A method for producing a modified polyphenylene ether

Abstract

The application discloses a production method of modified polyphenyl ether and relates to the technical field of high polymer materials. The production method of the modified polyphenyl ether comprises the following steps: mixing 2,6-dimethylphenol, an organic solvent and a polymerization catalyst, introducing oxygen to perform an oxidative polymerization reaction, obtaining a first reaction liquid containing monohydroxyl polyphenyl ether, mixing the first reaction liquid with a coupling agent and the polymerization catalyst, introducing oxygen to perform an oxidative coupling reaction, obtaining a second reaction liquid containing dihydroxyl polyphenyl ether, adding a terminating agent to the second reaction liquid to terminate the reaction, and performing dehydration treatment to obtain a dehydrated reaction liquid, mixing the dehydrated reaction liquid with a modifier and a modification catalyst to perform a modification reaction, obtaining a modified polymer solution, and performing post-treatment on the modified polymer solution to obtain the modified polyphenyl ether. The production method of the modified polyphenyl ether provided by the application is used for reducing catalyst residue and residual hydroxyl content, optimizing a molecular weight distribution and improving product purity.

Description

Technical Field

[0001] This application relates to the field of polymer materials technology, and in particular to a method for producing modified polyphenylene ether. Background Technology

[0002] Polyphenylene oxide (PPO) is a high-performance engineering plastic with excellent thermal stability, mechanical strength, dimensional stability, low dielectric constant and low dielectric loss. It is widely used in electronics, automotive industry, aerospace, 5G communication, medical devices and other fields. Low molecular weight polyphenylene oxide has become a matrix resin for high-frequency and high-speed materials due to its short molecular chain and good processability.

[0003] Currently, solution polymerization is the primary method for preparing low molecular weight polyphenylene ethers. However, existing solution polymerization methods suffer from problems such as high catalyst residue, high residual hydroxyl content, wide molecular weight distribution, insufficient purity, and high intrinsic viscosity. Furthermore, current processes also face challenges related to high solvent consumption and difficulties in solvent recovery. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems. The purpose of this application is to provide a method for producing modified polyphenylene ether, which reduces catalyst residue and residual hydroxyl content, optimizes molecular weight distribution, and improves product purity.

[0005] This application provides a method for producing modified polyphenylene ether, comprising: 2,6-Dimethylphenol, organic solvent and polymerization catalyst are mixed and oxygen is introduced to carry out an oxidative polymerization reaction to obtain a first reaction solution containing monohydroxy polyphenyl ether. The first reaction solution is mixed with a coupling agent and a polymerization catalyst, and oxygen is introduced to carry out an oxidative coupling reaction to obtain a second reaction solution containing dihydroxy polyphenylene ether. The polymerization catalyst is a metal catalyst. The reaction is terminated by adding a terminator to the second reaction solution, and then dehydration is performed to obtain the dehydrated reaction solution. The dehydrated reaction solution was mixed with a modifier and a modifying catalyst to carry out a modification reaction, resulting in a modified polymer solution. The modified polymer solution was post-treated to obtain modified polyphenylene ether.

[0006] Compared with the prior art, the technical solution provided in this application firstly utilizes segmented polymerization. In the oxidative polymerization stage, oxygen supply and a catalytic system guide the orderly growth of 2,6-dimethylphenol monomers to form monohydroxy polyphenylene ether, avoiding the problem of disordered molecular chain growth in traditional single polymerization. Then, in the oxidative coupling reaction stage, the directional bonding reaction between the coupling agent and the monohydroxy polyphenylene ether regulates the molecular chain structure, fundamentally narrowing the molecular weight distribution and reducing the generation of free residual hydroxyl groups. Secondly, this application rapidly terminates the reaction of the second reaction solution using a terminator, preventing the continuous occurrence of side reactions. Furthermore, by removing metal catalytic ions and polar impurities from the reaction system, catalyst residue is reduced in terms of material composition, avoiding the adverse effects of impurities on the product's heat resistance and dielectric properties. Next, by utilizing the high reactivity of the terminal hydroxyl groups of dihydroxy polyphenylene ether, chemical bonding occurs with the modifier. While fully preserving the inherent heat resistance, low dielectric constant, and high strength properties of polyphenylene ether, the molecular interface interaction is optimized by grafting functional groups, reducing the viscosity of the material, improving the processing rheological properties of the modified polyphenylene ether, and enhancing its matrix compatibility with other polymer materials.

[0007] Therefore, the production method of modified polyphenylene ether in this application not only reduces the content of catalyst residue and residual hydroxyl groups, optimizes the molecular weight distribution of the product, and improves the overall purity of the product, but also improves the material processing performance and blending compatibility, making the overall process more practical. Attached Figure Description

[0008] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 A process flow diagram of the modified polyphenylene ether production system provided in the first embodiment of this application; Figure 2 A process flow diagram of the modified polyphenylene ether production system provided in the second embodiment of this application; Figure 3 A process flow diagram of the modified polyphenylene ether production system provided in the third embodiment of this application; Figure 4 A flowchart illustrating the preparation process of modified polyphenylene ether provided in the embodiments of this application.

[0009] Figure label: 110 - First reaction unit; 111 - Polymerization reactor; 111a - 2,6-Dimethylphenol inlet; 111b - First organic solvent inlet; 111c - Polymerization catalyst inlet; 111d - First air inlet; 112 - First reaction circulation pump; 113 - First circulation cooler; 120 - Second reaction unit; 120a - Coupling agent inlet; 120b - Second organic solvent inlet; 120c - Second air inlet. 130 - Separation unit, 131 - Water separator, 131a - Demineralized water inlet, 132 - Liquid phase separation device, 132a - Oil phase outlet, 132b - Aqueous phase outlet, 140 - Modification reaction unit, 141 - Modification reactor, 141a - Catalyst inlet, 141b - Modifier inlet, 142 - Second reaction circulation pump, 143 - Second circulation cooler, 150 - Post-treatment unit, 151 - Catalyst recovery device, 1511 - Catalyst recovery tower, 1512 - Catalyst recovery tower top condenser, 1513 - Catalyst recovery tower top reflux tank, 1514 - Catalyst recovery tower bottom transfer pump, 1515 - Catalyst recovery tower bottom condenser, 153 - First precipitation device, 1521 - First stage precipitation vessel, 1522 - Second stage precipitation vessel, 153 - First filtration device, 154 - Dissolution device, 155 - Second precipitation device, 156 - Second filtration device, 157 - Second dissolving device, 158-Third precipitation device, 159-Third filtration device, 160-End sealing unit, 160a-Terminator inlet, 170-Wastewater tank, 180-Concentration unit, 181-Concentration tower, 182-Concentration tower top condenser, 183-Concentration tower top reflux tank, 184-Concentration tower bottom transfer pump, 185-Concentration tower bottom condenser, 190-Finished product storage tank, 200-First collection unit, 210-Second collection unit. Detailed Implementation

[0010] To make the technical problems, technical solutions, and beneficial effects to be solved by this application clearer, the following detailed description is provided in conjunction with embodiments. It should be understood that the specific embodiments described herein are merely illustrative of this application and are not intended to limit this application.

[0011] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise expressly specified. "Several" means one or more, unless otherwise expressly specified.

[0012] In the description of this application, it should be understood that the terms "upper", "lower", "front", "rear", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0013] It should be noted that, in this application, the terms "exemplary" or "for example" are used to indicate that something is being described as an example, illustration, or illustration. Any embodiment or design described as "exemplary" or "for example" in this application should not be construed as being more preferred or advantageous than other embodiments or design solutions. Specifically, the use of terms such as "exemplary" or "for example" is intended to present the relevant concepts in a concrete manner.

[0014] In this application, "at least one" means one or more, and "more than one" means two or more. "And / or" describes the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can mean: A alone, A and B simultaneously, or B alone, where A and B can be singular or plural. The character " / " generally indicates that the preceding and following related objects are in an "or" relationship. "At least one of the following" or similar expressions refer to any combination of these items, including any combination of single or plural items. For example, at least one of a, b, or c can mean: a, b, c, a combination of a and b, a combination of a and c, a combination of b and c, or a, b, and c, where a, b, and c can be single or multiple.

[0015] Polyphenylene oxide (PPE) is a high-performance polymer material with outstanding comprehensive properties such as excellent thermal stability, good mechanical properties, low dielectric constant, and low dielectric loss, showing great application potential in many fields such as electronics, aerospace, and automotive. Among them, low molecular weight PPE, due to its shorter molecular chain and good processability, has become a matrix resin for high-frequency and high-speed materials.

[0016] Currently, the main methods for synthesizing low molecular weight polyphenylene ethers include solution polymerization, emulsion polymerization, and bulk polymerization. Among them, solution polymerization has the advantages of mild reaction conditions, easy control, and high product purity, making it the most widely used synthesis route.

[0017] However, traditional solution polymerization processes still have the following problems: On the one hand, polyphenylene ether (PPE) molecular chains are prone to disordered growth, resulting in a wide molecular weight distribution and high residual hydroxyl content in the product, affecting the dielectric stability and processing consistency. On the other hand, the residual metal catalyst used in the reaction system is difficult to completely remove, and the copper ions remaining in the product will degrade the heat resistance and dielectric properties of the material, making it difficult to meet the high purity requirements of high-end electronic packaging materials. In addition, PPE itself has high melt viscosity, poor processing fluidity, and poor compatibility with other matrix resins (such as epoxy resin), limiting its widespread application in fields such as high-frequency copper-clad laminates.

[0018] To address the aforementioned issues, this application provides a method for producing modified polyphenylene ether, which can narrow the molecular weight distribution, reduce residual hydroxyl groups and catalyst residues, improve product purity, and simultaneously improve processing fluidity and compatibility with other resins, while retaining the inherent excellent properties of polyphenylene ether to meet the application needs of high-end fields.

[0019] Figure 1 A process flow diagram of the production system for modified polyphenylene ether according to a first embodiment of this application is shown. Figure 1 As shown, the production system includes: a first reaction unit 110, a second reaction unit 120, a separation unit 130, a modification reaction unit 140, and a post-processing unit 150. The outlet of the first reaction unit 110 is connected to the inlet of the second reaction unit 120, the outlet of the second reaction unit 120 is connected to the inlet of the separation unit 130, the outlet of the separation unit 130 is connected to the inlet of the modification reaction unit 140, and the outlet of the modification reaction unit 140 is connected to the inlet of the post-processing unit 150.

[0020] The first reaction unit 110 of this application embodiment is used to convert 2,6-dimethylphenol into a first reaction solution containing monohydroxy polyphenylene ether under the action of a catalyst. The second reaction unit 120 is used to convert the first reaction solution containing monohydroxy polyphenylene ether into a second reaction solution containing dihydroxy polyphenylene ether under the action of a coupling agent. The separation unit 130 is used to remove the aqueous phase and metal ions from the second reaction solution to obtain a dehydrated reaction solution. The modification reaction unit 140 is used to modify the dehydrated reaction solution to obtain a modified polymer solution. The post-processing unit 150 is used to post-process the modified polymer solution to obtain modified polyphenylene ether.

[0021] In one alternative embodiment, the first reaction unit 110 includes a polymerization reactor 111, a first reaction circulation pump 112, a first circulation cooler 113, and an oxygen analyzer (not shown in the figure). The outlet of the polymerization reactor 111 is connected to the inlet of the first reaction circulation pump 112, the outlet of the first reaction circulation pump 112 is connected to the inlet of the first circulation cooler 113, and the outlet of the first circulation cooler 113 is connected to the return port of the polymerization reactor 111. The polymerization reactor also has a gas phase outlet, and the oxygen analyzer is located at the gas phase outlet of the polymerization reactor 111.

[0022] For example, the first circulating cooler 113 described above can be at least one of a shell-and-tube heat exchanger, a plate heat exchanger, or a coaxial heat exchanger. The shell side of the first circulating cooler 113 is circulated with a heat exchange medium, while the tube side carries the reaction liquid. The heat exchange medium includes cooling water or chilled water, used to remove heat from the reaction liquid.

[0023] In one feasible embodiment, the first reaction unit 110 includes a 2,6-dimethylphenol inlet 110a, a first organic solvent inlet 110b, a polymerization catalyst inlet 110c, and a first gas inlet 110d. The 2,6-dimethylphenol inlet 110a is used to supply 2,6-dimethylphenol raw material into the first reaction unit 110. The first organic solvent inlet 110b is used to introduce organic solvent into the first reaction unit 110. The polymerization catalyst inlet 110c is used to add polymerization catalyst into the first reaction unit 110. The first gas inlet 110d is used to introduce oxygen and / or nitrogen into the first reaction unit 110. Oxygen acts as an oxidant in the polymerization reaction, and nitrogen acts as a protective gas. The oxygen concentration in the reaction system can be controlled by adjusting the nitrogen flow rate, thus avoiding excessive oxygen leading to an overly vigorous reaction or disordered product structure.

[0024] It should be noted that the aforementioned first air inlet 110d is connected to both the nitrogen pipeline and the oxygen pipeline. Depending on the reaction stage and operating conditions, nitrogen or oxygen can be introduced separately, or nitrogen and oxygen can be mixed in proportion to achieve flexible control of the reaction atmosphere and ensure the stable and safe conduct of the oxidative polymerization reaction.

[0025] For example, the organic solvent used in the first reaction unit 110 includes at least one of toluene, xylene, and benzene, preferably toluene. The polymerization catalyst includes a copper-based catalyst, preferably a copper salt-amine complex catalyst, wherein the copper salt is selected from at least one of cuprous chloride, cuprous bromide, and copper sulfate, and the amine is selected from at least one of pyridine, diethylamine, triethylamine, and butylamine. Specifically, the copper salt-amine complex catalyst can be at least one of cuprous chloride-triethylamine complex, cuprous bromide-pyridine complex, and copper sulfate-diethylamine complex.

[0026] For example, the polymerization reactor 111 also has a jacket disposed on its outer wall. The jacket is used to circulate a heat exchange medium to control the reaction temperature inside the polymerization reactor 111. The heat exchange medium circulating in the jacket includes cooling water or heat transfer oil, which can be switched according to the needs of the reaction process. When heating is required in the initial stage of the reaction, heat transfer oil is introduced into the jacket for heating. When heat removal is required during the reaction process, cooling water is switched in the jacket for cooling. The jacket works in conjunction with the external circulation cooling system to maintain the temperature inside the polymerization reactor 111 within the range of 10°C to 50°C.

[0027] The aforementioned gas phase outlet is connected to the tail gas treatment system. The tail gas generated during the reaction (including unreacted oxygen, nitrogen, and possibly entrained organic solvent vapors) is discharged from the polymerization reactor through the gas phase outlet and enters the tail gas treatment system for treatment.

[0028] The polymerization reactor 111 is also equipped with a stirrer, which is used to stir and mix the materials in the polymerization reactor 111 so that 2,6-dimethylphenol, organic solvent, catalyst and oxygen are in full contact, thereby promoting the uniform progress of the oxidative polymerization reaction.

[0029] In one alternative embodiment, the second reaction unit 120 has a coupling agent inlet 120a, a second organic solvent inlet 120b, and a second air inlet 120c. The coupling agent inlet 120a is used to supply coupling agent into the second reaction unit 120, the second organic solvent inlet 120b is used to introduce organic solvent into the first reaction unit 110, and the second air inlet 120c is used to introduce oxygen and / or nitrogen into the first reaction unit 110. Oxygen participates in the polymerization reaction as an oxidant, and nitrogen is used as a protective gas. The oxygen concentration in the reaction system can be controlled by adjusting the amount of nitrogen introduced.

[0030] It should be noted that the aforementioned second air inlet 120c is connected to both the nitrogen and oxygen pipelines. Depending on the reaction stage and operating conditions, nitrogen or oxygen can be introduced separately, or nitrogen and oxygen can be mixed in proportion to allow for flexible control of the reaction atmosphere and ensure the stable and safe conduct of the oxidative polymerization reaction.

[0031] For example, the organic solvent used in the second reaction unit 120 includes at least one of toluene, xylene, and benzene, preferably toluene. The coupling agent includes a bisphenol compound, which includes at least one of bisphenol A, bisphenol C, or bisphenol F.

[0032] For example, the second reaction unit 120 described above is a coupling reactor. The coupling reactor has a jacket disposed on the outer wall. The jacket is used to circulate a heat exchange medium to control the reaction temperature inside the coupling reactor. The heat exchange medium circulating inside the jacket includes cooling water or heat transfer oil.

[0033] For example, the coupling reactor described above also has a stirrer inside, which is used to stir and mix the materials in the coupling reactor, so that the reaction solution of monohydroxy polyphenylene ether, coupling agent, catalyst and introduced oxygen are in full contact, and promote the uniformity of oxidative coupling reaction.

[0034] In some examples, the second reaction unit 120 also has a gas phase outlet connected to a tail gas treatment system. The tail gas generated during the reaction (including unreacted oxygen, nitrogen, and possibly entrained organic solvent vapors) is discharged from the coupled reactor through the gas phase outlet and enters the tail gas treatment system for processing. An oxygen analyzer is also installed at this gas phase outlet to monitor the oxygen concentration in the outlet tail gas in real time.

[0035] In some examples, the modified polyphenylene ether production system of this application embodiment further includes a capping unit 160, which is provided with a terminator inlet 161a. The outlet of the second reaction unit 120 is connected to the inlet of the capping unit 160, and the outlet of the capping unit 160 is connected to the inlet of the separation unit 130.

[0036] For example, the above-mentioned end-sealing unit 160 is an end-sealing reactor. The end-sealing reactor 161 has a jacket disposed on the outside of the vessel wall. The jacket is used to circulate heat exchange medium to control the reaction temperature. The end-sealing unit 160 also has a stirrer inside.

[0037] For example, the terminator mentioned above includes a chelating agent, which includes at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and hypozoxytriacetic acid, preferably ethylenediaminetetraacetic acid.

[0038] In some examples, the separation unit 130 of this application embodiment includes a water separator 131 and a liquid phase separation device 132. The water separator 131 is provided with a demineralized water inlet 131a. The outlet of the sealing unit 160 is connected to the inlet of the water separator 131. The outlet of the water separator 131 is connected to the inlet of the liquid phase separation device 132. The outlet of the liquid phase separation device 132 is connected to the inlet of the modified reaction unit 140.

[0039] For example, the modified polyphenylene ether production system of this application embodiment also includes a wastewater tank 170. The outlet of the aforementioned water separator 131 is also connected to the inlet of the wastewater tank 170. The aforementioned liquid phase separation device 132 is a liquid-liquid separator with an oil phase outlet 132b and an aqueous phase outlet 132c. The oil phase outlet 132b is connected to the inlet of the modification reaction unit 140 and is used to transport the separated oil phase reaction liquid to the modification reaction unit 140. The aqueous phase outlet 132c is connected to the inlet of the wastewater tank 170.

[0040] For example, the liquid phase separation device 132 described above can be a disc centrifuge or a tubular centrifuge.

[0041] In some examples, the modified polyphenylene ether production system of this application embodiment further includes a concentration unit 180, the outlet of the separation unit 130 is connected to the inlet of the concentration unit 180, and the outlet of the concentration unit 180 is connected to the inlet of the modification reaction unit 140.

[0042] For example, the liquid phase separation device 132 is connected to the inlet of the concentration unit 180. The dehydrated reaction liquid can be transported to the concentration unit 180 for concentration treatment through the outlet of the liquid phase separation device 132.

[0043] In some examples, the concentration unit 180 has a recovered solvent outlet that is connected to the solvent inlet of the first reaction unit 110.

[0044] For example, the concentration unit 180 includes a concentration tower 181, a top condenser 182, and a top reflux tank 183. The top outlet of the concentration tower is connected to the inlet of the top condenser 182, the outlet of the top condenser 182 is connected to the inlet of the top reflux tank 183, the outlet of the top reflux tank 183 is connected to the top reflux port of the concentration tower 181, and the outlet of the top reflux tank 183 is also connected to the organic solvent inlet 110b of the first reaction unit 110, realizing solvent recovery and reuse. The bottom outlet of the concentration tower 181 is connected to the inlet of the modification reaction unit 140. It should be understood that the outlet of the top reflux tank 183 is the recovered solvent outlet.

[0045] For example, the concentration unit 180 in this application embodiment also includes a concentration tower bottom transfer pump 184 and a concentration tower bottom condenser 185. The inlet of the concentration tower bottom transfer pump 184 is connected to the outlet of the concentration tower bottom, the outlet of the concentration tower bottom transfer pump 184 is connected to the inlet of the concentration tower bottom condenser 185, and the outlet of the concentration tower bottom condenser 185 is connected to the inlet of the modification reaction unit 140, for cooling the concentrated reaction liquid to a set temperature and stably delivering it to the subsequent units.

[0046] In some examples, the modified reaction unit 140 of this application embodiment includes a modified reactor 141, which has a catalyst inlet 141a and a modifier inlet 141b. The outlet of the concentration unit 180 is connected to the inlet of the modified reactor 141, and the outlet of the modified reactor 141 is connected to the inlet of the post-processing unit 150. The catalyst inlet 141a is used to introduce a catalyst into the modified reactor 141, and the modifier inlet 141b is used to introduce a modifier into the modified reactor 141.

[0047] For example, the modified catalyst described above includes an ester exchange catalyst or a basic catalyst, wherein the ester exchange catalyst includes a tin-based catalyst or a titanate catalyst. The tin-based catalyst includes dibutyltin dilaurate or stannous octoate. The titanate catalyst includes tetrabutyl titanate or tetraisopropyl titanate. The basic catalyst described above includes pyridine, 4-dimethylaminopyridine, or triethylamine. Preferably, the modified catalyst is 4-dimethylaminopyridine.

[0048] For example, the modifier described above includes methacrylic anhydride or unsaturated acid anhydride. Unsaturated acid anhydride includes at least one of acrylic anhydride, crotonic anhydride, or maleic anhydride. Preferably, the modifier is methacrylic anhydride.

[0049] For example, the modified reaction unit 140 further includes a second reaction circulation pump 142 and a second circulation cooler 143. The outlet of the modified reactor 141 is connected to the inlet of the second reaction circulation pump 142, the outlet of the second reaction circulation pump 142 is connected to the inlet of the second circulation cooler 143, and the outlet of the second circulation cooler 143 is connected to the return port of the modified reactor 141, thereby realizing material circulation and heat exchange and stabilizing the reaction temperature.

[0050] For example, the second circulating cooler 143 described above can be at least one of a shell-and-tube heat exchanger, a plate heat exchanger, or a coaxial heat exchanger. The shell side of the second circulating cooler 143 is circulated with a heat exchange medium, while the tube side carries the reaction liquid. The heat exchange medium includes cooling water or chilled water, used to remove heat from the reaction liquid.

[0051] In some examples, the post-processing unit 150 of this application embodiment includes a catalyst recovery device 151, a first precipitation device 152, a first filtration device 153, a first dissolution device 154, a second precipitation device 155, and a second filtration device 156 connected in sequence. The outlet of the modified reaction unit 140 is connected to the inlet of the catalyst recovery device 151, the outlet of the catalyst recovery device 151 is connected to the inlet of the first precipitation device 152, the outlet of the first precipitation device 152 is connected to the inlet of the first filtration device 153, the solid outlet of the first filtration device 153 is connected to the inlet of the first dissolution device 154, the outlet of the first dissolution device 154 is connected to the inlet of the second precipitation device 155, and the outlet of the second precipitation device 155 is connected to the inlet of the second filtration device 156. The first precipitation device 152, the first filtration device 153, the first dissolution device 154, the second precipitation device 155, and the second filtration device 156 are all equipped with undesirable solvent inlets for introducing undesirable solvents to achieve product precipitation and purification.

[0052] In some examples, the first precipitation device 152 and the second precipitation device 155 described above may be at least one of a precipitation vessel, a precipitation tank, or a crystallizer.

[0053] For example, both the first precipitation device 152 and the second precipitation device 155 described above have a jacket structure, which is used to introduce a cooling medium to maintain the internal temperature of the device at 0°C to 20°C. The cooling medium includes at least one of cooling water, chilled water, or an aqueous solution of ethylene glycol.

[0054] In some examples, both the first precipitation device 152 and the second precipitation device 155 are equipped with a stirrer. The stirrer is used to stir the material during the precipitation process to make the precipitated solid particles uniform in size and to prevent particle agglomeration.

[0055] In some examples, the first filtration device 153 and the second filtration device 156 described above can be at least one of a drum filter, a pressure drum filter dryer, a centrifuge, or a filter press. Preferably, using a drum filter allows for continuous filtration and washing operations, improving production efficiency.

[0056] In some examples, the above-mentioned dissolving device 154 is a dissolving tank or dissolving vessel. The dissolving device 154 is equipped with a stirrer, which is used to stir the material during the dissolving process so that the wet filter cake is fully dissolved in the organic solvent.

[0057] In some examples, the catalyst recovery device 151 described above has a recovered catalyst outlet connected to the catalyst inlet of the modified reaction unit 140.

[0058] In some examples, the catalyst recovery device 151 includes a catalyst recovery tower 1511, a catalyst recovery tower top condenser 1512, and a catalyst recovery tower top reflux tank 1513. The top outlet of the catalyst recovery tower 1511 is connected to the inlet of the catalyst recovery tower top condenser 1512, the outlet of the catalyst recovery tower top condenser 1512 is connected to the inlet of the catalyst recovery tower top reflux tank 1513, the outlet of the catalyst recovery tower top reflux tank 1513 is connected to the top reflux port of the catalyst recovery tower 1511, and the bottom outlet of the catalyst recovery tower 1511 is connected to the inlet of the first precipitation device 152. It should be understood that the outlet of the catalyst recovery tower top reflux tank 1513 is the catalyst recovery outlet.

[0059] In some examples, the catalyst recovery device 151 of this application embodiment further includes a catalyst recovery tower bottom delivery pump 1514 and a catalyst recovery tower bottom condenser 1515. The inlet of the catalyst recovery tower bottom delivery pump 1514 is connected to the outlet of the catalyst recovery tower bottom, the outlet of the catalyst recovery tower bottom delivery pump 1514 is connected to the inlet of the catalyst recovery tower bottom condenser 1515, and the outlet of the catalyst recovery tower bottom condenser 1515 is connected to the inlet of the first precipitation device 152.

[0060] In an alternative embodiment, the modified polyphenylene ether production system of this application further includes a finished product storage tank 190, and the outlet of the second filter device 156 is connected to the inlet of the finished product storage tank 190.

[0061] In an alternative embodiment, the modified polyphenylene ether production system of this disclosure further includes a first collection unit 200 and a second collection unit 210, wherein the filtrate outlet of the first filter device 153 is connected to the first collection unit 200, the filtrate outlet of the second filter device 156 is connected to the first collection unit 200, the washing liquid outlet of the first filter device 153 is connected to the second collection unit 210, and the washing liquid outlet of the second filter device 156 is connected to the second collection unit 210.

[0062] In some examples, the first collection unit 200 and the second collection unit 210 may be at least one of a collection tank, a collection vessel, or a collection pool, the volume of which is designed according to the production scale. The collected filtrate and washing liquid can be pumped to a solvent recovery unit for distillation separation and purification.

[0063] In other examples, Figure 2 A process flow diagram of a modified polyphenylene ether production system according to a second embodiment of this application is shown. Figure 2 As shown, the modified polyphenylene ether production system of this application embodiment is in Figure 1Based on the first embodiment, the post-processing unit 150 further includes a second dissolving device 157, a third precipitation device 158, and a third filtration device 159. The solid outlet of the second filtration device 156 is connected to the inlet of the second dissolving device 157, the outlet of the second dissolving device 157 is connected to the inlet of the third precipitation device 158, and the outlet of the third precipitation device 158 is connected to the inlet of the third filtration device 159. The second dissolving device 157, the third precipitation device 158, and the third filtration device 159 are all provided with undesirable solvent inlets. The filtrate outlet of the third filtration device 159 is connected to the first collection unit 180, the washing liquid outlet of the third filtration device 159 is connected to the second collection unit 210, and the solid outlet of the third filtration device 159 is the modified polyphenylene ether product outlet.

[0064] It should be noted that, Figure 2 The modified reaction unit and its upstream components, including the first reaction unit 110, the second reaction unit 120, the separation unit 130, the end-capping unit 160, and the concentration unit 180, are omitted. The structural composition of these units and their interconnections are not described in the provided text. Figure 1 The first embodiment shown is the same and will not be described again here.

[0065] In other examples, Figure 3 A process flow diagram of a modified polyphenylene ether production system according to a third embodiment of this application is shown. Figure 3 As shown, the modified polyphenylene ether production system of this application embodiment is in Figure 3 Based on the first embodiment, the post-processing unit 150 employs a two-stage series precipitation vessel for the first precipitation. Specifically, the first precipitation device 152 includes a first-stage precipitation vessel 1521 and a second-stage precipitation vessel 1522 connected in series, wherein the outlet of the first-stage precipitation vessel 1521 is connected to the inlet of the second-stage precipitation vessel 1522, and the outlet of the second-stage precipitation vessel 1522 is connected to the inlet of the first filtration device 153. Through two-stage series precipitation, the particle size distribution of the precipitated particles can be further controlled, improving the efficiency of subsequent filtration and washing.

[0066] It should be noted that, Figure 3 The modified reaction unit and its upstream components, including the first reaction unit 110, the second reaction unit 120, the separation unit 130, the end-capping unit 160, and the concentration unit 180, are omitted. The structural composition of these units and their interconnections are also omitted. Figure 1 The first embodiment shown is the same and will not be described again here.

[0067] In one feasible manner, embodiments of this application provide a method for producing modified polyphenylene ether, which utilizes... Figures 1-3 The production system, Figure 4A flowchart illustrating the preparation process of the modified polyphenylene ether according to an embodiment of this application is shown. Figure 4 As shown, the production method of modified polyphenylene ether in this application includes: Step 401: Mix 2,6-dimethylphenol, organic solvent and polymerization catalyst, and introduce oxygen to carry out oxidative polymerization reaction to obtain a first reaction solution containing monohydroxy polyphenyl ether.

[0068] For example, the reaction temperature of the above-mentioned oxidative polymerization reaction is 10℃~50℃, the reaction pressure is 0.01MPa~0.1MPa, and the reaction time is 1 hour~2 hours. Preferably, the reaction temperature is 10℃~20℃, the reaction pressure is 0.02MPa~0.05MPa, and the reaction time is 1.2 hours~1.8 hours.

[0069] In some examples, during the above-mentioned oxidative polymerization reaction, the volume concentration of oxygen in the reaction system is controlled to be less than or equal to 10% to 15%. When the volume concentration of oxygen in the reaction system is greater than 10% to 15%, the oxygen supply is cut off and nitrogen is introduced for replacement until the volume concentration of oxygen in the reaction system is less than or equal to 10% to 15%.

[0070] For example, the above-mentioned mixing of 2,6-dimethylphenol, organic solvent and polymerization catalyst, followed by oxidative polymerization under oxygen to obtain a first reaction solution containing monohydroxy polyphenylene ether, specifically includes: adding organic solvent to polymerization reactor, then adding 2,6-dimethylphenol and polymerization catalyst, mixing evenly, and purging oxygen under nitrogen protection to carry out oxidative polymerization to generate a first reaction solution containing monohydroxy polyphenylene ether.

[0071] Specifically, the organic solvent is first fed into the polymerization reactor, and stirring is started. Then, 2,6-dimethylphenol and the polymerization catalyst are fed into the polymerization reactor, while nitrogen is introduced into the reactor as a protective gas. The first reaction circulation pump is turned on, and the outlet temperature of the first circulation cooler is set to 10-50°C. The polymerization process is an exothermic reaction, and heat is removed through an external cooling system. When the material temperature in the polymerization reactor reaches 10-50°C, oxygen is introduced to begin the oxidative polymerization reaction. During the reaction, oxygen participates in the polymerization reaction as an oxidant, and oxygen is continuously introduced to maintain the oxidative environment required for the reaction. At the same time, the oxygen concentration in the polymerization reactor is controlled by adjusting the amount of nitrogen introduced as a balancing gas to avoid excessive oxygen, which could lead to an overly vigorous reaction or disordered product structure. After the reaction continues for 1-2 hours, the polymerization reaction is basically completed. The oxygen supply is stopped, and the valve of the nitrogen purging oxygen pipeline is opened to quickly replace the remaining oxygen in the entire reaction system with nitrogen, resulting in the first reaction solution containing monohydroxy polyphenylene ether.

[0072] The heat removal process of the aforementioned external circulation cooling system is as follows: The first reaction circulation pump is started to extract the reaction liquid from the bottom of the polymerization reactor and transport it to the inlet of the first circulation cooler. In the first circulation cooler, the reaction liquid exchanges heat with a heat exchange medium (e.g., cooling water). The cooled reaction liquid returns from the outlet of the first circulation cooler to the return port of the polymerization reactor. This cycle repeats, removing the reaction heat. By adjusting the flow rate and temperature of the heat exchange medium in the first circulation cooler, the reaction temperature inside the polymerization reactor can be controlled within the range of 10℃ to 50℃.

[0073] During the above reaction process, an oxygen analyzer can be used to monitor the oxygen concentration in the gas phase outlet of the polymerization reactor in real time. The oxygen concentration in the gas phase outlet should be controlled to be no higher than 10%~15%, preferably no higher than 10%~13%. When the oxygen volume concentration in the tail gas at the gas phase outlet exceeds 10%~15%, the oxygen supply and raw material feed should be immediately cut off, and a large amount of nitrogen should be introduced for replacement until the oxygen volume concentration in the reaction system is less than or equal to 10%~15%. This avoids the violent exothermic reaction, local overheating, and exacerbation of side reactions caused by excessively high oxygen concentration in the reaction system, prevents disordered molecular chain growth, widening of molecular weight distribution, and increased residual hydroxyl content, and avoids the safety risks caused by oxygen enrichment. It ensures that the oxidative polymerization reaction proceeds mildly and controllably, stably producing monohydroxy polyphenylene ether, ensuring a regular product structure, stable performance, and a safe and reliable production process.

[0074] For example, the heat exchange medium within the jacket of the aforementioned polymerization reactor can be switched as needed. When heating is required in the initial stage of the reaction, heat transfer oil is introduced into the jacket for heating; when heat removal is required during the reaction, cooling water is switched to the jacket for cooling. The jacket works in conjunction with the external circulation cooling system to maintain a stable temperature within the polymerization reactor.

[0075] In this application, during the oxidative polymerization stage, 2,6-dimethylphenol monomer is mixed with a polymerization catalyst, oxygen is introduced, and the oxidative polymerization reaction is carried out under mild conditions. This allows the monomer to polymerize in an orderly manner to generate monohydroxy polyphenylene ethers with hydroxyl groups at the ends of the molecular chains. By controlling the reaction temperature, oxygen concentration, and reaction time, the degree of polymerization of the monomer can be regulated in this stage, avoiding excessively high or low polymerization levels, thus ensuring a narrow molecular weight distribution of the monohydroxy polyphenylene ethers.

[0076] For example, the organic solvent mentioned above includes at least one of toluene, xylene, and benzene, preferably toluene. The polymerization catalyst mentioned above includes a copper-based catalyst, preferably a copper salt-amine complex catalyst, wherein the copper salt is selected from at least one of cuprous chloride, cuprous bromide, and copper sulfate, and the amine is selected from at least one of pyridine, diethylamine, triethylamine, and butylamine. Specifically, the copper salt-amine complex catalyst can be at least one of cuprous chloride-triethylamine complex, cuprous bromide-pyridine complex, and copper sulfate-diethylamine complex.

[0077] Step 402: Mix the first reaction solution with the coupling agent and polymerization catalyst, and introduce oxygen to carry out an oxidative coupling reaction to obtain a second reaction solution containing dihydroxy polyphenylene ether.

[0078] For example, the reaction temperature of the above-mentioned oxidative coupling reaction is 10℃~50℃, the reaction pressure is 0.01MPa~0.1MPa, and the reaction time is 1 hour~2 hours. Preferably, the reaction temperature is 10℃~20℃, the reaction pressure is 0.02MPa~0.05MPa, and the reaction time is 1.2 hours~1.8 hours.

[0079] In some examples, during the above oxidative coupling reaction, the volume concentration of oxygen in the reaction system is controlled to be less than or equal to 10% to 15%. When the volume concentration of oxygen in the reaction system is greater than 10% to 15%, the oxygen supply is cut off and nitrogen is introduced for replacement until the volume concentration of oxygen in the reaction system is less than or equal to 10% to 15%.

[0080] For example, the above-mentioned mixing of the first reaction solution with the coupling agent and the polymerization catalyst, and the introduction of oxygen to carry out an oxidative coupling reaction to obtain a second reaction solution containing dihydroxy polyphenylene ether specifically includes: adding an organic solvent to the coupling reactor, adding the coupling agent and stirring evenly, introducing nitrogen gas into the coupling reactor, and then adding the first reaction solution containing monohydroxy polyphenylene ether obtained in step 401 and the polymerization catalyst into the coupling reactor, mixing evenly, and introducing oxygen under nitrogen protection to carry out an oxidative coupling reaction to generate a second reaction solution containing dihydroxy polyphenylene ether.

[0081] Specifically, the organic solvent is first fed into the coupling reactor and stirred. Then, the coupling agent is added to the coupling reactor and stirred until homogeneous. Nitrogen gas is then introduced into the coupling reactor. The first reaction solution containing monohydroxy polyphenylene ether obtained in step 401 and the polymerization catalyst are added to the coupling reactor and mixed thoroughly. Simultaneously, the coupling reactor is heated by introducing a heat-conducting medium into the jacket of the coupling reactor, raising the internal temperature to 10°C~50°C. Once the material temperature inside the coupling reactor stabilizes at 10°C~50°C, the nitrogen supply is stopped or reduced, and oxygen is introduced to begin the oxidative coupling reaction. During the reaction, oxygen acts as an oxidant in the coupling reaction, while nitrogen acts as a balancing gas to control the oxygen concentration in the coupling reactor, preventing excessive oxygen from causing an overly vigorous reaction or disordered product structure. The reaction is essentially complete after 1 to 2 hours. Subsequently, the oxygen supply is stopped, and the oxygen pipeline is purged with nitrogen to rapidly replace the residual oxygen in the system, yielding the second reaction solution containing dihydroxy polyphenylene ether.

[0082] During the above reaction process, an oxygen analyzer can be used to monitor the oxygen concentration at the gas phase outlet of the coupling reactor in real time, controlling the concentration to be no higher than 10%~15%, preferably no higher than 10%~13%. When the oxygen concentration in the tail gas exceeds the standard, the oxygen supply should be immediately cut off, the feed should be stopped, and a large amount of nitrogen should be introduced to replace it until the volume concentration of oxygen in the reaction system is less than or equal to 10%~15%. This can avoid the violent exothermic reaction, local overheating, and side reactions caused by oxygen enrichment, promote the directional coupling of monohydroxy polyphenylene ether to form dihydroxy polyphenylene ether, regulate the molecular chain structure, narrow the molecular weight distribution, and at the same time ensure the safety and controllability of the reaction and the stability of the product performance.

[0083] For example, the organic solvent used in step 402 includes at least one of toluene, xylene, and benzene, preferably toluene. The polymerization catalyst used is the same as that used in step 402. The coupling agent is a bisphenol compound, including at least one of bisphenol A, bisphenol C, or bisphenol F.

[0084] This application employs segmented polymerization. First, in the oxidative polymerization stage, oxygen supply and a catalytic system are used to guide the orderly growth of 2,6-dimethylphenol monomers to form monohydroxy polyphenylene ether, avoiding the problem of disordered molecular chain growth in traditional single polymerization. Then, in the oxidative coupling reaction stage, the directional bonding reaction between the coupling agent and the monohydroxy polyphenylene ether is used to regulate the molecular chain structure, fundamentally narrowing the molecular weight distribution and reducing the generation of free residual hydroxyl groups.

[0085] Step 403: Add a terminator to the second reaction solution to terminate the reaction, and perform dehydration treatment to obtain the dehydrated reaction solution.

[0086] For example, the above-mentioned method of adding a terminator to the second reaction solution to terminate the reaction and then dehydrating it to obtain a dehydrated reaction solution specifically includes: First, transferring the second reaction solution containing dihydroxy polyphenylene ether obtained in step 402 to a capping reactor, adding a chelating agent to the second reaction solution, and stirring at 10°C to 50°C for 10 min to 30 min. The chelating agent binds with the metal ions contained in the metal catalyst to terminate the reaction, resulting in a reaction solution after the reaction has been terminated. Then, the reaction solution after the reaction has been terminated is heated to 60°C to 90°C and stirred for 90 min to 120 min to remove some impurities from the reaction solution after the reaction has been terminated, resulting in a purified reaction solution. Next, the aqueous phase in the purified reaction solution is separated to obtain an oil phase. Subsequently, demineralized water is added to the oil phase to remove residual metal ions from the polymerization catalyst, resulting in a dehydrated reaction solution.

[0087] Specifically, the second reaction solution containing dihydroxy polyphenylene ether obtained in step 402 is transferred to a capping reactor through a pipeline, and stirring is started. A chelating agent is added to the capping reactor, the amount of which is 0.1% to 1.0% of the total mass of the second reaction solution, preferably 0.2% to 0.8%. The second reaction solution in the capping reactor is heated to 10°C to 50°C, preferably 10°C to 30°C, using the heat-conducting medium in the jacket of the capping reactor, and stirred for 10 to 30 minutes. The chelating agent forms a stable complex with the metal ions (mainly copper ions) in the reaction system, deactivating the polymerization catalyst, thereby terminating the polymerization reaction and preventing the continued occurrence of side reactions, resulting in a reaction solution after the reaction has been terminated.

[0088] After the reaction is terminated, the reaction solution is heated to 60℃~90℃, preferably 65℃~85℃, using the heat-conducting medium in the jacket of the end-capped reactor, and stirred for another 90 minutes~120 minutes at this temperature. During this process, quinone byproducts generated in the reaction solution (such as colored impurities like biphenylquinone) are thermally decomposed or transformed into other soluble substances, thereby achieving the purpose of removing quinone impurities. Removing quinone impurities can significantly reduce the color of the product, improve its appearance quality and purity, and yield a purified reaction solution.

[0089] After impurity removal, the purified reaction solution is transferred to a separatory tank via pipeline. The separatory tank is equipped with a sight glass and an interface controller for observing and monitoring the oil-water separation interface. The solution is allowed to stand in the separatory tank for 10-30 minutes to allow the aqueous and oil phases to separate naturally. Because the reaction solution contains the previously added chelating agent solution and the water generated during the reaction, after standing, an upper oil phase (containing the organic phase of polyphenylene ether) and a lower aqueous phase (containing the chelating agent, metal ion complexes, and water-soluble impurities) are formed. After separation, the lower aqueous phase is drained through the drain valve at the bottom of the separatory tank and sent to a wastewater tank for further treatment to obtain the separated oil phase.

[0090] To further remove residual metal ions and water-soluble impurities from the oil phase, demineralized water is added to the oil phase in the separator, at a volume of 10%–50% of the oil phase. Stirring and washing are then performed for 10–20 minutes to dissolve any residual metal ions (such as copper ions) in the demineralized water. After washing, the reaction solution is piped to a liquid-liquid separator for oil-water separation. The liquid-liquid separator utilizes centrifugal force generated by high-speed centrifugation to efficiently separate the oil and water phases. The separated water phase (containing metal ions and impurities) is sent to a wastewater tank, while the separated oil phase is the dehydrated reaction solution. This dehydrated reaction solution, containing dihydroxy polyphenylene ether and organic solvents (such as toluene), reduces catalyst residue in its composition, avoids the adverse effects of impurities on the product's heat resistance and dielectric properties, and provides high-quality raw materials for subsequent modification reactions.

[0091] For example, the terminator mentioned above includes a chelating agent, which includes at least one of ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetic acid, and hypozoxytriacetic acid, preferably ethylenediaminetetraacetic acid.

[0092] Step 404: Mix the dehydrated reaction solution with the modifier and the modifying catalyst to carry out the modification reaction and obtain the modified polymer solution.

[0093] For example, the above-mentioned method of mixing the dehydrated reaction solution with a modifier and a modifying catalyst to obtain a modified polymer solution specifically includes: first, mixing the dehydrated reaction solution obtained in step 403 with the modifying catalyst, heating to 45℃~60℃, adding the modifier, and reacting at 45℃~60℃ for 2.5 hours~3.5 hours to obtain a modified intermediate solution. Then, heating the modified intermediate solution to 65℃~85℃ and maintaining the temperature with stirring to obtain a modified polymer solution.

[0094] Specifically, the dehydrated reaction liquid obtained in step 403 is transported to the modified reactor through a pipeline, and stirring is started. A modified catalyst is added to the modified reactor, and at the same time, the material inside the modified reactor is heated to 45°C~60°C, preferably 45°C~55°C, through the jacket or external circulation cooling system outside the modified reactor, and maintained within this temperature range to obtain a reaction mixture containing the modified catalyst.

[0095] After the material temperature in the modified reactor stabilizes at 45℃~60℃, the modifier is slowly added to the reactor. Once the modifier is completely added, the reaction is continued with stirring at 45℃~60℃ for 2.5 to 3.5 hours. During this process, the hydroxyl groups at the ends of the polyphenylene ether molecular chains undergo esterification with methacrylic anhydride, generating modified polyphenylene ether with methacrylate groups at the ends. Through this modification reaction, unsaturated double bonds that can participate in subsequent cross-linking and curing are introduced at the ends of the polyphenylene ether molecular chains, thereby improving the compatibility of polyphenylene ether with other resins (such as epoxy resin) and enhancing its processing fluidity, resulting in a modified intermediate liquid.

[0096] To promote a more complete reaction and improve the conversion rate, the modified intermediate solution was further heated to 65℃~85℃, preferably 70℃~80℃, and stirred at this temperature for 0.5 hours~1.5 hours. At this temperature, the esterification reaction proceeded further in the forward direction, and the unreacted hydroxyl groups continued to react with the modifier, further increasing the degree of modification. After the stirring and temperature maintenance were completed, a modified polymer solution was obtained.

[0097] Through the above-mentioned modification reaction, the dihydroxy polyphenylene ether in the dehydrated reaction solution can be successfully modified into a modified polyphenylene ether with unsaturated end groups. The resulting modified polymer solution has a high degree of modification and a low residual hydroxyl content, providing high-quality raw materials for subsequent post-processing steps.

[0098] For example, the modified catalyst described above includes an ester exchange catalyst or a basic catalyst, wherein the ester exchange catalyst includes a tin-based catalyst or a titanate catalyst. The tin-based catalyst includes dibutyltin dilaurate or stannous octoate. The titanate catalyst includes tetrabutyl titanate or tetraisopropyl titanate. The basic catalyst described above includes pyridine, 4-dimethylaminopyridine, or triethylamine. Preferably, the modified catalyst is 4-dimethylaminopyridine.

[0099] For example, the modifier described above includes methacrylic anhydride or unsaturated acid anhydride. Unsaturated acid anhydride includes at least one of acrylic anhydride, crotonic anhydride, or maleic anhydride. Preferably, the modifier is methacrylic anhydride.

[0100] In some examples, the amount of the modified catalyst added is 0.01% to 0.5% of the total mass of the dehydrated reaction solution, preferably 0.05% to 0.3%. The amount of the modifier added is calculated based on the hydroxyl content in the dehydrated reaction solution. The molar ratio of the modifier to hydroxyl groups is 1:1 to 3:1, preferably 1.2:1 to 2:1. The modifier can be added dropwise, with the drop rate controlled to ensure a stable modification reaction and avoid localized overheating or excessively vigorous reactions.

[0101] In some examples, the above-mentioned modification reaction can be carried out under nitrogen protection to prevent oxygen and moisture in the air from adversely affecting the reaction, such as inhibiting esterification or causing side reactions.

[0102] It should be noted that the heat removal process of the external circulation cooling system of the above-mentioned modified reaction unit includes: starting the second reaction circulation pump to extract the reaction liquid from the bottom of the modified reactor and transport it to the inlet of the second circulation cooler. After the reaction liquid exchanges heat with cooling water and cools down in the second circulation cooler, it returns to the return port of the modified reactor from the outlet, and the cycle repeats to remove the heat of reaction. By adjusting the flow rate and temperature of the cooling medium, the reaction temperature in the modified reactor is controlled within the required temperature range.

[0103] Step 405: Post-process the modified polymer solution to obtain modified polyphenylene ether.

[0104] For example, the post-treatment of the modified polymer solution to obtain modified polyphenylene ether specifically includes: First, at a temperature of 0℃~20℃, the modified polymer solution obtained in step 404 is mixed with a poor solvent, and the residence time is less than 30 minutes, preferably 10 minutes~20 minutes, to precipitate and obtain a precipitated slurry. Then, the precipitated slurry is filtered to obtain a filter cake and a filtrate, and the filter cake is washed with a poor solvent to obtain a washed filter cake. Next, the washed filter cake is dissolved in an organic solvent to obtain a redissolved solution. Subsequently, the redissolved solution is used as the modified polymer solution, and the precipitation, filtration, and washing operations are repeated at least once to obtain a purified filter cake. Finally, the purified filter cake is dried to obtain modified polyphenylene ether.

[0105] Specifically, the modified polymer solution obtained in step 404 is piped to a first precipitation device (e.g., a precipitation vessel). The stirrer of the first precipitation device is started, and the temperature inside the device is controlled at 0°C to 20°C using a jacketed cooling system. While stirring, a poor solvent is slowly added to the first precipitation device. At the temperature of 0°C to 20°C, the solubility of the modified polyphenylene ether in the polymer solution in the poor solvent decreases significantly, and the modified polyphenylene ether gradually precipitates to form solid particles. The residence time is controlled to be less than 30 minutes to ensure that the precipitation process is fully completed, resulting in a precipitated slurry containing modified polyphenylene ether solid particles.

[0106] The precipitated slurry is transported through pipelines to the first filtration unit for solid-liquid separation. The separated filtrate (mainly a mixture containing organic solvents and undesirable solvents) is sent to the first collection unit to recover and recycle the organic solvents. The separated filter cake is crude modified polyphenylene ether. The filter cake is washed with undesirable solvents, with the washing liquid typically used at a volume of 1 to 3 times the filter cake volume. The washing liquid is sent to the second collection unit to remove residual organic solvents, unreacted modifiers, and low-molecular-weight impurities from the filter cake surface. The purity of the modified polyphenylene ether in the washed filter cake is significantly improved.

[0107] The washed and filtered wet slurry is coarsely dried using gas to form a wet filter cake. After unloading, the wet filter cake is sent to a dissolving device. Toluene is added to the dissolving device, stirring is started, and the temperature is raised to 40℃~60℃ to fully dissolve the filter cake and form a redissolved solution. The amount of toluene added should be such that the solid content of the redissolved solution is controlled between 10% and 30% to facilitate subsequent precipitation operations. The dissolving time is generally 30 minutes to 60 minutes to ensure complete dissolution of the filter cake.

[0108] Using the reconstituted solution as the modified polymer solution, repeat the precipitation, filtration, and washing process at least once (i.e., perform a second precipitation, filtration, and washing). The purpose of this repetition is to further remove residual impurities and improve product purity. In each repetition, parameters such as precipitation temperature, amount of undesirable solvent, and residence time can be the same as the first time or adjusted appropriately.

[0109] In some examples, the purified filter cake obtained from the last filtration can be dried with gas at a temperature not exceeding 140°C. After drying, the volatile component content of the solid product is ≤0.6wt%. After the solid product cools to room temperature, it is unloaded, packaged, and weighed to obtain the modified polyphenylene ether finished product.

[0110] For example, the aforementioned undesirable solvents include at least one of methanol, ethanol, and isopropanol, preferably methanol.

[0111] For example, the volume ratio of the modified polymer solution to the undesirable solvent is controlled at 1:1 to 1:5, preferably 1:2 to 1:4. The undesirable solvent can be added dropwise or in one go, preferably slowly dropwise, so that the precipitated solid particles have a uniform particle size, which is beneficial for subsequent filtration and washing operations.

[0112] In some examples, the above process of precipitation, filtration, washing, dissolution, and reprecipitation can be repeated 2 to 5 times, depending on the product purity requirements. The more repetitions, the higher the product purity, but the production time and cost will also increase accordingly. Therefore, a balance needs to be struck based on actual needs.

[0113] In an alternative embodiment, before mixing the modified polymer solution with a poor solvent to precipitate the product, the method further includes: subjecting the modified polymer solution to vacuum distillation and recovering the modifier and modified catalyst from the modified polymer solution.

[0114] Specifically, the modified polymer solution obtained in step 404 is transported to the catalyst recovery unit via pipeline. The vacuum system of the catalyst recovery tower is activated, and the pressure at the top of the tower is controlled at -60 kPaG to -75 kPaG. Simultaneously, the material in the bottom of the tower is heated, and the bottom temperature is controlled at 75℃ to 85℃, while the top temperature is controlled at 55℃ to 65℃. Under reduced pressure, unreacted modifiers (such as methacrylic anhydride) and some organic solvents in the modified polymer solution are vaporized by heating and rise to the top of the tower. The vapor at the top of the tower enters the condenser at the top of the catalyst recovery tower, where it exchanges heat with cooling water and condenses into a liquid state. The condensed mixture enters the reflux tank at the top of the catalyst recovery tower. Part of it is returned to the top of the catalyst recovery tower as reflux through the reflux pump to regulate the gas-liquid balance in the tower, while the other part is collected as recovered modifiers and solvents, which can be returned to the modification reactor for recycling as needed. The modified polymer solution obtained in the bottom of the catalyst recovery tower after removing the modifier and some solvent is pumped out by the bottom pump of the catalyst recovery tower, cooled to 45°C~55°C by the bottom heat exchanger of the catalyst recovery tower, and then transported to the post-processing unit (e.g., the first precipitation device) for subsequent precipitation treatment.

[0115] For example, the catalyst recovery device described above can form a loop with the modified reactor to return the recovered modifier and / or modified catalyst to the modified reactor for recycling, thereby further improving the utilization rate of raw materials and economic efficiency.

[0116] In one feasible embodiment, the modified polyphenylene ether of this application has a number-average molecular weight ≤3000 g / mol, a molecular weight distribution index D <1.8, metal residue ≤0.5 ppm, residual hydroxyl content <60 ppm, and purity ≥99.9%. It is evident that the modified polyphenylene ether prepared in this application has a low molecular weight and narrow distribution, which can reduce melt viscosity, improve processing rheological properties, enhance compatibility with other polymer materials, and has low impurity content, effectively avoiding the adverse effects of impurities on the material's heat resistance and dielectric properties, ensuring stable and excellent product performance, and meeting the stringent application requirements of high-end electronics, copper-clad laminates, and other fields.

[0117] As can be seen from the above, the production method of modified polyphenylene ether in this application embodiment, through segmented polymerization, first forms monohydroxy polyphenylene ether in the oxidative polymerization stage, and then forms hydroxy polyphenylene ether in the oxidative coupling stage. After treatment with a chelating agent and washing with desalinated water, residual metal catalyst is effectively removed. Combined with a purification process involving multiple precipitation, dissolution, and reprecipitation, low molecular weight modified polyphenylene ether products can be directly obtained from the raw material 2,6-dimethylphenol. This method simplifies the lengthy preparation process of traditional processes, reduces the polyphenylene ether solution treatment steps, and achieves high production efficiency and large capacity. Some raw materials in the by-products can be recycled and reused, effectively reducing production costs and offering advantages in energy conservation and emission reduction. The resulting product has a controllable and uniform molecular weight distribution, excellent compatibility with PCB matrix resins, few by-products, low metal residue, and advantages such as low dielectric constant, low dielectric loss, low moisture absorption, and good processing performance. It is an ideal matrix resin for preparing copper-clad laminates and has broad market application prospects. Meanwhile, the process described in this application is simple to operate and fits the actual production needs. Simulation verification shows that it can stably meet the industrial production requirements of low molecular weight modified polyphenylene ether.

[0118] Example 1 Example 1 of this application provides a method for producing modified polyphenylene ether, applying... Figure 1 The production system for modified polyphenylene ether includes: The first step involves feeding 24 kg of toluene into a 50 L polymerization reactor. After feeding, the reactor agitator is activated. Then, 2.25 kg of 2,6-dimethylphenol is added to the reactor, along with di-n-butylamine containing cuprous oxide as a catalyst. Simultaneously, nitrogen is introduced into the reactor, and the first reaction circulation pump is activated, setting the outlet temperature of the first circulation cooler to 10–50 °C. The polymerization process is exothermic, and heat is removed via an external cooling system. When the material temperature inside the reactor reaches 10–50 °C, oxygen is introduced, with nitrogen used as a balancing gas. An online oxygen analyzer is used to monitor and control the oxygen concentration in the outlet exhaust gas to ensure it does not exceed 10–15 v%. The reaction mixture begins polymerization under thorough stirring and mixing. During the reaction, the reactor operates at a slightly positive pressure, at a temperature of 10–50 °C, and for 60–120 minutes. When the oxygen content in the reactor exceeds the set limit of 10–15 v%, the oxygen supply and concentrated solution feed are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system. Stop the agitator of the polymerization reactor and continue to supply nitrogen to prepare for the transfer of the reaction liquid to the coupling reactor.

[0119] The second step involves feeding 4 kg of toluene into the coupling reactor. After feeding, the reactor agitator is activated, and then 0.42 kg of bisphenol A coupling agent is added. Simultaneously, nitrogen gas is introduced into the reactor. The polymerization process is exothermic, and the reaction temperature is maintained between 10 and 50°C through cooling via the external jacket of the coupling reactor. When the material temperature inside the coupling reactor falls below 10–50°C, the catalyst and the reaction liquid in the polymerization reactor are added, while oxygen is introduced. Nitrogen is used as a balancing gas, and the oxygen concentration in the outlet tail gas is monitored and controlled using an online oxygen analyzer to ensure it does not exceed 10–15 v%. The coupling polymerization reaction begins under thorough stirring and mixing. During the reaction, the pressure in the coupling reactor is 0.01–0.1 MPa(G), the operating temperature is 10–50°C, and the reaction time is 60–120 min. When the oxygen content in the coupling reactor exceeds the set limit of 10–15 v%, the oxygen supply and the feed of the reaction liquid are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system, and then stop the agitator of the coupling reactor.

[0120] Third, after transferring the reaction solution from the coupling reactor to the end-capping reactor, turn on the stirrer of the end-capping reactor, add the prepared chelating agent to the end-capping reactor, stir evenly, terminate the polymerization reaction, and maintain the temperature inside the end-capping reactor at approximately 20~50℃, stirring evenly for 10~30 minutes. After the set time is reached, raise the temperature of the end-capping reactor to 60~90℃, maintain the temperature, and stir evenly for 90~120 minutes. After the reaction reaches the set time, stop the stirrer of the end-capping reactor, stop heating, and allow the reaction solution in the end-capping reactor to flow by gravity into the water separator for further water separation and centrifugation.

[0121] The fourth step involves transferring the reaction liquid from the end-capped reactor to a water separator and allowing it to stand for a certain period to allow for oil-water separation. The bottom aqueous phase is then transferred to a wastewater tank, where a certain amount of demineralized water is added to meet the water content requirements of the liquid-liquid separator feed. The water separator agitator is then turned on and stirred evenly for a certain period. The reaction liquid in the water separator is then transferred to the liquid-liquid separator for oil-water separation. The aqueous phase obtained from centrifugation enters the wastewater tank for further processing, while the oil phase obtained from centrifugation enters the concentration tower for concentration.

[0122] In the fifth step, the concentration tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 60 to 75°C. The top vapor is condensed to 25 to 40°C by the top condenser and then enters the top reflux tank. After being pumped back to the top of the concentration tower by the top reflux pump, part of it is returned to the top of the concentration tower, and part is collected to the toluene bottom liquid in the polymerization reactor. The bottom temperature of the concentration tower is 70 to 85°C. The bottom liquid is pumped to the bottom heat exchanger of the concentration tower and cooled to 40 to 55°C before entering the modification reactor to continue the modification reaction.

[0123] Step 6: After transferring the concentrated solution to the modification reactor, add a certain amount of modified catalyst, turn on the reactor stirrer, and stir evenly. Set the reactor temperature to 45-60℃. When the material temperature inside the modification reactor reaches 45-60℃, add methacrylic anhydride dropwise to the reactor at a uniform rate to begin the modification reaction. Stir evenly for about 3 hours. After reaching the set time, raise the temperature to 65-85℃, maintain the temperature, and stir evenly for a certain period of time. After the reaction reaches the set time, turn on the second reaction circulation pump to cool the modified solution through external circulation cooling. After cooling, transfer the modified solution to the catalyst recovery tower.

[0124] Step 7: The catalyst recovery tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 55 to 65°C. The top vapor is condensed to 20 to 30°C by the catalyst recovery tower top condenser and then enters the catalyst recovery tower top reflux tank. After being pumped back to the top of the catalyst recovery tower by the catalyst recovery tower top reflux pump, part of it is returned to the top of the catalyst recovery tower; the rest is collected and recycled to the modification reactor. The bottom temperature of the catalyst recovery tower is 75 to 85°C. The bottom vapor is pumped to the bottom heat exchanger of the catalyst recovery tower and cooled to 45 to 55°C. Then it is mixed with a certain proportion of methanol and enters the first precipitation reactor to continue the precipitation operation.

[0125] Step 8: The modified liquid cooled by the heat exchanger at the bottom of the catalyst recovery tower is added dropwise to the first precipitation device along with a certain proportion of methanol. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into small-diameter particles. The temperature of the first precipitation device is maintained below 0-20℃ during the precipitation process, and the residence time of the precipitation process is less than 30 minutes. The precipitated slurry is then transported to the first filtration device for filtration and washing.

[0126] In the ninth step, after the feed is introduced into the first filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is coarsely dried with gas to form a wet filter cake. After the wet filter cake is unloaded, it enters the dissolving tank. The wet filter cake is added to the dissolving unit along with a certain proportion of hot toluene. Under stirring, the wet filter cake dissolves in the toluene. The dissolving process maintains a certain temperature in the dissolving tank, and the residence time is 30-60 minutes. The dissolved solution is then transported to the second precipitation unit for secondary precipitation.

[0127] Step 10: The dissolving liquid and a certain proportion of methanol are added dropwise into the second precipitation device. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into uniform small-diameter particles. The precipitation process maintains a certain temperature in the second precipitation vessel and the precipitation process residence time is 30~60 minutes. The precipitated slurry is then transported to the second filtration device for filtration and washing.

[0128] In the eleventh step, after the material is fed into the second filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is dried using gas, with the drying temperature controlled to not exceed 130~160℃. After drying, the volatile component content of the solid product is ≤0.6wt%. After the solid product cools to room temperature, it is unloaded, packaged, and weighed to obtain the modified polyphenylene ether product.

[0129] Example 2 Example 2 of this application provides a method for producing modified polyphenylene ether, applying... Figure 2 The production system for modified polyphenylene ether in Example 2 differs from Example 1 in that the post-processing unit adds a third stage of precipitation, filtration, and washing operations (i.e., the dissolution, precipitation, filtration, and washing processes are performed three times in total). This includes: The first step involves feeding 24 kg of toluene into a 50 L polymerization reactor. After feeding, the reactor agitator is activated. Then, 2.25 kg of 2,6-dimethylphenol and a catalyst containing cuprous oxide (di-n-butylamine) are added to the reactor. Simultaneously, nitrogen is introduced into the reactor, and the first reaction circulation pump is activated. The outlet temperature of the first circulation cooler is set to 10–50 °C. The polymerization process is exothermic, and heat is removed through an external cooling system. When the material temperature inside the reactor reaches 10–50 °C, oxygen is introduced, with nitrogen used as a balancing gas. An online oxygen analyzer is used to monitor and control the oxygen concentration in the outlet exhaust gas to ensure it does not exceed 10–15 v%. The polymerization reaction begins under thorough stirring and mixing. During the reaction, the reactor operates at a slightly positive pressure, at a temperature of 10–50 °C, and for a reaction time of 60–120 minutes. When the oxygen content in the reactor exceeds the set limit of 10–15 v%, the oxygen supply and concentrated solution feed are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system. Stop the agitator of the polymerization reactor and continue to supply nitrogen to prepare for the transfer of the reaction liquid to the coupling reactor.

[0130] The second step involves feeding 4 kg of toluene into the coupling reactor. After feeding, the reactor agitator is activated, and then 0.42 kg of bisphenol A coupling agent is added, while nitrogen is simultaneously introduced into the reactor. The polymerization process is exothermic, and the reaction temperature is maintained between 10 and 50°C through cooling via the external jacket of the coupling reactor. When the material temperature inside the coupling reactor drops below 10-50°C, the catalyst and the reaction liquid in the polymerization reactor are added, while oxygen is introduced. Nitrogen is used as a balancing gas, and the oxygen concentration in the outlet tail gas is monitored and controlled using an online oxygen analyzer to ensure it does not exceed 10-15 v%. The coupling polymerization reaction begins under thorough stirring and mixing. During the reaction, the pressure in the coupling reactor is 0.01-0.1 MPa(G), the operating temperature is 10-50°C, and the reaction time is 60-120 min. When the oxygen content in the coupling reactor exceeds the set limit of 10-15 v%, the oxygen supply and the feed of the reaction liquid are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system, and then stop the agitator of the coupling reactor.

[0131] Third, after transferring the reaction solution from the coupling reactor to the end-capping reactor, turn on the stirrer of the end-capping reactor, add the prepared chelating agent to the end-capping reactor, stir evenly, terminate the polymerization reaction, and maintain the temperature inside the end-capping reactor at approximately 20~50℃, stirring evenly for 10~30 minutes. After the set time is reached, raise the temperature of the end-capping reactor to 60~90℃, maintain the temperature, and stir evenly for 90~120 minutes. After the reaction reaches the set time, stop the stirrer of the end-capping reactor, stop heating, and allow the reaction solution in the end-capping reactor to flow by gravity into the water separator for further water separation and centrifugation.

[0132] The fourth step involves transferring the reaction liquid from the end-capped reactor to a water separator and allowing it to stand for a certain period to allow for oil-water separation. The bottom aqueous phase is then transferred to a wastewater tank, where a certain amount of demineralized water is added to meet the water content requirements of the liquid-liquid separator feed. The water separator agitator is then turned on and stirred evenly for a certain period. The reaction liquid in the water separator is then transferred to the liquid-liquid separator for oil-water separation. The aqueous phase obtained from centrifugation enters the wastewater tank for further processing, while the oil phase obtained from centrifugation enters the concentration tower for concentration.

[0133] In the fifth step, the concentration tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 60 to 75°C. The top vapor is condensed to 25 to 40°C by the top condenser and then enters the top reflux tank. After being pumped back to the top of the concentration tower by the top reflux pump, part of it is returned to the top of the concentration tower, and part is collected to the toluene bottom liquid in the polymerization reactor. The bottom temperature of the concentration tower is 70 to 85°C. The bottom liquid is pumped to the bottom heat exchanger of the concentration tower and cooled to 40 to 55°C before entering the modification reactor to continue the modification reaction.

[0134] Step 6: After transferring the concentrated solution to the modification reactor, add a certain amount of modified catalyst, turn on the reactor stirrer, and stir evenly. Set the reactor temperature to 45-60℃. When the material temperature inside the modification reactor reaches 45-60℃, add methacrylic anhydride dropwise to the reactor at a uniform rate to begin the modification reaction. Stir evenly for about 3 hours. After reaching the set time, raise the temperature to 65-85℃, maintain the temperature, and stir evenly for a certain period of time. After the reaction reaches the set time, turn on the second reaction circulation pump to cool the modified solution through external circulation cooling. After cooling, transfer the modified solution to the catalyst recovery tower.

[0135] Step 7: The catalyst recovery tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 55 to 65°C. The top vapor is condensed to 20 to 30°C by the catalyst recovery tower top condenser and then enters the catalyst recovery tower top reflux tank. After being pumped back to the top of the catalyst recovery tower by the catalyst recovery tower top reflux pump, part of it is returned to the top of the catalyst recovery tower; the rest is collected and recycled to the modification reactor. The bottom temperature of the catalyst recovery tower is 75 to 85°C. The bottom vapor is pumped to the bottom heat exchanger of the catalyst recovery tower and cooled to 45 to 55°C. Then it is mixed with a certain proportion of methanol and enters the first precipitation reactor to continue the precipitation operation.

[0136] Step 8: The modified liquid cooled by the heat exchanger at the bottom of the catalyst recovery tower is added dropwise to the first precipitation device along with a certain proportion of methanol. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into small-diameter particles. The temperature of the first precipitation device is maintained below 0-20℃ during the precipitation process, and the residence time of the precipitation process is less than 30 minutes. The precipitated slurry is then transported to the first filtration device for filtration and washing.

[0137] In the ninth step, after the feed is introduced into the first filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is coarsely dried with gas to form a wet filter cake. After the wet filter cake is unloaded, it enters the first dissolving unit. The wet filter cake is added to the first dissolving unit along with a certain proportion of hot toluene. Under stirring, the wet filter cake dissolves in the toluene. The dissolving process maintains a certain temperature within the first dissolving unit, with a residence time of 30-60 minutes. The dissolved solution is then transported to the second precipitation unit for secondary precipitation.

[0138] Step 10: The dissolving solution and a certain proportion of methanol are added dropwise into the second precipitation device. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into uniform small-diameter particles. The temperature of the second precipitation device is maintained below 0-20℃ during the precipitation process, and the residence time of the precipitation process is less than 30 minutes. The precipitated slurry is then transported to the second filtration device for filtration and washing.

[0139] In the eleventh step, after the feed is introduced into the second filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the solid filter cake layer. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is coarsely dried with gas to form a wet filter cake. After the wet filter cake is unloaded, it enters the second dissolving unit. The wet filter cake is added to the second dissolving unit along with a certain proportion of hot toluene. Under stirring, the wet filter cake dissolves in the toluene. The dissolving process maintains a certain temperature within the second dissolving unit, with a residence time of 30-60 minutes. The dissolved solution is then transported to the third precipitation unit for three precipitation processes.

[0140] In the twelfth step, the dissolving liquid and a certain proportion of methanol are added dropwise into the third precipitation device. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into uniform small-diameter particles. The temperature of the third precipitation device is maintained below 0-20℃ during the precipitation process, and the residence time of the precipitation process is less than 30 minutes. The precipitated slurry is then transported to the third filtration device for filtration and washing.

[0141] Step 13: After the feed is introduced into the third filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is dried using gas, with the drying temperature controlled to not exceed 130~160℃. After drying, the volatile component content of the solid product is ≤0.6wt%. After the solid product cools to room temperature, it is unloaded, packaged, and weighed to obtain the modified polyphenylene ether product.

[0142] Example 3 Example 3 of this application provides a method for producing modified polyphenylene ether, applying... Figure 3 The production system for modified polyphenylene ether, in Example 3, differs from Example 1 in that the first precipitation device uses two precipitation vessels connected in series. It includes: The first step involves feeding 24 kg of toluene into the polymerization reactor. After feeding, the reactor agitator is activated. Then, 2.25 kg of 2,6-dimethylphenol and a catalyst containing cuprous oxide (di-n-butylamine) are fed into the reactor. Simultaneously, nitrogen is introduced into the reactor, and the first reaction circulation pump is activated. The outlet temperature of the first circulation cooler is set to 10-50°C. The polymerization process is exothermic, and heat is removed through an external cooling system. When the material temperature inside the reactor reaches 10-50°C, oxygen is introduced, with nitrogen used as a balancing gas. An online oxygen analyzer is used to monitor and control the oxygen concentration in the outlet exhaust gas to ensure it does not exceed 10-15 v%. The polymerization reaction begins under thorough stirring and mixing. During the reaction, the reactor operates at a slightly positive pressure, at a temperature of 10-50°C, and for a reaction time of 60-120 minutes. When the oxygen content in the reactor exceeds the set limit of 10-15 v%, the oxygen supply and concentrated solution feed are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system. Stop the agitator of the polymerization reactor and continue to supply nitrogen to prepare for the transfer of the reaction liquid to the coupling reactor.

[0143] The second step involves feeding 4 kg of toluene into the coupling reactor. After feeding, the reactor agitator is activated, and then 0.42 kg of bisphenol A coupling agent is added, while nitrogen is simultaneously introduced into the reactor. The polymerization process is exothermic, and the reaction temperature is maintained between 10 and 50°C through cooling via the external jacket of the coupling reactor. When the material temperature inside the coupling reactor drops below 10-50°C, the catalyst and the reaction liquid in the polymerization reactor are added, while oxygen is introduced. Nitrogen is used as a balancing gas, and the oxygen concentration in the outlet tail gas is monitored and controlled using an online oxygen analyzer to ensure it does not exceed 10-15 v%. The coupling polymerization reaction begins under thorough stirring and mixing. During the reaction, the pressure in the coupling reactor is 0.01-0.1 MPa(G), the operating temperature is 10-50°C, and the reaction time is 60-120 min. When the oxygen content in the coupling reactor exceeds the set limit of 10-15 v%, the oxygen supply and the feed of the reaction liquid are immediately cut off, and a large amount of nitrogen is introduced for purging. Once the reaction reaches the set time, stop the oxygen supply and open the valve of the nitrogen purging oxygen pipeline to quickly replace the oxygen in the entire reaction system, and then stop the agitator of the coupling reactor.

[0144] Third, after transferring the reaction solution from the coupling reactor to the end-capping reactor, turn on the stirrer of the end-capping reactor, add the prepared chelating agent to the end-capping reactor, stir evenly, terminate the polymerization reaction, and maintain the temperature inside the end-capping reactor at approximately 20~50℃, stirring evenly for 10~30 minutes. After the set time is reached, raise the temperature of the end-capping reactor to 60~90℃, maintain the temperature, and stir evenly for 90~120 minutes. After the reaction reaches the set time, stop the stirrer of the end-capping reactor, stop heating, and allow the reaction solution in the end-capping reactor to flow by gravity into the water separator for further water separation and centrifugation.

[0145] The fourth step involves transferring the reaction liquid from the end-capped reactor to a water separator and allowing it to stand for a certain period to allow for oil-water separation. The bottom aqueous phase is then transferred to a wastewater tank, where a certain amount of demineralized water is added to meet the water content requirements of the liquid-liquid separator feed. The water separator agitator is then turned on and stirred evenly for a certain period. The reaction liquid in the water separator is then transferred to the liquid-liquid separator for oil-water separation. The aqueous phase obtained from centrifugation enters the wastewater tank for further processing, while the oil phase obtained from centrifugation enters the concentration tower for concentration.

[0146] In the fifth step, the concentration tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 60 to 75°C. The top vapor is condensed to 25 to 40°C by the top condenser and then enters the top reflux tank. After being pumped back to the top of the concentration tower by the top reflux pump, part of it is returned to the top of the concentration tower, and part is collected to the toluene bottom liquid in the polymerization reactor. The bottom temperature of the concentration tower is 70 to 85°C. The bottom liquid is pumped to the bottom heat exchanger of the concentration tower and cooled to 40 to 55°C before entering the modification reactor to continue the modification reaction.

[0147] Step 6: After transferring the concentrated solution to the modification reactor, add a certain amount of modified catalyst, turn on the reactor stirrer, and stir evenly. Set the reactor temperature to 45-60℃. When the material temperature inside the modification reactor reaches 45-60℃, add methacrylic anhydride dropwise to the reactor at a uniform rate to begin the modification reaction. Stir evenly for about 3 hours. After reaching the set time, raise the temperature to 65-85℃, maintain the temperature, and stir evenly for a certain period of time. After the reaction reaches the set time, turn on the second reaction circulation pump to cool the modified solution through external circulation cooling. After cooling, transfer the modified solution to the catalyst recovery tower.

[0148] Step 7: The catalyst recovery tower maintains a top pressure of -60 to -75 kPaG and a top temperature of 55 to 65°C. The top vapor is condensed to 20 to 30°C by the catalyst recovery tower top condenser and then enters the catalyst recovery tower top reflux tank. After being pumped back to the top of the catalyst recovery tower by the catalyst recovery tower top reflux pump, part of it is returned to the top of the catalyst recovery tower; the rest is collected and recycled to the modification reactor. The bottom temperature of the catalyst recovery tower is 75 to 85°C. The bottom vapor is pumped to the bottom heat exchanger of the catalyst recovery tower and cooled to 45 to 55°C. Then it is mixed with a certain proportion of methanol and enters the first precipitation reactor to continue the precipitation operation.

[0149] Step 8: The modified liquid, cooled by the heat exchanger at the bottom of the catalyst recovery tower, is added dropwise to the first precipitation device along with a certain proportion of methanol. This first precipitation device includes a first-stage precipitation vessel and a second-stage precipitation vessel connected in series. The modified liquid and methanol first enter the first-stage precipitation vessel. Under stirring, the large-diameter solid particles are broken down into smaller particles. The temperature of the first-stage precipitation vessel is maintained below 0-20°C, and the residence time is less than 30 minutes. The precipitated slurry formed in the first-stage precipitation vessel overflows into the second-stage precipitation vessel. The second-stage precipitation vessel receives the precipitated slurry from the first-stage vessel and continues to homogenize the particle size of the solid particles under stirring. The temperature of the second-stage precipitation vessel is maintained below 0-20°C, and the residence time is less than 30 minutes. The precipitated slurry is then transported to the first filtration device for filtration and washing.

[0150] In the ninth step, after the feed is introduced into the first filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is coarsely dried with gas to form a wet filter cake. After the wet filter cake is unloaded, it enters the dissolving unit. The wet filter cake is added to the dissolving unit along with a certain proportion of hot toluene. Under stirring, the wet filter cake dissolves in the toluene. The dissolving process maintains a certain temperature within the dissolving unit, with a residence time of 30-60 minutes. The dissolved solution is then transported to the second precipitation unit for secondary precipitation.

[0151] Step 10: The dissolving solution and a certain proportion of methanol are added dropwise into the second precipitation device. Under the action of stirring, the large-diameter solid particles that are precipitated are broken into uniform small-diameter particles. The temperature of the second precipitation device is maintained below 0-20℃ during the precipitation process, and the residence time of the precipitation process is less than 30 minutes. The precipitated slurry is then transported to the second filtration device for filtration and washing.

[0152] In the eleventh step, after the material is fed into the second filtration unit, filtration is performed first. The filtrate is then transported to the first collection unit. The filtered wet filter cake is washed with methanol to remove organic impurities from the surface of the solid filter cake. The washing solvent is then transported to the second collection unit. The washed and filtered wet slurry is dried using gas, with the drying temperature controlled to not exceed 130~160℃. After drying, the volatile component content of the solid product is ≤0.6wt%. After the solid product cools to room temperature, it is unloaded, packaged, and weighed to obtain the modified polyphenylene ether product.

[0153] Comparative Example 1 The specific operating steps differ from those in Example 1 in that a chelating agent is not added as a reaction terminator in step 3, while the other steps are the same.

[0154] Step three is as follows: After transferring the reaction solution from the coupling reactor to the end-capping reactor, turn on the stirrer of the end-capping reactor, heat the end-capping reactor to 60~90℃, maintain the temperature and stir evenly for 90~120 minutes. When the reaction reaches the set time, stop the stirrer of the end-capping reactor and stop heating. Let the reaction solution in the end-capping reactor flow by gravity into the water separator for further water separation and centrifugation.

[0155] In addition, the low molecular weight modified polyphenylene ethers obtained in Examples 1 to 3 and Comparative Example 1 of this application were subjected to product characteristic tests. The specific test methods are as follows: (1) Intrinsic viscosity test: 0.5g of the modified polyphenylene ether prepared in Example 1, Example 2 and Example 3 were respectively prepared into N,N-dimethylformamide (DMF) solution with a concentration of 0.5g / dL. Then, the intrinsic viscosity of the modified polyphenylene ether prepared in each example in DMF solution at 25℃ was measured by Ubbelohde viscometer. The results are shown in Table 1.

[0156] (2) Nitrogen content test: A certain amount of the modified polyphenylene ether prepared in Example 1, Example 2 and Example 3 were accurately weighed, dissolved in a certain proportion of toluene, and the nitrogen (N) content in the modified polyphenylene ether was measured and calculated using a chromatographic analyzer. The results are shown in Table 1.

[0157] (3) Test of copper residue: The residual amount of copper catalyst (Cu) in the modified polyphenylene ether prepared in Example 1, Example 2 and Example 3 was detected by flame atomic absorption spectrometry. The results are shown in Table 1.

[0158] (4) Residual hydroxyl content test: The modified polyphenylene ether prepared in Example 1, Example 2 and Example 3 were dissolved in pyridine solution, and tetrabutylammonium hydroxide isopropanol solution was used as titrant. The hydroxyl value was obtained by titration, and the residual hydroxyl content was calculated. The results are shown in Table 1.

[0159] (5) Molecular weight and molecular weight distribution test: The modified polyphenylene ethers prepared in Examples 1, 2 and 3 were dissolved in HPLC-grade tetrahydrofuran and characterized by gel permeation chromatography. The number-average molecular weight (Mn) and molecular weight distribution index (D) were determined. The results are shown in Table 1.

[0160] (6) Particle size test: The modified polyphenylene ether prepared in Example 1, Example 2 and Example 3 were analyzed by particle size analyzer and the particle size Dv (50) was determined. The results are shown in Table 1.

[0161] Table 1: Test Results of Modified Polyphenylene Ether Properties

[0162] As can be seen from the table above, the modified polyphenylene ethers prepared in Examples 1 to 3 of this application have intrinsic viscosities of 0.075~0.095 mL / g, exhibiting low viscosity and good processing fluidity. The residual copper catalyst content is ≤0.46ppm, with extremely low metal residue, meeting the high purity requirements of high-end electronic packaging materials; the residual hydroxyl content is <57ppm, indicating that the modification reaction is relatively complete and the product has good stability. The number average molecular weight is not greater than 2678 g / mol, the molecular weight distribution index is less than 1.78, and the molecular weight is controlled stably and uniformly. The particle size Dv(50) is 30.6~66.7μm, and products with different particle sizes can be obtained by adjusting the process. In contrast, Comparative Example 1, due to the absence of a chelating agent to terminate the reaction, has an intrinsic viscosity that increases to 0.124 mL / g, a significant increase in residual copper (1.09ppm) and residual hydroxyl content (347ppm), and a wider molecular weight distribution (D=1.95), indicating that the lack of termination and demetallization steps will seriously affect the purity and performance of the product. In summary, the modified polyphenylene ether prepared in this application has advantages such as low intrinsic viscosity, low metal residue, low residual hydroxyl content, narrow molecular weight distribution, and controllable particle size. The product has high purity, excellent processing performance and electrical properties, and is suitable for high-frequency copper clad laminates, 5G / 6G electronic packaging materials, and high-performance printed circuit boards.

[0163] The above description is merely a specific embodiment of this application. Obviously, various modifications and combinations can be made without departing from the spirit and scope of this application. Accordingly, this specification and accompanying drawings are merely exemplary illustrations of this application as defined by the appended claims, and are considered to cover any and all modifications, variations, combinations, or equivalents within the scope of this application. Clearly, those skilled in the art can make various alterations and modifications to this application without departing from the spirit and scope of this application. Thus, if these modifications and modifications of this application fall within the scope of the claims of this application and their equivalents, the intent of this application includes these modifications and modifications. Any changes or substitutions that can be easily conceived by those skilled in the art within the scope of the technology disclosed in this application should be included within the protection scope of this application. Therefore, the protection scope of this application should be determined by the protection scope of the claims.

Claims

1. A method for producing modified polyphenylene ether, characterized in that, include: 2,6-Dimethylphenol, organic solvent and polymerization catalyst are mixed and oxygen is introduced to carry out an oxidative polymerization reaction to obtain a first reaction solution containing monohydroxy polyphenyl ether. The first reaction solution is mixed with a coupling agent and a polymerization catalyst, and oxygen is introduced to carry out an oxidative coupling reaction to obtain a second reaction solution containing dihydroxy polyphenylene ether. The polymerization catalyst is a metal catalyst. The reaction was terminated by adding a terminator to the second reaction solution, and then dehydrated to obtain a dehydrated reaction solution. The dehydrated reaction solution is mixed with a modifier and a modifying catalyst to carry out a modification reaction, thereby obtaining a modified polymer solution. The modified polymer solution was post-treated to obtain modified polyphenylene ether.

2. The method for producing modified polyphenylene ether according to claim 1, characterized in that, The reaction temperature of the oxidative polymerization reaction is 10℃~50℃, the reaction pressure is 0.01MPa~0.1MPa, and the reaction time is 1 hour~2 hours; the reaction temperature of the oxidative coupling reaction is 10℃~50℃, the reaction pressure is 0.01MPa~0.1MPa, and the reaction time is 1 hour~2 hours.

3. The method for producing modified polyphenylene ether according to claim 1, characterized in that, The step of adding a terminator to the second reaction solution to terminate the reaction and then performing dehydration treatment to obtain a dehydrated reaction solution includes: Add a chelating agent to the second reaction solution and stir at 10℃~50℃ for 10min~30min. The reaction is terminated by the chelating agent combining with the metal ions contained in the metal catalyst, and the reaction solution after termination is obtained. The reaction solution after the termination reaction is heated to 60℃~90℃ and stirred for 90min~120min to remove some impurities in the reaction solution after the termination reaction, and the impurity-removed reaction solution is obtained. The aqueous phase in the purified reaction solution is separated to obtain the oil phase. Dehydrated water is added to the oil phase to remove residual metal ions from the polymerization catalyst, resulting in a dehydrated reaction solution.

4. The method for producing modified polyphenylene ether according to claim 1, characterized in that, The step of mixing the dehydrated reaction solution with a modifier and a modifying catalyst to carry out a modification reaction to obtain a modified polymer solution includes: The dehydrated reaction solution was mixed with the modified catalyst, heated to 45℃~60℃, and then a modifier was added. The mixture was reacted at 45℃~60℃ for 2.5 hours~3.5 hours to obtain the modified intermediate solution. The modified intermediate liquid is heated to 65℃~85℃ and kept at that temperature with stirring to obtain a modified polymer solution.

5. The method for producing modified polyphenylene ether according to claim 1, characterized in that, The modified polymer solution is post-treated to obtain modified polyphenylene ether, comprising: Under temperature conditions of 0℃~20℃, the modified polymer solution is mixed with a poor solvent, and the residence time is less than 30 minutes to precipitate and obtain a precipitated slurry. The poor solvent includes at least one of methanol, ethanol, and isopropanol. The precipitated slurry is filtered to obtain a filter cake and a filtrate, and the filter cake is washed with a poor solvent to obtain a washed filter cake. The washed filter cake is dissolved in an organic solvent to obtain a redissolved solution; Using the redissolved solution as a modified polymer solution, the precipitation, filtration, and washing operations were repeated at least once to obtain a purified filter cake. The purified filter cake was dried to obtain the modified polyphenylene ether.

6. The method for producing modified polyphenylene ether according to claim 1, characterized in that, Before mixing the dehydrated reaction solution with the modifier and the modifying catalyst for the modification reaction, the method further includes: The dehydrated reaction solution is concentrated under reduced pressure, and the organic solvent in the dehydrated reaction solution is recovered.

7. The method for producing modified polyphenylene ether according to claim 1, characterized in that, Before the modified polymer solution is mixed with a poor solvent to precipitate the product, the method further includes: The modified polymer solution is subjected to vacuum distillation to recover the modifier and modified catalyst from the modified polymer solution.

8. The method for producing modified polyphenylene ether according to claim 1, characterized in that, The method further includes: During the oxidative polymerization reaction and the oxidative coupling reaction, the volume concentration of oxygen in the reaction system is controlled to be less than or equal to 10%~15%; When the volume concentration of oxygen in the reaction system is greater than 10%~15%, the oxygen supply is cut off and nitrogen is introduced for replacement until the volume concentration of oxygen in the reaction system is less than or equal to 10%~15%.

9. The method for producing modified polyphenylene ether according to any one of claims 1 to 8, characterized in that, The polymerization catalyst includes a copper-based catalyst, the coupling agent includes a bisphenol compound, the terminator includes a chelating agent, the modifier includes methacrylic anhydride or an unsaturated acid anhydride, the modified catalyst includes an transesterification catalyst or a basic catalyst, and the organic solvent is selected from at least one of toluene, xylene, and benzene.

10. The method for producing modified polyphenylene ether according to any one of claims 1 to 8, characterized in that, The modified polyphenylene ether has a number-average molecular weight ≤3000g / mol, a molecular weight distribution index D<1.8, metal residue ≤0.5ppm, residual hydroxyl content <60ppm, and purity ≥99.9%.

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