Device and method for continuous polymerization of rubber solution to produce engineering plastics

Abstract

The application provides a device and method for continuously polymerizing rubber glue solution to produce engineering plastics, and the device comprises: a glue solution direct conveying system, which is provided with a polymerization kettle; a premixing unit, which comprises a dynamic mixer and a premixing kettle; and a solvent recovery system, which comprises a devolatilization tower and an azeotropic rectification tower; wherein the polymerization kettle is directly connected with the premixing unit through an insulation pipeline. Through the technical means of directly using the glue solution for ABS or HIPS polymerization production and refining and recovering cyclohexane solvent, the problems of high energy consumption, low efficiency, complex process and environmental pollution in the traditional process can be overcome.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of styrene-based resin, in particular to a device and method for producing engineering plastics by continuous polymerization of rubber glue solution. BACKGROUND

[0002] Acrylonitrile butadiene styrene copolymer (ABS) is widely used in the fields of construction, transportation, communication, household appliances, electronics, daily necessities, etc. as a general plastic. High fracture toughness is one of the decisive factors for the wide application of ABS resin. The structure of the polymer determines its performance. The butadiene component endows ABS resin with toughness and low-temperature resistance, and the low-temperature resistance further enhances the impact performance. Therefore, the main factors affecting the impact performance of ABS resin are the composition and structural parameters of the rubber phase. Therefore, the selection of toughening rubber is a key technology in the synthesis and research of ABS resin. In the preparation of high impact polystyrene resin (HIPS) and ABS, the conventional rubber selected as a toughening agent can be low-cis polybutadiene rubber, high-cis polybutadiene rubber, butadiene-isoprene copolymer, solution-polymerized butadiene-styrene rubber, and styrene-butadiene-styrene copolymer.

[0003] Continuous bulk polymerization is one of the main processes for producing HIPS and ABS resin. It involves adding heated rubber into acrylonitrile, styrene, and part of the solvent, and then adding appropriate amount of modifiers and initiators, etc. to complete graft polymerization. The production principle is that acrylonitrile and styrene copolymer belong to the continuous phase, and the grafted rubber particles belong to the dispersed phase. After granulation and devolatilization, the final resin product is obtained. However, the continuous bulk polymerization process is relatively complex. To fully integrate the rubber into the monomer mixture, the polymerization process must be well controlled, and the rubber particle size, rubber dosage, and type, grafting rate, etc. also need to be strictly controlled.

[0004] In the traditional continuous bulk method for preparing ABS or HIPS, solid polybutadiene rubber or styrene-butadiene rubber is generally used as raw material, which needs to go through a long pretreatment process of "rubber synthesis-solvent drying-pulverization-dissolution". In the rubber synthesis process, cyclohexane and other solvents are used, which need to be removed by high-temperature drying. The energy consumption accounts for 30%, and the solvent recovery rate is only 70%~75%. After drying, the rubber needs to be dissolved in styrene / acrylonitrile monomer again, and ethylbenzene needs to be added as a diluent, resulting in a solvent comprehensive utilization rate of less than 60%, and introducing mechanical impurities with a particle size non-uniformity of more than 40%. The drying process needs to heat the rubber to 120℃~150℃, which accounts for more than 30% of the total energy consumption. Dust pollution generated in the pulverization process requires supporting dust removal equipment, further increasing the investment and operating cost.

[0005] Therefore, the problems of solvent compatibility, high energy consumption, and green production in the continuous bulk method for producing HIPS and ABS need to be solved. SUMMARY

[0006] To solve the above problems, the application provides a device and method for continuously polymerizing rubber glue solution to produce engineering plastics, aiming to overcome the technical problems of high energy consumption, low efficiency, complex process and environmental pollution in traditional processes through innovative technical means such as direct coupling process of glue solution, solvent closed loop utilization and dispersion strengthening mechanism.

[0007] The application provides a device for continuously polymerizing rubber glue solution to produce engineering plastics, comprising:

[0008] A glue solution direct feeding system is provided with a polymerization kettle.

[0009] A premixing unit comprises a dynamic mixer and a premixing kettle.

[0010] A solvent recovery system comprises a devolatilization tower and a azeotropic distillation tower.

[0011] The polymerization kettle is directly connected to the premixing unit through an insulation pipeline.

[0012] Further, the thickness of the insulation layer of the insulation pipeline is 50mm, and the temperature control is 40℃-50℃.

[0013] Further, the glue solution direct feeding system further comprises a glue solution buffer tank, which is arranged between the polymerization kettle and the premixing unit, and is used to match the rate of polymerization reaction.

[0014] Further, the premixing kettle comprises:

[0015] When the glue solution of low cis-polybutadiene rubber is used as raw material, the temperature of the first premixing kettle is 60℃-70℃, the pressure is 0.9MPaG, and the stirring rate is 30rpm-40rpm; when the glue solution of solution-polymerized styrene-butadiene rubber is used as raw material, the temperature of the first premixing kettle is 65℃-75℃, the pressure is 0.8MPaG, and the stirring rate is 40rpm-50rpm.

[0016] When the glue solution of low cis-polybutadiene rubber is used as raw material, the temperature of the second premixing kettle is 100℃-110℃, the pressure is 0.85MPaG, and the stirring rate is 50rpm-60rpm; when the glue solution of low cis-polybutadiene rubber is used as raw material, the temperature of the second premixing kettle is 110℃-120℃.

[0017] Further, the dynamic mixer comprises:

[0018] A first high-speed shearing unit is used for rapid and uniform mixing of polymerization glue solution and polar monomers such as styrene and acrylonitrile.

[0019] The secondary static mixing unit is used for further realizing uniform dispersion and mixing of the polymer glue liquid and polar monomers such as styrene and acrylonitrile.

[0020] The tertiary ultrasonic oscillation unit is used for promoting micron-level dispersion of the polar monomer acrylonitrile in the glue liquid.

[0021] Further, the premixing unit comprises a multistage polymerizer, and the multistage polymerizer comprises at least two reactors connected in series, and the temperature gradient is controlled to be 110 DEG C to 160 DEG C.

[0022] Further, when the low-cis polybutadiene rubber glue liquid is used as the raw material, the operating temperature of the devolatilization tower is 120 DEG C to 130 DEG C, and the pressure is 0.5 MPaG; when the solution polymerized styrene-butadiene rubber glue liquid is used as the raw material, the operating temperature of the devolatilization tower is 160 DEG C, and the pressure is 0.4 MPaG.

[0023] Further, the azeotropic rectification tower is provided with a solvent heat circulation loop, which is used for preheating the rectification feed by using the polymerization residual heat.

[0024] The application further provides a method for continuously polymerizing rubber glue liquid to produce engineering plastics, which comprises the following steps: synthesizing rubber; performing a solvent loss-free polymerization reaction by using the rubber glue liquid as a raw material; and recycling the solvent in a closed loop, wherein the rubber glue liquid is at least one of solution polymerized styrene-butadiene rubber and low-cis polybutadiene rubber.

[0025] Further, the synthesis parameters of the rubber glue liquid comprise:

[0026] When the glue liquid of the low-cis polybutadiene rubber is prepared, the catalyst is n-butyl lithium, the concentration is 1.5 mol / L to 2.0 mol / L, the amount is 0.5 ‰ to 1.0 ‰, the polymerization temperature is 80 DEG C ± 5 DEG C, the pressure is 0.6 MPaG, and the reaction time is 4 h to 5 h;

[0027] When the glue liquid of the solution polymerized styrene-butadiene rubber is prepared, the catalyst is n-butyl lithium, the concentration is 1.5 mol / L to 2.0 mol / L, the amount is 0.5 ‰ to 1.0 ‰, the synthesis temperature is 50 DEG C to 65 DEG C, the pressure is 0.3 MPaG to 0.5 MPaG, and the reaction time is 4 h to 6 h.

[0028] Further, the parameters of the polymerization reaction comprise:

[0029] When the low-cis polybutadiene rubber glue liquid is used as the raw material, the low-cis polybutadiene rubber glue liquid accounts for 25% to 35% of the total mass of the glue liquid, the styrene accounts for 45% to 55% of the total mass of the glue liquid, the acrylonitrile accounts for 10% to 15% of the total mass of the glue liquid, the dispersant accounts for 1% to 2% of the total mass of the glue liquid, and the initiator accounts for 0.05% to 0.1% of the total mass of the glue liquid; the dispersant is sorbitol anhydride oleate, and the initiator is di-tert-butyl peroxide.

[0030] When taking the solution polymerized styrene-butadiene rubber glue liquid as raw material, the solution polymerized styrene-butadiene rubber glue liquid accounts for 30% to 40% of the total mass of the glue liquid, styrene accounts for 50% to 60% of the total mass of the glue liquid, acrylonitrile accounts for 10% to 15% of the total mass of the glue liquid, and the chemical additive accounts for 0.2% to 0.5% of the total mass of the glue liquid; the chemical additive includes an initiator, a chain transfer agent and an antioxidant.

[0031] After the technical scheme of the present application is adopted, the following technical effects can be achieved:

[0032] 1. The synthetic glue liquid is directly input into the premixing unit through the heat preservation pipeline, the processes such as solvent drying, crushing and dissolving are cancelled, the processes are seamlessly connected, the process time is shortened to 6h, and the equipment investment is reduced by 25%.

[0033] 2. The premixing unit after optimization can improve the dispersion degree of the glue particles through the three-stage shearing dynamic mixer, namely high-speed shearing, static mixing and ultrasonic oscillation, can disperse the solution polymerized styrene-butadiene rubber glue liquid to 20μm to 30μm, and can improve the grafting site exposure rate by 70%, thereby improving the low-temperature toughness of the ABS resin.

[0034] 3. The solvent recovery system takes cyclohexane as the polymerization reaction medium, and the solvent recovery rate is increased to 99.5% through the three-stage recovery system of the pre-devolatilization tower and the azeotropic distillation tower. The unit product energy consumption is reduced by 41.7%, the process time is reduced by 40%, and the equipment investment is reduced by 27.3%. BRIEF DESCRIPTION OF DRAWINGS

[0035] Figure 1 It is a structural schematic view of the device for continuously polymerizing rubber glue liquid to produce engineering plastics.

[0036] MARKS FOR EXPLANATION:

[0037] 01-glue liquid direct feeding system; 02-premixing unit; 03-solvent recovery system; 11-polymerization kettle; 12-glue liquid buffer tank; 13-heat preservation pipeline; 21-dynamic mixer; 22-first premixing kettle; 23-second premixing kettle; 24-multistage polymerizer; 31-devolatilization tower; 32-azeotropic distillation tower. DETAILED DESCRIPTION

[0038] In order to make the above-mentioned purpose, features and advantages of the present application more obvious and easy to understand, the technical scheme in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the present application.

[0039] In the traditional continuous bulk method for preparing ABS or HIPS, solid polybutadiene rubber or styrene-butadiene rubber is used as raw material, and after synthesis, it needs to go through the pretreatment process of solvent drying, crushing and re-dissolving, which not only leads to a long process, increases the process time, but also consumes a large amount of energy in the solvent drying process, and the energy consumption accounts for as high as 30%. Using cyclohexane as the rubber synthesis solvent, it needs to be removed by high temperature during drying, and the solvent recovery rate can only reach 70%~75%, and additional ethylbenzene needs to be added when the rubber is re-dissolved in styrene / acrylonitrile monomer, resulting in a comprehensive utilization rate of solvent less than 60%. The rubber in the crushing process will produce mechanical impurities of different particle sizes, and the particle size non-uniformity rate is more than 40%, and the dust pollution generated in the crushing process needs to be treated by additional dust removal equipment, which increases the investment and operating cost.

[0040] To solve the above problems, the embodiment of the present application provides a device for continuously polymerizing rubber solution to produce engineering plastics, which comprises: a rubber solution direct feeding system 01, the rubber solution direct feeding system 01 is provided with a polymerization kettle 11; a premixing unit 02, the premixing unit 02 is provided with a dynamic mixer 21 and a premixing kettle; a solvent recovery system 03, comprising a devolatilization tower 31 and a azeotropic distillation tower 32; wherein the polymerization kettle 11 is connected with the premixing unit 02 through an insulation pipeline 13.

[0041] Firstly, the synthesis of rubber solution is completed in the polymerization kettle 11 of the rubber solution direct feeding system 01.

[0042] Specifically, when preparing the rubber solution of low-cis polybutadiene rubber, the polymerization kettle 11 is made of acid-resistant material, preferably glass lining material, with a volume of 30m³, a jacket temperature control of 80℃~90℃, an internal anchor agitator, and the rotation speed of the anchor agitator is 60rpm. At this time, the polymerization kettle 11 is equipped with styrene and acrylonitrile monomer drop pipelines, and the accuracy of the metering pump is ±0.3%.

[0043] Further, when preparing the rubber solution of low-cis polybutadiene rubber, the insulation pipeline 13 is made of stainless steel 304 material, with an insulation layer thickness of 30mm, a temperature control of 60℃~70℃, to prevent the polymerization system from condensing, and a rotor flowmeter with a range of 0m³ / h~5m³ / h and a pressure sensor with a range of 0MPa~0.8MPa are arranged in the pipeline.

[0044] Specifically, when preparing the rubber solution of solution-polymerized styrene-butadiene rubber, the polymerization kettle 11 is made of alkane-resistant material, preferably stainless steel 316L material, with a volume of 50m³, and the outlet of the polymerization kettle 11 is directly connected with the ABS premixing unit through the insulation pipeline 13.

[0045] Further, when preparing the solution polymerized butadiene rubber, the thickness of the heat preservation pipeline 13 is 50 mm, and the temperature is controlled between 40°C and 50°C. The electromagnetic flow meter and pressure sensor are arranged in the heat preservation pipeline 13. The accuracy of the flow meter is ±0.5%, and the range of the sensor is 0MPa-1MPa.

[0046] The design of the polymerization kettle 11 fully considers the stability and safety of the material in the synthesis process. Different materials are selected for the synthesis of different rubbers, which not only ensures the corrosion resistance and high temperature resistance of the polymerization kettle 11, but also ensures the purity of the material in the synthesis process, avoiding the mixing of impurities due to material problems. It not only meets the demand of large-scale production, but also ensures the continuity and stability of the synthesis process.

[0047] The heat preservation pipeline 13 effectively reduces the heat loss of the material in the conveying process, and improves the energy utilization rate. The appropriate temperature control range not only ensures the fluidity of the material in the conveying process, but also avoids the deterioration of the material or the increase of energy consumption due to too high or too low temperature. The configuration of the electromagnetic flow meter and the pressure sensor realizes the accurate monitoring of the material flow and the pressure, and provides strong support for the automatic control and optimization of the production process.

[0048] Further, when preparing the solution polymerized butadiene rubber, the thickness of the heat preservation pipeline 13 is 50 mm, and the temperature is controlled between 40°C and 50°C. The electromagnetic flow meter and pressure sensor are arranged in the heat preservation pipeline 13. The accuracy of the flow meter is ±0.5%, and the range of the sensor is 0MPa-1MPa.

[0049] Further, when preparing the solution polymerized butadiene rubber, the thickness of the heat preservation pipeline 13 is 50 mm, and the temperature is controlled between 40°C and 50°C. The electromagnetic flow meter and pressure sensor are arranged in the heat preservation pipeline 13. The accuracy of the flow meter is ±0.5%, and the range of the sensor is 0MPa-1MPa.

[0050] The PLC and the distributed control system can monitor the key parameters such as flow and pressure in real time, and can also automatically adjust the matching ratio according to the production demand, so as to greatly improve the production efficiency and product quality. In addition, such linkage design also makes the whole production process more automatic and intelligent, reduces manual intervention, and reduces the operation difficulty and cost.

[0051] In some embodiments of the present application, the glue solution direct feeding system further comprises a glue solution buffer tank 12, which is arranged between the polymerization kettle 11 and the premixing unit, and is used to match the synthesis rate with the polymerization rate.

[0052] Specifically, when the glue solution of low-cis polybutadiene rubber is used as raw material, the volume of glue solution buffer tank 12 is 5 cubic meters, equipped with nitrogen protection system, set liquid level interlocking device, buffer time ≤20 minutes. When the glue solution of solution polymerized styrene-butadiene rubber is used as raw material, the volume of glue solution buffer tank 12 is 10 cubic meters, equipped with nitrogen protection system, the glue solution buffer tank 12 is set between the synthesis process and the polymerization process to play a buffering role, and the buffer time is ≤30 minutes.

[0053] This design ensures that the production bottleneck problem caused by rate mismatch between the synthesis and polymerization processes is effectively alleviated. The existence of glue solution buffer tank 12 enables the glue solution produced by the synthesis process to be temporarily stored, and avoids production stagnation caused by deviation of the processing speed of the polymerization process. In addition, the buffer time of less than half an hour not only ensures the continuity of the production process, but also avoids the quality problems that may occur due to long-term storage of the glue solution during temporary storage.

[0054] In some embodiments of the present application, the premixing kettle includes a first premixing kettle 22 and a second premixing kettle 23. When the glue solution of low-cis polybutadiene rubber is used as raw material, the temperature of the first premixing kettle 22 is 60-70°C, the pressure is 0.9 MPaG, and the stirring rate is 30-40 rpm; when the glue solution of solution polymerized styrene-butadiene rubber is used as raw material, the temperature of the first premixing kettle 22 is 65-75°C, the pressure is 0.8 MPaG, and the stirring rate is 40-50 rpm. When the glue solution of low-cis polybutadiene rubber is used as raw material, the temperature of the second premixing kettle 23 is 100-110°C, the pressure is 0.85 MPaG, and the stirring rate is 50-60 rpm; when the glue solution of solution polymerized styrene-butadiene rubber is used as raw material, the temperature of the second premixing kettle 23 is 110-120°C.

[0055] Specifically, when the glue solution of low-cis polybutadiene rubber is used as raw material, the operating conditions of the first premixing kettle 22 are set to a temperature of 60-70°C, at which the polymerization system remains liquid, a pressure of 0.9 MPaG, and a stirring rate of 30-40 rpm, and the low-cis polybutadiene rubber glue solution is dispersed to 40-50 μm. The second premixing kettle 23 is heated to a temperature of 100-110°C, which is lower than the boiling point of the polymerization system 110.6°C, a pressure of 0.85 MPaG, and a stirring rate of 50-60 rpm, and the free radical graft polymerization of styrene and acrylonitrile monomers on the rubber molecular chain is started, and the monomer conversion rate is controlled to 20-25%.

[0056] Specifically, when the solution polymerized styrene-butadiene rubber is used as the raw material, the operating conditions of the first premixing kettle 22 are set to a temperature of 65-75°C, at which the cyclohexane remains in a liquid state, ensuring that the solution polymerized styrene-butadiene rubber can be uniformly dispersed therein. Meanwhile, the pressure of 0.8 MPaG and the stirring rate of 40-50 rpm work together to ensure that the dispersion size of the solution polymerized styrene-butadiene rubber is accurately controlled to be between 20-30 μm, which provides good initial conditions for the subsequent polymerization reaction. The second premixing kettle 23 is heated to a temperature of 110-120°C, at which the cyclohexane is partially vaporized, and the vaporization rate is maintained at 20-30%. This design utilizes the latent heat effect of the vaporization of the solvent to absorb the heat generated during the polymerization reaction, accounting for 40% of the total heat absorption, effectively reducing the demand for external cooling of the system. Meanwhile, the cooling load of the jacket is reduced by 60%, significantly improving the energy utilization efficiency and reducing the production cost.

[0057] In some embodiments of the present application, the dynamic mixer 21 comprises: a first high-speed shearing unit for rapidly and uniformly mixing the polymerization glue solution with polar monomers such as styrene and acrylonitrile; a second static mixing unit for further uniformly dispersing and mixing the polymerization glue solution with the polar monomers such as styrene and acrylonitrile; and a third ultrasonic oscillation unit with an oscillation frequency of 20 kHz for promoting the micron-level dispersion of the polar monomer acrylonitrile in the glue solution.

[0058] Specifically, when the solution polymerized styrene-butadiene rubber is used as the raw material, the first high-speed shearing unit is a serrated rotor with a rotation speed of 1500 rpm, which can break the solution polymerized styrene-butadiene rubber to a size of less than 50 μm. A cooling jacket is provided to control the temperature to be less than or equal to 70°C, so as to avoid the volatilization of the styrene and acrylonitrile monomers. The second static mixing unit comprises 9 groups of Kenics mixing elements arranged alternately in a left-handed / right-handed manner, which can promote the formation of a stable emulsion of the solution polymerized styrene-butadiene rubber and the styrene / acrylonitrile. In addition, sorbitan oleate dispersant needs to be additionally injected, and the addition amount of the metering pump is 1-2 kg / h.

[0059] Specifically, when the solution polymerized styrene-butadiene rubber is used as the raw material, the dynamic mixer 21 works through the cooperation of the three shearing units to ensure the efficiency of the mixing process and the quality of the mixture. First, the first high-speed shearing unit operates at a rotation speed of 2000 rpm, which mainly functions to break the glue solution into micron-sized liquid beads and uniformly disperse them in the styrene and acrylonitrile monomers, laying a foundation for the subsequent mixing steps. Subsequently, the second static mixing unit, i.e., the Kenics mixing element, is involved, which realizes the uniformization of the phase distribution through a series of static mixing channels, ensuring that the components in the mixture are fully and uniformly mixed. Finally, the third ultrasonic oscillation unit oscillates at a frequency of 20 kHz, which helps the glue solution to be micron-sized dispersed in the styrene and acrylonitrile monomers.

[0060] In some embodiments of the present application, the premixing unit comprises a multi-stage polymerizer 24, which comprises at least two reactors connected in series, and the temperature gradient is controlled to be 110-160°C.

[0061] Specifically, when the raw material is the solution of low-cis polybutadiene rubber, the multi-stage polymerizer 24 is composed of three PFRs connected in series, each with a volume of 8 m3, and the total effective volume is 24 m3. The inner wall is coated with a polytetrafluoroethylene coating to reduce the adhesion of high-viscosity solution. It is equipped with a jacketed circulating heat conduction oil system, and the temperature is controlled to be 110-150°C. Each reactor is provided with an independent stirring paddle, which is a combination of an anchor and a turbine, and the rotating speed is 10-20 rpm to promote the radial mixing of the material.

[0062] Preferably, when the raw material is the solution of low-cis polybutadiene rubber, the temperature of the first-stage polymerizer is 110°C, the pressure is 0.8 MPaG, the residence time is 1.5 h, and the conversion rate is increased to 65%; the temperature of the second-stage polymerizer is 130°C, the pressure is 0.7 MPaG, the residence time is 1.5 h, and the conversion rate is increased to 85%; the temperature of the third-stage polymerizer is 150°C, the pressure is 0.6 MPaG, the residence time is 2 h, and the final conversion rate is ≥99.5%.

[0063] Specifically, when the raw material is the solution of solution-polymerized styrene-butadiene rubber, two-stage reactors are used. The temperature of the first-stage polymerizer is 130°C, which is used to initiate the free radical graft polymerization of styrene and acrylonitrile on the molecular chain of solution-polymerized styrene-butadiene rubber; the temperature of the second-stage polymerizer is 145°C, which is used to strengthen the free radical graft copolymerization of styrene and acrylonitrile on the molecular chain of solution-polymerized styrene-butadiene rubber, the pressure is 0.7 MPaG, and the residence time is 4-5 h. The grafting rate of this polymerization reaction is ≥95%, the thickness of the grafted layer on the surface of the solution-polymerized styrene-butadiene rubber particles reaches 15-20 nm, and the interfacial adhesion is increased by 40%.

[0064] In some embodiments of the present application, when the raw material is the solution of low-cis polybutadiene rubber, the operating temperature of the devolatilization tower 31 is 120-130°C, and the pressure is 0.5 MPaG; when the raw material is the solution of solution-polymerized styrene-butadiene rubber, the operating temperature of the devolatilization tower 31 is 160°C, and the pressure is 0.4 MPaG.

[0065] Specifically, when the raw material is the solution of low-cis polybutadiene rubber, the devolatilization tower 31 is a plate tower with 30 layers of float valve trays, the operating temperature is 120-130°C, the pressure is 0.5 MPaG, and more than 90% of the polymerization system can be separated. The recovery of the polymerization system is 15-18 kg / 100 kg of solution, the recovery rate is 88-92%, and the steam at the top of the tower is liquefied by a tube condenser, with the cooling water temperature being 25°C. In addition, a scraper-type agitator is provided at the tower bottom to prevent gel deposition.

[0066] Specifically, when the low-cis polybutadiene rubber solution is used as the raw material, the operating temperature of the devolatilization tower 31 is 160°C, and the pressure is 0.4 MPaG, and more than 90% of the cyclohexane can be separated, and the cyclohexane contains a small amount of styrene monomer.

[0067] In some embodiments of the present application, the azeotropic distillation tower 32 is provided with a solvent heat circulation loop for preheating the distillation feed by the polymerization waste heat.

[0068] Specifically, when the low-cis polybutadiene rubber solution is used as the raw material, the packing of the azeotropic distillation tower 32 is ceramic Bauer ring with a specific surface area of 300 m² / m³, the operating pressure is 0.3 MPaG, the tower top temperature is 105°C~110°C, which is the azeotropic temperature of the polymerization system-styrene, and the reflux ratio is 3:1. The styrene and acrylonitrile monomer polymer are periodically discharged from the bottom of the tower, with a frequency of 1 time / day, and the residual amount of styrene and acrylonitrile monomer in the polymerization system is ≤50 ppm, which meets the requirements of low-cis polybutadiene rubber synthesis, and the solvent circulation number is ≥30 times.

[0069] Further, when the low-cis polybutadiene rubber solution is used as the raw material, the azeotropic distillation tower 32 uses the polymerization waste heat of 110°C~120°C to preheat the distillation feed, and is matched with a finned heat exchanger, and the heat exchange efficiency is improved by 20%. The recovered polymerization system is adsorbed by activated carbon to remove the residual styrene and acrylonitrile monomer, and the purity is ≥99.2%, which is recycled to the low-cis polybutadiene rubber polymerization kettle 11.

[0070] Specifically, when the solution-polymerized styrene-butadiene rubber solution is used as the raw material, the packing of the azeotropic distillation tower 32 is stainless steel θ ring with a specific surface area of 500 m² / m³, and the reflux ratio is 5:1 to ensure the optimal separation effect. The overhead product is mainly cyclohexane with a purity of up to 99.8%. The heavy components in the bottom of the tower are mainly styrene dimers, which are discharged at a frequency of ≤1 time / day to maintain the dynamic balance of the materials in the tower and the stability of the distillation effect. The recovered cyclohexane is filtered by a precision filtration technology with a precision of 5μm. The treated cyclohexane can be directly recycled to the solution-polymerized styrene-butadiene rubber polymerization kettle 11, realizing the efficient recycling of the solvent. This method makes the solvent circulation number reach more than 50 times, effectively reducing the impact on the environment.

[0071] Further, taking the preparation of ABS from the solution-polymerized styrene-butadiene rubber solution as an example, the polymerization waste heat of 140°C~150°C is used to preheat the distillation feed, which can save energy by 30%; the plate heat exchanger is used for the overhead condenser, the heat exchange efficiency is improved by 25%, and the solvent recovery rate is improved from 99% to 99.5%.

[0072] After purification by the three-stage recovery system of the devolatilization tower 31 and the azeotropic rectification tower 32, the solvent recycling rate reaches 99.5%, realizing the zero-emission mode of "recycling refined solvent-polymerization reaction medium-circulation utilization".

[0073] The application relates to a method for continuously polymerizing rubber glue to produce engineering plastics, comprising the following steps: synthesizing rubber; performing polymerization reaction on styrene and the rubber glue; and recycling the solvent; wherein the rubber glue is one of solution-polymerized styrene-butadiene rubber and low-cis polybutadiene rubber.

[0074] Specifically, the synthesis parameters of the rubber glue include: when preparing the glue of the low-cis polybutadiene rubber, a catalyst of n-butyl lithium is used, the amount is 0.5‰-1.0‰, the polymerization temperature is 80±5 DEG C, the pressure is 0.6 MPaG, and the reaction time is 4h-5h; when preparing the glue of the solution-polymerized styrene-butadiene rubber, a catalyst of n-butyl lithium is used, the concentration is 1.5mol / L-2.0mol / L, the amount is 0.5‰-1.0‰, the synthesis temperature is 50 DEG C-65 DEG C, the pressure is 0.3 MPaG-0.5 MPaG, and the reaction time is 4h-6h.

[0075] Specifically, the parameters of the polymerization reaction include: when taking the low-cis polybutadiene rubber glue as raw material, the low-cis polybutadiene rubber glue accounts for 25%-35% of the total amount of the glue, styrene accounts for 45%-55% of the total amount of the glue, acrylonitrile accounts for 10%-15% of the total amount of the glue, a dispersant accounts for 1%-2% of the total amount of the glue, and an initiator accounts for 0.05%-0.1% of the total amount of the glue; when taking the solution-polymerized styrene-butadiene rubber glue as raw material, the solution-polymerized styrene-butadiene rubber glue accounts for 30%-40% of the total amount of the glue, styrene accounts for 50%-60% of the total amount of the glue, acrylonitrile accounts for 10%-15% of the total amount of the glue, and a chemical additive accounts for 0.2%-0.5% of the total amount of the glue, wherein the chemical additive includes an initiator, a chain transfer agent and an antioxidant.

[0076] The application will be described in detail through the following examples.

[0077] Example 1

[0078] The example provides a method for continuously polymerizing low-cis polybutadiene rubber glue to produce ABS, and the method specifically comprises the following steps.

[0079] The method of the example mainly comprises three parts: synthesis of low-cis polybutadiene rubber glue, ABS polymerization reaction and solvent recovery.

[0080] 1. Synthesis of low-cis polybutadiene rubber glue

[0081] Add 85 kg of butadiene, 0.5 kg of n-butyllithium, 165 kg of cyclohexane and n-hexane into the polymerization kettle 11, set the temperature in the kettle to 80℃, the pressure to 0.6 MPaG, and react for 4 h to obtain 250 kg of low-cis polybutadiene rubber solution, with a solid content of 34%.

[0082] 2. ABS polymerization reaction

[0083] Crush 250 kg of low-cis polybutadiene rubber solution, 400 kg of styrene and 120 kg of acrylonitrile in the first high-speed shearing unit of the dynamic mixer 21 to 40 μm, and then mix in the second static mixing unit for 10 min to form a stable emulsion.

[0084] The temperature in the first premixing kettle 22 is 65℃. The temperature in the second premixing kettle 23 is 100℃, the pressure is 0.9 MPaG, and the stirring rate is 30 rpm, so that the LCBR is grafted and copolymerized with styrene and acrylonitrile monomers, and the monomer conversion rate is 25%.

[0085] The polymerization process also needs to add 0.2 kg of di-t-butyl peroxide and 5 kg of Span (sorbitan oleate) 80, and the total residence time in the multi-stage polymerizer 24 is 5 h, the temperature gradient is 110℃-130℃, the grafting rate is 85%, and the solvent vaporization accounts for 20% of the heat removal proportion.

[0086] 3. Solvent recovery

[0087] Through the devolatilization tower 31 and the azeotropic distillation tower 32, 160 kg of n-hexane and cyclohexane are recovered, with a recovery rate of 96.9%, and are reused in the synthesis of low-cis polybutadiene rubber.

[0088] The unit product solvent consumption in the solvent recovery link is 2 kg, and the energy consumption is 0.9 kWh / kg.

[0089] The final ABS product has a -20℃ impact strength of 42 kJ / ㎡, a surface gloss of 88%, and a gel impurity content of 0.4%.

[0090] Example 2

[0091] The embodiment provides a method for continuously polymerizing low-cis polybutadiene rubber solution to produce HIPS, which is as follows.

[0092] The method of the embodiment mainly includes three parts: synthesis of low-cis polybutadiene rubber solution, HIPS polymerization reaction and solvent recovery.

[0093] 1. Synthesis of low-cis polybutadiene rubber solution

[0094] The 68 kg of butadiene, 132 kg of n-hexane cyclohexane, 0.5 kg of n-butyllithium were added into the polymerization kettle 11, the temperature in the kettle was set to 80℃, the pressure was 0.6 MPaG, and the reaction was carried out for 4 h to obtain 200 kg of low cis-polybutadiene rubber solution. The solid content of the obtained solution was 34%, and the low cis-polybutadiene rubber was 68 kg, and the n-hexane cyclohexane was 132 kg.

[0095] 2. HIPS polymerization reaction

[0096] The 200 kg of low cis-polybutadiene rubber solution was mixed with 600 kg of styrene in the dynamic mixer 21 for 8 min, and the styrene was dissolved in n-hexane and cyclohexane to form a homogeneous solution, wherein the 200 kg of low cis-polybutadiene rubber solution contained 68 kg of low cis-polybutadiene rubber and 132 kg of n-hexane and cyclohexane solvent.

[0097] The temperature of the outlet material of the first premixing kettle 22 was 50℃, and the viscosity was 150 mPa・s. The temperature of the second premixing kettle 23 was 120℃, the pressure was 0.7 MPaG, the conversion rate of styrene pre-polymerization was 30%, and a low cis-polybutadiene rubber grafted polystyrene core-shell structure was formed.

[0098] The polymerization process also added 0.3 kg of benzoyl peroxide initiator and 0.5 kg of antioxidant, and the temperature of the multi-stage polymerizer 24 was 150℃, the pressure was 0.5 MPaG, the total residence time was 6 h, and the melt flow rate (MFR) was 8 g / 10 min.

[0099] The heat carried away by the vaporization of the polymerization system accounted for 30% of the total heat.

[0100] 3. Solvent recovery

[0101] The operating pressure of the devolatilization tower 31 was -0.09 MPaG, and the temperature was 200℃. 125 kg of n-hexane and cyclohexane were recovered, and the recovery rate was 94.7%. The purity of the solvent refined in the azeotropic rectification tower 32 was 99.5%, and it was reused in the synthesis of low cis-polybutadiene rubber.

[0102] The unit product solvent consumption in the solvent recovery process was 1.5 kg, and the energy consumption was 1.1 kWh / kg.

[0103] The final obtained HIPS had a cantilever beam impact strength of 15 kJ / m 2 , a melt flow rate of 8 g / 10 min, a heat distortion temperature of 85℃, and a yellow index of 8.

[0104] Example 3

[0105] The present embodiment provides a method for continuously polymerizing a solution-polymerized styrene-butadiene rubber solution to produce HIPS, which is as follows:

[0106] The method of the embodiment mainly includes three parts: synthesis of solution polymerized styrene-butadiene rubber glue, HIPS polymerization reaction and solvent recovery.

[0107] 1. Synthesis of solution polymerized styrene-butadiene rubber glue

[0108] 70 kg of butadiene, 30 kg of styrene, 200 kg of cyclohexane and 0.35 kg of n-butyllithium were added into the polymerization kettle 11 as raw materials, the temperature in the kettle was set to 65 ℃, the pressure was set to 0.45 MPaG, and the reaction was carried out for 6 h, thereby obtaining 300 kg of solution polymerized styrene-butadiene rubber glue. The solid content of the obtained glue was 33.3%, 100 kg of solution polymerized styrene-butadiene rubber and 200 kg of cyclohexane.

[0109] 2. HIPS polymerization reaction

[0110] 250 kg of solution polymerized styrene-butadiene rubber glue and 650 kg of styrene were mixed in the dynamic mixer 21 for 5 min, wherein the 250 kg of solution polymerized styrene-butadiene rubber glue contained 83 kg of solution polymerized styrene-butadiene rubber and 167 kg of cyclohexane solvent.

[0111] The particle size of the material at the outlet of the first premixing kettle 22 was 20 μm, and the temperature was 55 ℃. The temperature of the second premixing kettle 23 was 130 ℃, the pressure was 0.8 MPaG, the temperature rise was controlled by using the boiling point of cyclohexane (80.7 ℃), and the heat was taken away by 40% of the solvent vaporization.

[0112] 0.25 kg of di-tert-butyl peroxide and 0.6 kg of antioxidant were further added during the polymerization reaction, the temperature of the multistage polymerizer 24 was 160 ℃, the pressure was 0.6 MPaG, the total residence time was 5 h, the grafting rate was 95%, and the heat was taken away by 50% of the cyclohexane vaporization.

[0113] 3. Solvent recovery

[0114] After the devolatilization tower 31 and the azeotropic rectification tower 32, 160 kg of cyclohexane was recovered, the recovery rate reached 95.8%, the purity was 99.8%, and it was reused for the synthesis of solution polymerized styrene-butadiene rubber.

[0115] The unit product solvent consumption in the solvent recovery link was 0.8 kg, and the energy consumption was 0.75 kWh / kg.

[0116] The final obtained HIPS had a cantilever beam impact strength of 18 kJ / m 2 .

[0117] Example 4

[0118] The embodiment provides a method for producing ABS by continuously polymerizing solution polymerized styrene-butadiene rubber glue, which is specifically as follows:

[0119] The method of the embodiment mainly includes three parts: synthesis of solution polymerized styrene-butadiene rubber glue, ABS polymerization reaction and solvent recovery.

[0120] 1. Synthesis of solution polymerized styrene-butadiene rubber (SBR) latex

[0121] A 60 kg of butadiene, 40 kg of styrene, 200 kg of cyclohexane and 0.3 kg of n-butyllithium were added into a polymerization kettle as raw materials, the temperature in the kettle was set to 60 °C, the pressure was set to 0.4 MPaG, and the reaction was carried out for 5 h to obtain 300 kg of latex. The solid content of the obtained latex was 33.3%, the solution polymerized SBR was 100 kg, and the cyclohexane was 200 kg.

[0122] 2. ABS polymerization reaction

[0123] The 300 kg of latex prepared in the polymerization kettle 11, 500 kg of styrene and 150 kg of acrylonitrile were mixed for 5 min by a dynamic mixer 21, i.e. the latex was dispersed by high-speed shearing, static mixing and ultrasonic oscillation. The first-stage high-speed shearing rotation speed was 2000 rpm, the second-stage static mixing realized uniform distribution of phases, and the third-stage ultrasonic oscillation frequency was 20 kHz. The particle size of the material at the outlet was 25 μm, and the temperature was 55 °C.

[0124] The temperature of the first premixing kettle 22 was set to 65 °C ~ 75 °C to keep the cyclohexane in liquid state, the pressure was set to 0.8 MPaG, and the stirring rate was set to 40 rpm ~ 50 rpm. The temperature of the second premixing kettle 23 was increased to 110 °C ~ 120 °C to partially vaporize the cyclohexane, the vaporization rate was 20% ~ 30%, the latent heat of vaporization was used to absorb the reaction heat, and the demand for external cooling was reduced. The jacket cooling load was reduced by about 60%. 150 kg of acrylonitrile was added during the polymerization reaction, the total residence time of the multi-stage polymerizer 24 was 4 h, the grafting rate was 97%, and the heat carried away by solvent vaporization accounted for 45%.

[0125] 3. Solvent recovery

[0126] The cyclohexane was recovered by the devolatilization tower 31, the operating temperature was 160 °C, the pressure was 0.4 MPaG, and the recovery rate reached 90%. After the azeotropic rectification tower 32, 179 kg of pure cyclohexane was obtained, the purity was 99.8%, and the recovered cyclohexane was directly used in the solution polymerized SBR polymerization kettle after being filtered by a precision filter with a precision of 5 μm.

[0127] The solvent consumption per unit product in the solvent recovery link was 1 kg, and the energy consumption was 0.68 kWh / kg.

[0128] The final obtained ABS had an impact strength of 52 kJ / m 2 at -20 °C, a surface gloss of 93%, and a solvent residue of 0.03%.

[0129] Although the present application has been disclosed with reference to the above embodiments, the application is not limited to the above embodiments. It will be apparent to those skilled in the art that various modifications and changes can be made thereto without departing from the spirit and scope of the application. The scope of the application should be limited only by the appended claims.

Claims

1. A method for continuously polymerizing rubber solutions to produce engineering plastics, implemented using an apparatus for continuously polymerizing rubber solutions to produce engineering plastics, characterized in that... The method for continuous polymerization of rubber adhesive to produce engineering plastics includes the following steps: synthesizing rubber adhesive; carrying out a solvent-free polymerization reaction using the rubber adhesive as raw material; and closed-loop recovery of the solvent. The device includes: A direct delivery system for adhesive liquid, wherein the direct delivery system for adhesive liquid is equipped with a polymerization reactor; The premixing unit includes a dynamic mixer and a premixing kettle. The dynamic mixer includes: a first-stage high-speed shearing unit for rapidly and uniformly mixing the polymer solution with styrene and acrylonitrile polar monomers; a second-stage static mixing unit for uniformly dispersing and mixing the polymer solution with styrene and acrylonitrile polar monomers; and a third-stage ultrasonic oscillation unit with an oscillation frequency of 20kHz for promoting micron-level dispersion of acrylonitrile polar monomers in the polymer solution. Solvent recovery system, including devolatilization column and azeotropic distillation column; The polymerization reactor is directly connected to the premixing unit via an insulated pipe; the insulated pipe is equipped with an electromagnetic flow meter and a pressure sensor. The adhesive direct delivery system also includes an adhesive buffer tank, which is located between the polymerization reactor and the premixing unit.

2. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The insulation layer of the insulated pipe is 50mm thick, and the temperature of the insulated pipe is controlled at 40℃~50℃.

3. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The premixing vessel includes: In the first premixing vessel, when the polymer solution of low-cis polybutadiene rubber is used as raw material, the temperature of the first premixing vessel is 60℃~70℃, the pressure is 0.1MPaG, and the stirring speed is 30rpm~40rpm; when the polymer solution of solution-polymerized styrene-butadiene rubber is used as raw material, the temperature of the first premixing vessel is 65℃~75℃, the pressure is 0.1MPaG, and the stirring speed is 40rpm~50rpm. When using low-cis polybutadiene rubber polymer solution as raw material, the temperature of the second premixing vessel is 100℃~110℃, the pressure is 0.5MPaG, and the stirring speed is 50rpm~60rpm; when using solution-polymerized styrene-butadiene rubber polymer solution as raw material, the temperature of the second premixing vessel is 110℃~120℃.

4. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The premixing unit includes a multi-stage polymerizer, which comprises at least two reactors connected in series, with a temperature gradient controlled at 110°C to 160°C.

5. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, When using low-cis polybutadiene rubber liquid as raw material, the operating temperature of the devolatilization tower is 120℃~130℃, and the pressure is 0.5MPaG; and / or When solution-polymerized styrene-butadiene rubber solution is used as raw material, the operating temperature of the devolatilization tower is 160°C and the pressure is 0.4 MPaG.

6. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The azeotropic distillation column is equipped with a solvothermal circulation loop, which is used to preheat the distillation feed with the waste heat from the polymerization reaction.

7. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The synthesis parameters of the rubber compound include: When preparing low-cis polybutadiene rubber compound, the catalyst used is n-butyllithium at a concentration of 1.5 mol / L to 2.0 mol / L, a dosage of 0.5‰ to 1.0‰, a polymerization temperature of 70℃ to 85℃, a pressure of 0.6 MPaG, and a reaction time of 4 h to 5 h; and / or When preparing solution-polymerized styrene-butadiene rubber (SBR) solution, the catalyst used is n-butyllithium with a concentration of 1.5 mol / L to 2.0 mol / L and a dosage of 0.5‰ to 1.0‰. The synthesis temperature is 50℃ to 65℃, the pressure is 0.3 MPaG to 0.5 MPaG, and the reaction time is 4h to 6h.

8. The method for continuous polymerization of rubber solution to produce engineering plastics according to claim 1, characterized in that, The parameters of the polymerization reaction include: When using low-cis polybutadiene rubber compound as raw material, the low-cis polybutadiene rubber compound accounts for 25%~35% of the total mass of the compound, styrene accounts for 45%~55% of the total mass of the compound, acrylonitrile accounts for 10%~15% of the total mass of the compound, dispersant accounts for 1%~2% of the total mass of the compound, and initiator accounts for 0.05%~0.1% of the total mass of the compound; the dispersant is sorbitan oleate, and the initiator is di-tert-butyl peroxide; and / or When solution-polymerized styrene-butadiene rubber (SBR) is used as raw material, the SBR accounts for 30% to 40% of the total mass of the rubber, styrene accounts for 50% to 60% of the total mass of the rubber, acrylonitrile accounts for 10% to 15% of the total mass of the rubber, and chemical additives account for 0.2% to 0.5% of the total mass of the rubber; the chemical additives include initiators, chain transfer agents, and antioxidants.

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