Production device and production method of special polycarbonate

Abstract

The invention provides a production device and a production method of special polycarbonate, and relates to the technical field of polycarbonate. The production device comprises a reactant blending tank, an ester exchange reactor, a pre-polycondensation reactor and a polycondensation reactor which are sequentially communicated, the reactant blending tank is used for melting reaction materials, the ester exchange reactor is used for carrying out ester exchange reaction to obtain oligomer, the pre-polycondensation reactor is used for carrying out pre-polycondensation reaction on the oligomer to obtain prepolymer, and the polycondensation reactor is used for carrying out polycondensation reaction on the prepolymer. The polycondensation reactor is used for carrying out polycondensation reaction on the prepolymer to obtain a polycondensation product; wherein the ester exchange reactor comprises at least three reaction cavities and at least one stirring device, the three reaction cavities are sequentially communicated in the height direction of the ester exchange reactor, the stirring device comprises a first driving part and a first stirring part, the first driving part is in driving connection with the first stirring part, and the first stirring part comprises at least three stirring parts; the three stirring parts are respectively positioned in the three reaction cavities. The special polycarbonate produced by the production device is good in optical performance.

Description

Technical Field

[0001] The present application relates to the technical field of polycarbonate, and in particular to a production device and a production method of special polycarbonate. Background Art

[0002] Traditional polycarbonate (PC) is synthesized from bisphenol A and carbonic acid diesters. This method has certain limitations. Bisphenol A has estrogenic effects and may pose potential risks to human health. Many countries have explicitly banned the use of BPA in the production of food containers and related medical devices, which has greatly restricted the application of BPA-based PC in related fields.

[0003] Isosorbide is a chemical derived from renewable resources such as corncobs and other plant fibers. It can replace bisphenol A as a monomer in polycarbonate. Isosorbide's rigid and chiral structure gives isosorbide-based polycarbonates a stable chemical structure, a high glass transition temperature, excellent optical properties, and transparency. However, the low hydroxyl activity of isosorbide makes it more difficult to synthesize high-molecular-weight polycarbonates compared to bisphenol A. Furthermore, the rigid structure of isosorbide results in poor mechanical flexibility and processing properties of isosorbide-based polycarbonates, limiting their use in engineering applications.

[0004] The flexibility and processing properties of specialty polycarbonates (isosorbide-based polycarbonates) can be improved by catalyzing the reaction activity of isosorbide and introducing flexible monomers for copolymerization modification. However, how to continuously produce the above-mentioned specialty polycarbonates has become an urgent problem to be solved. Summary of the Invention

[0005] The present application provides a production device and a production method for special polycarbonate. The device can improve the utilization rate of reaction raw materials and realize the continuous production of special polycarbonate with high viscosity and high optical properties.

[0006] In order to achieve the above objectives, this application provides the following technical solutions:

[0007] A first aspect of the present application provides a production device for a special polycarbonate, the production device comprising a reactant preparation tank, an ester exchange reactor, a pre-polycondensation reactor, and a polycondensation reactor, which are sequentially connected, wherein the reactant preparation tank is used to melt the reaction materials, the ester exchange reactor is used to perform an ester exchange reaction to obtain oligomers, the pre-polycondensation reactor is used to perform a pre-polycondensation reaction on the oligomers to obtain prepolymers, and the polycondensation reactor is used to perform a polycondensation reaction on the prepolymer to obtain a polycondensation product;

[0008] In which, the ester exchange reactor includes at least three reaction chambers and at least one stirring device, the three reaction chambers are connected in sequence along the height direction of the ester exchange reactor, the stirring device includes a first driving member and a first stirring member, the first driving member drives the first stirring member, the first stirring member includes at least three stirring parts, and the three stirring parts are respectively located in the three reaction chambers.

[0009] In one possible implementation, the three reaction chambers are respectively a first chamber, a second chamber, and a third chamber, the feed end of the first chamber is connected to the reactant preparation tank, the feed end of the second chamber is connected to the discharge end of the first chamber, and the feed end of the third chamber is connected to the discharge end of the second chamber;

[0010] The transesterification reactor further includes a first control valve and a second control valve, wherein the first control valve is arranged between the discharge end of the first chamber and the feed end of the second chamber, and the second control valve is arranged between the discharge end of the second chamber and the feed end of the third chamber.

[0011] In one possible implementation, the pre-polycondensation reactor has a reaction cavity, and a plurality of guide plates are sequentially spaced in the reaction cavity along the height direction of the pre-polycondensation reactor. The guide plates are provided with guide holes for forming the oligomer film.

[0012] In one possible implementation, the polycondensation reactor includes a shell, a second driving member and a second stirring member, wherein the second driving member is drivingly connected to the second stirring member, the second driving member is fixed relative to the shell, and the second stirring member is located in the inner cavity of the shell;

[0013] The second stirring member includes a stirring shaft and an arc-shaped member sleeved on the stirring shaft. The stirring shaft is connected to the second driving member. The second driving member drives the stirring shaft to rotate and drives the arc-shaped member to rotate along the inner wall of the inner cavity of the condensation reactor.

[0014] In one possible implementation, two second stirring members are arranged at intervals in the inner cavity of the shell, and are both transmission-connected to the second driving member. The second driving member drives the stirring shaft to rotate, thereby driving the arc-shaped member to rotate against the inner wall of the inner cavity of the polycondensation reactor or the side wall of another stirring shaft.

[0015] In a possible implementation, the arc-shaped member includes a plurality of supporting spokes and an arc-shaped scraper. Along the circumference of the stirring shaft, the plurality of supporting spokes are fixed to the stirring shaft at intervals, and the arc-shaped scraper is connected to the supporting spokes.

[0016] In one possible implementation, the outer peripheries of the reactant preparation tank, the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor are all provided with heating jackets, which are configured to pass a heating medium to regulate the temperature inside the reactant preparation tank, the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor.

[0017] In one possible implementation, a vacuum device is further included, wherein the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor all have gas outlets, and the three gas outlets are all connected to the vacuum device, and the vacuum device is used to absorb the ester exchange steam, pre-polycondensation steam and polycondensation steam generated by the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor respectively, and to regulate the pressure inside the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor.

[0018] In one possible implementation, it further includes a reactant discharge pump, an oligomer discharge pump and a prepolymer discharge pump, wherein the reactant discharge pump is connected between the discharge end of the reactant preparation tank and the feed end of the ester exchange reactor, the oligomer discharge pump is connected between the discharge end of the ester exchange reactor and the feed end of the precondensation reactor, and the prepolymer discharge pump is connected between the discharge end of the precondensation reactor and the feed end of the condensation reactor.

[0019] The production device provided in the first aspect of the present application has at least the following beneficial effects:

[0020] The production device of special polycarbonate provided by the present invention includes a reactant mixing tank, an ester exchange reactor, a pre-polycondensation reactor and a polycondensation reactor that are connected in sequence. By continuously adding reaction raw materials, it is possible to achieve continuous production of special polycarbonate; due to the arrangement of multiple cavities from top to bottom in the ester exchange reactor, the reactants rely on gravity to flow in the reactor, and no additional power is required, which is conducive to the progress of the ester exchange reaction, improves the ester exchange rate, and thus improves the utilization rate of raw materials. Moreover, by providing a stirring device in the ester exchange reactor, the mixing effect of the materials in the reactor is improved, heat transfer is promoted, scaling and accumulation are prevented, reaction conditions are controlled, the reaction rate is increased, and product quality is improved, thereby ensuring the efficiency and stability of the ester exchange reaction process. In addition, the reactor design of the device makes the device occupy less space and has lower economic costs.

[0021] A second aspect of the present application provides a method for producing a special polycarbonate, which is performed using the production device described in any of the above technical solutions, and the production method comprises the following steps:

[0022] Passing the reaction raw materials into the reactant mixing tank and heating them to obtain a molten reactant, wherein the reaction pressure in the reactant mixing tank is 110-230 kPa and the temperature is 100-130° C.;

[0023] Passing the molten reactant into the transesterification reactor to react and obtain oligomers, wherein along the height direction of the transesterification reactor, the pressure in the three reaction chambers decreases from top to bottom, and the temperature in the three reaction chambers increases from top to bottom, and the pressure is 2-50 kPa and the temperature is 140-185° C.;

[0024] Passing the oligomer into the precondensation reactor to react and obtain a prepolymer, wherein the pressure in the precondensation reactor is 0.4-1.0 kPa and the temperature is 195-223° C.;

[0025] The prepolymer is introduced into the polycondensation reactor for reaction to obtain a polycondensation product, wherein the pressure in the polycondensation reactor is 0.050-0.25 kPa and the temperature is 235-255° C.

[0026] The production method provided in the second aspect of the present application has all the beneficial effects of the production device provided in the first aspect of the present application, which will not be repeated here. In addition, the production method of the special polycarbonate provided by the present invention, due to the use of the above-mentioned production method, not only has the advantage of high utilization rate of reaction raw materials, but also the special polycarbonate produced has the characteristics of high viscosity and high optical properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0028] Figure 1 This is a schematic structural diagram of the production device of special polycarbonate provided in the examples of this application.

[0029] Description of reference numerals:

[0030] 100. Reactant preparation tank; 200. Transesterification reactor; 210. Reaction chamber; 211. First chamber; 212. Second chamber; 213. Third chamber; 214. Partition; 220. Stirring device; 221. First driving member; 222. First stirring member; 230. First control valve; 240. Second control valve; 300. Pre-polycondensation reactor; 310. Guide plate; 311. Diversion hole; 400. Polycondensation reactor; 410. Shell; 420. Second driving member; 430. Second stirring member; 500. Heating jacket; 600. Vacuum device; 700. Reactant discharge pump; 800. Oligomer discharge pump; 900. Pre-polymer discharge pump; 910. Pelletizer.

[0031] The above drawings illustrate specific embodiments of the present application, which will be described in more detail below. These drawings and the textual description are not intended to limit the scope of the present application in any way, but rather to illustrate the concepts of the present application to those skilled in the art by reference to specific embodiments. DETAILED DESCRIPTION

[0032] As described in the background art, traditional polycarbonate is synthesized from bisphenol A and carbonic acid diesters. This method has certain limitations. Bisphenol A has an estrogenic effect and may cause potential harm to human health. Many countries have explicitly banned bisphenol A from being used to produce food containers and related medical devices, which has greatly limited the application of bisphenol A-type PC in related fields. Isosorbide is a chemical derived from renewable resources such as plant fibers such as corn cobs. It can replace bisphenol A as a monomer for polycarbonate. Isosorbide has a rigid and chiral structure, which makes isosorbide-based polycarbonate have a stable chemical structure, high glass transition temperature, excellent optical properties and transparency, etc. However, the hydroxyl activity of isosorbide is low, making it more difficult to synthesize high molecular weight polycarbonate compared to bisphenol A. In addition, the rigid structure of isosorbide causes the mechanical flexibility of isosorbide-based polycarbonate to be poor, and the processing performance is poor, which limits its engineering use.

[0033] The inventors have discovered that the flexibility and processing properties of specialty polycarbonates (isosorbide-based polycarbonates) can be improved by catalyzing the reactivity of isosorbide and introducing flexible monomers for copolymerization modification. However, how to continuously produce the above-mentioned specialty polycarbonates has become an urgent problem to be solved.

[0034] In response to the above technical problems, the embodiment of the present application provides a production device for special polycarbonate, which includes a reactant mixing tank, an ester exchange reactor, a pre-condensation reactor and a condensation reactor that are connected in sequence. By continuously adding reaction raw materials, it is possible to achieve continuous production of special polycarbonate; due to the arrangement of multiple cavities from top to bottom in the ester exchange reactor, the reactants rely on gravity to flow in the reactor, and no additional power is required, which is conducive to the progress of the ester exchange reaction, improves the ester exchange rate, and thus improves the utilization rate of raw materials. Moreover, by providing a stirring device in the ester exchange reactor, the mixing effect of the materials in the reactor is improved, heat transfer is promoted, scaling and accumulation are prevented, reaction conditions are controlled, the reaction rate is increased and the product quality is improved, thereby ensuring the efficiency and stability of the ester exchange reaction process. In addition, the reactor design of the present device makes the device occupy less space and has lower economic costs.

[0035] In order to make the above-mentioned purposes, features and advantages of the embodiments of the present application more obvious and easy to understand, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0036] Combine Figure 1 The production device of special polycarbonate provided in an embodiment of the present application includes a reactant preparation tank 100, an ester exchange reactor 200, a pre-polycondensation reactor 300 and a polycondensation reactor connected in sequence. The reactant preparation tank 100 is used to melt the reaction materials, the ester exchange reactor 200 is used to perform an ester exchange reaction to obtain oligomers, the pre-polycondensation reactor 300 is used to perform a pre-polycondensation reaction on the oligomers to obtain prepolymers, and the polycondensation reactor is used to perform a polycondensation reaction on the prepolymers to obtain polycondensation products; wherein, the ester exchange reactor 200 includes at least three reaction chambers 210 and at least one stirring device 220, and the three reaction chambers 210 are sequentially connected by pipelines along the height direction of the ester exchange reactor 200, and the stirring device 220 includes a first driving member 221 and a first stirring member 222, the first driving member 221 drives and connects to the first stirring member 222, and the first stirring member 222 includes at least three stirring parts, and the three stirring parts are respectively located in the three reaction chambers 210.

[0037] That is to say, three stirring parts are coaxially arranged in the ester exchange reactor 200. For example, the stirring parts are blades, and each chamber can be provided with blades of different structural forms according to the different viscosities of the liquid in the cavity. For example, the blades are propeller blades or anchor blades, which respectively serve as stirring processes for low-viscosity liquids and high-viscosity liquids.

[0038] In this way, by continuously adding reaction raw materials to the production device, it is possible to achieve continuous production of specialty polycarbonate; due to the arrangement of multiple cavities from top to bottom in the transesterification reactor 200, the reaction raw materials can flow in the transesterification reactor 200 in the form of a plug flow. The reactants flow in the reactor by gravity, without the need for additional power, which is conducive to the progress of the transesterification reaction, improves the transesterification rate, and thus improves the utilization rate of the raw materials. Moreover, by providing a stirring device 220 in the transesterification reactor 200, the mixing effect of the materials in the reactor is improved, heat transfer is promoted, scaling and accumulation are prevented, reaction conditions are controlled, the reaction rate is increased, and product quality is improved, thereby ensuring the efficiency and stability of the transesterification reaction process. In addition, the reactor design of this device makes the device occupy less space and has lower economic costs.

[0039] Illustratively, adjacent chambers of the ester exchange reactor 200 are separated by partitions 214, which can be arranged at equal intervals or unequal intervals, preferably at equal intervals; the inner wall of each chamber is provided with a material inlet and a material outlet, and the material outlet of each chamber is connected to the material inlet of the next chamber through a pipeline, and the pipeline is provided with a control valve to adjust the liquid level of each chamber.

[0040] Furthermore, the discharge ends of the reactant preparation tank 100, the ester exchange reactor 200, the pre-polycondensation reactor 300 and the polycondensation reactor are all liquid phase discharge ports. Preferably, the liquid phase discharge ports are all arranged at the bottom of each reactor to ensure the outflow of liquid phase materials.

[0041] It can be understood that the ester exchange reactor 200 is used to provide a place for ester exchange reaction. According to the actual production scale, additional ester exchange reactors 200 can be added. The present invention does not limit the number of added ester exchange reactors 200, wherein the added ester exchange reactor 200 includes at least two cavities.

[0042] In some embodiments, the three reaction chambers 210 are respectively a first chamber 211, a second chamber 212 and a third chamber 213, the feed end of the first chamber 211 is connected to the reactant preparation tank 100, the feed end of the second chamber 212 is connected to the discharge end of the first chamber 211, and the feed end of the third chamber 213 is connected to the discharge end of the second chamber 212; the ester exchange reactor 200 further includes a first control valve 230 and a second control valve 240, the first control valve 230 is arranged between the discharge end of the first chamber 211 and the feed end of the second chamber 212, and the second control valve 240 is arranged between the discharge end of the second chamber 212 and the feed end of the third chamber 213. Furthermore, the discharge end of the third chamber 213 is provided with a discharge pump controlled by a frequency converter, and a liquid level sensor is provided in each chamber. The liquid level sensor is respectively connected to the first and second control valves 240 signals, and the liquid level sensor is connected to the frequency converter discharge pump signal. In this way, the liquid level height in each chamber can be controlled by the cooperation of the liquid level sensor in each chamber, the first control valve 230, the second control valve 240 and the frequency converter discharge pump on the pipeline, thereby regulating the ester exchange reaction rate.

[0043] Furthermore, heating units are respectively provided in the first chamber 211, the second chamber 212 and the third chamber 213, so as to independently regulate the temperature in each chamber. In particular, the heating unit provided in the polycondensation reactor can provide optimal reaction conditions, thereby improving the degree of polymerization and purity of the final specialty polycarbonate product. By controlling the temperature and pressure of each cavity to be different, it is beneficial to fully carry out the ester exchange reaction.

[0044] In some embodiments, the pre-polycondensation reactor 300 has a reaction cavity, and along the height direction of the pre-polycondensation reactor 300, a plurality of guide plates 310 are sequentially spaced in the reaction cavity, and the guide plates 310 are provided with guide holes 311 for oligomer film formation. Exemplarily, the pre-polycondensation reactor 300 is a vertical falling film structure, and a multi-layer collector is also provided inside it. In this way, the multi-layer collector can increase the contact area of ​​the reactants, thereby improving the reaction efficiency. Through the multi-layer collector, the reactants can be more evenly distributed on the inner wall of the reactor during the flow process, promoting the progress of the polycondensation reaction, and the multi-layer collector helps to improve the mass transfer and heat transfer conditions inside the reactor. By increasing the surface area of ​​the liquid film, heat and material exchange can be carried out more effectively, ensuring that the reaction is carried out under optimal temperature and concentration conditions.

[0045] In some embodiments, the condensation reactor 400 includes a shell 410, a second driving member 420 and a second stirring member 430. The second driving member 420 drives the second stirring member 430, and the second driving member 420 is relatively fixed to the shell 410. The second stirring member 430 is located in the inner cavity of the shell 410; the second stirring member 430 includes a stirring shaft and an arc-shaped member sleeved on the stirring shaft. The stirring shaft is connected to the second driving member 420, and the second driving member 420 drives the stirring shaft to rotate, driving the arc-shaped member to rotate along the inner wall of the inner cavity of the condensation reactor 400.

[0046] It is understood that the pre-polycondensation reactor 300 and the polycondensation reactor 400 are used to provide a place for polycondensation. Depending on the actual production scale, the number of pre-polycondensation reactors 300 and polycondensation reactors 400 can be increased, and the present invention does not limit the number. Among them, the added polycondensation reactor is a devolatilization reactor.

[0047] In some embodiments, two second stirring members 430 are arranged at intervals in the inner cavity of the shell 410, and are both transmission-connected to the second driving member 420. The second driving member 420 drives the stirring shaft to rotate, thereby driving the arc-shaped member to rotate against the inner wall of the inner cavity of the condensation reactor 400 or the side wall of another stirring shaft.

[0048] In some embodiments, the arc-shaped member includes a plurality of supporting spokes and an arc-shaped scraper. Along the circumference of the stirring shaft, the plurality of supporting spokes are fixed to the stirring shaft at intervals, and the arc-shaped scraper is connected to the supporting spokes.

[0049] Exemplarily, the polycondensation reactor 400 is a double-shaft kneading reactor, and each stirring shaft is provided with a plurality of discs spaced apart along the axial direction, and each disc is connected to a scraper.

[0050] In some embodiments, the periphery of the reactant preparation tank 100, the ester exchange reactor 200, the pre-condensation reactor 300 and the condensation reactor 400 are all provided with a heating jacket 500, which is configured to pass a heating medium to regulate the temperature inside the reactant preparation tank 100, the ester exchange reactor 200, the pre-condensation reactor 300 and the condensation reactor 400.

[0051] In some embodiments, a vacuum device 600 is further included. The ester exchange reactor 200, the pre-condensation reactor 300 and the condensation reactor 400 all have gas outlets. Exemplarily, the gas outlets are located at the top of each reactor or the upper part of the inner chamber of the reactor to ensure the discharge of the reaction gas phase, and the three gas outlets are all connected to the vacuum device 600. The vacuum device 600 is used to absorb the ester exchange steam, pre-condensation steam and condensation steam generated by the ester exchange reactor 200, the pre-condensation reactor 300 and the condensation reactor 400 respectively, and to regulate the pressure inside the ester exchange reactor 200, the pre-condensation reactor 300 and the condensation reactor 400.

[0052] Illustratively, the vacuum device 600 includes a phenol condensation collection unit and a multi-stage vacuum pump. Since the ester exchange steam, pre-condensation steam and condensation steam contain a large amount of phenol vapor, the phenol condensation collection unit provided in the vacuum device 600 can realize the condensation, separation and recovery of the phenol vapor.

[0053] In some embodiments, a reactant discharge pump 700, an oligomer discharge pump 800 and a prepolymer discharge pump 900 are further included. The reactant discharge pump 700 is connected between the discharge end of the reactant preparation tank 100 and the feed end of the ester exchange reactor 200, the oligomer discharge pump 800 is connected between the discharge end of the ester exchange reactor 200 and the feed end of the precondensation reactor 300, and the prepolymer discharge pump 900 is connected between the discharge end of the precondensation reactor 300 and the feed end of the condensation reactor 400.

[0054] Furthermore, the production device also includes a cooling device, and the material outlet of the polycondensation reactor 400 is connected to the material inlet of the cooling device. Since the polycondensation product is in a molten state, the melt is cooled by the cooling device to obtain a cooled specialty polycarbonate.

[0055] In addition, according to actual production needs, a pelletizer and a slicer can also be set to pelletize and slice the product specialty polycarbonate to obtain the product specialty polycarbonate slices actually needed.

[0056] Furthermore, in order to further improve the purity of the product, the condensation product (special polycarbonate melt) discharged from the material outlet of the polycondensation reactor is passed through a melt discharge pump and filtered through a melt filter before entering a strand pelletizer, where it is pelletized under desalted water cooling conditions to obtain special polycarbonate chips.

[0057] On the other hand, an embodiment of the present application provides a method for producing a special polycarbonate, which is performed using the production device of any of the above embodiments of the claims, and the production method includes the following steps:

[0058] The reaction raw materials are introduced into the reactant preparation tank 100 and heated to obtain a molten reactant, wherein the reaction pressure in the reactant preparation tank 100 is 110-230 kPa and the temperature is 100-130°C. Exemplarily, the reaction pressure in the reactant preparation tank 100 is 110 kPa and the temperature is 100°C, or the reaction pressure in the reactant preparation tank 100 is 230 kPa and the temperature is 130°C.

[0059] The molten reactant is passed into the transesterification reactor 200 for reaction to obtain oligomers. Here, along the height direction of the transesterification reactor 200, the pressure in the three reaction chambers 210 decreases from top to bottom, and the temperature in the three reaction chambers 210 increases from top to bottom. The pressure is 2-50 kPa and the temperature is 140-185°C. The reaction raw materials enter the first chamber 211 from the material inlet of the transesterification reactor 200, are gradually mixed and reacted, and pass through the second and third chambers in the transesterification reactor 200 in sequence to fully react to generate transesterification steam and oligomers.

[0060] Optionally, the temperature ranges of the first chamber 211, the second chamber 212 and the third chamber 213 are 140-152°C, 156-169°C, and 175-185°C, respectively, and the pressure ranges are 30-50kPa, 15-25kPa, and 2-10kPa, respectively. For example, the temperature of the first chamber 211 is 140°C and the pressure is 30kPa, the temperature of the second chamber 212 is 169°C and the pressure is 25kPa, and the temperature of the third chamber 213 is 175°C and the pressure is 2kPa; or, the temperature of the first chamber 211 is 152°C and the pressure is 50kPa, the temperature of the second chamber 212 is 156°C and the pressure is 15kPa, and the temperature of the third chamber 213 is 185°C and the pressure is 10kPa.

[0061] The oligomer is introduced into the pre-polycondensation reactor 300 for reaction to obtain a prepolymer, wherein the pressure in the pre-polycondensation reactor 300 is 0.050-0.25 kPa and the temperature is 235-255° C. For example, the pressure and temperature in the pre-polycondensation reactor 300 are 0.050 kPa and 235° C., or the pressure and temperature in the pre-polycondensation reactor 300 are 0.25 kPa and 255° C.; the prepolymer is introduced into the polycondensation reactor for reaction to obtain a polycondensation product, i.e., the oligomer is output through the material outlet of the transesterification reactor 200 and is discharged through the oligomer discharge pump 800 via The material inlet of the pre-polycondensation reactor 300 enters the pre-polycondensation reactor 300; the pre-polycondensation reactor 300 is a vertical falling film structure, and the oligomer flows down in the polycondensation reactor in a film-like manner, and the viscosity continues to increase, generating prepolymer and pre-polycondensation steam. The prepolymer is output from the material outlet of the pre-polycondensation reactor 300, and then sent to the polycondensation reactor through the prepolymer discharge pump 900; the polycondensation reactor is a double-axis kneading structure, and the prepolymer continues to increase in viscosity in the polycondensation reactor to generate polycondensation products and polycondensation steam. The polycondensation products are discharged through the liquid phase outlet of the polycondensation reactor 400, and the polycondensation products are the product special polycarbonate.

[0062] In this way, the oligomer flows through the pre-condensation reactor 300 and the condensation reactor 400 in sequence. Through the two condensations, the polymerization degree of the condensation product can be gradually increased. Moreover, as the polymerization degree increases, the viscosity of the condensation product gradually increases. In this way, the molecular weight and viscosity of the condensation product can be effectively controlled, and it is also beneficial to remove impurities in the product, thereby improving the purity of the condensation product.

[0063] It should be noted that the reaction raw materials continuously enter from the material inlet of the reactant preparation tank 100, and after the reactants are melted, they are sent to the ester exchange reactor 200 through the reactant discharge pump 700, stay in the ester exchange reactor 200 for the preset reaction time, and then discharge from the material outlet of the ester exchange reactor 200, and then flow through the pre-condensation reactor 300 and the condensation reactor 400 in turn and stay for the preset reaction time, thereby realizing continuous reaction and achieving the purpose of continuous production; at the same time, the present invention can also effectively control the molecular weight and viscosity of special polycarbonate, thereby improving its purity.

[0064] Furthermore, the reaction raw materials include carbonic acid diester, isosorbide, 1,4-cyclohexanedimethanol, tetramethylammonium acetate and a lithium-based compound, wherein carbonic acid diester and isosorbide are main raw materials, 1,4-cyclohexanedimethanol is a third monomer, and tetramethylammonium acetate and a lithium-based compound are composite catalysts. Furthermore, the molar ratio of isosorbide to the molar ratio of 1,4-cyclohexanedimethanol is 1.5 to 4.0, for example, the molar ratio of isosorbide to the molar ratio of 1,4-cyclohexanedimethanol is 1.5 or 4, and the ratio of the molar number of carbonic acid diester to the sum of the molar numbers of isosorbide and 1,4-cyclohexanedimethanol is 1.01 to 1.23, for example, the ratio of the molar number of carbonic acid diester to the sum of the molar numbers of isosorbide and 1,4-cyclohexanedimethanol is 1.01 or 1.23. The lithium compound of the composite catalyst includes at least one of lithium chloride, lithium acetylacetonate, lithium lactate, and lithium hydroxide. The amount of tetramethylammonium acetate added to the composite catalyst is 80 to 230 ppm, for example, 80 ppm or 230 ppm. The amount of the lithium compound added is 130 to 300 ppm, for example, 300 ppm or 130 ppm. It should be noted that the above amounts are relative to the final specialty polycarbonate product.

[0065] Example 1

[0066] Reference Figure 1 The process uses diphenyl carbonate and isosorbide as the main raw materials, 1,4-cyclohexanedimethanol as the third monomer, and tetramethylammonium acetate and lithium chloride as a composite catalyst. The molar ratio of isosorbide to 1,4-cyclohexanedimethanol is 2.3, the molar ratio of the carbonate diester to the sum of the moles of isosorbide and 1,4-cyclohexanedimethanol is 1.03, the tetramethylammonium acetate addition amount is 120 ppm, and the lithium compound addition amount is 200 ppm. Diphenyl carbonate, isosorbide, 1,4-cyclohexanedimethanol, tetramethylammonium acetate, and lithium chloride are added to reactant preparation tank 1 and heated to a molten state. The reactant preparation tank temperature is 110°C, the pressure is 115 kPa, and the residence time is 40 minutes.

[0067] The melted reactants in the reactant preparation tank flow out from the material outlet at the bottom of the reactant preparation tank 1, pass through the reactant discharge pump and enter the first chamber of the ester exchange reactor through the material inlet of the first chamber of the ester exchange reactor, and then pass through the second and third chambers in sequence. The reactants undergo ester exchange reaction to obtain oligomers and ester exchange steam; the temperatures of the three chambers of the ester exchange reactor are 145°C, 158°C, and 171°C, respectively, and the pressures are 32kPa, 18kPa, and 8kPa, respectively, and the residence times are 40min, 60min, and 85min, respectively; the ester exchange steam generated in each chamber is connected to the vacuum device through the gas outlet of each chamber.

[0068] The oligomers finally produced in the ester exchange reactor flow out from the liquid phase outlet at the bottom of the last chamber, pass through the oligomer discharge pump, and then enter the precondensation reactor through the material inlet at the top of the precondensation reactor; the oligomer undergoes a condensation reaction in the precondensation reactor, the reaction temperature of the precondensation reactor is 201°C, the pressure is 0.8 kPa, and the residence time is 20 minutes; the precondensation steam generated by the precondensation is connected to the vacuum device through the gas phase outlet of the precondensation reactor 3.

[0069] The prepolymer generated in the pre-polycondensation reactor flows out from the liquid phase material outlet at the bottom of the pre-polycondensation reactor, passes through the prepolymer discharge pump and then enters the polycondensation reactor through the material inlet at one end of the polycondensation reactor. The prepolymer further undergoes polycondensation reaction in the polycondensation reactor, and the reaction material is sent from one end of the reactor to the material outlet at the other end, polycondensation steam and polycondensation products; the reaction temperature of the polycondensation reactor is 240°C, the pressure is 0.08Pa, and the residence time is 200min; the polycondensation steam generated by the polycondensation is connected to the vacuum device through the gas phase outlet of the polycondensation reactor 4;

[0070] The polycondensation product generated in the polycondensation reactor is fed into a strand pelletizer through a melt discharge pump, pelletized under demineralized water cooling, and then dried to obtain special polycarbonate chips.

[0071] Test example

[0072] The special polycarbonate obtained in Example 1 was subjected to viscosity test and light transmittance test respectively.

[0073] 1. Intrinsic viscosity test of special polycarbonate

[0074] Weigh 0.25g of polymer sample into a 50mL volumetric flask. Using dichloromethane as the solvent, add an appropriate amount of dichloromethane. Once the sample is completely dissolved, dilute to volume and shake well. Then, add a certain volume of solution to the Ubbelohde viscometer, set the water bath temperature to 20°C, and measure the sample three times, with the time error for each measurement not exceeding 0.5s. Take the average value for calculation. The intrinsic viscosity can be calculated using the following formula:

[0075]

[0076] Where C is the concentration of the polymer solution, η sp and η r are the specific viscosity and relative viscosity, respectively, which can be calculated using the following formula:

[0077]

[0078] η sp =η r -1

[0079] In the above formula, t and t0 are the time taken for the polymer solution and pure dichloromethane solvent to flow through the capillary of the Ubbelohde viscometer, respectively.

[0080] 2. Light transmittance test

[0081] The copolymerization product was prepared into a film with a thickness of approximately 0.25 mm by solution casting using dichloromethane as a solvent. The transmittance of the film was analyzed by measuring the transmittance spectrum in the range of 200 to 800 nm using a Perkin Elmer Lambda 950 UV-Vis spectrophotometer.

[0082] The special polycarbonate chips of Example 1 have an intrinsic viscosity of 0.71 dl / g and a visible light transmittance of 88%.

[0083] The above describes in detail the preferred embodiments of the present invention and their experimental verification. It should be understood that numerous modifications and variations based on the concepts of the present invention can be made by those skilled in the art without inventive effort. Therefore, any technical solution that can be derived by those skilled in the art based on the concepts of the present invention through logical analysis, reasoning, or limited experimentation based on the existing technology should be within the scope of protection defined by the claims.

[0084] The production device and production method of special polycarbonate provided by the present invention can not only realize the continuous production of special polycarbonate, but also obtain special polycarbonate with high viscosity and high optical properties.

[0085] In the description of this application, it should be understood that the terms "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on this application.

[0086] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of the technical features being referred to. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of such features. Throughout the description of this application, "plurality" means at least two, for example, two, three, etc., unless otherwise specifically defined.

[0087] In this application, unless otherwise specified or limited, the terms "installed," "connected," "connect," "fixed," etc. should be understood in a broad sense. For example, they can refer to fixed connection, detachable connection, or integration; mechanical connection or electrical connection; direct connection or indirect connection through an intermediate medium; internal communication between two elements or interaction between two elements, unless otherwise specified. Those skilled in the art will understand the specific meanings of the above terms in this application based on specific circumstances.

[0088] In this application, unless otherwise expressly specified or limited, when a first feature is "above" or "below" a second feature, it may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Furthermore, when a first feature is "above," "above," or "above" a second feature, it may mean that the first feature is directly above or diagonally above the second feature, or simply means that the first feature is at a higher level than the second feature. When a first feature is "below," "below," or "below" a second feature, it may mean that the first feature is directly below or diagonally below the second feature, or simply means that the first feature is at a lower level than the second feature.

[0089] The various embodiments or implementation methods in this specification are described in a progressive manner. Each embodiment focuses on the differences from other embodiments, and the same or similar parts between the various embodiments can be referenced to each other.

[0090] It should be noted that phrases such as "one embodiment," "an embodiment," "exemplary embodiments," and "some embodiments" in this specification may indicate embodiments that may include a particular feature, structure, or characteristic, but not every embodiment necessarily includes that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an embodiment, it is within the knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other embodiments, whether explicitly described or not.

[0091] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, rather than to limit them. Although the present application 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 or all of the technical features therein. These modifications or replacements do not deviate the essence of the corresponding technical solutions from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A production device for special polycarbonate, characterized in that: The production device comprises a reactant preparation tank, an ester exchange reactor, a pre-polycondensation reactor and a polycondensation reactor which are sequentially connected, wherein the reactant preparation tank is used to melt the reaction materials, the ester exchange reactor is used to perform an ester exchange reaction to obtain oligomers, the pre-polycondensation reactor is used to perform a pre-polycondensation reaction on the oligomers to obtain prepolymers, and the polycondensation reactor is used to perform a polycondensation reaction on the prepolymers to obtain polycondensation products; In which, the ester exchange reactor includes at least three reaction chambers and at least one stirring device, the three reaction chambers are connected in sequence along the height direction of the ester exchange reactor, the stirring device includes a first driving member and a first stirring member, the first driving member drives the first stirring member, the first stirring member includes at least three stirring parts, and the three stirring parts are respectively located in the three reaction chambers.

2. The production device according to claim 1, characterized in that The three reaction chambers are respectively a first chamber, a second chamber and a third chamber, the feed end of the first chamber is connected to the reactant mixing tank, the feed end of the second chamber is connected to the discharge end of the first chamber, and the feed end of the third chamber is connected to the discharge end of the second chamber; The transesterification reactor further includes a first control valve and a second control valve, wherein the first control valve is arranged between the discharge end of the first chamber and the feed end of the second chamber, and the second control valve is arranged between the discharge end of the second chamber and the feed end of the third chamber.

3. The production device according to claim 1 or 2, characterized in that: The pre-polycondensation reactor has a reaction cavity. Along the height direction of the pre-polycondensation reactor, a plurality of guide plates are sequentially arranged in the reaction cavity at intervals. The guide plates are provided with guide holes for forming the oligomer film.

4. The production device according to claim 1 or 2, characterized in that: The polycondensation reactor comprises a shell, a second driving member and a second stirring member, wherein the second driving member is drivingly connected to the second stirring member, the second driving member is fixed relative to the shell, and the second stirring member is located in the inner cavity of the shell; The second stirring member includes a stirring shaft and an arc-shaped member sleeved on the stirring shaft. The stirring shaft is connected to the second driving member. The second driving member drives the stirring shaft to rotate and drives the arc-shaped member to rotate along the inner wall of the inner cavity of the condensation reactor.

5. The production device according to claim 4, characterized in that The two second stirring members are arranged at intervals in the inner cavity of the shell and are both connected to the second driving member. The second driving member drives the stirring shaft to rotate, thereby driving the arc-shaped member to rotate along the inner wall of the inner cavity of the condensation reactor or the side wall of another stirring shaft.

6. The production device according to claim 5, characterized in that The arc-shaped member includes a plurality of supporting spokes and an arc-shaped scraper. Along the circumference of the stirring shaft, the plurality of supporting spokes are fixed to the stirring shaft at intervals, and the arc-shaped scraper is connected to the supporting spokes.

7. The production device according to claim 1 or 2, characterized in that: The outer peripheries of the reactant preparation tank, the ester exchange reactor, the pre-condensation reactor and the polycondensation reactor are all provided with heating jackets, which are configured to pass a heating medium to regulate the temperature inside the reactant preparation tank, the ester exchange reactor, the pre-condensation reactor and the polycondensation reactor.

8. The production device according to claim 1 or 2, characterized in that: It also includes a vacuum device, the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor all have air outlets, and the three air outlets are all connected to the vacuum device, and the vacuum device is used to absorb the ester exchange steam, pre-polycondensation steam and polycondensation steam generated by the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor respectively, and to regulate the pressure inside the ester exchange reactor, the pre-polycondensation reactor and the polycondensation reactor.

9. The production device according to claim 1 or 2, characterized in that: It also includes a reactant discharge pump, an oligomer discharge pump and a prepolymer discharge pump. The reactant discharge pump is connected between the discharge end of the reactant preparation tank and the feed end of the ester exchange reactor, the oligomer discharge pump is connected between the discharge end of the ester exchange reactor and the feed end of the precondensation reactor, and the prepolymer discharge pump is connected between the discharge end of the precondensation reactor and the feed end of the condensation reactor.

10. A method for producing a special polycarbonate, characterized in that: The production method is performed using the production device according to any one of claims 1 to 9, and comprises the following steps: Passing the reaction raw materials into the reactant mixing tank and heating them to obtain a molten reactant, wherein the reaction pressure in the reactant mixing tank is 110-230 kPa and the temperature is 100-130° C.; Passing the molten reactant into the transesterification reactor to react and obtain oligomers, wherein along the height direction of the transesterification reactor, the pressure in the three reaction chambers decreases from top to bottom, and the temperature in the three reaction chambers increases from top to bottom, and the pressure is 2-50 kPa and the temperature is 140-185° C.; Passing the oligomer into the precondensation reactor to react and obtain a prepolymer, wherein the pressure in the precondensation reactor is 0.4-1.0 kPa and the temperature is 195-223° C.; The prepolymer is introduced into the polycondensation reactor for reaction to obtain a polycondensation product, wherein the pressure in the polycondensation reactor is 0.050-0.25 kPa and the temperature is 235-255° C.

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