Continuous polymerization method of feve fluorocarbon resin and tubular and kettle mixing devices

Abstract

This invention discloses a continuous polymerization method for FEVE fluorocarbon resin and tubular and batch mixing apparatuses. The method includes the following steps: continuous feeding: reactants are continuously fed into the initial reactor according to the formula ratio to undergo prepolymerization reaction, followed by continuous polymerization to obtain the prepolymerized reaction material. The material level in the reactor is monitored and controlled to maintain within a set range; continuous polymerization: the prepolymerized reaction material enters the subsequent reactor to undergo postpolymerization reaction for continuous polymerization, yielding the FEVE fluorocarbon resin product; continuous discharge: the crude FEVE fluorocarbon resin product is collected at the outlet of the last reactor (generally the last tubular reactor, or the last batch mixing vessel). Compared with the prior art, this invention has advantages such as high automation, low energy consumption, good process stability, and strong product quality consistency.

Description

Technical Field

[0001] This invention relates to the field of polymerization technology, and in particular to a continuous polymerization method for FEVE fluorocarbon resin and tubular and batch mixing apparatus. Background Technology

[0002] FEVE fluorocarbon resin (FEVE-type fluorocarbon resin) is widely used in heavy-duty anti-corrosion engineering projects such as buildings and bridges, as well as functional materials such as solar backsheet films, due to its unique physicochemical properties, such as excellent heat resistance, chemical resistance, weather resistance, and electrical insulation. Currently, the industrial production of FEVE fluorocarbon resin mainly adopts the batch polymerization method, which has the following prominent problems: long polymerization reaction time and low production efficiency; low monomer conversion rate and high unit consumption; frequent heating and cooling to maintain a constant temperature inside the reactor during the reaction process, resulting in low energy efficiency and the risk of local thermal runaway; in addition, there are large fluctuations in product quality between batches, making it difficult to guarantee consistency. Therefore, facing the above technical bottlenecks, the industry urgently needs to develop a continuous polymerization production process that can achieve a high degree of automation, low energy consumption, good process stability, and strong product quality consistency. Summary of the Invention

[0003] To address the shortcomings of existing technologies, this invention designs a continuous polymerization method for FEVE fluorocarbon resin and a tubular and batch mixing device, including a continuous reaction device based on multiple reactors connected in series. This device, based on the traditional batch reaction, combines a reactor and a tubular reactor to achieve phased and continuous prepolymerization and post-polymerization of FEVE fluorocarbon resin in different reactors, thus completing the entire polymerization process. Furthermore, this process route combines the advantages of tubular reactors and reactors, offering high automation, low energy consumption, good process stability, and strong product quality consistency, while also providing high utilization of gaseous monomers and support for highly exothermic reactions. In addition, in traditional batch reactor reactions, to ensure complete reaction, fluorinated gaseous monomers often need to be added in excess to 105%~110% of the theoretical amount, which not only wastes raw materials and increases unit consumption but also increases the cost of subsequent separation and purification. This invention effectively solves these problems through continuous operation and process control.

[0004] To achieve the above objectives, the present invention provides the following technical solution: The first objective of this invention is to provide a continuous polymerization method for FEVE fluorocarbon resin, the method comprising the following steps: (1) Continuous feeding: The reaction raw materials are continuously fed into the initial reactor (generally one or more reaction vessels, or one or more tubular reactors) according to the formula ratio to carry out prepolymerization reaction, and continuous polymerization is carried out to obtain the reaction material after prepolymerization reaction. The material liquid level in the reaction vessel is monitored and controlled to be maintained within the set range. (2) Continuous polymerization: The reactants after the prepolymerization reaction enter the post-reactor (generally one or more tubular reactors, or one or more reaction vessels) to carry out the post-polymerization reaction for continuous polymerization, and obtain FEVE fluorocarbon resin products. (3) Continuous discharge: The crude FEVE fluorocarbon resin after polymerization is collected at the outlet of the last reactor (usually the last tubular reactor, or the last reaction vessel).

[0005] Furthermore, the initial reactor is one or more reaction vessels and / or one or more tubular reactors; the subsequent reactor is one or more reaction vessels and / or one or more tubular reactors.

[0006] Preferably, for all initial reactors and all subsequent reactors (i.e. all reactors), at least one reaction vessel and one tubular reactor are included.

[0007] Optionally, the method includes the following steps: (1) Continuous feeding: The reaction raw materials are continuously fed into one or more reactors according to the formula ratio to carry out prepolymerization reaction and continuous polymerization to obtain the reaction material after prepolymerization reaction. The material liquid level in the reactor is monitored and controlled to be maintained within the set range. (2) Continuous polymerization: The reactants after the prepolymerization reaction enter one or more tubular reactors, and the postpolymerization reaction occurs to carry out continuous polymerization to obtain FEVE fluorocarbon resin products. (3) Continuous discharge: The crude FEVE fluorocarbon resin after polymerization is collected at the outlet of the last tubular reactor.

[0008] Furthermore, the reaction raw materials include fluorine-containing gaseous monomers and hydrocarbon liquid monomers, initiators, additives, solvents, etc.

[0009] Furthermore, the inlet of the reactor or tubular reactor is connected to a feed pump and / or a pressure reducing valve and / or a regulating valve to control the feed rate of the reaction raw materials and maintain a constant feed rate.

[0010] Furthermore, the continuous feeding process controls the feed rate of the reaction raw materials through a feed pump or pressure reducing valve to keep the feed rate constant. The feed rate depends on the size of the reactor. The size of the reactor or tubular reactor and the feed rate determine the residence time of the material in each reactor or tubular reactor. No special requirements are made for the size of the reactor or tubular reactor and the feed rate, but in order to ensure the full progress of the polymerization reaction, the residence time of the material needs to be limited.

[0011] Furthermore, a discharge pump and / or a back pressure valve and / or a regulating valve are connected to the outlet of the last reactor to control the discharge rate of the FEVE fluorocarbon resin product and keep the discharge rate of the FEVE fluorocarbon resin product constant.

[0012] Furthermore, after the reactants have completed polymerization in the last post-reactor, the resulting FEVE fluorocarbon resin product is discharged stably and continuously through the discharge control system (such as a regulating valve, back pressure valve, or discharge pump), ultimately obtaining a product with a high monomer conversion rate.

[0013] Furthermore, the continuous discharge process controls the discharge rate of the crude FEVE fluorocarbon resin product through the discharge valve (which can be a back pressure valve or a regulating valve) or discharge pump of the reactor or tubular reactor, keeping the discharge rate of the FEVE fluorocarbon resin product constant and ensuring that the liquid level in all reactors is within a reasonable range. The sustainability of liquid level control determines the capacity of the continuous polymerization equipment.

[0014] Furthermore, the number of the reaction vessels is 1 to n, where 2 ≤ n ≤ 10.

[0015] Furthermore, the number of tubular reactors is 1 to n, where 2 ≤ n ≤ 10.

[0016] Furthermore, the prepolymerization reaction in the continuous polymerization process is carried out in the initial reactor and maintained at a certain temperature and pressure. If the reactor is a kettle, the liquid level also needs to be maintained. The pre-reacted material is continuously fed into the subsequent reactor at a constant rate to carry out the subsequent polymerization reaction.

[0017] Furthermore, the post-polymerization reaction in the continuous polymerization process takes place in a post-reactor and is maintained at a certain temperature and pressure.

[0018] Furthermore, the form, number, diameter, and length of the tubular reactors are mainly used to ensure the minimum flow rate, heat exchange efficiency, and required residence time of the material. Therefore, there are no specific requirements for the form, number, diameter, and length of the tubular reactors. The preferred number of tubular reactors is generally 2 to 30, with a diameter of φ5 to 200 mm and a length of 50 to 200 cm per reactor.

[0019] Furthermore, the mixing components within the tubular reactor primarily function to rapidly and uniformly mix the materials, achieving an effect equivalent to the stirring paddle in a traditional reactor. There are no specific limitations on the structure or style; generally, static support type, filling type, or dynamic stirring type are preferred. The tubular reactor is equipped with mixing components used to rapidly and uniformly mix the materials; these mixing components can be static support type, filling type, or dynamic stirring type.

[0020] Furthermore, multiple reactors (reaction vessels or tubular reactors) are connected in sequence, with the inlet of the first reactor connected to the outlet of the reactor, the inlet of the next reactor connected to the outlet of the previous reactor, and the outlet of the last reactor used to collect stable FEVE fluorocarbon resin products.

[0021] Furthermore, the material transfer between the reactor and the tubular reactor is controlled by a transfer pump or by valves using pressure difference or liquid level difference.

[0022] Furthermore, the material transfer between adjacent reactors is controlled by pumps or valves using pressure or level differences.

[0023] Furthermore, material transfer between adjacent tubular reactors is controlled by pumps or valves using differential pressure.

[0024] Furthermore, the delivery pump includes, but is not limited to, gear pumps, screw pumps, plunger pumps, cycloidal pumps, and diaphragm pumps.

[0025] Furthermore, the residence time of the material in a single reactor (= effective volume of the reactor / feed rate) is controlled within 10 min to 3 h, that is, the residence time of the material in a single reactor is controlled within 10 min to 3 h, and the residence time of the material in a single tubular reactor is controlled within 10 min to 3 h.

[0026] Preferably, the residence time of the material in a single reactor is controlled within 30 min to 2 h, that is, the residence time of the material in a single reaction vessel is controlled within 30 min to 2 h, and the residence time of the material in a single tubular reactor is controlled within 30 min to 2 h.

[0027] Furthermore, the total residence time for the polymerization reaction is 1 h to 25 h.

[0028] Preferably, the total polymerization residence time is 3h to 22h.

[0029] More preferably, the total polymerization residence time is 6h to 16h.

[0030] Furthermore, the continuous polymerization process is carried out at a certain reaction temperature, with the initial reactor having a reaction temperature of 50~70℃ and the subsequent reactor having a reaction temperature of 71~100℃.

[0031] Preferably, the reaction temperature in the initial reactor is 50~65℃, and the reaction temperature in the subsequent reactor is 75~90℃.

[0032] Furthermore, the continuous polymerization process is carried out under a certain reaction pressure. The pressure range is related to the type of gaseous monomer and the reaction formulation, and is generally controlled at 0.2~2 MPa. That is, the pressure of the prepolymerization reaction is 0.2~2 MPa, and the pressure of the postpolymerization reaction is 0.2~2 MPa.

[0033] Preferably, the reaction pressure is controlled at 0.3~1.5 MPa, that is, the pressure of the prepolymerization reaction is 0.3~1.5 MPa, and the pressure of the postpolymerization reaction is 0.3~1.5 MPa.

[0034] Furthermore, the reactor or continuous polymerization reaction can be a liquid-liquid phase full-boiler reaction or a gas-liquid phase reaction, that is, the prepolymerization reaction or continuous polymerization reaction is a liquid-liquid phase full-boiler reaction or a gas-liquid phase reaction, and the postpolymerization reaction is a liquid-liquid phase full-boiler reaction or a gas-liquid phase reaction.

[0035] Furthermore, by controlling the liquid level in the reactor, the utilization rate of the reactor equipment for continuous polymerization is generally controlled at 70% to 98%.

[0036] Preferably, the utilization rate of the reactor equipment used for continuous polymerization is controlled at 80% to 95%.

[0037] Furthermore, the equipment utilization rate of the reactor is 70%~98%, and the equipment utilization rate of the reactor is controlled by controlling the liquid level of the reactor; the equipment utilization rate of the tubular reactor is 70%~98%, and the equipment utilization rate of the tubular reactor is controlled by controlling the liquid level of the tubular reactor.

[0038] Preferably, the equipment utilization rate of the reactor is 80% to 95%; the equipment utilization rate of the tubular reactor is 80% to 95%.

[0039] Furthermore, the solvent is an organic solvent, which may be one or more of xylene, toluene, ethyl acetate, butyl acetate, acetone, butanone, tetrahydrofuran, ethylene glycol dimethyl ether, propylene glycol methyl ether acetate, etc.

[0040] Furthermore, the fluorinated gaseous monomer is selected from one or more of tetrafluoroethylene, trifluorochloroethylene, fluoroethylene, vinylidene fluoride, hexafluoropropylene, HFO-1234ze, and HFO-1234yf.

[0041] Further, the hydrocarbon liquid phase monomer is an alkyl vinyl ether or an alkyl vinyl ester, selected from one or more monomers such as ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, octyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether, dodecyl vinyl ether, cyclobutyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyhexyl vinyl ether, hydroxydecyl vinyl ether, hydroxydodecyl vinyl ether, hydroxyhexadecyl vinyl ether, hydroxycyclopropyl vinyl ether, hydroxycyclobutyl vinyl ether, hydroxycyclopentyl vinyl ether, hydroxycyclohexyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, perfluoron-propyl vinyl ether, perfluorobutyl vinyl ester, vinyl acetate, and isopropyl acetate.

[0042] Further, the initiator is an organic peroxide initiator, which is selected from one or more of the following: tert-butyl peroxyneodecanate, bis(4-tert-butylcyclohexyl peroxydicarbonate), tert-butyl peroxypentanoate, dilauroyl peroxy, didecanoyl peroxy, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxypentanoate, and tert-pentylneovale peroxy.

[0043] Furthermore, the FEVE fluorocarbon resin prepared by the continuous polymerization method (a method involving a reactor and a tubular reactor in series) exhibits product performance comparable to or better than that obtained by batch polymerization, and possesses superior performance stability. The FEVE fluorocarbon resin prepared by the continuous polymerization method shows significantly higher CPK values ​​for various indices between different batches compared to batch polymerization, as well as superior aging resistance, storage time, and heat resistance. Moreover, the continuous polymerization method yields resins with better performance than batch polymerization resins. Additionally, the method of connecting a reactor and a tubular reactor in series combines the advantages of both methods, resulting in high monomer utilization, strong heat exchange capacity, good quality stability, ease of automation, low energy consumption, and suitability for various scales of production.

[0044] Furthermore, the method employs a combination of a reaction vessel and a tubular reactor for continuous polymerization.

[0045] A second objective of the present invention is to provide a tubular and batch mixing apparatus for realizing the continuous polymerization method of the FEVE fluorocarbon resin, comprising an initial reactor and a subsequent reactor; the initial reactor being one or more reactors connected in series and / or one or more tubular reactors connected in series; the subsequent reactor being one or more reactors connected in series and / or one or more tubular reactors connected in series; the initial reactor and the subsequent reactor being connected in series.

[0046] Furthermore, both the reactor and the tubular reactor are equipped with inlets and outlets.

[0047] Furthermore, the last initial reactor is connected to the first subsequent reactor via a pipeline, adjacent reactors are connected via pipelines, and adjacent tubular reactors are connected via pipelines. The pipelines can be equipped with a delivery pump or valves to control material delivery using pressure difference or liquid level difference.

[0048] Furthermore, by combining a reaction vessel and a tubular reactor, a complete reaction system capable of continuous feeding, continuous polymerization, and continuous discharge is formed. Simultaneously, it is applicable to various stages from pilot-scale to industrial-scale production, depending on the feed rate and equipment scale.

[0049] It should be noted that the device and process principle of the present invention are universal, and their application scope is not limited to FEVE fluorocarbon resin, but can also be extended to the synthesis of other types of resins.

[0050] Compared with the prior art, the beneficial effects of the present invention are reflected in the following aspects: 1) Compared with the traditional batch polymerization technology, the continuous polymerization method of FEVE fluorocarbon resin and the tubular and batch mixing device of the present invention, based on the original batch reaction equipment and process, realizes the continuous production process of FEVE fluorocarbon resin, with minimal impact on product quality changes, but the product stability and consistency are far higher than the original batch reaction.

[0051] 2) Compared with the traditional batch polymerization technology, the continuous polymerization method of FEVE fluorocarbon resin and the tubular and batch mixing devices of the present invention have a higher utilization rate of fluorinated gaseous monomers in the continuous polymerization of FEVE fluorocarbon resin. The actual excess addition of fluorinated gaseous monomers is 100.5~101% of the theoretical amount, while in the batch process, the actual excess addition of fluorinated gaseous monomers is often up to 105% of the theoretical amount.

[0052] 3) Compared with the traditional batch polymerization technology, the continuous polymerization method of FEVE fluorocarbon resin and the tubular and batch mixing devices of the present invention have the advantages of continuous monomer feeding, continuous polymerization reaction, controllable polymerization heat, basically constant heat release and heat release range, small reaction temperature fluctuation, simpler temperature control, high controllability of polymerization reaction process, and more stable quality of polymer product.

[0053] 4) Compared with the traditional batch polymerization technology, the continuous polymerization method of FEVE fluorocarbon resin and the tubular and batch mixing device of the present invention apply the tubular reactor in the stage of high heat release. By utilizing the high heat exchange capacity of the tubular reactor, high heat release polymerization reaction that is difficult to carry out in a reactor can be realized.

[0054] 5) Compared with the traditional batch polymerization technology, the continuous polymerization method of FEVE fluorocarbon resin and the tubular and batch mixing device of the present invention avoid the repeated heating and cooling process of the traditional batch polymerization, resulting in lower energy consumption, better process stability and higher degree of automation. Attached Figure Description

[0055] Figure 1 This is a schematic diagram of the tubular and batch mixing apparatus used in the continuous polymerization method of FEVE fluorocarbon resin in Examples 1 and 4 of the present invention.

[0056] Figure 2 This is a schematic diagram of the tubular and batch mixing apparatus used in the continuous polymerization method of FEVE fluorocarbon resin of Example 2 according to the present invention.

[0057] Figure 3 This is a schematic diagram of the tubular and batch mixing apparatus used in the continuous polymerization method of FEVE fluorocarbon resin of Example 3 according to the present invention. As indicated by the markings in the diagram: 1. First reaction vessel, 2. Second reaction vessel, 3. First tubular reactor, 4. Liquid phase discharge valve; 5. Second tubular reactor, 6. Third reaction vessel, 7. Third tubular reactor, 8. Fourth Reactor 9. Fourth tubular reactor, a. Hydrocarbon liquid-phase monomers b. Fluorine-containing gaseous monomers c. Solvents, etc. e. Crude FEVE fluorocarbon resin. Detailed Implementation

[0058] The present invention will be further described in detail below with reference to specific embodiments, but this is by no means a limitation thereof. Any preparation methods, materials, structures, or composition ratios not explicitly described in this technical solution are considered common technical features disclosed in the prior art.

[0059] In this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may change. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0060] It should be noted that in this invention, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0061] This invention relates to a continuous polymerization method for FEVE fluorocarbon resin and tubular and batch mixing apparatuses. Specifically, it relates to a method for continuous polymerization of FEVE fluorocarbon resin using batch and tubular reactors. The method mainly includes: continuously adding fluorine-containing gaseous monomers, hydrocarbon liquid monomers, initiators, additives, and solvents to a pre-reactor according to a specific formulation ratio for material mixing and prepolymerization. The material level in the initial reactor is monitored as needed. When a suitable level is reached, the material continuously enters the subsequent tubular reactor for further reaction. After normal continuous operation, the prepolymerization reaction takes place in the initial reactor, maintaining a certain temperature and pressure. If the reactor is a batch reactor, the liquid level also needs to be maintained. The pre-reacted material continuously enters the subsequent reactor at a constant rate for further polymerization. Finally, the crude FEVE fluorocarbon resin product is obtained from the outlet of the last subsequent reactor. Before the reaction begins, the reactor section is filled with solvent or finished resin to achieve a full-pipe state, realizing a continuous reaction process of continuous feeding, continuous polymerization, and continuous discharge. Compared with the traditional FEVE batch polymerization reaction, this device has strong heat exchange capacity, controls a constant feed rate, and its reaction exothermic rate and exothermic heat are constant values. The polymerization process is stable, highly continuous, and has excellent batch consistency.

[0062] This invention provides a continuous polymerization method for FEVE fluorocarbon resin and tubular and batch mixing devices, employing one or more reactors and one or more tubular reactors for small-scale and conventional production of continuous polymerization reactions. The method and equipment together constitute a polymerization process route capable of continuous feeding, continuous polymerization, and continuous discharge. The method includes the following steps: (1) Continuous feeding: The reaction raw materials are continuously fed into the initial reactor according to the formula ratio to carry out the prepolymerization reaction and the reaction material after the prepolymerization reaction is obtained by continuous polymerization. The material liquid level in the reactor is monitored and controlled to be maintained within the set range. (2) Continuous polymerization: The reactants after the prepolymerization reaction enter the post-polymerization reactor and undergo post-polymerization reaction to carry out continuous polymerization to obtain FEVE fluorocarbon resin products; (3) Continuous discharge: The crude FEVE fluorocarbon resin product after polymerization is collected at the outlet of the last reactor; The initial reactor is one or more reaction vessels and / or one or more tubular reactors; The post-reactor is one or more reaction vessels and / or one or more tubular reactors.

[0063] In some embodiments of the present invention, the method preferably includes the following steps: (1) Continuous feeding: The reaction raw materials are continuously fed into one or more reactors according to the formula ratio to carry out prepolymerization reaction and continuous polymerization to obtain the reaction material after prepolymerization reaction. The material liquid level in the reactor is monitored and controlled to be maintained within the set range. (2) Continuous polymerization: The reactants after the prepolymerization reaction enter one or more tubular reactors, and the postpolymerization reaction occurs to carry out continuous polymerization to obtain FEVE fluorocarbon resin products. (3) Continuous discharge: The crude FEVE fluorocarbon resin after polymerization is collected at the outlet of the last tubular reactor.

[0064] In some embodiments of the present invention, the reaction raw materials include fluorine-containing gaseous monomers and hydrocarbon liquid monomers, initiators, auxiliaries, and solvents.

[0065] In some embodiments of the present invention, the inlet of the reaction vessel or tubular reactor is connected to a feed pump and / or a pressure reducing valve and / or a regulating valve to control the feed rate of the reaction raw materials and keep the feed rate of the reaction raw materials constant.

[0066] In some embodiments of the present invention, the continuous feeding process controls the feed rate of the reactants using a feed pump or pressure reducing valve to maintain a constant feed rate. The feed rate depends on the size of the reactor, and the size of the reactor and the feed rate determine the residence time of the material in each reactor. No special requirements are made regarding the size of the reactor and the feed rate, but the residence time of the material needs to be limited to ensure the full progress of the polymerization reaction. In some embodiments of the present invention, the outlet of the final post-polymerization reactor is connected to a discharge pump and / or a back pressure valve and / or a regulating valve to control the discharge rate of the FEVE fluorocarbon resin product and maintain a constant discharge rate.

[0067] In some embodiments of the present invention, after the reactants have completed polymerization in the last tubular reactor, the resulting crude FEVE fluorocarbon resin product is discharged stably and continuously through a discharge control system (such as a regulating valve, back pressure valve, or discharge pump), ultimately obtaining a product with a high monomer conversion rate.

[0068] In some embodiments of the present invention, the continuous discharge process is controlled by the discharge valve (which can be a back pressure valve or a regulating valve) or discharge pump of the reactor to maintain a constant discharge rate of the FEVE fluorocarbon resin product and ensure that the liquid level in the reactor is within a reasonable range. The sustainability of liquid level control determines the capacity of the continuous polymerization equipment.

[0069] In some embodiments of the present invention, the number of the reaction vessels is 1-n, where 2≤n≤10.

[0070] In some embodiments of the present invention, the number of tubular reactors is 1-n, where 2≤n≤10.

[0071] In some embodiments of the present invention, the prepolymerization reaction of the continuous polymerization process is carried out in the initial reactor and maintained at a certain temperature and pressure. When the liquid level in the initial reactor reaches a set value, it begins to continuously enter the tubular reactor at a certain speed for the postpolymerization reaction. After normal continuous operation, the prepolymerization reaction is carried out in the initial reactor and maintained at a certain temperature and pressure. If the reactor is a kettle, the liquid level also needs to be maintained. The pre-reacted material continuously enters the post-polymerization reactor at a constant speed for the postpolymerization reaction.

[0072] In some embodiments of the present invention, the post-polymerization reaction of the continuous polymerization process is carried out in a post-reactor and maintained at a certain temperature and pressure.

[0073] In some embodiments of the present invention, the form, number, diameter, and length of the tubular reactors are mainly used to ensure the minimum flow rate, heat exchange efficiency, and required residence time of the material. Therefore, there are no specific requirements for the form, number, diameter, and length of the tubular reactors. The preferred number of tubular reactors is generally 2 to 30, with a diameter of φ5 to 200 mm and a length of 50 to 200 cm per reactor.

[0074] In some embodiments of the present invention, the mixing component within the tubular reactor primarily serves to rapidly and uniformly mix the materials, achieving an effect equivalent to the stirring paddle in a traditional reactor. No specific structure or style is limited; generally, a static support type, a filled type, or a dynamic stirring type is preferred. The tubular reactor is equipped with a mixing component used to rapidly and uniformly mix the materials; the mixing component can be a static support type, a filled type, or a dynamic stirring type.

[0075] In some embodiments of the present invention, multiple reactors (reaction vessels or tubular reactors) are connected in sequence, wherein the inlet of the first reactor is connected to the outlet of the reactor, the inlet of the subsequent reactor is connected to the outlet of the previous reactor, and the outlet of the last reactor is used to collect a stable FEVE fluorocarbon resin product.

[0076] In some embodiments of the present invention, the material transfer between the reaction vessel and the tubular reactor is controlled by a transfer pump or by using valves to control the pressure difference or liquid level difference.

[0077] In some embodiments of the present invention, material transfer between adjacent reactors is controlled by pumps or valves using differential pressure or level. Material transfer between adjacent tubular reactors is controlled by pumps or valves using differential pressure.

[0078] In some embodiments of the present invention, the delivery pump includes, but is not limited to, gear pumps, screw pumps, plunger pumps, cycloidal pumps, and diaphragm pumps.

[0079] In some embodiments of the present invention, the residence time of the material in a single reactor (= effective volume of reactor / feed rate) is controlled to be 10 min to 3 h, that is, the residence time of the material in a single prepolymerization reactor 1 is controlled to be 10 min to 3 h, and the residence time of the material in a single postpolymerization reactor is controlled to be 10 min to 3 h.

[0080] In some embodiments of the present invention, the residence time of the material in a single reactor (= effective volume of the reactor / feed rate) is controlled within 10 min to 3 h, that is, the residence time of the material in a single reactor is controlled within 10 min to 3 h, and the residence time of the material in a single tubular reactor is controlled within 10 min to 3 h.

[0081] In some embodiments of the present invention, the residence time of materials in a single reactor is controlled to be 30 min to 2 h, that is, the residence time of materials in a single reaction vessel is controlled to be 30 min to 2 h, and the residence time of materials in a single tubular reactor is controlled to be 30 min to 2 h.

[0082] In some embodiments of the present invention, the total polymerization residence time is 1 h to 25 h.

[0083] In some embodiments of the present invention, the total polymerization reaction residence time is 3h to 22h.

[0084] In some embodiments of the present invention, the total polymerization residence time is 6h to 16h.

[0085] In some embodiments of the present invention, the continuous polymerization process is carried out at a certain reaction temperature, with the initial reaction temperature in the reactor being 50~70°C and the subsequent reaction temperature in the reactor being 71~100°C.

[0086] In some embodiments of the present invention, the reaction temperature in the initial reactor is 50~65°C, and the reaction temperature in the subsequent reactor is 75~90°C.

[0087] In some embodiments of the present invention, the continuous polymerization process is carried out under a certain reaction pressure. The pressure range is related to the type of gaseous monomer and the reaction formulation, and is generally controlled at 0.2~2 MPa. That is, the pressure of the prepolymerization reaction is 0.2~2 MPa, and the pressure of the postpolymerization reaction is 0.2~2 MPa.

[0088] In some embodiments of the present invention, the reaction pressure is controlled at 0.3 to 1.5 MPa, that is, the pressure of the prepolymerization reaction is 0.3 to 1.5 MPa, and the pressure of the postpolymerization reaction is 0.3 to 1.5 MPa.

[0089] In some embodiments of the present invention, the reactor (reaction vessel or tubular reactor) can be a liquid-liquid phase full-bottle reaction or a gas-liquid phase reaction.

[0090] In some embodiments of the present invention, by controlling the utilization rate of the reactor level control equipment, the reactor equipment utilization rate for continuous polymerization is generally controlled at 70% to 98%. Preferably, the reactor equipment utilization rate for continuous polymerization is controlled at 80% to 95%.

[0091] In some embodiments of the present invention, the equipment utilization rate of the reactor is 70% to 98%, and the equipment utilization rate of the reactor is controlled by controlling the liquid level of the reactor; the equipment utilization rate of the tubular reactor is 70% to 98%, and the equipment utilization rate of the tubular reactor is controlled by controlling the liquid level of the tubular reactor. Preferably, the equipment utilization rate of the reactor is 80% to 95%; the equipment utilization rate of the tubular reactor is 80% to 95%.

[0092] In some embodiments of the present invention, taking the initial reactor as a reactor vessel and the subsequent reactor as a tubular reactor (or alternatively: the initial reactor as a tubular reactor and the subsequent reactor as a reactor vessel), the method includes the following steps: (1) Weigh different proportions of hydrocarbon liquid phase monomers, add a certain amount of solvent and additives, stir and mix evenly, and then place them in a liquid phase monomer tank.

[0093] (2) The hydrocarbon liquid phase monomer is a vinyl ester or vinyl ether monomer, selected from one or more of ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, octyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether, dodecyl vinyl ether, cyclobutyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyhexyl vinyl ether, hydroxydecyl vinyl ether, hydroxydodecyl vinyl ether, hydroxyhexadecyl vinyl ether, hydroxycyclopropyl vinyl ether, hydroxycyclobutyl vinyl ether, hydroxycyclopentyl vinyl ether, hydroxycyclohexyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, perfluoron-propyl vinyl ether, perfluorobutyl vinyl ester, vinyl acetate, and isopropyl acetate. The specific monomer ratio is determined according to the polymerization formulation requirements of FEVE fluorocarbon resin and is not specifically limited.

[0094] (3) The solvent is one or more of xylene, toluene, ethyl acetate, butyl acetate, tetrahydrofuran, acetone, butanone, ethylene glycol dimethyl ether, and propylene glycol methyl ether acetate.

[0095] (4) The initiator is an organic peroxide initiator selected from one or more of the following: tert-butyl peroxynedecanoate, bis(4-tert-butylcyclohexyl peroxydicarbonate), tert-butyl peroxypentanoate, dilauryl peroxy, didecyl peroxy, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxypentanoate, and tert-pentyl neopentanoate peroxy.

[0096] (5) The adjuvant is one or more of triethylamine, ethanolamine, diethanolamine, hydroquinone, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, 1-(methyl)-8-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and Tinuvin® 292.

[0097] (6) The ratio of the above hydrocarbon liquid phase monomers to additives and solvents is not specifically limited and is determined according to the polymerization formulation requirements of FEVE resin.

[0098] (7) The fluorine-containing gaseous monomer is a fluorine-containing olefin, which is filled in a steel cylinder and is selected from one or more of tetrafluoroethylene, trifluorochloroethylene, fluoroethylene, vinylidene fluoride, hexafluoropropylene, HFO-1234ze, and HFO-1234yf.

[0099] (8) The mixed hydrocarbon liquid-phase monomer and initiator are continuously added to the first reactor 1 in a certain proportion using a plunger metering pump. The fluorinated gaseous monomer is continuously added to the pre-reactor at a constant speed or pressure using a volumetric metering pump or a pressure reducing valve. The ratio of the hydrocarbon liquid-phase monomer to the fluorinated gaseous monomer is 1:1 to 1.2 (molar ratio), preferably 1:1.005 to 1.01. The proportion of the initiator is determined according to the polymerization formulation requirements of FEVE fluorocarbon resin. By weight, the amount is generally 0.2% to 1% of the monomer amount (total amount of hydrocarbon liquid-phase monomer and fluorinated gaseous monomer).

[0100] (9) The pre-reacted material is continuously fed into the first tubular reactor 3 through the discharge valve or discharge pump for continuous polymerization reaction. In some embodiments of the present invention, the first reactor 1 and the second reactor 2 (or more, or only the first reactor 1) carry out pre-polymerization reaction at a polymerization temperature of 50-70 ℃, preferably 50-65 ℃, and the first tubular reactor 3 (or more) carry out post-polymerization reaction at a polymerization temperature of 71-100 ℃, preferably 75-90 ℃.

[0101] (10) The polymerization reaction pressure is kept constant by adding gaseous monomers through the fluorine-containing gaseous monomer replenishment valve in the reactor section, while the polymerization reaction pressure is controlled by the feed pump and the discharge valve in the tubular reactor section. The prepolymerization and postpolymerization reaction pressures are constant and are generally controlled at 0.2-2 MPa, preferably 0.3-1.5 MPa. The specific pressure depends on the type of fluorine-containing gaseous monomer.

[0102] (11) FEVE fluorocarbon resin crude product is obtained by continuous polymerization, continuously discharged, collected and then post-processed and concentrated to obtain FEVE fluorocarbon resin finished product, and related resin performance analysis and testing are carried out.

[0103] The testing methods for solid content, viscosity, acid value, hydroxyl value, and fluorine content of FEVE fluorocarbon resin are based on the "Explanatory Notes (Draft for Comments) on Solvent-Based Fluorinated Vinyl Ether (Ester) Copolymer (FEVE) Resin". Specifically, the following processes are included: 1. Solid content test Dry the small aluminum cup to constant weight, cool it, and weigh it, recording the weight as W1 (unit: g). After tareing the balance, add about 1g of resin sample to the aluminum cup, weigh it, and record the weight as W2 (unit: g). Place the aluminum cup containing the sample in a forced-air drying oven to dry for 1 hour, remove it, cool it, and weigh it again, recording the weight as W3 (unit: g). Calculate the solid content Wt (unit: %) according to formula (1): (1).

[0104] 2. Viscosity test Place the sample in a cylindrical container and keep it at 25°C for more than 2 hours; select LV-03 (63)# rotor and set the test conditions of digital rotary viscometer: rotation speed 60 rpm, test time 90 seconds, and record the test results after the reading stabilizes.

[0105] 3. Acid value test Weigh 10g of sample into a glass beaker, add toluene-ethanol mixture, shake well to completely dissolve the sample, and add bromophenol blue indicator; titrate with 0.1mol / L KOH standard solution to the endpoint, and calculate the acid value X according to formula (2). 酸 (Unit: mgKOH / g): (2), In the formula: V—Volume of KOH standard solution consumed in the titration, in mL; Concentration of c-KOH standard solution, unit: mol / L; m—sample mass, in g; N V —Sample solid content, unit:%.

[0106] 4. Hydroxyl value test Weigh an appropriate amount of sample into a flat-bottomed flask, add the acetylation reagent and catalyst, shake well to completely dissolve the resin, let stand, add deionized water, and heat under reflux for 10 min; after cooling, add an appropriate amount of pyridine and ethanol, and add phenolphthalein indicator; titrate with 0.6 mol / L KOH standard solution to the endpoint, and perform a blank experiment at the same time. Calculate the hydroxyl value X according to formula (3). 羟 (Unit: mgKOH / g): (3), In the formula: V2—The volume of KOH standard solution used in the titration of the sample, in mL; V1—Volume of KOH standard solution used for titrating the blank sample, in mL; Concentration of c-KOH standard solution, unit: mol / L; m—sample mass, in g; NV—Sample solid content, unit:%.

[0107] 5. Fluorine content test Weigh 1.5~2.0 mg of resin sample, decompose it by combustion, and absorb it with deionized water; add 2.5 mL of glycine-sodium perchlorate buffer solution (pH=3.35) and 20 drops of 0.05% methyl thyme complex methanol indicator, and titrate with 0.01 mol / L thorium nitrate standard solution to the endpoint (the solution changes from yellow to light blue), while performing a blank experiment. Calculate the fluoride content X according to formula (4). F (unit:%): (4), In the formula: V4—Volume of thorium nitrate standard solution used for titrating the sample, in mL; V3—Volume of thorium nitrate standard solution used for titrating the blank sample, in mL; c—Concentration of thorium nitrate standard solution, unit: mol / L; m — Sample mass, unit: g.

[0108] like Figure 1As shown, in some embodiments of the present invention, a tubular and batch mixing apparatus is used to implement the continuous polymerization method of the FEVE fluorocarbon resin. The tubular and batch mixing apparatus includes a first reactor 1, a second reactor 2, and a first tubular reactor 3 connected in sequence to the second reactor 2. The first reactor 1 is connected to the second reactor 2; the first reactor 1, the second reactor 2, and the first tubular reactor 3 are all provided with inlets and outlets. The first reactor 1 and the second reactor 2 are connected by pipelines, and the second reactor 2 and the first tubular reactor 3 are connected by pipelines. A delivery pump or valve can be installed on the pipelines to control material transport using pressure or level differences. Material is fed into the first reactor 1 through the inlet and discharged from the second tubular reactor 3 through a liquid phase discharge valve 4. Relevant materials are added to the pipeline between the first reactor 1 and the second reactor 2 as needed or according to the formulation.

[0109] like Figure 2 As shown, in some embodiments of the present invention, a tubular and batch mixing apparatus for implementing the continuous polymerization method of the FEVE fluorocarbon resin includes a second tubular reactor 5, a third reactor 6 connected to the second tubular reactor 5, and a third tubular reactor 7 connected to the third reactor 6, all connected in sequence. The second tubular reactor 5, the third reactor 6, and the third tubular reactor 7 each have an inlet and an outlet. The second tubular reactor 5, the third reactor 6, and the third tubular reactor 7 are connected in sequence by pipelines, which may be equipped with a transfer pump or valves to control material transport using pressure or level differences. Material is fed into the second tubular reactor 5 through the inlet and discharged from the third tubular reactor 7 through a liquid phase discharge valve 4. Relevant materials are added to the pipeline between the second tubular reactor 5 and the third reactor 6 as needed or according to the formulation.

[0110] like Figure 3 As shown, in some embodiments of the present invention, a tubular and batch mixing apparatus is used to implement the continuous polymerization method of the FEVE fluorocarbon resin. The tubular and batch mixing apparatus includes a fourth reactor 8 and a fourth tubular reactor 9 connected in sequence to the fourth reactor 8. Both the fourth reactor 8 and the fourth tubular reactor 9 have inlets and outlets. The fourth reactor 8 and the fourth tubular reactor 9 are connected in sequence by pipelines, which may be equipped with a transfer pump or valves to control material transport using pressure or level differences. Material is fed into the fourth reactor 8 through the inlet and discharged from the fourth tubular reactor 9 through a liquid phase discharge valve 4. Relevant materials are added to the pipeline at the inlet of the fourth reactor 8 as needed or according to the formulation.

[0111] Example 1 like Figure 1As shown, this embodiment provides a continuous polymerization method for FEVE fluorocarbon resin, using the above-described method and apparatus.

[0112] Specifically, the device includes a first reaction vessel 1, a second reaction vessel 2, and a first tubular reactor 3 connected in sequence to the second reaction vessel 2, and a liquid phase discharge valve 4 connected to the outlet of the first tubular reactor 3.

[0113] The fluorine-containing gaseous monomer is trifluorochloroethylene, with a designed solid content of 64.6%. The tubular section (i.e., the first tubular reactor 3) uses seven DN25 static support rods, each with an effective length of 1.5 meters and an effective volume of approximately 0.6 L. They are installed in series at the downstream end of the reaction.

[0114] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, and xylene were pre-mixed in a ratio of 226:368:350:12:1114 (by weight) to obtain a mixed liquid phase. Tert-butyl peroxyneodecaate was continuously and stably added to a 0.5L reactor 1 at a ratio of 2070:12 (by weight) at a rate of 1249 g / h, and trichlorofluoroethylene at a rate of approximately 670 g / h for prepolymerization. The internal temperature was controlled at 54 °C, and the pressure was controlled at 5 bar using a trichlorofluoroethylene feed pressure reducing valve. The 0.5L reactor 1 maintained a constant pressure of 9 bar through a discharge valve. The overflow from the discharge valve entered a 20L reactor 2, with the pressure controlled at 5 bar using a trichlorofluoroethylene feed pressure reducing valve. The internal temperature is controlled at 54℃. The prepolymerized material is fed into the first tubular reactor 3 through the discharge valve (the liquid level is maintained between 75% and 85% by a capacitive level gauge). The internal temperature is controlled at 80℃. The pressure of the first tubular reactor 3 is controlled at 8 bar through the liquid phase discharge valve 4. The material stays in the first tubular reactor 3 for about 2 hours. At the outlet of the liquid phase discharge valve 4, crude FEVE fluorocarbon resin with a solid content of about 62.3% can be continuously collected. The reaction yield is 96.4% (the yield change is <0.2% when sampling at 1-hour intervals after 10 hours after stabilization).

[0115] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0116] Example 2 like Figure 2 As shown, this embodiment provides a continuous polymerization method for FEVE fluorocarbon resin, based on the above method and apparatus, with the following differences: Specifically, the device includes a second tubular reactor 5, a third reaction vessel 6, a third tubular reactor 7 connected in sequence, and a liquid phase discharge valve 4 connected to the outlet of the third tubular reactor 7.

[0117] The gaseous monomer is trifluorochloroethylene, with a designed solid content of 64.6%. Two additional DN25 statically supported tubular reactors (serving as the second tubular reactor 5) are used before the pre-reaction vessel (third reactor 6). Each reactor is 20cm long, with an effective volume of 0.08L, and a total residence time of approximately 4.8 minutes. The subsequent reaction section (i.e., the third tubular reactor 7) uses seven DN25 statically supported tubular reactors, each with an effective length of 1.5 meters and an effective volume of approximately 0.6L, installed in series.

[0118] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, and xylene were premixed in a ratio of 226:368:350:12:1114 to obtain a mixed liquid phase. The mixed liquid phase and tert-butyl peroxynedecanoate were continuously and stably fed into the second tubular reactor 5 at a ratio of 2070:12 at a rate of 1249 g / h, and trichlorofluoroethylene at a rate of approximately 670 g / h for prepolymerization reaction. The internal temperature was controlled at 54°C, and the pressure of the tubular reactor was kept constant at 15 bar using the discharge valve. The material was expected to stay in the second tubular reactor 5 for 4 minutes. Then, the material overflowing from the discharge valve entered the 20L third reactor 6) for prepolymerization reaction. The pressure was controlled at 5 bar using a trichlorofluoroethylene feed pressure reducing valve. The internal temperature is controlled at 54℃. The prepolymerized material is fed into the third tubular reactor 7 through the discharge valve (the liquid level is maintained between 75% and 85% by a capacitive level gauge). The internal temperature is controlled at 80℃. The pressure of the third tubular reactor 7 is controlled at 8 bar through the liquid phase discharge valve 4. The material stays in the third tubular reactor 7 for about 2 hours. At the outlet of the liquid phase discharge valve 4, crude FEVE fluorocarbon resin with a solid content of about 62.5% can be continuously collected. The reaction yield is 96.7% (the yield change is <0.2% when sampling at 1-hour intervals after 10 hours after stabilization).

[0119] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0120] Example 3 like Figure 3 As shown, this embodiment provides a continuous polymerization method for FEVE fluorocarbon resin, using the above-described method and apparatus.

[0121] Specifically, the device includes a fourth reaction vessel 8 and a fourth tubular reactor 9 connected in sequence.

[0122] The gaseous monomer is tetrafluoroethylene, with a designed solid content of 55.3%. The post-reaction section (i.e., the fourth tubular reactor 9) uses eight DN25 static support brackets, each with an effective length of 1.5 meters and an effective volume of approximately 0.6L, installed in series.

[0123] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, and xylene were premixed in a ratio of 226:368:350:12:1540 to obtain a mixed liquid phase. The mixed liquid phase and tert-butyl peroxyneodecanate were continuously and stably fed into the 20L fourth reactor 8 at a ratio of 2496:10 and a total rate of 1016 g / h for prepolymerization reaction. Tetrafluoroethylene was fed using a pressure reducing valve to control the pressure at 3.5 bar. The internal temperature is controlled at 54℃. The prepolymerized material is fed into the fourth tubular reactor 9 through a discharge pump (the liquid level is maintained between 75% and 85% by a capacitive level gauge). The internal temperature is controlled at 75℃. The pressure of the fourth tubular reactor 9 is controlled at 2 bar by the liquid phase discharge valve 4. The material stays in the fourth tubular reactor 9 for about 3.2 hours. At the outlet of the liquid phase discharge valve 4, crude FEVE fluorocarbon resin with a solid content of about 53.4% ​​can be continuously collected. The reaction yield is 96.9% (the yield change is <0.2% when sampling at 1-hour intervals after 10 hours after stabilization).

[0124] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0125] Example 4 like Figure 1 As shown, this embodiment provides a continuous polymerization method for FEVE fluorocarbon resin, using the above-described method and apparatus.

[0126] Specifically, the device includes a first reaction vessel 1, a second reaction vessel 2, and a first tubular reactor 3 connected in sequence to the second reaction vessel 2, and a liquid phase discharge valve 4 connected to the outlet of the first tubular reactor 3.

[0127] The gaseous monomer is hexafluoropropylene, with a designed solid content of 64.5%. Five DN25 static support brackets are used, each with an effective length of 1.5 meters and an effective volume of approximately 0.6L, installed in series.

[0128] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, and xylene were premixed in a ratio of 226:368:350:10:1300 to obtain a mixed liquid phase. The mixed liquid phase and the initiator tert-butyl peroxyneodecanate were continuously pumped at a rate of approximately 594 g / h in a ratio of 2254:24. Hexafluoropropylene was continuously and stably fed into a 0.5L first reactor 1 at a rate of 393 g / h using a plunger pump. The pressure was controlled at 15 bar through the discharge valve of the 0.5L first reactor 1. The internal temperature is controlled at 57℃. The overflow material from the discharge valve enters the 20L second reactor 2. The pressure inside the 20L reactor is controlled at 8 bar through the discharge valve of the second reactor 2, and the internal temperature is also controlled at 57℃. Then, the material is sent to the first tubular reactor 3 through the discharge pump (the liquid level is kept between 75% and 85% by a capacitive level gauge). The internal temperature is controlled at 80℃. The pressure of the tubular reactor is controlled at 15 bar through the liquid phase discharge valve 4. The material stays in the first tubular reactor 3 for about 3 hours. At the outlet of the liquid phase discharge valve 4, crude FEVE fluorocarbon resin with a solid content of about 59.7% can be continuously collected. The reaction yield is 92.6% (the yield change is <1% when sampling at 1-hour intervals after 10 hours).

[0129] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0130] Comparative Example 1 The formula ratio is exactly the same as in Example 1, and the 5L reactor is used for one-time feeding.

[0131] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, xylene, tert-butyl peroxyneodecanate, and trifluorochloroethylene were added to a 5 L reactor in batches of 226 g, 368 g, 350 g, 12 g, 1114 g, 12 g, and 1200 g, respectively. The reactor temperature was then raised to 54 °C and maintained for 4 h. The temperature was then raised to 75 °C and maintained for 2 h. After cooling, the product was discharged, yielding crude FEVE fluorocarbon resin with a solid content of 58.8% and a yield of 91.0% (yield variation ±1.5% in 5 repeatability experiments).

[0132] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0133] Comparative Example 2 The formulation ratio is exactly the same as in Example 3, using a single reactor for one-time feeding of liquid-phase monomers and continuous replenishment of tetrafluoroethylene.

[0134] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, xylene, and tert-butyl peroxyneodecanate were added to a 5 L reactor in batches of 226 g, 368 g, 350 g, 12 g, 1540 g, and 10 g, respectively. Tetrafluoroethylene was then introduced to bring the reactor pressure to positive. The reactor temperature was then raised to 54 °C, and tetrafluoroethylene was added at a constant pressure of 3 bar. The reaction continued for approximately 4 h, after which the temperature was raised to 75 °C. Once the temperature reached 75 °C, the addition of tetrafluoroethylene was stopped, and the reaction was maintained at 75 °C for 2 h. After cooling, the product was discharged, yielding crude FEVE fluorocarbon resin with a solid content of 50.9% and a yield of 92.4% (yield variation ±1% in three repeatability experiments).

[0135] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0136] Comparative Example 3 The formulation ratio is exactly the same as in Example 4, and the liquid phase monomer is fed into a single reactor in one go.

[0137] Hydroxybutyl vinyl ether, cyclohexyl vinyl ether, ethyl vinyl ether, Tinuvin® 292, xylene, tert-butyl peroxyneodecaate, and hexafluoropropylene were added to a 5L reactor in batches of 203g, 331g, 315g, 9g, 1170g, 18g, and 1440g, respectively. The reactor temperature was then raised to 57°C and maintained for 6 hours. After adding 3g of initiator, the temperature was raised to 75°C and maintained for another 3 hours. After cooling, the product was discharged, yielding crude FEVE fluorocarbon resin with a solid content of 58.1% and a yield of 90.1% (yield variation ±2% in three repeatability experiments).

[0138] The crude FEVE fluorocarbon resin was concentrated to a solid content of about 65% before analysis. The analytical data are shown in Table 1.

[0139] Table 1. Analytical Data of FEVE Fluoropolymer Finished Product * Viscosity data was analyzed three times, and the average of the three analyses was taken as the integer value.

[0140] As shown in Table 1, the yield of crude FEVE fluorocarbon resin prepared by Examples 1, 2, and 3 was significantly higher than that of Comparative Examples 1, 2, and 3. The viscosity of crude FEVE fluorocarbon resin prepared by Examples 1, 2, and 3 was also significantly lower than that of Comparative Examples 1, 2, and 3. Although the acid value, hydroxyl value, and fluorine content were basically the same, the deviation of the reaction solid content of the methods in Examples 1, 2, and 3 was basically <1%, while the deviation of the reaction solid content of the methods in Comparative Examples 1, 2, and 3 was basically ±1~1.5~2%. Moreover, although the average values ​​of acid value and hydroxyl value of Examples 1, 2, 3, Comparative Examples 1, 2, and 3 were similar, the values ​​of multiple batches of Comparative Examples 1, 2, and 3 varied greatly, which is different from Examples 1, 2, and 3. Even if samples were taken at intervals of several days, the changes in the analytical data were not significant.

[0141] In addition, in Examples 1 and 2, the actual amount of fluorine-containing gaseous monomers fed was 100% of the theoretical value, and no excessive amount was added. The amount of fluorine-containing gaseous monomers fed was 106% in Comparative Example 1 and 110% in Comparative Example 2.

[0142] According to Examples 1-4, the molecular weight distribution (PDI) value of the product can be actively controlled as needed, with a wide control range.

[0143] The above description of the embodiments is provided to enable those skilled in the art to understand and use the invention. It will be apparent to those skilled in the art that various modifications can be made to these embodiments, and the general principles described herein can be applied to other embodiments without inventive effort. Therefore, the present invention is not limited to the above embodiments, and any improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the invention should be within the protection scope of the present invention.

Claims

1. A continuous polymerization method for FEVE fluorocarbon resin, characterized in that, The method includes the following steps: (1) Continuous feeding: The reaction raw materials are continuously fed into the initial reactor according to the formula ratio to carry out the prepolymerization reaction and the reaction material after the prepolymerization reaction is obtained by continuous polymerization. The material liquid level in the reactor is monitored and controlled to be maintained within the set range. (2) Continuous polymerization: The reactants after the prepolymerization reaction enter the post-polymerization reactor and undergo post-polymerization reaction to carry out continuous polymerization to obtain FEVE fluorocarbon resin products; (3) Continuous discharge: The crude FEVE fluorocarbon resin product after polymerization is collected at the outlet of the last reactor; The reaction raw materials include fluorine-containing gaseous monomers and hydrocarbon liquid monomers, initiators, auxiliaries, and solvents; The initial reactor is one or more reaction vessels and / or one or more tubular reactors; The post-reactor is one or more reaction vessels and / or one or more tubular reactors.

2. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The inlet of the initial reactor is connected to a feed pump and / or a pressure reducing valve and / or a regulating valve to control the feed rate of the reaction raw materials; The outlet of the last reactor is connected to a discharge pump and / or a back pressure valve and / or a regulating valve to control the discharge rate of the FEVE fluorocarbon resin product.

3. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The prepolymerization reaction is carried out in the initial reactor and maintained at a certain temperature and pressure. The pre-reacted material is continuously fed into the subsequent reactor at a constant rate for the subsequent polymerization reaction. The post-polymerization reaction takes place in a post-reactor and is maintained at a certain temperature and pressure.

4. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The number of tubular reactors is 2 to 30, with a diameter of φ5 to 200 mm and a length of 50 to 200 cm for each.

5. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The residence time of materials in a single reactor is controlled between 10 min and 3 h; The residence time of materials in a single tubular reactor is controlled between 10 min and 3 h. The total residence time for polymerization is 1 h to 25 h; The reaction temperature in the initial reactor is 50~70℃. The reaction temperature in the post-reactor is 71~100℃; The pressure of the prepolymerization reaction is 0.2~2 MPa; The pressure of the post-polymerization reaction is 0.2~2 MPa.

6. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The tubular reactor is equipped with a mixing component, which is used to mix the materials quickly and uniformly. The mixing component can be a static support type mixing component, a filling type mixing component, or a dynamic stirring type mixing component.

7. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The prepolymerization reaction or continuous polymerization reaction is a liquid-liquid phase full-boil reaction or a gas-liquid phase reaction; The equipment utilization rate of the reactor is 70%~98%, and the equipment utilization rate of the reactor is controlled by controlling the liquid level of the reactor.

8. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The material transfer between the reaction vessel and the tubular reactor is controlled by a transfer pump or by valves using pressure difference or liquid level difference. Material transfer between adjacent reactors is controlled by pumps or valves using pressure or level differences. Material transfer between adjacent tubular reactors is controlled by pumps or valves using differential pressure. The delivery pump is one or more of the following: gear pump, screw pump, plunger pump, cycloidal pump, and diaphragm pump.

9. The continuous polymerization method for FEVE fluorocarbon resin according to claim 1, characterized in that, The solvent is an organic solvent, which is one or more of xylene, toluene, ethyl acetate, butyl acetate, acetone, butanone, tetrahydrofuran, ethylene glycol dimethyl ether, and propylene glycol methyl ether acetate. The fluorinated gaseous monomer is selected from one or more of tetrafluoroethylene, trifluorochloroethylene, fluoroethylene, vinylidene fluoride, hexafluoropropylene, HFO-1234ze, and HFO-1234yf; The hydrocarbon liquid phase monomer is an alkyl vinyl ether or an alkyl vinyl ester, selected from one or more of the following: ethyl vinyl ether, propyl vinyl ether, butyl vinyl ether, hexyl vinyl ether, heptyl vinyl ether, octyl vinyl ether, decyl vinyl ether, dodecyl vinyl ether, hexadecyl vinyl ether, octadecyl vinyl ether, dodecyl vinyl ether, cyclobutyl vinyl ether, cyclopentyl vinyl ether, cyclohexyl vinyl ether, hydroxymethyl vinyl ether, hydroxyethyl vinyl ether, hydroxypropyl vinyl ether, hydroxybutyl vinyl ether, hydroxypentyl vinyl ether, hydroxyhexyl vinyl ether, hydroxydecyl vinyl ether, hydroxydodecyl vinyl ether, hydroxyhexadecyl vinyl ether, hydroxycyclopropyl vinyl ether, hydroxycyclobutyl vinyl ether, hydroxycyclopentyl vinyl ether, hydroxycyclohexyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, perfluoron-propyl vinyl ether, perfluorobutyl vinyl ester, vinyl acetate, and isopropyl acetate. The initiator is an organic peroxide initiator, which is selected from one or more of the following: tert-butyl peroxyneodecanate, bis(4-tert-butylcyclohexyl peroxydicarbonate), tert-butyl peroxypentanoate, dilauroyl peroxide, didecyl peroxide, tert-butyl peroxy-2-ethylhexanoate, tert-butyl peroxy-3,5,5-trimethylhexanoate, tert-butyl peroxypentanoate, and tert-pentylneovalerate peroxide. The adjuvant is one or more of triethylamine, ethanolamine, diethanolamine, hydroquinone, bis(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate, and 1-(methyl)-8-(1,2,2,6,6-pentamethyl-4-piperidinyl) sebacate.

10. A tubular and batch mixing apparatus for carrying out a continuous polymerization method of FEVE fluorocarbon resin as described in any one of claims 1-9, characterized in that, The tubular and batch mixing devices include the initial reactor and the subsequent reactor. The initial reactor is one or more reactors connected in series and / or one or more tubular reactors connected in series. The downstream reactor is one or more reactors connected in series and / or one or more tubular reactors connected in series. The initial reactor and the subsequent reactor are connected in series.

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