Metal ion impurity removal method in polymer production and application

Abstract

The invention belongs to the technical field of chemical product preparation, and particularly relates to a metal ion impurity removal method in polymer production and application. The invention provides a metal ion impurity removal method in polymer production. The metal ion impurity removal method comprises the steps of precipitation, filtration, water washing and centrifugation. The invention also provides an application of the impurity removal method in polyphenyl ether impurity removal. In the technical scheme provided by the invention, after the polymer solution to be subjected to impurity removal is mixed with the precipitant, mixed impurity metal ions are precipitated and separated out, then the impurity-removed pure product is obtained through further filtration, water washing and centrifugation, the impurity metal ions do not react with polyphenyl ether in the impurity removal process, the stability of the polyphenyl ether structure is ensured, and the purity of the polyphenyl ether is improved. The generated metal ion precipitate is stable in structure and not easy to decompose; through determination, the copper content in the polyphenyl ether after impurity removal is less than 2.0 mg / kg (or 2ppm), and the technical defect of poor copper removal stability of a method for removing copper ions in the polyphenyl ether by using a chelating agent in the prior art is overcome.

Description

Technical Field

[0001] The present application belongs to the technical field of chemical product preparation, and in particular relates to a method and application of removing metal ions in polymer production. Background Art

[0002] Polyphenylene ether resin is one of the five major engineering plastics. It has the advantages of low dielectric constant, low loss factor, high glass transition temperature, flame retardancy, dimensional stability, etc. It is widely used in electronic appliances, automobile industry, household appliances, industrial machinery and other industries. The production process of polyphenylene ether includes: solvent-free melting method, homogeneous solution polycondensation method, precipitation polycondensation method, all-water medium method, etc. The industrially produced polyphenylene ether mostly uses 2,6-dimethylphenol as raw material. Under the action of copper-amine complex catalyst, it polymerizes with oxygen in oxygen-containing gas to generate polyphenylene ether products. The residual copper ions in polyphenylene ether products are inevitable. Copper content is one of the main indicators of product performance. According to the national standard "Plastic Polyphenylene Ether (PPE) Resin" (GB / T41874-2022), the copper content of qualified products should not exceed 10.0 mg / kg, and the copper content of superior products should not exceed 3.0 mg / kg.

[0003] In the prior art, the method for removing copper from polyphenylene ether products is mostly to add chelating agents such as ethylenediaminetetraacetic acid and its salts to the polymer solution. However, this method has poor copper removal stability and it is difficult to obtain a polyphenylene ether product that meets the standards.

[0004] Therefore, a method and application of metal ion removal in polymer production is developed to solve the technical defect of poor copper removal stability in the prior art method of using chelating agents to remove copper ions in polyphenylene ether, which has become an urgent problem to be solved by technicians in this field. Summary of the invention

[0005] Based on this, it is necessary to provide a method and application of metal ion removal in polymer production in view of the technical defect that the method of using a chelating agent to remove copper ions in polyphenylene ether has poor copper removal stability.

[0006] In order to more clearly illustrate the metal ion impurity removal method in polymer production provided by the present application, the impurity removal device used in the impurity removal method is first described below.

[0007] A metal ion impurity removal device used in the present application includes: a precipitation kettle, a filter, a water washing kettle and a centrifuge; the liquid phase discharge end of the precipitation kettle is connected to the filter, the liquid phase discharge end of the filter is connected to the water washing kettle, and the liquid phase discharge end of the water washing kettle is connected to the centrifuge.

[0008] In one embodiment, the impurity removal device further includes: a sedimentation tank, and the sedimentation tank is arranged between the precipitation tank and the filter.

[0009] In one embodiment, the impurity removal device further includes: a first pump, wherein the first pump is disposed between the liquid phase discharge end of the filter and the water washing kettle.

[0010] In one embodiment, the impurity removal device further includes: a second pump, which is arranged between the liquid phase discharge end of the water washing kettle and the centrifuge.

[0011] In one embodiment, a stirring part is provided in the precipitation kettle;

[0012] and / or,

[0013] A stirring part is provided in the water washing kettle.

[0014] In one embodiment, the impurity removal device further includes: a third pump, and the third pump is arranged between the precipitation tank and the precipitation kettle.

[0015] In one of the embodiments, the impurity removal device further comprises: a post-processing unit, the post-processing unit being connected to the liquid phase discharge end of the centrifuge;

[0016] The post-processing unit includes any one or more of a concentration section, a washing section and a drying section.

[0017] In one of the embodiments, a water washing liquid feed port is provided in the water washing kettle.

[0018] In one embodiment, the particle size of the filter is 20-400 mesh.

[0019] In one embodiment, the particle size of the filter is 50-200 mesh.

[0020] In one embodiment, the centrifuge is a liquid-liquid two-phase centrifuge or a solid-liquid-liquid three-phase centrifuge.

[0021] The present application provides a method for removing metal ions from polymer production, the method comprising:

[0022] Step 1, precipitation: the polymer solution to be decontaminated is mixed with a precipitant, and the liquid phase product is collected after precipitation to obtain a first product;

[0023] Step 2, filtration: filtering the first product to collect the liquid phase product to obtain the second product;

[0024] Step 3, washing with water: washing the second product with water to collect the liquid phase product to obtain the third product;

[0025] Step 4, centrifugation: the third product is centrifuged to obtain a decontaminated product.

[0026] In one embodiment, in step one, the precipitant includes: alkali solution and / or carbonate aqueous solution.

[0027] In one embodiment, in step 1, the alkali solution is a strong alkali aqueous solution, and the concentration of hydroxide ions in the alkali solution is 0.25-2.5 mol / L.

[0028] In one embodiment, in step 1, the alkali solution is a strong alkali aqueous solution, and the concentration of hydroxide ions in the alkali solution is 1-2 mol / L.

[0029] In one embodiment, in step 1, the carbonate aqueous solution is: sodium carbonate and / or sodium bicarbonate.

[0030] In one embodiment, in step 1, the concentration of bicarbonate ions in the carbonate aqueous solution is 0.25-2.5 mol / L;

[0031] and / or,

[0032] The carbonate ion concentration in the carbonate aqueous solution is 0.125-1.25 mol / L.

[0033] In one embodiment, in step 1, the concentration of bicarbonate ions in the carbonate aqueous solution is 1-2 mol / L;

[0034] and / or,

[0035] The carbonate ion concentration in the carbonate aqueous solution is 0.5-1.0 mol / L.

[0036] In one embodiment, in step 1, the amount of the precipitant added is 1.5 wt% to 5.0 wt% of the polymer solution to be decontaminated.

[0037] In one embodiment, in step 1, the amount of the precipitant added is 2.0-4.0 wt % of the polymer solution to be decontaminated.

[0038] In one embodiment, the impurity removal method further includes post-processing, wherein the impurity-removed product is concentrated, washed and dried in sequence to obtain a post-processed impurity-removed product.

[0039] The present application also provides an application of any of the above impurity removal methods in the impurity removal of polyphenylene ether.

[0040] In one embodiment, the application is to remove metal ions from polyphenylene ether.

[0041] In one embodiment, the application is to remove copper ions from polyphenylene ether.

[0042] In one embodiment, the residual copper ion content of the polyphenylene ether product is less than 2.0 mg / kg.

[0043] In summary, the present application provides a method for removing metal ions from polymer production, including: precipitation, filtration, water washing and centrifugation. The present application also provides an application of the above-mentioned impurity removal method in the removal of polyphenylene ether. In the technical scheme provided by the present application, after the impurity-removing polymer solution is mixed with a precipitant, the mixed impurity metal ions are precipitated and precipitated, and then further filtered, washed and centrifuged to obtain a pure product after impurity removal. During the impurity removal process, the polyphenylene ether does not react, thereby ensuring the stability of the polyphenylene ether structure, and the generated metal ion precipitation structure is stable and not easy to decompose; it has been determined that the copper content in the polyphenylene ether after impurity removal is less than 2.0 mg / kg (or 2 ppm), which is lower than the copper content of less than 3 ppm required for commercially available high-quality polyphenylene ether products. Through the technical means of simple chemical precipitation coupled with physical separation, the technical defect of poor copper removal stability in the prior art of using a chelating agent to remove copper ions in polyphenylene ether is solved. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] In order to more clearly illustrate the embodiments of the present application or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present application. For ordinary technicians in this field, other drawings can be obtained based on the provided drawings without paying any creative work.

[0045] Figure 1 A schematic diagram of the structure of an impurity removal device used in a metal ion impurity removal method in polymer production provided in an embodiment of the present application;

[0046] Figure 2 A schematic diagram of a process for removing metal ions from polymer production in the technical solution provided in the embodiment of the present application;

[0047] Among them, there are a precipitation tank R1, a stirring part M, a precipitation tank V1, a filter F1, a first pump B1, a water washing tank V2, a second pump B2 and a centrifuge M1. DETAILED DESCRIPTION

[0048] The embodiments of the present application provide a method for removing metal ions in polymer production, which is used to solve the technical defect of the prior art method of using a chelating agent to remove copper ions in polyphenylene ether, that is, the copper removal stability is poor.

[0049] In order to make the above-mentioned purposes, features and advantages of the present application more obvious and easy to understand, the specific implementation methods of the present application are described in detail below in conjunction with the accompanying drawings. In the following description, many specific details are set forth to facilitate a full understanding of the present application. However, the present application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar improvements without violating the connotation of the present application, so the present application is not limited by the specific embodiments disclosed below.

[0050] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", "axial", "radial", "circumferential" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the referred device or element must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as a limitation on the present application.

[0051] In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include at least one of the features. In the description of this application, the meaning of "plurality" is at least two, such as two, three, etc., unless otherwise clearly and specifically defined.

[0052] In this application, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements, unless otherwise clearly defined. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0053] In the present application, unless otherwise clearly specified and limited, a first feature being “above” or “below” a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being “above”, “above”, and “above” a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being “below”, “below”, and “below” a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0054] It should be noted that when an element is referred to as being "fixed to" or "disposed on" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "upper", "lower", "left", "right" and similar expressions used herein are for illustrative purposes only and are not intended to be the only implementation method.

[0055] In order to more clearly illustrate the metal ion impurity removal method in polymer production provided by the present application, the metal ion impurity removal device used in the impurity removal method is first described below.

[0056] See also Figure 1 In the metal ion impurity removal method in polymer production of the embodiment of the present application, the metal ion impurity removal device used includes: a precipitation kettle, a filter, a water washing kettle and a centrifuge; the liquid phase discharge end of the precipitation kettle is connected to the filter, the liquid phase discharge end of the filter is connected to the water washing kettle, and the liquid phase discharge end of the water washing kettle is connected to the centrifuge. The embodiment of the present application provides a metal ion impurity removal device, which solves the technical defect of the method of using a chelating agent to remove copper ions in polyphenylene ether in the prior art, which has poor copper removal stability.

[0057] In order to more clearly explain the metal ion impurity removal device provided in the embodiment of the present application, the raw material to be impurity-removed here is a polyphenylene ether product containing copper ions. However, it should be emphasized that this does not constitute a limitation on the protection scope of the present application, and the metal ion impurity removal device provided in the present application can also be used to remove metal ions mixed in other organic substances.

[0058] In the technical solution provided in the embodiment of the present application, the polyphenylene ether containing copper ions is precipitated in a precipitation kettle. Here, the copper ions can be precipitated by adding a precipitant, such as a precipitant containing hydroxide ions or carbonate ions, and the precipitant is fully stirred with the polyphenylene ether containing copper ions to precipitate. The copper ions are precipitated in the form of copper hydroxide or copper carbonate. The specific principle is:

[0059] Cu 2+ +2OH - →Cu(OH) 2↓

[0060] 2Cu 2+ +CO3 2- +2OH - →Cu2(OH)2CO 3↓

[0061] The remaining liquid polyphenylene ether product is filtered through a filter to remove the uncompleted precipitate, and the water washing kettle is further used to wash away the precipitated impurities of the liquid polyphenylene ether product. The liquid polyphenylene ether is then centrifuged to remove the unwashed solids to obtain the impurity-free polyphenylene ether product.

[0062] To further optimize the technical solution, the impurity removal device in the present application further includes: a precipitation tank, which is arranged between the precipitation kettle and the filter. After the copper ions in the precipitation kettle undergo precipitation reaction, the copper-containing precipitate can be completely precipitated by standing in the precipitation tank, thereby further optimizing the impurity removal effect.

[0063] Between the connecting structure of the filter and the water washing kettle, the liquid phase polyphenylene ether flowing out of the liquid phase discharge end can flow from the filter to the water washing kettle by the action of gravity. In the actual impurity removal operation, in order to effectively improve the impurity removal efficiency, the impurity removal device in the present application also includes: a first pump, and the first pump is arranged between the liquid phase discharge end of the filter and the water washing kettle. Through the action of the first pump, the liquid phase polyphenylene ether to be impurity-removed can be uniformly and continuously pumped into the water washing kettle from the filter to improve the working efficiency of the impurity removal device.

[0064] Similarly, a decontamination device in the present application further includes: a second pump, which is arranged between the liquid phase discharge end of the water washing kettle and the centrifuge. Through the action of the second pump, the liquid phase polyphenylene ether to be decontaminated can be uniformly and continuously pumped into the centrifuge from the water washing kettle, thereby improving the working efficiency of the decontamination device.

[0065] To further optimize the technical solution, in order to ensure that the precipitant in the precipitation kettle can fully contact with the copper-containing polyphenylene ether, so that the copper ions can be fully precipitated and the copper ion impurity removal effect is optimized, in the technical solution provided in the embodiment of the present application, a stirring part is provided in the precipitation kettle; through stirring by the stirring part, the precipitant can be fully contacted with the copper ions and then precipitated, thereby better achieving the impurity removal effect on the copper ions.

[0066] Similarly, in a decontamination device in the present application, a stirring part is provided in the water washing kettle. The stirring part in the water washing kettle can fully mix the unfiltered copper-containing precipitate in the polyphenylene ether to be decontaminated in the water washing kettle with the water washing liquid, optimize the water washing effect of the water washing kettle, and ensure a good decontamination effect on copper ions.

[0067] The impurity removal device in the present application further includes: a third pump, which is arranged between the sedimentation tank and the sedimentation kettle. The third pump can speed up the flow rate of the impurity removal mixed system between the sedimentation kettle and the sedimentation tank, thereby speeding up the impurity removal work efficiency of the impurity removal device.

[0068] In order to realize the integrated treatment of impurity removal of polyphenylene, the impurity removal device in the present application also includes: a post-processing unit, which is connected to the liquid phase discharge end of the centrifuge; the post-processing unit includes: any one or more of a concentration part, a washing part and a drying part. After the impurity-removed polyphenylene ether is post-processed by concentration, washing and drying, a polyphenylene ether product is obtained.

[0069] To further optimize the technical solution, in terms of ensuring a good water washing effect of the water washing kettle, effectively improve the working efficiency of the water washing kettle, and achieve the water washing continuity of the water washing kettle, in the technical solution provided by the embodiment of the present application, a water washing liquid feed port is provided in the water washing kettle. Clean water washing liquid is continuously added to the water washing kettle through the water washing liquid feed port, which effectively ensures the water washing effect of the water washing kettle and can also achieve continuous water washing of the water washing kettle.

[0070] In the present application, in order to ensure the filtering effect of the filter unit, the particle size of the filter is 20 to 400 meshes.

[0071] In the present application, in order to ensure the centrifugal effect of the centrifuge, the centrifuge is a liquid-liquid two-phase centrifuge or a solid-liquid-liquid three-phase centrifuge.

[0072] Please refer again here Figure 1 , the impurity removal process of the metal ion impurity removal device provided in this application is briefly summarized.

[0073] The copper-containing polyphenylene ether logistics 1 to be removed enters the precipitation kettle R1, and the precipitant logistics 2 also enters the precipitation kettle R1. Under the action of the stirring part M, the logistics 1 and the logistics 2 are fully contacted in the precipitation kettle R1, and the copper ions in the logistics 1 are precipitated. After the precipitation is completed, the mixed system logistics 3 enters the precipitation tank V1 for further precipitation. After the precipitation is completed in the precipitation tank V1, the liquid phase logistics 5 enters the filter F1 for filtration. The solid phase precipitate logistics 4 in the precipitation tank V1 is discharged from the precipitation tank V1 and then subjected to other treatments.

[0074] In the filter F1, the liquid phase logistics 7 after filtration passes through the first pump B1, and the solid phase logistics 6 is discharged from the filter F1 for other treatments. The liquid phase logistics 8 passing through the first pump B1 enters the water washing kettle (the composition of logistics 7 and logistics 8 does not change here, and is only used to distinguish logistics flowing through different structures), and the washing liquid logistics 9 enters the water washing kettle. Under the stirring action of the stirring part M, logistics 8 and logistics 9 are fully in contact, and the solid phase impurities that have not been completely filtered in logistics 8 are washed away.

[0075] The liquid phase logistics 10 after washing in the water washing kettle passes through the second pump B2, and the liquid phase logistics 11 through the second pump B2 (the composition of logistics 10 and logistics 11 here has not changed, it is only used to distinguish the logistics flowing through different structures) enters the centrifuge M1 for centrifugation. The liquid phase logistics 13 after centrifugation is the polyphenylene ether after impurities are removed, and the solid phase logistics 12 after centrifugation is subjected to other treatments.

[0076] See here Figure 2 The present application provides a method for removing metal ions from polymer production, comprising:

[0077] Step 1, precipitation: the polymer solution to be decontaminated is mixed with a precipitant, and the liquid phase product is collected after precipitation to obtain a first product;

[0078] Step 2, filtration: filtering the first product to collect the liquid phase product to obtain the second product;

[0079] Step 3, water washing: washing the second product with water to collect the liquid phase product to obtain the third product;

[0080] Step 4, centrifugation: The third product is centrifuged to obtain a clean product.

[0081] In order to ensure the precipitation effect of the precipitant on the liquid to be removed, in the impurity removal method provided in the embodiment of the present application, in step one, the precipitant includes: alkali solution and / or carbonate aqueous solution.

[0082] To further optimize the precipitation effect, in the technical solution provided in the embodiment of the present application, in step 1, the alkali solution is a strong alkali aqueous solution, and the concentration of hydroxide ions in the alkali solution is 0.25-2.5 mol / L.

[0083] A more optimized technical solution is that in step 1, the concentration of hydroxide ions in the alkali solution is 1-2 mol / L.

[0084] To further optimize the precipitation effect, in the technical solution provided in the embodiment of the present application, in step 1, the carbonate aqueous solution is: sodium carbonate and / or sodium bicarbonate.

[0085] To further optimize the precipitation effect, in step 1, the concentration of bicarbonate ions in the carbonate aqueous solution is 0.25-2.5 mol / L; and / or the concentration of carbonate ions in the carbonate aqueous solution is 0.125-1.25 mol / L.

[0086] To further optimize the precipitation effect, in step 1, the concentration of bicarbonate ions in the carbonate aqueous solution is 1-2 mol / L; and / or the concentration of carbonate ions in the carbonate aqueous solution is 0.5-1.0 mol / L.

[0087] To further optimize the precipitation effect, in the technical solution provided in the embodiment of the present application, in step 1, the amount of the precipitant added is 1.5 wt% to 5.0 wt% of the polymer solution to be decontaminated.

[0088] To further optimize the precipitation effect, the amount of the precipitant added is 2.0-4.0 wt % of the polymer solution to be decontaminated.

[0089] In order to realize the integrated impurity removal processing for the product to be removed, an impurity removal method provided in an embodiment of the present application also includes: post-processing, in which the impurity-removed product is concentrated, washed and dried in sequence to obtain a post-processed impurity-removed product.

[0090] In the following, a specific example of removing impurities from polyphenylene ether containing metal ions is described in conjunction with a method for removing impurities in polymer production provided in the present application.

[0091] In Examples 1 to 4, the Figure 1 The process device shown in the figure has a volume of 0.8m 3 ; Sedimentation tank V1 is a cyclonic sedimentation tank with a volume of 1m 3 ; Filter F1 is a basket filter with a 200-mesh filter; V2 has a volume of 1.3m 3 The centrifuge is a solid-liquid-liquid three-phase centrifuge. The precipitant is a 1.5 mol / L NaOH aqueous solution. Please refer to Table 1 for the feed flow rate and copper ion content of logistics 1, the feed flow rate of logistics 2, the water feed flow rate of logistics 9, and the copper content of the polyphenylene ether product after impurity removal.

[0092] In Examples 5 to 8, the Figure 1 The process device shown in the figure has a volume of 0.8m 3 ; Sedimentation tank V1 is a cyclonic sedimentation tank with a volume of 1m 3 ; Filter F1 is a basket filter with a 200-mesh filter; V2 has a volume of 1.3m 3 The centrifuge is a solid-liquid-liquid three-phase centrifuge. The precipitant is a Na2CO3 aqueous solution with a carbonate concentration of 0.66 mol / L. Please refer to Table 1 for the feed flow rate and copper ion content of logistics 1, the feed flow rate of logistics 2, the water feed flow rate of logistics 9, and the copper content of the polyphenylene ether product after impurity removal.

[0093] Comparative Example 1 is different from Example 1 in that a 0.15 mol / L NaOH aqueous solution is used;

[0094] Comparative Example 2 is different from Example 5 in that a 0.07 mol / L Na2CO3 aqueous solution is used;

[0095] Comparative Example 3 is different from Example 1 in that a chelating agent is used to remove metal ions, specifically: the polyphenylene ether polymer solution of the synthesis section is filtered and washed with ethanol and water to remove acid to obtain a crude polyphenylene ether; the crude polyphenylene ether is added to 400g of toluene and stirred to dissolve, 80ml of a 5wt% tetrasodium ethylenediaminetetraacetic acid aqueous solution is added, the temperature is raised to 50°C and stirred for chelation reaction for 1h, and then allowed to stand for stratification. The oil phase is evaporated and concentrated under reduced pressure, filtered, washed and dried to obtain a polyphenylene ether product, and the copper content is measured as shown in Table 1.

[0096] Table 1

[0097]

[0098]

[0099] It can be concluded from Table 1 that the technical solution provided in the present application has a good effect on removing copper from copper-containing polyphenylene ether, and the polyphenylene ether will not be affected during the impurity removal process. The polyphenylene ether obtained by impurity removal has a stable structure, meets and exceeds the standards of high-quality polyphenylene ether products in the national standard, and is more suitable for application in the field of electronic components such as communications.

[0100] The present application also provides a method for removing metal ions in polymer production, which can effectively remove metal ion impurities in polyphenylene ether, especially copper ions that are often mixed in polyphenylene ether, and can be applied to removing impurities in polyphenylene ether.

[0101] In summary, the present application provides a method for removing metal ions from polymer production, including: precipitation, filtration, water washing and centrifugation. The present application also provides an application of the above-mentioned impurity removal method in the removal of polyphenylene ether. In the technical scheme provided by the present application, after the impurity-removing polymer solution is mixed with a precipitant, the mixed impurity metal ions are precipitated and precipitated, and then further filtered, washed and centrifuged to obtain a pure product after impurity removal. During the impurity removal process, the polyphenylene ether does not react, thereby ensuring the stability of the polyphenylene ether structure, and the generated metal ion precipitation structure is stable and not easy to decompose; it has been determined that the copper content in the polyphenylene ether after impurity removal is less than 2.0 mg / kg (or 2 ppm), which is lower than the copper content of less than 3 ppm required for commercially available high-quality polyphenylene ether products. Through the technical means of simple chemical precipitation coupled with physical separation, the technical defect of poor copper removal stability in the prior art of using a chelating agent to remove copper ions in polyphenylene ether is solved.

[0102] The technical features of the above-mentioned embodiments can be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above-mentioned embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification. At the same time, other implementation methods can be derived from the above-mentioned embodiments, so that structural and logical replacements and changes can be made without departing from the scope of this disclosure.

[0103] The above-described embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be construed as limiting the scope of the patent application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the patent application shall be subject to the attached claims.

Claims

1. A method for removing metal ions from polymer production, characterized in that: The impurity removal method comprises: Step 1, precipitation: the polymer solution to be decontaminated is mixed with a precipitant, and the liquid phase product is collected after precipitation to obtain a first product; Step 2, filtration: filtering the first product to collect the liquid phase product to obtain the second product; Step 3, washing with water: washing the second product with water to collect the liquid phase product to obtain the third product; Step 4, centrifugation: the third product is centrifuged to obtain a decontaminated product.

2. The impurity removal method according to claim 1, characterized in that: In step 1, the precipitant includes: alkali solution and / or carbonate aqueous solution.

3. The impurity removal method according to claim 2, characterized in that: In step 1, the alkali solution is a strong alkali aqueous solution, and the concentration of hydroxide ions in the alkali solution is 0.25-2.5 mol / L.

4. The impurity removal method according to claim 2 or 3, characterized in that: In step 1, the carbonate aqueous solution is: sodium carbonate and / or sodium bicarbonate.

5. The impurity removal method according to claim 4, characterized in that: In step 1, the concentration of bicarbonate ions in the carbonate aqueous solution is 0.25-2.5 mol / L; and / or, The carbonate ion concentration in the carbonate aqueous solution is 0.125-1.25 mol / L.

6. The impurity removal method according to any one of claims 1 to 5, characterized in that: In step 1, the amount of the precipitant added is 1.5 wt% to 5.0 wt% of the polymer solution to be decontaminated.

7. The impurity removal method according to claim 1, characterized in that: The impurity removal method further comprises: post-processing, wherein the impurity-removed product is concentrated, washed and dried in sequence to obtain a post-processed impurity-removed product.

8. Use of the impurity removal method according to any one of claims 1 to 7 in the impurity removal of polyphenylene ether.

9. The use according to claim 8, characterized in that: The application is the application of removing metal ions in polyphenylene ether.

10. The use according to claim 8 or 9, characterized in that: The application is the application of removing copper ions in polyphenylene ether.

11. The use according to claim 8, characterized in that: The polyphenylene ether product has a residual copper ion content of less than 2.0 mg / kg.

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