A polyurethane material, a process for its preparation and a cable joint article comprising it

Abstract

The application belongs to the field of cable materials, and specifically discloses a polyurethane material, a preparation method thereof and a cable joint product containing the polyurethane material. The polyurethane material is prepared through an AB component, adopts flaky and spherical alumina as fillers, and is cooperated with an interface modifier, a plasticizer, a defoaming agent and other components of a system, so that the material can obviously improve the heat conduction performance and fluidity of the material on the basis of maintaining good insulation performance, is more suitable for being applied to filling and sealing materials of a cable joint, and achieves the purpose of improving the long-term stability and safety performance of the cable joint product.

Description

Technical Field

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

[0002] As a critical hub for energy transmission, the long-term operational reliability of cables directly depends on the comprehensive thermal-electrical-mechanical performance of their internal filling materials. With the continuous increase in grid voltage levels and load density, the temperature rise problem caused by the Joule heating effect of conductors is becoming increasingly prominent, and existing encapsulation systems, represented by silicone rubber or epoxy resin, have several limitations. For example, the inherent low thermal conductivity of silicone rubber matrix leads to continuous heat accumulation inside the joint, forming a vicious thermal cycle and accelerating the aging and failure of the insulation medium; while epoxy resin has advantages in mechanical strength, under the high filler content required to achieve effective thermal conductivity, the material exhibits significant shear-thinning characteristics and non-Newtonian fluid behavior, making it difficult to complete defect-free injection of complex multi-scale cavities within a limited construction window.

[0003] Compared to silicone rubber and epoxy resin, polyurethane molecular chains are flexible and rich in polar groups. This allows for the formation of continuous phonon channels through hydrogen bonding and microphase separation structures at low filler contents, achieving a balance between high thermal conductivity and low viscosity, enabling rapid heat dissipation and preventing localized overheating. Simultaneously, its low-polarity soft-hard segment synergistic network imparts higher intrinsic volume resistivity and lower dielectric loss, making it more suitable as a filler material matrix for cable joint components. However, a deeper structural contradiction in practical applications lies in the fact that when attempting to improve performance by directly adding thermally conductive fillers, the interfacial energy mismatch between the inorganic phase and the polyurethane organic matrix, along with the disordered topology of the dispersed phase, not only causes abnormal wide-range dielectric spectrum response but also induces electric field distortion, leading to irreversible attenuation of insulation strength. This triangular dilemma of thermal management failure, processability deterioration, and dielectric performance degradation means that traditional material systems can no longer meet the requirements of the new generation of high-voltage power equipment for filling media that are "high thermal conductivity, good insulation, high filling capacity, and good flowability." There is an urgent need to upgrade the structure through material compounding design and interface engineering so that such filling materials can simultaneously possess high thermal conductivity, good insulation, and flowability. Summary of the Invention

[0004] In view of the problems that the existing polyurethane filler materials for cables cannot simultaneously achieve thermal conductivity, insulation and flowability, the present invention will provide a polyurethane material, a method for preparing the same, and a cable joint component containing the same.

[0005] To achieve the above objectives, the following technical solutions are specifically included: In a first aspect, the present invention provides a polyurethane material, which is prepared from component A and component B, wherein component A comprises the following raw material components in parts by weight: 50-100 parts of polyisocyanate, 10-20 parts of chain extender, 10-20 parts of plasticizer, 5-20 parts of spherical alumina, and 5-20 parts of flake alumina. Component B comprises the following raw material components in parts by weight: 30-40 parts of polyether polyol, 0.5-2 parts of interface modifier, 0.1-1 parts of defoamer, 0.1-2 parts of antioxidant, and 0.1-1 parts of catalyst.

[0006] The polyurethane material of this invention is obtained by reacting components A and B; and the polyurethane material includes two fillers with different morphologies: spherical alumina and lamellar alumina. The lamellar alumina forms a highly tortuous tunneling barrier along the electric field direction, effectively extending the electron migration path; the spherical alumina fills the interlayer micropores, reducing the free volume fraction of the system; the two form a multi-scale topological structure in the polyurethane matrix, constructing a spatially misaligned and segmented coupled insulating framework; at the same time, the polyurethane matrix itself has a low density of polar groups and a small dipole moment, which endows it with high intrinsic volume resistivity and low dielectric loss, providing a basic insulating barrier for the composite system.

[0007] An interface modifier introduces a nanoscale coupling layer on the surfaces of two alumina morphologies, enabling chemical bonding between the polyurethane and the alumina interfaces. This chemical bonding further suppresses polarization relaxation, ensuring stable overall insulation performance across a wide temperature range. Furthermore, the nanoscale coupling layer on the alumina surfaces can, on the one hand, block direct electron transitions at the inorganic-organic interface, and on the other hand, form deep-level traps to capture high-energy carriers, suppressing space charge accumulation and electric field distortion, thereby significantly improving the material's resistance to electrical tree aging.

[0008] Lamellar alumina constructs a highly oriented two-dimensional framework along the heat flow direction, providing low-scattering channels for phonons. Spherical alumina fills the gaps between the lamellar layers, forming point-to-surface composite contacts, reducing the thermal resistance at the lamellar interface and inhibiting agglomeration, thereby significantly expanding the effective thermal conductivity cross-sectional area. After modifying the two morphologies of alumina with an interface modifier, the surface coupling layer passivates the hydroxyl groups on the alumina surface, enhancing the phonon coupling at the alumina-polyurethane interface. This enables efficient heat transfer along the three-dimensional percolation network of "lamella-sphere-matrix," achieving synergistic thermal conduction on a macroscopic scale, resulting in a significant increase in the material's thermal conductivity. Furthermore, this network allows for rapid heat diffusion and temperature gradient homogenization, inhibiting the formation of local hot spots, mitigating chain relaxation induced by thermal stress cycles, and delaying the thermo-oxidative aging process of polyurethane, which is beneficial for the long-term stable operation of polyurethane-filled materials in practical applications.

[0009] This invention synergistically weakens polyurethane prepolymer chain entanglement by introducing plasticizers and defoamers into the polyurethane matrix, creating a low-viscosity shear-thinning fluid and endowing the material with excellent self-leveling properties. The defoamer spreads rapidly at the gas-liquid interface, reducing the surface tension gradient and promoting microbubble coalescence and rupture. The system exhibits low viscosity and stability at room temperature, enabling defect-free single-pass filling of complex cavities. The curing process results in low shrinkage and low internal stress, ensuring long-term sealing reliability when the polyurethane material is used as a cable connector filler.

[0010] Therefore, the polyurethane material of the present invention can simultaneously possess good insulation, thermal conductivity, and flowability.

[0011] Preferably, the mass ratio of component A to component B is (3-6):1, which can be 3:1, 3.5:1, 4:1, 4.5:1, 5:1, 5.5:1, 6:1, or any value between the two mentioned above.

[0012] Preferably, the average particle size of the spherical alumina is 0.3μm-30μm, specifically it can be 0.3μm, 1μm, 2μm, 3μm, 4μm, 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, or a range between any two of the above values.

[0013] Preferably, the average particle size of the flake-shaped alumina is 5μm-30μm; specifically, it can be 5μm, 6μm, 7μm, 8μm, 9μm, 10μm, 11μm, 12μm, 13μm, 14μm, 15μm, 16μm, 17μm, 18μm, 19μm, 20μm, 21μm, 22μm, 23μm, 24μm, 25μm, 26μm, 27μm, 28μm, 29μm, 30μm, or a range between any two of the above values.

[0014] Preferably, based on the total mass of components A and B, the mass percentage of the spherical alumina is 15%-35%; specifically, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or a range between any two of the above values.

[0015] Preferably, the total mass of component A and component B, and the mass percentage of the flake alumina, is 15%-35%; specifically, it can be 15%, 16%, 17%, 18%, 19%, 20%, 21%, 22%, 23%, 24%, 25%, 26%, 27%, 28%, 29%, 30%, 31%, 32%, 33%, 34%, 35%, or a range between any two of the above values.

[0016] Preferably, in component B, the interface modifier includes at least one of epoxy silane coupling agents, amino-modified silane coupling agents, and titanate coupling agents.

[0017] More preferably, the epoxy silane coupling agent comprises γ-glycidoxypropyltrimethoxysilane (KH-560).

[0018] More preferably, the amino-modified silane coupling agent includes at least one of γ-aminopropyltriethoxysilane (KH-550) and N-β-aminoethyl-γ-aminopropyltrimethoxysilane (KH-792).

[0019] More preferably, the titanate coupling agent comprises isopropyl tris(dioctylpyrophosphoryloxy) titanate (NDZ-201).

[0020] Preferably, in component A, the polyisocyanate includes at least one of aromatic polyisocyanate and alicyclic polyisocyanate.

[0021] More preferably, the aromatic polyisocyanate includes at least one of toluene diisocyanate, diphenylmethane diisocyanate, polymethylene polyphenyl polyisocyanate, and tetramethylphenylmethylene diisocyanate.

[0022] More preferably, the aliphatic polyisocyanate includes at least one of hexamethylene diisocyanate, isophorone diisocyanate, and dicyclohexylmethane diisocyanate.

[0023] Preferably, in component A, the chain extender includes at least one of hexamethylenediamine, 1,4-butanediamine, isophoronediamine, and m-phenylenediamine.

[0024] Preferably, in component A, the plasticizer includes at least one of epoxidized soybean oil, dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and dioctyl sebacate.

[0025] Preferably, in component B, the polyether polyol includes at least one of polytetrahydrofuran ether polyol, polypropylene glycol, and polyglycerol.

[0026] More preferably, the molecular weight of the polypropylene glycol is 1000-2000.

[0027] More preferably, the molecular weight of the polyglycerol is 1000-3000.

[0028] Preferably, in component B, the defoamer includes at least one of methyl silicone oil, polyether-modified silicone oil, and modified acetylenic diol.

[0029] Preferably, in component B, the antioxidant includes at least one of pentaerythritol ester, octadecyl alcohol ester of β-propionate, triphosphite, dipentaerythritol diphosphite, macromolecular phosphite, and dodecyl thiodipropionate.

[0030] Preferably, in component B, the catalyst comprises at least one of bis(dimethylaminoethyl) ether, stannous octanoate, dibutyltin diacetate, triethylenediamine, and dibutyltin dilaurate.

[0031] Secondly, the present invention provides a method for preparing the polyurethane material, comprising the following steps: S1. Mix polyisocyanate, chain extender, plasticizer, spherical alumina and flake alumina evenly to obtain component A; S2. Mix the polyether polyol, interface modifier, defoamer, antioxidant and catalyst evenly to obtain component B; S3. Mix, degas and cure components A and B sequentially to obtain polyurethane material.

[0032] Preferably, in step S3, the mixing is carried out under stirring, the stirring speed of the plastic is 100-300 rpm, and the stirring time is 15-60 min.

[0033] Preferably, in step S3, the degassing is performed by vacuuming to -0.07MPa to -0.1MPa to remove bubbles.

[0034] Preferably, in step S3, the curing time is 12-24 hours.

[0035] Thirdly, the present invention provides a cable connector component, including a filler material, wherein the filler material includes the aforementioned polyurethane material.

[0036] Compared with the prior art, the present invention has the following beneficial effects: The polyurethane material of the present invention is prepared by AB components, which uses alumina with two morphologies, namely flake and spherical, as filler. At the same time, the interface modifier, plasticizer and defoamer of the system can significantly improve the thermal conductivity and fluidity of the material while maintaining good insulation performance, making it more suitable for use as a filling and sealing material for cable joints, so as to improve the long-term stability and safety performance of cable joint components. Attached Figure Description

[0037] Figure 1 These are scanning electron microscope (SEM) images of cross-sections of polyurethane-based filler materials for cable joints in Comparative Examples 1, 3, and 1 of this invention. Detailed Implementation

[0038] 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.

[0039] Partial raw material information: 0.3μm spherical Al2O3: average particle size 0.3μm, Dongchao New Materials Technology Co., Ltd., DCA-0.3S; 5μm spherical Al2O3: average particle size 5μm, Dongchao New Materials Technology Co., Ltd., DCA-5S; 10μm spherical Al2O3: average particle size 10μm, Dongchao New Materials Technology Co., Ltd., DCA-10S; 20μm spherical Al2O3: average particle size 20μm, Dongchao New Materials Technology Co., Ltd., DCA-20S; 30μm spherical Al2O3: average particle size 30μm, Dongchao New Materials Technology Co., Ltd., DCA-30S; 10μm spherical Al2O3: average particle size 10μm, Dongchao New Materials Technology Co., Ltd., DCF-4000T; 10μm sheet-like Al2O3: average particle size 10μm, Jinge New Materials Co., Ltd., GD-S102ANS; 20μm sheet-like Al2O3: average particle size 20μm, Jinge New Materials Co., Ltd., GD-S33ANS; 10μm sheet-like boron nitride: average particle size 10μm, Baitu High-Tech Materials Co., Ltd., PBN-10; Methyl silicone oil: Qiangli Chemical Co., Ltd., QL-200 DM5; Polyether-modified silicone oil: Huahao Chemical Co., Ltd., HH-2032; Modified acetylenic diol: Canghong Industrial Co., Ltd., BETTERSOL 440.

[0040] Example 1 S1: According to the weight of raw materials, 60 parts of toluene diisocyanate, 15 parts of hexamethylenediamine, 15 parts of epoxidized soybean oil, 10 parts of 10μm spherical alumina and 20 parts of 10μm flake alumina are heated and stirred in a closed container to initially react and obtain component A; the heating temperature is 100℃, the stirring speed is 300rpm, and the stirring time is 2h. S2: According to the weight, add 1 part KH-550, 0.5 parts methyl silicone oil, 0.5 parts pentaerythritol ester and 0.5 parts stannous octoate to 35 parts polypropylene glycol 1000. Stir at low speed in a closed container at room temperature to disperse the components evenly to obtain component B; the stirring temperature is 25℃, the stirring speed is 150 rpm, and the stirring time is 1 hour. S3: Mix components A and B in a mass ratio of 4:1, stir at 200 rpm for 0.5 h at room temperature, and remove air bubbles by vacuuming to -0.07 MPa to obtain a premix; fill the premix into the cable joint, and finally cure at room temperature for 18 h to obtain a cable joint component filled with polyurethane material.

[0041] Examples 2-5 Compared with Example 1, the amounts of spherical alumina and flake alumina were changed, as detailed in Table 1, while the rest remained the same.

[0042] Examples 6-9 Compared with Example 1, the particle size of the spherical alumina was changed, as detailed in Table 1, while the rest remained the same.

[0043] Examples 10-11 Compared with Example 1, the particle size of the flake alumina was changed, as detailed in Table 1, while the rest remained the same.

[0044] Examples 12-15 Compared with Example 1, the type and / or amount of defoamer were changed, as detailed in Table 1, while the rest remained the same.

[0045] Examples 16-17 Compared with Example 1, the amount of each raw material component was changed, as detailed in Table 2, while the rest remained the same.

[0046] Comparative Example 1 Compared with Example 1, it contains 30 parts by weight of spherical alumina and no flaky alumina, as detailed in Table 2, with the rest being the same.

[0047] Comparative Example 2 Compared with Example 1, it contains 30 parts by weight of flake alumina and no spherical alumina, as detailed in Table 2, with the rest being the same.

[0048] Comparative Example 3 Compared with Example 1, there are no spherical alumina and flake alumina, as detailed in Table 2, otherwise the same.

[0049] Comparative Example 4 Compared to Example 1, this example does not contain methyl silicone oil, as detailed in Table 2; otherwise, they are the same.

[0050] Comparative Example 5 Compared with Example 1, KH-550 is not included, as detailed in Table 2, otherwise the same.

[0051] Comparative Example 6 Compared with Example 1, spherical silica was used to replace spherical alumina in equal amounts, as detailed in Table 2, while the rest remained the same.

[0052] Comparative Example 7 Compared with Example 1, sheet boron nitride was used to replace sheet alumina in equal amounts, as detailed in Table 2, while the rest remained the same.

[0053] Table 1 Table 2 Performance testing: (1) Viscosity: Refer to GB / T 2794-2022 standard, and use a digital viscometer to measure the viscosity of components A and B within half an hour after mixing. When the viscosity is <14000mPa·s, it is considered qualified.

[0054] (2) Thermal conductivity: Referring to GB / T42919.4-2023 standard, the thermal conductivity of the polyurethane-based filler material after curing was evaluated using a laser thermal conductivity meter. A thermal conductivity > 0.6 W / mK is considered qualified.

[0055] (3) Insulation performance: Referring to GB / T 1410-2006 standard, the volume resistivity of polyurethane-based filler material after curing was evaluated using a high insulation resistance measuring instrument. The higher the volume resistivity, the better the insulation performance.

[0056] (4) The surfaces of the polyurethane-based fillers in Example 1, Comparative Example 1, and Comparative Example 3 were observed using a scanning electron microscope. The test results are as follows: Figure 1 As shown, from Figure 1 As can be observed, the spherical and sheet-like alumina in Example 1 are uniformly dispersed and embedded in the polyurethane matrix, serving as a skeleton material in the polyurethane matrix, which is beneficial to improving the thermal conductivity of the material.

[0057] The test results for viscosity, thermal conductivity, and volume resistivity are shown in Table 3.

[0058] Table 3 The performance test results in Table 3 show that the addition of micron-sized spherical Al2O3 and flake-shaped Al2O3 to the polyurethane-based filler material significantly increases the viscosity and improves the thermal conductivity. The thermal diffusivity and thermal conductivity of the filler material are positively correlated with the amount added. The polyurethane filler material of this invention has a viscosity of less than 14000 mPa·s, a thermal conductivity greater than 0.6 W / mK, and a resistivity greater than 4.9 × 10⁻⁶. 12 It is evident that it possesses both high thermal conductivity and insulation properties as well as good fluidity.

[0059] According to Example 1 and Comparative Examples 1 and 2, the present invention demonstrates a significant synergistic enhancement effect in improving the thermal conductivity of materials through the combined use of spherical alumina and lamellar alumina. In Example 1, using a ratio of 10 parts spherical alumina to 20 parts lamellar alumina, the thermal conductivity of the polyurethane material reached 0.78 W / mK; in contrast, the thermal conductivity of Comparative Example 1 (with only 30 parts spherical alumina) and Comparative Example 2 (with only 30 parts lamellar alumina) were 0.58 W / mK and 0.56 W / mK, respectively. This result confirms that lamellar alumina can construct a two-dimensional thermally conductive framework in the matrix, while spherical alumina effectively fills the gaps between the lamellars, forming a "point-to-surface composite" thermally conductive percolation network, thereby significantly improving the overall thermal conductivity efficiency of the system. Furthermore, the viscosity of Example 1 is approximately 12,500 mPa·s, which is below the processable threshold of 14,000 mPa·s, indicating that at this compounding ratio, the material maintains good flowability and processability while achieving a significant improvement in thermal conductivity.

[0060] Based on the performance comparison between Comparative Example 3 (without thermally conductive filler) and Example 1 (with 20 wt% spherical-sheet composite alumina), the thermal conductivity of the polyurethane material of this invention significantly increased from 0.32 W / mK to 0.78 W / mK after the introduction of composite alumina, an increase of approximately 144%. Simultaneously, the volume resistivity of the material increased from 3.65 × 10¹² Ω·cm to 6.89 × 10¹² Ω·cm. These results indicate that, under the formulation of the examples, the addition of alumina filler not only did not impair the insulation performance of the material, but also enhanced the interfacial bonding between the filler and the polyurethane matrix through the action of an interface modifier, effectively suppressing interfacial polarization and carrier migration. Thus, while significantly improving thermal conductivity, the insulation properties of the system were maintained and improved.

[0061] Comparing the test results of Comparative Example 4 (without defoamer) and Example 1 (with 0.5 parts of methyl silicone oil defoamer), it can be seen that the absence of defoamer caused the system viscosity to increase to 18500 mPa·s and the volume resistivity to decrease to 1.89 × 10¹² Ω·cm. This indicates that without defoamer, the residual bubbles in the system not only cause a significant increase in viscosity and affect the material flow and filling effect, but also form microscopic air gaps at the solid-liquid interface, disrupting the insulation continuity and thus reducing the insulation reliability of the material. In contrast, Example 1, by introducing 0.5 parts of methyl silicone oil defoamer, effectively controlled the viscosity at 12500 mPa·s and maintained the volume resistivity at 6.89 × 10¹² Ω·cm, demonstrating that defoamer can significantly improve the rheological behavior of the system, promote bubble removal, reduce interface defects, and play a key role in maintaining the material's flowability during construction and its insulation integrity after curing.

[0062] A comparison of performance data between Comparative Example 5 (without interface modifier) ​​and Example 2 (with KH-550 interface modifier) ​​shows that the interface modifier plays a crucial role in improving both the insulation and thermal conductivity of this system. Without the interface modifier, the volume resistivity of the resulting material is 7.31 × 10¹¹ Ω·cm, significantly lower than the 5.41 × 10¹² Ω·cm of Example 2. This result indicates that the interface modifier can form a chemical coupling layer on the surface of the alumina filler, enhancing its interfacial bonding with the polyurethane matrix through covalent bridging, thereby effectively suppressing charge accumulation and local electric field distortion at the interface, and significantly improving the insulation reliability of the composite material. Simultaneously, the thermal conductivity of Comparative Example 5 is 0.67 W / mK, lower than the 0.73 W / mK of Example 2. This is attributed to the interface modifier further optimizing the heat conduction path and improving the thermal conductivity efficiency of the system by reducing phonon scattering and interfacial thermal resistance between the filler and the matrix. Therefore, the interface modifier in this invention has the dual function of enhancing interfacial insulation integrity and promoting the construction of a thermally conductive network.

[0063] The performance comparison results of Comparative Example 6 (using spherical silica), Comparative Example 7 (using sheet-like boron nitride), and Examples 1-3 (using spherical-sheet composite alumina) show that different filler systems have a significant impact on the thermal conductivity of the composite material. The thermal conductivity of the silica and boron nitride systems is 0.54 W / mK and 0.59 W / mK, respectively, both significantly lower than the 0.73-0.78 W / mK of the composite alumina system. This difference can be attributed to the superior performance matching of the alumina filler in this system: it possesses higher intrinsic thermal conductivity, and its phonon vibration spectrum is closer to that of the polyurethane matrix, which is beneficial for reducing interfacial phonon scattering. Simultaneously, the combination of spherical and sheet-like morphologies allows for the construction of a three-dimensional thermally conductive network within the matrix, significantly improving thermal conductivity. Furthermore, after modification with an interface modifier, a stable chemical coupling layer is formed on the alumina surface, which not only enhances the interfacial bonding between the filler and the resin and reduces interfacial thermal resistance but also effectively maintains the high insulation performance of the system. Therefore, compared with silicon dioxide and boron nitride, the sphere-plate composite alumina used in this invention achieves high thermal conductivity while also having good insulation compatibility and process feasibility, demonstrating a better overall performance balance.

[0064] 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 material, characterized in that, It is prepared from component A and component B. Component A includes the following raw material components in parts by weight: 50-100 parts of polyisocyanate, 10-20 parts of chain extender, 10-20 parts of plasticizer, 5-20 parts of spherical alumina, and 5-20 parts of flake alumina. Component B comprises the following raw material components in parts by weight: 30-40 parts of polyether polyol, 0.5-2 parts of interface modifier, 0.1-1 parts of defoamer, 0.1-2 parts of antioxidant, and 0.1-1 parts of catalyst.

2. The polyurethane material as described in claim 1, characterized in that, The average particle size of the spherical alumina is 0.3 μm-30 μm.

3. The polyurethane material as described in claim 1, characterized in that, The average particle size of the flaky alumina is 5μm-30μm.

4. The polyurethane material as described in claim 1, characterized in that, Based on the total mass of components A and B, the mass percentage of the spherical alumina is 15%-35%.

5. The polyurethane material as described in claim 1, characterized in that, Based on the total mass of components A and B, the mass percentage of the sheet-like alumina is 15%-35%.

6. The polyurethane material as described in claim 1, characterized in that, In component B, the interface modifier includes at least one of epoxy silane coupling agents, amino-modified silane coupling agents, and titanate coupling agents.

7. The polyurethane material as described in claim 1, characterized in that, Includes at least one of the following: In component A, the polyisocyanate includes at least one of aromatic polyisocyanate and alicyclic polyisocyanate; In component A, the chain extender includes at least one of hexamethylenediamine, 1,4-butanediamine, isophoronediamine, and m-phenylenediamine; In component A, the plasticizer includes at least one of epoxidized soybean oil, dioctyl phthalate, dibutyl phthalate, dioctyl adipate, and dioctyl sebacate.

8. The polyurethane material as described in claim 1, characterized in that, Includes at least one of the following: In component B, the polyether polyol includes at least one of polytetrahydrofuran ether polyol, polypropylene glycol, and polyglycerol; In component B, the defoamer includes at least one of methyl silicone oil, polyether-modified silicone oil, and modified acetylenol. In component B, the antioxidant includes at least one of pentaerythritol ester, octadecyl alcohol ester of β-propionate, triphosphite, dipentaerythritol diphosphite, macromolecular phosphite, and dodecyl thiodipropionate. In component B, the catalyst includes at least one of bis(dimethylaminoethyl) ether, stannous octanoate, dibutyltin diacetate, triethylenediamine, and dibutyltin dilaurate; The mass ratio of component A to component B is (3-6):

1.

9. A method for preparing the polyurethane material according to any one of claims 1-8, characterized in that, Includes the following steps: S1. Mix polyisocyanate, chain extender, plasticizer, spherical alumina and flake alumina evenly to obtain component A; S2. Mix the polyether polyol, interface modifier, defoamer, antioxidant and catalyst evenly to obtain component B; S3. Mix, degas and cure components A and B sequentially to obtain polyurethane material.

10. A cable connector component, characterized in that, It includes a filler material, said filler material including the polyurethane material according to any one of claims 1-8.

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