A low-cost, high-performance poly(arylene ether ketone (nitrile)) resin, and a preparation method and application thereof

Abstract

The application discloses a low-cost and high-performance polyarylene ether ketone (nitrile) resin and a preparation method and application thereof, and belongs to the technical field of special polymer materials. The low-cost 4,4'-difluorobenzophenone is prepared by using a solid acid catalyst in a fixed bed reactor starting from polymerization raw materials, and then, the low-cost and high-performance polyarylene ether ketone (nitrile) resin is prepared by a polycondensation reaction of the 4,4'-difluorobenzophenone and other fluorine-containing monomers, bisphenol compounds, etc. The polymer material has the characteristics of excellent mechanical performance, good processing performance, low crystallinity, good flame-retardant performance and low cost, etc. and can be widely applied in the fields of military industry, aerospace, automobiles and electronics, etc. and has good application prospect and market value.

Description

Technical Field

[0001] This invention relates to a low-cost, high-performance polyaryletherketone (nitrile) resin, its preparation method, and its applications, belonging to the field of special polymer materials technology. Background Technology

[0002] Specialty polymer materials are a class of high-end polymer compounds that exhibit superior comprehensive performance under harsh working conditions and special application scenarios. Typical examples include polyetheretherketone (PEEK), polyimide (PI), polyphenylene sulfone (PPSU), polyetherimide (PEI), polyethersulfone (PES), and polyphenylene sulfide (PPS). As ideal alternatives and upgrades to traditional materials, these materials can be widely used in emerging fields such as robotics, automotive lightweighting, aerospace, 6G communications, and additive manufacturing (3D printing), possessing extremely high technological added value and broad market application prospects.

[0003] Traditional polyetheretherketone (PEEK) is widely used in the field of engineering plastics due to its excellent comprehensive properties. It has become the preferred material for key core components such as aircraft bearings and engine blades, ensuring long-term stable operation and ultra-long service life under extreme working conditions. However, the price of PEEK materials remains high, with domestic products averaging around 350,000 to 500,000 yuan per ton, and imported products even more expensive. In addition, the material itself has high crystallinity and high melt viscosity, resulting in problems such as high polymerization and processing temperatures, high energy consumption, low processing efficiency, and stringent requirements for monomer purity, which greatly restricts its further promotion and large-scale application. Summary of the Invention

[0004] Objectives of the Invention: The first objective of this invention is to provide a low-cost, high-performance method for preparing polyaryletherketone (nitrile) resin; the second objective of this invention is to provide a low-cost, high-performance polyaryletherketone (nitrile) resin; the third objective of this invention is to provide applications of the aforementioned low-cost, high-performance polyaryletherketone (nitrile) resin; and to solve the technical problems that existing polyetheretherketone materials are expensive, have poor processing performance, and require strict monomer purity, thus restricting their large-scale application.

[0005] Technical solution: The present invention provides a method for preparing a low-cost, high-performance polyaryletherketone (nitrile) resin, comprising the following steps:

[0006] (1) Synthesis and purification of low-cost 4,4'-difluorobenzophenone: fluorobenzene and p-fluorobenzoyl chloride were used as starting materials and reacted under the action of solid acid catalyst. The resulting reaction mixture was separated by stepwise distillation under different temperature conditions. The fluorobenzene was recovered and high-purity 4,4'-difluorobenzophenone was obtained.

[0007] (2) Polycondensation reaction: Under inert gas protection and light-proof conditions, 4,4'-difluorobenzophenone, fluorinated monomers and bisphenol compounds, alkali metal carbonates and solvents prepared in step (1) are mixed and polymerized by heating in stages. After the reaction is completed, the product is cooled and solidified to obtain crude polyarylether ketone (nitrile) resin.

[0008] (3) Post-processing: The polyaryletherketone (nitrile) resin is crushed, washed and dried to obtain a low-cost, high-performance polyaryletherketone (nitrile) resin product.

[0009] Further, in step (1), the molar ratio of fluorobenzene and p-fluorobenzoyl chloride is (1-4):1; the solid acid catalyst is selected from at least one of phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, perfluorosulfonic acid resin, and a strong acidic cation exchange resin with sulfonic acid groups on a styrene-diethylene copolymer; the amount of the solid acid catalyst is 5-10% of the total mass of fluorobenzene.

[0010] Preferably, the molar ratio of fluorobenzene to p-fluorobenzoyl chloride is 1.5-2.5:1. In the reaction process, fluorobenzene acts as both a reactant and a solvent; therefore, a molar ratio of 1.5-2.5:1 is suitable. A lower molar ratio results in a higher viscosity of the reaction system and incomplete reaction; a higher molar ratio leads to waste of fluorobenzene and increased energy consumption. Using a supported solid acid as a catalyst avoids the large-scale use of strong acids such as concentrated sulfuric acid and aluminum trichloride in traditional processes, significantly improving the environmental friendliness of the process. Furthermore, the supported solid acid catalyst can be reused multiple times, increasing catalyst efficiency.

[0011] Preferably, the solid acid catalyst is a strong acid cation exchange resin with sulfonic acid groups on a styrene-diethylene copolymer, which appears as yellowish-brown transparent spherical particles and is used in an amount of 6-8% of the mass of fluorobenzene.

[0012] Preferably, the reaction equation for 4,4'-difluorobenzophenone in step (1) is as follows:

[0013]

[0014] Further, the fluorinated monomer in step (2) is 2,6-difluorobenzonitrile, and the amount added is 0-100% of the mass of 4,4'-difluorobenzophenone; the bisphenol compound is selected from at least one of hydroquinone, bisphenol A, 4,4'-dihydroxydiphenyl ether, phenolphthalein, and 4,4'-dihydroxydiphenyl sulfone.

[0015] Preferably, the amount of 2,6-difluorobenzonitrile added in step (2) is 30-80% of the mass of 4,4'-difluorobenzophenone; the introduction of rigid nitrile groups can, on the one hand, enhance the polarity of the molecular chain and improve the compatibility with materials such as carbon fiber and glass fiber; on the other hand, the nitrile groups are located on the molecular side chain, which can effectively adjust the crystallinity of the resin and reduce the melt viscosity, which is beneficial to the processing and molding of the material.

[0016] Preferably, the low-cost, high-performance polyaryletherketone (nitrile) prepared by the present invention has low crystallinity. Bisphenol monomers such as phenol and bisphenol A with large side chain steric hindrance groups can be preferentially selected for reaction. Through the combined action of nitrile groups and large side chain steric hindrance groups, the crystallinity and crystal morphology of polyaryletherketone (nitrile) materials can be precisely controlled.

[0017] Further, the total molar ratio of the sum of the 4,4'-difluorobenzophenone and the fluorinated monomers in step (2) to the molar ratio of the bisphenol compound is 1:(0.9-1.5).

[0018] Further, the solvent in step (2) is selected from at least one of dimethyl sulfoxide, N-methylpyrrolidone, and sulfolane; the alkali metal carbonate is a mixture of potassium carbonate and sodium carbonate, wherein the mass ratio of potassium carbonate to sodium carbonate is (2-20):1; and the total molar amount of potassium carbonate and sodium carbonate is in the molar ratio of the bisphenol compound to the total molar amount of the bisphenol compound is (1-1.5):1.

[0019] Preferably, the alkali metal carbonate in step (2) is a mixture of potassium carbonate and sodium carbonate, wherein the mass ratio of potassium carbonate to sodium carbonate is (10-15):1; and the molar ratio of the total molar amount of potassium carbonate and sodium carbonate to the molar amount of bisphenol compounds is (1.02-1.1):1. In fact, potassium carbonate (K2CO3) has higher reactivity than sodium carbonate (Na2CO3) and is more effective at forming salts with bisphenol compounds. When potassium carbonate is used alone, the reaction rate is fast, and a higher molecular weight can be obtained in a short time, but the molecular weight distribution of the product is wider; while sodium carbonate has relatively mild reactivity, and the molecular weight of the polymer increases slowly when used alone. Therefore, the ratio of the two can be reasonably adjusted according to the target reaction rate; in addition, as the amount of alkali metal carbonate increases, the molecular weight of the product will gradually increase, but the molecular weight distribution will also become wider. The reason is that increasing the amount of alkali metal will accelerate the polymerization reaction rate, and the molecular weight of the polymer formed in the early stage is relatively high, making it easy to precipitate prematurely from the solvent, ultimately leading to a wider molecular weight distribution.

[0020] Preferably, the reaction equation for the polyaryletherketone (nitrile) resin in step (2) is as follows (using phenolphthalein as an example for bisphenol compounds):

[0021]

[0022] Further, the reaction temperature in step (1) is 60-80℃, and the reaction time is 4-8h; the stepwise distillation includes: first, atmospheric distillation at 120-155℃ to recover fluorobenzene, and then vacuum distillation at 190-220℃ to obtain pure 4,4'-difluorobenzophenone. The fluorobenzene that did not participate in the reaction can be recovered and reused by atmospheric distillation; the product 4,4'-difluorobenzophenone can be obtained by vacuum distillation, and the purity of the product after one distillation can reach more than 99%. The remaining impurities are mostly isomers of 4,4'-difluorobenzophenone, such as 2,4'-difluorobenzophenone, etc.; these impurities have no effect on the preparation of low-crystallinity polyarylether ketones (nitriles). If it is necessary to obtain high-crystallinity resins, such as PEEK materials, the purity of 4,4'-difluorobenzophenone needs to be further improved.

[0023] Further, in step (2), the staged heating includes: first holding the reaction at 140-160℃ for 1-3 hours, then heating to 180-200℃ for 1-3 hours for prepolymerization, and finally heating to 200-250℃ for 2-4 hours for holding the reaction; the inert atmosphere is an argon atmosphere.

[0024] Further, the pulverization mesh size in step (3) is 80-200 mesh; the washing is 3-6 times with water and 2-4 times with ethanol; the drying conditions are 40-100℃ for 12-48h.

[0025] Preferably, the preparation method of the low-cost, high-performance polyaryletherketone (nitrile) resin of the present invention includes the following steps:

[0026] (1) Low-cost synthesis and purification of 4,4'-difluorobenzophenone

[0027] Starting with fluorobenzene and p-fluorobenzoyl chloride, the mixture is fed into a fixed-bed reactor under the action of a solid acid catalyst. The reactor is circulated at 60–80 °C for 4–8 hours, yielding a mixture of fluorobenzene and 4,4-difluorobenzophenone. This mixture is then distilled at atmospheric pressure at 120–155 °C. The distilled product is fluorobenzene, which can be recycled. The remaining substrate is then distilled under reduced pressure at 190–220 °C to obtain 4,4'-difluorobenzophenone product with a purity of over 99%, which is then reserved for use.

[0028] (2) Polycondensation reaction: Add self-made 4,4'-difluorobenzophenone, other fluorinated monomers and bisphenol compounds, the appropriate amount of alkali metal carbonate and appropriate amount of solvent to a three-necked flask equipped with mechanical stirring. Under the protection of light and argon atmosphere, heat to 140-160℃ and keep warm for 1-3h. Then heat to 180-200℃ for prepolymerization for 1-3h. Finally heat to 200-250℃ and keep warm for 2-4h for polymerization reaction. After the reaction is completed, discharge the high temperature reaction product (crude resin) into a room temperature water bath through a pipeline to cool and solidify.

[0029] (3) Post-processing: The obtained crude resin is crushed, washed, dried and other steps to obtain a low-cost, high-performance polyarylether ketone (nitrile) resin product.

[0030] The low-cost, high-performance polyaryletherketone (nitrile) resin prepared by the method described in this invention is a low-cost, high-performance polyaryletherketone (nitrile) resin.

[0031] The present invention relates to the application of low-cost, high-performance polyaryletherketone (nitrile) resin in high-end pipes, 3D printing, special engineering plastics, electronics and electrical engineering, aerospace and automotive lightweighting.

[0032] The key design principle of this invention is the self-production of a low-cost 4,4-difluorobenzophenone. This technology features a simple production process, reusable catalysts, and reduces the need for large amounts of concentrated sulfuric acid or aluminum trichloride in traditional processes, significantly improving environmental performance. Furthermore, the post-processing is simple and efficient. The prepared 4,4-difluorobenzophenone can be used as a monomer to directly prepare low-cost, high-performance polyaryletherketone (nitrile) resins. Simultaneously, the crystallinity and viscosity of the prepared polyaryletherketone (nitrile) resin can be precisely controlled through molecular structure adjustments, achieving a processing efficiency 2–4 times that of PEEK materials in fields such as pipe manufacturing and 3D printing, effectively improving production efficiency and economic benefits.

[0033] Strong acidic cation exchange resins with sulfonic acid groups on styrene-diethylene copolymers are supported solid acids. They exist in solid form at room temperature and reaction temperature and do not enter the reaction product system after the reaction, so they can be recycled and reused. In contrast, catalysts such as trifluoromethanesulfonic acid, N,N-dimethyl-4-pyridinium amine, and fluorobenzenesulfonic acid exist in liquid or powder form. After the reaction, they enter the reaction product system, require separation, and cannot be reused.

[0034] Compared with existing technologies, the self-made 4,4'-difluorobenzophenone has the following advantages: ① The catalyst can be recycled and reused, effectively reducing production costs. ② The reaction process avoids the large-scale use of strong acid reagents such as concentrated sulfuric acid and aluminum trichloride in traditional processes, significantly improving the environmental friendliness of the process. ③ Compared with traditional processes, the post-processing flow is simple. The prepared product does not need to undergo a separation process from the catalyst. The product only needs to be distilled in one step using a vacuum distillation process to obtain 4,4'-difluorobenzophenone with a purity of over 99%. This greatly simplifies the post-processing flow of 4,4'-difluorobenzophenone monomer, significantly reducing production costs while significantly reducing the emission of volatile organic compounds (VOCs) generated by traditional purification processes, and reducing the difficulty of post-processing.

[0035] Furthermore, the high cost of specialty polymer materials such as PEEK is due not only to significant technological barriers and complex production processes, but also to the high cost of raw materials. Among these, the cost of 4,4'-difluorobenzophenone (DFBP) is particularly prominent – ​​approximately 0.7-0.8 tons of fluoroketone monomer are consumed for every ton of PEEK produced, accounting for over 50% of the raw material cost and significantly impacting the overall cost of PEEK. Therefore, this invention utilizes self-made, low-cost 4,4-difluorobenzophenone to significantly reduce the production cost of polyarylether ketone (nitrile) resins while ensuring a stable supply of raw materials and maintaining material performance.

[0036] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages:

[0037] (1) The present invention uses a strong acid cation exchange resin with sulfonic acid groups on a solid acid styrene-diethylene copolymer as a catalyst to prepare 4,4'-difluorobenzophenone. The catalyst can be recycled and reused, effectively reducing production costs. At the same time, it avoids the use of large amounts of strong acid reagents such as concentrated sulfuric acid and aluminum trichloride in traditional processes, significantly improving the environmental friendliness of the process.

[0038] (2) The present invention obtains 4,4'-difluorobenzophenone product with a purity of over 99% by one-step distillation through vacuum distillation process, which greatly simplifies the post-processing process of 4,4'-difluorobenzophenone monomer, reduces production costs, significantly reduces the emission of volatile organic compounds (VOCs) generated by traditional purification processes, and reduces the difficulty of post-processing.

[0039] (3) By introducing nitrile groups and large side chain steric hindrance groups, the crystallinity and crystal morphology of polyaryletherketone (nitrile) materials can be precisely controlled, so that the crystallinity of the resin is significantly reduced without significant loss of mechanical properties.

[0040] (4) The present invention uses 4,4'-difluorobenzophenone obtained by single distillation directly for polymerization to prepare polyarylether ketone (nitrile) resin. While ensuring a stable supply of raw materials and material properties, it significantly reduces production costs. This low-cost process route is particularly suitable for the preparation of polyarylether ketone (nitrile) with low crystallinity. If high crystallinity resin is required, it is only necessary to further improve the purity of 4,4'-difluorobenzophenone.

[0041] (5) The polyaryletherketone (nitrile) resin prepared by the present invention can achieve a processing efficiency of 2-4 times that of PEEK material in fields such as pipelines and 3D printing by precise control of crystallinity, effectively improving production efficiency and economic benefits.

[0042] (6) The polyaryletherketone (nitrile) resin prepared by this invention has excellent mechanical properties, simple preparation process, green and environmentally friendly and low cost. It can be widely used in high-end pipes, 3D printing, special engineering plastics, electronics and electrical, aerospace and automotive lightweighting and other fields, and has broad market application prospects and economic value. Attached Figure Description

[0043] Figure 1 The 1H NMR spectrum of 4,4'-difluorobenzophenone prepared in this invention;

[0044] Figure 2 The carbon NMR spectrum of 4,4'-difluorobenzophenone prepared in this invention;

[0045] Figure 3 This is the DSC curve for Example 1.

[0046] Figure 4 HPLC analysis of 4,4-difluorobenzophenone prepared in Example 1;

[0047] Figure 5 HPLC analysis of commercially available 4,4'-difluorobenzophenone;

[0048] Figure 6 Infrared spectra of Example 1 and Comparative Example 1; Detailed Implementation

[0049] The technical solution of the present invention will be further described below with reference to the accompanying drawings.

[0050] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0051] Among them, the strong acidic cation exchange resin with sulfonic acid groups on the styrene-diethylene copolymer was purchased from Ningbo Zhengguang Resin Co., Ltd., model CD022A; the commercially available 4,4'-difluorobenzophenone (purity above 99.8%) was purchased from Jiangsu Xinhan New Material Co., Ltd., batch number 20250801; the PEEK resin was purchased from Zhejiang Pengfulong Technology Co., Ltd., model 8200G; the PES resin was purchased from Solvay, model VW-10200; the fixed bed reactor was purchased from Kunshan Qingxu Environmental Technology Co., Ltd., model: QXQ111; and the second-grade 4,4'-difluorobenzophenone (purity below 98%) was purchased from Shanghai Renhe New Material Technology Co., Ltd.

[0052] In the following embodiments:

[0053] As a preferred option, an evaluation standard for low-cost, high-performance polyaryletherketone (nitrile) resin includes purity analysis of 4,4'-difluorobenzophenone and performance analysis of the polyaryletherketone (nitrile) resin.

[0054] High-performance liquid chromatography (HPLC): A high-performance liquid chromatograph equipped with a C18 reversed-phase column and a UV detector was used. Gradient elution was performed using a chromatographic grade (or acetonitrile / water) system as the mobile phase. This was used to characterize the conversion rate of the synthesis reaction and the chemical purity of the final monomer product. The purity of the target monomer was calculated by comparing the retention times of the reaction substrate and the target product on the chromatographic column and by using peak area normalization.

[0055] Infrared spectroscopy analysis: A Thermo Scientific Nicolet iS10 Fourier transform infrared spectrometer was used. Samples were prepared using the KBr pellet method, and the spectra were analyzed in the range of 400-4000 cm⁻¹. -1 Infrared spectroscopy was performed on the sample within the wavenumber range.

[0056] DSC test: A TA DSC Q2000 differential scanning calorimeter was used to conduct tests in a nitrogen atmosphere at a heating and cooling rate of 10 °C·min⁻¹ within the range of 100–480 °C.

[0057] Molecular weight determination: Gel permeation chromatography (GPC) was used with tetrahydrofuran (THF) as the mobile phase at a flow rate of 1.0 mL / min and a column temperature of 40 ℃. The molecular weight and distribution of the samples were determined by differential refractive index detector.

[0058] Mechanical property testing: The tensile strength and elongation at break of polyaryletherketone (nitrile) resin were tested using a universal tensile testing machine in accordance with ISO 527 standard, and the flexural strength and flexural modulus of polyaryletherketone (nitrile) resin were tested in accordance with ISO 178 standard.

[0059] To further illustrate the present invention, the present invention will be further described below with reference to specific embodiments.

[0060] Example 1

[0061] (1) Low-cost synthesis and purification of 4,4'-difluorobenzophenone: 200g of fluorobenzene (2.08mol) and 158g of p-fluorobenzoyl chloride (1mol) were mixed and fed into a fixed-bed reactor under the action of a strong acidic cation exchange resin with sulfonic acid groups on 12g of styrene-diethylene copolymer. The mixture was circulated at 60℃ for 6h, and the product was a mixture of fluorobenzene and 4,4-difluorobenzophenone. The mixture was distilled at atmospheric pressure at 140℃. The product obtained by distillation was fluorobenzene, which could be recycled. The remaining substrate was distilled under reduced pressure at 200℃ and -0.09MPa to obtain 4,4'-difluorobenzophenone product.

[0062] (2) Polycondensation reaction: 218g of 4,4'-difluorobenzophenone (1mol), 65.4g of 2,6-difluorobenzonitrile (0.3mol), 413g of phenolphthalein (1.3mol), 165.6g of K2CO3 (1.2mol), 8.5g of Na2CO3 (0.08mol) and 1800g of sulfolane prepared in step (1) were added to a three-necked flask equipped with mechanical stirring. Under the protection of light and argon atmosphere, the stirring speed was controlled at 300 r / min, the temperature was raised to 150℃ and kept at that temperature for 1h; then the temperature was raised to 180℃ for prepolymerization reaction for 2h; finally the temperature was raised to 230℃ and kept at that temperature for 3h for polymerization reaction. After the reaction was completed, the high temperature reaction product (crude resin) was discharged into a room temperature water bath through a pipeline to cool and solidify, and crude polyaryletherketone (nitrile) resin was obtained.

[0063] (3) Post-processing: The obtained crude resin is crushed to a mesh size of 80-200; then washed with water 6 times and ethanol 2 times; and dried at 80℃ for 12h to obtain a low-cost, high-performance polyaryletherketone (nitrile) resin product.

[0064] See Figure 1 and Figure 2 Analysis revealed that the ¹³C NMR spectrum of 4,4'-difluorobenzophenone showed a characteristic carbonyl signal of the ketone group at 180–190 ppm, while characteristic peaks of aromatic carbons in different chemical environments on the fluorobenzene ring were observed in the 110–160 ppm region. The corresponding ¹H NMR spectrum showed two sets of symmetrically distributed multiple peaks in the aromatic hydrogen region at 7–8 ppm, corresponding to two types of hydrogen atoms on the benzene ring near the carbonyl group and the fluorine substituent, respectively. This perfectly matched the structural characteristics of the target molecule, confirming the successful synthesis of the compound.

[0065] See Figure 3 As shown in the DSC curve, a distinct endothermic peak appears at 200℃, which is the glass transition temperature (Tg) of the polyaryletherketone (nitrile) resin, characteristic of the material's transition from a glassy state to a rubbery state. Simultaneously, the curve shows no obvious melting endothermic peak between 50 and 200℃, indicating that the sample has extremely low crystallinity, is essentially amorphous, with disordered molecular chains and no regular crystalline regions. No drastic thermal effect was observed even at around 350℃, indicating a high thermal decomposition temperature and good thermal stability within this temperature range. In summary, this polyaryletherketone (nitrile) resin is an amorphous polymer with a Tg of approximately 200℃, low crystallinity, and is not easily decomposed at high temperatures, exhibiting good heat resistance and processing stability.

[0066] Example 2

[0067] Example 2 is the same as Example 1 in preparing low-cost, high-performance polyaryletherketone (nitrile) resin. The difference is that in step (2), 22g of hydroquinone (0.2mol) is added, the amount of K2CO3 added is 179.4g (1.3mol), the amount of Na2CO3 added is 9.5g (0.09mol), and sulfolane is replaced with 2000g of diphenyl sulfone; the polymerization reaction temperature is 250℃, and the heat preservation reaction time is 4h; in step (3), toluene is washed 3 times, water is washed 3 times, and ethanol is washed 2 times.

[0068] Example 3

[0069] Example 3 is the same as Example 1 in the method of preparing low-cost, high-performance polyaryletherketone (nitrile) resin products. The difference is that in step (1), the strong acid cation exchange resin with sulfonic acid groups on the styrene-diethylene copolymer is replaced with 10g of phosphotungstic acid, and the reaction is carried out at 70°C for 6h. The remaining substrate is distilled at 210°C and -0.09MPa under reduced pressure.

[0070] Example 4

[0071] Example 4 is the same as Example 2 in preparing low-cost, high-performance polyaryletherketone (nitrile) resin products. The difference is that in step (1), the strong acidic cation exchange resin with sulfonic acid groups on the styrene-diethylene copolymer is replaced with 10g of phosphotungstic acid, and the reaction is carried out at 70°C for 6h. The remaining substrate is distilled at 200°C and -0.09MPa under reduced pressure.

[0072] Comparative Example 1

[0073] The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin products in Comparative Example 1 is the same as that in Example 1, except that step (1) is omitted and commercially available 4,4'-difluorobenzophenone (purity above 99.8%) is used in step (2) for polycondensation reaction.

[0074] Comparative Example 2

[0075] The method for preparing low-cost, high-performance polyarylether ketone (nitrile) resin products in Comparative Example 1 is the same as that in Example 1, except that in step (2), condensation reaction is carried out using commercially available second-grade 4,4'-difluorobenzophenone (purity below 98%).

[0076] Comparative Example 3

[0077] Commercially available PEEK resin.

[0078] Comparative Example 4

[0079] Commercially available PES resin.

[0080] Performance testing

[0081] The commercially available 4,4-difluorobenzophenone used in Example 1 and Comparative Example 1 was analyzed by HPLC. See [link to relevant documentation]. Figure 4-5 As shown in the figures, the purity of 4,4-difluorobenzophenone obtained in Example 1 is 99.05%, while the purity of commercially available 4,4-difluorobenzophenone is 99.91%.

[0082] See Figure 6 The low-cost, high-performance polyaryletherketone (nitrile) resins prepared in Example 1 and Comparative Example 1 were analyzed by infrared spectroscopy, and the results are as follows: Figure 5 As shown, 2200cm -1 The area near the -CN characteristic absorption peak is at 1750 cm⁻¹. -1 The nearby peak is the carbonyl characteristic peak on the lactone of the phenolphthalein structural unit, at 1650 cm⁻¹. -1 The peak near the image represents the stretching vibration of the carbonyl group in 4,4-difluorobenzophenone. A comparison shows that there is no significant difference in the characteristic absorption peaks of Example 1 and Comparative Example 1, indicating that their chemical structures are basically the same.

[0083] The molecular weight and mechanical properties of eight resins from Examples 1-4 and Comparative Examples 1-4 were tested, and the results are shown in Table 1. The pipes were manufactured using extrusion molding at a traction temperature of 300-330℃ (400℃ for PEEK). After molding, the pipes underwent slow cooling under low stress and annealing to stabilize the pipe dimensions, eliminate internal stress, and ensure the product's mechanical properties and operational stability. Specific test results are shown in Table 1.

[0084] Table 1 Comparison of basic properties of resins

[0085]

[0086] As can be seen from the comparison, the resins prepared in Examples 1-4 and Comparative Example 1 showed no significant differences in molecular weight, molecular weight distribution, tensile strength, and flexural modulus, indicating that the self-made low-cost 4,4'-difluorobenzophenone had no significant impact on the resin synthesis process. In terms of mechanical and thermal properties, the tensile strength (101 MPa), flexural modulus (2.8 GPa), and glass transition temperature (201 °C) of Example 1 were better than or equal to those of the other examples, and the pipe processing speed reached 4.0 m / min, demonstrating outstanding comprehensive performance. In comparison, the tensile strength and flexural modulus of Examples 2 and 4 were slightly lower, and the processing speed of Example 3 was slightly slower. Compared with Comparative Example 2, the resin obtained from commercially available second-grade 4,4'-difluorobenzophenone (purity below 98%) had a molecular weight of only about 8000 and could not be processed, possibly because 4,4'-difluorobenzophenone had too many impurities and was difficult to participate in the reaction. At the same time, compared with the conventional PEEK product of Comparative Example 3, the glass transition temperature of this resin was significantly increased. Moreover, through crystallinity optimization, its processing rate was 2-4 times higher than that of PEEK, which can greatly improve the resin production efficiency.

[0087] In summary, the low-cost, high-performance polyarylether ketone (nitrile) resin product prepared from 4,4'-difluorobenzophenone using a strongly acidic cation exchange resin with sulfonic acid groups on a styrene-diethylene copolymer in Example 1 achieves the best balance between molecular weight distribution, mechanical properties, heat resistance, and processing efficiency, resulting in optimal overall performance.

[0088] The resins from Examples 1-4, Comparative Examples 1 and 3 were used as toughening resins to modify epoxy resin / cyanate ester resin systems (the PES powder in Comparative Example 3 is a high-end product of current toughening resins). The epoxy resin selected was Nan Ya NPEL-128 epoxy resin, and the cyanate ester resin was dicyandiamide. The mass ratio of epoxy resin to dicyandiamide was 100:7 (epoxy equivalent: active hydrogen equivalent = 1:1). The curing conditions were: curing at 150℃ for 4 hours, followed by curing at 200℃ for 2 hours. The amount of toughening resin added was 15% of the epoxy resin. The test results are shown in Table 2.

[0089] Table 2 Comparison of basic properties of resins

[0090]

[0091] As shown in Table 2, compared with PES resin, the polyaryletherketone (nitrile) resin prepared in this invention exhibits superior mechanical properties, including tensile strength, tensile modulus, elongation at break, and flexural strength, when used to toughen and modify epoxy resin / cyanate ester resin systems. Furthermore, this resin costs only half that of PES resin, and its preparation method is simple, demonstrating significant cost-effectiveness advantages and broad market application prospects.

[0092] In summary, this invention has prepared a batch of high-performance polyarylether ketone (nitrile) resins by using self-made, low-cost 4,4-difluorobenzophenone. Without affecting the mechanical properties of the resin, it significantly reduces production costs and improves ease of use. The polyarylether ketone (nitrile) resins prepared by this invention have excellent mechanical properties, a simple preparation process, are environmentally friendly, and are low in cost. They can be widely used in high-end pipes, 3D printing, special engineering plastics, electronics, aerospace, and automotive lightweighting, and have broad market application prospects and economic value.

Claims

1. A method for preparing a low-cost, high-performance polyaryletherketone (nitrile) resin, characterized in that, Includes the following steps: (1) Synthesis and purification of low-cost 4,4'-difluorobenzophenone: fluorobenzene and p-fluorobenzoyl chloride were used as starting materials and reacted under the action of solid acid catalyst. The resulting reaction mixture was separated by stepwise distillation under different temperature conditions. The fluorobenzene was recovered and high-purity 4,4'-difluorobenzophenone was obtained. (2) Polycondensation reaction: Under inert gas protection and light-proof conditions, 4,4'-difluorobenzophenone, fluorinated monomers and bisphenol compounds, alkali metal carbonates and solvents prepared in step (1) are mixed and polymerized by heating in stages. After the reaction is completed, the product is cooled and solidified to obtain crude polyarylether ketone (nitrile) resin. (3) Post-processing: The polyaryletherketone (nitrile) resin is crushed, washed and dried to obtain a low-cost, high-performance polyaryletherketone (nitrile) resin product.

2. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The molar ratio of fluorobenzene and p-fluorobenzoyl chloride in step (1) is (1-4):1; the solid acid catalyst is selected from at least one of phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, perfluorosulfonic acid resin, and strong acidic cation exchange resin with sulfonic acid groups on styrene-diethylene copolymer; the amount of solid acid catalyst is 5-10% of the total mass of fluorobenzene.

3. The low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The fluorinated monomer in step (2) is 2,6-difluorobenzonitrile, and the amount added is 0-100% of the mass of 4,4'-difluorobenzophenone; the bisphenol compound is selected from at least one of hydroquinone, bisphenol A, 4,4'-dihydroxydiphenyl ether, phenolphthalein, and 4,4'-dihydroxydiphenyl sulfone.

4. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The total molar ratio of the sum of the 4,4'-difluorobenzophenone and the fluorinated monomers in step (2) to the molar ratio of the bisphenol compound is 1:(0.9-1.5).

5. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The solvent in step (2) is selected from at least one of dimethyl sulfoxide, N-methylpyrrolidone, and sulfolane; the alkali metal carbonate is a mixture of potassium carbonate and sodium carbonate, wherein the mass ratio of potassium carbonate to sodium carbonate is (2-20):1; the total molar amount of potassium carbonate and sodium carbonate is in the molar ratio of the bisphenol compound to (1-1.5):

1.

6. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The reaction temperature in step (1) is 60-80℃ and the reaction time is 4-8h; the stepwise distillation includes: first, distilling at atmospheric pressure at 120-155℃ to recover fluorobenzene, and then distilling under reduced pressure at 190-220℃ to obtain pure 4,4'-difluorobenzophenone.

7. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, In step (2), the staged heating includes: first, holding the reaction at 140-160℃ for 1-3 hours, then heating to 180-200℃ for 1-3 hours for prepolymerization, and finally heating to 200-250℃ for 2-4 hours for holding the reaction; the inert atmosphere is an argon atmosphere.

8. The method for preparing low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1, characterized in that, The pulverization mesh size in step (3) is 80-200 mesh; the washing is 3-6 times with water and 2-4 times with ethanol; the drying conditions are 40-100℃ for 12-48 hours.

9. A low-cost, high-performance polyaryletherketone (nitrile) resin prepared by the method for preparing the low-cost, high-performance polyaryletherketone (nitrile) resin according to claim 1.

10. The application of the low-cost, high-performance polyaryletherketone (nitrile) resin of claim 9 in the fields of high-end pipes, 3D printing, special engineering plastics, electronics and electrical engineering, aerospace and automotive lightweighting.

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