Flexible switching production process and equipment for rare earth isoprene, butadiene-isoprene and butadiene rubber

Abstract

The invention provides a flexible switching production process and equipment for rare earth isoprene, butadiene-isoprene and butadiene rubber, the flexible switching production equipment comprises a polymerization unit and a condensation unit, and the flexible switching production process comprises the following steps: mixing a monomer, a solvent and a rare earth catalyst to obtain a mixed solution; adding the mixed solution into a polymerization unit for polymerization reaction to obtain a rare earth isoamyl, butyl amyl or butadiene rubber solution; introducing the rare earth isoamyl, butyl amyl or butadiene rubber liquid into a coagulation unit for coagulation to obtain rare earth isoamyl, butyl amyl or butadiene rubber; wherein the monomer comprises at least one of butadiene and isoprene; the polymerization unit comprises a first kettle, a middle kettle and a tail kettle, and branching agent feeding holes are formed in the pipeline between the first kettle and the middle kettle, the 25% / 50% / 75% liquid level of the middle kettle and the pipeline between the middle kettle and the tail kettle. According to the process, shutdown for kettle cleaning is not needed, the isoprene rubber, the butadiene-isoprene rubber and the butadiene rubber can be flexibly switched and produced on the same polymerization device, and the overall production efficiency is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of polymer material preparation, and in particular to a flexible switching production process and equipment for rare earth isopentyl, butadiene-butadiene rubber and cis-butadiene rubber. Background Art

[0002] Since the molecular chain of rare earth cis-1,4-butadiene rubber has a high linearity, which leads to a high viscosity of the rubber liquid, making it difficult to transport and difficult to process in rubber mixing. Therefore, researchers considered introducing a branched structure into the molecular chain of rare earth cis-1,4-butadiene rubber to achieve the following goals: First, the branched structure can reduce the hydrodynamic volume of the molecular chain in the solution, thereby reducing the viscosity of the rubber liquid; second, the branched structure helps to improve the mixing processing performance, making it easier to disperse and mix the filler, thereby significantly reducing the Mooney viscosity of the mixed rubber; finally, the branched structure gives the rare earth rubber a higher resistance to cold flow, which is convenient for the storage and transportation of rubber blocks.

[0003] However, there are some problems with the existing branching methods. Although the commonly used external branching agents can achieve branching effects, such as silicon chloride, germanium chloride and tin chloride, they also bring some adverse effects, such as: branching agents are difficult to synthesize and lack industrial products, are expensive, and have obvious odor and high toxicity; in addition, the branching effect may not be ideal, and when the reaction activity is too high, it may cause Mooney jump and even cause significant gelation of the rubber. In non-polar polymerization solvents, such as n-hexane and cyclohexane, the solubility of the branching agent is poor and it is easy to precipitate from the solution, which not only affects the precise addition of the branching agent, but also is not conducive to its uniform dispersion in the rubber solution, resulting in severe local gelation, increased gel content, and a widening of the molecular weight distribution of the rubber, thereby affecting the rubber performance. In addition, the rare earth catalyst itself is an active polymerization system without chain termination reaction, and the active alkyl aluminum component in the catalyst will consume the branching agent, so the amount of branching agent used is often high. In addition, the residual halogen groups of the branching agent will undergo addition reaction with the residual double bonds in the butadiene rubber, resulting in a Mooney jump when the rubber solution stays in the rubber solution tank.

[0004] At present, commercial synthetic rubber products produced using rare earth catalysts are still relatively single, mainly rare earth cis-1,4-butadiene rubber, and usually adopt three or four kettles in series, full kettle overflow, and continuous polymerization process. The flexible switching continuous preparation process in the prior art allows the simultaneous production of two systems of cis-1,4-butadiene rubber through a set of polymerization devices without stopping to clean the kettle, thereby saving manpower and material resources, and improving production capacity and device utilization efficiency. However, if the polymerization system is directly switched without stopping to clean the kettle, there are still some problems, such as a long production cycle and more transition materials. This is because the glue or gel of the previous polymerization system remaining in the kettle may poison the catalyst of the new polymerization system, resulting in Mooney disorder, broadening of molecular weight distribution, increase in gel content, and even reduction in initial conversion rate, or even failure to polymerize. Although these problems can be avoided by switching the polymerization system after stopping to clean the kettle, doing so will increase time, manpower and material costs, and may increase potential accident risks.

[0005] In summary, the current rare earth long-chain branching modification technology and the synthetic rubber production process using rare earth catalysts still have certain shortcomings and need to be improved and optimized urgently. Summary of the invention

[0006] The present invention aims to solve the above problems by developing a series of diversified, high-value-added rare earth rubber products and long-chain branched modified products thereof using rare earth catalysts, thereby maximizing the utilization efficiency of the device. In the same polymerization device, flexible switching production of butadiene rubber, isoprene rubber, butadiene-pentadiene rubber and long-chain branched modified rubber can be achieved without stopping the reactor for cleaning. This not only avoids production fluctuations, reduces the generation of transition materials, saves time, manpower and material costs, but also effectively eliminates potential accident hazards.

[0007] To achieve the above-mentioned purpose, the present invention provides a flexible switching production process of rare earth isopentyl, butadiene-butadiene-isoprene and butadiene rubber. The flexible switching production process is carried out in a flexible switching production device. The flexible switching production device includes a polymerization unit and a condensation unit. The flexible switching production process includes the following steps: mixing a monomer, a solvent and a rare earth catalyst to obtain a mixed solution; adding the mixed solution to the polymerization unit for polymerization reaction to obtain a rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber solution; then introducing the rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber solution into the condensation unit for condensation to obtain a rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber; wherein the monomer includes at least one of butadiene and isoprene; the polymerization unit includes a first kettle, a middle kettle and a last kettle, and a branching agent feeding port is provided on the pipeline between the first kettle and the middle kettle, the 25% / 50% / 75% liquid level of the middle kettle, and the pipeline between the middle kettle and the last kettle.

[0008] Furthermore, the branching agent includes silicon tetrachloride, germanium tetrachloride, tin tetrachloride and alkyl trichlorides thereof; and / or the amount of the branching agent added is 0.01wt%-0.15wt% of the monomer; and / or the branching agent is introduced into the polymerization unit to start the branching reaction when the polymerization reaction conversion rate reaches 60%-100% and the Mooney value of the glue solution reaches 15-50 (ML 100℃ 1+4); and / or the solvent includes at least one of n-hexane, n-pentane, cyclopentane, cyclohexane, n-heptane, benzene and toluene.

[0009] Furthermore, the feed temperature of the mixed liquid is -10℃-70℃; the bottom temperature of the first kettle is 0℃-70℃, and the top temperature of the first kettle is 70℃-100℃; the bottom temperature of the middle kettle is 80℃-100℃, and the top temperature of the middle kettle is 85℃-100℃; the bottom temperature of the last kettle is 90℃-100℃, and the top temperature of the last kettle is 90℃-95℃; the gas phase pressure of the polymerization unit is 0.1MPa-1.0MPa, and the residence time of the rubber solution in the polymerization unit is 40min-180min.

[0010] Furthermore, a feeding port for a terminator is provided on the discharge pipeline of the final kettle, the terminator includes at least one of isooctyl alcohol, tetrahydrofurfuryl alcohol and menthol, and the added amount of the terminator is 1wt%-5wt% of the monomer; and / or a feeding port for an antioxidant is provided on the discharge pipeline of the final kettle, the antioxidant includes at least one of a hindered phenol antioxidant and a hindered amine antioxidant, and the added amount of the antioxidant is 0.1wt%-1.0wt% of the glue solution; and / or a feeding port for a viscosity reducer is provided on the discharge pipeline of the final kettle, the viscosity reducer includes at least one of a fatty acid and paraffin oil, and the added amount of the viscosity reducer is 0.1wt%-1.0wt% of the glue solution.

[0011] Furthermore, the flexible switching production equipment also includes a refining unit; the solvent mixture obtained by flash evaporation of the rare earth isopentyl, butadiene-pentyl or butadiene rubber solution obtained by the polymerization reaction, and the solvent mixture obtained by the condensation unit are sent to the refining unit, and the butadiene, isoprene and solvent recovered by the refining unit are sent to the polymerization unit.

[0012] Further, in the refining unit, when preparing butadiene rubber, the solvent mixture is sent to a butadiene recovery tower to recover butadiene monomer, and the kettle liquid of the butadiene recovery tower is sent to a solvent washing tower to start the solvent refining process; and / or when preparing isoprene rubber, the solvent mixture is sent to an isoprene recovery tower to recover isoprene monomer, and the kettle liquid of the isoprene recovery tower is sent to a solvent washing tower to start the solvent refining process; and / or when preparing butadiene-pentadiene rubber, the solvent mixture is sent to a butadiene recovery tower to recover butadiene monomer, the kettle liquid of the butadiene recovery tower is sent to an isoprene recovery tower to recover isoprene monomer, and the kettle liquid of the isoprene recovery tower is sent to a solvent washing tower to start the solvent refining process.

[0013] Furthermore, the solvent mixture enters a drying tower after passing through a butadiene recovery tower, an isoprene recovery tower or a solvent washing tower, and then enters a polymerization unit; wherein the operating temperature of the drying tower is 10° C.-70° C., and the operating pressure of the drying tower is 0.1 MPa-1.0 MPa.

[0014] Furthermore, the flexible switching production equipment also includes a post-processing unit, which is arranged after the condensation unit. The post-processing unit includes extrusion dehydration treatment, expansion drying treatment, and fluidized bed drying treatment in sequence.

[0015] Furthermore, the polymerization unit includes a first static mixer and a second static mixer; the monomer and the solvent enter the first static mixer for premixing to obtain a premix, and the premix and the rare earth catalyst enter the second static mixer for mixing to obtain a mixed liquid.

[0016] The present invention also provides a flexible switching production device, which adopts the flexible switching production process as described above.

[0017] After adopting the technical solution of the present invention, the following technical effects can be achieved: (1) Branching agents have superior performance: Branching agents are industrial products with a wide range of sources, no odor, low price, and high activity, which can effectively improve the efficiency of branching reactions and product quality; (2) Efficient production of diversified rubber products: Using a rare earth catalytic system, this production process can efficiently produce a series of diversified rare earth rubber products and high value-added long-chain branched modified products, thereby maximizing the utilization efficiency of the equipment; (3) Flexible production switching to reduce costs and risks: This process does not require stopping for kettle cleaning and can flexibly switch the production of isoprene rubber, butylene rubber, cis-1,4-butadiene rubber and long-chain branched modified rare earth rubber on the same polymerization unit, thus avoiding production fluctuations, reducing the generation of transition materials, saving time, material and labor costs, and reducing potential accident hazards. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which: Figure 1 A schematic diagram of a process flow of a polymerization unit provided in an embodiment of the present invention; Figure 2 A schematic diagram of a process flow of a flexible switching production process provided by an embodiment of the present invention; Figure 3 A schematic flow chart of a drying process in a refining unit provided in an embodiment of the present invention; Figure 4A schematic structural diagram of a stirring device in a polymerization unit provided in an embodiment of the present invention.

[0019] Description of reference numerals: 10-polymerization unit; 11a-first kettle; 11b-middle kettle; 11c-last kettle; 12a-first monomer feed port; 12b-second monomer feed port; 12c-third monomer feed port; 12d-fourth monomer feed port; 13-solvent feed port; 14-rare earth catalyst feed port; 15a-first static mixer; 15b-second static mixer; 16a-first flushing solvent feed port; 16b-second flushing solvent feed port; 17-branching agent feed port; 18-deactivating agent Feed inlet; 19-discharge port of colloid solution; 20-condensation unit; 21-flash tank; 22-blending tank; 23-recovery tank; 30-refining unit; 31-butadiene recovery tower; 32-butadiene refining unit; 33-butadiene drying tower; 34-isoprene recovery tower; 35-isoprene refining unit; 36-isoprene drying tower; 37-solvent refining unit; 38-solvent drying tower; 39-drying tower; 40-post-processing unit; 51-ribbon agitator; 52-baffle. DETAILED DESCRIPTION

[0020] In order to make the above-mentioned purposes, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0021] The embodiment of the present invention provides a flexible switching production process of rare earth isopentyl, butadiene-butadiene-isoprene and butadiene rubber. The flexible switching production process is carried out in a flexible switching production device. The flexible switching production device includes a polymerization unit 10 and a condensation unit 20. The flexible switching production process includes the following steps: mixing a monomer, a solvent and a rare earth catalyst to obtain a mixed solution; adding the mixed solution to the polymerization unit 10 for polymerization reaction to obtain a rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber glue solution; then introducing the rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber glue solution into the condensation unit 20 for condensation to obtain a rare earth isopentyl, butadiene-butadiene-isoprene or butadiene rubber; wherein the monomer includes at least one of butadiene and isoprene; the polymerization unit 10 includes a first kettle 11a, a middle kettle 11b and a last kettle 11c, and a branching agent feeding port 17 is provided on the pipeline between the first kettle 11a and the middle kettle 11b, the 25% / 50% / 75% liquid level of the middle kettle 11b, and the pipeline between the middle kettle 11b and the last kettle 11c.

[0022] like Figure 1As shown, the flexible switching production process can switch the production of different types of rubbers according to demand in the same production equipment, such as rare earth isopentyl, butylene, butadiene rubber, and this flexibility makes the production process more efficient and adaptable, adapting to changes in market demand. The polymerization unit 10 includes multiple reactors, such as the first reactor 11a, the middle reactor 11b and the last reactor 11c, and a branching agent feed port 17 is provided between each reactor. By controlling the liquid level between different reactors, such as the 25%, 50%, and 75% liquid level of the middle reactor 11b, the polymerization process can be accurately controlled to ensure that the production requirements of different rubbers are accurately met. The process first mixes butadiene monomer or isoprene monomer, solvent and rare earth catalyst to obtain a mixed solution, and then enters the polymerization unit 10 for polymerization reaction, thereby producing different types of rubber glue. After the polymerization reaction, rare earth isopentyl, butylene or butadiene rubber glue will be introduced into the condensation unit 20 for condensation treatment, and finally solid rubber is obtained. The setting of the condensation unit 20 ensures the quality and stability of the rubber product.

[0023] Flexible switching means that in the same production process, the type of rubber produced can be flexibly adjusted as needed. This technology breaks through the traditional single production line model and can produce multiple types of rubber more efficiently, reducing equipment downtime and resource waste. The use of rare earth catalysts helps to improve the efficiency of the polymerization reaction and can control the selectivity of the reaction to ensure that different types of rubber have specific molecular structures and properties. By setting the liquid level and feeding port between the reactors, each step in the production process can be precisely controlled. For example, the setting of the branching agent feeding port 17 can affect the molecular structure of the rubber and thus adjust the properties of the rubber.

[0024] Specifically, the present invention selectively opens different monomer feed ports according to different target products, such as the first monomer feed port 12a, the second monomer feed port 12b, the third monomer feed port 12c, and the fourth monomer feed port 12d. For example, when producing cis-1,4-butadiene rubber, only the butadiene feed port and the solvent feed port 13 are opened, and the feed lines of other monomers are cut off; when producing butadiene-1,4-pentadiene rubber, the butadiene feed port, the isoprene feed port and the solvent feed port 13 are opened at the same time, and the feed lines of other monomers are cut off; when producing isoprene rubber, only the isoprene feed port and the solvent feed port 13 are opened. It should be noted that the grades with low Mooney and high branching degree are selected for production at 25% and 50% liquid levels; while the grades with high Mooney and low branching degree are selected for production at 75% and 100% liquid levels.

[0025] Furthermore, in order to produce long-chain branched modified rubber products with different branching structures, the present invention provides branching agent feeding ports on the glue pipeline between the first kettle 11a and the middle kettle 11b, at the 25%, 50% and 75% liquid levels of the middle kettle 11b, and on the glue pipeline between the middle kettle 11b and the last kettle 11c. According to the control requirements of different branching structures, the branching agent feeding port 17 at a specific position can be selectively opened to continuously add branching agent to the rare earth glue. At this time, the temperature of the glue is maintained at 70°C-100°C, the pressure is 0.1MPa-1.0MPa, and the glue concentration is 10%-20%. The concentration of the branching agent can be flexibly adjusted according to needs, ranging from 0.001g / L-1000g / L. The amount of branching agent added is based on a mass fraction of butadiene of 0.01%-0.15%. The branching agent diluent is added to the rare earth butadiene rubber solution when the conversion rate of the rare earth polymerization reaction reaches 60%-100% and the Mooney value reaches 15-50 (ML 100℃ 1+4), thereby starting the branching reaction. At the second flushing solvent feed port 16b, the branching agent diluent is fed into the reactor through the flushing oil and is fully mixed with the rare earth butadiene rubber solution.

[0026] In order to prevent the Mooney value of the glue liquid from rising sharply in the mixing tank 22, the present invention also adds an inactivator, i.e., water, to the discharge pipeline of the final kettle 11c. Water can be directly added to the rare earth glue liquid, or mixed with alcohol substances such as ethanol and added, and the added amount is designed to be 1.2-2.0 according to the molar ratio of water to chlorine. Furthermore, the discharge pipeline of the final kettle 11c is provided with an inactivator feed port 18 and a glue liquid discharge port 19.

[0027] In some embodiments of the present application, the branching agent includes silicon tetrachloride, germanium tetrachloride, tin tetrachloride and alkyl trichlorides thereof; and / or the amount of the branching agent added is 0.01wt%-0.15wt% of the monomer; and / or the branching agent is fed into the polymerization unit 10 to start the branching reaction when the polymerization reaction conversion rate reaches 60%-100% and the Mooney value of the glue reaches 15-50 (ML 100℃ 1+4); and / or the solvent includes at least one of n-hexane, n-pentane, cyclopentane, cyclohexane, n-heptane, benzene and toluene.

[0028] Branching agents include silicon tetrachloride, germanium tetrachloride, tin tetrachloride and their alkyl trichlorides. Branching agents are chemical substances used to promote branching reactions of polymer chains. By introducing specific branching agents, the degree of branching of polymers can be precisely controlled, thereby improving the mechanical properties, processing properties and high temperature resistance of polymers. In addition, the use of these branching agents can improve the efficiency of polymerization reactions and optimize the molecular structure of polymers, making them have better performance and wider applicability in applications.

[0029] Preferably, the branching agent can be silicon tetrachloride, methyl silicon trichloride, ethyl silicon trichloride, n-propyl silicon trichloride, isopropyl silicon trichloride, n-butyl silicon trichloride, isobutyl silicon trichloride, tert-butyl silicon trichloride, sec-butyl silicon trichloride, octyl silicon trichloride, germanium tetrachloride, methyl germanium trichloride, ethyl germanium trichloride, n-propyl germanium trichloride, isopropyl germanium trichloride, n-butyl germanium trichloride, isobutyl germanium trichloride, tert-butyl germanium trichloride, sec-butyl germanium trichloride, octyl germanium trichloride, tin tetrachloride, methyl tin trichloride, ethyl tin trichloride, n-propyl tin trichloride, isopropyl tin trichloride, n-butyl tin trichloride, isobutyl tin trichloride, tert-butyl tin trichloride, sec-butyl tin trichloride, octyl tin trichloride. At the first flushing solvent feed port 16a, the branching agent is flushed into the reactor from the front and rear glue lines and different liquid levels of the polymerization reactor by flushing oil, and is fully mixed with the rare earth butadiene rubber solution.

[0030] In order to ensure the accurate addition and effective dispersion of the branching agent, the present invention also adopts alcohols such as ethanol, isopropanol, n-butanol, n-octanol, isooctyl alcohol as the diluent of the branching agent. Alcohols can dissolve the branching agent well, thereby ensuring the uniform distribution of the branching agent and improving the controllability of the branching reaction. In this way, the Mooney viscosity can be accurately adjusted, a narrower molecular weight distribution is maintained, and the gel content is reduced simultaneously. The effect of the alcohol solubilization branching agent is also to improve the efficiency of the branching reaction and reduce the addition amount of the branching agent. The concentration of the branching agent solution can be flexibly adjusted as needed, ranging from 0.001g / L to 1000g / L. Alcohols can also deactivate rare earth catalysts, thereby further reducing the amount of branching agents used. The molar ratio of alcohols to neodymium is in the range of 40-3000 / 1.

[0031] The amount of branching agent added is 0.01wt%-0.15wt% of the monomer. Accurately controlling the amount of branching agent added can make the polymer reach the required branching degree, avoiding the impact of excessive or insufficient branching on the performance of the final polymer. The appropriate amount of addition can ensure that the fluidity, processing performance and physical and chemical properties of the polymer are optimized, and improve the consistency and stability of the product.

[0032] When the polymerization reaction conversion rate reaches 60%-100% and the Mooney value of the gel reaches 15-50 (ML 100℃ 1+4), the branching agent is introduced into the polymerization unit 10 to start the branching reaction. At this time, the length of the polymer chain is long enough, which is conducive to the effective development of the branching reaction without affecting the controllability of the reaction. In addition, controlling the timing of the branching reaction can improve the uniformity and performance stability of the polymer and avoid the adverse effects caused by the introduction of the branching agent too early or too late.

[0033] The solvent includes at least one of n-hexane, n-pentane, cyclopentane, cyclohexane, n-heptane, benzene and toluene. By selecting a suitable solvent, the solvation effect, reaction rate and solubility of the polymerization reaction can be effectively controlled. The selection of different solvents can optimize the molecular structure, particle size distribution and other properties of the polymer under different reaction conditions, and further improve the quality and performance of the polymer. The use of these solvents can also improve the solubility and dispersibility of the reaction, promote the uniformity of the reaction, and thus obtain a higher quality polymer product. The designed concentration of the monomer solution can be adjusted between 5% and 25% as needed.

[0034] After the branching reaction is completed, water is added to the rare earth glue to react with the halogen groups remaining in the branching agent to quickly quench the branching agent. This can ensure that the Mooney viscosity of the rare earth glue is stable during storage and will not jump. Water can be added directly to the glue or mixed with alcohols such as ethanol before adding. The molar ratio of water to chlorine is designed to be 1.0-10.0 / 1.

[0035] In some embodiments of the present application, the feed temperature of the mixed liquid is -10℃-70℃; the bottom temperature of the first kettle 11a is 0℃-70℃, and the top temperature of the first kettle 11a is 70℃-100℃; the bottom temperature of the middle kettle 11b is 80℃-100℃, and the top temperature of the middle kettle 11b is 85℃-100℃; the bottom temperature of the last kettle 11c is 90℃-100℃, and the top temperature of the last kettle 11c is 90℃-95℃; the gas phase pressure of the polymerization unit 10 is 0.1MPa-1.0MPa, and the residence time of the glue in the polymerization unit 10 is 40min-180min.

[0036] The present invention provides specific settings for the mixed liquid feed temperature, the temperature of each kettle body, and the pressure and residence time of the polymerization unit 10 to optimize the reaction process and improve the reaction efficiency. The control of the feed temperature range can effectively adjust the viscosity of the feed and its reactivity with other reactants, thereby ensuring the smooth progress of the reaction; in the first kettle 11a, the setting of the temperature gradient from the bottom to the top helps to gradually activate the reaction process, control the initial reaction rate, and avoid violent reactions or incomplete reactions; in the middle kettle 11b, the temperature continues to rise to a higher level to ensure the effective progress of the mid-term polymerization reaction and further improve the degree of polymerization of the product; the temperature of the last kettle 11c is controlled in the high temperature zone to promote the reaction to reach the final completion, ensure the complete polymerization or other chemical changes of the product, and ensure the quality of the final product; the gas phase pressure range of the polymerization unit 10 can adjust the reaction atmosphere and control the reaction rate, and the residence time ensures that the reaction process is sufficient and the expected polymerization effect is obtained.

[0037] By precisely controlling the temperature gradient of each reactor, the rate and efficiency of the polymerization reaction can be optimized. The rate of the reaction start is controlled at low temperature, and the temperature is gradually increased as the reaction proceeds to avoid reaching too high a reaction rate too early, thereby improving the uniformity of the molecular weight distribution and the degree of polymerization of the product.

[0038] Specifically, the polymerization production process of this embodiment is as follows: First, the polymerization reaction is started by continuously introducing a monomer / solvent mixture and a rare earth catalyst into the polymerization first kettle 11a of the reaction device. The polymerized glue then flows out from the top of the first kettle 11a, passes through the glue pipeline connecting the first kettle 11a and the middle kettle 11b, and enters the middle kettle 11b from the bottom of the middle kettle 11b to continue the chain growth reaction. The glue then flows out from the top of the middle kettle 11b, passes through the glue pipeline and enters the final kettle 11c from the bottom. At this time, the conversion rate of the rare earth glue in the middle kettle 11b has basically reached 100%, and the final kettle 11c can further improve the conversion rate. Finally, the rare earth glue flows out through the discharge pipeline at the top of the final kettle 11c to obtain the final rare earth glue product.

[0039] like Figure 4 As shown, further, due to the problems of glue hanging in the kettle and the agitator holding the shaft in the rare earth polymerization system, these problems may lead to an increase in the gel content of the product and the occurrence of stopping to clean the kettle during production. To solve these problems, the present invention adopts a frame-type, screw-belt-type, shaftless structure, and a design of a multi-layer baffle 52 built into the stirring device; the stirring device includes a screw-belt-type stirring paddle 51 and a baffle 52. This design not only improves the mixing effect of the materials, but also effectively avoids the occurrence of the rubber holding the shaft phenomenon.

[0040] In some embodiments of the present application, a feeding port for a terminator is provided on the discharge pipeline of the final kettle 11c, and the terminator includes at least one of isooctyl alcohol, tetrahydrofurfuryl alcohol and menthol, and the added amount of the terminator is 1wt%-5wt% of the monomer; and / or a feeding port for an antioxidant is provided on the discharge pipeline of the final kettle 11c, and the antioxidant includes at least one of a hindered phenol antioxidant and a hindered amine antioxidant, and the added amount of the antioxidant is 0.1wt%-1.0wt% of the glue; and / or a feeding port for a viscosity reducer is provided on the discharge pipeline of the final kettle 11c, and the viscosity reducer includes at least one of a fatty acid and paraffin oil, and the added amount of the viscosity reducer is 0.1wt%-1.0wt% of the glue.

[0041] During the discharge process of the final reactor 11c, specific additives such as terminators, antioxidants and viscosity reducers are used to regulate the performance of the discharged glue liquid, thereby optimizing the quality and performance of the final product. The addition of terminators is mainly used to terminate the polymerization reaction, control the end time of the polymerization reaction and the length of the product molecular chain; by selecting terminators such as isooctyl alcohol, tetrahydrofurfuryl alcohol or menthol, the reaction rate can be effectively controlled to prevent the occurrence of side reactions, thereby improving the stability of the product. The addition of antioxidants can effectively prevent the glue liquid from oxidizing during storage and use; oxidation reactions not only affect the physical properties of the glue liquid such as viscosity and transparency, but also may cause a decrease in product performance; hindered phenol antioxidants and hindered amine antioxidants can effectively inhibit oxidation reactions, thereby extending the storage stability and service life of the glue liquid. The addition of viscosity reducers can be used to improve the fluidity of the glue liquid, reduce its viscosity, and facilitate subsequent processing and transportation; viscosity reducers such as fatty acids and paraffin oil can adjust the viscosity of the glue liquid, making the glue liquid easier to handle, coat or inject, and will not affect the final performance of the glue liquid.

[0042] Specifically, after the polymerization reaction is completed, it is necessary to add a terminator to the discharge line of the polymerization end kettle 11c. Considering that the solvent recovered by the condensation unit 20 and butadiene and isoprene may contain alcohol terminators, in order to avoid the accumulation of terminators causing an increase in the load on the refining unit 30, thereby affecting the efficiency of the rare earth polymerization reaction, this embodiment preferably selects high-boiling-point, easily separable alcohol terminators such as isooctyl alcohol, tetrahydrofurfuryl alcohol or menthol. In addition, in order to prevent the rubber product from oxidative degradation when it encounters air in the later stage, it is also necessary to add an antioxidant to the discharge line. In order to improve the conveying capacity of the rare earth glue, a viscosity reducer is also required. Next, the rare earth glue will be introduced into the condensation unit 20 for condensation treatment. The oil locking rate of the colloid particles after condensation is less than 1%, and then it is sent to the post-processing unit 40 for extrusion dehydration, expansion drying and fluidized bed drying. Finally, after weighing, briquetting and packaging steps, a rare earth rubber product is finally obtained.

[0043] In some embodiments of the present application, the flexible switching production equipment also includes a refining unit 30; the solvent mixture obtained by flash evaporation of the rare earth isopentyl, butadiene-pentyl or butadiene rubber solution obtained by the polymerization reaction, and the solvent mixture obtained by the condensation unit 20 are sent to the refining unit 30, and the butadiene, isoprene and solvent recovered by the refining unit 30 are sent to the polymerization unit 10.

[0044] In the polymerization process, the rare earth isopentyl, butylene or butadiene rubber glue produced can carry a certain amount of solvent. Through flash evaporation technology, these solvents can be effectively removed and solvent mixture can be obtained simultaneously. This process not only contributes to the separation of solvent, but also makes the glue condensed into a more suitable state, which is convenient for subsequent treatment. It should be noted that refining unit 30 is not shown in the accompanying drawings.

[0045] The condensation unit 20 is mainly used to separate more solvent mixture from the polymerization reaction system, further reduce the solvent content in the glue solution, and provide more recycled raw materials for the refining unit 30. The function of the condensation unit 20 is to improve the solvent recovery rate and reduce waste discharge.

[0046] The function of the refining unit 30 is to recover important monomers such as butadiene and isoprene and solvent from the solvent mixture obtained by the flash evaporation and condensation unit 20. After being refined, these recovered substances will be sent back to the polymerization unit 10 to continue to participate in the reaction process. On the one hand, the cost of raw materials is saved, and on the other hand, environmental pollution is reduced, which meets the requirements of green manufacturing.

[0047] In some embodiments of the present application, in the refining unit 30, when preparing butadiene rubber, the solvent mixture is sent to the butadiene recovery tower 31 to recover the butadiene monomer, and the kettle liquid of the butadiene recovery tower 31 is sent to the solvent washing tower to start the solvent refining process; and / or when preparing isoprene rubber, the solvent mixture is sent to the isoprene recovery tower 34 to recover the isoprene monomer, and the kettle liquid of the isoprene recovery tower 34 is sent to the solvent washing tower to start the solvent refining process; and / or when preparing butadiene-pentene rubber, the solvent mixture is sent to the butadiene recovery tower 31 to recover the butadiene monomer, the kettle liquid of the butadiene recovery tower 31 is sent to the isoprene recovery tower 34 to recover the isoprene monomer, and the kettle liquid of the isoprene recovery tower 34 is sent to the solvent washing tower to start the solvent refining process.

[0048] The butadiene recovery tower 31 is used to recover the butadiene monomer produced in the production process of cis-1,4-butadiene rubber or butadiene-pentadiene rubber, and after recovery, the waste of raw materials can be reduced and the utilization efficiency of the monomer can be improved. The isoprene recovery tower 34 is used to recover the isoprene monomer in the production process of isoprene rubber or butadiene-pentadiene rubber, and these recovered monomers can be used again in polymerization reaction to improve the utilization rate of raw materials. Through the solvent washing tower, the kettle liquid in the recovery tower is further refined, and the insoluble substances and water-soluble impurities in the solvent are removed, so that the recovered solvent can be safely reused.

[0049] like Figure 2As shown, specifically, when producing butadiene rubber, the recovered solvent from the flash tank 21 and the condensation unit 20 will be directly sent to the butadiene recovery tower 31 for recovering butadiene monomer, and the kettle liquid will be sent to the solvent washing tower through the kettle liquid pump to start the solvent refining process. When producing isoprene rubber, the recovered solvent from the flash tank 21, the blending tank 22 and the condensation unit 20 will be sent to the isoprene recovery tower 34 through the recovery tank 23 to recover the isoprene monomer, and the kettle liquid will also be sent to the solvent washing tower through the kettle liquid pump to start the solvent refining process. When producing butadiene-pentadiene rubber, the recovered solvent from the flash tank 21, the blending tank 22 and the condensation unit 20 is first sent to the butadiene recovery tower 31 through the recovery tank 23 to recover the butadiene monomer, and then the kettle liquid of the butadiene recovery tower 31 is sent to the isoprene recovery tower 34 through the kettle liquid pump to recover the isoprene monomer, and finally the kettle liquid of the isoprene recovery tower 34 is sent to the solvent washing tower through the kettle liquid pump to start the solvent refining process.

[0050] According to the different types of rubber produced, such as cis-1, 1, 2-butadiene rubber, isoprene rubber or 1, 2-pentane rubber, the recycling process can be flexibly switched to ensure the smooth recovery and refining of different monomers such as butadiene and isoprene to meet different production needs. Through efficient recovery and refining of monomers, the waste of raw materials is reduced and production costs are saved; the recovered solvents and monomers can be reused to avoid excessive dependence on new raw materials.

[0051] In some embodiments of the present application, the solvent mixture enters the drying tower 39 after passing through the butadiene recovery tower 31, the isoprene recovery tower 34 or the solvent washing tower, and then enters the polymerization unit 10; wherein the operating temperature of the drying tower 39 is 10°C-70°C, and the operating pressure of the drying tower 39 is 0.1MPa-1.0MPa.

[0052] like Figure 3 As shown, the purpose of the drying tower 39 is to remove moisture or other volatile organic matter in the solvent mixture to ensure that the solvent entering the polymerization unit 10 is dry and free of impurities, which is crucial to the smooth progress of the polymerization reaction. Different from the traditional drying technology, the present invention precisely controls the temperature and pressure of the drying tower 39 so that the moisture can be efficiently removed at low temperature and appropriate pressure, avoiding the possible degradation of the solvent and the adverse effects of high temperature on the polymerization reaction. The operating temperature of the drying tower 39 is set in the range of 10°C-70°C. Too high a temperature may cause the degradation of the solvent components, while too low a temperature may reduce the drying efficiency. By controlling in this suitable temperature range, it can be ensured that the moisture or impurities in the solvent are effectively removed without damaging its chemical properties. The operating pressure range is 0.1MPa to 1.0MPa. Appropriate pressure helps to improve the drying efficiency of the solvent and avoid potential safety hazards under high pressure.

[0053] like Figure 2As shown, for example, when preparing butadiene rubber, the recovered solvent is separated through a butadiene recovery tower 31. On the one hand, the obtained light components are sequentially passed through a butadiene refining unit 32 and a butadiene drying tower 33, and the butadiene raw material finally obtained enters the polymerization unit 10 again; on the other hand, the obtained heavy components are sequentially passed through a solvent refining unit 37 and a solvent drying tower 38, and the solvent raw material finally obtained enters the polymerization unit 10 again. When preparing isoprene rubber, the recovered solvent is separated through an isoprene recovery tower 34. On the one hand, the obtained light components are sequentially passed through an isoprene refining unit 35 and an isoprene drying tower 36, and the isoprene raw material finally obtained enters the polymerization unit 10 again; on the other hand, the obtained heavy components are sequentially passed through a solvent refining unit 37 and a solvent drying tower 38, and the solvent raw material finally obtained enters the polymerization unit 10 again. When preparing butadiene-pentadiene rubber, the recovered solvent is first separated through a butadiene recovery tower 31. On the one hand, the separated light components are sequentially passed through a butadiene refining unit 32 and a butadiene drying tower 33, and the obtained butadiene raw material enters the polymerization unit 10 again. On the other hand, the separated heavy components enter an isoprene recovery tower 34 for further separation, and the separation and refining steps are the same as those of isoprene rubber.

[0054] Specifically, the oxygen content of the monomer and solvent in the present invention is less than 10ppm, the water content is less than 20ppm, and the content of polymerization impurities such as TBC is less than 10ppm. Through long-term production practice, it is found that polar impurities such as water, oxygen, and TBC will destroy the activity of the rare earth catalyst. To this end, the present invention has re-arranged the refining unit 30, and installed two continuously working dryers, namely activated aluminum adsorption beds, on the material pipeline from the monomer / solvent refining storage tank to the polymerization kettle. The material enters from the bottom of the dryer and is discharged from the top, which can effectively remove impurities such as water, oxygen and TBC in the raw materials, and even reduce the content of these impurities to less than 5ppm, thereby minimizing the impact of impurities on the rare earth catalyst and protecting the active center of the rare earth catalyst from being destroyed. In this way, the amount of rare earth catalyst used can be reduced, while keeping the conversion rate always higher than 95%, and showing the active polymerization characteristics of no chain termination; that is, after adding new monomers, the polymerization reaction can continue, and the reaction rate does not decrease. The operating temperature of the drying tower 39 is 10°C-70°C, the operating pressure is 0.1MPa-1.0MPa, and the residence time is controlled according to the concentration level of impurities, and in this embodiment is controlled between 0.1h-3.0h. The activated aluminum in the drying tower 39 can be regenerated and reused, so no solid waste is generated.

[0055] In some embodiments of the present application, the flexible switching production equipment also includes a post-processing unit 40, which is arranged after the condensation unit 20. The post-processing unit 40 includes extrusion dehydration treatment, expansion drying treatment, and fluidized bed drying treatment in sequence.

[0056] like Figure 2 As shown, the water in the material is removed by extrusion to achieve the purpose of dehydration. The water is further removed by expansion, usually using the temperature and pressure difference to expand the material and accelerate the evaporation of water. Finally, the material is dried by fluidized bed technology to fully evaporate the water on its surface to achieve the effect of drying. The condensation unit 20 performs preliminary polymerization or mixing treatment on the material, but the material still needs to be post-processed to reach the final product specifications. By combining different dehydration and drying steps, the water in the material can be removed more efficiently, thereby shortening the production cycle and improving production efficiency.

[0057] In some embodiments of the present application, the polymerization unit 10 includes a first static mixer 15a and a second static mixer 15b; the monomer and the solvent enter the first static mixer 15a for premixing to obtain a premix, and the premix and the rare earth catalyst enter the second static mixer 15b for mixing to obtain a mixed liquid.

[0058] like Figure 1 As shown, during the polymerization reaction, the main function of the first static mixer 15a is to perform preliminary mixing of the monomer and the solvent to form a uniform premix; the mixing of the premix can ensure sufficient contact between the monomer and the solvent, avoid non-uniformity during the reaction, and thus provide an ideal mixing basis for the subsequent polymerization reaction. The premix and the rare earth catalyst are further mixed after entering the second static mixer 15b; the addition of the rare earth catalyst is a key chemical factor in the polymerization reaction, and the second static mixer 15b ensures sufficient mixing of the catalyst and the premix so that the catalyst is evenly distributed in the polymerization reaction to promote the reaction.

[0059] Specifically, all monomer feed ports and the solvent main line are combined at the front end of the first static mixer 15a, and after being fully premixed in the first static mixer 15a, they are combined with the rare earth catalyst feed port 14, and then further mixed in the second static mixer 15b, and finally enter the polymerization first kettle 11a to start the polymerization process. Different components of the rare earth catalyst (such as neodymium source, aluminum source, chlorine source and silicone oil) can be selectively combined with the monomer / solvent main line on the pipeline between the first static mixer 15a and the second static mixer 15b, and can also be combined with the main material pipeline in the form of aging liquid on the pipeline between the two static mixers.

[0060] By dividing the mixing of monomers, solvents and catalysts into two stages, the mixing accuracy can be better controlled. The step-by-step mixing of the static mixer can ensure that the rare earth catalyst and the premix are fully in contact and reacted, thereby improving the efficiency of the polymerization reaction, reducing side reactions, and increasing the yield of the product. Compared with traditional mechanical stirring equipment, the static mixer has lower energy consumption and more stable operating performance. It does not require an external power device for stirring, so it can reduce overall energy consumption, while reducing equipment wear and improving equipment operation stability and service life.

[0061] An embodiment of the present invention further provides a flexible switching production device, which adopts the flexible switching production process as described above.

[0062] Flexible switching production equipment can flexibly switch between different production modes. Flexible switching production equipment not only includes the physical equipment itself, but also covers the intelligent switching of operating processes. Combined with the application of flexible switching production processes, this equipment can adjust the production method, control parameters and reaction conditions according to specific needs during the production process, thereby achieving an efficient and accurate production process.

[0063] The versatility of flexible switching production equipment can greatly reduce the investment cost of production equipment. In addition, equipment that can quickly switch production modes helps improve production efficiency, reduce switching time and unnecessary downtime, thereby reducing production costs.

[0064] It should be noted that, in addition to butadiene and isoprene, rare earth catalysts can also catalyze the coordination polymerization of many conjugated dienes such as styrene, β-myrcene and trans-β-farnesene to obtain synthetic rubbers with different structures and properties. Furthermore, any one or several of the above-mentioned monomers can also use the flexible switching production equipment of this embodiment, and technicians in this field can adjust the relevant process parameters according to actual conditions. The combination of this equipment and process can achieve efficient and diversified rubber production, meet different product requirements, and improve production flexibility and efficiency.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A flexible switching production process for rare earth isopentyl, butylene and butadiene rubbers, characterized in that: The flexible switching production process is carried out in a flexible switching production device, the flexible switching production device includes a polymerization unit and a coagulation unit, and the flexible switching production process includes the following steps: Mixing monomers, solvents and rare earth catalysts to obtain a mixed solution; adding the mixed solution to a polymerization unit for polymerization reaction to obtain rare earth isopentyl, butylene-pentyl or cis-1,2-butadiene rubber solution; then introducing the rare earth isopentyl, butylene-pentyl or cis-1,2-butadiene rubber solution into a coagulation unit for coagulation to obtain rare earth isopentyl, butylene-pentyl or cis-1,2-butadiene rubber; Wherein, the monomer includes at least one of butadiene and isoprene; The polymerization unit comprises a first kettle, a middle kettle and a last kettle, and branching agent feeding ports are arranged on the pipeline between the first kettle and the middle kettle, the 25% / 50% / 75% liquid level of the middle kettle, and the pipeline between the middle kettle and the last kettle.

2. The flexible switching production process according to claim 1, characterized in that: The branching agent includes silicon tetrachloride, germanium tetrachloride, tin tetrachloride and alkyl trichlorides thereof; and / or The amount of the branching agent added is 0.01wt%-0.15wt% of the monomer; and / or The branching agent is fed into the polymerization unit to start the branching reaction when the polymerization reaction conversion rate reaches 60%-100% and the Mooney value of the glue solution reaches 15-50 (ML 100℃ 1+4); and / or The solvent includes at least one of n-hexane, n-pentane, cyclopentane, cyclohexane, n-heptane, benzene and toluene.

3. The flexible switching production process according to claim 1, characterized in that: The feed temperature of the mixed solution is -10°C-70°C; The bottom temperature of the first kettle is 0°C-70°C, and the top temperature of the first kettle is 70°C-100°C; The bottom temperature of the middle kettle is 80°C-100°C, and the top temperature of the middle kettle is 85°C-100°C; The bottom temperature of the final kettle is 90°C-100°C, and the top temperature of the final kettle is 90°C-95°C; The gas phase pressure of the polymerization unit is 0.1MPa-1.0MPa, and the residence time of the glue in the polymerization unit is 40min-180min.

4. The flexible switching production process according to claim 1, characterized in that: The discharge pipeline of the final kettle is provided with a feeding port for a terminator, wherein the terminator comprises at least one of isooctyl alcohol, tetrahydrofurfuryl alcohol and menthol, and the addition amount of the terminator is 1wt%-5wt% of the monomer; and / or The discharge pipeline of the final kettle is provided with a feeding port for an antioxidant, wherein the antioxidant comprises at least one of a hindered phenol antioxidant and a hindered amine antioxidant, and the addition amount of the antioxidant is 0.1wt%-1.0wt% of the glue solution; and / or The discharge pipeline of the final kettle is provided with a feeding port for a viscosity reducing agent, wherein the viscosity reducing agent comprises at least one of fatty acid and paraffin oil, and the added amount of the viscosity reducing agent is 0.1wt%-1.0wt% of the glue solution.

5. The flexible switching production process according to claim 1, characterized in that: The flexible switching production equipment also includes a refining unit; a solvent mixture obtained by flashing the rare earth isopentyl, butadiene-pentyl or butadiene rubber solution obtained by the polymerization reaction, and a solvent mixture obtained by the condensation unit are sent to the refining unit; and the butadiene, isoprene and solvent recovered by the refining unit are sent to the polymerization unit.

6. The flexible switching production process according to claim 5, characterized in that: In the refining unit, When preparing butadiene rubber, the solvent mixture is sent to a butadiene recovery tower to recover butadiene monomer, and the kettle liquid of the butadiene recovery tower is sent to a solvent washing tower to start a solvent refining process; and / or When preparing isoprene rubber, the solvent mixture is sent to an isoprene recovery tower to recover the isoprene monomer, and the kettle liquid of the isoprene recovery tower is sent to a solvent washing tower to start a solvent refining process; and / or When preparing butadiene-pentadiene rubber, the solvent mixture is sent to a butadiene recovery tower to recover butadiene monomer, the kettle liquid of the butadiene recovery tower is sent to an isoprene recovery tower to recover isoprene monomer, and the kettle liquid of the isoprene recovery tower is sent to a solvent washing tower to start the solvent refining process.

7. The flexible switching production process according to claim 6, characterized in that: The solvent mixture passes through a butadiene recovery tower, an isoprene recovery tower or a solvent washing tower, enters a drying tower, and then enters a polymerization unit; Wherein, the working temperature of the drying tower is 10°C-70°C, and the operating pressure of the drying tower is 0.1MPa-1.0MPa.

8. The flexible switching production process according to claim 1, characterized in that: The flexible switching production equipment also includes a post-processing unit, which is arranged after the condensation unit. The post-processing unit includes extrusion dehydration treatment, expansion drying treatment, and fluidized bed drying treatment in sequence.

9. The flexible switching production process according to claim 1, characterized in that: The polymerization unit comprises a first static mixer and a second static mixer; the monomer and the solvent enter the first static mixer for premixing to obtain a premix, and the premix and the rare earth catalyst enter the second static mixer for mixing to obtain the mixed liquid.

10. A flexible switching production equipment, characterized in that: The flexible switching production equipment adopts the flexible switching production process as described in any one of claims 1-9.

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