Low-expansion-coefficient polyaryletherketone and preparation method thereof
By introducing rigid groups into the molecular chain, polyaryletherketones with low expansion coefficients were prepared, solving the problem of large dimensional changes in PEEK materials at high temperatures and achieving dimensional stability of high-precision gears.
Patent Information
- Application Number
- CN202511117675.9
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-08-11
- Publication Date
- 2025-11-11
AI Technical Summary
The existing PEEK material has a large coefficient of thermal expansion, which leads to large changes in the size of PEEK gears at high temperatures, affecting the normal operation of the machine.
By introducing rigid groups into the molecular chain, the steric hindrance of the molecular weight is increased, and polyarylether ketones with low expansion coefficient are prepared, thereby reducing the linear expansion coefficient of the material.
The linear expansion coefficient of PEEK material was reduced to less than 48ppm/K in the range of 10-110℃, which improved the dimensional stability of the material and prevented gear jamming at high temperatures.
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Figure CN120923766A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of polyaryl ether ketone technology, specifically to a polyaryl ether ketone with a low coefficient of thermal expansion and its preparation method. Background Technology
[0002] Polyaryletherketone (PAEK) is a class of high-performance thermoplastic engineering plastics composed of alternating aromatic rings, ether bonds, and ketone bonds. It possesses excellent properties such as high temperature resistance, chemical corrosion resistance, high strength, and flame retardancy. Representative varieties include polyetheretherketone (PEEK), polyetherketone (PEK), and polyetherketoneketone (PEKK), with PEEK being the most widely used. Its long-term operating temperature can reach 260℃, and its instantaneous temperature resistance can reach 300℃. PAEK has high molecular chain rigidity and strong crystallinity, combining thermoplasticity and mechanical stability, making it suitable for various processing methods such as injection molding and extrusion. PAEK is widely used in aerospace, medical devices, the automotive industry, and electronics, such as in aircraft parts, artificial bone implants, and high-temperature resistant cables.
[0003] For some complex PAEK products with stringent precision requirements, such as PEEK gears used in micro liquid metering pumps, the PEEK material needs to exhibit high dimensional stability at different temperatures. However, in actual use, PEEK gears often experience significant dimensional changes as the liquid temperature (10-110℃) rises. This ultimately leads to the PEEK gears functioning normally at room temperature, but jamming when the liquid temperature rises above 60℃, thus affecting the normal operation of the machine at high temperatures.
[0004] The relatively large coefficient of thermal expansion of existing PEEK materials limits their application in gears requiring high precision. Summary of the Invention
[0005] To address the aforementioned technical problems, this invention provides a polyaryl ether ketone with a low coefficient of thermal expansion and its preparation method. This invention introduces rigid groups into the molecular chain through front-end polymerization, thereby mitigating the movement of the molecular side chains by increasing steric hindrance, thus improving the dimensional stability of PAEK gears during heating and ensuring normal operation of the gears in the high-temperature range.
[0006] To achieve the above objectives, the present invention is implemented through the following technical solution:
[0007] A method for preparing a polyaryl ether ketone with a low coefficient of thermal expansion includes the following steps:
[0008] In a protective atmosphere, difluorobenzophenone and hydroquinone compounds undergo a salt formation reaction in the presence of carbonates and reaction solvents, followed by a polycondensation reaction at elevated temperature to obtain polyaryl ether ketone prepolymers.
[0009] The quinone compounds mentioned above are selected from one or more of resorcinol, hydroquinone, phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol;
[0010] The molar ratio of the difluorobenzophenone to the hydroquinone compound is 1-1.1:1.
[0011] Further, the quinone compounds are selected from the first combination or the second combination, wherein the first combination is a combination of one or more of resorcinol and hydroquinone with one or more of phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol, and the second combination is one or more of phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol;
[0012] In the first combination, the molar percentage of one or more of the resorcinol and hydroquinone is less than or equal to 50%.
[0013] Furthermore, the carbonate is selected from sodium carbonate and / or potassium carbonate, the powder particle size is less than 200 mesh, and the amount of the carbonate used is 1-2 times the total molar amount of the difluorobenzophenone and the hydroquinone compound;
[0014] The reaction solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide. Toluene, an azeotropic agent, is added to the reaction system. The amount of the reaction solvent is 4-6 times the total molar amount of the difluorobenzophenone and the hydroquinone compounds, and the amount of the azeotropic agent is 10-20% of the mass of the reaction solvent.
[0015] Furthermore, the salt formation reaction is carried out at a temperature of 140-160℃ and for a reaction time of 1-5 hours.
[0016] Furthermore, the polycondensation reaction is carried out at a temperature of 180-205°C for a reaction time of 3-8 hours.
[0017] Furthermore, after the polycondensation reaction is completed, the process also includes adding a poor solvent to the reaction system to precipitate, wash, and dry the product; the poor solvent is an alcohol solvent and / or water.
[0018] In another aspect, the present invention provides a polyarylether ketone with a low coefficient of thermal expansion obtained by the above preparation method, wherein the linear coefficient of thermal expansion at 10-110°C is less than 48 ppm / K.
[0019] Beneficial technical effects:
[0020] This invention introduces functional groups with high rigidity and steric hindrance into the molecular chain through front-end polymerization, which greatly improves the dimensional stability of PEEK materials, reducing the linear expansion coefficient of the product from the original 52ppm / K to below 48ppm / K. The PEEK material with high dimensional stability of this invention is mainly used in high-precision gears and other scenarios with high requirements for product dimensional stability. Attached Figure Description
[0021] Figure 1 The linear expansion coefficient curve of conventional PEEK in Comparative Example 1 (Formula 1);
[0022] Figure 2 The linear expansion coefficient curve of PAEK with phenyl side chain in Example 1 (Formula 2) is shown.
[0023] Figure 3 The linear expansion coefficient curve of PAEK with phenyl side chain in Example 2 (Formula 3);
[0024] Figure 4 The linear expansion coefficient curve of PAEK with phenyl side chain in Example 3 (Formula 4) is shown.
[0025] Figure 5 The linear expansion coefficient curve of PAEK with phenyl side chain in Example 4 (Formula 5);
[0026] Figure 6 A photograph of a gear made using PAEK with phenyl side chains as described in Example 4;
[0027] Figures 1 to 5 The vertical axis in the graph is dL / L0, representing the relative rate of change of the sample length. Points on the curve represent the ratio of the total change in sample length at that temperature to the initial length at room temperature, i.e., (L... T -L0) / L0, and thus a curve drawn with temperature as the abscissa is the curve dL / L0. Detailed Implementation
[0028] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments and accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.
[0029] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that values expressed, for example, as "within the range of ab" or "between the range of ab," do not include the endpoint values a and b; values expressed as "for ab," "is ab," or "ab" include the endpoint values a and b.
[0030] Experimental methods not specified in the following examples are generally performed according to national standards; if there is no corresponding national standard, they are performed according to general standard requirements or general methods.
[0031] Comparative Example 1
[0032] This case study demonstrates the synthesis of standard PEEK:
[0033] Under N2 protection, the materials were added sequentially to a three-necked flask equipped with a mechanical stirrer according to Formula 1 in Table 1. The temperature was raised to 140°C and toluene (the amount of toluene was 15% of the weight of the reaction solvent) was added. An azeotropic dehydration salt formation reaction was carried out for 2 hours. Then, the temperature was raised to 195°C and a polycondensation reaction was carried out for 6 hours. The temperature was lowered to below 60°C and the product was poured into anhydrous ethanol to precipitate the product. The product was washed 6 times with distilled water and finally dried under vacuum at 100°C for 48 hours to obtain conventional PEEK coarse powder.
[0034] Example 1
[0035] This case study involves the synthesis of PAEK with a low coefficient of thermal expansion.
[0036] Under N2 protection, the materials were added sequentially to a three-necked flask equipped with a mechanical stirrer according to formulation 2 in Table 1. The temperature was raised to 140°C and toluene (the amount of toluene was 15% of the weight of the reaction solvent) was added. An azeotropic dehydration salt formation reaction was carried out for 2 hours. Then, the temperature was raised to 195°C and a polycondensation reaction was carried out for 6 hours. The temperature was lowered to below 60°C and the product was poured into anhydrous ethanol to precipitate the product. The product was washed 6 times with distilled water and finally dried under vacuum at 100°C for 48 hours to obtain PAEK crude powder with a phenyl group in the inner side chain of the repeating unit.
[0037] Example 2
[0038] This case study involves the synthesis of PAEK with a low coefficient of thermal expansion.
[0039] Under N2 protection, the materials were added sequentially to a three-necked flask equipped with a mechanical stirrer according to formulation 3 in Table 1. The temperature was raised to 140°C and toluene (the amount of toluene was 15% of the weight of the reaction solvent) was added. An azeotropic dehydration salt formation reaction was carried out for 2 hours. Then, the temperature was raised to 195°C and a polycondensation reaction was carried out for 6 hours. The temperature was lowered to below 60°C and the product was poured into anhydrous ethanol to precipitate the product. The product was washed 6 times with distilled water and finally dried under vacuum at 100°C for 48 hours to obtain PAEK crude powder with two phenyl groups in the inner side chain of the repeating unit.
[0040] Example 3
[0041] This case study involves the synthesis of PAEK with a low coefficient of thermal expansion.
[0042] Under N2 protection, the materials were added sequentially to a three-necked flask with mechanical stirring according to formulation 4 in Table 1. The temperature was raised to 140°C and toluene (the amount of toluene was 15% of the weight of the reaction solvent) was added. An azeotropic dehydration salt formation reaction was carried out for 2 hours. Then, the temperature was raised to 195°C and a polycondensation reaction was carried out for 6 hours. The temperature was lowered to below 60°C and the product was poured into anhydrous ethanol to precipitate the product. The product was washed 6 times with distilled water and finally dried under vacuum at 100°C for 48 hours to obtain PAEK crude powder with a phenyl side chain in the repeating unit.
[0043] Example 4
[0044] This case study involves the synthesis of PAEK with a low coefficient of thermal expansion.
[0045] Under N2 protection, the materials were added sequentially to a three-necked flask equipped with a mechanical stirrer according to formulation 5 in Table 1. The temperature was raised to 140°C and toluene (the amount of toluene was 15% of the weight of the reaction solvent) was added. An azeotropic dehydration salt formation reaction was carried out for 2 hours. Then, the temperature was raised to 195°C and a polycondensation reaction was carried out for 6 hours. The temperature was lowered to below 60°C and the product was poured into anhydrous ethanol to precipitate the product. The product was washed 6 times with distilled water and finally dried under vacuum at 100°C for 48 hours to obtain PAEK crude powder with two phenyl groups in the inner side chain of the repeating unit.
[0046] Table 1. Formulas for each case
[0047]
[0048] Test case
[0049] The performance of the above materials was tested, and the results are shown in Table 2.
[0050] Table 2 Performance of Each Case
[0051]
[0052] The linear thermal expansion coefficients of materials in formulations 1 to 5 as a function of temperature are shown in the graphs below. Figures 1 to 5 As shown, Figures 1 to 5 The horizontal axis represents temperature in degrees Celsius. As shown in Table 1, formulations 2 to 5, containing phenyl side chains, exhibit improved mechanical properties compared to the conventional PEEK in formulation 1, and their linear expansion coefficient at 110°C is below 48 ppm / K. This indicates that the phenyl-side-chain-containing PEEK of this invention demonstrates good dimensional stability at 10-110°C.
[0053] PAEK coarse powders from formulations 4 and 5 were used for gear injection molding. A sample image of the gear produced using formulation 5 is shown below. Figure 6 As shown, the gear pumps of both were heated (60°C) and tested. The results showed that the gears did not seize up and the gear pumps operated normally, indicating that the product of this invention has high dimensional stability.
[0054] The above description is only a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any equivalent substitutions or modifications made by those skilled in the art within the scope of the technology disclosed in the present invention, based on the technical solution and inventive concept of the present invention, should be covered within the scope of protection of the present invention.
Claims
1. A method for preparing a polyaryl ether ketone with a low coefficient of thermal expansion, characterized in that, Includes the following steps: In a protective atmosphere, difluorobenzophenone and hydroquinone compounds undergo a salt formation reaction in the presence of carbonates and reaction solvents, followed by a polycondensation reaction at elevated temperature to obtain polyaryl ether ketone prepolymers. The quinone compounds mentioned above are selected from one or more of resorcinol, hydroquinone, phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol; The molar ratio of the difluorobenzophenone to the hydroquinone compound is 1-1.1:
1.
2. The method for preparing a low-expansion-coefficient polyaryl ether ketone according to claim 1, characterized in that, The quinone compounds are selected from the first combination or the second combination. The first combination is a combination of one or more of resorcinol and hydroquinone with one or more of phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol. The second combination is one or more of phenylhydroquinone, 2,5-diphenylhydroquinone, and 1,4-naphthol. In the first combination, the molar percentage of one or more of the resorcinol and hydroquinone is less than or equal to 50%.
3. The method for preparing a low-expansion-coefficient polyaryl ether ketone according to claim 2, characterized in that, The carbonate is selected from sodium carbonate and / or potassium carbonate, and the powder particle size is less than 200 mesh. The amount of the carbonate used is 1-2 times the total molar amount of the difluorobenzophenone and the hydroquinone compound. The reaction solvent is selected from one or more of N,N-dimethylformamide, N,N-dimethylacetamide, N-methylpyrrolidone, and dimethyl sulfoxide. Toluene, an azeotropic agent, is added to the reaction system. The amount of the reaction solvent is 4-6 times the total molar amount of the difluorobenzophenone and the hydroquinone compounds, and the amount of the azeotropic agent is 10-20% of the mass of the reaction solvent.
4. The method for preparing a low-expansion-coefficient polyaryl ether ketone according to claim 2, characterized in that, The salt formation reaction is carried out at a temperature of 140-160℃ for 1-5 hours.
5. The method for preparing a low-expansion-coefficient polyaryl ether ketone according to claim 2, characterized in that, The polycondensation reaction is carried out at a temperature of 180-205℃ for 3-8 hours.
6. The method for preparing a low-expansion-coefficient polyaryl ether ketone according to claim 2, characterized in that, After the polycondensation reaction is completed, the process also includes adding a poor solvent to the reaction system to precipitate, wash, and dry the product; the poor solvent is an alcohol solvent and / or water.
7. A polyaryl ether ketone with a low coefficient of thermal expansion, characterized in that, Made by any one of claims 1-6, the linear expansion coefficient at 10-110°C is less than 48 ppm / K.