PEEK composite material, preparation method thereof and plastic part

Abstract

The invention provides a PEEK composite material, a preparation method thereof and a plastic part, and belongs to the field of high polymer material manufacturing. The low-melt-viscosity PEEK composite material is prepared from the copolymerized polyether-ether-ketone resin with proper viscosity and melting point, and the array carbon nanotubes are not easy to agglomerate due to the characteristic of low melt viscosity in combination with washing and pretreatment of the copolymerized polyether-ether-ketone resin, so that the mechanical property of the pipe is improved, the service life of the pipe is prolonged, and the welding strength of the pipe is improved. According to the result of the embodiment, the tensile strength of the prepared pipe is 96-100 MPa, the elongation at break is 54-110%, the volume resistance is 104-109 ohm, the pipe is easy to weld and good in toughness, bending of the pipe can be achieved, and the bursting pressure of the welded pipe is equivalent to that of a pure pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of high polymer material manufacturing, in particular to a PEEK composite material, a preparation method thereof and a plastic part. BACKGROUND

[0002] PEEK pipeline is prepared by taking PEEK as the main material. Due to the excellent performance of PEEK resin, PEEK pipe can withstand high pressure and frequent pulse pressure, and has excellent corrosion resistance and is not affected by strong acid, strong alkali and commonly used organic solvents. However, due to the high melting point and high melt viscosity of PEEK resin, the processing equipment and process are harsh. Especially for PEEK thin-walled pipe, in the process of extrusion molding, it is necessary to accurately control the temperature, pressure and extrusion speed and other parameters, otherwise defects of the product are prone to occur, which increases the difficulty and cost of processing. At the same time, the fast crystallization rate of PEEK resin also leads to high difficulty in welding PEEK pipeline, especially the low strength of PEEK thin-walled pipe after welding.

[0003] In addition, in the fields of petrochemical industry, aerospace, etc., especially in the transportation of flammable and explosive liquids such as petroleum, the liquid is easy to produce static electricity when contacting with the plastic pipeline, which causes safety hazards. In order to solve this problem, an antistatic agent is usually added to the PEEK resin. The commonly used antistatic agents mainly include graphite, carbon fiber and array carbon nanotube. The above micron-sized graphite and carbon fiber need a high filling amount (≥10wt%) to have good effect, however, the introduction of a large amount of micron-sized fillers will reduce the toughness of the composite material, which is not conducive to the subsequent bending and other processing of the pipeline. The array carbon nanotube can effectively improve the antistatic performance of the PEEK composite material at a low content due to its high aspect ratio, however, the high melt viscosity of PEEK resin and the easy agglomeration of array carbon nanotube lead to high difficulty in controlling during the extrusion process of thin-walled pipe, and the pipe surface is easy to produce processing lines, which affects the mechanical properties and service life of the pipe. SUMMARY

[0004] The present application provides a PEEK composite material, a preparation method thereof and a plastic part. The pipe prepared by taking the PEEK composite material prepared by the preparation method of the present application as the raw material has excellent mechanical properties, long service life and high welding strength.

[0005] The present application provides a preparation method of a PEEK composite material, which comprises the following steps:

[0006] The washed copolytype polyether ether ketone resin and the pretreated array carbon nanotube are mixed and then subjected to melt extrusion and granulation to obtain the PEEK composite material;

[0007] The copolytype polyether ether ketone resin has a structural formula shown in formula I:

[0008]

[0009] At 400°C and 500N, the melt index of the copolymerized polyetheretherketone resin before washing is 23 to 80 g / 10 min.

[0010] The pretreatment temperature is 380-400°C, the time is 1-4 hours, and the vacuum degree is ≤0.1Pa;

[0011] The washing comprises repeatedly washing with an organic solvent and water in sequence;

[0012] The organic solvent includes acetone and / or ethyl acetate.

[0013] Preferably, the washed copolymerized polyetheretherketone resin contains less than 200 ppm of diphenyl sulfone solvent and less than 200 ppm of inorganic salt.

[0014] Preferably, the mass ratio of the washed copolymerized polyetheretherketone resin to the pretreated array carbon nanotubes is 16 to 99:1.

[0015] Preferably, the aspect ratio of the arrayed carbon nanotubes before pretreatment is 200-1500.

[0016] Preferably, the number of repetitions is 4 times.

[0017] Preferably, the melt extrusion is carried out in a twin-screw extruder;

[0018] The speed of the twin-screw extruder is 200-300 r / min, the feeding temperature is 220-240° C., the temperature of the extrusion section is 320-350° C., and the temperature at the extrusion die is 300-330° C.

[0019] The present invention also provides a PEEK composite material prepared by the preparation method described in the above technical solution.

[0020] The present invention also provides a plastic part, the raw material of which includes the PEEK composite material described in the above technical solution.

[0021] The present invention uses a copolymerized polyetheretherketone resin with suitable viscosity and melting point to prepare a low melt viscosity PEEK composite material. The low melt viscosity, combined with the washing and pretreatment of the copolymerized polyetheretherketone resin, makes it difficult for the array carbon nanotubes to agglomerate, thereby improving the mechanical properties, service life, and welding strength of the pipe. The results of the embodiment show that the tensile strength of the pipe prepared by the present invention is 96-100 MPa, the elongation at break is 54-110%, and the volume resistivity is 10 4 ~10 9 Ω, easy to weld, good toughness, can realize the bending of pipes, and the bursting pressure of the pipes after welding is equivalent to that of pure pipes. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 SEM images of arrayed carbon nanotubes used in the examples and comparative examples;

[0023] Figure 2 This is the DSC test curve of the PEEK composite material of Example 3;

[0024] Figure 3 is the tensile property curve of the PEEK composite material of Example 3;

[0025] Figure 4 This is a photo of the PEEK composite pipe in the embodiment;

[0026] Figure 5 These are pictures of the PEEK composite pipe of Example 3 after welding and blasting. DETAILED DESCRIPTION

[0027] The present invention provides a method for preparing a PEEK composite material, comprising the following steps:

[0028] The washed copolymerized polyetheretherketone resin and the pretreated arrayed carbon nanotubes are mixed, melt-extruded, and granulated to obtain the PEEK composite material;

[0029] The copolymerized polyetheretherketone resin has the structural formula shown in Formula I:

[0030]

[0031] At 400°C and 500N, the melt index of the copolymerized polyetheretherketone resin before washing is 23 to 80 g / 10 min.

[0032] The pretreatment temperature is 380-400°C, the time is 1-4 hours, and the vacuum degree is ≤0.1Pa;

[0033] The washing comprises repeatedly washing with an organic solvent and water in sequence;

[0034] The organic solvent includes acetone and / or ethyl acetate.

[0035] In the present invention, the washing comprises repeatedly washing with acetone and water in sequence, and the number of repetitions is 4. The washing can remove the effects of residual solvent and catalyst on the surface of the thin-walled tube.

[0036] In the present invention, the content of diphenyl sulfone as a solvent in the washed copolymerized polyetheretherketone resin is preferably less than 200 ppm, and the content of inorganic salt is preferably less than 200 ppm.

[0037] In the present invention, at 400°C and 500N, the melt index of the copolymerized polyetheretherketone resin before washing is 23 to 80 g / 10min. In a specific embodiment of the present invention, the melt index of the copolymerized polyetheretherketone resin before washing may be 30 g / 10min, 40 g / 10min, 50 g / 10min, 60 g / 10min or 70 g / 10min; the mass ratio of the washed copolymerized polyetheretherketone resin to the pretreated array carbon nanotubes is preferably 16 to 99:1. In a specific embodiment of the present invention, it may be 20:1, 30:1, 40:1, 50:1, 60:1, 70:1, 80:1 or 90:1.

[0038] In the present invention, the pretreatment temperature is 380-400° C., the time is 1-4 hours, and the vacuum degree is ≤0.1 Pa. The pretreatment eliminates the surface active groups of the carbon nanotubes, thereby preventing the surface active groups of the carbon nanotubes from affecting the pipe surface during the extrusion process.

[0039] In the present invention, the melt extrusion is preferably carried out in a twin-screw extruder; the speed of the twin-screw extruder is preferably 200-300 r / min, the feeding temperature is preferably 220-240°C, the extrusion section temperature is preferably 320-350°C, and the temperature at the extrusion die is preferably 300-330°C.

[0040] The present invention also provides a method for preparing a PEEK composite material.

[0041] The present invention also provides a plastic part, the raw material of which includes the PEEK composite material described in the above technical solution.

[0042] The PEEK composite material, its preparation method, and the plastic part provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0043] Example 1

[0044] (1) Pretreatment of carbon nanotube arrays (GT210): vacuum treatment at 400°C for 4 h, with a vacuum degree of 0.1 Pa.

[0045] (2) Copolymer PEEK resin purification: The 3D printed polyetheretherketone interlayer reinforcement material prepared in Example 1 of CN114805789A was washed with acetone and deionized water in turn for 4 times (acetone and deionized water washing for one time).

[0046] (3) A twin-screw extruder with a side feeder is used to mix the copolymerized PEEK resin of step (2) and the arrayed carbon nanotubes of step (1). The weight ratio of the copolymerized PEEK resin and the arrayed carbon nanotube materials is 98:2. The copolymerized PEEK resin is located at the main feed port, and the arrayed carbon nanotubes are located at the side feed port. The twin-screw extruder speed is 300 r / min, the feeding temperature is 240°C, the extrusion section temperature is 350°C, and the temperature at the extrusion die is 330°C. After pelletizing, an antistatic high-toughness composite material pellet-1 is prepared.

[0047] High-temperature injection molding machines are used to mold tensile and volume resistivity test specimens. The dimensions and test methods for tensile specimens are in accordance with GB / T 1040.2-2022; the dimensions and test methods for volume resistivity specimens are in accordance with GB / T 31838.2-2019.

[0048] The composite material has a tensile strength of 96 MPa, an elongation at break of 54%, and a volume resistivity of 10 9 Ω.

[0049] Using antistatic, high-toughness composite material pellet-1 as raw material, a high-temperature pipe extruder was used to extrude an antistatic pipe with an outer diameter of 40 mm and a wall thickness of 1.5 mm. The extruder speed was 50 r / min, the feed temperature was 240°C, the extrusion section temperature was 350°C, and the extrusion die temperature was 320°C. After vacuum sizing, water cooling, and air cooling, the pipe was cut into the desired length of antistatic PEEK tubing. After welding two antistatic PEEK tubing (welding conditions: 300°C, heating for 10 seconds, vacuum welding, welding rate of 3 m / min, curing rate of 1 m / min), the pipe had a burst pressure of 7.5 MPa, with the burst point occurring in the pipe section.

[0050] Example 2

[0051] The only difference from Example 1 is that in step (3), the weight ratio of the copolymerized PEEK resin and the array carbon nanotube material is 97:3. The composite material has a tensile strength of 98 MPa, an elongation at break of 60%, and a volume resistivity of 10 8 The bursting pressure of the pipe is 7.8 MPa, and the bursting point occurs in the pipe part.

[0052] Example 3

[0053] The only difference from Example 1 is that in step (3), the weight ratio of the copolymerized PEEK resin and the array carbon nanotube material is 96:6. The composite material has a tensile strength of 96 MPa, an elongation at break of 110%, and a volume resistivity of 10 6 The bursting pressure of the pipe is 8MPa, and the bursting point occurs in the pipe part.

[0054] Figure 5 These are pictures of the PEEK composite pipe in Example 3 after welding and blasting.

[0055] Depend on Figure 5 It can be seen that the burst point occurs in the pipe part, and the burst strength of the welded part is higher than that of the pure pipe. The burst pressure of the welded pipe is 8MPa.

[0056] Example 4

[0057] The only difference from Example 1 is that in step (3), the weight ratio of the copolymerized PEEK resin and the array carbon nanotube material is 95:5. The composite material has a tensile strength of 100 MPa, an elongation at break of 80%, and a volume resistivity of 10 4 The bursting pressure of the pipe is 8MPa, and the bursting point occurs in the pipe part.

[0058] Example 5

[0059] The only difference from Example 3 is that in step (5), a high-temperature pipe extruder is used to extrude an antistatic pipe with an outer diameter of 60 mm and a wall thickness of 1.5 mm. The bursting pressure of the pipe is 5.3 MPa, and the bursting point occurs in the pipe portion.

[0060] Example 6

[0061] The only difference from Example 3 is that acetone is replaced by ethyl acetate. The composite material has a tensile strength of 90 MPa, an elongation at break of 22%, and a volume resistivity of 10 10 The bursting pressure of the pipe is 7.1 MPa, and the bursting point occurs in the pipe.

[0062] Comparative Example 1

[0063] The only difference from Example 3 is that the array carbon nanotubes are not treated in step (1). The composite material has a tensile strength of 94 MPa, an elongation at break of 28%, and a volume resistivity of 10 10 Ω. The bursting pressure of the pipe is 6.4MPa.

[0064] Comparative Example 2

[0065] The only difference from Example 3 is that the copolymerized PEEK resin is not purified in step (2). The composite material has a tensile strength of 96 MPa, an elongation at break of 38%, and a volume resistivity of 10 10 Ω. Pipe bursting pressure 6.5MPa.

[0066] Figure 1 These are SEM images of arrayed carbon nanotubes used in the examples and comparative examples.

[0067] from Figure 1 It can be found that the arrayed carbon nanotubes have a certain directional arrangement, which is beneficial to the dispersion of the arrayed carbon nanotubes during the processing.

[0068] Figure 2This is the DSC test curve of the PEEK composite material of Example 3.

[0069] from Figure 2 It can be found that the glass transition temperature of PEEK composite material is 152°C and the melting point is 298°C, which is more than 7°C higher than the glass transition temperature (146°C) of PEEK and its composite material, and the melting point (340°C) is 40°C lower. At the same time, the cold crystallization peak temperature of the material is 200°C, which is higher than the cold crystallization peak of PEEK resin (176°C), indicating a decrease in the crystallization rate of the material. The reduction in melting point and crystallization rate is conducive to the welding of composite materials, ensuring the strength of the composite materials after welding.

[0070] Figure 3 This is the tensile property curve of the PEEK composite material of Example 3.

[0071] from Figure 3 It can be found that the prepared PEEK composite material has a tensile strength of 96 MPa and an elongation at break of up to 110%.

[0072] Figure 4 This is a photo of the PEEK composite pipe in the example. The pipe has an outer diameter of 40 mm and a wall thickness of about 1.5 mm.

[0073] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as within the scope of protection of the present invention.

Claims

1. A method for preparing a PEEK composite material, characterized in that: The following steps are involved: The washed copolymerized polyetheretherketone resin and the pretreated arrayed carbon nanotubes are mixed, melt-extruded, and granulated to obtain the PEEK composite material; The copolymerized polyetheretherketone resin has the structural formula shown in Formula I: At 400°C and 500N, the melt index of the copolymerized polyetheretherketone resin before washing is 23 to 80 g / 10 min. The pretreatment temperature is 380-400°C, the time is 1-4 hours, and the vacuum degree is ≤0.1Pa; The washing comprises repeatedly washing with an organic solvent and water in sequence; The organic solvent includes acetone and / or ethyl acetate.

2. The preparation method according to claim 1, characterized in that The washed copolymerized polyetheretherketone resin has a diphenyl sulfone solvent content of less than 200 ppm and an inorganic salt content of less than 200 ppm.

3. The preparation method according to claim 1, characterized in that The mass ratio of the washed copolymerized polyetheretherketone resin to the pretreated array carbon nanotubes is 16 to 99:

1.

4. The preparation method according to claim 1, characterized in that The aspect ratio of the arrayed carbon nanotubes before the pretreatment is 200-1500.

5. The preparation method according to claim 1 or 3, characterized in that The number of repetitions is 4 times.

6. The preparation method according to claim 1, characterized in that The melt extrusion is carried out in a twin-screw extruder; The speed of the twin-screw extruder is 200-300 r / min, the feeding temperature is 220-240° C., the temperature of the extrusion section is 320-350° C., and the temperature at the extrusion die is 300-330° C.

7. A PEEK composite material prepared by the preparation method according to any one of claims 1 to 6.

8. A plastic part, characterized in that: The raw material of the plastic part includes the PEEK composite material according to claim 7.

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