A method for removing residual diphenyl sulfone in PEEK material

Abstract

The present invention relates to the technical field of PEEK materials, and particularly to a method for removing residual diphenyl sulfone in PEEK materials, comprising the following steps: S1 Pretreatment: Clean the surface of the PEEK material, and after cleaning, freeze-dry it under vacuum for standby; S2 Gradient removal: Place the PEEK material treated in step S1 in a tray, and then place it in a gradient removal device for gradient removal; S3 Heat preservation: Keep the PEEK material treated in step S2 at a certain temperature; S4 Cooling: Cool the PEEK material treated in step S3 to room temperature and take it out. The purpose is to solve the problem pointed out in the background technology that due to the residual diphenyl sulfone in polyether ether ketone, when polyether ether ketone is used as a material in the food industry and at higher temperatures, the residual diphenyl sulfone will gradually volatilize during use, causing some impacts on the environment and health. Through the method provided in this solution, the residual diphenyl sulfone in polyether ether ketone can be completely removed, enabling the PEEK material to meet the requirements for use in the food industry at higher temperatures.

Description

Technical Field

[0001] The present invention relates to the technical field of PEEK materials, and particularly to a method for removing residual diphenyl sulfone in PEEK materials. Background Art

[0002] Polyetheretherketone (PEEK) is a high polymer composed of repeating units containing a ketone bond and two ether bonds in the main chain structure, belonging to special polymer materials. It has high mechanical strength, high temperature resistance, impact resistance, flame retardancy, acid and alkali resistance, hydrolysis resistance, wear resistance, fatigue resistance, radiation resistance and good electrical properties. It is a kind of semi-crystalline polymer material, which can be used as high temperature resistant structural materials and electrical insulating materials, and can be compounded with glass fiber or carbon fiber to prepare reinforcing materials.

[0003] When preparing polyetheretherketone, generally 4,4'-difluorobenzophenone, hydroquinone and potassium carbonate are used as raw materials, and diphenyl sulfone is used as a solvent for synthesis. During the preparation process, the polymer crystallizes out together with inorganic salts, sodium fluoride, potassium fluoride and diphenyl sulfone. Although diphenyl sulfone crystals can be removed by acetone extraction, pressure filtration and acetone washing of the precipitate, there will still be residual diphenyl sulfone in the polyetheretherketone polymer. When polyetheretherketone is used as a material in some food industries and under higher temperature conditions, the residual diphenyl sulfone will gradually volatilize during use, causing some impacts on the environment and health. Therefore, when polyetheretherketone is used as a material in the food industry and under higher temperature conditions, the residual diphenyl sulfone in polyetheretherketone must be removed. However, at present, there is no good method to completely remove the residual diphenyl sulfone when polyetheretherketone is used as a material in the food industry and under higher temperature conditions. Summary of the Invention

[0004] In view of this, the purpose of the present invention is to provide a method for removing residual diphenyl sulfone in PEEK materials, which is used to solve the problem pointed out in the background art that due to the residual diphenyl sulfone in polyetheretherketone, when polyetheretherketone is used as a material in the food industry and under higher temperature conditions, the residual diphenyl sulfone will gradually volatilize during use, causing some impacts on the environment and health. Through the method provided by this solution, the residual diphenyl sulfone in polyetheretherketone can be completely removed, so that the PEEK material can meet the use requirements in the food industry at higher temperatures.

[0005] The present invention solves the above technical problems through the following technical means:

[0006] A method for removing residual diphenyl sulfone in PEEK materials, comprising the following steps:

[0007] S1 Pretreatment: Clean the surface of the PEEK material, and after cleaning, freeze-dry it under vacuum for standby;

[0008] S2 Gradient Removal: Place the PEEK material processed in step S1 in a tray, and then place it in a gradient removal device for gradient removal;

[0009] S3 Heat Preservation: Keep the PEEK material processed in step S2 warm;

[0010] S4 Cooling: Cool the PEEK material processed in step S3 to room temperature and take it out.

[0011] By surface-treating the polyetheretherketone, remove the surface impurities of the polyetheretherketone, and then use a gradient removal device to gradient-remove the residual diphenyl sulfone in the polyetheretherketone. Through heat preservation, the diphenyl sulfone in the polyetheretherketone is completely removed, obtaining a polyetheretherketone material without diphenyl sulfone.

[0012] Furthermore, in the S1 step, during the surface cleaning process of the PEEK material, it is processed using an atmospheric pressure plasma treatment device.

[0013] Through the atmospheric pressure plasma treatment device, the impurities attached to the PEEK material can be fully removed, and the PEEK material can be activated, which is more conducive to the subsequent steps.

[0014] Furthermore, the processing conditions of the plasma treatment device are: steep pulses with an amplitude of 400 - 700v, a pulse width of 30 - 70, and a repetition frequency of 500 - 1000Hz.

[0015] By controlling the processing conditions of the plasma device for the PEEK material, the microscopic appearance of the polyetheretherketone surface can change instantaneously, which is beneficial to the volatilization of the residual diphenyl sulfone in the polyetheretherketone and does not damage the appearance of the polyetheretherketone.

[0016] Furthermore, in the S2 step, the conditions for gradient removal are: gradient heating, and during the gradient heating process, microwave oscillation is carried out synchronously.

[0017] By controlling the gradient heating process and the microwave oscillation process of the gradient removal device, the residual diphenyl sulfone in the polyetheretherketone can be fully volatilized without damaging the inherent properties of the polyetheretherketone material itself, thereby fully removing the diphenyl sulfone from the polyetheretherketone.

[0018] Furthermore, during the gradient heating process, the heating conditions are: rising at a rate of 5 - 10°C per minute until the temperature reaches the preset temperature, and the preset temperature is 230 - 250°C.

[0019] Due to the presence of fiber-reinforced materials in the polyether ether ketone material, the fiber-reinforced material is glass fiber with a content of 25%. Its heat deflection temperature under load is as high as 316°C, the instantaneous use temperature can reach 300°C, and it can be used under the condition of 260°C for a long time. The melting temperature of diphenyl sulfone is 125 - 129°C. By controlling the temperature of gradient heating, the polyether ether ketone material can be fully heated, enabling the residual diphenyl sulfone to escape to the surface of the polyether ether ketone, accelerating the volatilization of diphenyl sulfone. And by limiting the maximum heating temperature of the polyether ether ketone, not only can diphenyl sulfone be volatilized quickly, but also the mechanical properties of the polyether ether ketone will not be damaged, and it also helps to improve the mechanical properties of the polyether ether ketone.

[0020] Further, the conditions of the microwave oscillation are: the frequency is 350 - 1200 MHz, and the power density is 4 - 8 mW / cm 2 .

[0021] By synchronously turning on the microwave oscillation when heating the polyether ether ketone, since the polyether ether ketone basically does not absorb microwave energy, but the microwave directly penetrates the polyether ether ketone, causing the molecules of the polyether ether ketone to oscillate and further changing the microscopic appearance of the polyether ether ketone. Combining with the heating of the polyether ether ketone, the residual diphenyl sulfone in the polyether ether ketone can be volatilized more completely and quickly. And by controlling the frequency and power density of the microwave, the polyether ether ketone basically does not generate a thermal effect due to the microwave, which is beneficial to the overall temperature control, and thus can remove the residual diphenyl sulfone under the temperature conditions conducive to improving the mechanical properties of the polyether ether ketone.

[0022] Further, the gradient removal device includes a box body, a heating element, a microwave element and a box door. The heating element is arranged at the bottom of the box body, the microwave element is arranged on both sides of the inner wall of the box body, and the box door is arranged at the opening of the box body.

[0023] Through the mutual cooperation of the heating element and the microwave element, they can be started synchronously, so as to heat and perform microwave oscillation on the polyether ether ketone material synchronously, and further enable all the diphenyl sulfone in the polyether ether ketone to be removed, and at the same time, accelerate the removal speed of diphenyl sulfone.

[0024] Further, the heating element includes a heating coil, a mounting seat and a heat transfer plate. The mounting seat is fixedly installed on the box body, the heating coil is circumferentially distributed on the mounting seat, and the heat transfer plate is connected to the mounting seat.

[0025] Through the operation of the heating coil, the polyether ether ketone can be heated evenly, and it is more conducive to controlling the heating temperature.

[0026] Further, the microwave element includes a magnetron, a fixed seat and a heat insulation plate. Both sides of the box body have mounting grooves, the fixed seat is installed in the mounting grooves, the fixed seat has a cavity, a blocking layer is arranged in the cavity, the magnetron is installed in the cavity, and the heat insulation plate is installed on the mounting grooves.

[0027] Through the operation of two magnetrons, gradient microwave oscillation can be performed on polyether ether ketone, so that the residual diphenyl sulfone in the polyether ether ketone can be oscillated, and when changing the microscopic appearance of the polyether ether ketone, it plays a positive role. Combined with heating, the molecular gaps on the surface of the polyether ether ketone are increased, so that the deep-seated diphenyl sulfone in the polyether ether ketone volatilizes.

[0028] Further, in the step S3, the heat preservation time is 30 - 60 min.

[0029] By adopting the heat preservation operation and controlling the heat preservation time, on the one hand, the residual diphenyl sulfone in the polyether ether ketone can be completely volatilized, and on the other hand, the polyether ether ketone material is prevented from being immediately cooled, resulting in the inability of part of the diphenyl sulfone volatilized to the inner surface of the polyether ether ketone to volatilize, thus causing incomplete removal of the diphenyl sulfone.

[0030] Advantages of the present invention:

[0031] 1. By performing surface treatment, heating and microwave gradient control on the polyether ether ketone material, gradient removal of residual diphenyl sulfone from the polyether ether ketone is carried out. In combination with the heat preservation process, the residual diphenyl sulfone in the polyether ether ketone can be completely removed. Without affecting the appearance of the polyether ether ketone, the mechanical properties of the polyether ether ketone can be improved, enabling the polyether ether ketone material to meet the use requirements in the food industry at higher temperatures;

[0032] 2. By controlling the treatment conditions of atmospheric pressure plasma during the surface treatment of the polyether ether ketone, the microscopic appearance of the polyether ether ketone surface changes positively, which is beneficial to the exposure of the molecular gaps on its surface. Combined with gradient heating and gradient microwaves, the molecules in the polyether ether ketone are further oscillated, so that all the diphenyl sulfone in the polyether ether ketone volatilizes without damaging the polyether ether ketone;

[0033] 3. The operation of removing the residual diphenyl sulfone in the polyether ether ketone in this solution is simple, convenient and efficient, providing a new idea for the use of this material in the food industry at higher temperatures. Description of the drawings

[0034] Figure 1 It is the diphenyl sulfone detection diagram of the polyether ether ketone before treatment in a method for removing residual diphenyl sulfone from PEEK material of the present invention;

[0035] Figure 2 It is the diphenyl sulfone detection diagram of the polyether ether ketone after treatment in Example 1 in a method for removing residual diphenyl sulfone from PEEK material of the present invention;

[0036] Figure 3 It is the diphenyl sulfone detection diagram of the polyether ether ketone after treatment in Example 2 in a method for removing residual diphenyl sulfone from PEEK material of the present invention;

[0037] Figure 4 It is the detection diagram of diphenyl sulfone in Example 3 after the polyether ether ketone treatment in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0038] Figure 5 It is the scanning electron microscope image when the polyether ether ketone is untreated in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0039] Figure 6 It is the scanning electron microscope image of the polyether ether ketone after treatment in Example 1 in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0040] Figure 7 It is the scanning electron microscope image of the polyether ether ketone after treatment in Example 2 in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0041] Figure 8 It is the scanning electron microscope image of the polyether ether ketone after treatment in Example 3 in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0042] Figure 9 It is the schematic structural diagram of the gradient removal device in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0043] Figure 10 It is the schematic sectional structural diagram of the gradient removal device in a method for removing residual diphenyl sulfone in PEEK material according to the present invention;

[0044] Among them, there are a box body 1, a box door 2, a controller 3, a mounting seat 4, a heating coil 41, a heat transfer plate 42, a fixing seat 5, a magnetron 51, and a heat insulation plate 52. Specific embodiments

[0045] The present invention will be described in detail below in conjunction with the drawings and specific embodiments:

[0046] Example 1, Method 1 for removing residual diphenyl sulfone in PEEK material

[0047] It includes the following steps:

[0048] S1 Pretreatment: Place the PEEK material in an atmospheric pressure plasma treatment device, and perform surface cleaning with steep pulses having an amplitude of 400V, a pulse width of 30, and a repetition frequency of 500Hz for 5 minutes. After cleaning, place it in a vacuum freeze dryer and perform vacuum freeze-drying at -5°C for 2 minutes. Through vacuum freeze-drying, the changed microscopic appearance of the polyether ether ketone is fixed and reserved;

[0049] S2 Gradient Removal: Place the PEEK material processed in step S1 in a tray, and then place it in a gradient removal device for gradient removal. In this embodiment, as Figures 9 - 10 shown, the gradient removal device includes a box body 1, a heating element, a microwave element, and a box door 2. The heating element is arranged at the bottom of the box body 1, the microwave element is arranged on both sides of the inner wall of the box body 1, and the box door 2 is arranged at the opening of the box body 1. Through the mutual cooperation of the heating element and the microwave element, they can be started synchronously, so as to heat and microwave oscillate the polyether ether ketone material synchronously, and then all the diphenyl sulfone in the polyether ether ketone can be removed. At the same time, the removal speed of diphenyl sulfone is accelerated.

[0050] In this embodiment, a controller 3 and a display screen are also arranged outside the box body 1. The controller 3 is electrically connected to the heating element and the microwave element, the display screen is electrically connected to the controller 3, and adjustment buttons are arranged on the controller 3, so that the temperature rising conditions of the heating element and the working conditions of the microwave element can be controlled and displayed on the display screen in real time.

[0051] In this embodiment, the heating element includes a heating coil 41, a mounting seat 4, and a heat transfer plate 42. The mounting seat 4 is fixedly installed at the bottom of the box body 1 by bolts. The heating coil 41 is circumferentially distributed on the mounting seat 4. The heating coil 41 is a resistance wire. The heat transfer plate 42 is fixedly connected to the mounting seat 4 by bolts. The heat transfer plate 42 is preferably a copper plate. Through the work of the resistance wire, the polyether ether ketone can be heated evenly, and it is more conducive to controlling the heating temperature.

[0052] In this embodiment, the microwave element includes a magnetron 51, a fixing seat 5, and a heat insulation plate 52. There are installation grooves on both sides of the box body 1. The fixing seat 5 is fixedly installed in the installation groove by bolts. The fixing seat 5 has a cavity, and a blocking layer is arranged in the cavity. The blocking layer is an aluminum alloy coating, and the aluminum alloy coating is evenly coated on the inner wall of the cavity by electroplating. When the magnetron 51 works, the microwave can propagate from the outlet of the cavity, reducing the loss. The magnetron 51 is fixedly installed in the cavity, and the heat insulation plate 52 is fixedly installed on the installation groove by bolts. The heat insulation plate 52 is preferably a vacuum heat insulation plate, which not only has good heat insulation performance but also does not block the penetration of the microwave. Through the work of the two magnetrons 51, the polyether ether ketone can be subjected to gradient microwave oscillation, so that the residual diphenyl sulfone in the polyether ether ketone can be oscillated, and it plays a positive role when changing the microscopic appearance of the polyether ether ketone. Cooperating with the temperature rise, the molecular gap on the surface of the polyether ether ketone is increased, so that the diphenyl sulfone deep in the polyether ether ketone volatilizes.

[0053] In this embodiment, the controller 3 controls the resistance wire to rise in temperature in a gradient heating manner. At a speed of 5 °C / min, the temperature inside the box body 1 is raised to 230 °C. During this process, the controller 3 simultaneously controls the magnetron 51 with a frequency of 350 MHz and a power density of 4 mW / cm 2Work to heat up and microwave oscillate the polyetheretherketone.

[0054] S3 Heat preservation: Keep the PEEK material processed in step S2 in the box at 230 °C for 60 min.

[0055] S4 Cooling: Cool the PEEK material processed in step S3 to room temperature, take it out and test its diphenyl sulfone content.

[0056] Example 2, Method 2 for removing residual diphenyl sulfone from PEEK material

[0057] In this example, the gradient removal device is the same as that in Example 1.

[0058] It includes the following steps:

[0059] S1 Pretreatment: Place the PEEK material in an atmospheric pressure plasma treatment device, perform surface cleaning with steep pulses with an amplitude of 550 v, a pulse width of 50, and a repetition frequency of 800 Hz for 3 min. After cleaning, place it in a vacuum freeze dryer at -5 °C for vacuum freeze-drying for 2 min. Through vacuum freeze-drying, fix the changed microscopic appearance of the polyetheretherketone for standby.

[0060] S2 Gradient removal: Place the PEEK material processed in step S1 in a tray and then in the gradient removal device for gradient removal. In this example, the controller controls the resistance wire to heat up in a gradient heating manner, rising to 240 °C in the box at a speed of 8 °C / min. During this process, the controller simultaneously controls the magnetron to work at a frequency of 750 MHz and a power density of 6 mW / cm 2 Work to heat up and microwave oscillate the polyetheretherketone.

[0061] S3 Heat preservation: Keep the PEEK material processed in step S2 in the box at 230 °C for 45 min.

[0062] S4 Cooling: Cool the PEEK material processed in step S3 to room temperature, take it out and test its diphenyl sulfone content.

[0063] Example 3, Method 3 for removing residual diphenyl sulfone from PEEK material

[0064] In this example, the gradient removal device is the same as that in Example 1.

[0065] It includes the following steps:

[0066] S1 Pretreatment: Place the PEEK material in an atmospheric pressure plasma treatment device and perform surface cleaning with steep pulses having an amplitude of 700V, a pulse width of 70, and a repetition frequency of 1000Hz for 1 minute. After cleaning, place it in a vacuum freeze dryer and perform vacuum freeze drying at -5°C for 2 minutes. Through vacuum freeze drying, the changed microscopic appearance of the polyether ether ketone is fixed for standby;

[0067] S2 Gradient removal: Place the PEEK material processed in step S1 in a tray and then in a gradient removal device for gradient removal. In this embodiment, the controller controls the resistance wire to heat up in a gradient heating manner, rising to 250°C in the box at a speed of 10°C / min. During this process, the controller simultaneously controls the magnetron to work at a frequency of 1200MHz and a power density of 8mW / cm 2 to heat up the polyether ether ketone and perform microwave oscillation;

[0068] S3 Heat preservation: Keep the PEEK material processed in step S2 in the box at 250°C for 30 minutes;

[0069] S4 Cooling: Cool the PEEK material processed in step S3 to room temperature, take it out, and test its diphenyl sulfone content.

[0070] Before the operation of removing diphenyl sulfone from the polyether ether ketone materials in Examples 1 - 3, the diphenyl sulfone content was tested, and the test results are as Figure 1 shown. After the operation of removing diphenyl sulfone from the polyether ether ketone materials in Examples 1 - 3, the diphenyl sulfone content was tested, and the results are as Figures 2 - 4 shown. It can be seen from Figures 2 - 4 that through the method of this solution, the residue of diphenyl sulfone in the polyether ether ketone can be completely removed, enabling the polyether ether ketone material to meet the requirements for use in the food industry at higher temperatures.

[0071] Before the operation of removing diphenyl sulfone from the polyether ether ketone materials in Examples 1 - 3, electron microscopy scanning was performed, as Figure 5 shown. After the operation of removing diphenyl sulfone from the polyether ether ketone materials in Examples 1 - 3, electron microscopy scanning was performed, as Figures 6 - 8 shown. Thus Figures 6 - 8 shown. Through the method of this solution, when removing the residual diphenyl sulfone in the polyether ether ketone, the performance of the material will not be damaged. Moreover, the tensile strength, flexural strength, and thermal weight loss of the materials in Examples 1 - 3 processed by this solution before and after were tested, and the test results are shown in the following table:

[0072]

[0073] It can be clearly concluded from the data in the table that in the process of treating the polyetheretherketone material according to this solution, the tensile strength can be increased by up to 6.2%, and the flexural strength can be increased by up to 15.6%. This shows that this solution can not only remove the residual diphenyl sulfone in the polyetheretherketone, but also improve its mechanical properties. From the thermogravimetric data, it can be clearly concluded that diphenyl sulfone volatilizes in the polyetheretherketone material.

[0074] The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention. The technologies, shapes, and structures not described in detail in the present invention are all well-known technologies.

Claims

1. A method for removing residual diphenyl sulfone in PEEK material, characterized in that, It includes the following steps: S1 Pretreatment: Clean the surface of the PEEK material, and after cleaning, freeze-dry it in vacuum for standby; S2 Gradient removal: Place the PEEK material processed in step S1 in a tray, and then place it in a gradient removal device for gradient removal; S3 Heat preservation: Keep the PEEK material processed in step S2 under heat preservation; S4 Cooling: Cool the PEEK material processed in step S3 to room temperature and take it out; In step S1, during the surface cleaning process of the PEEK material, it is processed by an atmospheric pressure plasma processing device; the processing conditions of the plasma processing device are: steep pulses with an amplitude of 400 - 700V, a pulse width of 30 - 70, and a repetition frequency of 500 - 1000Hz; In step S2, the conditions for gradient removal are: gradient heating, and during the gradient heating process, microwave oscillation is carried out synchronously; the conditions for the microwave oscillation are: a frequency of 350 - 1200MHz and a power density of 4 - 8mW / cm²; During the gradient heating process, the heating condition is: rising at a rate of 5 - 10°C per minute until the temperature reaches the preset temperature, and the preset temperature is 230 - 250°C.

2. The method for removing residual diphenyl sulfone in PEEK material according to claim 1, characterized in that, The gradient removal device includes a box body, a heating element, a microwave element, and a box door. The heating element is arranged at the bottom of the box body, the microwave element is arranged on both sides of the inner wall of the box body, and the box door is arranged at the opening of the box body.

3. The method for removing residual diphenyl sulfone in PEEK material according to claim 2, characterized in that, The heating element includes a heating coil, a mounting seat, and a heat transfer plate. The mounting seat is fixedly installed on the box body, the heating coil is circumferentially distributed on the mounting seat, and the heat transfer plate is connected to the mounting seat.

4. A method for removing residual diphenyl sulfone in PEEK material according to claim 2, characterized in that, The microwave element includes a magnetron, a fixing seat, and a heat insulation plate. There are installation grooves on both sides of the box body. The fixing seat is installed in the installation groove. The fixing seat has a cavity, a blocking layer is arranged in the cavity, the magnetron is installed in the cavity, and the heat insulation plate is installed on the installation groove.

5. A method for removing residual diphenyl sulfone in PEEK material according to claim 1, characterized in that, In step S3, the heat preservation time is 30 - 60min.

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