A polyether ketone ketone-based cable insulation material and its preparation method

Abstract

The present invention discloses a cable insulating material based on polyether ketone ketone and a preparation method thereof. The preparation method is as follows: dissolve polyether ketone ketone in a solvent, extrude it onto a receiving belt close to a heating table, quickly preform it after constant temperature treatment by the heating table to form a polyether ketone ketone film; collect the obtained polyether ketone ketone film together with the receiving belt for winding; spread out the collected polyether ketone ketone film in a coagulating liquid to precipitate the residual solvent in the film, take it out, dry it, and then wind it again. The present invention fully dissolves polyether ketone ketone with a fluorine-based or chlorine-based polar solvent, and then obtains a cable insulating material through processes such as extrusion, spreading, precipitation, and coagulation. The preparation method is simple, avoiding the deficiencies of high melting temperature, large melt viscosity, and easy damage to properties in the preparation by the melting method. The prepared polyether ketone ketone insulating material has a density of 0.9-1.1 g / cm 3 , and the strength reaches 40-60 MPa, and it can be stably used at 300 °C for a long time.

Description

Technical Field

[0001] The present invention relates to a polyether ketone ketone lightweight high-temperature resistant cable insulating material and a preparation method thereof, belonging to the technical field of special engineering plastic films. Background Art

[0002] Benefiting from the rapid development of global civil aircraft, military aircraft, satellites, manned spaceflight and other industries, the demand for aerospace wires and cables globally continues to rise. Cables need to possess properties such as light weight, high temperature resistance, corrosion resistance, radiation resistance, flame retardancy, and anti-aging, posing higher requirements for the materials used in the insulating layer and protective layer. Existing cable insulating layers are mainly made of fluorine-containing materials such as irradiated cross-linked ethylene-tetrafluoroethylene, polytetrafluoroethylene, and perfluoroethylene propylene. The mass density of these materials is generally between 2.1 and 2.3 g / cm 3 It is difficult to further lighten the weight. In addition, high-end fluorine-containing cable materials also have defects such as high technical barriers and high manufacturing difficulty, which are prone to cause problems such as product defects and poor performance stability, and the long-term stable use temperature is difficult to reach above 250 °C, unable to meet the working requirements at higher temperatures.

[0003] Currently, the cable insulating layer is usually made by extrusion coating of polytetrafluoroethylene and processed using irradiation cross-linking technology. The corresponding products have a large outer diameter, high mass, and low temperature resistance grade, unable to meet the stringent use requirements of the cable. Another technology is to wind a polytetrafluoroethylene film around the conductor and form an insulating layer after high-temperature sintering. The insulating layer prepared by this method has defects such as easy cracking and unreliable sintering between layers. Therefore, in view of the performance requirements of lightweight and high-temperature resistance of the cable, it is urgent to develop higher-performance cable insulating layer materials.

[0004] Polyaryletherketone polymers have the highest heat resistance level among special engineering plastics and possess advantages such as low density, high temperature resistance, electrical insulation, and chemical corrosion resistance. Since polyaryletherketone polymers are generally difficult to dissolve, and their melting temperature is high and melt viscosity is large, the development of polyaryletherketone films faces challenges, thus limiting their use in the high-end cable field. Although there are currently a few related technologies for preparing insulating films or cable insulation layers by melt extrusion (such as: US PCT patent US2020 / 053028 (Chinese invention patent application 202080082015.0); Literature 1: W.L. Li, G.B. Wang, Z.H. Jiang, C. Liu, P.F. Huo, S.L. Zhang. Preparation and characterization of high-strength poly(ether ether ketone) films. J. Appl. Polym. Sci., 2014, 131(9), 40172; Literature 2: Sun Jianghua, Zhang Min. Study on the properties of polyetheretherketone films. China Plastics, 2020, 34(2), 43), they have not been widely used in industrial applications. Polyetherketoneketone (density 1.28 - 1.31 g / cm 3 ) As one of the important members of polyaryletherketone polymers, due to the rich ketone bonds, it has a relatively high molecular polarity and thus exhibits certain solubility, bringing the possibility of wet processing based on solution. Therefore, it is expected to develop polyetherketoneketone film materials based on solution methods and then prepare cable insulation layers.

[0005] At present, although there are already some related technologies for developing polyaryletherketone films based on dissolution strategies, there are still many problems and it is difficult to achieve stable and continuous preparation. For example: (1) US PCT patent US2012 / 037893 (Chinese invention patent 201280026566.0) dissolves polyaryletherketone in dichloromethane, toluene, dichloroethane, ethyl acetate, trifluoroacetic acid or a mixture thereof to form a viscous substance, and coats it on glass, a polymer film, a metal sheet or a silicon wafer and dries it into a film. However, many of the solvents used in this patent cannot truly dissolve polyetheretherketone or polyetherketoneketone, so the vague term "viscous substance" is used to describe this mixture in the patent. In addition, this patent uses a casting method to coat the so-called viscous substance on a substrate and obtains a film by drying means, and it is difficult to accurately control the film thickness and area. It can be seen that this patent fails to solve the dissolution problem of polyaryletherketone, especially polyetherketoneketone, and cannot achieve continuous and controllable preparation of polyaryletherketone films. (2) Chinese invention patent ZL201610181199.1 sulfonates polyaryletherketone by adding sulfonating agents such as concentrated sulfuric acid, fuming sulfuric acid, sulfur trioxide, chlorosulfonic acid, etc., and methylates polyaryletherketone by adding chloromethylating agents such as chloromethyl methyl ether, chloromethyl ethyl ether, formaldehyde / hydrochloric acid, chloromethyl ether, etc., and then dissolves it in N-methylpyrrolidone and forms a film by a casting method or a casting method. The obtained polyaryletherketone film needs to be subjected to a polymerization reaction in a quaternary ammonium reagent for 10-25 h, and there will still be residual acid in the film after that, and repeated washing is needed to promote neutralization. The preparation process of this patent is cumbersome and complex, and it is difficult to apply industrially. (3) Chinese invention patent application 201811029652.2 discloses a preparation method of a polyetherketoneketone membrane material, which dissolves polyaryletherketone in N-methylpyrrolidone at 100-200 °C, and spreads the solution on a glass plate and dries it in vacuum, and heat-treats it at 300-380 °C to obtain a polyetherketoneketone membrane. The solvents involved in this patent cannot achieve sufficient dissolution at room temperature, and the heat treatment temperature is close to or reaches the melting point of polyetherketoneketone, and there is still great difficulty in preparing the film. (4) Chinese invention patent application 201811029653.7 dissolves polyetherketoneketone and polyethersulfone in a certain proportion in one or a mixture of monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, or one or a mixture of dichloromethane, dichloroethane, toluene. The mixed solution is deposited on glass, a metal sheet or tin foil by a casting method, and reaches the melting point of polyetherketoneketone and cools through three temperature increases to form a composite membrane, and then the composite membrane is repeatedly washed with one or more of dichloromethane, dichloroethane, N-methylpyrrolidone, dimethylformamide, dimethylacetamide, etc. to dissolve polyethersulfone to obtain a high-porosity polyetherketoneketone battery membrane. The film formation process of this patent still requires a high temperature of 330-380 °C, so it can be seen that this patent has not solved the technical problem of film formation at high temperature.(5) The US PCT patent US2018 / 052368 (Chinese invention patent application 201880063292.X) dissolves polyaryletherketone polymers in 4-chloro-2-methylphenol, 4-chloro-3-methylphenol, 3-chlorophenol, 4-chlorophenol or 4-methylphenol at 50 - 100 °C, and coats the polyaryletherketone solution on a metal wire to form an insulating film. This patent cannot achieve complete dissolution of the polymer, so it is also called "paste". In addition, after the metal wire is impregnated, it still needs to be dried at 250 - 420 °C to evaporate the residual solvent and form an insulating layer, which fails to avoid the technical problems of high-temperature processing and has high preparation energy consumption. (6) The US PCT patent US2020 / 053028 (Chinese invention patent application 202080082015.0) proposes a method of melting and extruding polyaryletherketone to prepare an insulating film and winding it into an insulating layer, which can be applied to electromagnetic wires, motors, etc. However, the high melting point makes it difficult to extrude and form a film of polyetherketoneketone. (7) Chinese invention patent application 202110134071.0 dissolves polyetherketoneketone in concentrated sulfuric acid to form a solution with a concentration of 1 - 20 w / v%, casts it on a glass plate, then places it in a coagulating liquid for coagulation at a certain temperature, and forms a film after washing, drying and heat treatment (300 - 380 °C). The preparation process of this patent is prone to cause sulfonation of polyetherketoneketone, and the film forming still requires high-temperature treatment. (8) Chinese invention patent application 202211009079.5 fully dissolves sulfonated polyetheretherketone in a solvent, adds double-functionalized montmorillonite with surface-grafted sulfonic acid groups, and then uniformly distributes the dispersed solution on a clean glass plate for casting film formation. After drying, a sulfonated polyetheretherketone composite film is obtained, but its application at high temperatures is limited after sulfonation. (9) Chinese invention patent ZL202010600489.1 dissolves sulfonated polyetheretherketone and polyvinylidene fluoride in N-methylpyrrolidone respectively, mixes them evenly, pours them into a polytetrafluoroethylene mold, and obtains a sulfonated polyetheretherketone / polyvinylidene fluoride composite film through vacuum drying, which can be used as an ion exchange membrane, but cannot be used at high temperatures. (10) Chinese invention patent ZL202211328194.9 obtains black phosphorus-modified polyetherketoneketone powder by ball milling black phosphorus into polyetherketoneketone, then mixes it with polyetherimide and adds calcium carbonate powder, aluminate coupling agent, compatibilizer, antioxidant, light stabilizer and lubricant for mixing and stirring. Finally, the mixed material is melt-extruded and granulated to obtain a high-temperature resistant cable material. This patent requires melt extrusion for granulation, and it is impossible to avoid performance damage caused by high temperature. In summary, there are still many difficulties and deficiencies in realizing the preparation of polyetherketoneketone films and applying them to the cable field.

[0006] In recent years, Chinese invention patents ZL202111055042.1, 202111401064.9, and 202210401927.0 have developed related technologies for preparing high-performance carbon fiber composites and polyether ketone ketone (PEKK) fibers by non-destructively dissolving PEKK using fluorine-based or chlorine-based polar solvents, breaking through the key technology of high-concentration dissolution of PEKK at room temperature (25°C) (which can reach 22 wt%). Therefore, it is expected to develop a film preparation technology with uniform thickness, adjustable width, and continuous stability using PEKK solution, and develop a lightweight high-temperature resistant cable insulation material.

[0007] The high melting temperature and large melt viscosity of PEKK result in easy blockage during melt extrusion, and long-term high-temperature treatment will damage the material properties; while using the solution method to prepare PEKK film also has problems such as difficult full dissolution with conventional solvents, easy solvent volatilization during high-temperature dissolution, some solvents are prone to cause sulfonation of PEKK, and the film-forming process is discontinuous and the step of high-temperature shaping cannot be avoided. Therefore, it is difficult to stably prepare PEKK film in the prior art, and there are difficulties in preparing cables based on PEKK film. Summary of the Invention

[0008] The technical problem to be solved by the present invention is to provide a preparation method that can stably obtain PEKK film.

[0009] To solve the above technical problems, the present invention provides a preparation method of a cable insulation material based on PEKK, including the following steps:

[0010] Step 1): At room temperature, dissolve PEKK in a solvent to obtain a uniform PEKK solution;

[0011] Step 2): Extrude the PEKK solution obtained in Step 1 onto a receiving belt close to a heating table, and the receiving belt continuously runs driven by a rotating roller; the extruded PEKK solution is spread on the receiving belt by extrusion and quickly preformed after constant-temperature treatment by the heating table to form a PEKK film;

[0012] Step 3): Collect and wind up the PEKK film obtained in Step 2 together with the receiving belt;

[0013] Step 4): Spread out the PEKK film collected in Step 3 in a coagulating liquid to precipitate the remaining solvent in the film, take it out, dry it at room temperature, and then wind it up again to finally obtain a cable insulation material based on PEKK.

[0014] Preferably, for the PEKK in Step 1), the molar ratio of the para-position structure to the ortho-position structure is 50:50 to 100:0, preferably 50:50, 60:40, 70:30, 80:20, or 100:0; the PEKK uses powder with a particle size ≤ 300 μm.

[0015] Preferably, the solvent in step 1) is any one of fluoro-based or chloro-based polar solvents, or a mixed solvent of any one of fluoro-based and chloro-based polar solvents and dichloroethane; the mass concentration of the obtained polyether ketone ketone solution is 5-18%, preferably 10-15%.

[0016] More preferably, the fluoro-based or chloro-based polar solvent is specifically trifluoroacetic acid, 3,3,3-trifluoro-2,2-dimethylpropanoic acid, p-chlorophenol, dichloroacetic acid or dichloropropanoic acid, preferably trifluoroacetic acid or a mixed solvent of trifluoroacetic acid and dichloroethane, and the mass content of dichloroethane in the mixed solvent is not more than 30%.

[0017] Preferably, the dissolution process conditions in step 1) are: stirring for 6-24 h under the conditions of 25-50 °C and 1200-1800 rpm.

[0018] Preferably, the receiving belt in step 2) is a polytetrafluoroethylene film or a polyimide film; the width of the receiving belt is 0.5-2 cm; the temperature of the heating table is 50-80 °C; during the spreading process, a straight rod is used to extrude the solution to spread it out.

[0019] Preferably, the winding speed in step 3) is 0.6-1 m / min.

[0020] Preferably, the coagulating liquid in step 4) is absolute ethanol, deionized water or a mixed liquid of the two, preferably a mixed solution of ethanol and deionized water with a mass ratio of 3:1; the precipitation time is 12-48 h, preferably 24 h.

[0021] The present invention also provides a cable insulating material prepared by the preparation method of the above-mentioned cable insulating material based on polyether ketone ketone.

[0022] More preferably, the cable insulating material is transparent, with a thickness of 20-30 μm, a density of 0.9-1.1 g / cm3, a strength of 40-60 MPa, and is easy to separate from the receiving belt, facilitating subsequent use.

[0023] Compared with the prior art, the present invention has the following beneficial effects:

[0024] (1) The present invention can effectively and non-destructively dissolve polyether ketone ketone in fluoro-based or chloro-based polar solvents at room temperature, and realize the stable and continuous preparation of polyether ketone ketone lightweight high-temperature resistant cable insulating materials.

[0025] (2) The polyether ketone ketone film (density 0.9-1.1 g / cm 3 ) prepared by the present invention compared with the polytetrafluoroethylene film (density 2.1-2.3 g / cm 3 ) commonly used in cable insulating materials, the density is reduced by nearly 50%.

[0026] (3) The process flow provided by the present invention is simple. The film can be quickly preformed by drying on a heating table (50 - 80 °C). The film forming avoids the high-temperature process, and the polyether ketone ketone film has good mechanical properties, with a strength of 40 - 60 MPa. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a flow chart of the preparation method provided by the present invention;

[0028] Figure 2 is a schematic diagram of the equipment used in each embodiment;

[0029] Figure 3 is Figure 2 a top view of;

[0030] Figure 4 is a photo of the polyether ketone ketone film obtained in step 3 of Example 1;

[0031] Figure 5 is a scanning electron microscope image of the polyether ketone ketone insulating material prepared in Example 1;

[0032] Figure 6 is a thermogravimetric test curve of the polyether ketone ketone insulating material prepared in Example 1 in a nitrogen environment;

[0033] Figure 7 is a cross-sectional view of the cable after winding and heat treatment of the polyether ketone ketone insulating material obtained in Example 1. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To make the present invention more obvious and understandable, preferred embodiments are provided below in conjunction with the accompanying drawings for detailed description as follows.

[0035] The devices used in each embodiment are as Figure 2 、 3 shown. It includes a syringe 1 disposed above the right side of the heating table 4. The tabletop of the heating table 4 is covered with a receiving belt 3. A pair of rollers 2 are provided on both sides of the heating table 4. The right roller 2 unrolls the receiving belt 3, and the left roller 2 collects the receiving belt 3 extruded with the polyether ketone ketone film (see the rotation direction of the roller 2 in Figure 2 ); The freshly extruded polyether ketone ketone solution is spread under the extrusion of a glass rod 5.

[0036] Example 1

[0037] This example provides a method for continuously and stably preparing a polyether ketone ketone lightweight high-temperature resistant cable insulating material. The preparation process is as Figure 1 shown and includes the following steps:

[0038] Step 1: Dissolve 10 g of polyether ketone ketone powder (the molar ratio of para-position structure to ortho-position structure, denoted as T / I ratio is 50:50) in a mixed solution of 90 g of trifluoroacetic acid and dichloroethane. The mass ratio of the mixed solution of trifluoroacetic acid and dichloroethane is 7:3, and stir with a magnetic stirrer (rotation speed 1500 rpm) at room temperature for 8 h to obtain a polyether ketone ketone solution with a concentration of 10 wt%.

[0039] Step 2: At room temperature, extrude the polyether ketone ketone solution onto the surface of a polytetrafluoroethylene receiving tape placed on a heating table through a flat-mouth needle. Among them, the flat mouth of the flat-mouth needle is 5 mm long and 1 mm wide, the flat-mouth needle is 2 mm away from the surface of the polytetrafluoroethylene receiving tape, the extrusion rate of the polyether ketone ketone solution is 1.6 mL / min, the set temperature of the heating table is 60 °C, and the width of the polytetrafluoroethylene receiving tape is 2 cm and the thickness is 0.1 mm.

[0040] Step 3: The polyether ketone ketone solution is spread on the receiving tape by extrusion with a glass rod. After the receiving tape passes through the heating table, a preformed polyether ketone ketone film is formed on the surface, as Figure 2 、 3 shown.

[0041] Step 4: Collect the preformed polyether ketone ketone film through a winding device, and the winding speed of the rotating roller is 0.6 m / min.

[0042] Step 5: Place the above-mentioned preformed polyether ketone ketone film in a 75% ethanol solution and solidify for 24 h to completely precipitate the solvent in the polyether ketone ketone film. The solidified polyether ketone ketone film is collected through a rotating roller. Take part of the polyether ketone ketone film after solidification and drying for scanning electron microscopy (SEM) and thermogravimetric (TG) characterization analysis. The surface of the film is as Figure 4 、 5 shown; the TG analysis of the film is as Figure 6 shown.

[0043] Example 2

[0044] This example provides a method for continuously and stably preparing a polyether ketone ketone lightweight high-temperature resistant cable insulating material, including the following steps:

[0045] Step 1: Dissolve 13 g of polyether ketone ketone powder (T / I ratio is 60:40) in 87 g of a trifluoroacetic acid-dichloroethane mixed solution. The mass ratio of the mixed solution of trifluoroacetic acid and dichloroethane is 4:1, and stir with a magnetic stirrer (rotation speed 1500 rpm) at room temperature for 8 h to obtain a polyether ketone ketone solution with a concentration of 13%.

[0046] Step 2: Extrude the polyether ketone ketone solution through a flat-tip needle onto the surface of a polytetrafluoroethylene receiving tape placed on a heating table at room temperature. Among them, the flat tip of the flat-tip needle is 3 mm long and 0.6 mm wide, the flat-tip needle is 2 mm away from the surface of the polytetrafluoroethylene receiving tape, the extrusion rate of the polyether ketone ketone solution is 0.7 mL / min, the set temperature of the heating table is 70 °C, and the width of the polytetrafluoroethylene receiving tape is 1 cm and the thickness is 0.1 mm.

[0047] Step 3: The same as Step 3 in Example 1.

[0048] Step 4: The same as Step 4 in Example 1, except that the winding speed of the roller is 0.8 m / min.

[0049] Step 5: The same as Step 5 in Example 1, except that the selected coagulating liquid is ethanol and the coagulation time is 24 h.

[0050] Example 3

[0051] This example provides a method for continuously and stably preparing a polyether ketone ketone lightweight high-temperature resistant cable insulating material, which includes the following steps:

[0052] Step 1: Dissolve 7 g of polyether ketone ketone powder (T / I ratio is 7:3) in 93 g of trifluoroacetic acid solution, and stir with a magnetic stirrer (rotation speed 1500 rpm) for 6 h at room temperature to obtain a 7 wt% polyether ketone ketone solution.

[0053] Step 2: The same as Step 2 in Example 1, except that the set temperature of the heating table is 80 °C and the extrusion rate of the polyether ketone ketone solution is 1.8 mL / min.

[0054] Step 3: The same as Step 3 in Example 1.

[0055] Step 4: The same as Step 4 in Example 1, except that the winding speed of the roller is 0.8 m / min.

[0056] Step 5: The same as Step 5 in Example 1, except that the used coagulating liquid is deionized water, the drying temperature is 80 °C, and the time is 2 h.

[0057] Example 4

[0058] This example provides a method for continuously and stably preparing a polyether ketone ketone lightweight high-temperature resistant cable insulating material, which includes the following steps:

[0059] Step 1: Dissolve 5 g of polyether ketone ketone powder (T / I ratio is 50:50) in 95 g of trifluoroacetic acid solution, and stir with a magnetic stirrer (rotation speed 1500 rpm) for 8 h at room temperature to obtain a 5 wt% polyether ketone ketone solution.

[0060] Step 2: The same as Step 2 in Example 1, except that the temperature of the heating table is 90 °C and the extrusion rate of the polyether ketone ketone solution is 1.7 mL / min.

[0061] Steps 3-5: The same as Steps 3-5 in Example 1.

[0062] Example 5

[0063] This example provides a method for continuously and stably preparing a polyether ketone ketone lightweight high-temperature resistant cable insulation material, which includes the following steps:

[0064] Step 1: Dissolve 15 g of polyether ketone ketone powder (T / I ratio is 50:50) in 85 g of a mixed solution of trifluoroacetic acid and dichloroethane. The mass ratio of the trifluoroacetic acid to dichloroethane mixed solution is 7:3, and stir with a magnetic stirrer (rotation speed 1500 rpm) at room temperature for 8 h to obtain a 5 wt% polyether ketone ketone solution.

[0065] Steps 2-4: The same as Steps 2-4 in Example 1.

[0066] Step 5: The same as Step 5 in Example 1, except that the coagulating liquid is a 50% ethanol solution and the coagulation time is 24 h.

[0067] Example 6

[0068] This example provides a method for continuously and stably preparing a polyether ketone ketone film, which includes the following steps:

[0069] Step 1: Dissolve 10 g of polyether ketone ketone powder (T / I ratio is 50:50) in 90 g of trifluoroacetic acid solution, and stir with a magnetic stirrer (rotation speed 1500 rpm) at room temperature for 8 h to obtain a 10 wt% polyether ketone ketone solution.

[0070] Step 2: The same as Step 2 in Example 1, except that the temperature of the heating table is 50 °C.

[0071] Step 3: The same as Step 3 in Example 1.

[0072] Step 4: The same as Step 4 in Example 1, except that the winding speed of the roller is 1 m / min.

[0073] Step 5: The same as Step 5 in Example 1.

[0074] Performance test:

[0075] The polyether ketone ketone film prepared by steps 1 to 3 of the above embodiments was solidified with 75% ethanol, the solvent was precipitated, and after drying at 60 °C for 3 h, performance tests were carried out. Among them, conductive silver paste was coated on both sides of the film, and the insulation was detected with a multimeter after drying; the film was cut into strips of 1×3 cm for tensile testing, and the tensile speed was 0.1 mm / min. The results are shown in Table 1. The film was subjected to differential scanning calorimetry (DSC) and TG tests, and the results are shown in Table 1.

[0076] Table 1 Performance test results of polyether ketone ketone film

[0077] Film thickness / μm Film insulation Tensile strength / MPa Thermogravimetric temperature / °C Example 1 22 Insulation 57.6 544 Example 2 30 Insulation 53.3 552 Example 3 38 Insulation 54.1 556 Example 4 4 Insulation 46.5 545 Example 5 42 Insulation 52.8 545 Example 6 15 Insulation 47.4 544

[0078] It can be seen from the results in Table 1 that the prepared film has good mechanical properties and excellent thermal properties.

[0079] Taking the polyether ketone ketone film obtained in Example 1 as an example, the conductor was wrapped, and the finished cable was tested as follows:

[0080] (1) Interlayer adhesion: Observe the adhesion of the cable insulation layer under an electron microscope. The results show good interlayer adhesion, as Figure 7 shown.

[0081] (2) High-temperature resistance test: Take a section of the wrapped cable after hot pressing treatment and treat it in a muffle furnace at 300 °C for 6 h, and observe whether there are cracks on the cable surface. The results show that the insulation layer on the cable surface does not crack.

[0082] (3) High-temperature insulation test: Strip 1 cm of the insulation layer at both ends of the cable, and use a megohmmeter to test the cable insulation in an environment of 300 °C. The results show that the cable is insulated at the 2500 V gear; after being treated at 300 °C for 6 h, it is still insulated.

[0083] The polyether ketone ketone film obtained by the above method has the advantages of light weight, insulation, high temperature resistance, high strength, etc., and can be well applied to lightweight high-temperature cables. For this reason, the obtained polyether ketone ketone film can be wrapped around the conductor to prepare a cable insulation layer. The specific method is as follows: (1) The polyether ketone ketone film is tightly wrapped around the conductor to form an insulation layer with a thickness of 100-130 μm; (2) The wrapped cable is preheated at 360-400 °C for 0.5-1 h; (3) The wrapped cable is extruded at 360-400 °C through a circular pressure roller to bond the insulation layer to form a cable insulation layer.

Claims

1. A preparation method of a polyether ketone ketone-based cable insulating material, characterized in that It includes the following steps: Step 1): At room temperature, dissolve polyether ketone ketone in a solvent to obtain a uniform polyether ketone ketone solution; Step 2): Extrude the polyether ketone ketone solution obtained in Step 1) onto a receiving belt close to a heating table. The receiving belt continuously runs driven by a rotating roller; the extruded polyether ketone ketone solution is spread on the receiving belt by extrusion and quickly preformed after being treated at a constant temperature on the heating table to form a polyether ketone ketone film; the temperature of the heating table is 50 - 80°C; during the spreading process, a straight rod is used to extrude the solution to spread it out; Step 3): Collect and wind up the polyether ketone ketone film obtained in Step 2) together with the receiving belt; Step 4): Unroll the polyether ketone ketone film collected in Step 3) and place it in a coagulating liquid to precipitate the remaining solvent in the film. Take it out, dry it at room temperature, and then wind it up again to finally obtain a cable insulating material based on polyether ketone ketone.

2. The preparation method of the polyether ketone ketone-based cable insulating material according to claim 1, characterized in that, For the polyether ketone ketone in Step 1), the molar ratio of the para - phenyl structure to the ortho - phenyl structure is 50:50 - 100:0; the polyether ketone ketone uses powder with a particle size ≤ 300μm.

3. The preparation method of the polyetherketoneketone-based cable insulating material according to claim 1, wherein The solvent in Step 1) is any one of fluorine - based or chlorine - based polar solvents, or a mixed solvent of any one of fluorine - based and chlorine - based polar solvents and dichloroethane; the mass concentration of the obtained polyether ketone ketone solution is 5 - 18%.

4. The preparation method of the polyether ketone ketone-based cable insulating material according to claim 3, wherein The specific fluorine - based or chlorine - based polar solvent is trifluoroacetic acid, 3,3,3 - trifluoro - 2,2 - dimethylpropanoic acid, p - chlorophenol, dichloroacetic acid or dichloropropanoic acid.

5. The preparation method of the polyetherketoneketone-based cable insulating material according to claim 1, characterized in that, The dissolution process conditions in Step 1) are: stir for 6 - 24h under the conditions of 25 - 50°C and 1200 - 1800 rpm.

6. The preparation method of the polyether ketone ketone-based cable insulating material according to claim 1, characterized in that, The receiving belt in Step 2) is a polytetrafluoroethylene film or a polyimide film; the width of the receiving belt is 0.5 - 2 cm.

7. The preparation method of the polyether ketone ketone-based cable insulating material according to claim 1, wherein, The winding - up speed in Step 3) is 0.6 - 1 m / min.

8. The preparation method of the polyether ketone ketone-based cable insulating material according to claim 1, characterized in that The coagulating liquid in Step 4) is anhydrous ethanol, deionized water or a mixture of the two; the precipitation time is 12 - 48h.

9. A cable insulating material prepared by the preparation method of the cable insulating material based on polyether ketone ketone according to any one of claims 1 - 8.

10. The cable insulating material according to claim 9, wherein The cable insulation material is transparent, with a thickness of 20 to 30 μm and a density of 0.9 to 1.1 g / cm 3 , and the strength is 40 to 60 MPa.

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