A polyaryletherketone copolymer and its preparation method

Abstract

This application relates to a polyaryletherketone copolymer and a method for preparing the same. The polyaryletherketone copolymer is basically composed of repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I; O-Ph-Ph-O-Ph-CO-Ph Formula II; wherein the molar ratio of the repeating units of Formula I to the repeating units of Formula II is 50:50 to 95:5, preferably 60:40 to 90:10, more preferably 70:30 to 85:15; and the polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.7.

Description

Technical Field

[0001] This application belongs to the field of polymer materials technology and relates to a polyaryletherketone copolymer and its preparation method. Background Technology

[0002] Polyaryletherketones (PAEKs), including polyetheretherketones (PEEK), polyetherketones (PEK), polyetherketoneketones (PEKK), and polyaryletherketone copolymers (PEEK-PEDEK), are a class of semi-crystalline thermoplastic polymers whose molecular backbone is composed of arylene groups, ether bonds, and ketone bonds. Due to their excellent high-temperature resistance, superior mechanical strength, outstanding chemical corrosion resistance, good flame retardancy, and radiation resistance, they are widely used in high-end fields such as aerospace, automotive manufacturing, electronics, and medical implants.

[0003] Currently, the most common industrial method for synthesizing polyaryletherketones (PAKs) is nucleophilic substitution polycondensation, which involves the polymerization of aromatic difluoro monomers and diphenols in a polar aprotic solvent under high temperature and an inert atmosphere to form a polymer. The traditional one-pot process involves adding all monomers (one or more diphenols, one or more aromatic difluoro monomers), solvents, and salt-forming agents to the same reactor at once. This one-pot method typically suffers from the following problems in preparing PAK copolymers: competitive salt formation, random structure of the resulting copolymer, increased side reactions, and difficulty in achieving high molecular weights.

[0004] Therefore, it is of great significance to develop a synthetic method that can overcome competitive salt formation, achieve controlled polymerization, and effectively suppress side reactions to obtain high molecular weight and structurally regular polyarylether ketone copolymers. Summary of the Invention

[0005] The purpose of this application is to provide a polyaryletherketone copolymer and a method for preparing the same.

[0006] In one aspect of this application, a polyaryletherketone copolymer is provided, which is essentially composed of repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I O-Ph-Ph-O-Ph-CO-Ph Formula II Wherein, the molar ratio of the repeating unit of Formula I to the repeating unit of Formula II is 50:50 to 95:5, preferably 60:40 to 90:10, more preferably 70:30 to 85:15; and The polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.7.

[0007] In some embodiments according to this application, the number-average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000, as determined by GPC.

[0008] In some embodiments according to this application, the L value of the polyaryletherketone copolymer, as determined by a colorimeter, is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5; the b value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45.

[0009] In some embodiments according to this application, the initial decomposition temperature of the polyaryletherketone copolymer is determined by thermogravimetric analysis to be at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C.

[0010] In some embodiments according to this application, the gel content of the polyaryletherketone copolymer is determined by filtration method to be at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%.

[0011] In some embodiments of this application, the absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160.

[0012] Another aspect of this application provides a method for preparing the above-mentioned polyaryletherketone copolymer, which includes the following steps: a) In the first reaction vessel, the first diphenol and the salt-forming agent are subjected to a first salt-forming reaction in the first polar aprotic solvent to obtain a first phenol salt solution; b) In a second reaction vessel, the second diphenol is reacted with a salt-forming agent in a second polar aprotic solvent to undergo a second salt-forming reaction, yielding a second phenol salt solution; the second diphenol is different from the first diphenol; c) Mix the aromatic difluorine monomer with the first polar aprotic solvent and / or the second polar aprotic solvent, and heat to form a homogeneous monomer solution; d) Transfer the first phenolic salt solution obtained in step a) and the second phenolic salt solution obtained in step b) to a polycondensation reactor containing the monomer solution obtained in step c) to carry out a polycondensation reaction to obtain the polyaryletherketone copolymer.

[0013] In some embodiments according to this application, the first salt-forming reaction and the second salt-forming reaction are carried out under an inert atmosphere at a temperature of 170°C to 240°C for 1.5 to 3 hours.

[0014] In some embodiments of this application, the first diphenol is selected from one or more of hydroquinone, resorcinol, catechol, and 2-methyl-1,4-hydroquinone, preferably hydroquinone; the second diphenol is selected from one or more of 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,4-naphthoquinone, 1,5-naphthoquinone, 2,6-naphthoquinone, and 2,7-naphthoquinone, preferably 4,4'-dihydroxybiphenyl.

[0015] In some embodiments according to this application, the salt-forming agent is an alkali metal carbonate or an alkali metal bicarbonate, preferably selected from one or more of potassium carbonate, sodium carbonate, cesium carbonate and potassium bicarbonate, and more preferably selected from one or more of potassium carbonate and sodium carbonate.

[0016] In some embodiments according to this application, the amount of the salt-forming agent is in excess of 1 mol% to 20 mol% relative to the total molar amount of diphenols in the system, preferably in excess of 5 mol% to 20 mol%.

[0017] In some embodiments of this application, the first polar aprotic solvent and the second polar aprotic solvent are independently selected from one or more of diphenyl sulfone, N-methylpyrrolidone and N,N-dimethylacetamide, preferably diphenyl sulfone.

[0018] In some embodiments of this application, the aromatic difluoro monomer is 4,4'-difluorobenzophenone or 2,4'-difluorobenzophenone, preferably 4,4'-difluorobenzophenone.

[0019] In some embodiments according to this application, the polycondensation reaction is carried out at a temperature of 300°C to 330°C for 2 to 4 hours.

[0020] In addition, this application also relates to polyaryletherketone copolymers obtained by the above method.

[0021] By independently forming salts of different phenol monomers under different reaction conditions, the reactivity was controlled, effectively avoiding competing reactions and side reactions, thereby synthesizing high molecular weight, narrow distribution, and more regular polyarylether ketone copolymers, which was difficult to anticipate before this application. Attached Figure Description

[0022] Figure 1 A flowchart of a method for preparing polyaryletherketone copolymers according to this application is shown. Detailed Implementation

[0023] The following detailed description, with appropriate reference to the accompanying drawings, discloses embodiments of the polyaryletherketone copolymer and its preparation method thereof. However, unnecessary details may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of essentially identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for the purpose of enabling those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0024] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0025] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0026] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0027] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0028] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0029] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0030] Unless otherwise specified, in this application, the terms "first," "second," "third," etc., are used to distinguish different objects, rather than to describe a specific order or primary / secondary relationship.

[0031] In this application, the terms "multiple", "various", etc., refer to two or more kinds.

[0032] Unless otherwise stated, the terms used in this application have the common meanings as commonly understood by those skilled in the art.

[0033] Unless otherwise stated, the values ​​of the parameters mentioned in this application can be determined using various testing methods commonly used in the art, for example, according to the testing methods given in the embodiments of this application. Unless otherwise stated, the test temperature is 25°C.

[0034] Polyaryletherketones (PAGEs) are a class of semi-crystalline thermoplastic polymers whose molecular backbone consists of arylene groups, ether bonds, and ketone bonds. Due to their excellent high-temperature resistance, superior mechanical strength, outstanding chemical corrosion resistance, good flame retardancy, and radiation resistance, they are widely used in high-end fields such as aerospace, automotive manufacturing, electronics, and medical implants. Currently, the most commonly used method for industrial preparation of PAGEs is nucleophilic substitution polymerization. When using diphenols with different reactivity to prepare PAGE copolymers, the traditional one-pot process involves adding all monomers, solvents, and salt-forming agents to the same reactor at once. This method has the following problems: 1. Competitive salt formation: Diphenols with different reactivity (such as hydroquinone and biphenyl) have different salt formation rates and equilibrium constants with salt-forming agents, resulting in uneven concentrations of phenolic salt active species in the reaction system; 2. Random structure: The difference in nucleophilic substitution activity of different phenol salts causes the monomer units in the copolymer chain to be randomly distributed, making it difficult to obtain a well-structured polymer chain, thereby impairing the crystallinity, melting point and mechanical properties of the product; 3. Increased side reactions: After the highly reactive phenolate reacts preferentially, the residual low-reactivity diphenols will lead to a local increase in alkalinity of the reaction medium, which may induce side reactions such as ether bond cleavage, resulting in a wider molecular weight distribution, polymer branching or cross-linking, and may also cause product discoloration. 4. High molecular weight is difficult to achieve: Due to the competition and interference between salt formation and condensation reactions, it is difficult to accurately control the stoichiometric balance, thus making it difficult to obtain ultra-high molecular weight PAEK products.

[0035] To address the aforementioned issues, the inventors of this application conducted extensive experiments and in-depth research, and surprisingly discovered that by independently forming salts of different phenol monomers under different reaction conditions, precise control of reactivity was achieved, effectively avoiding competing reactions and side reactions, thereby synthesizing polyaryletherketone copolymers with high molecular weight, narrow distribution, and more regular sequence structure.

[0036] Therefore, a first aspect of the embodiments of this application provides a polyaryletherketone copolymer, which is basically composed of repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I O-Ph-Ph-O-Ph-CO-Ph Formula II Wherein, the molar ratio of the repeating unit of Formula I to the repeating unit of Formula II is 50:50 to 95:5, preferably 60:40 to 90:10, more preferably 70:30 to 85:15; and The polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.7.

[0037] In the context of this application, “consistently of” means that, in addition to the listed components, the other components are present in an amount of up to 5% by weight, preferably up to 3% by weight, more preferably up to 1.5% by weight, and even more preferably up to 1% by weight.

[0038] In some embodiments of this application, the molar ratio of repeating units of Formula I to repeating units of Formula II in the polyaryletherketone copolymer is 50:50 to 95:5, preferably 60:40 to 90:10, more preferably 70:30 to 85:15, and even more preferably 70:30 to 80:20. Exemplarily, the molar ratio of repeating units of Formula I to repeating units of Formula II in the polyaryletherketone copolymer is 50:50, 55:45, 60:40, 65:35, 70:30, 75:25, 80:20, 85:15, 90:10, 95:5, etc., or within any range of two of the above values.

[0039] In this paper, the term "polydispersity index (PDI)" is a key parameter used to measure the breadth of the molecular weight distribution of a polymer. Its value is defined as the ratio of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the polymer (PDI = Mw / Mn).

[0040] In some embodiments of this application, the polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.7. Exemplarily, the PDI of the polyaryletherketone copolymer can be 3.0, 2.9, 2.8, 2.75, 2.7, 2.65, 2.6, 2.55, 2.5, 2.45, 2.4, 2.35, 2.3, 2.25, 2.2, 2.15, or within any range of two of the above values.

[0041] For the polyaryletherketone copolymer described in this application, the characteristic of PDI ≤ 3.0 directly indicates that it has a narrow and controllable molecular weight distribution. This gives it excellent melt stability and rheological behavior during processing, thus enabling the preparation of products with uniform structure and low internal stress. At the same time, the highly uniform molecular chain structure endows the material with more consistent and predictable mechanical strength, thermal stability, and long-term reliability, with overall performance significantly superior to similar materials with wider distributions.

[0042] In this document, the term "number-average molecular weight" has a meaning well-known in the field of polymer materials and can be determined by instruments and methods known in the art. As an example, gel permeation chromatography (GPC) is used, for instance, with an Agilent Technologies PL-GPC220 High Temperature GPC system, using α-chloronaphthalene as solvent and 1,2,4-trichlorobenzene as diluent; the column temperature is 125°C, and the mobile phase is a mixture of α-chloronaphthalene and 1,2,4-trichlorobenzene (mass ratio of α-chloronaphthalene to 1,2,4-trichlorobenzene = 1:2.2), with K = 14.2 and α = 0.72, to determine the number-average molecular weight of the sample.

[0043] In some embodiments of this application, the number average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000, preferably in the range of 19,000 to 40,000, more preferably in the range of 19,000 to 35,000, and most preferably in the range of 19,000 to 30,000. For example, the number-average molecular weight of the polyaryletherketone copolymer can be 18,000, 19,000, 20,000, 21,000, 22,000, 23,000, 24,000, 25,000, 26,000, 27,000, 28,000, 29,000, 30,000, 31,000, 32,000, 33,000, 34,000, 35,000, 36,000, 37,000, 38,000, 39,000, 40,000, 41,000, 42,000, 43,000, 44,000, 45,000, or within any two of the above values. When the number-average molecular weight of the polyaryletherketone copolymer is within the above range, the polyaryletherketone copolymer has appropriate mechanical strength, which is beneficial for forming products with excellent performance.

[0044] In some embodiments of this application, the L value of the polyaryletherketone copolymer is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5. Exemplarily, the L value of the polyaryletherketone copolymer, as measured by a colorimeter, can be 79.9, 80.0, 80.1, 80.2, 80.3, 80.4, 80.5, 80.6, 80.7, 80.8, 80.9, 81.0, 81.1, 81.2, 81.3, 81.4, 81.5, 81.6, 81.7, 81.8, 81.9, 82.0, 82.1, 82.2, 82.3, 82.4, 82.5, 82.6, or 82.7. 82.8, 82.9, 83.0, 83.1, 83.2, 83.3, 83.4, 83.5, 83.6, 83.7, 83.8, 83.9, 84.0, 84.1, 84.2, 84.3, 84.4, 84.5, 84.6, 84.7, 84.8, 84.9, 85.0, 85.5, 86.0, 86.5, 87.0, 87.5, 88.0, 88.5, 89.0, etc., or within the range formed by any two of the above values.

[0045] In color science, the L-value represents lightness, ranging from 0 (pure black) to 100 (pure white). Therefore, the high L-value (at least 79.9) of the polyaryletherketone copolymer directly characterizes the material's extremely high whiteness and visual clarity. This not only signifies excellent color and lower impurity content but also reflects the high precision and controllability of the polymerization and processing. This superior color stability is a comprehensive manifestation of the material's high internal homogeneity, controlled thermal history, and excellent purity, giving it significant aesthetic advantages and reliable quality in fields with stringent requirements for appearance quality, purity, and consistency.

[0046] In some embodiments of this application, the b-value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45. Exemplarily, measured by a colorimeter, the b-value of the polyaryletherketone copolymer can be 3.8, 3.75, 3.7, 3.65, 3.6, 3.55, 3.5, 3.45, 3.4, 3.35, 3.3, 3.25, 3.2, 3.15, 3.1, 3.05, 3.0, 2.95, 2.9, etc., or within a range formed by any two of the above values.

[0047] In color difference measurement systems, the b-value represents the yellow-blue index, with positive values ​​indicating a yellowish tint and negative values ​​indicating a bluish tint. Therefore, the low b-value (at most 3.8) of the polyaryletherketone copolymer directly characterizes the material's extremely low yellowness, resulting in a highly pure and near-neutral color. This stringent color control not only signifies a premium and clean visual appeal for the product but also reflects the material's excellent thermal stability and anti-aging properties, demonstrating its effective suppression of thermal degradation and yellowing tendencies during synthesis and high-temperature processing. This outstanding color stability gives it a competitive advantage and reliable quality assurance in fields with stringent requirements for appearance consistency, long-term durability, and high-quality perception (such as high-end electronic casings, precision optical components, and high-quality consumer goods).

[0048] In some embodiments of this application, the initial decomposition temperature of the polyaryletherketone copolymer, determined by thermogravimetric analysis, is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C. Exemplarily, the initial decomposition temperature of the polyaryletherketone copolymer, determined by thermogravimetric analysis, can be 565°C, 566°C, 567°C, 568°C, 569°C, 570°C, 571°C, 572°C, 573°C, 574°C, 575°C, 576°C, 577°C, 578°C, 579°C, 580°C, 581°C, 582°C, 583°C, 584°C, 585°C, 586°C, 587°C, 588°C, or within any two of the above values.

[0049] In thermogravimetric analysis, the initial decomposition temperature refers to the temperature at which a material begins to experience significant thermogravimetric loss during a programmed temperature rise process, and it is a core indicator for measuring the thermal stability of a material. Therefore, the high initial decomposition temperature (at least 565°C) of the polyaryletherketone copolymer directly characterizes its excellent heat resistance and thermal stability. This strictly controlled parameter not only means that the material can maintain structural integrity and performance stability at higher temperatures, but also reflects, more profoundly, the extremely strong bond energy, excellent chemical stability, and low content of easily decomposable impurities in its polymer chain structure. This thermal stability provides crucial long-term reliability and safety under extreme conditions such as continuous high temperatures, instantaneous high temperatures, or harsh thermal cycling.

[0050] In some embodiments of this application, the gel content of the polyaryletherketone copolymer, as determined by filtration, is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%. Exemplarily, the gel content of the polyaryletherketone copolymer, as determined by filtration, is 0.15%, 0.14%, 0.13%, 0.12%, 0.11%, 0.10%, 0.09%, 0.08%, 0.07%, 0.06%, 0.05%, 0.04%, 0.03%, or within any range of two of the above values.

[0051] Gel content refers to the mass percentage of cross-linked or giant molecular networks in a material that are insoluble in a specific solvent. It is a key indicator for measuring the purity and linear structural integrity of polymer solutions or melts. Therefore, the extremely low gel content (at most 0.15%) of the polyaryletherketone copolymer directly characterizes its extremely high chemical purity and highly regular molecular structure. This near-stringent control standard not only ensures excellent flow uniformity and superior film-forming ability during melt processing, but also reflects the high precision and controllability of its synthesis process, effectively avoiding performance defects caused by side reactions or impurities. This purity gives it a competitive advantage in fields with extreme requirements for dielectric properties or long-term durability.

[0052] In some embodiments of this application, the absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160. For example, the absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is 0.200, 0.190, 0.180, 0.170, 0.165, 0.160, 0.155, 0.154, 0.153, 0.152, 0.151, 0.150, 0.149, 0.148, 0.147, 0.146, 0.145, 0.144, 0.143, 0.142, 0.141, 0.140, 0.139, 0.138, 0.137, 0.136, 0.135, 0.134, 0.133, 0.133, 0.132, 0.131, 0.130, 0.125, 0.120, etc., or within the range formed by any two of the above values.

[0053] In ultraviolet-visible spectroscopy, absorbance refers to the degree to which light of a specific wavelength is absorbed by a material when it passes through a solution. It is a key optical indicator for quantitatively characterizing the concentration of impurities or chromophores in a solution. Therefore, the extremely low absorbance (at most 0.200) of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm directly characterizes the material's extremely high chemical purity and extremely low impurity content. This strictly controlled indicator not only means that the material is clearer and more stable in visual and optical performance, but also reflects the high degree of cleanliness and controllability of its polymerization process, effectively avoiding the formation of by-products or oxidized chromophores. This optical purity gives it a competitive advantage in fields with extremely stringent material requirements.

[0054] As described above, the inventors of this application have discovered that traditional one-pot copolymerization processes are difficult to precisely control the reaction process for phenolic monomers with different reactivity, easily leading to imbalances in the reactivity ratio and side reactions. To address this, the inventors have creatively proposed a core technical solution of stepwise independent salt formation: based on the unique acidity and steric hindrance of each phenolic monomer, it reacts separately with a salt-forming agent under differentiated temperature, time, or medium conditions to form phenolic salt intermediates with well-defined structures and uniform activity. This method enables the control of the activity and feeding sequence of each reaction site, thereby allowing different monomers to grow in a predetermined order and kinetic equilibrium during subsequent copolymerization reactions, effectively suppressing side reactions such as chain-end deactivation or sequence isomerization. The result is that the copolymer fundamentally ensures a high molecular weight, narrow molecular weight distribution, and highly regular chain sequence structure, ultimately achieving the theoretically designed performance of the material and exhibiting excellent batch repeatability.

[0055] Another aspect of this application provides a method for preparing the above-mentioned polyaryletherketone copolymer, the method comprising the following steps: a) In the first reaction vessel, the first diphenol and the salt-forming agent are subjected to a first salt-forming reaction in the first polar aprotic solvent to obtain a first phenol salt solution; b) In a second reaction vessel, the second diphenol is reacted with a salt-forming agent in a second polar aprotic solvent to undergo a second salt-forming reaction, yielding a second phenol salt solution; the second diphenol is different from the first diphenol; c) Mix the aromatic difluorine monomer with the first polar aprotic solvent and / or the second polar aprotic solvent, and heat to form a homogeneous monomer solution; d) Transfer the first phenolic salt solution obtained in step a) and the second phenolic salt solution obtained in step b) to a polycondensation reactor containing the monomer solution obtained in step c) to carry out a polycondensation reaction to obtain the polyaryletherketone copolymer.

[0056] Step a) above involves the salt formation process of the first phenol monomer. Specifically, in a first reaction vessel, a polar aprotic solvent, a first diphenol, and a salt-forming agent are added; under inert gas protection, the mixture is heated to a first salt-forming temperature T1 (typically 160-180°C) to carry out the salt-forming reaction for a reaction time of t1 (typically 1-4 hours), yielding a first phenol salt solution. The first aromatic diphenol is preferably a monomer with high reactivity. In some embodiments according to this application, the first diphenol is selected from one or more of hydroquinone, resorcinol, catechol, and 2-methyl-1,4-hydroquinone, preferably hydroquinone.

[0057] Step b) involves the salt formation process of the second phenol monomer. Specifically, in a second reaction vessel, a polar aprotic solvent, a second diphenol, and a salt-forming agent are added; under inert gas protection, the mixture is heated to a second salt-forming temperature T2 (typically 180-240°C) to carry out the salt-forming reaction for a reaction time of t2 (typically 1-4 hours), yielding a second phenol salt solution. The second diphenol is preferably a monomer with low reactivity. In some embodiments according to this application, the second diphenol is selected from one or more of 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,4-naphthol, 1,5-naphthol, 2,6-naphthol, and 2,7-naphthol, preferably 4,4'-dihydroxybiphenyl.

[0058] Of course, T1, T2, and t1 and t2 can be optimized and adjusted according to the differences and ratios of the activity of the diphenols.

[0059] Steps c) and d) involve the mixing and polycondensation reaction process. Specifically, a polar aprotic solvent and an aromatic difluoro monomer in approximately the same molar amount as the total diphenols are added to the polycondensation reactor and heated to a completely molten state. The first phenolate solution obtained in step a) and the second phenolate solution obtained in step b) are simultaneously transferred to the polycondensation reactor via a conveying system. Then, under vigorous stirring and an inert atmosphere, the reaction system is gradually heated to the polycondensation temperature T3 (typically 280-340°C), and the polycondensation reaction is carried out at this temperature for a time of t3 (typically 1-5 hours).

[0060] After the polycondensation reaction is completed, the resulting viscous material is cooled and pulverized to obtain a crude copolymer. Then, it can be extracted with an organic solvent (such as acetone or ethanol) to remove the solvent and low molecular weight byproducts, followed by washing with deionized water multiple times to remove inorganic salts, and finally dried to obtain a high-purity copolymer.

[0061] In some embodiments according to this application, the first salt-forming reaction and the second salt-forming reaction are carried out under an inert atmosphere at a temperature of 170°C to 240°C for 1.5 to 3 hours.

[0062] In some embodiments of this application, the first diphenol is selected from one or more of hydroquinone, resorcinol, catechol, and 2-methyl-1,4-hydroquinone, preferably hydroquinone; the second diphenol is selected from one or more of 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,4-naphthoquinone, 1,5-naphthoquinone, 2,6-naphthoquinone, and 2,7-naphthoquinone, preferably 4,4'-dihydroxybiphenyl.

[0063] In fact, the stepwise independent salt formation method disclosed in this application has technical advantages and applications not limited to binary copolymer systems. The core of this method lies in precise pre-activation and sequence control based on the differences in reactivity of different phenol monomers, a principle with universal applicability. When the system contains three or more diphenols with different structures and activities, the method of this application remains fully applicable and is particularly crucial.

[0064] In the case of multi-component copolymerization, the method naturally extends to include a corresponding number of independent salt-forming steps. By optimizing the salt-forming conditions for each phenolic monomer to match its chemical properties, the optimal precursor state for each reactant can be "customized." This allows for control of polymerization kinetics in subsequent polycondensation reactions, even when faced with more complex monomer combinations and competitive relationships, ensuring that each monomer participates in chain growth in a predetermined order and proportion.

[0065] Therefore, the method of this application provides an operable and efficient technical route for synthesizing binary, ternary, and even more diverse polyaryletherketone copolymers with well-defined and controllable structures. It significantly broadens the freedom of polymer molecular design, thereby meeting the increasingly complex demands for specialty engineering plastics in high-end fields.

[0066] Typically, the first salt-forming reactor, the second salt-forming reactor (and possibly more), are spatially positioned above the polycondensation reactor. The salt-forming reactor and the polycondensation reactor are connected by pipes and valves, which include heat tracing and insulation devices. Before the reaction begins, the salt-forming reactor, the polycondensation reactor, and the pipes are purged with nitrogen to ensure a continuous flow of nitrogen to protect the materials throughout the entire reaction process.

[0067] In some embodiments of this application, the salt-forming agent is an alkali metal carbonate or an alkali metal bicarbonate, preferably selected from one or more of sodium carbonate, potassium carbonate, cesium carbonate and potassium bicarbonate, more preferably selected from one or more of sodium carbonate and potassium carbonate, and most preferably a mixture of sodium carbonate and potassium carbonate. When the salt-forming agent is a mixture of sodium carbonate and potassium carbonate, the molar ratio of the two is in the range of 60-150:1, preferably in the range of 65-125:1, for example, 60:1, 65:1, 70:1, 72:1, 74:1, 75:1, 76:1, 78:1, 80:1, 82:1, 84:1, 85:1, 87:1, 90:1, 95:1, 100:1, 105:1, 110:1, 115:1, 120:1, 125:1, 130:1, 135:1, 140:1, 145:1, 150:1, etc., or within any two of the above values. Compared to single carbonates, this mixed alkali metal carbonate system can optimize the catalytic activity and compatibility of the reaction system through synergistic effects, effectively reduce the activation energy of the reaction, promote the full progress of nucleophilic condensation reaction, reduce the occurrence of side reactions, and improve the molecular weight and structural uniformity of the polymer.

[0068] In some embodiments according to this application, the amount of the salt-forming agent is in excess of 1 mol% to 20 mol% relative to the total molar amount of the diphenols in the system, preferably in excess of 5 mol% to 20 mol%. This excess range represents the balance point between effective salt formation and stable polycondensation. An appropriate excess (e.g., 1-20 mol%) ensures that all phenolic hydroxyl groups are fully converted to phenolate salts and provides the necessary alkaline buffer for the continuous neutralization of byproducts (e.g., hydrogen halides) during subsequent high-temperature polycondensation, thereby driving the reaction towards completion and inhibiting chain termination. Insufficient excess (<1%) may lead to incomplete reaction or a low molecular weight; however, within this preferred range, it ensures reaction kinetics while avoiding side reactions (e.g., hydrolysis or degradation) that may be caused by excessive alkalinity (e.g., excess much higher than 20%), thus providing a quantitative guarantee for achieving high conversion rates and high product quality.

[0069] In some embodiments according to this application, the first polar aprotic solvent and the second polar aprotic solvent are independently selected from one or more of diphenyl sulfone, N-methylpyrrolidone, and N,N-dimethylacetamide, preferably diphenyl sulfone. Preferably, the total weight of the solvents is 1.9 times or more the weight of the aromatic difluoro monomer, more preferably 2 times or more the weight of the aromatic difluoro monomer, and more preferably 2.5 times or more the weight of the aromatic difluoro monomer, but not exceeding 10 times. Controlling the solvent weight within the above range ensures that the viscosity of the reaction system is within an appropriate range while avoiding environmental pollution and increased costs caused by excessive solvent.

[0070] In some embodiments according to this application, the aromatic difluoro monomer is 4,4'-difluorobenzophenone or 2,4'-difluorobenzophenone, preferably 4,4'-difluorobenzophenone. The strong electron-withdrawing effect of the fluorine substituent can significantly enhance the electrophilicity of the carbonyl group, promote the efficient nucleophilic substitution reaction with the phenolic hydroxyl group, and the reaction byproduct (fluoride salt) is easily separated from the solvent. The symmetrical structure is more conducive to the formation of regular polymer segments, further ensuring the structural uniformity and performance stability of the material. Therefore, 4,4'-difluorobenzophenone is preferred.

[0071] In some embodiments according to this application, the molar ratio of the aromatic difluoro monomer to the total amount of the diphenol is in the range of 1.001-1.08:1, preferably in the range of 1.003-1.07:1, and more preferably in the range of 1.005-1.06:1.

[0072] In some embodiments according to this application, the polycondensation reaction is carried out at a temperature of 300°C to 330°C for 2 to 4 hours. This temperature range is sufficient to provide the activation energy required to overcome the reaction energy barrier and promote the full progress of nucleophilic substitution reactions on the aromatic ring, while ensuring that the reaction system is in a molten homogeneous state. The duration of 2 to 4 hours provides the necessary reaction time window for the gradual growth of high molecular weight polymers, achieving an optimal balance between avoiding insufficient polymerization due to too short a time or thermal degradation due to too long a time.

[0073] In summary, these optimized materials, proportions, and process conditions collectively constitute the technical solution for the efficient and controllable synthesis of high-performance polyaryletherketone copolymers presented in this application. Therefore, the preparation method according to this application has the following beneficial effects: 1) Avoid competing reactions: By salting two phenolic monomers with different activities in an independent environment, the competition between the two for the salting agent is completely eliminated, ensuring that each phenolic monomer can be completely converted into the corresponding phenolic salt, laying the foundation for achieving precise stoichiometric equilibrium. 2) Improve structural regularity: By controlling the addition method and order of the two phenolic salt solutions (which can be added simultaneously or in a specific order), the sequence structure of the polymer chain can be regulated at the molecular level, thereby obtaining copolymers with more regular structure and better performance. 3) Suppressing side reactions: The independent salt formation process ensures that the system is fully dehydrated before entering the high-temperature polycondensation stage, avoiding side reactions such as hydrolysis that may be caused in the presence of water; at the same time, it prevents the formation of local over-alkaline environment and reduces the generation of cross-linking byproducts. 4) Obtaining high molecular weight products: Due to precise stoichiometric control and fewer side reactions, this method can effectively promote the polycondensation reaction towards higher molecular weight, making it easier to obtain polyaryletherketone copolymers with high intrinsic viscosity and excellent mechanical properties. 5) High product quality: The resulting copolymer has a narrower molecular weight distribution, a lighter color (whiter), and lower impurity and ash content.

[0074] As described above, the stepwise independent salt formation method disclosed in this application has technical advantages and application scope that are not limited to binary copolymer systems. The core of this method lies in precise pre-activation and sequence control based on the differences in reactivity of different phenol monomers, and this principle has universality. When the system contains three or more binary phenols with different structures and activities, the method of this application is still fully applicable. Therefore, this application also relates to polyaryletherketone copolymers obtained by the method of this application. In some embodiments of this application, the polyaryletherketone copolymer satisfies one or more of the following (1)-(7): (1) The polyaryletherketone copolymer comprises at least repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I; O-Ph-Ph-O-Ph-CO-Ph Formula II; (2) The number average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000, as determined by GPC. (3) The L value of the polyaryletherketone copolymer is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5, as determined by a colorimeter; (4) The b value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45, as determined by a colorimeter; (5) The initial decomposition temperature of the polyaryletherketone copolymer is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C, as determined by thermogravimetric analysis. (6) The gel content of the polyaryletherketone copolymer is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%, as determined by filtration. (7) The absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160.

[0075] Example The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents used in the embodiments are commercially available or synthesized by conventional methods and can be used directly without further processing, and the instruments used in the embodiments are commercially available.

[0076] Test method: (1) Molecular weight distribution test: An Agilent Technologies PL-GPC220 HighTemperature Chromatograph was used with α-chloronaphthalene as solvent and 1,2,4-trichlorobenzene as diluent. The column temperature was 125℃, and the mobile phase was a mixture of α-chloronaphthalene and 1,2,4-trichlorobenzene with a mass ratio of α-chloronaphthalene:1,2,4-trichlorobenzene = 1:2.2. The test parameters were K = 14.2 and α = 0.72.

[0077] (2) Colorimetric test: Use a colorimeter to measure the L value, a value, and b value of the sample; (3) The degree of carbonyl branching in polyarylether ketone copolymers can be determined by the following methods: Accurately weigh 1.0 g of polyaryletherketone copolymer and add it to a 100 ml volumetric flask. Add 70 ml (95-98% by weight) of concentrated sulfuric acid to the flask, seal the flask and place it on a shaker for about 30 to 40 hours until dissolved. Add concentrated sulfuric acid to the 100 ml mark and shake the flask to obtain a homogeneous solution. The absorbance of the solution at 550 nm was measured using a UV spectrophotometer. The spectrophotometer was set to absorption mode, with a measurement range of 400 nm to 1000 nm, a data interval of 0.2 nm, a UV / Vis bandwidth of 1.5 nm, a scan rate of 100 nm / min, and a halogen D2 / WI light source.

[0078] (4) Gel content test: The gel content in the copolymer resin was determined using a filtration method. The specific steps are as follows: A. Take a certain mass of polyaryletherketone copolymer resin, keep it at 120℃ for 6 hours until the measured water content is ≤0.1%, take 1.0-1.5g of the above dried resin, accurately weigh it using an analytical balance, and record the mass as M0. Dissolve the weighed resin sample in trichlorotoluene solvent, seal it, and place it on a shaker at 180℃ for 30 hours to dissolve. B. Select a suitable microporous filter membrane that has been treated (soaked in formic acid solution until the mass is constant), with a pore size range of 0.2-0.4 micrometers, and record the mass of the filter membrane as M1; C. Install a sand core filter and a circulating water vacuum pump. During the filtration process, prevent contamination by foreign objects. D. Filter the resin solution. After filtration, rinse with a certain amount of deionized water and anhydrous ethanol. Remove the filter membrane and dry it to constant weight. Its mass is recorded as M2. The gel content in the resin is calculated using the following formula: Gel content = (M2-M1) / M0*100% (5) Thermal stability: Thermogravimetric analysis (TGA) was used to characterize the thermal stability of polyaryletherketone copolymer resin. The initial decomposition temperature determined by TGA was used as the indicator of the thermal stability of the resin because the initial decomposition temperature is the temperature at which the TGA curve begins to deviate from the baseline point and has good repeatability.

[0079] Example 1 Nitrogen gas was continuously introduced into a 5L reactor (first salt-forming reactor) connected to a water separator, condenser, and stirrer. 2102.93g (9.63mol) diphenyl sulfone, 1057.06g (9.6mol) hydroquinone, 1170.13g (11.04mol) sodium carbonate, and 19.90g (0.144mol) potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 180℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0080] Nitrogen gas was continuously introduced into a 3L reactor (second salt-forming reactor) connected to a water separator, condenser, and stirrer. 696.66g (3.19mol) of diphenyl sulfone, 446.90g (2.4mol) of 4,4'-dihydroxybiphenyl, 292.53g (2.76mol) of sodium carbonate, and 4.98g (0.036mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 210℃ for 2.0 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0081] Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser and stirrer. 2450.41g (11.23mol) of diphenyl sulfone and 2618.39g (12mol) of 4,4'-difluorobenzophenone were added. After the mixture was heated to the point of melting, the stirring was started at a speed of 80r / min. The temperature was raised to 210℃ and maintained.

[0082] After the salt formation reaction is completed, the materials from the first and second salt formation reactors are sequentially transferred to the polymerization reactor. The stirring speed is maintained at 80 r / min, and the temperature is raised to 310℃ and held at this temperature for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N1, 4,4'-difluorobenzophenone (10.91 g, 0.050 mol) is added in one go for end-capping treatment. After another 30 minutes, the discharge valve is opened, and the mixture in the polymerization reactor is quickly poured onto a smooth stainless steel plate for cooling. The cooled material is ground and pulverized (maximum size <2 mm), washed 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, and then washed 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm. The washed material is then placed in a stainless steel tray and dried in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0083] Example 2 Nitrogen gas was continuously introduced into a 5L reactor (first salt-forming reactor) connected to a water separator, condenser, and stirrer. 1955.58g (8.96mol) diphenyl sulfone, 990.99g (9.0mol) hydroquinone, 1097.0g (10.35mol) sodium carbonate, and 18.66g (0.135mol) potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 180℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0084] Nitrogen gas was continuously introduced into a 3L reactor (second salt-forming reactor) connected to a water separator, condenser, and stirrer. 863.79g (3.96mol) of diphenyl sulfone, 558.63g (3.0mol) of 4,4'-dihydroxybiphenyl, 365.66g (3.45mol) of sodium carbonate and 6.22g (0.045mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 220℃ for 2.0 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0085] Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser and stirrer. 2430.63g (11.14mol) of diphenyl sulfone and 2618.39g (12.0mol) of 4,4'-difluorobenzophenone were added. After the mixture was heated to the point of melting, the stirring was started at a speed of 80r / min and the temperature was raised to 220℃ and maintained at that temperature.

[0086] After the salt formation reaction is completed, the materials from the first and second salt formation reactors are transferred sequentially to the polymerization reactor. The stirring speed is maintained at 80 r / min, and the temperature is raised to 310℃ and held at this temperature for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N2, 4,4'-difluorobenzophenone (10.91 g, 0.050 mol) is added in one go for end-capping treatment. After another 30 minutes, the discharge valve is opened, and the mixture in the polymerization reactor is quickly poured onto a smooth stainless steel plate for cooling. The cooled material is then ground and pulverized (maximum size <2 mm), washed 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, and washed 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm. The washed material is then placed in a stainless steel tray and dried in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0087] Example 3 Nitrogen gas was continuously introduced into a 5L reactor (first salt-forming reactor) connected to a water separator, condenser, and stirrer. 1667.91g (7.64mol) diphenyl sulfone, 858.86g (7.80mol) hydroquinone, 950.73g (8.97mol) sodium carbonate, and 16.17g (0.117mol) potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 175℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0088] Nitrogen gas was continuously introduced into a 3L reactor (second salt-forming reactor) connected to a water separator, condenser, and stirrer. 1190.09g (5.45mol) of diphenyl sulfone, 782.08g (4.20mol) of 4,4'-dihydroxybiphenyl, 511.93g (4.83mol) of sodium carbonate, and 8.71g (0.063mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 230℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0089] Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 2392.01g (10.96mol) of diphenyl sulfone and 2618.39g (12.0mol) of 4,4'-difluorobenzophenone were added. After the mixture was heated to the point of melting, the stirring was started at a speed of 80r / min. The temperature was raised to 230℃ and maintained at that temperature.

[0090] After the salt formation reaction is completed, the materials from the first and second salt formation reactors are transferred sequentially to the polymerization reactor. The stirring speed is maintained at 80 r / min, and the temperature is raised to 310℃ and held at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N3, 4,4'-difluorobenzophenone (10.91 g, 0.050 mol) is added in one go for end-capping treatment. After another 30 minutes, the discharge valve is opened, and the mixture in the polymerization reactor is quickly poured onto a smooth stainless steel plate for cooling. The cooled material is ground and pulverized (maximum size <2 mm), washed 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, and then washed 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm. The washed material is then placed in a stainless steel tray and dried in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0091] Example 4 Nitrogen gas was continuously introduced into a 5L reactor (first salt-forming reactor) connected to a water separator, condenser, and stirrer. 1349.54g (6.18mol) diphenyl sulfone, 726.73g (6.60mol) hydroquinone, 804.46g (7.59mol) sodium carbonate, and 13.68g (0.099mol) potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 170℃ for 2 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0092] Nitrogen gas was continuously introduced into a 5L reactor (second salt-forming reactor) connected to a water separator, condenser, and stirrer. 1463.15g (6.70mol) of diphenyl sulfone, 1005.53g (5.40mol) of 4,4'-dihydroxybiphenyl, 658.20g (6.21mol) of sodium carbonate, and 11.20g (0.081mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80r / min and maintained at 235℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0093] Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 2287.32g (10.48mol) of diphenyl sulfone and 2618.39g (12.0mol) of 4,4'-difluorobenzophenone were added. After the mixture was heated to the point of melting, the stirring was started at a speed of 80r / min, and the temperature was raised to 235℃ and maintained.

[0094] After the salt formation reaction is completed, the materials from the first and second salt formation reactors are transferred sequentially to the polymerization reactor. The stirring speed is maintained at 80 r / min, and the temperature is raised to 310℃ and held at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N4, 4,4'-difluorobenzophenone (10.91 g, 0.050 mol) is added in one go for end-capping treatment. After another 30 minutes, the discharge valve is opened, and the mixture in the polymerization reactor is quickly poured onto a smooth stainless steel plate for cooling. The cooled material is then ground and pulverized (maximum size <2 mm), washed 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, and washed 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm. The washed material is then placed in a stainless steel tray and dried in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0095] Comparative Example 1 Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 5250.0g (24.05mol) of diphenyl sulfone, 2618.39g (12.0mol) of 4,4'-difluorobenzophenone, 1057.06g (9.6mol) of hydroquinone, 446.90g (2.4mol) of 4,4'-dihydroxybiphenyl, 1462.66g (13.8mol) of sodium carbonate, and 24.88g (0.18mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80 r / min. The temperature was raised to 180℃, maintained at 180℃ for 2 hours, then raised to 220℃, maintained at 220℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0096] Maintain a stirring speed of 80 r / min, raise the temperature to 310℃, and hold at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N5, add 10.91 g (0.050 mol) of 4,4'-difluorobenzophenone for end-capping treatment. After another 30 minutes, open the discharge valve and quickly pour the mixture in the polymerization reactor onto a smooth stainless steel plate for cooling. Grind the cooled material (maximum size <2 mm), wash it 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, wash it 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm, and place the washed material into a stainless steel tray and dry it in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0097] Comparative Example 2 Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 5250.0g (24.05mol) of diphenyl sulfone, 2618.39g (12.0mol) of 4,4'-difluorobenzophenone, 990.99g (9.0mol) of hydroquinone, 558.63g (3.0mol) of 4,4'-dihydroxybiphenyl, 1462.66g (13.8mol) of sodium carbonate, and 24.88g (0.18mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80 r / min. The temperature was raised to 180℃, maintained at 180℃ for 2 hours, then raised to 220℃, maintained at 220℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0098] Maintain a stirring speed of 80 r / min, raise the temperature to 310℃, and hold at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N6, add 10.91 g (0.050 mol) of 4,4'-difluorobenzophenone for end-capping treatment. After another 30 minutes, open the discharge valve and quickly pour the mixture in the polymerization reactor onto a smooth stainless steel plate for cooling. Grind the cooled material (maximum size <2 mm), wash it 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, wash it 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm, and place the washed material into a stainless steel tray and dry it in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0099] Comparative Example 3 Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 5250.0g (24.05mol) of diphenyl sulfone, 2618.39g (12.0mol) of 4,4'-difluorobenzophenone, 858.86g (7.8mol) of hydroquinone, 782.08g (4.2mol) of 4,4'-dihydroxybiphenyl, 1462.66g (13.8mol) of sodium carbonate, and 24.88g (0.18mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80 r / min. The temperature was raised to 180℃, maintained at 180℃ for 2 hours, then raised to 220℃, maintained at 220℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0100] Maintain a stirring speed of 80 r / min, raise the temperature to 310℃, and hold at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N7, add 10.91 g (0.050 mol) of 4,4'-difluorobenzophenone for end-capping treatment. After another 30 minutes, open the discharge valve and quickly pour the mixture in the polymerization reactor onto a smooth stainless steel plate for cooling. Grind the cooled material (maximum size <2 mm), wash it 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, wash it 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm, and place the washed material into a stainless steel tray and dry it in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0101] Comparative Example 4 Nitrogen gas was continuously introduced into a 15L reactor (polymerization reactor) connected to a water separator, condenser, and stirrer. 5100.0g (23.37mol) of diphenyl sulfone, 2618.39g (12.0mol) of 4,4'-difluorobenzophenone, 726.73g (6.6mol) of hydroquinone, 1005.53g (5.4mol) of 4,4'-dihydroxybiphenyl, 1462.66g (13.8mol) of sodium carbonate, and 24.88g (0.18mol) of potassium carbonate were added. After heating to the point of melting, stirring was started at 80 r / min. The temperature was raised to 180℃, maintained at 180℃ for 2 hours, then raised to 220℃, maintained at 220℃ for 2.5 hours. The generated water and gas were condensed by the condenser and separated by the water separator.

[0102] Maintain a stirring speed of 80 r / min, raise the temperature to 310℃, and hold at 310℃ for 1-2 hours. When the torque value of the stirrer's torque sensor reaches the target value N8, add 10.91 g (0.050 mol) of 4,4'-difluorobenzophenone for end-capping treatment. After another 30 minutes, open the discharge valve and quickly pour the mixture in the polymerization reactor onto a smooth stainless steel plate for cooling. Grind the cooled material (maximum size <2 mm), wash it 5-7 times with pure acetone until diphenyl sulfone is no longer detected in the acetone washing solution, wash it 5-7 times with deionized water at 68-76℃ until the conductivity of the washing solution is <3 μS / cm, and place the washed material into a stainless steel tray and dry it in an oven at 150℃ for 8 hours to obtain the PEEK-PEDEK copolymer.

[0103] The torque values ​​in the above embodiments and comparative examples may be the same or different. Those skilled in the art can make reasonable selections based on specific experimental equipment, experimental conditions, and conventional operating experience.

[0104] The copolymers of the examples and comparative examples were tested according to the above test methods, and the results are shown in Tables 1 to 5 below.

[0105] Table 1. Color test results of polyaryletherketone copolymers

[0106] According to the color test results in Table 1, there are significant differences in the L and b values ​​between the example samples and the comparative samples in terms of color parameters. Specifically, the L value of the example samples is significantly higher, indicating better brightness and a lighter color; while the b value of the comparative samples is significantly higher, indicating a more yellowish color. Overall, the comparative samples are darker and more yellowish, which is likely related to their lower thermal stability and greater susceptibility to oxidative degradation.

[0107] Table 2. TGA test results of polyaryletherketone copolymers

[0108] According to the test results in Table 2, the polyaryletherketone copolymer resins prepared according to the embodiments of this application are superior in thermal stability to the polyaryletherketone copolymer resins prepared in the comparative examples.

[0109] Table 3. Molecular weight distribution of polyaryletherketone copolymers

[0110] According to the test results in Table 3, the PDI value of the polyaryletherketone copolymer prepared according to the embodiments of this application is significantly lower than that of the comparative sample, indicating that the polyaryletherketone copolymer of the embodiments has a narrower molecular weight distribution.

[0111] Table 4. Test results of gel content of polyaryletherketone copolymer resin

[0112] According to the test results in Table 4, the gel content of the polyaryletherketone copolymer prepared according to the embodiments of this application is significantly lower than that of the polyaryletherketone copolymer in the comparative example, indicating that the polyaryletherketone copolymer of the embodiments exhibits higher purity.

[0113] Table 5. Branching degree test results of polyaryletherketone copolymers

[0114] As shown in Table 5, the concentrated sulfuric acid solution of the polyaryletherketone copolymer according to the embodiments of this application has a significantly lower absorbance at 550 nm than the comparative example. The lower absorbance directly reflects the lower degree of polymer chain branching and higher structural regularity, indicating that it possesses superior intrinsic quality.

[0115] Some exemplary implementations are described below: Implementation Method 1. A polyaryletherketone copolymer, which is basically composed of repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I O-Ph-Ph-O-Ph-CO-Ph Formula II Wherein, the molar ratio of the repeating unit of Formula I to the repeating unit of Formula II is 50:50 to 95:5, preferably 60:40 to 85:15, more preferably 70:30 to 90:10; and The polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.7.

[0116] Embodiment 2. The polyaryletherketone copolymer according to Embodiment 1, wherein the number-average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000 as determined by GPC.

[0117] Embodiment 3. The polyaryletherketone copolymer according to Embodiment 1 or 2, wherein, as measured by a colorimeter, the L value of the polyaryletherketone copolymer is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5.

[0118] Embodiment 4. The polyaryletherketone copolymer according to any one of Embodiments 1 to 3, wherein, as determined by a colorimeter, the b-value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45.

[0119] Embodiment 5. The polyaryletherketone copolymer according to any one of Embodiments 1 to 4, wherein the initial decomposition temperature of the polyaryletherketone copolymer, as determined by thermogravimetric analysis, is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C.

[0120] Embodiment 6. The polyaryletherketone copolymer according to any one of Embodiments 1 to 5, wherein, as determined by filtration, the gel content of the polyaryletherketone copolymer is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%.

[0121] Embodiment 7. The polyaryletherketone copolymer according to any one of Embodiments 1 to 6, wherein the absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160.

[0122] Embodiment 8. A method for preparing the polyaryletherketone copolymer according to any one of Embodiments 1 to 7, comprising the following steps: a) In the first reaction vessel, the first diphenol and the salt-forming agent are subjected to a first salt-forming reaction in the first polar aprotic solvent to obtain a first phenol salt solution; b) In a second reaction vessel, the second diphenol is reacted with a salt-forming agent in a second polar aprotic solvent to undergo a second salt-forming reaction, yielding a second phenol salt solution; the second diphenol is different from the first diphenol; c) Mix the aromatic difluorine monomer with the first polar aprotic solvent and / or the second polar aprotic solvent, and heat to form a homogeneous monomer solution; d) Transfer the first phenolic salt solution obtained in step a) and the second phenolic salt solution obtained in step b) to a polycondensation reactor containing the monomer solution obtained in step c) to carry out a polycondensation reaction to obtain the polyaryletherketone copolymer.

[0123] Implementation Method 9. According to the method of Implementation Method 8, wherein the first salt formation reaction and the second salt formation reaction are carried out under an inert atmosphere at a temperature of 170°C to 240°C for 1.5 to 3 hours.

[0124] Embodiment 10. The method according to Embodiment 8 or 9, wherein the first diphenol is selected from one or more of hydroquinone, resorcinol, catechol and 2-methyl-1,4-hydroquinone, preferably hydroquinone; the second diphenol is selected from one or more of 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,4-naphthoquinone, 1,5-naphthoquinone, 2,6-naphthoquinone and 2,7-naphthoquinone, preferably 4,4'-dihydroxybiphenyl.

[0125] Embodiment 11. The method according to any one of Embodiments 8 to 10, wherein the salt-forming agent is an alkali metal carbonate or an alkali metal bicarbonate, preferably selected from one or more of potassium carbonate, sodium carbonate, cesium carbonate and potassium bicarbonate, and more preferably selected from one or more of potassium carbonate and sodium carbonate.

[0126] Implementation Method 12. The method according to any one of Implementation Methods 8 to 11, wherein the amount of the salt-forming agent is in excess of 1 mol% to 20 mol% relative to the total molar amount of the diphenols in the system, preferably in excess of 5 mol% to 20 mol%.

[0127] Embodiment 13. The method according to any one of Embodiments 8 to 12, wherein the first polar aprotic solvent and the second polar aprotic solvent are independently selected from one or more of diphenyl sulfone, N-methylpyrrolidone and N,N-dimethylacetamide, preferably diphenyl sulfone.

[0128] Embodiment 14. The method according to any one of Embodiments 8 to 13, wherein the aromatic difluoro monomer is 4,4'-difluorobenzophenone or 2,4'-difluorobenzophenone, preferably 4,4'-difluorobenzophenone.

[0129] Implementation Method 15. The method according to any one of Implementation Methods 8 to 14, wherein the polycondensation reaction is carried out at a temperature of 300°C to 330°C for 2 to 4 hours.

[0130] Embodiment 16. A polyaryletherketone copolymer obtained by the method according to any one of Embodiments 8 to 15.

[0131] Embodiment 17. The polyaryletherketone copolymer according to Embodiment 16, wherein the polyaryletherketone copolymer satisfies one or more of the following (1)-(7): (1) The polyaryletherketone copolymer comprises at least repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I; O-Ph-Ph-O-Ph-CO-Ph Formula II; (2) The number average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000, as determined by GPC. (3) The L value of the polyaryletherketone copolymer is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5, as determined by a colorimeter; (4) The b value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45, as determined by a colorimeter; (5) The initial decomposition temperature of the polyaryletherketone copolymer is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C, as determined by thermogravimetric analysis. (6) The gel content of the polyaryletherketone copolymer is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%, as determined by filtration. (7) The absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160.

[0132] Although this application has been described with reference to numerous embodiments and examples, those skilled in the art will recognize from the disclosure of this application that other embodiments can be designed without departing from the protection scope of this application.

Claims

1. A polyaryletherketone copolymer, which is basically composed of repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I O-Ph-Ph-O-Ph-CO-Ph Formula II Wherein, the molar ratio of the repeating unit of Formula I to the repeating unit of Formula II is 50:50 to 95:5, preferably 60:40 to 85:15, more preferably 70:30 to 90:10; and The polydispersity index (PDI) of the polyaryletherketone copolymer is at most 3.0, preferably at most 2.9, more preferably at most 2.8, and most preferably at most 2.

7.

2. The polyaryletherketone copolymer according to claim 1, wherein, The number-average molecular weight of the polyaryletherketone copolymer, as determined by GPC, is in the range of 18,000 to 45,000.

3. The polyaryletherketone copolymer according to claim 1 or 2, wherein, The L value of the polyaryletherketone copolymer, as determined by a colorimeter, is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.

5.

4. The polyaryletherketone copolymer according to any one of claims 1 to 3, wherein, The b-value of the polyaryletherketone copolymer, as determined by a colorimeter, is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.

45.

5. The polyaryletherketone copolymer according to any one of claims 1 to 4, wherein, The initial decomposition temperature of the polyaryletherketone copolymer, as determined by thermogravimetric analysis, is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C.

6. The polyaryletherketone copolymer according to any one of claims 1 to 5, wherein, The gel content of the polyaryletherketone copolymer, as determined by filtration, is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%.

7. The polyaryletherketone copolymer according to any one of claims 1 to 6, wherein, The absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.

160.

8. A method for preparing the polyaryletherketone copolymer according to any one of claims 1 to 7, comprising the following steps: a) In the first reaction vessel, the first diphenol and the salt-forming agent are subjected to a first salt-forming reaction in the first polar aprotic solvent to obtain a first phenol salt solution; b) In a second reaction vessel, the second diphenol is reacted with a salt-forming agent in a second polar aprotic solvent to undergo a second salt-forming reaction, yielding a second phenol salt solution; the second diphenol is different from the first diphenol; c) Mix the aromatic difluorine monomer with the first polar aprotic solvent and / or the second polar aprotic solvent, and heat to form a homogeneous monomer solution; d) Transfer the first phenolic salt solution obtained in step a) and the second phenolic salt solution obtained in step b) to a polycondensation reactor containing the monomer solution obtained in step c) to carry out a polycondensation reaction to obtain the polyaryletherketone copolymer.

9. The method according to claim 8, wherein, The first salt formation reaction and the second salt formation reaction were carried out under an inert atmosphere at a temperature of 170°C to 240°C for 1.5 to 3 hours.

10. The method according to claim 8 or 9, wherein, The first diphenol is selected from one or more of hydroquinone, resorcinol, catechol and 2-methyl-1,4-hydroquinone, preferably hydroquinone; the second diphenol is selected from one or more of 2,2'-dihydroxybiphenyl, 3,3'-dihydroxybiphenyl, 4,4'-dihydroxybiphenyl, 1,4-naphthoquinone, 1,5-naphthoquinone, 2,6-naphthoquinone and 2,7-naphthoquinone, preferably 4,4'-dihydroxybiphenyl.

11. The method according to any one of claims 8 to 10, wherein, The salt-forming agent is an alkali metal carbonate or an alkali metal bicarbonate, preferably selected from one or more of potassium carbonate, sodium carbonate, cesium carbonate and potassium bicarbonate, and more preferably selected from one or more of potassium carbonate and sodium carbonate.

12. The method according to any one of claims 8 to 11, wherein, The amount of the salt-forming agent used is 1 mol% to 20 mol excess relative to the total molar amount of diphenols in the system, preferably 5 mol% to 20 mol excess.

13. The method according to any one of claims 8 to 12, wherein, The first polar aprotic solvent and the second polar aprotic solvent are independently selected from one or more of diphenyl sulfone, N-methylpyrrolidone and N,N-dimethylacetamide, preferably diphenyl sulfone.

14. The method according to any one of claims 8 to 13, wherein, The aromatic difluoro monomer is 4,4'-difluorobenzophenone or 2,4'-difluorobenzophenone, preferably 4,4'-difluorobenzophenone.

15. The method according to any one of claims 8 to 14, wherein, The polycondensation reaction is carried out at a temperature of 300°C to 330°C for 2 to 4 hours.

16. A polyaryletherketone copolymer obtained by the method according to any one of claims 8 to 15.

17. The polyaryletherketone copolymer according to claim 16, wherein, The polyaryletherketone copolymer satisfies one or more of the following (1)-(7): (1) The polyaryletherketone copolymer comprises at least repeating units of Formula I and repeating units of Formula II: O-Ph-O-Ph-CO-Ph Formula I; O-Ph-Ph-O-Ph-CO-Ph Formula II; (2) The number average molecular weight of the polyaryletherketone copolymer is in the range of 18,000 to 45,000, as determined by GPC. (3) The L value of the polyaryletherketone copolymer is at least 79.9, preferably at least 80.0, more preferably at least 80.1, even more preferably at least 80.3, and most preferably at least 80.5, as determined by a colorimeter; (4) The b value of the polyaryletherketone copolymer is at most 3.8, preferably at most 3.7, more preferably at most 3.6, even more preferably at most 3.5, and most preferably at most 3.45, as determined by a colorimeter; (5) The initial decomposition temperature of the polyaryletherketone copolymer is at least 565°C, preferably at least 568°C, more preferably at least 569°C, and even more preferably at least 570°C, as determined by thermogravimetric analysis. (6) The gel content of the polyaryletherketone copolymer is at most 0.15%, preferably at most 0.10%, more preferably at most 0.08%, even more preferably at most 0.07%, and most preferably at most 0.06%, as determined by filtration. (7) The absorbance of the concentrated sulfuric acid solution of the polyaryletherketone copolymer at 550 nm is at most 0.200, preferably at most 0.190, more preferably at most 0.180, even more preferably at most 0.170, and most preferably at most 0.160.

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