A PEEK double-layer co-extruded composite film and its preparation method

Abstract

The present invention relates to the technical field of thin film preparation, and specifically relates to a PEEK double-layer co-extruded composite film and a preparation method thereof. The material of the first layer is a PEEK modified material, including a nano-dispersant with a mass percentage of 0.5% - 1.5% and PEEK with a mass percentage of at least 90%; the material of the second layer is a heat-resistant engineering plastic modified material, including a nano-dispersant with a mass percentage of 0.5% - 1.5% and a heat-resistant engineering plastic with a mass percentage of at least 90%; wherein the heat-resistant engineering plastic is selected from one or more of polyarylate, polysulfone, polyetherimide, liquid crystal polyester, polyphenylene sulfide, polyethersulfone, polyimide, aromatic polyamide - aramid, and polytetrafluoroethylene; a co-extruded film is prepared by casting co-extrusion; the PEEK double-layer co-extruded film prepared by the process of the present invention has good interfacial adhesion, and the thickness and shrinkage rate of each layer are well controlled.

Description

Technical Field

[0001] The present invention relates to the technical field of thin film preparation, and particularly relates to a PEEK double-layer co-extruded composite film and a preparation method thereof. Background Art

[0002] In the aerospace field, the surface film based on polyetheretherketone (PEEK) is one of the key materials for composite components, especially during high-temperature processing. The multi-layer co-extrusion technology shows great application potential in this field due to its excellent mechanical and barrier properties. This multi-layer co-extrusion technology involves using multiple extruders to extrude different materials, combining them through a multi-channel die, and then manufacturing a composite material with a multi-layer structure through cooling, shaping, and winding. As an integrated forming technology, this method eliminates subsequent processing steps such as traditional lamination and coating, which helps to reduce costs. The multi-layer co-extruded film combines the excellent properties of multiple polymers and has been widely used in industrial production. However, traditional multi-layer co-extruded films have limitations in terms of thermal stability, operating temperature range, and dimensional stability, which to a certain extent restricts their application in the aerospace field.

[0003] Since PEEK is a special engineering plastic with a relatively high melting point and there are fewer resin types that match it, relatively speaking, there are more single-layer extruded PEEK films, but fewer PEEK multi-layer co-extruded types. Moreover, the shrinkage rates of various materials are different from that of PEEK, so it is difficult to control the interlayer thickness and ratio, and the interlayer bonding force is weak. Summary of the Invention

[0004] In order to solve the technical problems existing in the prior art, a PEEK double-layer co-extruded composite film and a preparation method thereof are provided. The PEEK double-layer co-extruded film prepared by the process of the present invention has good interlayer bonding force, and the thickness and shrinkage rate of each layer are well controlled.

[0005] To achieve the above object, the present invention is realized through the following technical solutions:

[0006] A PEEK double-layer co-extruded composite film, wherein the material of the first layer is a PEEK modified material, and the material of the second layer is a heat-resistant engineering plastic modified material;

[0007] The PEEK modified material includes a nano-dispersant with a mass percentage of 0.5%-1.5% and at least 90% of PEEK by mass;

[0008] The heat-resistant engineering plastic modified material includes a nano-dispersant with a mass percentage of 0.5%-1.5% and a heat-resistant engineering plastic with a mass percentage of at least 90%. The heat-resistant engineering plastic is selected from one or more of polyarylate (PAR), polysulfone (PSF), polyetherimide (PEI), liquid crystal polyester (PLC), polyphenylene sulfide (PPS), polyethersulfone (PES), polyimide (PI), aromatic polyamide - aramid (APA), and polytetrafluoroethylene (PTFE).

[0009] Further, the nano-dispersant is selected from one or more of nano-silica, nano-alumina, nano-titanium dioxide, nano-zinc oxide, nano-magnesium oxide, and nano-aluminum-doped zinc oxide; the primary particle size range of the nano-dispersant is between 5-100nm.

[0010] Further, the melt index of the PEEK at 400°C and a load of 2.16KG ranges from 8-25g / 10min;

[0011] The melt index of the heat-resistant engineering plastic at 380°C and a load of 2.16KG ranges from 5-17g / 10min.

[0012] Further, the total thickness range of the PEEK double-layer co-extruded composite film is 0.4-0.5mm, and the thickness of the first layer accounts for 50% of the total thickness of the PEEK double-layer co-extruded composite film.

[0013] A method for preparing a PEEK double-layer co-extruded composite film includes the following steps:

[0014] S1. Mix PEEK and the nano-dispersant evenly according to the ratio to obtain mixture A for later use;

[0015] Mix the heat-resistant engineering plastic and the nano-dispersant evenly according to the ratio to obtain mixture B for later use;

[0016] S2. Place mixture A and mixture B in two extruders respectively and simultaneously carry out melt blending and extrusion. The melts extruded from mixture A and mixture B converge into a double-layer co-extruded composite head die, and are co-extruded from it to obtain a co-extruded composite intermediate film, which is cooled by being pulled through multiple guide rollers, and finally obtained a PEEK double-layer co-extruded composite film after trimming and winding;

[0017] There is a temperature control device between the double-layer co-extruded composite head die and the first guide roller;

[0018] The temperature of the double-layer co-extrusion composite die head is 300 - 340 °C; the temperature of the temperature control device is 220 - 250 °C; the temperatures of the multiple guide rollers are lower than 200 °C, and in the processing direction, the temperatures of the multiple guide rollers decrease successively, and the temperature difference between each two guide rollers is between 40 - 100 °C.

[0019] Further, the temperature control device is an infrared lamp tube, which is arranged on both sides of the co-extrusion composite intermediate film, and the length of the infrared lamp tube covers the width of the co-extrusion composite intermediate film; the voltage of the infrared lamp tube is 9V, the power is 1000 - 2000W, and the infrared wavelength is 800 - 1400nm; the distance between the infrared lamp tubes on both sides of the co-extrusion composite intermediate film is 50cm, the distance between the infrared lamp tube and the double-layer co-extrusion composite die head is 200cm, and the distance from the first guide roller is 600cm.

[0020] Further, the number of the guide rollers is at least 2; through the traction of a winding machine, the traction speed is set to 25 - 35m / min and the traction tension is 5 - 8N / m.

[0021] Further, a first extruder is used to melt and co-extrude the mixture A, and in the processing direction, the barrel temperature of the first extruder is set as follows: the temperature of heating zone 1 is 250 - 300 °C, and the temperatures of heating zones 2 to 9 are 320 - 380 °C;

[0022] A second extruder is used to melt and co-extrude the mixture B, and in the processing direction, the barrel temperature of the second extruder is set as follows: the temperature of heating zone 1 is 250 - 310 °C, and the temperatures of heating zones 2 to 9 are 320 - 410 °C, and the temperature is set according to the selected heat-resistant engineering plastic at the same time;

[0023] The first extruder and the second extruder are set with the same screw rotation speed and feeding frequency, the screw rotation speed is 15 - 20rpm, and the feeding frequency is 7 - 9Hz;

[0024] The temperature of the double-layer co-extrusion composite die head is 300 - 320 °C.

[0025] Beneficial technical effects:

[0026] In the present invention, PEEK is combined with other heat-resistant engineering plastics, and a multi-layer co-extrusion casting film process is adopted to obtain a double-layer co-extrusion composite film. The composite film of the present invention has good high-temperature resistance and mechanical properties, and is very suitable for use in the aerospace field;

[0027] The present invention utilizes the different properties of two substances. On the one hand, it can reduce the use cost. On the other hand, due to their different characteristics, they can be used in different fields. For example, the composite of PEEK and PI can ensure its mechanical properties. PI is more excellent in aspects such as high temperature resistance, low temperature resistance, water vapor resistance, mechanical properties, and insulation performance, while PEEK has advantages in some specific application fields such as water non-absorbency and toughness; the composite of PEEK and PTFE has a high surface strength on the PEEK side and good lubrication performance and corrosion resistance on the PTFE side, and can be applied to special fields by utilizing the different characteristics of both sides.

[0028] In the present invention, a small amount of nano-dispersant with a specific particle size is added to each layer of material, which can ensure good flow performance of the material during the extrusion process, and at the same time improve the crystallinity of the material during the subsequent multi-stage slow cooling process, thereby enhancing the material strength; the subsequent multi-stage slow cooling step can ensure better shrinkage rate and interlayer bonding force of the material. Brief Description of the Drawings

[0029] Figure 1 It is a schematic diagram of the device involved in the preparation process of the PEEK double-layer co-extrusion composite film of the present invention;

[0030] 1 - First extruder, 2 - Second extruder, 3 - Double-layer co-extrusion composite head die, 4 - Temperature control device, 51 - First guide roller, 52 - Second guide roller, 6 - Rewinder. Detailed Embodiments

[0031] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the embodiments and drawings of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and in no way limits the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0032] Unless otherwise specifically stated, the numerical values set forth in these embodiments do not limit the scope of the present invention. Technologies and methods known to those of ordinary skill in the relevant art may not be discussed in detail, but where appropriate, such technologies and methods should be regarded as part of the specification. In all examples shown and discussed herein, any specific value should be construed as merely exemplary and not as a limitation. Therefore, other examples of the exemplary embodiments may have different values.

[0033] In addition, it should be noted that the use of terms such as "first" and "second" to describe the extruder is only for the convenience of differentiating each device. Without additional statements, these terms have no special meaning, so they should not be construed as limiting the scope of protection of the present invention.

[0034] For the experimental methods without specific conditions indicated in the following examples, they are usually determined according to national standards; if there is no corresponding national standard, they are carried out according to general standard requirements or general methods.

[0035] The PEEK pure resin used hereinafter is provided by Jiangsu Junhua Special Polymer Materials Co., Ltd.;

[0036] The PI resin is provided by Ningbo Dinghang Special Plastics Co., Ltd., with the model TPI AUT210;

[0037] The PTFE resin is provided by Dongguan Chuangnuo Plastic Co., Ltd., with the model TFM 1700;

[0038] The LCP resin is provided by Dongguan Tianzhihong Plastic Co., Ltd., with the model MT1300;

[0039] The nano-dispersant is provided by Jiangsu Tianxing New Materials Co., Ltd.;

[0040] The polyetherimide PEI is provided by Shanghai Jiyi Plastic Co., Ltd., with the model ULTEM 1000EF.

[0041] Example 1

[0042] A PEEK double-layer co-extruded composite film, the material of the first layer is a PEEK modified material, and the material of the second layer is a PI modified material;

[0043] The PEEK modified material is composed of 1% by mass of nano-titanium dioxide (primary particle size of 20 nm) and 99% by mass of PEEK; the melt index of PEEK at 400 °C and a load of 2.16 KG is 12 g / 10 min;

[0044] The PI modified material is composed of 1% by mass of nano-titanium dioxide (primary particle size of 20 nm) and 99% by mass of PI; the melt index of PI at 400 °C and a load of 2.16 KG is 18 g / 10 min;

[0045] The total thickness of the PEEK double-layer co-extruded composite film is 0.4 mm, of which the thickness of the first layer is 0.2 mm and the thickness of the second layer is 0.2 mm.

[0046] The preparation method of the above-mentioned PEEK double-layer co-extruded composite film includes the following steps:

[0047] S1. Mix PEEK and nano-titanium dioxide in a high-speed mixer (SRL-Z300L) according to the ratio. Set the temperature of the mixed material to 70 °C, use 380V alternating current as the power supply, the compressed air pressure is 0.39 - 0.5 MPa, and mix the materials evenly for 4 hours to ensure its dispersion. After mixing evenly, obtain mixed material A for later use.

[0048] Mix PI and nano-titanium dioxide in a high-speed mixer (SRL-Z300L) according to the ratio. Set the temperature of the mixed material to 70 °C, use 380V alternating current as the power supply, the compressed air pressure is 0.39 - 0.5 MPa, and mix the materials evenly for 4 hours to ensure its dispersion. After mixing evenly, obtain mixed material B for later use.

[0049] S2. Use the device as shown in Figure 1 to prepare the co-extruded film. Put the two mixed materials into two hopper bags respectively, and use the vacuum feeding device (RA-DAKS-220) to feed mixed material A and mixed material B into the first extruder 1 and the second extruder 2 respectively. The barrel temperature of the first extruder 1 is set as follows: the temperature of heating zone 1 is 280 °C, and the temperature of heating zones 2 to 9 is 375 °C. The screw speed of the first extruder 1 is 140 rpm and the feeding frequency is 8 Hz; the barrel temperature of the second extruder 2 is set as follows: the temperature of heating zone 1 is 300 °C, and the temperature of heating zones 2 to 9 is 410 °C. The screw speed of the second extruder 2 is 140 rpm and the feeding frequency is 8 Hz.

[0050] The mixed material A and the mixed material B are simultaneously melt-blended and extruded in the first extruder 1 and the second extruder 2 respectively. The melt extruded from the mixed material A and the mixed material B converges into the double-layer co-extrusion composite die head 3, and is co-extruded from it to obtain the co-extruded composite intermediate film. After being drawn, it passes through the temperature control device 4 and multiple guide rollers 5 in sequence for a gradual cooling process ( Figure 1 only two guide rollers are shown in the figure, but in actual production, there are usually more than 4, and the position and thickness of the guide rollers can be set according to the conventional method. The key in the present invention is the control of temperature), and is drawn by the winding machine 6. Set the drawing speed to 30 m / min and the drawing tension to 8 N / m. Finally, through trimming and winding, obtain the PEEK double-layer co-extruded composite film.

[0051] The temperature of the double-layer co-extrusion composite die head 3 is 320 °C.

[0052] The temperature control device 4 is an infrared lamp tube, and the temperature of the lamp tube is adjusted to 240 °C. The temperature control device 4 is arranged on both sides of the co-extruded composite intermediate film, and the length of the infrared lamp tube covers the width of the co-extruded composite intermediate film; the voltage of the infrared lamp tube is 9V, the power is 1600W, and the infrared wavelength is 800-1400nm; the distance between the infrared lamp tubes on both sides of the co-extruded composite intermediate film is 50cm, the distance between the infrared lamp tube and the double-layer co-extrusion composite head die is 200cm, and the distance from the first guide roller is 600cm;

[0053] In the processing direction, the temperature of the first guide roller 51 is 160 °C, and the temperature of the second guide roller 52 is 80 °C, and then it can be directly wound. Multiple normal temperature guide rollers with different heights, thicknesses or diameters can be set subsequently. The setting of the temperature and number of subsequent guide rollers has little influence on the co-extruded film. Compared with the prior art, the main difference affecting the performance of the co-extruded film is that the co-extruded composite intermediate film flowing out of the double-layer co-extrusion composite head die at a high temperature is cooled in stages through infrared lamp tube temperature control and the cooling of the guide rollers, rather than being suddenly cooled, so that the shrinkage rate of the film can be better controlled, and the interlayer thickness and mechanical properties can be guaranteed.

[0054] Example 2

[0055] A PEEK double-layer co-extruded composite film, the material of the first layer is PEEK modified material, and the material of the second layer is PTFE modified material;

[0056] The PEEK modified material is composed of 1% by mass of nano-silica (primary particle size of 50nm) and 99% by mass of PEEK; the melt index of PEEK at 400 °C and 2.16KG load is 12g / 10min;

[0057] The PTFE modified material is composed of 1% by mass of nano-silica (primary particle size of 50nm) and 99% by mass of PTFE; the melt index of PTFE at 360 °C and 2.16KG load is 8g / 10min;

[0058] The total thickness of the PEEK double-layer co-extruded composite film is 0.4mm, of which the thickness of the first layer is 0.2mm and the thickness of the second layer is 0.2mm.

[0059] The preparation method of the above PEEK double-layer co-extruded composite film includes the following steps:

[0060] S1. Mix PEEK and nano-silica in a high-speed mixer (SRL-Z300L) according to the ratio. Set the temperature of the mixed material to 70°C, use 380V alternating current as the power supply, the compressed air pressure is 0.39 - 0.5MPa, and mix the material evenly for 4 hours to ensure its dispersibility. After uniform mixing, obtain mixed material A for later use;

[0061] Mix PTFE and nano-silica in a high-speed mixer (SRL-Z300L) according to the ratio. Set the temperature of the mixed material to 70°C, use 380V alternating current as the power supply, the compressed air pressure is 0.39 - 0.5MPa, and mix the material evenly for 4 hours to ensure its dispersibility. After uniform mixing, obtain mixed material B for later use;

[0062] S2. Use the device as shown in Figure 1 to prepare the co-extruded film. Put the two mixed materials into two hopper bags respectively, and use a vacuum feeding device (RA-DAKS-220) to feed mixed material A and mixed material B into the first extruder 1 and the second extruder 2 respectively. The barrel temperature of the first extruder 1 is set as follows: the temperature of heating zone 1 is 280°C, and the temperature of heating zones 2 to 9 is 375°C. The screw speed of the first extruder 1 is 140 rpm and the feeding frequency is 8 Hz; the barrel temperature of the second extruder 2 is set as follows: the temperature of heating zone 1 is 260°C, and the temperature of heating zones 2 to 9 is 355°C. The screw speed of the second extruder 2 is 140 rpm and the feeding frequency is 8 Hz;

[0063] The mixed material A and the mixed material B are simultaneously melted and co-mixed and extruded in the first extruder 1 and the second extruder 2 respectively. The melt extruded from the mixed material A and the mixed material B converges into the double-layer co-extrusion composite die head mold 3 and is co-extruded from it to obtain the co-extruded composite intermediate film. After traction, it gradually cools through the temperature control device 4 and multiple guide rollers 5. It is tractioned by the winding machine 6, and the traction speed is set to 30 m / min and the traction tension is 8 N / m. Finally, after trimming and winding, the PEEK double-layer co-extruded composite film is obtained;

[0064] The temperature of the double-layer co-extrusion composite die head mold 3 is 320°C;

[0065] The temperature control device 4 is an infrared lamp tube, and the tube temperature is adjusted to 230°C. The temperature control device 4 is arranged on both sides of the co-extruded composite intermediate film, and the length of the infrared lamp tube covers the width of the co-extruded composite intermediate film; the voltage of the infrared lamp tube is 9V, the power is 1500W, and the infrared wavelength is 800 - 1400 nm; the distance between the infrared lamp tubes on both sides of the co-extruded composite intermediate film is 50 cm, the distance between the infrared lamp tube and the double-layer co-extrusion composite die head mold is 200 cm, and the distance from the first guide roller is 600 cm;

[0066] According to the processing direction, the temperature of the first guide roller 51 is 140° C., and the temperature of the second guide roller 52 is 50° C., and the film can be directly wound up later.

[0067] Example 3

[0068] A PEEK double-layer co-extruded composite film, wherein the material of the first layer is a PEEK modified material, and the material of the second layer is a PEI modified material;

[0069] The PEEK modified material is composed of 1% by mass of nano zinc oxide (primary particle size is 20 nm) and 99% by mass of PEEK; the melt index of PEEK at 400° C. and 2.16 kg load is 12 g / 10 min;

[0070] The PEI modified material is composed of 1% by mass of nano zinc oxide (primary particle size is 20 nm) and 99% by mass of PAR; the melt index of PEI at 360° C. and 2.16 kg load is 8 g / 10 min;

[0071] The total thickness of the PEEK double-layer co-extruded composite film is 0.4 mm, of which the thickness of the first layer is 0.2 mm and the thickness of the second layer is 0.2 mm.

[0072] The preparation method of the above-mentioned PEEK double-layer co-extruded composite film comprises the following steps:

[0073] S1. PEEK and nano zinc oxide are mixed at high speed in a high-speed mixer (SRL-Z300L) according to the proportion. The temperature of the mixture is set to 70°C, the power supply is 380V AC, the compressed air pressure is 0.39-0.5MPa, and the mixture is evenly mixed for 4 hours to ensure its dispersibility. Mixing is uniform to obtain a mixture A for standby use;

[0074] PEI and nano zinc oxide were mixed at high speed in a high-speed mixer (SRL-Z300L) according to the proportion, the temperature of the mixture was set to 70°C, the power supply was 380V AC, the compressed air pressure was 0.39-0.5MPa, and the mixture was evenly mixed for 4 hours to ensure its dispersibility. Mixture B was obtained for standby use;

[0075] S2, adopt Figure 1The device shown is used to prepare a coextruded film. Two kinds of mixed materials are respectively put into two hopper bags, and the mixed material A and the mixed material B are fed into the first extruder 1 and the second extruder 2 respectively through a vacuum feeding device (RA-DAKS-220). The barrel temperature of the first extruder 1 is set as follows: the temperature of the first heating zone is 280 °C, and the temperatures of the second to ninth heating zones are 375 °C. The screw speed of the first extruder 1 is 140 rpm and the feeding frequency is 8 Hz. The barrel temperature of the second extruder 2 is set as follows: the temperature of the first heating zone is 270 °C, and the temperatures of the second to ninth heating zones are 320 °C. The screw speed of the second extruder 2 is 140 rpm and the feeding frequency is 8 Hz.

[0076] The mixed material A and the mixed material B are simultaneously melt-blended and extruded in the first extruder 1 and the second extruder 2 respectively. The melts extruded from the mixed material A and the mixed material B converge into a double-layer coextrusion composite die head mold 3, and a coextruded composite intermediate film is coextruded from it. It is gradually cooled through a temperature control device 4 and multiple guide rollers 5 in sequence by traction, and is tractioned by a winder 6. The traction rate is set to 30 m / min and the traction tension is 8 N / m. Finally, a PEEK double-layer coextruded composite film is obtained through edge trimming and winding.

[0077] The temperature of the double-layer coextrusion composite die head mold 3 is 320 °C.

[0078] The temperature control device 4 is an infrared lamp tube, and the tube temperature is adjusted to 220 °C. The temperature control device 4 is arranged on both sides of the coextruded composite intermediate film, and the length of the infrared lamp tube covers the width of the coextruded composite intermediate film. The voltage of the infrared lamp tube is 9 V, the power is 1300 W, and the infrared wavelength is 800 - 1400 nm. The distance between the infrared lamp tubes on both sides of the coextruded composite intermediate film is 50 cm, the distance between the infrared lamp tube and the double-layer coextrusion composite die head mold is 200 cm, and the distance from the first guide roller is 600 cm.

[0079] In the processing direction, the temperature of the first guide roller 51 is 180 °C, and the temperature of the second guide roller 52 is 80 °C, and then it can be directly wound.

[0080] Comparative Example 1

[0081] The preparation of the PEEK double-layer coextruded composite film in this case is the same as that in Example 1, except that the material of the second layer is the same as that of the first layer, and at the same time, the temperature setting of the second extruder is the same as that of the first extruder.

[0082] Comparative Example 2

[0083] The preparation of the PEEK double-layer coextruded composite film in this case is the same as that in Example 1, except that neither the material of the first layer nor the material of the second layer contains a nano-dispersant.

[0084] Comparative Example 3

[0085] The preparation of the PEEK double-layer co-extruded composite film in this example was the same as that in Example 1, except that the temperature control device between the double-layer co-extrusion composite head die and the first guide roll was removed, and the temperatures of the first guide roll and the second guide roll were both at room temperature.

[0086] Comparative Example 4

[0087] The preparation of the PEEK double-layer co-extruded composite film in this example was the same as that in Example 1, except that the temperature control device between the double-layer co-extrusion composite head die and the first guide roll was removed, the temperature of the first guide roll was 160 °C, and the temperature of the second guide roll was 80 °C.

[0088] The film properties of the above examples and comparative examples are shown in Table 1.

[0089] Table 1 Film properties of examples and comparative examples

[0090]

[0091]

[0092] (Note: The test standards for tensile strength and elongation at break are ASTM D882; the test standard for peel strength is ASTM D1876; the ultraviolet light transmittance refers to the average transmittance in the wavelength range of 280 - 380 nm, and the visible light transmittance refers to the average transmittance in the wavelength range of 380 - 1100 nm, which is tested by an ultraviolet-visible spectrophotometer; the test standard for shrinkage rate is ASTM D2732)

[0093] As can be seen from Table 1, the nanoparticles act as a nucleating agent during the film cooling process, while increasing the crystallinity, achieving slow cooling by combining stepwise temperature reduction, and having a lower film shrinkage rate while increasing the strength.

[0094] As described above, the above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A method for preparing a PEEK double-layer co-extruded composite film, characterized in that: The steps include: S1, PEEK and nano-dispersant are mixed uniformly according to a ratio to obtain a mixture A, which is set aside; The heat-resistant engineering plastic and the nano-dispersant are mixed uniformly according to a proportion to obtain a mixed material B for standby use; S2, placing the mixed material A and the mixed material B in two extruders respectively for melt co-extrusion, the melts of the mixed material A and the mixed material B respectively extruded are merged into a double-layer co-extrusion composite die head die, and co-extruded therefrom to obtain a co-extruded composite intermediate film, which is then drawn through a plurality of guide rollers for cooling, and finally trimmed and rolled to obtain a PEEK double-layer co-extruded composite film; The material of the first layer of the PEEK double-layer co-extruded composite film is a PEEK modified material, and the material of the second layer is a heat-resistant engineering plastic modified material; The PEEK modified material includes 1% by mass of a nano-dispersant and 99% by mass of PEEK; The heat-resistant engineering plastic modified material comprises 1% by mass of a nano-dispersant and 99% by mass of a heat-resistant engineering plastic, wherein the heat-resistant engineering plastic is selected from one or more of polyarylate, polysulfone, polyetherimide, liquid crystal polyester, polyphenylene sulfide, polyethersulfone, polyimide, aromatic polyamide-aramid, and polytetrafluoroethylene; the nano-dispersant is selected from one or more of nano-silicon dioxide, nano-aluminum oxide, nano-titanium dioxide, nano-zinc oxide, nano-magnesium oxide, and nano-aluminum-doped zinc oxide; and the primary particle size of the nano-dispersant is between 5 and 100 nm; Wherein there is a temperature control device between the double-layer co-extrusion composite die head mold and the first guide roller; The temperature control device is an infrared lamp, which is arranged on both sides of the co-extruded composite intermediate film. The length of the infrared lamp covers the width of the co-extruded composite intermediate film. The voltage of the infrared lamp is 9V, the power is 1000-2000W, and the infrared wavelength is 800-1400nm. The distance between the infrared lamps on both sides of the co-extruded composite intermediate film is 50cm, the distance between the infrared lamp and the double-layer co-extruded composite die head is 200cm, and the distance between the infrared lamp and the first guide roller is 600cm. The temperature of the double-layer co-extrusion composite head mold is 300-340°C; the temperature of the temperature control device is 220-250°C; the temperature of the multiple guide rollers is lower than 200°C, and according to the processing direction, the temperature of the multiple guide rollers decreases successively, and the temperature difference between each guide roller is between 40-100°C; the number of the guide rollers is at least 2; through the winding machine traction, the traction rate is set to 25-35m / min, and the traction tension is set to 5-8N / m.

2. The method for preparing a PEEK double-layer co-extruded composite film according to claim 1, characterized in that: The melt index of the PEEK at 400°C and 2.16Kg load is in the range of 8-25g / 10min; The melt index of the heat-resistant engineering plastic at 380°C and 2.16Kg load is in the range of 5-17g / 10min; The total thickness of the PEEK double-layer co-extruded composite film is in the range of 0.4-0.5 mm, wherein the thickness of the first layer accounts for 50% of the total thickness of the PEEK double-layer co-extruded composite film.

3. The method for preparing a PEEK double-layer co-extruded composite film according to claim 1, characterized in that: The mixed material A is melt-blended and extruded by a first extruder, and the barrel temperature of the first extruder is set as follows according to the processing direction: the temperature of the heating zone 1 is 250-300° C., and the heating zones 2 to 9 are 320-380° C.; The mixed material B is melt-blended and extruded by a second extruder. The barrel temperature of the second extruder is set as follows according to the processing direction: the temperature of the heating zone 1 is 250-310° C., and the temperature of the heating zones 2 to 9 is 320-410° C., and the temperature is set according to the selected heat-resistant engineering plastic; The first extruder and the second extruder are set with the same screw speed and feeding frequency, the screw speed is 15-20rpm, and the feeding frequency is 7-9Hz; The temperature of the double-layer co-extrusion composite die head is 300-320°C.

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