A method of manufacturing polyphenylene ether particles
By controlling the size of polyphenylene ether (PPE) particles, the solvent composition during filtration and washing, and employing high-temperature nitrogen drying, the coking problem during the drying process of PPE particles was solved, thereby improving product quality and production efficiency.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- DALIAN ZHONGMU CHEM CO LTD
- Filing Date
- 2024-08-22
- Publication Date
- 2026-07-21
Abstract
Description
Technical Field
[0001] This invention relates to a method for manufacturing polyphenylene ether particles. Background Technology
[0002] Polyphenylene oxide (PPE) is a general-purpose engineering plastic. It has excellent dielectric properties, temperature resistance, and water resistance. Products made from it have high tensile strength and impact strength, and it is also self-extinguishing.
[0003] Polyphenylene ether (PPE) is typically produced by reacting xylenol with oxygen in an organic solvent using metal salts and amines as catalysts in an oxidative coupling reaction. The reaction mixture is then subjected to precipitation, filtration, washing, and drying to obtain PPE powder, as described in patents US20170275434, CN107236124A, CN104136490B, CN103154086B, and CN103421181A.
[0004] In fact, during the drying process of large-scale production, the presence of solvent in the polyphenylene ether particles can easily cause the particles to melt, coke, and stick together when the solvent is removed by heating. This leads to scaling in the dryer and coking in the product, which seriously affects product quality. Patent CN111978535B discloses a method for manufacturing polyphenylene ether to reduce scaling in the dryer. However, this method requires setting up dryers in series, which is complex in terms of equipment and operation, has high costs, and the actual effect is not ideal.
[0005] Therefore, a method for manufacturing polyphenylene ether (PPE) particles is needed to further reduce the possibility of coking during the drying process of PPE particles. Summary of the Invention
[0006] The problem that the invention aims to solve As stated above, the risk of coking and sticking still exists when drying polyphenylene ether using the techniques disclosed to date.
[0007] Therefore, the object of the present invention is to provide a method for reducing coking problems during the drying process of polyphenylene ether particles.
[0008] Methods for solving problems The inventors conducted in-depth research on the above problems and found that by controlling the particle size during the precipitation of polyphenylene ether, controlling the solvent composition during filtration and washing, controlling the drying temperature during drying, and using nitrogen as a heat source, coking during the drying process can be effectively avoided.
[0009] The present invention is as follows: [1] During the polymerization and precipitation process, the polyphenylene ether precipitate particles are controlled to a suitable size by the ratio of good solvent to bad solvent, with an average particle size greater than 120 micrometers. [2] During the filtration and washing process, the polyphenylene ether particles are filtered and washed with an aqueous washing solution. The washing solution consists of alcohol compounds and a washing accelerator. The washing accelerator contains water and dimethylamine. The alcohol compounds account for 88-94.4%, the water content is 5-10%, and the dimethylamine content is 0.1-2%. After filtration and washing, the moisture content of the polyphenylene ether particles is controlled to be less than 50%. [3] The drying process is carried out by a rotary drum dryer. High-temperature nitrogen is used as the heat source. High-temperature nitrogen is introduced from the material discharge end of the rotary drum dryer and carries organic vapor from the material inlet end. During the rotation of the dryer drum, the polyphenylene ether particles are continuously introduced from one end of the dryer and continuously discharged from the other end. [4] The weight-average molecular weight of polyphenylene ether is greater than 15,000.
[0010] The effects of the invention 1. The method for preparing polyphenylene ether particles provided by the present invention can effectively avoid coking during the drying process and obtain high-quality polyphenylene ether powder.
[0011] 2. The method for preparing polyphenylene ether particles provided by the present invention achieves an average particle size of 120 micrometers, which can effectively reduce the degree of polyphenylene ether powder flying in the dryer, avoid pipeline blockage, and improve yield. Detailed Implementation
[0012] The following is a detailed description of the method for implementing the present invention (hereinafter referred to as "this embodiment"). This embodiment is an example used to illustrate the present invention; the present invention is not limited to this embodiment, and can be implemented with appropriate modifications within the scope of its key points.
[0013] [Polyphenylene ether polymerization] The polyphenylene ether of this embodiment has a weight-average molecular weight greater than 15,000 (determined by sol-gel chromatography). It is obtained by polymerizing xylenol monomer in an organic solvent, with copper salt-amine as the catalyst. Xylenol undergoes an oxidative coupling reaction with oxygen, and the reaction solution is treated with an organic acid as a terminator after the reaction.
[0014] Organic solvents, phenolic monomers, copper salts, and amines are added to a stirred reactor in a certain proportion. After adjusting to the set temperature, oxygen is introduced from the bottom of the reactor under stirring conditions, and polymerization occurs. The temperature of the material in the reactor is maintained within a certain range. After the reaction endpoint is reached, the oxygen is stopped to terminate the reaction. A certain amount of organic acid is added, and the polymerization ends, resulting in a mixed solution containing polyphenylene ether.
[0015] Xylenol refers to one or more of 2,6-dimethylphenol, 2,6-diethylphenol, and 2,5-dimethylphenol.
[0016] Organic solvents refer to good solvents for polyphenylene ethers, including small molecule compounds containing benzene rings, such as benzene, toluene, chlorobenzene, xylene, and trimethylbenzene, with toluene, chlorobenzene, and xylene being preferred.
[0017] The copper salt in this embodiment refers to one or more of the following: copper chloride, cuprous chloride, copper bromide, copper nitrate, copper sulfate, etc.
[0018] Amines are organic compounds containing nitrogen and carbon elements, such as triethylamine, trimethylamine, tributylamine, aniline, cyclohexylamine, ethylenediamine, morpholine, p-phenylenediamine, dibutylamine, diethylamine, etc., or a mixture of one or more of them.
[0019] The oxygen used in this embodiment is oxygen with a purity greater than 95%, preferably greater than 97%.
[0020] Organic acids used to terminate reactions are compounds containing carboxyl groups, such as acetic acid, benzoic acid, EDTA, and sodium salts of EDTA.
[0021] [Precipitation and Sedimentation] In this embodiment, the polyphenylene ether reaction solution undergoes a precipitation process upon contact and mixing with a poor solvent. The size of the precipitated particles is controlled by the amount of poor solvent added, with a preferred mass content of 40-50%. The resulting particles have an average diameter greater than 120 micrometers. The good solvent is an aromatic solvent such as xylene, chlorobenzene, or toluene; the poor solvent is an alcohol solvent such as methanol, propylene glycol, ethanol, or butanol.
[0022] [Filtering and washing] The filtration and washing process of polyphenylene ether (PPE) particles in this embodiment first involves filtering the PPE particles using a filter to achieve liquid-solid separation. To further remove residual impurities from the particles, the PPE filter cake needs to be washed with a washing solution. The washing solution comprises alcohol compounds and a washing accelerator. The alcohol compounds include methanol, ethanol, propanol, butanol, etc., with methanol being preferred. The washing accelerator comprises water and dimethylamine. Dimethylamine refers to a dimethylamine compound with a structure such as (CH3)2NX, where X is C. 1-10 Alkyl substituents. Washing solution composition: 88-94.4% alcohols, 5-10% water, 0.1-2% dimethylamine. The moisture content of the filter cake after filtration is less than 50%.
[0023] [dry] In this embodiment, drying is performed using a rotary drum dryer. High-temperature nitrogen gas is used as the heat source, introduced from the material discharge end of the dryer and carrying organic vapors out from the material inlet end. During the rotation of the dryer drum, polyphenylene ether (PPE) particles are continuously introduced from one end and continuously discharged from the other. The rotation of the drum facilitates the transport of PPE particles and heat exchange with the hot nitrogen gas. The initial temperature T during the introduction of hot nitrogen gas is... in The outlet nitrogen temperature is 140-160℃, after heat exchange with polyphenylene ether particles to evaporate the solvent. out For T r +20℃ to T r +40℃, where T r The boiling point of the main component of the washing solution (methanol boiling point 64.5℃). The outlet nitrogen temperature is controlled within a suitable range by the amount of hot nitrogen introduced. The outlet nitrogen temperature should not be too high or too low. If the outlet nitrogen temperature is too high, coking is likely to occur and energy consumption will be high. If the outlet nitrogen temperature is too low, the polyphenylene ether will not dry sufficiently. The standard value for sufficient drying is set at a solvent content of less than or equal to 0.4%.
[0024] The method for manufacturing polyphenylene ether particles of the present invention is not limited to the method for manufacturing polyphenylene ether particles of this embodiment described above. Appropriate adjustments can be made to the specific order, number of operations, washing solution composition, drying section temperature, dryer type and structure, etc. in the polymerization process and post-treatment process described above. Example
[0025] The following specific embodiments and comparative examples illustrate this implementation method in detail, but this implementation method is not limited to the following embodiments.
[0026] [polymerization] Example
[0027] In a 3L double-walled glass reactor, 1300g of toluene, 12g of aniline, 2g of diethylamine, and 0.23g of copper chloride were added and stirred until dissolved. Then, 200g of 2,6-dimethylphenol was added, and the material temperature was adjusted to 30℃. Under stirring, oxygen (98.5% purity) was introduced from the bottom of the reactor at a rate of 200mL / min to initiate polymerization. The material temperature was controlled between 40-43℃ using the reactor jacket. After 60 minutes of polymerization, the oxygen was stopped, and the polymerization was completed. 1.6g of EDTA-2Na was then added to the reactor to obtain a mixed solution of polyphenylene ether.
[0028] The mixed solution was mixed with 300g of distilled water, allowed to stand and separate into layers, and the water layer was removed to obtain polyphenylene ether solution P1. The weight-average molecular weight obtained from sampling and testing was 18500. Example
[0029] In a 3L double-walled glass reactor, 1300g toluene, 12g aniline, 2g diethylamine, and 0.33g copper chloride were added and stirred until dissolved. Then, 200g 2,6-dimethylphenol was added, and the material temperature was adjusted to 30℃. Under stirring, oxygen (98.5% purity) was introduced from the bottom of the reactor at a rate of 200mL / min to initiate polymerization. The material temperature was controlled between 40-43℃ using the reactor jacket. After 60 minutes of polymerization, the oxygen was stopped, and the polymerization was completed. 2g EDTA-2Na was then added to the reactor to obtain a mixed solution of polyphenylene ether.
[0030] The mixed solution was mixed with 300g of distilled water, allowed to stand and separate into layers, and the water layer was removed to obtain polyphenylene ether solution P2. The weight-average molecular weight obtained from sampling and testing was 29000. Example
[0031] In a 3L double-walled glass reactor, 1300g toluene, 12g aniline, 2g diethylamine, and 0.43g copper chloride were added and stirred until dissolved. Then, 200g 2,6-dimethylphenol was added, and the material temperature was adjusted to 30℃. Under stirring, oxygen (98.5% purity) was introduced from the bottom of the reactor at a rate of 200mL / min to initiate polymerization. The material temperature was controlled between 40-43℃ using the reactor jacket. After 60 minutes of polymerization, the oxygen was stopped, and the polymerization was completed. 2g EDTA-2Na was then added to the reactor to obtain a mixed solution of polyphenylene ether.
[0032] The mixed solution was mixed with 300g of distilled water, allowed to stand and separate into layers, and the water layer was removed to obtain polyphenylene ether solution P3. The weight-average molecular weight obtained from sampling and testing was 48,000.
[0033] Comparative Example S1 In a 3L double-walled glass reactor, 1300g of toluene, 12g of aniline, 2g of diethylamine, and 0.13g of copper chloride were added and stirred until dissolved. Then, 200g of 2,6-dimethylphenol was added, and the material temperature was adjusted to 30℃. Under stirring, oxygen (98.5% purity) was introduced from the bottom of the reactor at a rate of 200mL / min to initiate polymerization. The material temperature was controlled between 40-43℃ using the reactor jacket. After 60 minutes of polymerization, the oxygen was stopped, and the polymerization was completed. 2g of EDTA-2Na was then added to the reactor to obtain a mixed solution of polyphenylene ether.
[0034] The mixed solution was mixed with 300g of distilled water, allowed to stand and separate into layers, and the water layer was removed to obtain a polyphenylene ether solution. The weight-average molecular weight obtained from sampling and testing was 13000. [Precipitation] Example
[0035] The polyphenylene ether solution P1 obtained in Example 1 was mixed with 1000g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 137 micrometers. Example
[0036] The polyphenylene ether solution P1 obtained in Example 1 was mixed with 1200g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 128 micrometers. Example
[0037] The polyphenylene ether solution P2 obtained in Example 2 was mixed with 1000g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 139 micrometers. Example
[0038] The polyphenylene ether solution P2 obtained in Example 2 was mixed with 1200g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 125 micrometers. Example
[0039] The polyphenylene ether solution P3 obtained in Example 3 was mixed with 1300g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 142 micrometers. Example
[0040] The polyphenylene ether solution P3 obtained in Example 3 was mixed with 1100g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After sampling and drying, the average diameter of the particles was measured to be 124 micrometers.
[0041] Comparative Example Y1 The polyphenylene ether solution P3 obtained in Example 3 was mixed with 3300g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 77 micrometers.
[0042] Comparative Example Y2 The polyphenylene ether solution obtained in Comparative Example S1 was mixed with 1000g of methanol and stirred at high speed for 10 minutes to obtain a slurry containing polyphenylene ether particles. After drying, the average diameter of the particles was measured to be 93 micrometers. [Filtering and washing] Example
[0043] The polyphenylene ether granular slurry obtained in Example 4 was filtered, and the polyphenylene ether filter cake was washed with methanol washing solution. The methanol washing solution composition was: methanol 91.4%, water 8.2%, and trimethylamine 0.4%. The moisture content of the filter cake was 48%. Example
[0044] The polyphenylene ether granular slurry obtained in Example 5 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 92% methanol, 7.5% water, and 0.5% trimethylamine. The moisture content of the filter cake was 48%. Example
[0045] The polyphenylene ether granular slurry obtained in Example 6 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 90.7% methanol, 9% water, and 0.3% dimethyl butylamine. The moisture content of the filter cake was 47%. Example
[0046] The polyphenylene ether granular slurry obtained in Example 7 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 93.8% methanol, 6% water, and 0.6% trimethylamine. The moisture content of the filter cake was 46%. Example
[0047] The polyphenylene ether granular slurry obtained in Example 8 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 94.1% methanol, 5.5% water, and 0.4% trimethylamine. The moisture content of the filter cake was 47%. Example
[0048] The polyphenylene ether granular slurry obtained in Example 9 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 91.4% methanol, 8.2% water, and 0.4% dimethyl butylamine. The moisture content of the filter cake was 47%.
[0049] Comparative Example Z1 The polyphenylene ether granular slurry obtained in Example 9 was filtered, and the polyphenylene ether filter cake was washed with methanol washing solution. The methanol washing solution composition was: methanol 91.8% and water 8.2%. The moisture content of the filter cake was 48%.
[0050] Comparative Example Z2 The polyphenylene ether granular slurry obtained in Example 9 was filtered, and the polyphenylene ether filter cake was washed with a methanol washing solution. The methanol washing solution consisted of 99% methanol, 0.5% water, and 0.5% trimethylamine. The moisture content of the filter cake was 52%.
[0051] Comparative Example Z3 The polyphenylene ether granular slurry obtained in Comparative Example Y1 was filtered, and the polyphenylene ether filter cake was washed with methanol washing solution. The methanol washing solution composition was: methanol 91.4%, water 8.2%, and dimethyl butylamine 0.4%. The moisture content of the filter cake was 47%. [dry] Example
[0052] The wet polyphenylene ether granules obtained in Example 10 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 145°C, a nitrogen discharge temperature of 86°C, and an introduction rate of 12 L / min.
[0053] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%. Example
[0054] The wet polyphenylene ether granules obtained in Example 11 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 145°C, a nitrogen discharge temperature of 91°C, and an introduction rate of 14 L / min.
[0055] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%. Example
[0056] The wet polyphenylene ether granules obtained in Example 12 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 95°C, and an introduction rate of 12 L / min.
[0057] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%. Example
[0058] The wet polyphenylene ether granules obtained in Example 13 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 90°C, and an introduction rate of 10 L / min.
[0059] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%. Example
[0060] The wet polyphenylene ether granules obtained in Example 14 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 160°C, a nitrogen discharge temperature of 97°C, and an introduction rate of 10 L / min.
[0061] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%. Example
[0062] The wet polyphenylene ether granules obtained in Example 15 were dried using a small rotary drum dryer with a rotation speed of 13 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 97°C, and an introduction rate of 10 L / min.
[0063] Results: The polyphenylene ether particles did not stick together or coke in the dryer, and the solvent residue in the polyphenylene ether particles after drying was less than 0.4%.
[0064] Comparative Example Q1 The wet polyphenylene ether granules obtained in Example 15 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 130°C, a nitrogen discharge temperature of 82°C, and an introduction rate of 10 L / min.
[0065] Results: The polyphenylene ether particles in the dryer were found to be sticking together, and the solvent residue in the polyphenylene ether particles was greater than 0.9%, which did not meet the standard. The standard value is a solvent residue of less than or equal to 0.4%.
[0066] Comparative Example Q2 The wet polyphenylene ether granules obtained in Example 15 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 170°C, a nitrogen discharge temperature of 108°C, and an introduction rate of 10 L / min.
[0067] Result: Large areas of coking occurred in the polyphenylene ether particles in the dryer, making it impossible to smoothly remove the polyphenylene ether particles.
[0068] Comparative Example Q3 The wet polyphenylene ether granules obtained in Comparative Example Z1 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 89°C, and an introduction rate of 10 L / min.
[0069] Results: Polyphenylene ether particles in the dryer showed signs of sticking together and adhering to the inner wall of the dryer, with some areas showing signs of coking.
[0070] Comparative Example Q4 The wet polyphenylene ether granules obtained in Comparative Example Z2 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 89°C, and an introduction rate of 10 L / min.
[0071] Results: Polyphenylene ether particles in the dryer showed signs of sticking together and adhering to the inner wall of the dryer.
[0072] Comparative Example Q5 The wet polyphenylene ether granules obtained in Comparative Example Z3 were dried using a small rotary drum dryer with a rotation speed of 10 r / min, an initial temperature of hot nitrogen of 155°C, a nitrogen discharge temperature of 89°C, and an introduction rate of 10 L / min.
[0073] Results: Polyphenylene ether particles in the dryer showed signs of sticking together and adhering to the inner wall of the dryer. During the process, polyphenylene ether powder was scattered.
Claims
1. A method for manufacturing polyphenylene ether particles, characterized by: a) In the polymerization and precipitation process, xylenol is used as a monomer. In the presence of a catalyst, it undergoes an oxidative coupling reaction with oxygen in an organic solvent to obtain a polyphenylene ether mixture. The mixture is then mixed with a poor solvent to precipitate the polyphenylene ether particles. The ratio of good solvent to poor solvent is used to control the size of the precipitated polyphenylene ether particles to a suitable size. b) Filtration and washing process: During the filtration and washing process of polyphenylene ether particles, the washing solution contains undesirable solvents and washing accelerators; control the moisture content of the filter cake after filtration and washing. c) The drying process uses a rotary drum dryer with high-temperature nitrogen as the heat source; In this process, methanol is used as the undesirable solvent during precipitation, with a methanol content of 40-50% by mass. The average particle size of the polyphenylene ether precipitates is greater than 120 micrometers, and the weight-average molecular weight of the polyphenylene ether is greater than 15,000. The washing accelerators include water and dimethylamine, with a water content of 5-10% and a dimethylamine content of 0.1-2%. The moisture content of the filter cake after filtration and washing is less than 50%. During the drying process, high-temperature nitrogen gas is introduced from the material discharge end of the rotary drum dryer and carries organic vapors out from the material inlet end. The initial temperature T when the high-temperature nitrogen gas is introduced into the dryer is set at... in The outlet nitrogen temperature is 140-160℃, after heat exchange with polyphenylene ether particles to evaporate the solvent. out For T r +20℃ to T r +40℃, where T r It is the boiling point of the main component of the washing solution.
2. The method for manufacturing polyphenylene ether particles according to claim 1, characterized in that, The good solvent is xylene, chlorobenzene, or toluene.