.1-80 g epoxidation catalyst / 100 g rubber, preferably 0.5-50 g epoxidation catalyst / 100 g rubber; and / or, the dosage ratio of the hydrogen peroxide to the rubber is 5-480 g hydrogen peroxide / 100 g rubber, preferably 5-90 g hydrogen peroxide / 100 g rubber; and / or, the dosage ratio of the catalyst for decomposing hydrogen peroxide to the rubber is 0.1-5 g catalyst for decomposing hydrogen peroxide / 100 g rubber, preferably 0.1-1 g catalyst for decomposing hydrogen peroxide / 100 g rubber.

6. The preparation method according to claim 3, wherein: the temperature of the epoxidation reaction is 20-70 °C, preferably 30-50 °C; and / or, The time of the epoxidation reaction is 0.5 to 12 h, preferably 0.5 to 6 h; and / or, The epoxidation reaction is carried out under stirring. Preferably, the stirring speed is 100 to 800 r / min, more preferably 300 to 500 r / min; and / or, The conditions of the treatment include: the temperature is 10 to 70 °C, preferably 10 to 50 °C; and / or, the time is 0.5 to 4 h, preferably 0.5 to 2 h; and / or, the stirring speed is 50 to 400 r / min, preferably 50 to 200 r / min; and / or, The step of separating the epoxidation catalyst includes: when the epoxidation catalyst is an organic acid, a neutralizing agent is added for neutralization; and / or, when the epoxidation catalyst is a heteropolyacid salt, lipase, metal salt or metal oxide, the epoxidation catalyst is removed by centrifugation; preferably, After adding a catalyst for decomposing hydrogen peroxide for treatment and optionally separating the epoxidation catalyst, the steps of flocculation and drying are further included; more preferably, The flocculation is selected from at least one of chemical flocculation and physical flocculation, preferably selected from at least one of divalent metal salt / alcohol solution flocculation, alcohol flocculation, steam flocculation, and hot water flocculation; and / or, The drying is selected from at least one of vacuum drying, atmospheric drying, microwave drying, and spray drying.

7. An epoxidized rubber obtained by the preparation method according to any one of claims 1-6.

8. An application of the epoxidized rubber according to claim 7 in latex gloves, sounding balloons, adhesives, and impregnated products.

9. An epoxidized rubber nanocomposite obtained by mixing and vulcanizing components including the epoxidized rubber according to claim 7 and rubber additives.

10. An application of the epoxidized rubber nanocomposite according to claim 9 in rubber products, preferably in tires, sealing rings, rubber hoses, and tapes.

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