Polyurethane composite material, preparation method thereof and cable containing polyurethane composite material

Abstract

The invention belongs to the field of polyurethane materials, and particularly discloses a polyurethane composite material, a preparation method thereof and a cable containing the polyurethane composite material. The titanium dioxide modified by aminated four-arm polyethylene glycol is used as an anti-aging component, the polyurethane matrix is subjected to fluorinated molecular structure modification, and the titanium dioxide and the polyurethane matrix are matched with each other, so that the damp-heat aging resistance and the mechanical property of the polyurethane composite material are improved, and the service life of the polyurethane composite material is prolonged. And the technical problem that the heat conduction, flame retardance and mechanical properties of the polyurethane composite material are reduced in a severe environment is also solved, so that the heat conduction, flame retardance and mechanical properties are kept stable for a long time.

Description

Technical Field

[0001] This invention belongs to the field of polyurethane materials, specifically relating to a polyurethane composite material, its preparation method, and a cable containing the same. Background Technology

[0002] High-voltage cables, as core components of power transmission networks, are widely used in urban power grids, inter-regional power transmission projects, and industrial facilities. Their long-term stable operation is directly related to the safety and reliability of the power system. However, the actual operating environment of high-voltage cables is extremely harsh. Long-term extreme temperature differences outdoors cause repeated thermal expansion and contraction of the filling material inside, accelerating molecular chain breakage and leading to cracking and aging. Furthermore, in humid and hot environments, the molecular chains are further hydrolyzed and oxidized, causing a decrease in their thermal conductivity and flame retardant properties. Simultaneously, ultraviolet radiation and ozone trigger photo-oxidation reactions, causing the filling material to yellow and accelerate aging and failure. This necessitates that high-voltage cable filling materials possess excellent aging resistance, flame retardancy, and thermal conductivity to ensure the safe and stable operation of the cable.

[0003] Polyurethane-based filler materials possess comprehensive aging resistance properties such as resistance to damp heat aging, resistance to high and low temperature cycling, resistance to ultraviolet oxidation, and resistance to chemical corrosion. Meanwhile, existing technologies generally improve aging resistance by adding antioxidants, ultraviolet absorbers, and hydrolysis-resistant modifiers to the filler materials. However, existing polyurethane composite materials have the following limitations: (1) Traditional antioxidants (such as hindered phenols) are easily volatilized at high temperatures, limiting their effectiveness in improving the long-term aging resistance of filler materials; (2) In general filler materials, aging-resistant additives are mostly present in a simple physical blending manner, which easily migrates and precipitates, leading to performance degradation of the material; (3) To meet the requirements of mechanical properties, thermal conductivity, and flame retardancy, a large amount of inorganic fillers (such as thermal conductive agents and flame retardants) need to be added to the filler materials. This exacerbates internal stress concentration, accelerating aging and cracking, resulting in a significant decrease in thermal conductivity, flame retardancy, and mechanical properties, failing to meet the actual aging resistance requirements of high-voltage cables operating in harsh environments for extended periods.

[0004] Therefore, it is still necessary to develop a polyurethane composite material that can maintain stable thermal conductivity, flame retardancy and mechanical properties in harsh environments for a long time. This is the key to solving the problem of safe operation of high-voltage cables and is of great significance to improving the reliability of power systems. Summary of the Invention

[0005] In view of the problems of polyurethane composite materials in the prior art being unable to maintain stable thermal conductivity, flame retardancy and mechanical properties (i.e., poor aging resistance) for a long time, the present invention will provide a polyurethane composite material, a method for preparing the same, and a cable containing the same.

[0006] To achieve the above objectives, the following technical solutions are specifically included: In a first aspect, the present invention provides a polyurethane composite material comprising the following components in parts by weight: 75-100 parts of fluorinated polyurethane, 3-15 parts of an anti-aging agent, 5-15 parts of a thermally conductive agent, and 5-20 parts of a flame retardant. The anti-aging agent comprises the following components in parts by weight: 0.1-3 parts of aminated tetra-arm polyethylene glycol-modified titanium dioxide, 0.1-5 parts of an antioxidant, and 0.1-10 parts of a light stabilizer. The fluorinated polyurethane is polymerized from isocyanate, fluorinated polyol, and amine chain extender.

[0007] In this invention, the polyurethane composite material comprises aminated four-arm polyethylene glycol-modified titanium dioxide, an antioxidant, and a light stabilizer, forming a composite anti-aging agent. The titanium dioxide in the aminated four-arm polyethylene glycol-modified titanium dioxide physically shields ultraviolet light, preventing photo-aging. The antioxidant inhibits oxidation reactions in thermal and photo-oxidation. The light stabilizer scavenge free radicals generated by photo-oxidation. These three agents work synergistically through multiple stages of "prevention-inhibition-scavenging," significantly improving the weather resistance, photo-aging resistance, and thermo-oxidative aging resistance of the polyurethane composite material. Furthermore, the hydroxyl and amino groups of the aminated four-arm polyethylene glycol on the modified titanium dioxide surface can undergo condensation reactions with the isocyanate groups on the polyurethane molecules, enhancing intermolecular interactions and forming a cross-linked entangled network structure between the modified titanium dioxide and the polyurethane matrix. This also provides a stable environment for the antioxidant and light stabilizer, reducing their migration or loss, further effectively improving the material's anti-aging performance and extending its service life.

[0008] Fluorinated polyurethane molecules are polymerized from isocyanates, fluorinated polyols, and amine chain extenders. The fluorinated polyols possess extremely low surface energy, reducing the damage to the internal structure caused by moisture penetration. High-energy fluorocarbon bonds enhance the high-temperature thermal stability of the polyurethane, while the strong electronegativity and chemical inertness of the fluorinated groups endow the polyurethane matrix with resistance to acids, alkalis, and solvents. The amine chain extenders contain multiple active amino groups that can react with isocyanate groups to form a three-dimensional cross-linked network, restricting excessive chain movement under high temperatures or external forces and reducing structural relaxation during aging. Furthermore, residual amino groups undergo hydrogen bonding or chemical reactions with the aminated four-arm polyethylene glycol on the modified titanium dioxide surface, promoting the uniform dispersion of anti-aging agents, thermal conductive agents, and flame retardants within the polyurethane matrix and preventing performance loss due to additive agglomeration.

[0009] Only a small amount of thermally conductive agent is needed to form a thermally conductive network in the fluorinated polyurethane matrix, which can quickly dissipate heat and reduce the heat accumulation of the material in high-temperature environments, thereby reducing the risk of degradation or combustion caused by local overheating and assisting in flame retardancy. The char layer formed by the flame retardant can still maintain a certain structure at high temperatures, which can protect the integrity of the thermally conductive network and prevent the flame from directly destroying the heat conduction path. The thermally conductive agent and the flame retardant are stable and will not have their thermal conductivity and flame retardancy properties decay due to temperature changes or aging. This synergy of "thermal conductivity-flame retardancy" ensures the heat dissipation and fire protection safety of the material during the long-term use of the cable.

[0010] This invention uses aminated four-arm polyethylene glycol-modified titanium dioxide as an aging-resistant component and modifies the molecular structure of the polyurethane matrix with fluorination. The two work together to not only improve the resistance to humid heat aging and mechanical properties of polyurethane composites, but also solve the technical problem of the decline in thermal conductivity and flame retardancy of polyurethane composites in harsh environments, thus ensuring that thermal conductivity and flame retardancy remain stable over a long period of time.

[0011] Preferably, the antioxidant includes at least one of hindered phenolic antioxidants and phosphite antioxidants.

[0012] More preferably, the hindered phenolic antioxidant includes at least one of pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate] (antioxidant 1010), octadecyl β-(3,5-di-tert-butyl-4-hydroxyphenyl)propionate (antioxidant 1076), and diethyl 3,5-di-tert-butyl-4-hydroxybenzylphosphonate (antioxidant 1098); the phosphite antioxidant includes at least one of tris[2,4-di-tert-butylphenyl] phosphite (antioxidant 168), bis(2,4-di-tert-butylphenyl) pentaerythritol diphosphite (antioxidant 626), and trioctyl phosphite (TOP).

[0013] Preferably, the light stabilizer includes hindered amine light stabilizers.

[0014] More preferably, the hindered amine light stabilizer includes at least one of bis-2,2,6,6-tetramethylpiperidinol sebacate (light stabilizer 770), tetrakis(2,2,6,6-tetramethyl-4-piperidinyl)1,2,3,4-butanetetracarboxylate (light stabilizer 622), and poly(2,2,6,6-tetramethyl-4-piperidinyl) sebacate (light stabilizer 123).

[0015] Preferably, the mass ratio of the aminated tetra-arm polyethylene glycol-modified titanium dioxide, antioxidant, and light stabilizer is 1:(1-5):(1-6).

[0016] More preferably, the mass ratio of the aminated tetra-arm polyethylene glycol-modified titanium dioxide, antioxidant, and light stabilizer is 1:(1.5-2.5):(3-5).

[0017] Preferably, the isocyanate includes at least one of alicyclic isocyanates, phenyl isocyanates, and alkyl isocyanates.

[0018] More preferably, the isocyanate comprises an alicyclic isocyanate. The alicyclic group can prevent oxidative discoloration or molecular chain breakage caused by ultraviolet radiation, thereby reducing the performance degradation of the material due to photoaging at its source.

[0019] Preferably, the isocyanate comprises at least one selected from cyclohexylmethane diisocyanate (HMDI), diphenylmethane diisocyanate (MDI), toluene diisocyanate (TDI), and hexamethylene diisocyanate (HDI). Preferably, the fluorinated polyol comprises at least one selected from perfluoropolyether diol, fluorinated polyepoxybutane polyol, or perfluorodecanediol.

[0020] Preferably, the amine chain extender includes at least one of diethylenetriamine, 3,5-diethyltoluenediamine, polyoxypropylenetriamine, and isophoronediamine.

[0021] Preferably, the mass ratio of the isocyanate, fluorinated polyol and amine chain extender is (5-15):(1-5):1.

[0022] Preferably, the thermally conductive agent includes at least one of alumina, boron nitride, or aluminum nitride. These highly thermally conductive inorganic fillers exhibit excellent chemical stability and do not react chemically with the matrix; therefore, their thermal conductivity will not decrease due to temperature changes or aging.

[0023] Preferably, the flame retardant includes at least one of ammonium polyphosphate, melamine cyanurate, or zinc borate. The char layer formed by the above flame retardant can maintain a certain structure at high temperatures, protecting the integrity of the heat conduction network and preventing the flame from directly damaging the heat conduction path; moreover, the above flame retardant has excellent chemical properties and its flame retardant performance will not decrease due to temperature changes or aging.

[0024] More preferably, the flame retardant comprises ammonium polyphosphate, melamine cyanurate, and zinc borate, wherein the mass ratio of ammonium polyphosphate, melamine cyanurate, and zinc borate is 1:(1-5):(1-2).

[0025] Secondly, the present invention provides a method for preparing the polyurethane composite material, comprising the following steps: S1. In an organic solvent, isocyanate, fluorinated polyol and amine chain extender undergo a polymerization reaction to obtain the fluorinated polyurethane; S2. In an organic solvent, titanium dioxide and aminated tetra-armed polyethylene glycol undergo a surface modification reaction, followed by washing and drying to obtain the aminated tetra-armed polyethylene glycol-modified titanium dioxide. S3. Mix the aminated tetra-armed polyethylene glycol-modified titanium dioxide, antioxidant, and light stabilizer to obtain the anti-aging agent; S4. Mix the fluorinated polyurethane, the anti-aging agent, the flame retardant, and the thermal conductive agent evenly to obtain the polyurethane composite material.

[0026] Preferably, in step S1, the mass ratio of the isocyanate, fluorinated polyol and amine chain extender is (5-15):(1-5):1.

[0027] Preferably, in step S1, the organic solvent includes N,N-dimethylformamide.

[0028] Preferably, in step S1, the polymerization reaction temperature is 60-75°C, and the polymerization reaction time is 4-8 hours.

[0029] Preferably, in step S1, the mass concentration of the amine chain extender in the organic solvent is 50-100 g / L.

[0030] Preferably, in step S2, the mass ratio of titanium dioxide to aminated tetraarm polyethylene glycol is 1:(0.5-2).

[0031] Preferably, in step S2, the temperature of the surface modification reaction is 80-100℃, and the time of the surface modification reaction is 6-10h.

[0032] Preferably, in step S2, the organic solvent includes N,N-dimethylformamide.

[0033] Preferably, in step S2, the surface modification reaction is carried out under the protection of an inert gas, which includes at least one of nitrogen, argon, or helium.

[0034] Thirdly, the present invention provides a cable comprising the aforementioned polyurethane composite material.

[0035] The polyurethane composite material of the present invention has high mechanical properties, thermal conductivity and flame retardancy, as well as excellent aging resistance, which makes its mechanical properties, thermal conductivity and flame retardancy stable in harsh environments such as humid heat for a long time. It is very suitable as a filler material for cables, which can significantly improve the service life, safety and reliability of cables.

[0036] Compared with the prior art, the present invention has the following beneficial effects: The present invention uses aminated tetra-arm polyethylene glycol modified titanium dioxide as an aging resistant component and modifies the molecular structure of the polyurethane matrix with fluorination. The two work together to not only improve the resistance to humid heat aging and mechanical properties of polyurethane composites, but also solve the technical problems of the decline in thermal conductivity, flame retardancy and mechanical properties of polyurethane composites in harsh environments, so that the thermal conductivity, flame retardancy and mechanical properties remain stable for a long time. Detailed Implementation

[0037] To better illustrate the purpose, technical solution, and advantages of this invention, specific embodiments will be used to further explain the invention below. Unless otherwise specified, the test methods used in the embodiments and / or comparative examples are conventional methods; the materials and reagents used, unless otherwise specified, are commercially available.

[0038] Examples 1-19 A method for preparing a polyurethane composite material includes the following steps: S1. Preparation of fluorinated polyurethane: Mix 50g of dicyclohexylmethane diisocyanate, 25g of fluorinated polyol, 10g of diethylenetriamine and 150mL of N,N-dimethylformamide evenly, and stir at 60-75℃ for 4-8 hours to carry out the polymerization reaction to obtain fluorinated polyurethane solution. S2. Preparation of anti-aging agent: Weigh 10g of titanium dioxide, and weigh the aminated tetra-arm polyethylene glycol according to the mass ratio of titanium dioxide to aminated tetra-arm polyethylene glycol of 1:(0.5-2). Then add titanium dioxide and aminated tetra-arm polyethylene glycol to 100mL of N,N-dimethylformamide. Under nitrogen protection, stir at 80-100℃ for 6-10 hours to carry out surface modification reaction. After centrifugation, washing, and vacuum drying, modified titanium dioxide is obtained. S3. Mix 5g of modified titanium dioxide, antioxidant 1010 and light stabilizer 770 in a mass ratio of 1:(1-5):(1-6) to obtain an anti-aging agent. S4. Preparation of flame retardant and thermal conductive agent: Mix ammonium polyphosphate, melamine cyanurate and zinc borate with a total weight of 10g in a mass ratio of 1:(1-5):(1-2) to obtain flame retardant; Prepare alumina, boron nitride, and aluminum nitride for later use; S5. Preparation of polyurethane composite material: Mix 80 parts by weight of fluorinated polyurethane solution, 5 parts by weight of anti-aging agent, 10 parts by weight of thermal conductive agent and 10 parts by weight of flame retardant evenly to obtain polyurethane composite material. The raw materials and their amounts used in Examples 1-19, as well as the reaction times and temperatures involved in the preparation process, are detailed in Table 1.

[0039] Comparative Example 1 The difference between this comparative example and Example 2 is that in step S1, this comparative example uses polytetrahydrofuran ether diol (non-fluorinated) to replace fluorinated polyepoxybutane polyol by mass to prepare polyurethane (fluorine-free), while the rest are the same.

[0040] Comparative Example 2 The difference between this comparative example and Example 2 is that step S2 is not performed in this comparative example, and titanium dioxide is not added; otherwise, they are the same.

[0041] Comparative Example 3 The difference between this comparative example and Example 2 is that this comparative example does not perform the modification reaction in step S2, and uses unmodified titanium dioxide of equal mass to replace the modified titanium dioxide; otherwise, they are the same.

[0042] Performance testing: The polyurethane composite materials prepared in the examples and comparative examples were placed in a constant temperature and humidity test chamber at 85°C and 85% humidity for 7 days to test the thermal conductivity, flame retardancy, and mechanical properties of the polyurethane composite materials before and after aging. The test results are shown in Table 2.

[0043] The thermal conductivity of the aging-resistant, thermally conductive, and flame-retardant polyurethane composite material was tested in accordance with the standard GB / T42919.4-2023 "Determination of thermal conductivity and thermal diffusivity of plastics".

[0044] The mechanical properties were tested according to the standard GB / T1040.1-2018 "Determination of Tensile Properties of Plastics" to determine the tensile strength of the aging-resistant, thermally conductive, and flame-retardant polyurethane composite material.

[0045] The flame retardant properties were tested according to the standards GB / T 2406.2-2009 "Determination of Burning Behavior of Plastics by Oxygen Index Method" and GB / T2408-2021 "Determination of Burning Performance of Plastics by Horizontal and Vertical Methods" to determine the limiting oxygen index and vertical burning rating of the aging-resistant, thermally conductive, and flame-retardant polyurethane composite material.

[0046] Table 1 Table 2 As shown in the examples, the thermal conductivity of the polyurethane composite material before aging is 0.84-1.22 W / mK, the limiting oxygen index is 29-35%, the vertical flammability rating is V-0 to V-1, and the tensile strength is 65-78 MPa. After aging, the thermal conductivity of the polyurethane composite material is 0.80-1.12 W / mK, the limiting oxygen index is 24-32%, the vertical flammability rating is V0 to V-1, and the tensile strength is 61-72 MPa. It can be seen that the thermal conductivity, flame retardancy, and mechanical properties of the polyurethane composite material do not decrease significantly before and after aging, and it has good stability. This demonstrates that the polyurethane composite material of the present invention has excellent aging resistance and can maintain its thermal conductivity, flame retardancy, and mechanical properties stable for a long time.

[0047] As can be seen from Examples 1-3, as the polymerization reaction temperature for preparing fluorinated polyurethane increases, the thermal conductivity, limiting oxygen index, and tensile strength of the unaged polyurethane composite material first increase and then decrease. This is because as the reaction temperature increases, the polymerization reaction is promoted to be complete, which can effectively improve the overall performance of polyurethane. However, if the temperature is too high, the side reactions in the system increase, causing the polyurethane molecular chain structure to become differentiated, resulting in a decrease in performance.

[0048] As can be seen from Examples 2 and 4-5, the method of the present invention can use a variety of polyols to prepare fluorinated polyurethane matrices.

[0049] In Examples 6, 2, and 7, as the polymerization time of the fluorinated polyurethane increased, the thermal conductivity, limiting oxygen index, and tensile strength of the unaged polyurethane composite material first increased and then decreased. This is because as the reaction time increases, the polymerization reaction is promoted to be complete, which can effectively improve the performance of polyurethane. However, as the reaction time is prolonged, the side reactions in the system increase, which will damage the polyurethane structure and cause a decrease in performance.

[0050] With the total amount of modified titanium dioxide, antioxidant, and light stabilizer remaining constant, in Examples 9, 8, and 2, as the amount of modified titanium dioxide and light stabilizer gradually increases and the amount of antioxidant decreases, the thermal conductivity, limiting oxygen index, and tensile strength of the unaged polyurethane composite material gradually increase. Preferably, the mass ratio of the aminated tetra-arm polyethylene glycol modified titanium dioxide, antioxidant, and light stabilizer is 1:(1-5):(1-6). The polyurethane composite material has high thermal conductivity, limiting oxygen index, and tensile strength, as well as good aging resistance.

[0051] During the preparation of modified titanium dioxide, as the mass of aminated tetra-arm polyethylene glycol in Examples 10, 2 and 11 increased, the thermal conductivity, limiting oxygen index and tensile strength of the unaged polyurethane composite material first increased and then decreased. This is because increasing the amount of aminated tetra-arm polyethylene glycol can further improve the dispersion of modified titanium dioxide and the bonding effect between it and the fluorinated polyurethane interface, thereby improving the material's performance. However, further increasing the amount can, to some extent, cause slight defects in the polyurethane structure and dilution of its function, resulting in a slight deterioration in the material's performance.

[0052] During the preparation of modified titanium dioxide, as the modification reaction temperature increased in Examples 12, 2, and 13, the thermal conductivity, limiting oxygen index, and tensile strength of the unaged polyurethane composite material first increased and then decreased. This is because the increase in reaction temperature promotes the activity of titanium dioxide graft modification and improves its dispersion performance in the fluorinated polyurethane matrix. When the reaction temperature increases to a certain level, the reaction activity reaches its optimal level, and the aminated four-arm polyethylene glycol modifier can be uniformly grafted onto the surface of titanium dioxide, promoting the formation of a strong interfacial bond between the modified titanium dioxide and the fluorinated polyurethane matrix. If the temperature continues to rise, especially exceeding the activation energy of surface graft modification, it will cause excessive reaction or side reaction, such as thermal degradation or desorption of the aminated four-arm polyethylene glycol chain, which will cause the polar sites on the surface of titanium dioxide to be re-exposed, generating pyrolysis impurities (such as small molecule fragments), destroying the interfacial compatibility with the fluorinated polyurethane, and leading to a decrease in the performance of the material.

[0053] In the preparation of modified titanium dioxide, as the reaction time increased in Examples 14, 2, and 15, the thermal conductivity, limiting oxygen index, and tensile strength of the unaged polyurethane composite material first increased and then decreased. This is because, with increasing reaction time, the hydroxyl groups on the titanium dioxide surface react fully with the aminated tetra-arm polyethylene glycol, increasing the grafting rate and improving its interfacial compatibility with fluorinated polyurethane, thus enhancing performance. Further increasing the temperature leads to excessive side reactions and a decrease in performance.

[0054] As can be seen from Examples 2 and 16-17, the polyurethane composite material system of the present invention can use a variety of types of thermal conductive agents.

[0055] As can be seen from Examples 2 and 18-19, changing the mass ratio of ammonium polyphosphate, melamine cyanurate, and zinc borate has a slight effect on the thermal conductivity, flame retardant properties, and mechanical properties of polyurethane composites. The preferred mass ratio of the three is 1:(1-5):(1-2).

[0056] As can be seen from Examples 2 and Comparative Examples 1-3, the present invention, by modifying titanium dioxide and polyurethane matrix, improves the thermal conductivity, flame retardancy and tensile strength of polyurethane composite materials. The modified titanium dioxide and fluorinated polyurethane can interact to enhance the aging resistance of polyurethane composite materials in humid and hot environments and maintain the continuous stability of the thermal conductivity, flame retardancy and mechanical properties of polyurethane composite materials for cable joints.

[0057] The modified titanium dioxide is an aminated four-arm polyethylene glycol surface modification. Its surface hydroxyl and amino groups form a cross-linked entangled network structure with the polyurethane matrix, which enables the thermal conductive agent and flame retardant to be uniformly dispersed in the polyurethane matrix, thereby improving its thermal conductivity, flame retardant performance, and tensile strength. The modified titanium dioxide, together with antioxidants and light stabilizers, forms a composite anti-aging agent, forming a multi-stage synergistic effect of "prevention-inhibition-removal", which significantly improves the aging resistance of the polyurethane composite material. Fluorinated polyurethane provides high high-temperature thermal stability and forms a three-dimensional cross-linked network, which limits the loss of anti-aging agent, thermal conductive agent, and flame retardant under high temperature and humidity, and avoids performance loss caused by additive agglomeration. This invention improves the thermal conductivity, limiting oxygen index, vertical flammability rating, and tensile strength of the polyurethane composite material for cable joints after aging from multiple aspects, and maintains the stability of the thermal conductivity, flame retardant performance, and mechanical properties of the polyurethane composite material.

[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit the scope of protection of the present invention. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. A polyurethane composite material, characterized in that, The product comprises the following components in parts by weight: 75-100 parts of fluorinated polyurethane, 3-15 parts of anti-aging agent, 5-15 parts of thermal conductive agent, and 5-20 parts of flame retardant. The anti-aging agent comprises the following components in parts by weight: 0.1-3 parts of aminated tetra-arm polyethylene glycol-modified titanium dioxide, 0.1-5 parts of antioxidant, and 0.1-10 parts of light stabilizer. The fluorinated polyurethane is polymerized from isocyanate, fluorinated polyol, and amine chain extender.

2. The polyurethane composite material as described in claim 1, characterized in that, The mass ratio of the aminated four-arm polyethylene glycol modified titanium dioxide, antioxidant and light stabilizer is 1:(1-5):(1-6).

3. The polyurethane composite material as described in claim 1, characterized in that, Includes at least one of the following: The isocyanate includes at least one of alicyclic isocyanates, phenyl isocyanates, and alkyl isocyanates; The fluorinated polyol includes at least one of perfluoropolyether diol, fluorinated polyepoxybutane polyol or perfluorodecanediol; The amine chain extender includes at least one of diethylenetriamine, 3,5-diethyltoluenediamine, polyoxypropylenetriamine, and isophoronediamine.

4. The polyurethane composite material as described in claim 1, characterized in that, The mass ratio of the isocyanate, fluorinated polyol and amine chain extender is (5-15):(1-5):

1.

5. The polyurethane composite material as described in claim 1, characterized in that, The thermal conductive agent includes at least one of aluminum oxide, boron nitride, or aluminum nitride.

6. The polyurethane composite material as described in claim 1, characterized in that, Includes at least one of the following: The flame retardant includes at least one of ammonium polyphosphate, melamine cyanurate, or zinc borate; The antioxidants include at least one of hindered phenolic antioxidants and phosphite antioxidants; The light stabilizer includes hindered amine light stabilizers.

7. The polyurethane composite material as described in claim 6, characterized in that, The flame retardant includes ammonium polyphosphate, melamine cyanurate and zinc borate, wherein the mass ratio of ammonium polyphosphate, melamine cyanurate and zinc borate is 1:(1-5):(1-2).

8. A method for preparing the polyurethane composite material according to any one of claims 1-7, characterized in that, Includes the following steps: S1. In an organic solvent, isocyanate, fluorinated polyol and amine chain extender undergo a polymerization reaction to obtain the fluorinated polyurethane; S2. In an organic solvent, titanium dioxide and aminated tetra-armed polyethylene glycol undergo a surface modification reaction, followed by washing and drying to obtain the aminated tetra-armed polyethylene glycol-modified titanium dioxide. S3. Mix the aminated tetra-armed polyethylene glycol-modified titanium dioxide, antioxidant, and light stabilizer to obtain the anti-aging agent; S4. Mix the fluorinated polyurethane, the anti-aging agent, the flame retardant, and the thermal conductive agent evenly to obtain the polyurethane composite material.

9. The method for preparing the polyurethane composite material according to claim 1, characterized in that, Includes at least one of the following: In step S1, the mass ratio of the isocyanate, fluorinated polyol and amine chain extender is (5-15):(1-5):1; In step S1, the organic solvent includes N,N-dimethylformamide; In step S1, the polymerization reaction temperature is 60-75℃, and the polymerization reaction time is 4-8 hours. In step S1, the mass concentration of the amine chain extender in the organic solvent is 50-100 g / L; In step S2, the mass ratio of titanium dioxide to aminated tetraarm polyethylene glycol is 1:(0.5-2); In step S2, the surface modification reaction temperature is 80-100℃, and the surface modification reaction time is 6-10h.

10. A cable, characterized in that, Including the polyurethane composite material according to any one of claims 1-7.

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