Method for preparing hydrogenated rubber solution by one-step method

Abstract

The invention provides a method for preparing a hydrogenated rubber solution by a one-step method, which comprises the step of carrying out polymerization reaction on a comonomer and an alpha-olefin monomer in the presence of a polymerization initiator and an auxiliary agent to obtain the hydrogenated rubber solution. Compared with two processes of NBR emulsion polymerization and NBR emulsion or solution hydrogenation which are included in a traditional HNBR preparation method, the method has the advantages of being simple in technological process, low in energy consumption and the like. The preparation method is simple, convenient to operate and easy to realize industrialization; in the synthesis process, only free radical polymerization reaction occurs, so that the hydrogenation efficiency and the hydrogenation degree are high; according to the preparation method, the conversion rate of the monomer is extremely high, and the pollution to the environment after the unreacted monomer is volatilized is prevented. Besides, a certain amount of diene monomer can be further added into the reaction system, so that the hydrogenation degree of the hydrogenated rubber is regulated and controlled, and the requirements of different products are met.

Description

Technical Field

[0001] The present invention belongs to the field of special rubber synthesis, and particularly relates to a method for preparing a hydrogenated rubber solution by a one-step method. Background Art

[0002] Polymer reactions and their performance improvement are one of the important contents in the field of polymer materials science and engineering. Among them, the catalytic hydrogenation of polymers containing unsaturated double bonds / benzene rings is an important part of polymer reactions and modifications: for example, the hydrogenation of polystyrene (PS), the hydrogenation of styrene-diene monomer copolymers such as styrene-butadiene copolymer (SBS) and styrene-isoprene (SIS), and the selective or full hydrogenation of dicyclopentadiene polymers.

[0003] Polymer hydrogenation is usually divided into two methods: solution hydrogenation and emulsion hydrogenation. The principle of hydrogenation is that, with the assistance of homogeneous or heterogeneous catalysts, the polymer undergoes a hydrogenation reaction at a certain temperature and pressure, so that the double bond / benzene ring part or completely saturates. This method often greatly improves the performance of the polymer. For example, the product poly(cyclohexylethylene) (PCHE) after the hydrogenation of the above-mentioned polystyrene not only has improved heat resistance and aging resistance, but also greatly reduces its optical coefficient, so it can be used in the field of optical media; the hydroxide ion conductivity of hydrogenated polynorbornene becomes very good and its water absorption greatly decreases, so it can be widely used as an ion exchange membrane material.

[0004] However, the difficulty of polymer catalytic hydrogenation is much greater than that of low molecular weight catalytic hydrogenation. For heterogeneous catalysts, since the macromolecular chains of polymers exist in the form of randomly coiled coils in heterogeneous solutions, the hydrodynamic diameter of polymers is much larger than the scale of low molecular weight compounds; for homogeneous catalysts, the green and efficient removal of catalysts after the reaction is a great challenge, and their reaction activity is still greatly affected by the viscosity effect, resulting in extremely difficult diffusion of polymers in the internal pores of solid catalysts, or even unable to enter the pores of the catalysts. In such a situation, it is urgent to explore a catalyst and reaction system suitable for polymer hydrogenation to reduce the above adverse effects and the difficulty of polymer hydrogenation.

[0005] Hydrogenated nitrile rubber, abbreviated as HNBR or HSN, is a product obtained by hydrogenating and saturating the carbon-carbon double bonds in the molecular chain of nitrile rubber, and is also called highly saturated nitrile rubber. Hydrogenated nitrile rubber (HNBR) has good oil resistance, and has good resistance to fuel oil, lubricating oil and aromatic solvents; moreover, due to its highly saturated structure, it also has good heat resistance and excellent chemical corrosion resistance, and has good resistance to freon, acids and alkalis; at the same time, hydrogenated nitrile rubber (HNBR) also has high strength, high tear resistance and excellent wear resistance, etc., and is one of the rubbers with extremely excellent comprehensive performance.

[0006] At present, there are mainly three methods for preparing hydrogenated nitrile rubber (HNBR): solution hydrogenation method of nitrile rubber (NBR), emulsion hydrogenation method of nitrile rubber (NBR) and ethylene-acrylonitrile copolymerization method. The solution hydrogenation method is the only method for industrial production of HNBR. When preparing HNBR by this method, in the NBR solution, noble metals such as palladium, ruthenium and rhodium are used as catalysts, and hydrogen is used for hydrogenation. The solvents used include chlorobenzene, cyclohexanone, xylene and chloroform, etc.; this method has problems such as high catalyst cost and difficult separation, incomplete hydrogenation reaction of NBR, high reaction temperature, high pressure, and the use of a large amount of organic reagents is easy to cause environmental pollution. When preparing HNBR by the NBR emulsion hydrogenation method, the catalyst is directly added to the NBR emulsion, and the HNBR emulsion and raw rubber are prepared through a hydrogen reduction reaction; however, the micelle structure of the existing NBR emulsion is complex, there are various forms of micelles, and the size uniformity of the micelles is poor, and the particle size distribution range is large, which affects the hydrogenation effect of NBR and results in a low hydrogenation degree of NBR. In the ethylene-acrylonitrile copolymerization method, due to the large difference in the reaction rates of each monomer (C 丙烯腈 =0.04, C 乙烯 =0.8), the copolymerization reaction conditions are very harsh, and the resulting product has a high degree of molecular chain branching and poor randomness, and the polymer performance is not very good. This method is still in the small-scale research stage. Summary of the Invention

[0007] In order to improve the above technical problems, the present invention provides a method and application for preparing a hydrogenated rubber solution by a one-step method, aiming to solve the disadvantages of unstable product performance, cumbersome process flow, high energy consumption and large pollution caused by the inability to accurately control the hydrogenation degree of the hydrogenated rubber solution in the prior art. The present invention directly copolymerizes α-olefins and copolymerizable monomers to synthesize hydrogenated rubber by a one-step method, which has the advantages of saving time, reducing costs and being environmentally friendly. In addition, the hydrogenation degree of the hydrogenated rubber prepared by the one-step method of the present invention can reach 100%, and the hydrogenation degree of the hydrogenated rubber can be changed by adding diene monomers according to actual needs.

[0008] To achieve the above-mentioned invention object, the present invention adopts the following technical solutions:

[0009] The present invention provides a method for preparing a hydrogenated rubber solution by a one-step process, and the method comprises the following steps:

[0010] A copolymer monomer and an α-olefin monomer are subjected to a polymerization reaction in the presence of a polymerization initiator and an auxiliary agent simultaneously to obtain a hydrogenated rubber solution.

[0011] According to an embodiment of the present invention, the method specifically comprises the following steps:

[0012] S1. A polymerization initiator, an α-olefin monomer, a copolymer monomer, an auxiliary agent and an organic solvent are mixed to obtain a mixed solution;

[0013] S2. The mixed solution is subjected to a polymerization reaction under high pressure to obtain a hydrogenated rubber.

[0014] According to an embodiment of the present invention, the method specifically comprises the following steps:

[0015] S1. By mass, 0.01-0.1 part of a polymerization initiator, 25-45 parts of a copolymer monomer, 55-75 parts of an α-olefin monomer, 0.2-3.5 parts of an auxiliary agent and 100-700 parts of an organic solvent are mixed to obtain a mixed solution;

[0016] S2. The mixed solution is subjected to a polymerization reaction to obtain a hydrogenated rubber solution.

[0017] According to an embodiment of the present invention, in step S1, a certain amount of a diene monomer can be added, or the α-olefin monomer can be replaced with a diene monomer. Specifically, the addition amount of the diene monomer depends on the hydrogenation degree of the hydrogenated rubber. For example, the addition amount of the diene monomer by mass can be 0-10 parts, and exemplary amounts are 0 part, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 5.7 parts, 6 parts, 7 parts, 8 parts, 9 parts or 10 parts.

[0018] [Auxiliary agent]

[0019] According to an embodiment of the present invention, the auxiliary agent comprises a chain transfer agent and / or a pH regulator.

[0020] According to an embodiment of the present invention, the dosage of the chain transfer agent by mass is 0.2-1.0 part, preferably 0.5-1.0 part.

[0021] According to an embodiment of the present invention, the dosage of the pH regulator by mass is 0.02-0.10 part, preferably 0.02-0.06 part.

[0022] According to an embodiment of the present invention, the chain transfer agent is selected from at least one of n-dodecyl mercaptan, tert-dodecyl mercaptan, tert-butyl mercaptan, and n-butyl mercaptan.

[0023] In an embodiment of the present invention, the chain transfer agent is selected from dodecyl mercaptan. Dodecyl mercaptan has good performance and can effectively reduce the molecular weight of hydrogenated rubber.

[0024] According to an embodiment of the present invention, the pH regulator is selected from at least one of sodium phosphate, tetrasodium diphosphate, trisodium phosphate, sodium hexametaphosphate, and sodium bicarbonate.

[0025] According to an embodiment of the present invention, in step S1, the mixing can be carried out at room temperature.

[0026] According to an embodiment of the present invention, in step S2, the polymerization reaction can be carried out at a sub-high temperature or a high temperature. For example, the temperature of the sub-high temperature polymerization reaction is 50-70 °C, exemplarily 55 °C; the temperature of the high temperature polymerization reaction is 70-150 °C, exemplarily 105 °C.

[0027] According to an embodiment of the present invention, in step S2, the time of the polymerization reaction is 2-50 h, preferably 3-8 h, for example 5 h.

[0028] According to an embodiment of the present invention, in step S2, the air pressure of the high pressure is 5-15 MPa, for example 8 MPa.

[0029] According to an embodiment of the present invention, step S1 includes the following steps:

[0030] S1-a. First, dissolve the comonomer in an organic solvent to obtain a comonomer solution;

[0031] S1-b. Add the polymerization initiator, the chain transfer agent, and the pH regulator to the comonomer solution for mixing, and introduce an inert gas for degassing;

[0032] S1-c. Add the α-olefin monomer to the reaction system.

[0033] According to an embodiment of the present invention, in step S1-c, the α-olefin monomer is added to the degassed reaction system in a liquid state through a high-pressure inert gas. Preferably, the air pressure of the high-pressure inert gas is 2-8 MPa, for example 5 MPa. For example, the inert gas is selected from at least one of helium, argon, and nitrogen.

[0034] According to an embodiment of the present invention, in step S1-b, during the reaction, the acidity and alkalinity in the system cannot be automatically maintained constant but are in a dynamic change. Adding a pH regulator can effectively maintain the pH in the system within a small range, so that the surfactant can effectively maintain the liquid surface stability, which is beneficial to the reaction to proceed in stable micelles. In step S1-b, adding an appropriate amount of a chain transfer agent can effectively control the degree of polymerization and molecular weight, thereby ensuring the chemical and physical properties of the dry glue.

[0035] According to an embodiment of the present invention, the degassing in step S1-b is carried out under stirring conditions, and the inert gas is selected from at least one of helium, argon, and nitrogen.

[0036] According to an embodiment of the present invention, in step S1-c, a certain amount of diene monomer can be additionally added; alternatively, the α-olefin monomer can also be replaced with a diene monomer. Preferably, the addition amount of the diene monomer can be 0-10 parts, exemplarily 0 parts, 1 part, 2 parts, 3 parts, 4 parts, 5 parts, 5.7 parts, 6 parts, 7 parts, 8 parts, 9 parts, or 10 parts.

[0037] [Comonomer]

[0038] According to an embodiment of the present invention, the comonomer is selected from at least one of acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, propyl acrylate, butyl acrylate, propyl methacrylate, butyl methacrylate, fumaric acid, maleic acid, acrylic acid, and unsaturated carboxylic acids such as methacrylic acid.

[0039] [α-Olefin monomer]

[0040] According to an embodiment of the present invention, the α-olefin monomer is selected from α-olefin monomers of C 2 -C 6 , and the α-olefin monomers of C 2 -C 6 are selected from at least one of ethylene, 1-propene, 1-butene, 1-pentene, isopentene, and 1-hexene.

[0041] [Diene monomer]

[0042] According to an embodiment of the present invention, the diene monomer is a conjugated monomer, and the conjugated monomer is selected from at least one of conjugated dienes of C 4 -C 6 . Preferably, the diene monomer is selected from at least one of 1,3-butadiene, isoprene, 1-methylbutadiene, 2,3-dimethylbutadiene, piperylene, and chloroprene.

[0043] [Polymerization initiator]

[0044] According to an embodiment of the present invention, the polymerization initiator is at least one free radical initiator, including at least one of a peroxide initiator, an azo initiator, and a redox initiator.

[0045] According to an exemplary embodiment of the present invention, the peroxide initiator is an organic peroxide and / or an inorganic peroxide.

[0046] According to an exemplary embodiment of the present invention, the azo initiator includes at least one of azobisisobutyronitrile and azobisisoheptonitrile, etc.

[0047] According to an exemplary embodiment of the present invention, the redox initiator includes at least one of benzoyl peroxide / sucrose, tert-butyl hydroperoxide / rongalite, tert-butyl hydroperoxide / sodium metabisulfite, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite, hydrogen peroxide / tartaric acid, hydrogen peroxide / rongalite, ammonium persulfate / ferrous sulfate, hydrogen peroxide / ferrous sulfate, benzoyl peroxide / / N,N-diethylaniline, benzoyl peroxide / ferrous pyrophosphate, potassium persulfate / silver nitrate, persulfate / thiol, cumene hydroperoxide / ferrous chloride, potassium persulfate / ferrous chloride, hydrogen peroxide / ferrous chloride, cumene hydroperoxide / tetraethylenimine, and cumene hydroperoxide / ferrous sulfate, etc. Using a redox initiator can initiate a polymerization reaction at a lower temperature (0 - 50 °C), and can increase the reaction rate, reduce energy consumption, and the prepared latex has small particle size and a narrow particle size distribution range.

[0048] According to an embodiment of the present invention, the reaction kettle is selected from high-pressure reaction kettles, such as a high-temperature and high-pressure stainless steel reaction kettle.

[0049] According to an embodiment of the present invention, the high-temperature and high-pressure stainless steel reaction kettle includes a kettle body and at least two high-pressure resistant hoses. One end of the high-pressure resistant hose is connected to the kettle body, and the other end is connected to a high-pressure gas, and the high-pressure gas is, for example, an inert gas and hydrogen.

[0050] According to an embodiment of the present invention, the high-temperature resistant hose includes a stainless steel high-temperature resistant hose and a plastic high-temperature resistant hose. The stainless steel high-temperature resistant hose is used to introduce hydrogen into the kettle body, and the plastic high-temperature resistant hose is used to introduce an inert gas into the kettle body.

[0051] According to an embodiment of the present invention, an exhaust port is further provided on the kettle body.

[0052] According to an embodiment of the present invention, a pressure sensor is further provided in the kettle body, and the measuring range of the pressure sensor is -1 to 30 MPa.

[0053] According to an embodiment of the present invention, a temperature sensor is further provided in the autoclave body, and the measuring range of the temperature sensor is 0 to 180 °C.

[0054] According to an embodiment of the present invention, a stirring device is further provided in the autoclave body for fully mixing the materials in the system, and the stirring speed of the stirring device is 0 to 800 rpm.

[0055] According to an exemplary embodiment of the present invention, a method for preparing hydrogenated rubber by a one-step method includes the following steps:

[0056] 1) Dissolve the comonomer in an organic solvent to obtain a comonomer solution;

[0057] 2) Add a polymerization initiator, a chain transfer agent, and a pH regulator to the comonomer solution, mix them, and purge with an inert gas;

[0058] 3) Add the α-olefin monomer in a liquid form to the reaction solution through high-pressure nitrogen and mix;

[0059] 4) Apply pressure and raise the temperature to carry out a polymerization reaction, keep the temperature and pressure constant in the reaction autoclave, and obtain a hydrogenated rubber solution after stirring and polymerization.

[0060] According to an embodiment of the present invention, in step 3), a certain amount of diene monomer can be additionally added, or the α-olefin monomer can be replaced with a diene monomer. Adding an appropriate amount of diene monomer as a molecular weight regulator can effectively control the degree of polymerization and molecular weight of the hydrogenated rubber, thereby ensuring the chemical and physical properties of the solution or dry rubber.

[0061] According to an embodiment of the present invention, the definition and dosage of the diene monomer in step 3) are the same as above.

[0062] According to an embodiment of the present invention, the organic solvent can be selected from one of tetrahydrofuran and acetone, etc.

[0063] In the present invention, all solvents must be dehydrated before the polymerization reaction to avoid affecting the final experimental results. Under sub-high temperature conditions, tetrahydrofuran is preferably used as the solvent; under high temperature conditions, acetone is preferably used as the solvent.

[0064] In the present invention, an inert gas is introduced to displace the air in the reaction autoclave to ensure the purity of the gas in the autoclave, and the influence of air on the polymerization effect of the system can be eliminated.

[0065] The polymerization reaction temperature distribution for preparing hydrogenated rubber in the present invention is relatively wide, and the reaction is easier to control.

[0066] [Hydrogenated Rubber]

[0067] The present invention also provides a hydrogenated rubber solution prepared by the above method.

[0068] According to an embodiment of the present invention, the hydrogenated rubber solution is a hydrogenated nitrile rubber solution.

[0069] According to an embodiment of the present invention, the hydrogenated rubber molecules exist in an organic good solvent in the form of random coils.

[0070] According to an embodiment of the present invention, the solid content of the hydrogenated rubber solution is 5-50%, preferably 10-45%.

[0071] According to an embodiment of the present invention, the number-average molecular weight of the hydrogenated rubber is 6.0×10 4 ~8.0×10 4 , for example 6.0×10 4 , 6.2×10 4 , 6.6×10 4 , 7.0×10 4 , 7.3×10 4 , 7.4×10 4 , 7.7×10 4 , 7.9×10 4 or 8.0×10 4 .

[0072] According to an embodiment of the present invention, the weight-average molecular weight of the hydrogenated rubber is 19.0×10 4 ~24.0×10 4 , for example 19.0×10 4 , 19.5×10 4 , 20.2×10 4 , 22.3×10 4 , 22.6×10 4 , 23.2×10 4 or 24.0×10 4 .

[0073] Advantages of the present invention compared with the prior art:

[0074] The present invention uses a one-step method to prepare a hydrogenated rubber solution. The preparation method is simple, easy to operate, and easy to industrialize. And during the synthesis process, only free radical polymerization reactions occur, so the hydrogenation efficiency and hydrogenation degree are high. In the preparation method of the present invention, the conversion rate of monomers is extremely high, preventing environmental pollution caused by the volatilization of unreacted monomers.

[0075] In addition, the present invention can further add a certain amount of diene monomer to the reaction system to control the hydrogenation degree of the hydrogenated rubber to meet different product requirements. Detailed implementation manners

[0076] The technical solution of the present invention will be further described in detail below in conjunction with specific embodiments. It should be understood that the following embodiments are only for illustrative explanation of the present invention and should not be construed as limiting the protection scope of the present invention. All technologies implemented based on the above content of the present invention are covered within the scope of protection intended by the present invention.

[0077] Unless otherwise specified, the raw materials and reagents used in the following embodiments are all commercially available products or can be prepared by known methods.

[0078] Example 1

[0079] Preparation of hydrogenated rubber by sub-high temperature solution polymerization method, including the following steps:

[0080] 1) Dissolve 43 g of acrylonitrile in 400 g of tetrahydrofuran, mix evenly and add it to the reaction kettle;

[0081] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate and 0.06 g of initiator potassium persulfate to the reaction kettle, and degas by nitrogen bubbling for 30 min;

[0082] 3) Add 57 g of ethylene in liquid form to the reaction kettle under 5 MPa nitrogen high pressure, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0083] 4) Pressurize the nitrogen pressure in the reaction kettle to 8 MPa, raise the temperature of the reaction kettle to 55 °C, keep the temperature and pressure constant in the reaction kettle, stir at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 99% after 5 hours of polymerization reaction.

[0084] Example 2

[0085] Preparation of hydrogenated rubber by high temperature solution polymerization method, including the following steps:

[0086] 1) Dissolve 43 g of acrylonitrile in 400 g of acetone, mix evenly and add it to the reaction kettle;

[0087] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate and 0.06 g of initiator potassium persulfate to the reaction kettle, and degas by nitrogen bubbling for 30 min;

[0088] 3) Add 57 g of ethylene in liquid form to the reaction kettle under 5 MPa nitrogen high pressure, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0089] 4) Pressurize the nitrogen gas pressure in the reactor to 8 MPa, raise the temperature of the reactor to 105 °C, keep the temperature and pressure constant in the reactor, stir at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 99% after 5 hours of polymerization reaction.

[0090] Example 3

[0091] Prepare hydrogenated rubber by the secondary high-temperature solution polymerization method, including the following steps:

[0092] 1) Dissolve 43 g of acrylonitrile in 400 g of tetrahydrofuran, mix evenly and add it to the reactor;

[0093] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate, and 0.075 g of initiator azobisisobutyronitrile to the reactor, and degas by nitrogen bubbling for 30 min;

[0094] 3) Add 57 g of ethylene in liquid form to the reactor through 5 MPa nitrogen high pressure, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0095] 4) Pressurize the nitrogen gas pressure in the reactor to 8 MPa, raise the temperature of the reactor to 55 °C, keep the temperature and pressure constant in the reactor, stir at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 99% after 5 hours of polymerization reaction.

[0096] Example 4

[0097] Prepare hydrogenated rubber by the high-temperature solution polymerization method, including the following steps:

[0098] 1) Dissolve 43 g of acrylonitrile in 400 g of acetone, mix evenly and add it to the reactor;

[0099] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate, and 0.075 g of initiator azobisisobutyronitrile to the reactor, and degas by nitrogen bubbling for 30 min;

[0100] 3) Add 57 g of ethylene in liquid form to the reactor through 5 MPa nitrogen high pressure, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0101] 4) Pressurize the nitrogen gas pressure in the reactor to 8 MPa, raise the temperature to 105 °C, keep the temperature and pressure constant in the reactor, stir at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 99% after 5 hours of polymerization reaction.

[0102] Example 5

[0103] Prepare hydrogenated rubber by the secondary high-temperature solution polymerization method, including the following steps:

[0104] 1) Dissolve 43 g of acrylonitrile in 400 g of tetrahydrofuran, mix evenly and add it to the reaction kettle;

[0105] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate and 0.06 g of initiator potassium persulfate to the reaction kettle, and degas by nitrogen bubbling for 30 min;

[0106] 3) Add 57 g of ethylene and 5.3 g of butadiene in liquid form to the reaction kettle through 5 MPa high-pressure nitrogen, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0107] 4) Pressurize the nitrogen pressure in the reaction kettle to 8 MPa, raise the temperature of the reaction kettle to 55 °C, keep the temperature and pressure constant in the reaction kettle, keep the stirring at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 95% after 5 hours of polymerization reaction.

[0108] Example 6

[0109] Preparation of hydrogenated rubber by high-temperature solution polymerization method, including the following steps:

[0110] 1) Dissolve 43 g of acrylonitrile in 400 g of acetone, mix evenly and add it to the reaction kettle;

[0111] 2) Add 0.3 g of chain transfer agent tert-dodecyl mercaptan, 0.05 g of pH regulator sodium phosphate and 0.075 g of initiator azobisisobutyronitrile to the reaction kettle, and degas by nitrogen bubbling for 30 min;

[0112] 3) Add 57 g of ethylene and 5.3 g of butadiene in liquid form to the reaction kettle through 5 MPa high-pressure nitrogen, set the stirring paddle speed to 450 rpm and stir for 10 min for mixing;

[0113] 4) Pressurize the nitrogen pressure in the reaction kettle to 8 MPa, raise the temperature of the reaction kettle to 105 °C, keep the temperature and pressure constant in the reaction kettle, keep the stirring at a constant speed of 450 rpm, and obtain an HNBR solution with a hydrogenation degree of 95% after 5 hours of polymerization reaction.

[0114] After the reaction is completed, samples of the products of Examples 1-6 are taken, and the weight-average molecular weight and number-average molecular weight of the polymer are measured by gel permeation chromatography, and the solid content is measured to calculate the conversion rate. The results are shown in Table 1 below.

[0115] Monomer conversion rate = (system solid content * total system mass - mass of raw material non-volatile components) / total mass of raw material monomers.

[0116] The structure of the polymer was determined by FT-IR (BRUKER II, BRUKER instrument, Karlsruhe, Germany). FT-IR method: First, the latex sample was separated with ethanol to obtain the polymer solid. Then, a small amount of dry NBR solid was dissolved in MEK to form a homogeneous solution. Finally, the solution was dropped onto a potassium bromide sheet and dried to form a polymer film, and then infrared analysis was carried out.

[0117] The calculation of the hydrogenation degree was based on the corresponding absorbances of the characteristic peaks at 2236 cm -1 , 970 cm -1 and 723 cm -1 in the FT-IR spectrum.

[0118] 2236 cm -1 is the characteristic peak of the cyano group (-C≡N), 970 cm -1 is the characteristic peak of -C=C- (trans 1,4 structure), and 723 cm -1 is the characteristic peak of (-CH 2 ), n>4. n

[0119]

[0120]

[0121] K(723) = 0.255, K(970) = 2.3 are constants unique to HNBR

[0122] Then the relative amount of -C=C- in HNBR is:

[0123]

[0124] The relative amount of methylene formed by the hydrogenation of -C=C- in NBR is:

[0125]

[0126] Finally, the hydrogenation degree calculation formula is:

[0127]

[0128] Table 1 Experimental conditions of Examples 1-6 and test results of the prepared HNBR

[0129] Example Initiator g / phm Temperature °C Hydrogenation degree % Number-average molecular weight Weight-average molecular weight Conversion rate % Example 1 0.06 / 0.06 55 99 74,000 226,000 83 Example 2 0.06 / 0.06 105 99 62,000 195,000 71 Example 3 0.075 / 0.075 55 99 66,000 202,000 74 Example 4 0.075 / 0.075 105 99 79,000 240,000 86 Example 5 0.06 / 0.06 55 95 73,000 223,000 84 Example 6 0.075 / 0.075 105 95 77,000 232,000 86

[0130] As can be seen from the results in the above table, the hydrogenated rubber solution prepared by the one-step method of the present invention has stable performance, and the preparation method of the present invention is simple, convenient to operate, easy to industrialize, and the hydrogenation degree of the hydrogenated rubber is high. At the same time, by adding a certain amount of butadiene, the present invention can better control the hydrogenation degree of the hydrogenated rubber to meet the requirements of different products.

[0131] The embodiments of the present invention have been described above. However, the present invention is not limited to the above embodiments. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A one-step method for preparing a hydrogenated rubber solution, characterized in that: The method comprises the following steps: The comonomer and the α-olefin monomer are polymerized in the presence of a polymerization initiator and an auxiliary agent to obtain a hydrogenated rubber solution.

2. The method according to claim 1, characterized in that The method comprises the following steps: S1. The polymerization initiator, α-olefin monomer, comonomer, additive and organic solvent are mixed to obtain a mixed solution; S2. The mixed solution is polymerized under high pressure to obtain hydrogenated rubber.

3. The method according to claim 2, characterized in that The method comprises the following steps: S1. By mass, 0.01 to 0.1 parts of a polymerization initiator, 25 to 45 parts of a comonomer, 55 to 75 parts of an α-olefin monomer, 0.2 to 3.5 parts of an additive and 100 to 700 parts of an organic solvent are mixed to obtain a mixed solution; S2. subjecting the mixed solution to a polymerization reaction to obtain a hydrogenated rubber solution.

4. The method according to claim 3, characterized in that: In step S1, a certain amount of diene monomers may be added, or the α-olefin monomers may be replaced with diene monomers; preferably, the amount of diene monomers added is 0-10 parts by mass; And / or, the auxiliary agent includes a chain transfer agent and / or a pH adjuster; And / or, the amount of the chain transfer agent is 0.2 to 1.0 parts by mass, preferably 0.5 to 1.0 parts; And / or, the pH adjuster is used in an amount of 0.02-0.10 parts by mass, preferably 0.02-0.06 parts by mass.

5. The method according to claim 3, characterized in that: In step S2, the polymerization reaction is carried out at a sub-high temperature or high temperature; And / or, the temperature of the sub-high temperature polymerization reaction is 50-70°C; the temperature of the high temperature polymerization reaction is 70-150°C; And / or, in step S2, the polymerization reaction time is 2 to 50 hours, preferably 3 to 8 hours; And / or, in step S2, the high pressure gas pressure is 5-15 MPa, for example, 8 MPa.

6. The method according to any one of claims 2 to 5, characterized in that: Step S1 includes the following steps: S1-a, first dissolving the comonomer in an organic solvent to obtain a comonomer solution; S1-b, adding a polymerization initiator, a chain transfer agent and a pH adjuster to the comonomer solution, mixing, and introducing an inert gas for degassing; S1-c, adding α-olefin monomer into the reaction system; and / or, in step S1-c, the α-olefin monomer is added to the degassed reaction system in liquid form by means of high-pressure inert gas; And / or, the pressure of the high-pressure inert gas is 2-8 MPa.

7. The method according to any one of claims 1 to 6, characterized in that: The comonomer is selected from at least one of acrylonitrile, methacrylonitrile, styrene, α-methylstyrene, propyl acrylate, butyl acrylate, propyl methacrylate, butyl methacrylate, fumaric acid, maleic acid, acrylic acid and unsaturated carboxylic acid of methacrylic acid; And / or, the α-olefin monomer is selected from C2-C6 α-olefin monomers, and the C2-C6 α-olefin monomer is selected from at least one of ethylene, 1-propylene, 1-butene, 1-pentene, isopentene, and 1-hexene; And / or, the diene monomer is a conjugated monomer, and the conjugated monomer is selected from at least one of C4-C6 conjugated dienes; and / or, the diene monomer is selected from at least one of 1,3-butadiene, isoprene, 1-methylbutadiene, 2,3-dimethylbutadiene, piperylene and chloroprene; and / or, the polymerization initiator is at least one free radical initiator, including at least one of a peroxide initiator, an azo initiator and a redox initiator; and / or, the chain transfer agent is at least one selected from n-dodecyl mercaptan, tert-dodecyl mercaptan, tert-butyl mercaptan and n-butyl mercaptan; And / or, the pH adjuster is selected from at least one of sodium phosphate, tetrasodium diphosphate, trisodium phosphate, sodium hexametaphosphate and sodium bicarbonate. And / or, the azo initiator includes at least one of azobisisobutyronitrile and azobisisoheptanenitrile; And / or, the redox initiator includes at least one of benzoyl peroxide / sucrose, tert-butyl hydroperoxide / rongalite, tert-butyl hydroperoxide / sodium metabisulfite, benzoyl peroxide / N,N-dimethylaniline, ammonium persulfate / sodium bisulfite, potassium persulfate / sodium bisulfite, hydrogen peroxide / tartaric acid, hydrogen peroxide / rongalite, ammonium persulfate / ferrous sulfate, hydrogen peroxide / ferrous sulfate, benzoyl peroxide / / N,N-diethylaniline, benzoyl peroxide / ferrous pyrophosphate, potassium persulfate / silver nitrate, persulfate / thiol, cumene hydroperoxide / ferrous chloride, potassium persulfate / ferrous chloride, hydrogen peroxide / ferrous chloride, cumene hydroperoxide / tetraethyleneimine and cumene hydroperoxide / ferrous sulfate.

8. The method according to any one of claims 1 to 7, characterized in that: The following steps are involved: 1) dissolving the comonomer in an organic solvent to obtain a comonomer solution; 2) adding a polymerization initiator, a chain transfer agent, and a pH adjuster to the comonomer solution, mixing, and introducing an inert gas for degassing; 3) adding α-olefin monomer in liquid form into the reaction solution by high pressure nitrogen gas and mixing; 4) Pressurizing and heating to carry out polymerization reaction, maintaining constant temperature and pressure in the reactor, and obtaining a hydrogenated rubber solution after stirring and polymerization.

9. A hydrogenated rubber solution prepared by the method according to any one of claims 1 to 8.

10. The hydrogenated rubber solution according to claim 9, characterized in that The number average molecular weight of the hydrogenated rubber is 6.0×10 4 ~8.0×10 4 ; And / or, the weight average molecular weight of the hydrogenated rubber is 19.0×10 4 ~24×10 4 .

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