Compact plug flow type prepolymerization device for converting batch polymerization process into continuous polymerization process

Abstract

The invention relates to a plug flow type prepolymerization device, and aims to realize transition or conversion from a batch polymerization process to a continuous polymerization process. The device comprises a specially designed compact reactor body, wherein heat transfer elements are integrated on the wall surface and a shaft of the reactor body; the special stirring system is provided with a wall type stirrer and a central stirrer which can be independently operated; the plurality of feed ports are used for accurately controlling and uniformly dispersing an initiator, a monomer, a solvent and an additive; and an optimized temperature distribution system. This design minimizes the formation of gels and color while ensuring controllable reaction kinetics. The device can promote the production of a polymer with controllable molecular weight distribution, synthesizes a functionalized polymer precursor when a specific functional agent is added, and is used for the production of a special high-performance polymer, so that the flexibility of the process is improved, the consistency is improved, and the cycle time is shortened.

Description

TECHNICAL FIELD

[0001] The present invention can be classified according to the following International Patent Classification (see the International Patent Classification - IPC):

[0002] • Chemical engineering - B01 J

[0003] • Macromolecular polymer chemistry - C08 F. BACKGROUND

[0004] The prior art has provided reactors and processes for both continuous and batch polymerization systems, including different designs of plug flow reactors (PFR) for a variety of polymerization systems. However, the prior art has failed to teach or suggest a compact device or system that can: (a) convert batch reactors into continuous reactors and interchangeably accommodate the polymerization of conjugated diene monomers (e.g., butadiene or isoprene) and aromatic vinyl monomers (e.g., styrene); (b) facilitate the industrialization or scale-up of a variety of functional polymer production methods reported in the literature; (c) facilitate the industrialization of laboratory scale methods to obtain complex, controllable structures, such as asymmetric block structures; (d) improve the operation of continuous processes to obtain more stable and reliable operation, narrower molecular weight distribution, shorter polymerization cycle, and less color.

[0005] The prior art describes how to make different types of polymers with the same monomer system, including anionic polymerization. In anionic polymerization, at least one end of the growing polymer is "living", providing a site for the addition of other monomers. The specific structure of the polymer depends on its method of polymerization.

[0006] With batch processes, highly structured polymers with very narrow molecular weight distribution and controlled composition can be obtained, such as tapered copolymers, where the co-monomer participates in the reaction simultaneously; block structures, such as block copolymers (di-block, tri-block, multi-block), can also be obtained by sequential addition of different monomers. Radial, branched, or multi-arm structures can be obtained using coupling agents, and these polymers are typically symmetric.

[0007] With continuous processes, copolymers with very wide molecular weight distribution and very wide composition distribution can be obtained, by continuously adding monomers that enter the reactor simultaneously at a controlled rate.

[0008] Recent technologies in the field of industrial rubber, elastomer and polymer production indicate that industrial scale production line designs can produce polymers through batch or continuous polymerization processes. However, the important challenge of how to economically and simply achieve a quick switch between batch and continuous processes (and vice versa) has not been effectively addressed. The goal is to increase operational flexibility, improve product quality (reduce gel index and yellowness index), expand product range (special structure types), and facilitate the synthesis of custom polymers with different structures to meet more special application needs.

[0009] In order to achieve the main objectives of the present invention, the specific technical challenges faced in the field in developing a solution include:

[0010] 1) Achieve a quick switch from batch to continuous process with a convenient and compact design. The prior art has failed to address the challenge of switching from a batch polymerization mode to a continuous polymerization mode using a suitable, simple and compact device.

[0011] 2) Control the reaction kinetics to eliminate side reactions and reduce gel and color. The prior art has failed to address the challenge of reducing gel formation during the polymerization process, especially in the case of polybutadiene rubber polymerization. The prior art has also failed to address the challenge of controlling and reducing the appearance of color or yellowness index or its change over time (for example during transportation, storage and use). This is related to the frequent occurrence of material accumulations in the stagnant zones (usually on the reactor walls) in the first polymerization reactor in continuous polymerization processes, which can lead to poor heat transfer and the production of gel and color.

[0012] 3) Produce special types of polymers, such as asymmetric block polymers for special applications. The prior art has failed to provide a simple, suitable solution to the challenge of industrializing the production of polymers with special structures (such as asymmetric block polymers dedicated to adhesive applications). Such polymers can be achieved by introducing high vinyl polymer chains or branches through coupling.

[0013] 4) Achieve a narrower molecular weight distribution in continuous processes. The prior art has failed to address the challenge of controlling the molecular weight distribution in continuous processes, thus failing to obtain products with a narrower, more consistent and more uniform distribution.

[0014] 5) Reduce residence time without affecting product quality. The prior art has failed to address the challenge of how to reduce residence time without affecting product quality or performance in order to reduce costs.

[0015] 6) Facilitate the synthesis of functional copolymers. The prior art has failed to address the challenge of how to facilitate the functionalization of styrene-butadiene copolymers at the chain end or along the chain using a compact, suitable device, thus obtaining functional polymers with highly dispersed silica for high performance tire applications.

[0016] Therefore, the present invention proposes a compact prepolymerization device to cope with these challenges and provide advantages such as increased flexibility of process operation, improved color and gel phenomena, wider product range, controllable molecular weight distribution, shorter residence time, and facilitated functionalization processes. SUMMARY

[0017] The main objective of the present invention is to design a tubular, dynamic, compact plug flow prepolymerization device or reactor that can convert batch processes into continuous processes. The device is designed for the polymerization of conjugated diene monomers (e.g., butadiene or isoprene) and aromatic vinyl monomers (e.g., styrene), but is also applicable to other solution polymerization systems. The device aims to achieve several objectives: (a) interconversion of batch and continuous processes; (b) synthesis of functionalized polymer precursors with functional components; (c) obtaining compositions with controllable structures (e.g., asymmetric block structures); (d) obtaining uniform polymers with narrower molecular weight distribution and shorter overall cycle times; and (e) avoiding side reactions, gel formation, and chromophore generation. The device is provided with multiple feed ports to enable uniform dispersion of initiators, monomers, solvents, and additives, and is equipped with a dedicated stirring system (containing different stirrers that can rotate in both directions at different speeds) and heat transfer elements (including shafts with cooling functions) for temperature control and self-cleaning. In summary, the present invention aims to increase the operational flexibility of industrial production facilities, product quality, and the variety of polymer structures.

[0018] The present invention provides a compact prepolymerization device or reactor with dynamic elements that operates in plug flow mode and can convert from batch to continuous processes. The device is designed for the polymerization of conjugated diene monomers (e.g., butadiene or isoprene) and aromatic vinyl monomers (e.g., styrene), but can also be used for other types of solution polymerization systems. In addition, the device can be used in continuous processes, thereby better controlling the molecular weight, reducing the polydispersity index, and shortening the overall polymerization cycle.

[0019] The main features of the prepolymerization device are: (a) the ability to flexibly convert a batch polymerization process into a continuous process, thereby increasing the variety of polymer structures that can be produced in an industrial facility; (b) the minimization of the presence of gels in the final product by reducing side reactions that can lead to chromophore component or chromophore formation; (c) the reduction of polymer residence time and thermal history, thereby reducing gels and color (Yellowness Index), and / or slowing the change in color over time during short, medium and long term storage, handling and use; (d) the ability to obtain special types of structures (asymmetric blocks) for the manufacture of differentiated polymers to be applied in adhesives and other high-end areas; (e) the ability to link high vinyl polymer chains by coupling for the attachment of bromides for flame retardant applications; (f) the ability to better control and obtain narrower molecular weight distributions when using a continuous process, thereby obtaining more homogeneous products.

[0020] Figure 1 A plug flow prepolymerization device is shown. It is a stirred pipe reactor comprising a jacketed pipe reactor with a specially designed stirring system that alternately stirs low and high viscosity polymer solutions, meeting the high demands of uniformity under extreme flow characteristics (design to handle viscosities up to 10 million mPa-s). The stirring system comprises: (a) independent high speed central axial stirrers distributed radially from the shaft for stirring the reaction mixture and assisting heat transfer; (b) an independent shaft for driving a low speed running mixing element consisting of a helical peripheral scraper with a flexible tip (preferably made of polytetrafluoroethylene) for scraping the pipe wall to achieve self-cleaning and eliminate polymer buildup and gel formation on the pipe wall.

[0021] The high and low speed running internal shafts and their respective mixing elements are arranged along the geometric axis of the equipment, with an extension length approximately the same as the reactor length, leaving enough polymerization space between the shell and the internal moving parts. The high speed running central axial flow mixing elements or stirrers provide high local power input, achieving high efficiency of dispersion, dissolution and surface movement, thereby shortening the mixing time and promoting heat transfer. The high speed running central axial stirrers that can be used are of the A200 or A310 type, which produce a continuous downward pumping action, then circulating to the top and returning to the stirrer area, with strong overall circulation capacity, improving the transfer of stirring energy and macro-mixing effect. The direction of transport of the high speed running central mixing elements is opposite to that of the helical mixing elements of the outer stirrers. The coaxially arranged low speed running helical mixing elements (or low speed running helical peripheral scrapers) are in close contact with the wall of the tubular shell of the prepolymerization device to provide homogenization and efficient heat transfer under high viscosity conditions, preventing gel formation due to the narrow gap at the container wall.

[0022] The shaft of the prepolymerization device can be equipped with cooling elements and must be fitted with a double-acting mechanical seal, which consists of two seals arranged in series between the drive shaft and the device housing. The inner seal (or "primary seal") serves to retain the material within the housing, while the outer seal (or "secondary seal") serves to prevent material leakage.

[0023] The prepolymerization device contains multiple inlets for the independent addition of monomer, solvent, catalyst solution, and other additives. The prepolymerization device also has an outlet for the delivery of the polymer solution to a conventional reactor.

[0024] The prepolymerization device allows for short mixing times, highly uniform polymer solutions, efficient heat transfer, and self-cleaning functionality, thereby preventing gel formation and color changes, which in turn shortens mixing or batch processing times, improves control precision, and results in a narrower molecular weight distribution. The polydispersity index of the polymer produced using the prepolymerization device is preferably less than 3, more preferably less than 2, and most preferably less than 1.5.

[0025] A pump and / or pressure feed system passes the reaction mixture through the prepolymerization device. To maintain the necessary plug flow within the device, the agitator is carefully designed to minimize the accumulation of reaction mixture on the agitator and shaft, and is equipped with a dedicated internal cooling system. The prepolymerization device is designed and simulated to ensure that its fluid dynamics are capable of preventing the formation of stagnant or slow-flow areas (i.e., dead zones), which are typically located at the wall or downstream surface of the agitator and can lead to poor heat transfer, device plugging, gel formation, and color generation.

[0026] The operation of the prepolymerization device includes the independent feeding of reaction mixture components, typically monomer and solvent. Additives, branching agents, functionalization agents, and initiators can also be fed independently through multiple inlets to improve dispersibility. The components are preferably delivered by a pumping mechanism, but pressure feeds (e.g., pressure vessels with control valves) can also be used to deliver the components. A variety of pumping devices can be used for the feed of the prepolymerization device, as long as their seals are capable of excluding oxygen, water, and other impurities that can deactivate the reactants. Suitable pumping devices include gear pumps, diaphragm pumps, centrifugal pumps, piston pumps, and peristaltic pumps.

[0027] The piping used to deliver the reaction mixture components to the prepolymerization device should be of a material that can withstand high pressure and deactivate the initiators used (e.g., water and oxygen), preferably 316L stainless steel. The rate at which the reaction mixture components are pumped into the reactor can be adjusted so that the residence time of the reaction mixture in the reactor (for a 10 to 20 liter device) is from about 5 minutes to about 60 minutes or less, preferably from about 20 to about 30 minutes. The feed rate and the concentration of the reaction mixture components can vary depending on the type of product, the type of prepolymerization device, and the degree of polymerization desired before entering the next continuous reactor. The prepolymerization device can be subjected to a neutralization or curing treatment prior to use in the process of the present application. A typical neutralization process is to fill the reactor with a dilute initiator solution and allow it to sit for about 24 hours. The neutralization mixture can then be removed using a gas purge and a suitable anhydrous solvent.

[0028] The purified reaction mixture components can be pumped into the reactor, and the initiator can also be pumped into the reactor. The reaction mixture components can optionally pass through a heat exchanger before entering the reactor. The use of a heat exchanger is optional when it is desired to control the operating temperature of the reactor to be higher or lower than the temperature of the reaction mixture components before they enter the reactor.

[0029] The temperature maintained in the prepolymerization device depends on the materials used and the type of reaction desired, but in general, the system is capable of operating between 20 °C and 120 °C, most preferably between 60 °C and 90 °C.

[0030] In addition to temperature control, one key feature of the prepolymerization device is the ability to flow the reaction mixture contained therein from the inlet end of the device to the outlet end in a near plug flow. Near plug flow means that the reaction mixture flows continuously with approximately the same velocity profile throughout the device. The reaction mixture can be transported by an external device, such as by pumping. A side mixing device of the stirring system can facilitate the formation of plug flow. The monomer concentration of the reaction mixture is preferably between 10 and 30 weight percent, more preferably between 15 and 25 weight percent. These concentrations make it easier for the reaction mixture to flow downstream during polymer formation.

[0031] The prepolymerization device can be used to synthesize a functionalized polymer or copolymer, or to polymerize a macromonomer or oligomer containing a "functional group" or reactive group. These functional groups can be unprotected or protected and capable of terminating the polymer chain. Different functionalized polymers produced in the prepolymerization reactor can be added to the non-functionalized or functionalized polymers or copolymers obtained in the standard polymerization reactor or reactor train, thereby obtaining a functionalized polymer with one or more functional groups distributed along the chain or at the chain end. For styrene-butadiene copolymers (SSBR), it is particularly effective and practical to functionalize the copolymer with the prepolymerization device by this mechanism.

[0032] The prepolymerization apparatus described herein can be used to make functionalized polymers or functionalized formulations having multiple sites of reactivity when applied to batch polymerization processes. These functionalized formulations can be introduced into the batch reaction of conjugated diene monomers (e.g., butadiene or isoprene) and aromatic vinyl monomers (e.g., styrene, a-methylstyrene) at an appropriate time in the polymerization stage to link two living polymer chains, impart functionality to the polymer, and increase the average molecular weight. As has been extensively described in the literature, terminal functionalized materials can be synthesized by the addition of formulations containing active halogen or unsaturation that are capable of quenching the "living" anion of the polymerization.

[0033] Anionic polymerization is not suitable for the polymerization of monomers containing relatively acidic proton donor groups (e.g., amino, hydroxyl, thiol, carboxyl, or acetylenic groups). These groups are protected after functionalization and can be easily removed in post-polymerization treatments. Suitable functionalization formulations include oxygen, water, hydrogen, water vapor, alcohols, ketones, esters, amines, hindered phenols, and the like, such as chlorosilanes, ClSiMe2NMe2, ClSiMe2OR, ClSiMe2H, 1,3-bis(trimethylsilyl)carbodiimide, 1-(3-bromopropyl)-2,2,5,5-tetramethyl-1-aza-2,5-disilacyclopentane, and other chemicals extensively reported in the literature.

[0034] Suitable multifunctional or multi-site quenchers include dimethyl phthalate, phosphorus trichloride, methyltrichlorosilane, silicon tetrachloride, hexachlorodisilane, 1,2,3-tris(chloromethyl)benzene, dichlorodimethylsilane, dibromo-p-xylene, cyclo-p-xylene, dichloromethyl ether, diiodomethane, 1,4-dibromo-2-butene, 4-diiodo-2-butene, 1,2-dibromoethane, and other quenchers extensively reported in the literature. The present invention relates to a process to more conveniently prepare and introduce these functionalization methods to obtain functionalized polymers.

[0035] Functional copolymers of conjugated dienes and aromatic vinyl monomers containing reactive hydroxyl and / or carboxyl groups can be prepared, for example, by organic solvent polymerization of isoprene and / or 1,3-butadiene, or copolymerization of styrene or a-methylstyrene with isoprene and / or 1,3-butadiene. Methods of introducing hydroxyl and / or carboxyl functionality include, for example, free radical grafting of one or more target functional groups to the polymer backbone; copolymerization of a polymerizable material containing one or more target functional groups; deprotection of a protected copolymer group; addition to a partially unsaturated backbone; and, for end-capped polymers, reaction of a living polymer chain with a molecule containing a target functional group. The apparatus disclosed herein is capable of introducing such formulations in a precisely controlled manner to effect the functionalization process.

[0036] "Batch process" means that all of the starting materials are added to the prepolymerization device at the beginning of the reaction and the polymer exits the device at the end of the reaction.

[0037] "Continuous process" means that the reactants enter the prepolymerization device at a controlled rate simultaneously and the polymer exits the same reactor continuously.

[0038] "Living anionic polymerization" means chain polymerization by anionic mechanism without chain termination or chain transfer. "Star-branched polymer" means a polymer composed of several linear chains, each chain being connected together at one end by a single branch or branching point.

[0039] "Coupling agent" means a multifunctional anionically polymerizable monomer or a multifunctional quencher or branching agent that is added to form a star-branched polymer or a multi-armed polymer structure.

[0040] "Block" means a portion of a polymer chain in which all adjacent monomer units are of the same monomer. For example, AAAAABBBBB is a diblock copolymer containing A monomer units and B monomer units, and AAAAABBBBBAAAAA is a triblock copolymer containing A monomer units and B monomer units.

[0041] "Segment" means a polymer block formed by the addition of a particular monomer or coupling agent or branching agent (i.e., middle block - BBBBB; end block - AAAA).

[0042] "Asymmetric block" means a coupled or star block copolymer containing at least two different molecular weight arms (e.g., polystyrene end blocks, typically a high molecular weight polystyrene end block and a low molecular weight polystyrene end block).

[0043] "Terminator" means a reactive group that is capable of terminating a polymer chain. It attaches to the polymerization end of a polymer chain. The terminator can be multifunctional, thus capable of terminating multiple chains, thereby forming a star macromolecule.

[0044] "Plug flow" means a three-dimensional flow regime of the reaction mixture in which all of the reaction mixture moves at the same velocity along the direction of flow, without backflow, eddies, and dead spots.

[0045] "Residence time" means the time theoretically required for the reaction mixture to completely pass through the reactor.

[0046] "Reaction zone" means the area in a reactor or reactor system where the majority of the reaction takes place.

[0047] "Temperature profile" refers to the change in temperature or temperature curve of the reaction mixture as it flows through the reactor over time (e.g., if the temperature is constant throughout the reactor, the slope of the temperature profile is zero. When the temperature is increasing throughout the reactor, the slope of the profile is positive).

[0048] "Reaction mixture" refers to a mixture comprising at least one of an anionically polymerizable monomer, an initiating system, and a solvent. The role of the initiating system is to generate an anion in the presence of the monomer. The role of the solvent system, in addition to acting as a partial heat sink, is to promote the flowability of the monomer, the initiating system, and the final polymer.

[0049] "Monomer" refers to an anionically polymerizable monomer, typically a monomer with an unsaturated carbon-carbon bond at the end, such as a conjugated diene monomer (e.g., butadiene or isoprene) and an aromatic vinyl monomer (e.g., styrene or a derivative thereof).

[0050] It is well known that for certain specific monomers, there are particularly effective initiators. Initiators that are compatible with representative monomer systems are well described in the literature.

[0051] "Solvent" refers to a hydrocarbon compound that is compatible with the monomer system, which compounds are known in the art (e.g., hexane, cyclohexane, pentane). One or more solvents can be used as the reaction solvent system. The amount of solvent used is preferably sufficient to dissolve the reaction components (including any additional monomers added downstream) and the resulting product. Preferably, the solids content of monomer in the solvent is 10-15% by weight.

[0052] "Terminator" refers to a polar species whose reactive site can terminate a polymerization reaction, which is well described in the literature.

[0053] "Anionic polymerization mechanism" refers to the strong exothermic and moisture / air sensitive reaction that occurs when an alkyl lithium formulation reacts with styrene to form a styryl anion. This anion then reacts with additional styrene monomer until all of the remaining monomer is consumed, resulting in "living" polystyrene chains. After the monomer is completely consumed, these "living" polystyrene chains react with subsequent styrene monomer at subsequent locations in the reactor cross-section to produce higher average molecular weight homopolymers, or can be subjected to subsequent processing. The "living" polystyrene chains can also serve as precursors to a variety of different polymer structures.

[0054] "Protected functional group" refers to a functional unit that is reactive after removal of a "protecting" group that prevents reaction at a particular site.

[0055] "Functional agent" refers to a reactive moiety that contains a protected functional group that is capable of terminating or quenching an anionic polymer chain (resulting from anionic polymerization) and attaching to the end of the chain. BRIEF DESCRIPTION OF DRAWINGS

[0056] Figure 1 A precision plug flow prepolymerization device or reactor is presented, designed for the production and control of polymers using diene monomers and aromatic vinyl monomers. The device features a compact shell, placed vertically for ease of operation. It is equipped with heat transfer elements such as cooled shafts to maintain optimal reaction kinetics temperatures, prevent the occurrence of high temperature zones, reduce side reactions, avoid gelation, and improve polymer color and other indicators.

[0057] The core component of the device is the central drive motor (1), which drives the high-speed operating central axial stirrers (5), which are adapted to operate at high speeds to ensure efficient dispersion and heat transfer. The radial drive motor (2) operates independently, controlling the low-speed operating helical peripheral wipers (6), which mix the material at a lower speed and clean the reactor walls to prevent polymer accumulation.

[0058] The reactor head (3) integrates multiple ports, a temperature gauge (11), a vent (12), and a pressure gauge (13). The product fluid outlet (10) allows the discharge of the polymerization product to a conventional reactor for subsequent polymerization reactions.

[0059] The reactor body is provided with multiple ports (9), including independent feedstock inlets for the addition of chemicals, additives, initiators, solvents, and monomers, which are carefully positioned; in addition, there are sensor ports (11). The device is equipped with high-efficiency heat transfer elements for efficient cooling, including cooled shafts (4), cooling reactor coils, and jackets. The heat exchange fluid inlet and outlet (7) further constitute heat transfer elements, contributing to the temperature control of the device. This precise temperature control, combined with the jacketed channels (8) suitable for the application of heat exchange fluids, allows for fine-tuning of the reaction environment. Other elements are also crucial to the device's functionality: multiple sensor ports for real-time monitoring of process parameters, and a waste outlet for the discharge of waste or excess material.

[0060] This prepolymerization device is suitable for both batch and continuous polymerization processes, allowing for quick mode switching without extensive reconfiguration. It supports solution polymerization systems and enables the production of polymers with narrower molecular weight distributions.

[0061] The device is designed with a compact structure, and the continuous prepolymerization device has multiple carefully arranged inlets, a dedicated stirring system, and a high-efficiency heat transfer system, which helps to synthesize polymers in a continuous mode, converting batch processes into continuous processes, resulting in polymers with controllable structures and functional polymers suitable for high-performance applications such as technical compounds, flexographic printing, compatibilization processes, blends and alloys, asphalt modification (pavement and roofing applications), adhesives (hot melt, solvent-based pressure sensitive), and tires. DETAILED DESCRIPTION

[0062] The solution presented in this invention improves existing methods or results in several ways. First, it enables the use of both batch and continuous processes, providing greater operational flexibility. Second, it reduces undesirable side reactions such as gel formation and color generation, improving product quality. Third, it enables the production of special types of polymers, including asymmetric block polymers and functionalized polymers, to meet specific application requirements. Fourth, it better controls the molecular weight distribution in continuous processes, resulting in more stable and uniform products. Finally, it optimizes residence time without compromising product quality, reducing the operating costs of continuous processes. The design of the prepolymerization device aims to address these challenges and provide significant advantages in the field of styrene-diene polymerization.

[0063] Styrene-diene anionic polymerization processes have been widely described in the patent literature. This invention provides a new method for converting batch polymerization reactors for styrene-diene solution polymerization into a continuous process. The prepolymerization device described here is installed at the inlet of the batch reactor, converting it into a continuous reactor. Multiple batch reactors can be connected or interconnected according to conventional methods, forming a chain of continuous polymerization reactors.

[0064] The application of the prepolymerization device to batch reactors allows continuous operation without major modifications to the reactor chain structure. This prepolymerization device can be integrated into the feed system of existing batch reactors, allowing continuous addition of monomers, initiators, and key additives for polymerization. By precisely controlling feed flow rates and stirring parameters, this prepolymerization device ensures seamless conversion from batch to continuous operation, obtaining differentiated polymer structures, and thus improving process efficiency and productivity.

[0065] In this configuration, the prepolymerization device improves the uniformity of the polymer product, reduces residence time, and enables precise control of temperature and process parameters. In addition, its self-cleaning function and gel formation prevention mechanism enhance the reliability and stability of the process.

[0066] In addition, the versatility of the prepolymerization device allows it to adapt to existing continuous polymerization reactor chains, for use in the operation of polymerization reactor chains, thus better controlling the process and reducing residence time, ultimately improving product quality.

[0067] Advantages of the proposed innovative solution

[0068] A plug flow prepolymerization device is provided:

[0069] 1. It enables a quick switch from batch to continuous processing, with a compact structure.

[0070] 2. By controlling the reaction kinetics, eliminating side reactions, controlling the viscosity of the reaction mixture and the solubility of the polymer, the formation of gel and the development of color (yellowing) during polymerization is reduced.

[0071] 3. Side reactions are avoided, the formation of chromophores is prevented, and the development or change of color or yellowing index is controlled and reduced.

[0072] 4. Special types of different polymers can be produced in an industrial scale, including asymmetric blocks and other structures for special applications.

[0073] 5. The molecular weight distribution is controlled when using a continuous process, to obtain a narrower molecular weight distribution, resulting in a more consistent and homogeneous product.

[0074] 6. The residence time is reduced without affecting the quality or performance of the product, to reduce the cost of the continuous process.

[0075] The pre-polymerization device is compact in structure, and has the advantage that it can convert a batch process to a continuous process, and can be switched between the two process types, thereby providing greater operational flexibility for the process to obtain a wider range of products with different structures.

[0076] The pre-polymerization device is designed to be flexible in switching from a batch polymerization mode to a continuous polymerization mode, thereby improving the flexibility of the industrial process, expanding the product range (to obtain polymers with narrower and wider molecular and component distributions), improving product quality (to reduce the development and change of gel and yellowing index), and facilitating the synthesis of specially customized polymers. Using the pre-polymerization device, it is possible to flexibly switch from continuous process operation to batch process operation, while taking into account the solvent cleaning strategy and the optimal production sequence.

[0077] The pre-polymerization device is designed to optimally control the temperature in each region of the reactor, thereby positively affecting: (a) reaction kinetics control; (b) solution viscosity variation; (c) solubility of different reactants and additives. Using the pre-polymerization device, appropriate mixing and temperature control can be achieved at the beginning of the polymerization reaction, thereby obtaining the same polymer composition and structure as when the pre-polymerization reactor is not used, as well as similar average molecular weight and narrower polydispersity index.

[0078] The pre-polymerization device is designed to avoid the occurrence of side reactions that generate gel and color. These side reactions generate insoluble microgels and other chromophores, which can cause an increase in the rubber yellowing index in the short, medium and long term, even with the correct use of antioxidants and other stabilizers. This problem is particularly evident in polymers produced weeks or months after production (during transportation, storage and use), especially in rubbers or polymers with high polybutadiene content, and is not necessarily related to the poorer stability of the additives.

[0079] The pre-polymerization device is advantageous in that it enables the industrial production of different types of specialty polymers, including asymmetric block structures, which have proven to be very effective when formulated into pressure sensitive adhesives. When formulated into pressure sensitive adhesives with selected tackifiers, high molecular weight styrene blocks can provide the necessary physical cross-linking network, while low molecular weight S blocks impart good deformation capability and higher peel resistance to the system.

[0080] The pre-polymerization device is advantageous in that it enables the production of a more controlled, stable, and narrow molecular weight distribution or polydispersity index of the final polymer product. The average molecular weight of the resulting polymer is set by controlling the ratio of monomer to initiator. This ratio is achieved by controlling the flow rates of each monomer and initiator. The continuous polymerization process itself produces a broad molecular weight distribution. With the pre-polymerization device, a narrower molecular weight distribution can be achieved by better control of the temperature of the reaction mixture at the beginning of the polymerization. The strong agitation, heat transfer, and measures to avoid high temperatures minimize undesirable side reactions that can lead to the production of polymer chains of different average molecular weights, thus avoiding a broadening of the molecular weight distribution or an increase in the polydispersity index.

[0081] The pre-polymerization device is advantageous in that it enables the reduction or optimization of the reaction residence time without affecting the quality or performance of the product, thus reducing the operating costs of the continuous process. This is made possible by the fine control of heat transfer and the amount of reactants, especially the initiator. The initiator can be rapidly and independently added to the reaction mixture through multiple feed inlets, thus eliminating the induction period and controlling the average molecular weight of the polymer.

[0082] The pre-polymerization device is advantageous in that it enables the synthesis of functionalized copolymers. The pre-polymerization reactor can generate a functionalized polymer or copolymer precursor, a polymeric macromonomer or oligomer, which contains a "functional agent" or reactive group with an unprotected or protected functional group capable of terminating the polymer chain. The functionalized polymer generated in the pre-polymerization reactor can be added to the polymer or copolymer obtained in a standard polymerization reactor, thus producing a polymer with chemical functional groups on the chain or at the chain end, especially suitable for styrene-butadiene copolymers (SSBR).

[0083] Uniqueness

[0084] The innovation of the technical solution described in the present application is that a compact plug flow pre-polymerization device is designed. The device can flexibly convert batch process into continuous process. It is designed for the polymerization of conjugated diene monomers and aromatic vinyl monomers, but also applicable to other solution polymerization systems. The device has unique heat transfer elements, a dedicated stirring system equipped with independently operated wall and center stirrers, and multiple feed inlets, which can achieve fine control and uniform dispersion of initiators, monomers, solvents and additives. The advantages of the device include: higher operational flexibility, precise control of reaction kinetics, less side reactions and gel formation, better color control, production of special structure polymers, narrower molecular weight distribution, and optimized residence time, thereby reducing the cost of continuous polymerization process.

[0085] REFERENCES

[0086] 1. Mixing Efficiency Ekato Paravisc Impeller. Ch. Eng. Sc. 61. 2609-2617 (2006)

[0087] 2. H. L. Hsieh, R. P. Quirk, Anionic Polymerization: Principles and Applications, Marcel Dekker, New York (1996)

[0088] 3. J. J. Ma et al. Asymmetric Block Copolymers: Anionic Synthesis, Characterization. ACS Symp. Ser. Am. Chem. Soc. (1998)

[0089] 4. GB1496359A. Butadiene-styrene co-polymerization process and co-polymer produced thereby (1977). FIRESTONE

[0090] 5. JP4669186B2. Continuous manufacturing method of materials with controlled structure

[0091] 6. US11291973B2. Reactor and method for continuous polymerization. (2022). ARLANXEO

[0092] 7. CN101331152A. Horizontal boiling plug flow reactor (2008). FINA)

[0093] 8. US8066954B2. Plugflow reactor and polymers prepared therewith. (2011). FINA

[0094] 9. US20100331488A1. Tubular flow reactor and method for producing resin particle using the same. (2010). KONICA MINOLTA

[0095] 10. US4460278A. Continuous bulk polymerization reactor (1984). MITSUI

[0096] 11. EP2465604A1. Batch reactor and method for carrying out a polymerization reaction (2012). STAMICARBON-MT INNOVATION

[0097] 12. US9068031 B2. Reactor and method for continuous polymerization. (2015). ARLANXEO)

[0098] 13. EP0884360 A1. Technique for reducing the cold flow of rubbers. (1998). GOODYEAR)

[0099] 14. GB795182 A. Improvements in or relating to process for the polymerization of unsaturated hydrocarbons. (1958). HERCULES)

[0100] 15. AU1968043836 A1. Continuous process for the production of olefin polymers by polymerization of olefin monomers in organic solvent and for recovering and recycling solvent. (1970). NAT DISTILLERS & CHEM CORP)

[0101] 16. GB848064 A. Polymerization process and product. (1960). PHILLIPS)

[0102] 17. US3294766 A. Polymerization process. (1966). POLYMER)

[0103] 18. AU1986057098A1. Improved process for the polymerization or copolymerization of butadiene. (1986). ENICHEM)

[0104] 19. AU525740B. Incremental polymerisation of dienes. (1980). PHILLIPS)

[0105] 20. US3331821A. Catalyst composition and process of preparing conjugated diene polymers utilizing same. (1967). PHILLIPS)

[0106] 21. GB980093A. Improvements in or relating to a catalytic process for preparing polymeric oxetanes (1965). HERCULES)

[0107] 22. GB734501A. Improvements in or relating to ethylene and / or propylene polymerization. (1955). STANDARD OIL)

[0108] 23. GB894429A. Improvements in and relating to polymerization. (1962). DUPONT)

[0109] 24. EP0698623B1. Synthesis of trans-1,4-polybutadiene having controlled molecular weight. (1998). GOODYEAR

[0110] 25. EP0879833A1. Synthesis of trans-1,4-polybutadiene. (1998). GOODYEAR

[0111] 26. US3737419A. Alkene oxide polymerization. (1973). PHILLIPS

[0112] 27. US2825721A. Polymers and production thereof. (1958). PHILLIPS

[0113] 28. AU507329B. Preparation of rubber copolymers. (1979). PHILLIPS

[0114] 29. US3396125A. Alkene oxide polymerization. (1968). PHILLIPS

[0115] 30. US3383333A. Organometallic catalyst composition and use thereof in alkene oxide polymerization. (1968). PHILLIPS

[0116] 31. US3457197A. Polymerization of epihalohydrins alone or with oxirane compounds (1969). PHILLIPS

[0117] 32. US3562351A. Dimerization process. (1971). EXXON

[0118] 33. US2145501A. Production of aralkenyl compounds and polymerization products thereof. (1939). SHELL

[0119] 34. AU517290B. Impact resistant polystyrenes having improved transparency. (1979). DOW

[0120] 35. US3833659A. Preparation of oxygen-containing compounds. (1974). UOP

[0121] 36. US3657159A. Epoxide polymerization catalysts comprising complex organoaluminate compounds of silicon tin or phosphorus (1972). HERCULES

[0122] 37. GB847585A. Low pressure polymerization catalyst. (1960). EXXON

[0123] 38. EP3519500B1. Multi-modal polyisoolefin compositions and processes therefor (2023). ARLANXEO

[0124] 39. AU1964051474A1. Olefin polymerization catalyst (1964). CONTINENTAL

[0125] 40. GB794153A. Process for alkylating aromatic compounds (1958). UOP

[0126] 41. GB745343A. Recovery of pure phenol by distillation of reaction mixtures (1956). DISTILLERS

[0127] 42. GB832173A. Improvements in or relating to the production of o-divinylbenzene (1960). DU PONT

[0128] 43. US3639346A. Vinyl ketone polymerization (1972). PHILLIPS

[0129] 44. EP0700941B1. Process for preparing rubber-modified ABS moulding resin by non-aqueous polymerization process in the presence of solvants (1998). BAYER

[0130] 45. US3247270A. Cycloolefin production. (1966). COLUMBIAN)

[0131] 46. AU528721B. Process for the treatment of sugar solutions using ion exchange resins. (1980). ROHM & HAAS)

[0132] 47. US2143364A. Process for effecting catalytic reactions. (1939). SHELL)

[0133] 48. US20150252352A1. Magnetic hierarchical catalysts of nanoparticles and enzymes forming mesoporous assemblies embedded in macroporous scaffolds, and their use with magnetically-driven reactors and in chemical reactions. (2015). CORNELL UNIV.)

[0134] 49. GB755447A. Process for the production of polyesters from six-membered cyclic esters. (1956). JOHANNES KLEINE)

[0135] 50. US3586638A. Catalyst system comprising an organoaluminum or organozinc and a metal salt of a beta-diketone. (1971). PHILLIPS)

[0136] 51. US6140533A. Process for producing sec-butyl acrylate (2000). IDEMITSU

[0137] 52. AU1968038681A1. Method of producing polybutadiene. (1969). GOODYEAR

[0138] 53. GB319588A. Improvements in process of polymerizing vinyl derivatives. (1931). DU PONT

[0139] 54. AU1997028349A1. A process for manufacturing crystalline maltitol and crystalline mixture solid containing the same. (1998). MITSUBISHI

[0140] 55. AU279567B. Improvements in or relating to novel metal carbonyl catalysts and the uses thereof. (1964). PHILLIPS

[0141] 56. US1907317A. Process for producing hydration products from unsaturated hydrocarbons and water. (1933). BROWN RALPH

[0142] 57. US3278463A. Modified sulfonated cross-linked aryl catalytic resins. (1966). MONSANTO

[0143] 58. GB958161A. Polymerisation process. (1964). BPCHEM

[0144] 59. US4309515A. Translucent impact polymers. (1982). SHELL

[0145] 60. AU2013204389A1. Conjugates, particles, compositions, methods. (2013). CERULEAN

[0146] 61. AU546061B. Nucleated growth reactions. (1981). MOBIL OIL CORP

[0147] 62. US3715331A. Monomers soluble x-ray opaque methacrylate. (1973). COE LAB

[0148] 63. AU1988022062A1. Method of making 1-alkene / excess maleic anhydride polymers. (1989). SC JOHNSON

[0149] 64. US2499820A. Thiourea-hydrocarbon complexes. (1950)

[0150] 65. US2864790A. Certain polyepoxide treated amine-modified thermoplastic phenol-aldehyde resins and method of making same. (1958). GASOLINEITE)

[0151] 66. KR100416034B1. Method for preparing syndiotactic styrenic polymers by semi-dry powder polymerization (2004). SAMSUNG ATOFINA)

[0152] 67. BR112013022511A2. Polymer, composition, article and polymerization process thereof ARTIGO E PROCESSO PARA DE UM (2016). TRINSEO)

[0153] 68. IN5187DELNP2012A. Purification of isoprene from renewable resources. (2015). DANISCO | GOODYEAR)

[0154] 69. IN8558DELNP2010A. Polymacromonomer and process for production thereof. (2012). EXXONMOBIL)

[0155] 70. IN177746B. A hair care composition. (1997). PROCTER & GAMBLE)

[0156] 71. IN6637CHENP2015A. Processing biomass. (2016). XYLECO)

[0157] 72. DE1218159B. Process for the polymerization of 1,3 - butadiene (DE1218159B. Verfahren zur Polymerisation von 1,3 - Butadien (1966). PHILLIPS)

[0158] 73. DE826097A. Valve, especially for the compressed air lines of pneumatic tools (DE826097A. Ventil, insbesondere fuer Druckluftleitungen von Arbeitsgeraeten. (1951). PHILLIPS)

[0159] 74. IN6920DELNP2015A. Unsaturated polymer composition (IN6920DELNP2015A. “unsaturated polymer composition”. (2015). BOREALIS)

[0160] 75. IN202044021933A. Sioc - based polyethersiloxane (IN202044021933A. Sioc - based polyethersiloxane. (2020). EVONIK)

[0161] 76. JP4130268B2. Method for producing a rubber - modified styrene - based resin (JP4130268B2 ゴム変性スチレン系樹脂の製造法. (2008). DAICEL)

Claims

1. A compact prepolymerization device or reactor for fitting a batch or continuous polymerization reactor train for producing and controlling polymers from diene monomers and aromatic vinyl monomers, comprising: i. a compact tubular housing or compact tubular body characterized in that the reactor has a geometric center axis which is arranged substantially horizontally or substantially vertically during operation, the reactor is equipped with heat transfer elements comprising cooling shafts, ii. a dedicated stirring system with wall stirrers and central stirrers which can be operated independently, at variable speed, and in both directions, iii. a plurality of inlets configured for precise control and uniform dispersion of initiators, monomers, solvents, and additives, iv. an optimized temperature for precise control of reaction kinetics, thereby further reducing side reactions, minimizing gel formation, and improving color shade, v. a configuration capable of producing polymers with special structure and functionalization.

2. The apparatus of claim 1, wherein, The heat transfer elements further comprise a jacketed heat exchanger structure and a second heat exchanger system for the helical mixing elements for precise control of the temperature of the device, thereby further reducing side reactions, reducing gel levels, reducing color shade, and improving the quality and consistency of the polymer.

3. The apparatus of claim 1, wherein, Temperature control fluid is adapted to flow within the support structure of the helical mixing elements operating at slow speed.

4. The apparatus of claim 1, wherein, The slow running helical peripheral wiper of the stirring system acts as a coaxial mixing element with a flexible tip in close contact with the wall of the device, operating at a lower speed than the central stirrers, for mixing and self-cleaning to avoid polymer accumulation on the wall.

5. The apparatus of claim 1, wherein, The central stirrers comprise radial stirring elements adapted to operate at high speed to ensure efficient dispersion and heat transfer.

6. The apparatus of claim 1, wherein, The device has a plurality of inlets for feeding monomers, solvents, initiators, and dedicated ports for adding functional agents for chain end functionalization or along chain functionalization.

7. The apparatus of claim 1, wherein, The reactor has a length L to diameter D ratio (L / D) of 1 to 5 to 1 to 7.

8. The apparatus of claim 1, wherein, It is configured to quickly switch between batch and continuous polymerization modes without extensive reconfiguration.

9. The apparatus of claim 1, wherein, The tubular reactor body is configured to be adapted for batch or continuous production of polymers by solution polymerization of conjugated dienes and aromatic vinyl compounds or synthetic rubbers or elastomers, the device of claim 1, wherein the tubular reactor body is configured to be adapted to support solution polymerization systems other than conjugated diene monomers and aromatic vinyl monomers.

10. The apparatus of claim 1, wherein, The device is adapted to produce polymers with narrow molecular weight distribution and a polydispersity index less than 3.

11. The apparatus of claim 1, wherein, It is configured for the synthesis of polymer precursors with controlled structure including asymmetric block structure by coupling reactions.

12. The apparatus of claim 1, wherein, The plurality of inlets allows independent and simultaneous introduction of each component to adapt for precise control of process conditions, reaction kinetics, and molecular weight distribution.

13. The apparatus of claim 1, wherein, An outlet is also included for the delivery of the polymer solution to a conventional reactor for further polymerization processes.

14. A method for converting a batch polymerization process into a continuous polymerization process using the plug flow prepolymerization device of claim 1, comprising: i. adding a reaction mixture of monomers, solvent and initiator to the reactor, ii. starting the dedicated stirring system to ensure uniform mixing and temperature control, iii. independently adding functional agents through the plurality of inlets for directed functionalization, and iv. continuously outputting the polymerization product through the outlet for further processing.

15. The method of claim 14, wherein, Also included is controlling the cooling shaft to control the reaction temperature within a predetermined range.

16. The method of claim 14, wherein, The starting the dedicated stirring system includes setting the central stirrer to rotate in a direction opposite to the conveying direction of the helical mixing elements.

17. The method of claim 14, wherein, Also included is the step of adjusting the feed rates of the reaction mixture components to control the residence time.

18. The method of claim 14, wherein, The functional agents are added to synthesize functionalized polymers for high performance tire applications.

19. The method of claim 14, wherein, Also included is the use of pumps and / or pressure feed systems to drive the reaction mixture through the device.

20. A system for synthesizing functionalized polymers with controlled architecture, comprising: i. a plug flow pre-polymerization device as claimed in claim 1, ii. a feed system for delivering reaction mixture components to the device, and iii. a control system for adjusting parameters such as temperature, stirring speed and feed rates to produce polymers with desired molecular weight distribution and functionalization. iv. the use of macromonomers or polymer oligomers that include "functional agents" or reactive groups that include unprotected or protected functional groups that are capable of terminating polymer chains to enable attachment along the chain or at the chain end when added to a copolymer (i.e. styrene- butadiene copolymer) to provide multiple functionalization.

21. The system of claim 20, wherein, The feed system includes a gear pump, diaphragm pump, centrifugal pump, piston pump or peristaltic pump for delivering components of the reaction mixture.

22. The system of claim 20, wherein, Also included is a heat exchanger integrated with the feed system for preheating or cooling the reaction mixture components.

23. The system of claim 20, wherein, The control system is configured for remote operation and automation of the polymerization process.

24. The system of claim 20, wherein, Also included is a purification system for the reaction mixture components to remove impurities before introduction into the pre-polymerization device.

25. The system of claim 20, wherein, It is configured for producing asymmetric block copolymers for adhesive applications.

26. The system of claim 20, wherein, It is configured for producing branched coupled polymers with high ethylene content.

27. The system of claim 20, wherein, The control system includes sensors for monitoring polymerization process parameters in real time.

28. The apparatus of claim 1, wherein, The device can be used to synthesize polymer precursors from monomers, macromonomers or oligomers that include "functional agents" or reactive groups that include unprotected or protected functional groups that are capable of terminating polymer chains to enable attachment along the chain or at the chain end when added to a copolymer (i.e. styrene-butadiene copolymer) to provide multiple functionalization.

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