Polyurethane filling adhesive as well as preparation method and application thereof

Abstract

The invention discloses a polyurethane filling adhesive as well as a preparation method and application thereof, and relates to the field of cable materials. The polyurethane filling adhesive comprises hydrophobic polyurethane, an anti-hydrolysis agent, a heat conducting agent and a flame retardant; the hydrophobic polyurethane is formed by polymerizing a soft segment, a hard segment and an amine chain extender, and the soft segment comprises at least one of polytetrahydrofuran ether, dihydroxybutyl-terminated polydimethylsiloxane and aminopropyl terminated polydimethylsiloxane; the anti-hydrolysis agent comprises triisopropanolamine, a carbodiimide anti-hydrolysis agent and an epoxy silane anti-hydrolysis agent. Hydrophobic polyurethane adopts a soft segment containing hydrophobic groups, hydrolysis is inhibited from the source, meanwhile, the hydrolysis resistance is improved in cooperation with the ternary compound hydrolysis-resistant agent, a compact highly-physical cross-linked network is constructed, hydrolysis is inhibited from a chemical structure and a physical barrier community through cooperation of the three components, and long-acting hydrolysis-resistant protection is achieved; and the stability of heat-conducting property and flame-retardant property of the material is maintained in a severe environment in which a high-voltage cable is used.

Description

Technical Field

[0001] This invention relates to the field of cable materials technology, and in particular to a polyurethane filler adhesive, its preparation method, and its application. Background Technology

[0002] Polyurethane fillers are widely used in high-voltage cables due to their excellent adhesion, elasticity, and processability. They require excellent sealing properties to isolate moisture and prevent electrochemical corrosion within the cable; simultaneously, they must ensure timely heat dissipation during cable operation to avoid major accidents caused by localized overheating and fires. However, susceptibility to hydrolysis remains a core bottleneck restricting their service life and reliability. Accompanying defects such as insufficient thermal conductivity and poor flame retardancy further exacerbate application risks. The hydrolysis problem stems from the ester bond structure in the polyurethane molecular chain. In humid environments, aqueous media, or under alternating hot and humid conditions, these ester bonds are easily attacked and broken by water molecules, leading to molecular chain degradation. This process causes a precipitous decline in the material's mechanical and adhesive properties, resulting in cracking and powdering, directly causing cable sealing failure and shortening equipment lifespan.

[0003] Currently, traditional polyurethane fillers used in high-voltage cables have several shortcomings. For example, high-voltage cables are often laid underground, in tunnels, and other humid environments, and may even be submerged in water for extended periods. Traditional fillers have insufficient hydrolysis resistance; in a humid and hot environment of 85°C and 85%RH, the tensile strength retention drops to below 50% after only 300 hours, and in underwater immersion environments, significant cracking occurs within less than 200 hours. Secondly, cables generate a large amount of heat during high-load operation. Traditional fillers have low thermal conductivity (≤0.3 W / (m·K), leading to heat accumulation and excessively high local temperatures, thus shortening the cable's lifespan. Furthermore, high-voltage cables, as crucial power transmission carriers, have extremely high safety requirements. Traditional fillers have low flame retardancy ratings, with most products only reaching UL94 V-2 level. In the event of a fire, the released toxic fumes can cause serious harm to rescue efforts and the environment, failing to meet the safety regulations required in the high-voltage cable field.

[0004] To address the numerous problems existing in current polyurethane fillers, existing technologies often employ the addition of anti-hydrolysis agents to capture the carboxylic acids produced during the hydrolysis reaction and inhibit its continued progression. However, traditional anti-hydrolysis agents are themselves easily degraded by water, and their effectiveness in long-term humid or immersion environments typically does not exceed 500 hours, failing to provide long-term protection and increasing material costs. Therefore, there is an urgent need to develop a polyurethane filler that combines hydrolysis resistance, thermal conductivity, and flame retardancy in complex application environments, thereby driving advancements in cable technology and expanding its application areas. Summary of the Invention

[0005] This invention provides a polyurethane filler adhesive, its preparation method, and its application. Through the synergistic effect of hydrophobic modification of the polyurethane molecular structure and anti-hydrolysis agent, the permeation of water molecules is reduced, the hydrolysis resistance of the material is improved, and excellent and stable thermal conductivity and flame retardant properties can be maintained.

[0006] To solve the above-mentioned technical problems, one of the objectives of this invention is to provide a polyurethane filler adhesive, comprising the following components by weight: 60-100 parts hydrophobic polyurethane, 1-20 parts anti-hydrolysis agent, 1-8 parts thermal conductive agent, and 1-5 parts flame retardant. The hydrophobic polyurethane is polymerized from soft segments, hard segments and amine chain extenders, wherein the soft segments include at least one of polytetrahydrofuran ether, dihydroxybutyl polydimethylsiloxane, and aminopropyl-terminated polydimethylsiloxane. The anti-hydrolysis agent includes triisopropanolamine, carbodiimide anti-hydrolysis agent and epoxysilane anti-hydrolysis agent in a mass ratio of 1:(1-5):(1-4).

[0007] This application addresses the insufficient hydrolysis resistance of traditional polyurethane fillers. On one hand, it modifies the molecular structure of hydrophobic polyurethane by incorporating hydrophobic groups in the soft segments, effectively reducing water molecule adsorption and penetration, thus inhibiting hydrolysis at its source. On the other hand, it employs a ternary compound anti-hydrolysis agent to synergistically enhance the hydrolysis resistance of the hydrophobic polyurethane. Among these, the epoxy silane anti-hydrolysis system serves as a "physical barrier cornerstone." The epoxy groups in its molecules can undergo cross-linking reactions with the hydrophobic polyurethane molecular chains and the hydroxyl groups of triisopropanolamine, forming a stable siloxane (Si-O-Si) cross-linking network after hydrolysis. This constructs a dense, highly physically cross-linked network that can physically block water molecule penetration channels, reduce water molecule penetration rates and molecular chain hydrolysis sensitivity, while simultaneously improving system compatibility. This is the core guarantee for achieving "long-lasting hydrolysis resistance." The highly dense cross-linked network formed by triisopropanolamine and the isocyanate groups of hydrophobic polyurethane reduces water molecule intrusion channels, improves the capture efficiency of carbodiimide-based compounds for carboxylic acids generated by hydrolysis, avoids the problem of easy hydrolysis of carbodiimide alone, and extends the shelf life of the anti-hydrolysis agent. The three work synergistically to inhibit hydrolysis through a combination of chemical structure and physical barriers. Through the hydrophobic modification of the polyurethane molecular structure and the synergistic effect of the anti-hydrolysis agent, long-term hydrolysis resistance of polyurethane filler is achieved, enabling the polyurethane filler material to maintain excellent thermal conductivity and flame retardant properties in the harsh environment of high-voltage cable use.

[0008] In some embodiments, the hydrophobic polyurethane is polymerized from soft segments, hard segments, and an amine chain extender in a mass ratio of (1-5):(2-4):1.

[0009] In some embodiments, the hard segment includes at least one of isophorone diisocyanate, diphenylmethane diisocyanate, and toluene diisocyanate.

[0010] In some embodiments, the amine chain extender includes at least one of diethylenetriamine and 3,5-diethyltoluenediamine.

[0011] This application optimizes the mass ratio of soft segments, hard segments, and amine chain extenders in hydrophobic polyurethane within the above-mentioned range. At the same time, the soft segments are selected from hydrophobic polyethers / siloxanes, the hard segments are selected from highly stable isocyanates, and the chain extenders are selected from amines. A dense and flexible physical cross-linked network is constructed through polymerization reaction, which not only enhances hydrophobicity to prevent water penetration but also reduces the sensitivity of molecular chain hydrolysis, while ensuring the basic mechanical properties of the material.

[0012] In some embodiments, the thermal conductive agent includes at least one of aluminum oxide, boron nitride, and graphene.

[0013] In some embodiments, the thermal conductive agent comprises aluminum oxide, boron nitride, and graphene in a mass ratio of 1:(1-3):(1-2).

[0014] The thermal conductive agent in this application utilizes the synergistic effect of multidimensional alumina, boron nitride, and graphene to construct a continuous thermal conductive pathway. Compared with a single-component thermal conductive agent system, the use of a ternary composite thermal conductive agent can improve the hydrolysis resistance to a certain extent and maintain efficient thermal conductivity.

[0015] In some embodiments, the carbodiimide antihydrolysis agent includes at least one of bis(2,6-diisopropylphenyl)carbodiimide and N,N-dicyclohexylcarbodiimide.

[0016] In some embodiments, the epoxy silane anti-hydrolysis agent includes at least one of 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and epoxycyclohexylethyl-terminated polydimethylsiloxane.

[0017] In some embodiments, the flame retardant includes at least one of magnesium hydroxide, melamine cyanurate, and zinc borate.

[0018] This application uses a halogen-free system of magnesium hydroxide, melamine cyanurate, and zinc borate as the flame retardant. This system improves the flame retardant properties of the material while maintaining low addition levels, and solves the performance conflict problem caused by traditional high-addition functional fillers without affecting hydrolysis resistance. Melamine cyanurate is preferred, as the polyurethane filler prepared with it achieves the highest levels of both flame retardancy and hydrolysis resistance.

[0019] To address the aforementioned technical problems, a second objective of this invention is to provide a method for preparing a polyurethane filler adhesive, comprising the following steps: S1. Mix the soft segment, hard segment, amine chain extender and organic solvent evenly, and stir at 50-95 °C for 8-16 h to carry out the polymerization reaction to obtain hydrophobic polyurethane. S2. The triisopropanolamine, carbodiimide-based anti-hydrolysis agent and epoxysilane-based anti-hydrolysis agent are added sequentially to an organic solvent and stirred until homogeneous to obtain the anti-hydrolysis agent. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in an organic solution, pour into a mold and cure at 80-120 ℃ for 4-10 h to obtain polyurethane filler.

[0020] This application uses the above-mentioned optimized polymerization and curing process parameters to prepare hydrophobic polyurethane and polyurethane filler, ensuring that each functional component is uniformly dispersed, so that the functions of hydrophobic modification, hydrolysis resistance, thermal conductivity, and flame retardancy work synergistically. It is especially suitable for the stringent requirements of material stability in harsh environments such as high-voltage cables, and achieves long-term stability of each performance.

[0021] In some embodiments, in S1, the organic solvent has a mass fraction of 70%-90% in the system.

[0022] In some embodiments, in S2, the organic solvent has a mass fraction of 70%-90% in the system.

[0023] In some embodiments, in S3, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the organic solvent is 1:(1-3).

[0024] In some embodiments, the organic solvent in S1, S2, and S3 is tetrahydrofuran.

[0025] To address the aforementioned technical problems, a third objective of this invention is to provide an application of polyurethane filler in the field of cable materials.

[0026] Compared with the prior art, the present invention has the following beneficial effects: 1. This application modifies the molecular structure of hydrophobic polyurethane by using soft segments containing hydrophobic groups to effectively reduce water molecule adsorption and penetration. At the same time, it uses a ternary compound anti-hydrolysis agent to synergistically improve the anti-hydrolysis ability. The epoxy groups of the epoxy silane anti-hydrolysis agent undergo a cross-linking reaction with the hydrophobic polyurethane molecular chain and the hydroxyl groups of triisopropanolamine. After hydrolysis, a stable siloxane (Si-O-Si) cross-linking network is formed, constructing a dense and highly physically cross-linked network. This physically blocks the water molecule penetration channels and improves the capture efficiency of carbodiimide for carboxylic acids generated by hydrolysis. This avoids the problem of easy hydrolysis of single carbodiimide, achieving long-term anti-hydrolysis protection. This allows the polyurethane filler material to maintain excellent thermal conductivity and flame retardant properties in the harsh environment of high-voltage cable use.

[0027] 2. The thermal conductive agent of this application uses the synergistic effect of multi-dimensional alumina, boron nitride and graphene to construct a continuous thermal conductive path. Compared with the single-component thermal conductive agent system, the use of ternary compound thermal conductive agent can improve the hydrolysis resistance to a certain extent and maintain efficient thermal conduction.

[0028] 3. The flame retardant used in this application is a halogen-free system of magnesium hydroxide, melamine cyanurate and zinc borate. This system improves the flame retardant performance of the material while meeting the requirement of low addition amount. It also solves the performance conflict problem caused by traditional high addition amount functional fillers without affecting the hydrolysis resistance. Detailed Implementation

[0029] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0030] It should be understood that the terminology used in this invention is merely for describing particular embodiments and is not intended to limit the invention. Furthermore, with respect to numerical ranges in this invention, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. Any stated value or intermediate value within a stated range, as well as each smaller range between any other stated value or intermediate value within said range, is also included in this invention. The upper and lower limits of these smaller ranges may be independently included or excluded from the range.

[0031] Unless otherwise stated, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. While only preferred methods and materials have been described herein, any methods and materials similar or equivalent to those described herein may be used in the implementation or testing of this invention. All references to this specification are incorporated by way of citation to disclose and describe methods and / or materials associated with those references. In the event of any conflict with any incorporated reference, the content of this specification shall prevail.

[0032] As used in this article: In these embodiments, unless otherwise specified, the portions and percentages are all by weight.

[0033] "And / or" is used to indicate that one or both of the described situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0034] In the description of this invention, it should be understood that the terms "upper", "lower", "left", "right", "top", "bottom", etc., indicating orientation or positional relationship are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0035] This invention provides a polyurethane filler adhesive comprising the following components in parts by weight: 60-100 parts hydrophobic polyurethane, 1-20 parts anti-hydrolysis agent, 1-8 parts thermal conductive agent, and 1-5 parts flame retardant. The hydrophobic polyurethane is polymerized from soft segments, hard segments and amine chain extenders, wherein the soft segments include at least one of polytetrahydrofuran ether, dihydroxybutyl polydimethylsiloxane, and aminopropyl-terminated polydimethylsiloxane. The anti-hydrolysis agent includes triisopropanolamine, carbodiimide anti-hydrolysis agent and epoxysilane anti-hydrolysis agent in a mass ratio of 1:(1-5):(1-4).

[0036] In some embodiments, the hydrophobic polyurethane is in the range of any one or any two of 60 parts, 65 parts, 70 parts, 75 parts, 80 parts, 85 parts, 90 parts, 95 parts, and 100 parts by weight.

[0037] In some embodiments, the anti-hydrolysis agent is in the range of any one, five, ten, fifteen, or twenty parts by weight, or any combination thereof.

[0038] In some embodiments, the thermal conductive agent is expressed in parts by weight of any one or any two of 1, 2, 3, 4, 5, 6, 7, or 8 parts.

[0039] In some embodiments, the flame retardant is expressed in parts by weight of any one, two, three, four, or five, or in any range between two of these.

[0040] In some embodiments, the anti-hydrolysis agent includes triisopropanolamine, carbodiimide anti-hydrolysis agent and epoxysilane anti-hydrolysis agent in a mass ratio of 1:1:(1-3).

[0041] In some embodiments, the hydrophobic polyurethane is polymerized from soft segments, hard segments, and an amine chain extender in a mass ratio of (1-5):(2-4):1.

[0042] In some embodiments, the hydrophobic polyurethane is polymerized from soft segments, hard segments, and an amine chain extender in a mass ratio of 2:3:1.

[0043] In some embodiments, the hard segment includes at least one of isophorone diisocyanate, diphenylmethane diisocyanate, and toluene diisocyanate.

[0044] In some embodiments, the amine chain extender includes at least one of diethylenetriamine and 3,5-diethyltoluenediamine.

[0045] In some embodiments, the thermal conductive agent includes at least one of aluminum oxide, boron nitride, and graphene.

[0046] In some embodiments, the thermal conductive agent comprises aluminum oxide, boron nitride, and graphene in a mass ratio of (1-3):(1-3):(1-2).

[0047] In some embodiments, the thermal conductive agent comprises aluminum oxide, boron nitride, and graphene in a mass ratio of 1:(1-3):(1-2).

[0048] In some embodiments, the carbodiimide antihydrolysis agent includes at least one of bis(2,6-diisopropylphenyl)carbodiimide and N,N-dicyclohexylcarbodiimide.

[0049] In some embodiments, the epoxy silane anti-hydrolysis agent includes at least one of 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and epoxycyclohexylethyl-terminated polydimethylsiloxane.

[0050] In some embodiments, the flame retardant includes at least one of magnesium hydroxide, melamine cyanurate, and zinc borate.

[0051] This invention also provides a method for preparing a polyurethane filler, comprising the following steps: S1. Mix the soft segment, hard segment, amine chain extender and organic solvent evenly, and stir at 50-95 °C for 8-16 h to carry out the polymerization reaction to obtain hydrophobic polyurethane. S2. The triisopropanolamine, carbodiimide-based anti-hydrolysis agent and epoxysilane-based anti-hydrolysis agent are added sequentially to an organic solvent and stirred until homogeneous to obtain the anti-hydrolysis agent. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in an organic solution, pour into a mold and cure at 80-120 ℃ for 4-10 h to obtain polyurethane filler.

[0052] In some embodiments, in S1, the polymerization temperature is a range of any one or any two of 50 ℃, 55 ℃, 60 ℃, 65 ℃, 70 ℃, 75 ℃, 80 ℃, 85 ℃, 90 ℃, and 95 ℃.

[0053] In some implementations, in S1, the polymerization time is a range of any one or any two of 8 h, 9 h, 10 h, 11 h, 12 h, 13 h, 14 h, 15 h, and 16 h.

[0054] In some embodiments, in S3, the curing reaction temperature is a range of any one or any two of 80 ℃, 85 ℃, 90 ℃, 95 ℃, 100 ℃, 105 ℃, 110 ℃, 115 ℃, and 120 ℃.

[0055] In some implementations, in S3, the curing reaction time is any one or a range between any two of 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, and 10 h.

[0056] In some embodiments, in S1, the organic solvent has a mass fraction of 70%-90% in the system.

[0057] In some embodiments, in S2, the organic solvent has a mass fraction of 70%-90% in the system.

[0058] In some embodiments, in S3, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the organic solvent is 1:(1-3).

[0059] In some embodiments, the organic solvent in S1, S2, and S3 is tetrahydrofuran.

[0060] The present invention also provides an application of polyurethane filler in the field of cable materials.

[0061] To further illustrate the present invention, the following detailed description is provided in conjunction with embodiments, but these should not be construed as limiting the scope of protection of the present invention. Unless otherwise specified, the raw materials used in the following embodiments and comparative examples are all commercially available, and the same raw materials were used in parallel experiments.

[0062] Example 1 A polyurethane filler adhesive comprises 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent comprises triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent comprises alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0063] The preparation method of the above-mentioned polyurethane filler includes the following steps: S1. Hydroxybutyl polydimethylsiloxane, isophorone diisocyanate, diethylenetriamine and tetrahydrofuran are mixed evenly, with the mass fraction of tetrahydrofuran in the system being 80%. The mixture is stirred at 80 °C for 10 hours to obtain hydrophobic polyurethane. S2. Triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidoxypropyltrimethoxysilane were added sequentially to a tetrahydrofuran solution. The mass fraction of tetrahydrofuran in the system was 83%. The mixture was stirred at 40 °C for 25 minutes. The system was a transparent solution, and the hydrolysis inhibitor was obtained. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in a tetrahydrofuran solution. At this time, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the mass ratio of tetrahydrofuran is 1:2. Pour the mixed solution into a mold and cure it at 100 °C for 8 h to obtain polyurethane filler.

[0064] Example 2 A polyurethane filler adhesive comprises 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 10 g of polytetrahydrofuran ether, 20 g of diphenylmethane diisocyanate and 10 g of 3,5-diethyltoluene diamine. The anti-hydrolysis agent comprises triisopropanolamine, N,N-dicyclohexylcarbodiimide and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane in a mass ratio of 1:1:4. The thermal conductive agent comprises alumina, boron nitride and graphene in a mass ratio of 1:1:2. The flame retardant is magnesium hydroxide.

[0065] The preparation method of the above-mentioned polyurethane filler includes the following steps: S1. Polytetrahydrofuran ether, diphenylmethane diisocyanate, 3,5-diethyltoluenediamine and tetrahydrofuran are mixed evenly, with the mass fraction of tetrahydrofuran in the system being 80%. The polymerization reaction is carried out by stirring at 80 °C for 8 hours to obtain hydrophobic polyurethane. S2. Triisopropanolamine, N,N-dicyclohexylcarbodiimide and 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane were added sequentially to a tetrahydrofuran solution. The mass fraction of tetrahydrofuran in the system was 83%. The mixture was stirred at 40 °C for 25 minutes. The system was a transparent solution, and the hydrolysis inhibitor was obtained. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in a tetrahydrofuran solution. At this time, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the mass ratio of tetrahydrofuran is 1:2. Pour the mixed solution into a mold and cure it at 80 °C for 4 h to obtain polyurethane filler.

[0066] Example 3 A polyurethane filler adhesive comprises 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 50 g of aminopropyl-terminated polydimethylsiloxane, 20 g of toluene diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent comprises triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and epoxycyclohexylethyl-terminated polydimethylsiloxane in a mass ratio of 1:5:1. The thermal conductive agent comprises alumina, boron nitride and graphene in a mass ratio of 1:3:1. The flame retardant is zinc borate.

[0067] The preparation method of the above-mentioned polyurethane filler includes the following steps: S1. Mix aminopropyl-terminated polydimethylsiloxane, toluene diisocyanate, diethylenetriamine and tetrahydrofuran evenly, with tetrahydrofuran having a mass fraction of 80% in the system. Stir at 80 °C for 16 hours to carry out the polymerization reaction to obtain hydrophobic polyurethane. S2. Triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and epoxycyclohexylethyl-terminated polydimethylsiloxane were added sequentially to a tetrahydrofuran solution. The mass fraction of tetrahydrofuran in the system was 83%. The mixture was stirred at 40 °C for 25 minutes. The system was a transparent solution, and the anti-hydrolysis agent was obtained. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in a tetrahydrofuran solution. At this time, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the mass ratio of tetrahydrofuran is 1:2. Pour the mixed solution into a mold and cure it at 120 °C for 10 h to obtain polyurethane filler.

[0068] Example 4 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the components in the anti-hydrolysis agent are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:4. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0069] Example 5 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the components in the anti-hydrolysis agent are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:5:1. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0070] Example 6 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the components in the hydrophobic polyurethane are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 30 g of dihydroxybutyl polydimethylsiloxane, 20 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0071] Example 7 A polyurethane filler adhesive is prepared in the same way as in Example 1, with the same steps, reagents, equipment, and process parameters. The difference lies in the different proportions of the components in the hydrophobic polyurethane. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent, and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 10 g of dihydroxybutyl polydimethylsiloxane, 40 g of isophorone diisocyanate, and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide, and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride, and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0072] Example 8 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the thermal conductive agent is different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent is alumina and the flame retardant is melamine cyanurate.

[0073] Example 9 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the thermal conductive agent is different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent is boron nitride and the flame retardant is melamine cyanurate.

[0074] Example 10 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the thermal conductive agent is different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent is graphene and the flame retardant is melamine cyanurate.

[0075] Example 11 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the thermal conductive components are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:1:2. The flame retardant is melamine cyanurate.

[0076] Example 12 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the thermal conductive components are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:3:1. The flame retardant is melamine cyanurate.

[0077] Example 13 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the proportions of the thermal conductive components are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 3:2:1. The flame retardant is melamine cyanurate.

[0078] Example 14 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the flame retardant components are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is magnesium hydroxide.

[0079] Example 15 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the flame retardant components are different. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is zinc borate.

[0080] Comparative Example 1 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the dihydroxybutyl polydimethylsiloxane is replaced by polybutylene adipate diol in equal amounts. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of polybutylene adipate diol, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0081] Comparative Example 2 A polyurethane filler adhesive is prepared in the same way as that in Example 1, except that the dihydroxybutyl polydimethylsiloxane is replaced by an equal amount of methyl-terminated polydimethylsiloxane. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of methyl-terminated polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide and 3-glycidoxypropyltrimethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0082] Comparative Example 3 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same reagents, equipment and process parameters. The difference is that the content of the anti-hydrolysis agent is 0. Specifically, it includes 70 g of hydrophobic polyurethane, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0083] Comparative Example 4 A polyurethane filler adhesive is prepared in the same manner as in Example 1, with the same steps, reagents, equipment, and process parameters. The difference lies in the substitution of 3-glycidyl etheroxypropyltrimethoxysilane with an equal amount of aminopropyltriethoxysilane. Specifically, it comprises 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent, and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate, and 10 g of diethylenetriamine. The anti-hydrolysis agent comprises triisopropanolamine, bis(2,6-diisopropylphenyl)carbodiimide, and aminopropyltriethoxysilane in a mass ratio of 1:1:2. The thermal conductive agent comprises alumina, boron nitride, and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0084] Comparative Example 5 A polyurethane filler adhesive is prepared in the same way as that in Example 1, with the same steps, reagents, equipment and process parameters. The difference is that the content of triisopropanolamine is 0. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes 1:1 di(2,6-diisopropylphenyl)carbodiimide and 3-glycidyl etheroxypropyltrimethoxysilane. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0085] Comparative Example 6 A polyurethane filler adhesive is prepared in the same way as in Example 1, except that the contents of bis(2,6-diisopropylphenyl)carbodiimide and triisopropanolamine are 0. Specifically, it includes 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent includes 40 g of 3-glycidyl etheroxypropyltrimethoxysilane. The thermal conductive agent includes alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0086] Comparative Example 7 A polyurethane filler adhesive, the preparation method of which is the same as that in Example 1 in terms of each step, reagents, equipment and process parameters, except that the content of triisopropanolamine and 3-glycidyl etheroxypropyltrimethoxysilane is 0, and the adhesive comprises 70 g of hydrophobic polyurethane, 15 g of anti-hydrolysis agent, 5 g of thermal conductive agent and 2 g of flame retardant. The hydrophobic polyurethane is polymerized from 20 g of dihydroxybutyl polydimethylsiloxane, 30 g of isophorone diisocyanate and 10 g of diethylenetriamine. The anti-hydrolysis agent comprises 40 g of bis(2,6-diisopropylphenyl)carbodiimide. The thermal conductive agent comprises alumina, boron nitride and graphene in a mass ratio of 1:2:1.5. The flame retardant is melamine cyanurate.

[0087] Table 1 - Components and Contents in the Polyurethane Filler of the Examples and Comparative Examples of this Application Performance testing 1. The polyurethane fillers prepared in the examples and comparative examples were placed in a constant temperature and humidity test chamber at 85 ℃ and 95% humidity for 7 days to test the anti-hydrolysis aging properties of the polyurethane fillers before and after aging. The test results are shown in Table 2 below.

[0088] Among them, the thermal conductivity was tested according to the standard GB / T42919.4-2023 "Determination of thermal conductivity and thermal diffusivity of plastics" to measure the thermal conductivity of polyurethane filler before and after the hydrolysis aging test. Among them, the mechanical properties were tested according to the standard GB / T1040.1-2018 "Determination of Tensile Properties of Plastics" to measure the tensile strength of polyurethane filler before and after the hydrolysis aging test. Among them, the flame retardant performance was tested according to the standard GB / T 2406.2-2009 "Determination of Combustion Behavior by Oxygen Index Method for Plastics" to measure the limiting oxygen index of polyurethane filler before and after the hydrolysis aging test.

[0089] Table 2 - Performance test results of polyurethane fillers in the embodiments and comparative examples of this application As shown in Table 2, the polyurethane filler in this application modifies the molecular structure of hydrophobic polyurethane by using soft segments containing hydrophobic groups, effectively reducing water molecule adsorption and penetration. At the same time, a ternary compound anti-hydrolysis agent is used to synergistically improve the anti-hydrolysis ability. Epoxy silane anti-hydrolysis agents are used as the "physical barrier cornerstone." Their epoxy groups undergo cross-linking reactions with the hydrophobic polyurethane molecular chains and the hydroxyl groups of triisopropanolamine. After hydrolysis, a stable siloxane (Si-O-Si) cross-linking network is formed, constructing a dense, highly physically cross-linked network. This physically blocks the water molecule penetration channels, reduces the water molecule penetration rate and the sensitivity of the molecular chain to hydrolysis. Under this network, the capture efficiency of carbodiimide for carboxylic acids generated by hydrolysis is improved, avoiding the problem of easy hydrolysis of single carbodiimide, achieving long-term anti-hydrolysis protection. This allows the polyurethane filler material to maintain stable thermal conductivity and flame retardant properties in the harsh environment of high-voltage cable use.

[0090] Compared to Example 1, the hydrophobic polyurethane soft segment in Comparative Example 1 uses polybutylene adipate diol. Polybutylene adipate diol's molecular chain contains numerous ester bonds, which are sensitive sites for hydrolysis. Under humid or alternating hot and humid conditions, these ester bonds are easily attacked and broken by water molecules, leading to molecular chain degradation. In contrast, the dihydroxybutylated polydimethylsiloxane soft segment used in Example 1 lacks ester bond structures and possesses hydrophobic groups, which can inhibit hydrolysis at its source. Compared to Comparative Example 1, this effectively improves the stability of thermal conductivity and flame retardant properties after the hydrolysis resistance test.

[0091] Compared to Example 1, the soft segment of the hydrophobic polyurethane in Comparative Example 2 uses methyl-terminated polydimethylsiloxane, which does not contain active functional groups and has poor compatibility with the system. This results in an insufficiently dense physical cross-linking network after polymerization, which not only affects the mechanical properties of the material, causing a sharp drop in tensile strength, but also fails to effectively block the water molecule penetration channels. This leads to the easy hydrolysis of bis(2,6-diisopropylphenyl)carbodiimide, which cannot effectively capture the carboxylic acid produced by hydrolysis. Ultimately, the thermal conductivity and flame retardant properties of the material deteriorate under high temperature and high humidity environments, resulting in insufficient stability.

[0092] Compared to Example 1, the polyurethane filler in Comparative Example 3 did not contain any anti-hydrolysis agent. The system relied solely on the molecular structure modification of hydrophobic polyurethane to improve its anti-hydrolysis ability. It used soft segments containing hydrophobic groups, which could reduce water molecule adsorption and penetration to a certain extent, but lacked the synergistic effect of anti-hydrolysis agent. Its anti-hydrolysis ability was far lower than that of Example 1, resulting in a decrease in the thermal conductivity and flame retardant stability of the material in high temperature and high humidity environments.

[0093] Compared to Example 1, in Comparative Example 4, 3-glycidoxypropyltrimethoxysilane was replaced with aminopropyltriethoxysilane as the anti-hydrolysis agent. The 3-glycidoxypropyltrimethoxysilane in Example 1 of this application belongs to the epoxy silane class of anti-hydrolysis agents. Its core function is to cross-link the epoxy groups in the molecule with the hydrophobic polyurethane molecular chain and other anti-hydrolysis agent components (such as the hydroxyl groups of triisopropanolamine and the amino groups of carbodiimide). After hydrolysis, a stable siloxane (Si-O-Si) cross-linking network is formed. This network can not only physically block the penetration of water molecules, but also enhance the compatibility of the system and form a synergistic anti-hydrolysis effect with carbodiimide and triisopropanolamine. In contrast, aminopropyltriethoxysilane in Comparative Example 4 does not belong to the epoxy silane class of hydrolysis resistant agents. It lacks the high reactivity of epoxy groups and cannot form stable crosslinks with polyurethane molecular chains and other hydrolysis resistant agent components. As a result, water molecules can easily penetrate and cannot form a synergistic hydrolysis resistant effect. Therefore, its hydrolysis resistance is poor, and the flame retardancy and thermal conductivity stability of the material in high temperature and high humidity environments are also reduced.

[0094] Compared to Example 1, Comparative Example 5 did not contain triisopropanolamine in its anti-hydrolysis agent. In Example 1 of this application, the addition of triisopropanolamine plays a dual crucial role in the anti-hydrolysis system: firstly, it reacts with the isocyanate groups of the hydrophobic polyurethane to construct a highly dense physical cross-linked network, reducing water molecule intrusion channels; secondly, it regulates the reactivity of the anti-hydrolysis agent system, promoting the reaction between carbodiimides and carboxylic acids generated during hydrolysis, while simultaneously enhancing the cross-linking efficiency of epoxy silanes. In Comparative Example 5, the absence of triisopropanolamine leads to insufficient density of the cross-linked network, increased water molecule penetration rate, and accelerated hydrolysis reaction rate; simultaneously, the carboxylic acid capture efficiency of carbodiimides decreases, resulting in a loss of long-term anti-hydrolysis performance; ultimately, the mechanical and thermal properties of the material degrade more rapidly under high temperature and high humidity environments, failing to meet the harsh environmental requirements for high-voltage cables.

[0095] Compared to Example 1, Comparative Example 6 uses a single 3-glycidyl etheroxypropyltrimethoxysilane anti-hydrolysis agent. Because it lacks triisopropanolamine, the density of the physical cross-linking network in the system is reduced, making it unable to effectively block water molecule penetration channels. Furthermore, it cannot utilize carbodiimides to capture the carboxylic acid produced by hydrolysis, resulting in poor hydrolysis resistance. This leads to deterioration of the material's thermal conductivity and flame retardant properties under high temperature and humidity conditions, and insufficient stability. Comparative Example 7 uses a single bis(2,6-diisopropylphenyl)carbodiimide anti-hydrolysis agent. It cannot utilize triisopropanolamine and 3-glycidyl etheroxypropyltrimethoxysilane to form a dense physical cross-linking network with the hydrophobic polyurethane. This increases water molecule penetration channels, making bis(2,6-diisopropylphenyl)carbodiimide prone to hydrolysis. The system's hydrolysis resistance is extremely poor, and the material's performance stability under high temperature and humidity conditions is insufficient, failing to meet application requirements.

[0096] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above descriptions are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. In particular, it should be noted that any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention for those skilled in the art.

Claims

1. A polyurethane filler adhesive, characterized in that, It includes the following components by weight: 60-100 parts hydrophobic polyurethane, 1-20 parts anti-hydrolysis agent, 1-8 parts thermal conductive agent, and 1-5 parts flame retardant; The hydrophobic polyurethane is polymerized from soft segments, hard segments and amine chain extenders, wherein the soft segments include at least one of polytetrahydrofuran ether, dihydroxybutyl polydimethylsiloxane, and aminopropyl-terminated polydimethylsiloxane. The anti-hydrolysis agent includes triisopropanolamine, carbodiimide anti-hydrolysis agent and epoxysilane anti-hydrolysis agent in a mass ratio of 1:(1-5):(1-4).

2. The polyurethane filler adhesive as described in claim 1, characterized in that, The hydrophobic polyurethane is polymerized from soft segments, hard segments and amine chain extenders in a mass ratio of (1-5):(2-4):

1.

3. The polyurethane filler adhesive as described in claim 1, characterized in that, The hard segment includes at least one of isophorone diisocyanate, diphenylmethane diisocyanate, and toluene diisocyanate; And / or, the amine chain extender includes at least one of diethylenetriamine and 3,5-diethyltoluenediamine.

4. The polyurethane filler adhesive as described in claim 1, characterized in that, The thermal conductive agent includes at least one of aluminum oxide, boron nitride, and graphene.

5. The polyurethane filler adhesive as described in claim 4, characterized in that, The thermal conductive agent comprises aluminum oxide, boron nitride, and graphene in a mass ratio of 1:(1-3):(1-2).

6. The polyurethane filler adhesive as described in claim 1, characterized in that, The carbodiimide antihydrolysis agent includes at least one of bis(2,6-diisopropylphenyl)carbodiimide and N,N-dicyclohexylcarbodiimide; And / or, the epoxy silane anti-hydrolysis agent includes at least one of 3-glycidoxypropyltrimethoxysilane, 2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, and epoxycyclohexylethyl-terminated polydimethylsiloxane.

7. The polyurethane filler adhesive as described in claim 1, characterized in that, The flame retardant includes at least one of magnesium hydroxide, melamine cyanurate, and zinc borate.

8. A method for preparing a polyurethane filler as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix the soft segment, hard segment, amine chain extender and organic solvent evenly, and stir at 50-95 °C for 8-16 h to carry out the polymerization reaction to obtain hydrophobic polyurethane. S2. The triisopropanolamine, carbodiimide-based anti-hydrolysis agent and epoxysilane-based anti-hydrolysis agent are added sequentially to an organic solvent and stirred until homogeneous to obtain the anti-hydrolysis agent. S3. Mix the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant evenly in an organic solution, pour into a mold and cure at 80-120 ℃ for 4-10 h to obtain polyurethane filler.

9. The method for preparing the polyurethane filler as described in claim 8, characterized in that, In S1, the organic solvent has a mass fraction of 70%-90% in the system; And / or, in S2, the organic solvent has a mass fraction of 70%-90% in the system; And / or, in S3, the total mass ratio of the hydrophobic polyurethane, anti-hydrolysis agent, thermal conductive agent and flame retardant to the organic solvent is 1:(1-3). And / or, in S1, S2, and S3, the organic solvent is tetrahydrofuran.

10. An application of a polyurethane filler as described in any one of claims 1-7 in the field of cable materials.

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